WO2024166802A1

WO2024166802A1 - Actinic-ray-sensitive or radiation-sensitive resin composition, actinic-ray-sensitive or radiation-sensitive film, pattern formation method, electronic device manufacturing method, resin, and resin manufacturing method

Info

Publication number: WO2024166802A1
Application number: PCT/JP2024/003409
Authority: WO
Inventors: 英治福▲崎▼
Original assignee: 富士フイルム株式会社
Priority date: 2023-02-06
Filing date: 2024-02-02
Publication date: 2024-08-15

Abstract

Provided are: an actinic-ray-sensitive or radiation-sensitive resin composition comprising (A) a resin containing at least one type of repeating unit expressed by general formula (1) and at least one type of repeating unit expressed by general formula (2) described in the specification, (B) a compound that generates an acid upon irradiation with actinic rays or radiation, and (S) a solvent; an actinic-ray-sensitive or radiation-sensitive film in which the aforementioned actinic-ray-sensitive or radiation-sensitive resin composition is used; a pattern formation method; an electronic device manufacturing method; a resin that can be used in the actinic-ray-sensitive or radiation-sensitive resin composition; and a resin manufacturing method.

Description

Actinic ray-sensitive or radiation-sensitive resin composition, actinic ray-sensitive or radiation-sensitive film, pattern forming method, method for manufacturing electronic device, resin, and method for manufacturing resin

The present invention relates to an actinic ray-sensitive or radiation-sensitive resin composition, an actinic ray-sensitive or radiation-sensitive film, a pattern forming method, and an electronic device manufacturing method. More specifically, the present invention relates to an actinic ray-sensitive or radiation-sensitive resin composition, an actinic ray-sensitive or radiation-sensitive film, a pattern forming method, an electronic device manufacturing method, and a resin that can be used in the actinic ray-sensitive or radiation-sensitive resin composition, which can be suitably used in an ultra-microlithography process applicable to a manufacturing process of a VLSI (Large Scale Integration) and a high-capacity microchip, a mold making process for nanoimprinting, and a manufacturing process of a high-density information recording medium, as well as other photofabrication processes.
The present invention also relates to a method for producing the resin.

Traditionally, in the manufacturing process of semiconductor devices such as ICs (Integrated Circuits) and LSIs (Large Scale Integration), fine processing is performed by lithography using a resist composition. In recent years, with the increasing integration of integrated circuits, there has been a demand for ultra-fine pattern formation in the submicron or quarter-micron range. Accordingly, there has been a trend toward shorter exposure wavelengths, from g-line to i-line and then to KrF excimer laser light, and currently an exposure machine using an ArF excimer laser with a wavelength of 193 nm as a light source has been developed. In addition, as a technology for further increasing resolution, the so-called immersion method, in which a high refractive index liquid (hereinafter also referred to as "immersion liquid") is filled between the projection lens and the sample, has been developed.

Currently, in addition to excimer laser light, lithography using electron beams (EB), X-rays, extreme ultraviolet rays (EUV), and other light sources is also being developed. Accordingly, various resist compositions that are effectively sensitive to various types of actinic rays or radiation have been developed.

Furthermore, various manufacturing methods are known for manufacturing resins used in resist compositions (for example, Patent Document 1).

Japanese Patent Publication No. 10-288839

Recently, the performance required of resist compositions has become increasingly high. In particular, there is a demand for improved resolution, line width roughness (LWR) performance, and pattern shape when forming fine patterns. LWR performance refers to the ability to reduce the LWR of a pattern.

Therefore, an object of the present invention is to provide an actinic ray-sensitive or radiation-sensitive resin composition that is excellent in resolution and LWR performance.
Another object of the present invention is to provide an actinic ray-sensitive or radiation-sensitive film formed using the actinic ray-sensitive or radiation-sensitive resin composition, a pattern formation method using the actinic ray-sensitive or radiation-sensitive resin composition, a method for producing an electronic device, and a resin that can be used in the actinic ray-sensitive or radiation-sensitive resin composition.
A further object of the present invention is to provide a method for producing a resin.

The inventors have discovered that the above problems can be solved by the following configuration.

[1]
A resin (A) containing at least one kind of repeating unit represented by the following general formula (1) and at least one kind of repeating unit represented by the following general formula (2):
A compound (B) that generates an acid when exposed to actinic rays or radiation, and a solvent (S).
An actinic ray-sensitive or radiation-sensitive resin composition comprising:

In general formula (1), R ₁₁ represents an organic group, a halogen atom, or a hydroxyl group. R ₁₂ represents a hydrogen atom or an organic group. A ¹ represents an aromatic hydrocarbon group or an aromatic heterocyclic group. n1 represents an integer of 0 to 5. When n1 is an integer of 2 to 5, multiple R ₁₁ may be the same or different and may be bonded to form a ring. R ₁₂ and A ¹ may be bonded to form a ring.
In general formula (2), R ₂₁ represents an organic group, a halogen atom, or a hydroxyl group. R ₂₂ represents an organic group or a halogen atom. A ² represents an aromatic hydrocarbon group or an aromatic heterocyclic group. n2 represents an integer of 0 to 5. When n2 is an integer of 2 to 5, multiple R ₂₁ may be the same or different and may be bonded to form a ring.

[2]
The actinic ray-sensitive or radiation-sensitive resin composition according to [1], wherein the content of the repeating unit represented by the general formula (2) is 30 to 60 mol % relative to all repeating units in the resin (A).

[3]
The actinic ray-sensitive or radiation-sensitive resin composition according to [1] or [2], wherein the resin (A) has a weight average molecular weight of 4,000 or more.
[4]
The actinic ray-sensitive or radiation-sensitive resin composition according to any one of [1] to [3], wherein A ¹ in the general formula (1) and A ² in the general formula (2) are aromatic ring hydrocarbon groups.

[5]
A method for producing a resin by polymerizing at least two types of monomers in the presence of a nitroxide radical represented by the following general formula (N) and a radical polymerization initiator to produce a resin (X) containing at least two types of repeating units represented by the following general formula (3):

In formula (N), R ₁ each independently represents an organic group. Two R ₁ may be bonded to form a ring.

In general formula (3), R ₃₁ represents an organic group, a halogen atom, or a hydroxyl group. R ₃₂ represents a hydrogen atom, an organic group, or a halogen atom. R ₃₃ represents a hydrogen atom or an organic group. A ³ represents an aromatic hydrocarbon group, or an aromatic heterocyclic group. n3 represents an integer of 0 to 5. When n3 is an integer of 2 to 5, multiple R ₃₁ may be the same or different and may be bonded to form a ring. R ₃₃ and A ³ may be bonded to form a ring.

[6]
The method for producing a resin according to [5], wherein the resin (X) contains at least one type of repeating unit represented by the following general formula (4) and at least one type of repeating unit represented by the following general formula (5):

In general formula (4), R ₄₁ represents an organic group, a halogen atom, or a hydroxyl group. R ₄₂ represents a hydrogen atom or an organic group. A ⁴ represents an aromatic hydrocarbon group or an aromatic heterocyclic group. n4 represents an integer of 0 to 5. When n4 is an integer of 2 to 5, multiple R ₄₁ may be the same or different and may be bonded to form a ring. R ₄₂ and A ⁴ may be bonded to form a ring.
In general formula (5), R ₅₁ represents an organic group, a halogen atom, or a hydroxyl group. R ₅₂ represents an organic group or a halogen atom. A ⁵ represents an aromatic hydrocarbon group or an aromatic heterocyclic group. n5 represents an integer of 0 to 5. When n5 is an integer of 2 to 5, multiple R ₅₁ may be the same or different and may be bonded to form a ring.

[7]
The method for producing a resin according to [6], wherein the content of the repeating unit represented by the general formula (5) in the resin (X) is 30 to 60 mol % relative to all repeating units in the resin (X).
[8]
The method for producing a resin according to [6] or [7], wherein the resin (X) has a weight average molecular weight of 4,000 or more.

[9]
The method for producing a resin according to any one of [6] to [8], wherein A ⁴ in the general formula (4) and A ⁵ in the general formula (5) are aromatic ring hydrocarbon groups.
[10]
The method for producing a resin according to any one of [6] to [9], wherein R ₅₂ in the general formula (5) is an alkyl group.

[11]
The method for producing a resin according to [5], wherein the resin (X) contains at least two kinds of repeating units represented by the following general formula (6), or is produced via a resin (P2) containing at least one kind each of a repeating unit represented by the above general formula (6) and a repeating unit represented by the following general formula (7) different from the repeating unit represented by the above general formula (6).

In general formula (6), R ₆₁ represents a group that generates an -OH group or a -COOH group upon decomposition by a base. R ₆₂ represents a hydrogen atom, an organic group, or a halogen atom. A ⁶ represents an aromatic hydrocarbon group or an aromatic heterocyclic group. n6 represents an integer of 1 to 5. When n6 is an integer of 2 to 5, multiple R ₆₁ may be the same or different.
In general formula (7), R ₇₁ represents an organic group or a halogen atom. R ₇₂ represents a hydrogen atom, an organic group, or a halogen atom. A ⁷ represents an aromatic hydrocarbon group, or an aromatic heterocyclic group. n7 represents an integer of 0 to 5. When n7 is an integer of 2 to 5, multiple R ₇₁ may be the same or different and may be bonded to form a ring.

[12]
The method for producing a resin according to [11], wherein R ₆₁ in the above general formula (6) is a group represented by any one of the following general formulas (8) to (15):

In formulae (8) to (15), R ₉₁ , R ₁₀₁ , R ₁₁₁ , R ₁₂₁ , R ₁₄₁ and R ₁₅₁ each independently represent an organic group, R ₈₁ and R ₁₃₁ each independently represent a hydrogen atom or an organic group. * represents the bonding position with A ⁶ .

[13]
The method for producing a resin according to [12], wherein R ₆₁ in the general formula (6) contains at least two kinds of repeating units that are groups represented by any one of the general formulae (8) to (15).
[14]
The method for producing a resin according to [11], wherein R ₇₁ in the general formula (7) is a group that generates an —OH group or a —COOH group upon acid decomposition.

[15]
The method for producing a resin according to [14], wherein R ₇₁ in the above general formula (7) is a group represented by any one of the following general formulas (16) to (17):

In formula (16), R ₁₆₁ to R ₁₆₃ each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, a heteroaryl group, an alkenyl group, or an alkynyl group. R ₁₆₁ to R ₁₆₃ may be linked to each other to form a ring.
In formula (17), R ₁₇₁ and R ₁₇₂ each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, a heteroaryl group, an alkenyl group, or an alkynyl group. R ₁₇₃ represents an alkyl group, a cycloalkyl group, an aryl group, a heteroaryl group, an alkenyl group, or an alkynyl group. R ₁₇₁ to R ₁₇₃ may be linked together to form a ring.
* indicates the bonding position with ^A7 .
[16]
The method for producing a resin according to [11], wherein the repeating unit represented by the above general formula (7) is a repeating unit represented by the following general formula (18):

In general formula (18), R ₁₈₄ represents a hydrogen atom, an organic group, or a halogen atom. A ¹⁸ represents an aromatic hydrocarbon group, or an aromatic heterocyclic group. R ₁₈₁ to R ₁₈₃ each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, a heteroaryl group, an alkenyl group, or an alkynyl group. Two of R ₁₈₁ to R ₁₈₃ may be bonded to each other to form a ring.

[17]
The method for producing a resin according to [11], wherein the resin (P2) contains at least two kinds of repeating units in which ^A6 in the general formula (6) is an aromatic ring hydrocarbon group, or contains at least one kind each of a repeating unit in which ^A6 in the general formula (6) is an aromatic ring hydrocarbon group and a repeating unit in which ^A7 in the general formula (7) is an aromatic ring hydrocarbon group.

[18]
A resin containing at least one type of repeating unit represented by the following general formula (1) and at least one type of repeating unit represented by the following general formula (2):

[19]
The resin according to [18], wherein the content of the repeating unit represented by the general formula (2) is 30 to 60 mol % relative to all repeating units in the resin.
[20]
The resin according to [18] or [19], having a weight average molecular weight of 4,000 or more.

[21]
The resin according to any one of [18] to [20], wherein A ¹ in the general formula (1) and A ² in the general formula (2) are aromatic ring hydrocarbon groups.
[22]
An actinic ray-sensitive or radiation-sensitive film formed using the actinic ray-sensitive or radiation-sensitive resin composition according to any one of [1] to [4].

[23]
A pattern forming method comprising the steps of: forming an actinic ray-sensitive or radiation-sensitive film on a substrate from the actinic ray-sensitive or radiation-sensitive resin composition according to any one of items [1] to [4]; exposing the actinic ray-sensitive or radiation-sensitive film; and developing the exposed actinic ray-sensitive or radiation-sensitive film with a developer.
[24]
A method for producing an electronic device, comprising the pattern formation method according to [23].

According to the present invention, it is possible to provide an actinic ray-sensitive or radiation-sensitive resin composition having excellent resolution and LWR performance.
Furthermore, the present invention can provide an actinic ray-sensitive or radiation-sensitive film using the actinic ray-sensitive or radiation-sensitive resin composition, a pattern forming method, a method for producing an electronic device, and a resin that can be used in the actinic ray-sensitive or radiation-sensitive resin composition.
Furthermore, the present invention can provide a method for producing a resin.

The present invention will be described in detail below.
The following description of the components may be based on a representative embodiment of the present invention, but the present invention is not limited to such an embodiment.

In this specification, "actinic rays" or "radiation" refers to, for example, the emission line spectrum of a mercury lamp, far ultraviolet rays represented by excimer lasers, extreme ultraviolet rays (EUV: Extreme Ultraviolet), X-rays, soft X-rays, and electron beams (EB: Electron Beam).
In this specification, "light" means actinic rays or radiation.
In this specification, unless otherwise specified, "exposure" includes not only exposure to the emission line spectrum of a mercury lamp, far ultraviolet light represented by an excimer laser, extreme ultraviolet light, X-rays, EUV, and the like, but also drawing with particle beams such as electron beams and ion beams.
In this specification, the word "to" is used to mean that the numerical values before and after it are included as the lower limit and upper limit.

In this specification, (meth)acrylate refers to at least one of acrylate and methacrylate. Also, (meth)acrylic acid refers to at least one of acrylic acid and methacrylic acid.

In this specification, the weight average molecular weight (Mw), number average molecular weight (Mn), and dispersity (also called molecular weight distribution) (Mw/Mn) of the resin are defined as polystyrene equivalent values measured using a Gel Permeation Chromatography (GPC) device (Tosoh Corporation HLC-8120GPC) (solvent: tetrahydrofuran, flow rate (sample injection amount): 10 μL, column: Tosoh Corporation TSK gel Multipore HXL-M, column temperature: 40°C, flow rate: 1.0 mL/min, detector: refractive index detector).

In the present specification, the notation of groups (atomic groups) that does not indicate whether they are substituted or unsubstituted includes groups that have a substituent as well as groups that have no substituent. For example, the term "alkyl group" includes not only alkyl groups that have no substituent (unsubstituted alkyl groups) but also alkyl groups that have a substituent (substituted alkyl groups). In addition, the term "organic group" in the present specification refers to a group that contains at least one carbon atom.
Unless otherwise specified, the substituent is preferably a monovalent substituent. Examples of the substituent include a monovalent nonmetallic atomic group other than a hydrogen atom, and can be selected from the following substituents T.

(Substituent T)
Examples of the substituent T include halogen atoms such as a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom; alkoxy groups such as a methoxy group, an ethoxy group, and a tert-butoxy group; a cycloalkyloxy group; an aryloxy group such as a phenoxy group and a p-tolyloxy group; an alkoxycarbonyl group such as a methoxycarbonyl group and a butoxycarbonyl group; a cycloalkyloxycarbonyl group; an aryloxycarbonyl group such as a phenoxycarbonyl group; an acyloxy group such as an acetoxy group, a propionyloxy group, and a benzoyloxy group; an acetyl group, a benzoyl group, an isobutyryl group, Examples of the substituent T include acyl groups such as acryloyl, methacryloyl, and methoxalyl groups; sulfanyl groups; alkylsulfanyl groups such as methylsulfanyl and tert-butylsulfanyl groups; arylsulfanyl groups such as phenylsulfanyl and p-tolylsulfanyl groups; alkyl groups; alkenyl groups; cycloalkyl groups; aryl groups; aromatic heterocyclic groups; hydroxy groups; carboxyl groups; formyl groups; sulfo groups; cyano groups; alkylaminocarbonyl groups; arylaminocarbonyl groups; sulfonamide groups; silyl groups; amino groups; carbamoyl groups; and the like. In addition, when these substituents can further have one or more substituents, examples of the substituent T also include groups having one or more substituents selected from the above-mentioned substituents as the further substituents (for example, monoalkylamino groups, dialkylamino groups, arylamino groups, trifluoromethyl groups, etc.).

In this specification, the bonding direction of the divalent groups is not limited unless otherwise specified. For example, when Y is -COO- in a compound represented by the formula "X-Y-Z", Y may be -CO-O- or -O-CO-. The above compound may be "X-CO-O-Z" or "X-O-CO-Z".

In this specification, the acid dissociation constant (pKa) refers to the pKa in an aqueous solution, and specifically, it is a value calculated based on a database of Hammett's substituent constants and known literature values using the following software package 1. All pKa values described in this specification are values calculated using this software package.
Software package 1: Advanced Chemistry Development (ACD/Labs) Software V8.14 for Solaris (1994-2007 ACD/Labs).

In addition, pKa can also be obtained by molecular orbital calculation. A specific example of this method is a method of calculating H ⁺ dissociation free energy in an aqueous solution based on a thermodynamic cycle. The H ⁺ dissociation free energy can be calculated, for example, by DFT (density functional theory), but various other methods have been reported in literature, and the calculation method is not limited to this. There are several software programs that can perform DFT, and Gaussian16 is an example.

In this specification, pKa refers to a value calculated based on a database of Hammett's substituent constants and known literature values using the software package 1, as described above. However, when pKa cannot be calculated by this method, a value obtained by Gaussian 16 based on DFT (density functional theory) is adopted.
In this specification, pKa refers to "pKa in an aqueous solution" as described above, but when the pKa in an aqueous solution cannot be calculated, "pKa in a dimethyl sulfoxide (DMSO) solution" will be adopted.

In this specification, "solids" refers to components that form an actinic ray-sensitive or radiation-sensitive film, and does not include solvents. In addition, any component that forms an actinic ray-sensitive or radiation-sensitive film is considered to be a solid even if it is in liquid form.

[Actinic ray-sensitive or radiation-sensitive resin composition]
The actinic ray-sensitive or radiation-sensitive resin composition of the present invention (also referred to as the "composition of the present invention") comprises a repeating unit represented by the following general formula (1) and a repeating unit represented by the following general formula (2): The composition contains a resin (A) containing at least one type of repeating unit, a compound (B) that generates an acid when irradiated with actinic rays or radiation, and a solvent (S).

Although the mechanism by which the composition of the present invention provides the above-mentioned effects has not been fully elucidated, the present inventors presume it as follows.
Resin (A) includes a repeating unit represented by the above general formula (1) and a repeating unit represented by general formula (2). The repeating unit represented by general formula (2) has a substituent at R ₂₂ in general formula (2), that is, the carbon atom in the main chain to which the aromatic ring group is bonded has a substituent, so that the glass transition temperature (Tg) of resin (A) is high. In an actinic ray-sensitive or radiation-sensitive film obtained from an actinic ray-sensitive or radiation-sensitive resin composition containing a resin with a high Tg, the diffusion of an acid generated from a compound that generates an acid upon irradiation with actinic rays or radiation during exposure (hereinafter also referred to as photoacid generator (B)) is suppressed. In addition, as described above, in resin (A), since the carbon atom in the main chain to which the aromatic ring group is bonded has a substituent, steric hindrance becomes large, so that the main chains are less likely to approach each other, and the crosslinking reaction between the main chains is suppressed. Therefore, it is presumed that the resolution and LWR performance are improved.

The composition of the present invention is typically a resist composition, and may be a positive resist composition or a negative resist composition. The composition of the present invention may be a resist composition for alkali development or a resist composition for organic solvent development.
The composition of the present invention may be a chemically amplified resist composition or a non-chemically amplified resist composition. The composition of the present invention is typically a chemically amplified resist composition.
The composition of the present invention can be used to form an actinic ray- or radiation-sensitive film. The actinic ray- or radiation-sensitive film formed using the composition of the present invention is typically a resist film.
First, the various components of the composition of the present invention will be described in detail below.

[Resin (A)]
The resin (A) contained in the composition of the present invention contains at least one type each of the repeating units represented by the above general formula (1) and the repeating units represented by the general formula (2).

In general formula (1), R ₁₁ represents an organic group, a halogen atom, or a hydroxyl group. R ₁₂ represents a hydrogen atom or an organic group. A ¹ represents an aromatic hydrocarbon group or an aromatic heterocyclic group. n1 represents an integer of 0 to 5. When n1 is an integer of 2 to 5, multiple R ₁₁ may be the same or different and may be bonded to form a ring. R ₁₂ and A ¹ may be bonded to form a ring.

In formula (1), R ₁₁ represents an organic group, a halogen atom, or a hydroxyl group.
The organic group represented by R ₁₁ is not particularly limited, but examples thereof include the organic groups exemplified above as the substituent T.
The organic group may, for example, be an organic group having 1 to 30 carbon atoms, preferably an organic group having 1 to 20 carbon atoms, and more preferably an organic group having 1 to 10 carbon atoms.
The organic group may have a heteroatom (for example, a nitrogen atom, an oxygen atom, a sulfur atom, a silicon atom, etc.).
The organic group may be an acid-decomposable group described later, and preferably has a structure in which a phenolic hydroxyl group or a carboxyl group is protected by a group that is eliminated by the action of an acid described later, or is preferably a group represented by any one of the general formulae (16) to (17) described later.
The organic group may also be a group that is decomposed by a base as R ₆₁ described below to generate an --OH group or a --COOH group (also referred to as a "base-decomposable group").
Examples of the halogen atom represented by R ₁₁ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, with a fluorine atom and a chlorine atom being preferred.

Examples of the organic group represented by R ₁₂ include an alkyl group, a cycloalkyl group, an aryl group, and an alkylcarbonyloxy group.
The alkyl group may be linear or branched. The number of carbon atoms in the alkyl group is not particularly limited, but is preferably 1 to 10, and more preferably 1 to 3.
The cycloalkyl group may be either monocyclic or polycyclic, and preferably has 3 to 8 carbon atoms.
The aryl group is preferably an aryl group having 6 to 10 carbon atoms, such as a phenyl group.
The alkyl group in the alkylcarbonyloxy group may be linear or branched. The number of carbon atoms in the alkyl group is not particularly limited, but is preferably 1 to 10, and more preferably 1 to 3.
R ₁₂ is preferably a hydrogen atom or an alkyl group, and more preferably a hydrogen atom.

In formula (1), A ¹ represents an aromatic hydrocarbon group or an aromatic heterocyclic group.
The aromatic hydrocarbon group represented by A ¹ may be, for example, an arylene group having 6 to 15 carbon atoms, and specific preferred examples thereof include a phenylene group, a naphthylene group, and an anthrylene group.
Examples of the aromatic heterocyclic group represented by ^A1 include heteroarylene groups having 2 to 15 carbon atoms, such as 5- to 10-membered rings. Specific examples include groups in which any one hydrogen atom has been removed from a furyl group, a thienyl group, a thiazolyl group, a pyrrolyl group, an oxazolyl group, a pyridyl group, a benzofuranyl group, a benzothienyl group, a quinolinyl group, a carbazolyl group, and the like.

^A1 is preferably an aromatic hydrocarbon group, more preferably a phenylene group.

In general formula (1), n1 represents an integer from 0 to 5. It is preferable that n1 is 1 or 2.

Specific examples of monomers corresponding to the repeating unit represented by general formula (1) are shown below, but the present invention is not limited to these.

The repeating unit represented by general formula (1) in resin (A) may be of one type or of two or more types.

The content ratio of the repeating unit represented by general formula (1) to all repeating units in resin (A) is not particularly limited, but can be, for example, 40 to 99 mol %. It is preferably 40 to 70 mol %, and more preferably 47 to 60 mol %.

In general formula (2), R ₂₁ represents an organic group, a halogen atom, or a hydroxyl group. R ₂₂ represents an organic group or a halogen atom. A ² represents an aromatic hydrocarbon group or an aromatic heterocyclic group. n2 represents an integer of 0 to 5. When n2 is an integer of 2 to 5, multiple R ₂₁ may be the same or different and may be bonded to form a ring.

In formula (2), R ₂₁ represents an organic group, a halogen atom, or a hydroxyl group.
The organic group represented by R ₂₁ is not particularly limited, but examples thereof include the organic groups listed above as the substituent T.
The organic group may, for example, be an organic group having 1 to 30 carbon atoms, preferably an organic group having 1 to 20 carbon atoms, and more preferably an organic group having 1 to 10 carbon atoms.
The organic group may have a heteroatom (for example, a nitrogen atom, an oxygen atom, a sulfur atom, a silicon atom, etc.).
The organic group may be an acid-decomposable group described later, and preferably has a structure in which a phenolic hydroxyl group or a carboxyl group is protected by a group that is eliminated by the action of an acid described later, or is preferably a group represented by any one of the general formulae (16) to (17) described later.
The organic group may also be a group that is decomposed by a base as R ₆₁ described below to generate an --OH group or a --COOH group (also referred to as a "base-decomposable group").
Examples of the halogen atom represented by R ₂₁ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom and a chlorine atom are preferred.

In formula (2), R ₂₂ represents an organic group or a halogen atom.

Examples of the organic group represented by R ₂₂ include an alkyl group, a cycloalkyl group, an aryl group, an acyl group, and an alkylcarbonyloxy group.
The alkyl group may be linear or branched. The number of carbon atoms in the alkyl group is not particularly limited, but is preferably 1 to 10, and more preferably 1 to 3.
The cycloalkyl group may be either monocyclic or polycyclic, and preferably has 3 to 8 carbon atoms.
The aryl group is preferably an aryl group having 6 to 10 carbon atoms, such as a phenyl group.
The acyl group is preferably an acyl group having 1 to 20 carbon atoms.
The alkyl group in the alkylcarbonyloxy group may be linear or branched. The number of carbon atoms in the alkyl group is not particularly limited, but is preferably 1 to 10, and more preferably 1 to 3.

Examples of the halogen atom represented by R ₂₂ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

R ₂₂ is preferably an alkyl group or a halogen atom, more preferably an alkyl group, and further preferably a methyl group.

In formula (2), ^A2 represents an aromatic hydrocarbon group or an aromatic heterocyclic group.
The aromatic hydrocarbon group represented by ^A2 may be, for example, an arylene group having 6 to 15 carbon atoms, and specific preferred examples thereof include a phenylene group, a naphthylene group, and an anthrylene group.
Examples of the aromatic heterocyclic group represented by ^A2 include heteroarylene groups having 2 to 15 carbon atoms, such as 5- to 10-membered rings. Specific examples include groups in which any one hydrogen atom has been removed from a furyl group, a thienyl group, a thiazolyl group, a pyrrolyl group, an oxazolyl group, a pyridyl group, a benzofuranyl group, a benzothienyl group, a quinolinyl group, a carbazolyl group, and the like.

^A2 is preferably an aromatic hydrocarbon group, more preferably a phenylene group.

In the resin (A), ^A1 in the above general formula (1) and ^A2 in the above general formula (2) are preferably aromatic ring hydrocarbon groups.

In general formula (2), n2 represents an integer from 0 to 5. It is preferable that n2 is 1 or 2.

Specific examples of monomers corresponding to the repeating unit represented by general formula (2) are shown below, but the present invention is not limited to these.

The repeating unit represented by general formula (2) in resin (A) may be of one type or of two or more types.

The content ratio of the repeating unit represented by general formula (2) relative to all repeating units in the resin (A) is preferably 1 to 60 mol%, more preferably 30 to 60 mol%, still more preferably 40 to 55 mol%, and still more preferably 40 to 53 mol%.
By making the content ratio of the repeating unit represented by the general formula (2) 30 mol % or more, the glass transition temperature of the resin (A) becomes higher, so that the effect of the present invention can be easily obtained. On the other hand, by making it 60 mol % or less, the thermal decomposition temperature can be lowered and the glass transition temperature can be increased, so that it is preferable.

<Repeating Unit Having Acid-Decomposable Group>
The resin (A) preferably has an acid decomposable group. The resin (A) preferably contains a repeating unit having an acid decomposable group. When the resin (A) is an acid decomposable resin, typically, in the pattern forming method using the composition of the present invention, when an alkaline developer is used as the developer, a positive pattern is preferably formed, and when an organic developer is used as the developer, a negative pattern is preferably formed.

The acid-decomposable group is a group that decomposes under the action of an acid and has an increased polarity.
The acid-decomposable group is typically a group that decomposes under the action of an acid to generate a polar group. The acid-decomposable group preferably has a structure in which a polar group is protected by a group (leaving group) that is eliminated under the action of an acid. Typically, the polarity of the resin (A) increases under the action of an acid, so that the solubility in an alkaline developer increases and the solubility in an organic solvent decreases.
The polar group is preferably an alkali-soluble group, and examples thereof include acidic groups such as a carboxy group, a phenolic hydroxyl group, a fluorinated alcohol group, a sulfonic acid group, a phosphate group, a sulfonamide group, a sulfonylimide group, an (alkylsulfonyl)(alkylcarbonyl)methylene group, an (alkylsulfonyl)(alkylcarbonyl)imide group, a bis(alkylcarbonyl)methylene group, a bis(alkylcarbonyl)imide group, a bis(alkylsulfonyl)methylene group, a bis(alkylsulfonyl)imide group, a tris(alkylcarbonyl)methylene group, and a tris(alkylsulfonyl)methylene group, as well as an alcoholic hydroxyl group.

Examples of the leaving group which is eliminated by the action of an acid include groups represented by the formulae (Y1) to (Y4).
Formula (Y1): -C(Rx ₁ )(Rx ₂ )(Rx ₃ )
Formula (Y2): -C(=O)OC(Rx ₁ )(Rx ₂ )(Rx ₃ )
Formula (Y3): -C(R ₃₆ )(R ₃₇ )(OR ₃₈ )
Formula (Y4): -C(Rn)(H)(Ar)

In formula (Y1) and formula (Y2), Rx ₁ to Rx ₃ each independently represent an alkyl group (linear or branched), a cycloalkyl group (monocyclic or polycyclic), an aryl group (monocyclic or polycyclic), an aralkyl group (linear or branched), or an alkenyl group (linear or branched). When all of Rx ₁ to Rx ₃ are alkyl groups (linear or branched), it is preferable that at least two of Rx ₁ to Rx ₃ are methyl groups.
In particular, it is preferable that Rx ₁ to Rx ₃ each independently represent a linear or branched alkyl group, and it is more preferable that Rx ₁ to Rx ₃ each independently represent a linear alkyl group.
Two of Rx ₁ to Rx ₃ may be bonded to each other to form a ring (which may be either a monocyclic ring or a polycyclic ring).
The alkyl group of Rx ₁ to Rx ₃ is preferably an alkyl group having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group, an isobutyl group, or a t-butyl group.
The cycloalkyl groups of Rx ₁ to Rx ₃ are preferably monocyclic cycloalkyl groups such as a cyclopentyl group and a cyclohexyl group, and polycyclic cycloalkyl groups such as a norbornyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, and an adamantyl group.
The aryl group of Rx ₁ to Rx ₃ is preferably an aryl group having 6 to 10 carbon atoms, and examples thereof include a phenyl group, a naphthyl group, and an anthryl group.
The aralkyl group of Rx ₁ to Rx ₃ is preferably a group in which one hydrogen atom in the alkyl group of Rx ₁ to Rx ₃ described above is substituted with an aryl group having 6 to 10 carbon atoms (preferably a phenyl group), and examples thereof include a benzyl group.
The alkenyl group of Rx ₁ to Rx ₃ is preferably a vinyl group.
The ring formed by combining two of Rx ₁ to Rx ₃ is preferably a cycloalkyl group. The cycloalkyl group formed by combining two of Rx ₁ to Rx ₃ is preferably a monocyclic cycloalkyl group such as a cyclopentyl group or a cyclohexyl group, or a polycyclic cycloalkyl group such as a norbornyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, or an adamantyl group, and more preferably a monocyclic cycloalkyl group having 5 to 6 carbon atoms.
In the cycloalkyl group formed by combining two of _Rx1 to _Rx3 , for example, one of the methylene groups constituting the ring may be replaced with a heteroatom such as an oxygen atom, a group having a heteroatom such as a carbonyl group, or a vinylidene group. In addition, in these cycloalkyl groups, one or more of the ethylene groups constituting the cycloalkane ring may be replaced with a vinylene group.
In the group represented by formula (Y1) or formula (Y2), for example, it is preferable that _Rx1 is a methyl group or an ethyl group, and _Rx2 and _Rx3 are bonded to form the above-mentioned cycloalkyl group.

In formula (Y3), R ₃₆ to R ₃₈ each independently represent a hydrogen atom or a monovalent organic group. R ₃₇ and R ₃₈ may be bonded to each other to form a ring. Examples of the monovalent organic group include an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, and an alkenyl group. It is also preferable that R ₃₆ is a hydrogen atom.
The alkyl group, cycloalkyl group, aryl group, and aralkyl group may contain a heteroatom such as an oxygen atom and/or a group having a heteroatom such as a carbonyl group. For example, the alkyl group, cycloalkyl group, aryl group, and aralkyl group may have one or more methylene groups replaced with a heteroatom such as an oxygen atom and/or a group having a heteroatom such as a carbonyl group.
In addition, R ₃₈ may be bonded to another substituent in the main chain of the repeating unit to form a ring. The group formed by bonding R ₃₈ to another substituent in the main chain of the repeating unit is preferably an alkylene group such as a methylene group.

In formula (Y4), Ar represents an aromatic ring group. Rn represents an alkyl group, a cycloalkyl group, or an aryl group. Rn and Ar may be bonded to each other to form a non-aromatic ring. Ar is more preferably an aryl group.

The content of repeating units having an acid decomposable group is preferably 5 mol% or more, more preferably 10 mol% or more, and even more preferably 15 mol% or more, based on all repeating units in resin (A). The content of repeating units having an acid decomposable group is preferably 70 mol% or less, more preferably 60 mol% or less, and even more preferably 50 mol% or less, based on all repeating units in resin (A).

The repeating unit having an acid-decomposable group contained in the resin (A) may be a repeating unit represented by the above general formula (1), may be a repeating unit represented by general formula (2), or may be any other repeating unit.
The repeating unit having an acid-decomposable group contained in the resin (A) may be one type or two or more types. When the resin (A) contains two or more types of repeating units having an acid-decomposable group, it is preferable that the total content thereof is within the above-mentioned suitable content range.

The resin (A) may contain other repeating units in addition to the repeating unit represented by the above general formula (1), the repeating unit represented by the general formula (2), and the repeating unit having an acid-decomposable group.
For other repeating units, the contents of [0079] to [0172] of WO 2022/024928 are incorporated by reference.

The total content of the repeating units represented by the above general formula (1) and the repeating units represented by the general formula (2) in the resin (A) is not particularly limited, but is preferably 70 mol% or more, more preferably 80 mol% or more, and even more preferably 90 mol% or more.

The method for synthesizing resin (A) is not particularly limited, but it can be synthesized, for example, by radical polymerization. Among them, from the viewpoint of increasing the introduction rate of the repeating unit represented by general formula (2) and obtaining a resin with a high molecular weight, thereby improving the glass transition temperature of the resin, it is preferable to synthesize it using the method for producing the resin of the present invention described later.

The weight average molecular weight (Mw) of the resin (A), as a polystyrene equivalent value measured by the GPC method, is preferably 1000 or more, more preferably 2000 or more, even more preferably 4000 or more, and particularly preferably 5000 or more. Also, it is preferably 30000 or less, more preferably 15000 or less.
The dispersity (molecular weight distribution, Pd, Mw/Mn) of the resin (A) is preferably from 1 to 5, more preferably from 1 to 3, even more preferably from 1.0 to 3.0, and particularly preferably from 1.1 to 2.0. The smaller the dispersity, the better the resolution and resist shape, and furthermore, the smoother the sidewalls of the resist pattern are, and the better the roughness.

In the composition of the present invention, the content of the resin (A) is preferably from 40.0 to 99.9 mass %, more preferably from 60.0 to 90.0 mass %, based on the total solid content of the composition of the present invention.
Resin (A) may be used alone or in combination of two or more. When two or more resins (A) are used, the total content thereof is preferably within the above-mentioned suitable content range.

[Compound (B) that generates an acid upon exposure to actinic rays or radiation]
The composition of the present invention contains a compound (B) that generates an acid when irradiated with actinic rays or radiation (hereinafter, also referred to as photoacid generator (B)). The photoacid generator may be in the form of a low molecular weight compound, or may be incorporated into a part of a polymer. In addition, the low molecular weight compound and the photoacid generator incorporated into a part of a polymer may be used in combination.
When the photoacid generator is in the form of a low molecular weight compound, the molecular weight of the photoacid generator is preferably 3000 or less, more preferably 2000 or less, and even more preferably 1000 or less. There is no particular lower limit, but a molecular weight of 100 or more is preferable.
When the photoacid generator is in a form in which it is incorporated into a part of a polymer, it may be incorporated into a part of the resin (A) or into a resin different from the resin (A).
The photoacid generator is preferably in the form of a low molecular weight compound.
The photoacid generator is preferably a compound that generates an acid having a pKa of −2.0 or more upon irradiation with actinic rays or radiation, and more preferably a compound that generates an acid having a pKa of −2.0 or more and 1.0 or less.

Examples of the photoacid generator (B) include compounds (onium salts) represented by "M ⁺ X ^- ", and are preferably compounds that generate an organic acid upon exposure to light.
Examples of the organic acid include sulfonic acids (aliphatic sulfonic acids, aromatic sulfonic acids, camphorsulfonic acids, etc.), carboxylic acids (aliphatic carboxylic acids, aromatic carboxylic acids, aralkyl carboxylic acids, etc.), carbonylsulfonylimide acids, bis(alkylsulfonyl)imide acids, and tris(alkylsulfonyl)methide acids.

In the compound represented by "M ⁺ X ^- ", M ⁺ represents an organic cation. The organic cation is a cation represented by formula (ZaI) (hereinafter also referred to as "cation (ZaI)").
), or a cation represented by formula (ZaII) (hereinafter also referred to as "cation (ZaII)") is preferred.

In formula (ZaI), R ²⁰¹ , R ²⁰² and R ²⁰³ each independently represent an organic group.
The number of carbon atoms in the organic groups of R ²⁰¹ , R ²⁰² , and R ²⁰³ is preferably 1 to 30, and more preferably 1 to 20. Any two of R ²⁰¹ to R ²⁰³ may be bonded to form a ring structure, and the ring may contain an oxygen atom, a sulfur atom, an ester group, an amide group, or a carbonyl group. Examples of groups formed by bonding any two of R ²⁰¹ to R ²⁰³ include alkylene groups (e.g., butylene and pentylene groups) and -CH ₂ -CH ₂ -O-CH ₂ -CH ₂ -.

The organic group of R ²⁰¹ , R ²⁰² , and R ²⁰³ is preferably an alkyl group, a cycloalkyl group, an aryl group, or a heteroaryl group.
The alkyl group may be either linear or branched. The number of carbon atoms in the alkyl group is not particularly limited, but is preferably 1 to 10, and more preferably 1 to 5. Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a t-butyl group.
The number of carbon atoms in the cycloalkyl group is not particularly limited, but is preferably 3 to 20, and more preferably 5 to 15. As the cycloalkyl group, monocyclic cycloalkyl groups such as a cyclopentyl group and a cyclohexyl group, and polycyclic cycloalkyl groups such as a norbornyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, and an adamantyl group are preferred.
The aryl group is preferably an aryl group having 6 to 20 carbon atoms, more preferably an aryl group having 6 to 15 carbon atoms, further preferably a phenyl group or naphthyl group, and particularly preferably a phenyl group.
The heteroaryl group is preferably a heteroaryl group having 3 to 20 carbon atoms. The heteroaryl group preferably contains at least one heteroatom selected from the group consisting of an oxygen atom, a sulfur atom, and a nitrogen atom. Examples of the heteroaryl group include a pyrrole residue, a furan residue, a thiophene residue, an indole residue, a benzofuran residue, and a benzothiophene residue.

In formula (ZaII), R ²⁰⁴ and R ²⁰⁵ each independently represent an aryl group, an alkyl group or a cycloalkyl group.
The aryl group of R ²⁰⁴ and R ²⁰⁵ is preferably a phenyl group or a naphthyl group, more preferably a phenyl group. The aryl group of R ²⁰⁴ and R ²⁰⁵ may be an aryl group having a heterocycle with an oxygen atom, a nitrogen atom, or a sulfur atom. Examples of the skeleton of the aryl group having a heterocycle include pyrrole, furan, thiophene, indole, benzofuran, and benzothiophene.
The alkyl group and cycloalkyl group of R ²⁰⁴ and R ²⁰⁵ are preferably a linear alkyl group having 1 to 10 carbon atoms or a branched alkyl group having 3 to 10 carbon atoms (e.g., a methyl group, an ethyl group, a propyl group, a butyl group, or a pentyl group), or a cycloalkyl group having 3 to 10 carbon atoms (e.g., a cyclopentyl group, a cyclohexyl group, or a norbornyl group).

The aryl group, alkyl group, and cycloalkyl group of R ²⁰⁴ and R ²⁰⁵ may each independently have a substituent. Examples of the substituent that the aryl group, alkyl group, and cycloalkyl group of R ²⁰⁴ and R ²⁰⁵ may have include an alkyl group (e.g., having 1 to 15 carbon atoms), a cycloalkyl group (e.g., having 3 to 15 carbon atoms), an aryl group (e.g., having 6 to 15 carbon atoms), an alkoxy group (e.g., having 1 to 15 carbon atoms), a halogen atom, a hydroxyl group, and a phenylthio group. It is also preferable that the substituents of R ²⁰⁴ and R ²⁰⁵ each independently form an acid-decomposable group by any combination of the substituents.

In the compound represented by "M ⁺ X ^- ", X ^- represents an organic anion.
The organic anion is not particularly limited, and examples thereof include monovalent or divalent or higher organic anions.
As the organic anion, anions having a significantly low ability to cause a nucleophilic reaction are preferred, and non-nucleophilic anions are more preferred.

Examples of non-nucleophilic anions include sulfonate anions (aliphatic sulfonate anions, aromatic sulfonate anions, camphorsulfonate anions, etc.), carboxylate anions (aliphatic carboxylate anions, aromatic carboxylate anions, aralkyl carboxylate anions, etc.), sulfonylimide anions, bis(alkylsulfonyl)imide anions, and tris(alkylsulfonyl)methide anions.

The aliphatic moiety in the aliphatic sulfonate anion and the aliphatic carboxylate anion may be a linear or branched alkyl group or a cycloalkyl group, and is preferably a linear or branched alkyl group having 1 to 30 carbon atoms or a cycloalkyl group having 3 to 30 carbon atoms.
The alkyl group may be, for example, a fluoroalkyl group (which may have a substituent other than a fluorine atom, or may be a perfluoroalkyl group).

The aryl group in the aromatic sulfonate anion and aromatic carboxylate anion is preferably an aryl group having 6 to 14 carbon atoms, such as a phenyl group, a tolyl group, and a naphthyl group.

The alkyl group, cycloalkyl group, and aryl group listed above may have a substituent. The substituent is not particularly limited, but examples include a nitro group, a halogen atom such as a fluorine atom or a chlorine atom, a carboxyl group, a hydroxyl group, an amino group, a cyano group, an alkoxy group (preferably having 1 to 15 carbon atoms), an alkyl group (preferably having 1 to 10 carbon atoms), a cycloalkyl group (preferably having 3 to 15 carbon atoms), an aryl group (preferably having 6 to 14 carbon atoms), an alkoxycarbonyl group (preferably having 2 to 7 carbon atoms), an acyl group (preferably having 2 to 12 carbon atoms), an alkoxycarbonyloxy group (preferably having 2 to 7 carbon atoms), an alkylthio group (preferably having 1 to 15 carbon atoms), an alkylsulfonyl group (preferably having 1 to 15 carbon atoms), an alkyliminosulfonyl group (preferably having 1 to 15 carbon atoms), and an aryloxysulfonyl group (preferably having 6 to 20 carbon atoms).

The aralkyl group in the aralkyl carboxylate anion is preferably an aralkyl group having 7 to 14 carbon atoms.
Examples of the aralkyl group having 7 to 14 carbon atoms include a benzyl group, a phenethyl group, a naphthylmethyl group, a naphthylethyl group, and a naphthylbutyl group.

An example of a sulfonylimide anion is the saccharin anion.

The alkyl group in the bis(alkylsulfonyl)imide anion and the tris(alkylsulfonyl)methide anion is preferably an alkyl group having 1 to 5 carbon atoms. Examples of the substituent on these alkyl groups include a halogen atom, an alkyl group substituted with a halogen atom, an alkoxy group, an alkylthio group, an alkyloxysulfonyl group, an aryloxysulfonyl group, and a cycloalkylaryloxysulfonyl group, and a fluorine atom or an alkyl group substituted with a fluorine atom is preferred.
In addition, the alkyl groups in the bis(alkylsulfonyl)imide anion may be bonded to each other to form a ring structure, which increases the acid strength.

Other non-nucleophilic anions include, for example, phosphorus fluorides (eg, PF ₆ ⁻ ), boron fluorides (eg, BF ₄ ⁻ ), and antimony fluorides (eg, SbF ₆ ⁻ ).

Preferred non-nucleophilic anions are aliphatic sulfonate anions in which at least the α-position of the sulfonic acid is substituted with a fluorine atom, aromatic sulfonate anions substituted with a fluorine atom or a group having a fluorine atom, bis(alkylsulfonyl)imide anions in which an alkyl group is substituted with a fluorine atom, or tris(alkylsulfonyl)methide anions in which an alkyl group is substituted with a fluorine atom. Among these, perfluoroaliphatic sulfonate anions (preferably having 4 to 8 carbon atoms) or benzenesulfonate anions having fluorine atoms are more preferable, and nonafluorobutanesulfonate anions, perfluorooctanesulfonate anions, pentafluorobenzenesulfonate anions, or 3,5-bis(trifluoromethyl)benzenesulfonate anions are even more preferable.

For the compound represented by "M ⁺ X ^- ", the contents of paragraphs [0114] to [0144] of JP-A No. 2005-2236 can be cited.

The photoacid generator (B) may be at least one selected from the group consisting of the following compounds (I) to (II):

(Compound (I))
Compound (I) is a compound having one or more structural moieties X and one or more structural moieties Y, which generates an acid containing a first acidic moiety derived from the structural moiety X and a second acidic moiety derived from the structural moiety Y when irradiated with actinic rays or radiation:
Structural moiety X: a structural moiety consisting of an anionic moiety A ₁ ^- and a cationic moiety M ₁ ⁺ , which forms a first acidic moiety represented by HA ₁ when irradiated with actinic rays or radiation. Structural moiety Y: a structural moiety consisting of an anionic moiety A ₂ ^- and a cationic moiety M ₂ ⁺ , which forms a second acidic moiety represented by HA ₂ when irradiated with actinic rays or radiation. The compound (I) satisfies the following condition I.

Condition I: Compound PI, which is obtained by replacing the cationic moiety M ₁ ⁺ in the structural moiety X and the cationic moiety M ₂ ⁺ in the structural moiety Y in the compound (I) with H ⁺ , has an acid dissociation constant a1 derived from the acidic moiety represented by HA ₁ , which is obtained by replacing the cationic moiety M ₁ ⁺ in the structural moiety X with H ⁺ , and an acid dissociation constant a2 derived from the acidic moiety represented by HA ₂ , which is obtained by replacing the cationic moiety M ₂ ⁺ in the structural moiety Y with H ⁺ , and the acid dissociation constant a2 is greater than the acid dissociation constant a1. At least one of the acid dissociation constants a1 is less than 0.

Condition I will be explained in more detail below.
When compound (I) is, for example, a compound that generates an acid having one of the first acidic site derived from the structural moiety X and one of the second acidic site derived from the structural moiety Y, compound PI corresponds to a "compound having HA ₁ and HA _2. "
More specifically, the acid dissociation constant a1 and the acid dissociation constant a2 of compound PI are calculated as follows: when compound PI becomes a "compound having A ₁ ^- and HA ₂ ", the pKa is the acid dissociation constant a1; and when the "compound having A ₁ ^- and HA ₂ " becomes a "compound having A ₁ ^- and A ₂ ^- ", the pKa is the acid dissociation constant a2.

When compound (I) is, for example, a compound that generates an acid having two of the first acidic sites derived from the structural moiety X and one of the second acidic sites derived from the structural moiety Y, compound PI corresponds to a "compound having two HA ₁ 's and one HA _2. "
When the acid dissociation constant of the compound PI is determined, the acid dissociation constant when the compound PI becomes "a compound having one A ₁ ^- , one HA ₁ and one HA ₂ " and the acid dissociation constant when the "compound having one A ₁ ^- , one HA ₁ and one HA ₂ " becomes "a compound having two A ₁ ^- and one HA ₂ " correspond to the above-mentioned acid dissociation constant a1. The acid dissociation constant when the "compound having two A ₁ ^- and one HA ₂ " becomes "a compound having two A ₁ ^- and A ₂ ^- " corresponds to the acid dissociation constant a2. That is, in the case of the compound PI, when the compound has a plurality of acid dissociation constants derived from the acidic site represented by HA ₁ obtained by replacing the cationic site M ₁ ⁺ in the structural site X with H ⁺ , the value of the acid dissociation constant a2 is larger than the largest value of the plurality of acid dissociation constants a1. In addition, when the acid dissociation constant when compound PI becomes "a compound having one A ₁ ^- , one HA ₁ , and one HA ₂ " is aa, and the acid dissociation constant when "a compound having one A ₁ ^- , one HA ₁ , and one HA ₂ " becomes "a compound having two A ₁ ^- and one HA ₂ " is ab, the relationship between aa and ab satisfies aa < ab.

The acid dissociation constant a1 and the acid dissociation constant a2 are determined by the above-mentioned method for measuring an acid dissociation constant.
The compound PI corresponds to an acid generated when compound (I) is irradiated with actinic rays or radiation.
When compound (I) has two or more structural moieties X, the structural moieties X may be the same or different from each other. In addition, the two or more A ₁ ⁻ and the two or more M ₁ ⁺ may be the same or different from each other.
In compound (I), A ₁ ^- and A ₂ ^- , as well as M ₁ ⁺ and M ₂ ⁺ may be the same or different, but it is preferable that A ₁ ^- and A ₂ ^- are different.

(Compound (II))
Compound (II) is a compound having two or more of the above structural moieties X and one or more of the following structural moieties Z, and is a compound that generates an acid containing two or more of the first acidic moieties derived from the structural moiety X and the structural moiety Z when irradiated with actinic rays or radiation.
Structural moiety Z: a non-ionic moiety capable of neutralizing an acid

When compound (II) is, for example, a compound that generates an acid having two of the first acidic sites derived from the structural site X and the structural site Z, compound PII corresponds to a "compound having two HA _1s ." When the acid dissociation constant of this compound PII is determined, the acid dissociation constant when compound PII becomes a "compound having one A ₁ ^- and one HA ₁ " and the acid dissociation constant when the "compound having one A ₁ ^- and one HA ₁ " becomes a "compound having two A ₁ ^-s " correspond to the acid dissociation constant a1.

The acid dissociation constants a1 are determined by the above-mentioned method for measuring an acid dissociation constant. At least one of the acid dissociation constants a1 is less than 0.
The compound PII corresponds to an acid generated when compound (II) is irradiated with actinic rays or radiation.
The two or more structural moieties X may be the same or different, and the two or more A ₁ ⁻ and the two or more M ₁ ⁺ may be the same or different.

The nonionic moiety capable of neutralizing an acid in the structural moiety Z is not particularly limited, and is preferably, for example, a moiety containing a group capable of electrostatically interacting with a proton, or a functional group having an electron.
Examples of the group capable of electrostatically interacting with a proton or the functional group having electrons include a functional group having a macrocyclic structure such as a cyclic polyether, or a functional group having a nitrogen atom having an unshared electron pair that does not contribute to π-conjugation. The nitrogen atom having an unshared electron pair that does not contribute to π-conjugation is, for example, a nitrogen atom having a partial structure shown in the following formula:

Examples of partial structures of functional groups having groups or electrons that can electrostatically interact with protons include crown ether structures, azacrown ether structures, primary to tertiary amine structures, pyridine structures, imidazole structures, and pyrazine structures, with primary to tertiary amine structures being preferred.

For the cation, compound (I) and compound (II), the contents of paragraphs [0207] to [0278] of WO 2022/024928 may be cited.

The content of the photoacid generator (B) in the composition of the present invention is preferably 1.0 mass% or more, more preferably 3.0 mass% or more, and even more preferably 5.0 mass% or more, based on the total solid content of the composition of the present invention. The content of the photoacid generator (B) is preferably 30.0 mass% or less, more preferably 25.0 mass% or less, and even more preferably 20.0 mass% or less, based on the total solid content of the composition of the present invention.
The photoacid generator (B) may be used alone or in combination of two or more. When two or more types are used, the total content is preferably within the above-mentioned suitable content range.

[Acid Diffusion Controller (C)]
The acid diffusion controller (C) traps the acid generated, for example, from the photoacid generator (B) during exposure, and acts as a quencher that suppresses the reaction of the acid-decomposable resin in unexposed areas caused by excess acid generated.
The type of the acid diffusion controller (C) is not particularly limited, and examples thereof include a basic compound (CA), a low molecular weight compound (CB) having a nitrogen atom and a group that is eliminated by the action of an acid, and a compound (CC) whose acid diffusion control ability is reduced or lost by irradiation with actinic rays or radiation.
Examples of the compound (CC) include an onium salt compound (CD) of an acid that is weaker than the acid generated from the photoacid generator (B) or the like, and a basic compound (CE) whose basicity is reduced or lost by irradiation with actinic rays or radiation.
Specific examples of the basic compound (CA) include those described in paragraphs [0132] to [0136] of WO 2020/066824. Specific examples of the basic compound (CE) whose basicity is reduced or eliminated by irradiation with actinic rays or radiation include those described in paragraphs [0137] to [0155] of WO 2020/066824 and those described in paragraph [0164] of WO 2020/066824. Specific examples of the low molecular weight compound (CB) having a nitrogen atom and a group that is eliminated by the action of an acid include those described in paragraphs [0156] to [0163] of WO 2020/066824.
For example, specific examples of the onium salt compound (CD) that is a relatively weak acid relative to the acid generated from the photoacid generator (B) or the like include those described in paragraphs [0305] to [0314] of WO 2020/158337.

In addition to the above, for example, known compounds disclosed in U.S. Patent Application Publication No. 2016/0070167A1, paragraphs [0627] to [0664], U.S. Patent Application Publication No. 2015/0004544A1, paragraphs [0095] to [0187], U.S. Patent Application Publication No. 2016/0237190A1, paragraphs [0403] to [0423], and U.S. Patent Application Publication No. 2016/0274458A1, paragraphs [0259] to [0328] can be suitably used as acid diffusion control agents.

When the composition of the present invention contains an acid diffusion controller, the content of the acid diffusion controller (the total content when a plurality of types are present) is preferably 0.1 to 15.0 mass %, and more preferably 1.0 to 15.0 mass %, based on the total solid content of the composition of the present invention.
In the composition of the present invention, the acid diffusion controller may be used alone or in combination of two or more kinds.

[Hydrophobic resin (resin (D))]
The composition of the present invention may further contain a hydrophobic resin (also referred to as "resin (D)") different from resin (A).
The hydrophobic resin is preferably designed to be unevenly distributed on the surface of the resist film, but unlike a surfactant, it does not necessarily have to have a hydrophilic group in the molecule, and does not necessarily have to contribute to uniform mixing of polar and non-polar substances.

From the viewpoint of uneven distribution on the surface layer of the film, the hydrophobic resin preferably has at least one of fluorine atoms, silicon atoms, and _CH3 partial structures contained in the side chain portion of the resin, more preferably has at least two of them. The hydrophobic resin preferably has a hydrocarbon group having 5 or more carbon atoms. These groups may be present in the main chain of the resin or may be substituted on the side chain.
Examples of hydrophobic resins include the compounds described in paragraphs [0275] to [0279] of WO 2020/004306.

When the composition of the present invention contains a hydrophobic resin, the content of the hydrophobic resin is preferably from 0.01 to 20.0 mass %, more preferably from 0.1 to 15.0 mass %, based on the total solid content of the composition of the present invention.
The hydrophobic resin may be used alone or in combination of two or more. When two or more types are used, the total content is preferably within the above-mentioned preferred content range.

[Surfactant]
The composition of the present invention may contain a surfactant. When the composition contains a surfactant, a pattern having better adhesion and fewer development defects can be formed.
The surfactant is preferably a fluorine-based and/or silicon-based surfactant.
Examples of fluorine-based and/or silicone-based surfactants include the surfactants disclosed in paragraphs [0218] and [0219] of WO 2018/193954.

When the composition of the present invention contains a surfactant, the content of the surfactant is preferably from 0.0001 to 2.0 mass%, more preferably from 0.0005 to 1.0 mass%, and still more preferably from 0.1 to 1.0 mass%, based on the total solid content of the composition of the present invention.
The surfactant may be used alone or in combination of two or more. When two or more surfactants are used, the total content is preferably within the above-mentioned preferred content range.

[Solvent (S)]
The composition of the present invention preferably contains a solvent.
The solvent preferably contains (M1) propylene glycol monoalkyl ether carboxylate and (M2) at least one selected from the group consisting of propylene glycol monoalkyl ether, lactate ester, acetate ester, alkoxypropionate ester, linear ketone, cyclic ketone, lactone, and alkylene carbonate. The solvent may further contain components other than the components (M1) and (M2).

The combination of the above-mentioned solvent and the above-mentioned resin is preferable from the viewpoint of improving the coatability of the composition of the present invention and reducing the number of development defects of the pattern. The above-mentioned solvent has a good balance of the solubility, boiling point, and viscosity of the above-mentioned resin, so that it is possible to suppress unevenness in the thickness of the resist film and the occurrence of precipitates during spin coating.
Details of the components (M1) and (M2) are described in paragraphs [0218] to [0226] of WO 2020/004306, the contents of which are incorporated herein by reference.

If the solvent further contains components other than components (M1) and (M2), the content of the components other than components (M1) and (M2) is preferably 5 to 30 mass % based on the total amount of the solvent.

The content of the solvent in the composition of the present invention is preferably determined so that the solids concentration is 0.5 to 30 mass %, and more preferably 1 to 20 mass %. This further improves the applicability of the composition of the present invention.

[Other additives]
The composition of the present invention may further contain a dissolution inhibiting compound, a dye, a plasticizer, a photosensitizer, a light absorber, and/or a compound that promotes solubility in a developer (for example, a phenol compound having a molecular weight of 1000 or less, or an alicyclic or aliphatic compound containing a carboxyl group).

The above-mentioned "dissolution-blocking compound" is a compound with a molecular weight of 3000 or less that decomposes under the action of acid and reduces its solubility in an organic developer.

[Actinic ray- or radiation-sensitive film, pattern formation method]
The present invention also relates to an actinic ray- or radiation-sensitive film formed from the composition of the present invention. The actinic ray- or radiation-sensitive film of the present invention is preferably a resist film.
The present invention also relates to a pattern forming method. The pattern forming method of the present invention is preferably a pattern forming method comprising the steps of forming an actinic ray-sensitive or radiation-sensitive film (typically a resist film) on a substrate using the composition of the present invention, exposing the actinic ray-sensitive or radiation-sensitive film, and developing the exposed actinic ray-sensitive or radiation-sensitive film using a developer.
The procedure for the pattern formation method using the composition of the present invention is not particularly limited, but it is preferable that the method comprises the following steps.
Step 1: forming an actinic ray-sensitive or radiation-sensitive film on a substrate using the composition of the present invention; Step 2: exposing the actinic ray-sensitive or radiation-sensitive film; Step 3: developing the exposed actinic ray-sensitive or radiation-sensitive film with a developer. The procedure of each of the above steps will be described in detail below.

(Step 1: Actinic ray-sensitive or radiation-sensitive film formation step)
Step 1 is a step of forming an actinic ray- or radiation-sensitive film on a substrate using the composition of the present invention.

An example of a method for forming an actinic ray- or radiation-sensitive film on a substrate using the composition of the present invention is a method in which the composition of the present invention is applied onto a substrate.
The composition of the present invention is preferably filtered as necessary before application. The pore size of the filter is preferably 0.1 μm or less, more preferably 0.05 μm or less, and even more preferably 0.03 μm or less. The filter is preferably made of polytetrafluoroethylene, polyethylene, or nylon.

The composition of the present invention can be applied by a suitable application method such as a spinner or coater onto a substrate (e.g., silicon, silicon dioxide-coated) such as those used in the manufacture of integrated circuit elements. The application method is preferably spin coating using a spinner. The rotation speed when spin coating using a spinner is preferably 1000 to 3000 rpm (rotations per minute).
After coating the composition of the present invention, the substrate may be dried to form an actinic ray-sensitive or radiation-sensitive film. If necessary, various undercoats (inorganic films, organic films, anti-reflection films) may be formed under the actinic ray-sensitive or radiation-sensitive film.

The drying method may be, for example, a method of drying by heating. Heating can be performed by a means provided in a normal exposure machine and/or a developing machine, and may also be performed using a hot plate or the like. The heating temperature is preferably 80 to 150°C, more preferably 80 to 140°C, and even more preferably 80 to 130°C. The heating time is preferably 30 to 1000 seconds, more preferably 60 to 800 seconds, and even more preferably 60 to 600 seconds.

The thickness of the actinic ray-sensitive or radiation-sensitive film is not particularly limited, but is preferably 10 to 120 nm, since it allows for the formation of fine patterns with higher precision. In particular, when EUV exposure is used, the thickness of the actinic ray-sensitive or radiation-sensitive film is more preferably 10 to 65 nm, and even more preferably 15 to 50 nm. When ArF immersion exposure is used, the thickness of the resist film is more preferably 10 to 120 nm, and even more preferably 15 to 90 nm.

A top coat may be formed on the actinic ray-sensitive or radiation-sensitive film by using a top coat composition.
It is preferable that the top coat composition does not mix with the actinic ray-sensitive or radiation-sensitive film, and can be uniformly applied on the actinic ray-sensitive or radiation-sensitive film. The top coat is not particularly limited, and a conventionally known top coat can be formed by a conventionally known method, for example, a top coat can be formed based on the description in paragraphs [0072] to [0082] of JP2014-059543A.
For example, it is preferable to form a top coat containing a basic compound such as that described in JP 2013-61648 A on an actinic ray-sensitive or radiation-sensitive film. Specific examples of the basic compound that the top coat may contain include the basic compounds that may be contained in the composition of the present invention.
It is also preferred that the top coat contains a compound containing at least one group or bond selected from the group consisting of an ether bond, a thioether bond, a hydroxyl group, a thiol group, a carbonyl bond, and an ester bond.

(Step 2: Exposure step)
Step 2 is a step of exposing the actinic ray- or radiation-sensitive film to light.
The exposure method may be a method in which the formed actinic ray-sensitive or radiation-sensitive film is irradiated with actinic rays or radiation through a predetermined mask.
Examples of the actinic ray or radiation include infrared light, visible light, ultraviolet light, far ultraviolet light, extreme ultraviolet light, X-rays, and electron beams, preferably 250 nm or less, more preferably 220 nm or less, and particularly preferably far ultraviolet light having a wavelength of 1 to 200 nm, specifically KrF excimer laser (248 nm), ArF excimer laser (193 nm), _F2 excimer laser (157 nm), EUV (13.5 nm), X-rays, and electron beams.

After exposure, it is preferable to perform baking (heating) before development, which promotes the reaction of the exposed area and improves the sensitivity and pattern shape.
The heating temperature is preferably from 80 to 150°C, more preferably from 80 to 140°C, and even more preferably from 80 to 130°C.
The heating time is preferably from 10 to 1,000 seconds, more preferably from 10 to 180 seconds, and even more preferably from 30 to 120 seconds.
Heating can be carried out by a means provided in a normal exposure machine and/or developing machine, and may be carried out using a hot plate or the like.
This step is also called post-exposure bake.

(Process 3: Development process)
Step 3 is a step of developing the exposed actinic ray- or radiation-sensitive film with a developer to form a pattern.
The developer may be an alkaline developer or a developer containing an organic solvent (hereinafter, also referred to as an organic developer).

Examples of the developing method include a method of immersing a substrate in a tank filled with a developing solution for a certain period of time (dip method), a method of piling up the developing solution on the substrate surface by surface tension and leaving it to stand for a certain period of time to develop (paddle method), a method of spraying the developing solution on the substrate surface (spray method), and a method of continuously discharging the developing solution while scanning a developing solution discharge nozzle at a constant speed onto a substrate rotating at a constant speed (dynamic dispense method).
After the development step, a step of stopping the development while replacing the solvent with another solvent may be carried out.
The development time is not particularly limited as long as the resin in the unexposed area is sufficiently dissolved, and is preferably from 10 to 300 seconds, more preferably from 20 to 120 seconds.
The temperature of the developer is preferably from 0 to 50°C, and more preferably from 15 to 35°C.

The alkaline developer is preferably an aqueous alkaline solution containing an alkali. There are no particular limitations on the type of the aqueous alkaline solution, but examples include an aqueous alkaline solution containing a quaternary ammonium salt such as tetramethylammonium hydroxide, an inorganic alkali, a primary amine, a secondary amine, a tertiary amine, an alcohol amine, or a cyclic amine. Of these, the alkaline developer is preferably an aqueous solution of a quaternary ammonium salt such as tetramethylammonium hydroxide (TMAH). Appropriate amounts of alcohols, surfactants, etc. may be added to the alkaline developer. The alkaline concentration of the alkaline developer is preferably 0.1 to 20% by mass. The pH of the alkaline developer is preferably 10.0 to 15.0.

The organic developer is preferably a developer containing at least one organic solvent selected from the group consisting of ketone solvents, ester solvents, alcohol solvents, amide solvents, ether solvents, and hydrocarbon solvents.

The above-mentioned solvents may be mixed in combination, or may be mixed with a solvent other than the above or with water. The water content of the developer as a whole is preferably less than 50% by mass, more preferably less than 20% by mass, even more preferably less than 10% by mass, and particularly preferably substantially free of water.
The content of the organic solvent in the organic developer is preferably 50% by mass or more and 100% by mass or less, more preferably 80% by mass or more and 100% by mass or less, still more preferably 90% by mass or more and 100% by mass or less, and particularly preferably 95% by mass or more and 100% by mass or less, based on the total amount of the developer.

(Other processes)
The above pattern formation method preferably includes, after step 3, a step of washing with a rinsing liquid.

The rinse liquid used in the rinse step following the step of developing with an alkaline developer is, for example, pure water, to which an appropriate amount of a surfactant may be added.
A suitable amount of a surfactant may be added to the rinse solution.

The rinse liquid used in the rinse step following the development step using an organic developer is not particularly limited as long as it does not dissolve the pattern, and a solution containing a general organic solvent can be used. It is preferable to use a rinse liquid containing at least one organic solvent selected from the group consisting of hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents, amide solvents, and ether solvents.

The method of the rinsing step is not particularly limited, and examples thereof include a method of continuously discharging a rinsing liquid onto a substrate rotating at a constant speed (spin coating method), a method of immersing a substrate in a tank filled with the rinsing liquid for a certain period of time (dip method), and a method of spraying the rinsing liquid onto the substrate surface (spray method).
The pattern forming method may also include a heating step (Post Bake) after the rinsing step. This step removes the developer and rinsing solution remaining between the patterns and inside the pattern due to baking. This step also has the effect of annealing the resist pattern and improving the surface roughness of the pattern. The heating step after the rinsing step is usually performed at 40 to 250°C (preferably 90 to 200°C) for usually 10 seconds to 3 minutes (preferably 30 seconds to 120 seconds).

Furthermore, the formed pattern may be used as a mask to perform an etching process on the substrate. That is, the pattern formed in step 3 may be used as a mask to process the substrate (or the underlayer film and the substrate) to form a pattern on the substrate.
Although the method for processing the substrate (or the underlayer film and the substrate) is not particularly limited, a method is preferred in which the substrate (or the underlayer film and the substrate) is dry-etched using the pattern formed in step 3 as a mask to form a pattern on the substrate. The dry etching is preferably oxygen plasma etching.

The composition of the present invention and various materials used in the pattern formation method (e.g., solvent, developer, rinse, anti-reflective film forming composition, top coat forming composition, etc.) preferably do not contain impurities such as metals. The content of impurities contained in these materials is preferably 1 mass ppm (parts per million) or less, more preferably 10 mass ppb (parts per billion) or less, even more preferably 100 mass ppt (parts per trillion) or less, particularly preferably 10 mass ppt or less, and most preferably 1 mass ppt or less. There is no particular lower limit, and 0 mass ppt or more is preferable. Here, examples of metal impurities include Na, K, Ca, Fe, Cu, Mg, Al, Li, Cr, Ni, Sn, Ag, As, Au, Ba, Cd, Co, Pb, Ti, V, W, and Zn.

An example of a method for removing impurities such as metals from various materials is filtration using a filter. Details of filtration using a filter are described in paragraph [0321] of WO 2020/004306.

Methods for reducing metal and other impurities contained in various materials include, for example, selecting raw materials with low metal content as the raw materials that make up the various materials, filtering the raw materials that make up the various materials, and performing distillation under conditions that minimize contamination as much as possible, such as lining the inside of the equipment with Teflon (registered trademark).

In addition to filtration, impurities may be removed using an adsorbent, or a combination of filtration and an adsorbent may be used. As the adsorbent, known adsorbents can be used, for example, inorganic adsorbents such as silica gel and zeolite, and organic adsorbents such as activated carbon. In order to reduce impurities such as metals contained in the various materials described above, it is necessary to prevent the incorporation of metal impurities during the manufacturing process. Whether metal impurities have been sufficiently removed from the manufacturing equipment can be confirmed by measuring the content of metal components contained in the cleaning solution used to clean the manufacturing equipment. The content of metal components contained in the cleaning solution after use is preferably 100 ppt by mass or less, more preferably 10 ppt by mass or less, and even more preferably 1 ppt by mass or less. There is no particular lower limit, and 0 ppt by mass or more is preferable.

An organic processing liquid such as a rinse liquid may contain a conductive compound to prevent breakdown of chemical liquid piping and various parts (filters, O-rings, tubes, etc.) due to static charging and subsequent static discharge. The conductive compound is not particularly limited, but an example thereof is methanol. The amount added is not particularly limited, but from the viewpoint of maintaining favorable development characteristics or rinsing characteristics, it is preferably 10% by mass or less, and more preferably 5% by mass or less. There is no particular lower limit, and 0.01% by mass or more is preferable.
The chemical liquid piping may be made of, for example, stainless steel (SUS), or various piping coated with antistatic polyethylene, polypropylene, or fluororesin (polytetrafluoroethylene, perfluoroalkoxy resin, etc.). Similarly, the filter and O-ring may be made of antistatic polyethylene, polypropylene, or fluororesin (polytetrafluoroethylene, perfluoroalkoxy resin, etc.).

[Electronic device manufacturing method]
The present specification also relates to a method for manufacturing an electronic device, including the above-mentioned pattern formation method, and an electronic device manufactured by this manufacturing method.
Preferred embodiments of the electronic device of the present specification include those mounted in electric and electronic equipment (home appliances, OA (Office Automation), media-related equipment, optical equipment, communication equipment, and the like).

[resin]
The present invention also relates to a resin containing at least one type of repeating unit represented by the following general formula (1) and at least one type of repeating unit represented by the following general formula (2).

For details of the resin of the present invention, the above explanation of the resin (A) can be directly applied.
The content ratio of the repeating unit represented by the above general formula (2) to all repeating units in the above resin is preferably 30 to 60 mol %.
The weight average molecular weight of the resin is preferably 4,000 or more.
It is preferable that A ¹ in the above general formula (1) and A ² in the above general formula (2) are aromatic ring hydrocarbon groups.

[Method of producing resin]
The present invention also relates to a method for producing a resin by polymerizing at least two types of monomers in the presence of a nitroxide radical represented by the following general formula (N) and a radical polymerization initiator to produce a resin (X) containing at least two types of repeating units represented by the following general formula (3):

In general formula (3), R ₃₁ represents an organic group, a halogen atom, or a hydroxyl group. R ₃₂ represents a hydrogen atom, an organic group, or a halogen atom. R ₃₃ represents a hydrogen atom or an organic group. A ³ represents an aromatic hydrocarbon group, or an aromatic heterocyclic group. n3 represents an integer of 0 to 5. When n3 is an integer of 2 to 5, multiple R ₃₁ may be the same or different and may be bonded to form a ring. R ₃₃ and A ³ may be bonded to form a ring.
The groups in formula (3) will be described later.

The method for producing the above-mentioned resin (A) is not particularly limited, but it can be preferably produced by the resin production method of the present invention.
The resin production method of the present invention can also produce resins other than the resin (A).

The following describes the process for producing resin (X) containing at least two types of repeating units represented by general formula (3) (also referred to as process (1)).

[Step (1) (polymerization step)]
In the step (1) of the present invention, at least two kinds of monomers are polymerized in the presence of a nitroxide radical represented by the above general formula (N) and a radical polymerization initiator to obtain a nitroxide represented by the above general formula (1). This is a step of producing a resin (X) containing at least two kinds of repeating units.

<Monomer>
In the step (1), at least two kinds of monomers represented by the following general formula (3m) are used as raw material monomers for the repeating unit represented by the above general formula (3) in the resin (X).

In formula (3m), _R31 represents an organic group, a halogen atom, or a hydroxyl group, _R32 represents a hydrogen atom, an organic group, or a halogen atom, and _R33 represents a hydrogen atom or an organic group.
^A3 represents an aromatic hydrocarbon group or an aromatic heterocyclic group. n3 represents an integer of 0 to 5. When n3 is an integer of 2 to 5, multiple _R31 may be the same or different and may be bonded to form a ring. _R33 and ^A3 may be bonded to form a ring.

In formula (3m), R ₃₁ , R ₃₂ , R ₃₃ , A ³ and n3 have the same meanings as R ₃₁ , R ₃₂ , R ₃₃ , A ³ and n3 in formula (3), and preferred examples thereof are also the same.
The groups in formula (3) will be described later.

In step (1), a monomer other than the monomer represented by the above general formula (3m) may be used depending on the desired resin structure.

In the reaction of step (1), the monomers may be added to the reaction system all at once, but from the viewpoint of the degree of dispersion of the resulting resin (X) and safety, a multi-stage polymerization method in which the monomers are added in portions may also be used.

<Radical Polymerization Initiator>
The reaction in the above step (1) uses a radical polymerization initiator. As the radical polymerization initiator, for example, azo-based initiators and peroxides are used to initiate polymerization. As the radical initiator, azo-based initiators are preferred, and azo-based initiators having an ester group, a cyano group, or a carboxyl group are preferred. Preferred initiators include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), and dimethyl 2,2'-azobis(2-methylpropionate). If desired, the initiator may be added in multiple batches.

<Nitroxide radical>
The reaction in the above step (1) is carried out in the presence of a nitroxide radical represented by the following general formula (N).
The nitroxide radical used in the production method of the present invention is a compound that exists stably in the form of a free radical, and is a radical formed on an oxygen atom bonded to a nitrogen atom.

Examples of the organic group represented by _R1 include organic groups having 1 to 30 carbon atoms, preferably organic groups having 1 to 20 carbon atoms, and more preferably organic groups having 1 to 10 carbon atoms. The organic group represented by _R1 is not particularly limited, and examples thereof include an alkyl group and an aryl group.

The alkyl group is preferably an alkyl group having 1 to 6 carbon atoms.
The aryl group is preferably a phenyl group or naphthyl group having 6 to 10 carbon atoms.

The organic group represented by R ₁ may further have a substituent. Examples of the substituent include an alkyl group, an aryl group, an ester group, a hydroxyl group, a carbonyl group, a phosphate ester, and a carboxyalkyl group.

Two R ₁ may be bonded to form a ring. Examples of the ring formed by bonding two R ₁ include a piperidine ring and a pyrrolidine ring. A methylene group forming the ring may be substituted with a carbonyl group.
In a preferred embodiment, two or more nitroxide radicals represented by formula (N) may be bonded via a single bond or a linking group.

Specific examples of the nitroxide radical represented by the general formula (N) include 2,2,6,6-tetramethyl-1-piperidinyloxy radical (N-1 below), 2,2,6,6-tetraethyl-1-piperidinyloxy radical, 2,2,6,6-tetramethyl-4-oxo-1-pyrrolidinyloxy radical (N-2 below), 2,2,5,5-tetramethyl-1-pyrrolidinyloxy radical, 1,1,3,3-tetramethyl-2-isoindolinyloxy radical, N,N-di-t-butylamineoxy radical, etc. The 2,2,6,6-tetramethyl-1-piperidinyloxy radical (N-1 below) is preferably used in the present invention.
Further examples include compounds N-3 to N-9 described below.

The ratio of monomer to nitroxide radical is preferably 0.001 to 0.1 moles of nitroxide radical per mole of monomer, and more preferably 0.01 to 0.05 moles. When the ratio of the two is within the above range, the molecular weight and molecular weight distribution of the resin can be appropriately controlled, and the resin can be produced at an appropriate polymerization rate, which is preferable.

The ratio of the two to be used in combination is not particularly limited, but can be selected from the range of 0.1 to 2 moles, preferably 0.5 to 1.5 moles, and more preferably 0.8 to 1.2 moles of the radical polymerization initiator per mole of the nitroxide radical.
It is preferable that the nitroxide radical does not also function as a polymerization initiator. Specifically, it is preferable that the nitroxide radical does not combine with a polymerization initiator and function as a polymerization initiator as a whole.

When copolymerizing a styrene-like derivative with another styrene-like derivative to obtain a copolymer, conventional polymerization methods were unable to reduce the probability of a termination reaction occurring at the radical growing end of the polymer, making it difficult to increase the incorporation rate of a specific styrene-like derivative and to obtain a high molecular weight substance.

As a result of investigations conducted by the present inventors to solve the above problems, it was found that by performing radical polymerization via nitroxide radicals (NMP: Nitroxide Mediated Polymerization), the introduction rate of a specific styrene-like derivative is improved and a high molecular weight substance can be obtained.
Although the details of the mechanism are not clear, it is presumed that polymerization with NMP can reduce the probability of a termination reaction occurring at the radical growing end of the polymer, thereby improving the introduction rate of a specific styrene-like derivative and making it possible to obtain a high molecular weight substance.
Therefore, according to the production method of the present invention, it is possible to synthesize a copolymer that is versatile and has a wide range of applications.

<Solvent>
The reaction in the above step (1) is typically carried out in a liquid phase, i.e., the above reaction system typically further contains a solvent.
The solvent is not particularly limited as long as it dissolves each component, and examples thereof include alcohol solvents, alkylene glycol monoalkyl ether carboxylates, alkylene glycol monoalkyl ethers, cyclic lactones, linear or cyclic ketones, alkylene carbonates, alkyl carboxylates, alkyl alkoxyacetates, alkyl pyruvates, etc. Other usable solvents include, for example, the solvents described in U.S. Patent Application Publication No. 2008/0248425 A1, paragraphs [0244] and thereafter.

The alcohol-based solvent is not particularly limited as long as it contains -OH, but examples include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, ethylene glycol, propylene glycol, 2-methoxyethanol, 1-methoxy-2-propanol, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, diacetone alcohol, etc.

Preferred examples of alkylene glycol monoalkyl ether carboxylates include propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, propylene glycol monomethyl ether propionate, propylene glycol monoethyl ether propionate, ethylene glycol monomethyl ether acetate, and ethylene glycol monoethyl ether acetate.

Preferred examples of the alkylene glycol monoalkyl ether include propylene glycol monomethyl ether (1-methoxy-2-propanol), propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, ethylene glycol monomethyl ether, and ethylene glycol monoethyl ether.
Incidentally, alkylene glycol monoalkyl ethers are included in the alcohol solvents.

Preferred examples of the alkyl alkoxypropionate include ethyl 3-ethoxypropionate, methyl 3-methoxypropionate, methyl 3-ethoxypropionate, and ethyl 3-methoxypropionate.
Preferred examples of the cyclic lactone include β-propiolactone, β-butyrolactone, γ-butyrolactone, α-methyl-γ-butyrolactone, β-methyl-γ-butyrolactone, γ-valerolactone, γ-caprolactone, γ-octanoic lactone, and α-hydroxy-γ-butyrolactone.

Examples of chain or cyclic ketones include 2-butanone (methyl ethyl ketone), 3-methylbutanone, pinacolone, 2-pentanone, 3-pentanone, 3-methyl-2-pentanone, 4-methyl-2-pentanone, 2-methyl-3-pentanone, 4,4-dimethyl-2-pentanone, 2,4-dimethyl-3-pentanone, 2,2,4,4-tetramethyl-3-pentanone, 2-hexanone, 3-hexanone, 5-methyl-3-hexanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-methyl-3-heptanone, 5-methyl-3-heptanone, 2,6-dimethyl-4-heptanone, 2-octanone, 3-octanone, and 2-nonane. Preferred examples include nonanone, 3-nonanone, 5-nonanone, 2-decanone, 3-decanone, 4-decanone, 5-hexen-2-one, 3-penten-2-one, cyclopentanone, 2-methylcyclopentanone, 3-methylcyclopentanone, 2,2-dimethylcyclopentanone, 2,4,4-trimethylcyclopentanone, cyclohexanone, 3-methylcyclohexanone, 4-methylcyclohexanone, 4-ethylcyclohexanone, 2,2-dimethylcyclohexanone, 2,6-dimethylcyclohexanone, 2,2,6-trimethylcyclohexanone, cycloheptanone, 2-methylcycloheptanone, and 3-methylcycloheptanone.

Preferred examples of the alkylene carbonate include propylene carbonate, vinylene carbonate, ethylene carbonate, and butylene carbonate.
A preferred example of the alkyl carboxylate is butyl acetate.

Preferred examples of the alkoxy alkyl acetate include 2-methoxyethyl acetate, 2-ethoxyethyl acetate, 2-(2-ethoxyethoxy)ethyl acetate, 3-methoxy-3-methylbutyl acetate, and 1-methoxy-2-propyl acetate.
Preferred examples of the alkyl pyruvate include methyl pyruvate, ethyl pyruvate, and propyl pyruvate.

These solvents may be used alone or in combination of two or more.

The above polymerization reaction is preferably carried out in an inert gas atmosphere such as nitrogen or argon. If necessary, the polymerization may be carried out in the presence of a chain transfer agent (e.g., alkyl mercaptan, etc.).

The monomer concentration in the reaction system is preferably from 20 to 70% by mass, and more preferably from 25 to 50% by mass.
The reaction temperature is usually from 10°C to 150°C, preferably from 30°C to 120°C, and more preferably from 40°C to 100°C.
The reaction time is usually from 1 to 48 hours, preferably from 1 to 24 hours, and more preferably from 1 to 12 hours.

In a preferred embodiment, a solvent is used in the polymerization step, and the content of the alcohol-based solvent is preferably 20 mass % or more based on the total amount of the solvent.
The content of the alcohol solvent is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more, based on the total amount of the above solvents.

The alcohol solvent is preferably at least one selected from the group consisting of methanol, ethanol, 1-propanol, 2-propanol, ethylene glycol, propylene glycol, 2-methoxyethanol, 1-methoxy-2-propanol, methyl lactate, ethyl lactate, and diacetone alcohol.

<Resin (X)>
The resin (X) produced by the resin producing method of the present invention will be described below. The resin (X) contains at least two kinds of repeating units represented by the following general formula (3).

(Repeating unit represented by general formula (3))

In formula (3), R ₃₁ represents an organic group, a halogen atom, or a hydroxyl group.
The organic group represented by R ₃₁ is not particularly limited, but examples thereof include the organic groups exemplified above as the substituent T.
The organic group may, for example, be an organic group having 1 to 30 carbon atoms, preferably an organic group having 1 to 20 carbon atoms, and more preferably an organic group having 1 to 10 carbon atoms.
The organic group may have a heteroatom (for example, a nitrogen atom, an oxygen atom, a sulfur atom, a silicon atom, etc.).
The organic group represented by R ₃₁ may be the above-mentioned acid-decomposable group, and preferably has a structure in which a phenolic hydroxyl group or a carboxyl group is protected by a group that is eliminated by the action of an acid as described above. It is also preferably a group represented by any one of the general formulae (16) to (17) described later.
The organic group may also be a group that is decomposed by a base as R ₆₁ described below to generate an --OH group or a --COOH group (also referred to as a "base-decomposable group").
Examples of the halogen atom represented by R ₃₁ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

In formula (3), R ₃₂ represents a hydrogen atom, an organic group or a halogen atom.

Examples of the organic group represented by R ₃₂ include an alkyl group, a cycloalkyl group, an aryl group, an acyl group, and an alkylcarbonyloxy group.
The alkyl group may be linear or branched. The number of carbon atoms in the alkyl group is not particularly limited, but is preferably 1 to 10, and more preferably 1 to 3.
The cycloalkyl group may be either monocyclic or polycyclic, and preferably has 3 to 8 carbon atoms.
The aryl group is preferably an aryl group having 6 to 10 carbon atoms, such as a phenyl group.
The acyl group is preferably an acyl group having 1 to 20 carbon atoms.
The alkyl group in the alkylcarbonyloxy group may be linear or branched. The number of carbon atoms in the alkyl group is not particularly limited, but is preferably 1 to 10, and more preferably 1 to 3.

Examples of the halogen atom represented by R ₃₂ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

R ₃₃ represents a hydrogen atom or an organic group. Examples of the organic group represented by R ₃₃ include the same organic groups as those represented by R ₃₂ , and the preferred ranges are also the same.

In formula (3), ^A3 represents an aromatic hydrocarbon group or an aromatic heterocyclic group.
The aromatic hydrocarbon group represented by ^A3 may be, for example, an arylene group having 6 to 15 carbon atoms, and specific preferred examples thereof include a phenylene group, a naphthylene group, and an anthrylene group.
Examples of the aromatic heterocyclic group represented by ^A3 include heteroarylene groups having 2 to 15 carbon atoms, and include those having 5 to 10 members. Specific examples include groups in which any one hydrogen atom has been removed from a furyl group, a thienyl group, a thiazolyl group, a pyrrolyl group, an oxazolyl group, a pyridyl group, a benzofuranyl group, a benzothienyl group, a quinolinyl group, a carbazolyl group, and the like.

^A3 is preferably an aromatic hydrocarbon group, more preferably a phenylene group.

In general formula (3), n3 represents an integer from 0 to 5. It is preferable that n3 is 1 or 2.

<Resin (X1)>
In one preferred embodiment of the method for producing a resin of the present invention, the resin (X) contains at least one type of repeating unit represented by the following general formula (4) and at least one type of repeating unit represented by the following general formula (5). Hereinafter, this resin is also referred to as resin (X1).

When a styrene-like derivative in which the carbon atom in the main chain to which an aromatic ring group is bonded has a substituent (hereinafter also referred to as an α-substituted styrene-like derivative) is copolymerized with a styrene-like derivative in which the carbon atom in the main chain to which an aromatic ring group is bonded has no substituent (hereinafter also referred to as an α-unsubstituted styrene-like derivative), problems have arisen in that the steric hindrance of the α-substituted styrene-like derivative is large and the ceiling temperature is low, resulting in poor polymerizability, a low introduction rate of the α-substituted styrene-like derivative, and difficulty in obtaining a high molecular weight substance in ordinary radical polymerization.
Furthermore, homopolymers of α-substituted styrene-like derivatives can be synthesized by anionic polymerization or cationic polymerization, but have the problem of poor thermal stability, since the main chain is cleaved by heating.

As a result of investigations conducted by the present inventors to solve the above problems, it was found that by performing radical polymerization via a nitroxide radical (NMP: Nitroxide Mediated Polymerization), the introduction rate of an α-substituted styrene-like derivative can be improved and a high molecular weight product can be obtained.
Although the details of the mechanism are not clear, it is presumed that by carrying out polymerization with NMP, it is possible to suppress the probability of a termination reaction of the radical growing end of the polymer to a low level, and it is possible to proceed with alternating copolymerization of an α-unsubstituted styrene-like derivative and an α-substituted styrene derivative in the production of resin (X1), thereby improving the introduction rate of the α-substituted styrene-like derivative in particular and enabling the production of a high molecular weight substance.

In formula (4), R ₄₁ has the same meaning as R ₃₁ in formula (3).
The organic group represented by R ₄₁ may be the above-mentioned acid-decomposable group, and preferably has a structure in which a phenolic hydroxyl group or a carboxyl group is protected by a group that is eliminated by the action of an acid as described above. It is also preferably a group represented by any one of the general formulae (16) to (17) described later.
The organic group may also be a group that is decomposed by a base as R ₆₁ described below to generate an --OH group or a --COOH group (also referred to as a "base-decomposable group").
Examples of the halogen atom represented by R ₄₁ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, with a fluorine atom and a chlorine atom being preferred.

^A4 in formula (4) has the same meaning as ^A3 in formula (3), and preferred examples are also the same.
That is, ^A4 is preferably an aromatic hydrocarbon group, and more preferably a phenylene group.

n4 in general formula (4) has the same meaning as n3 in general formula (3), and preferred examples are also the same.

Specific examples of monomers corresponding to the repeating unit represented by general formula (4) include specific examples of monomers corresponding to the repeating unit represented by general formula (1) above.

The repeating unit represented by general formula (4) contained in resin (X1) may be of one type or of two or more types.

The content ratio of the repeating unit represented by general formula (4) to all repeating units in resin (X1) is not particularly limited, but can be, for example, 40 to 70 mol %.

In formula (5), R ₅₁ has the same meaning as R ₃₁ in formula (3).
The organic group represented by R ₅₁ may be the above-mentioned acid-decomposable group, and preferably has a structure in which a phenolic hydroxyl group or a carboxyl group is protected by a group that is eliminated by the action of an acid as described above. It is also preferably a group represented by any one of the general formulae (16) to (17) described below.
The organic group may also be a group that is decomposed by a base as R ₆₁ described below to generate an --OH group or a --COOH group (also referred to as a "base-decomposable group").
Examples of the halogen atom represented by R ₅₁ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, with a fluorine atom and a chlorine atom being preferred.

The organic group and halogen atom as R ₅₂ in the general formula (5) include the organic group and halogen atom as R ₁₂ in the general formula (1), and the preferred ranges are also the same.
R ₅₂ is preferably an alkyl group or a halogen atom, more preferably an alkyl group, and further preferably a methyl group.

^A5 in formula (5) has the same meaning as ^A3 in formula (3), and preferred examples thereof are also the same.
That is, ^A5 is preferably an aromatic hydrocarbon group, and more preferably a phenylene group.

In the resin (X1), ^A4 in the general formula (4) and ^A5 in the general formula (5) are preferably aromatic ring hydrocarbon groups.

n5 in general formula (5) has the same meaning as n3 in general formula (3), and preferred examples are also the same.

Specific examples of monomers corresponding to the repeating unit represented by general formula (5) include specific examples of monomers corresponding to the repeating unit represented by general formula (2) described above.

The repeating unit represented by general formula (5) contained in resin (X1) may be of one type or of two or more types.

The content ratio of the repeating unit represented by general formula (5) to all repeating units in resin (X1) is preferably 30 to 60 mol%, more preferably 40 to 55 mol%, and even more preferably 40 to 53 mol%.

Resin (X1) may have a repeating unit other than the repeating unit represented by the general formula (4) and the repeating unit represented by the general formula (5). Examples of the other repeating units include the repeating units having an acid-decomposable group described in the above resin (A) and other repeating units.

The above-mentioned resin (A) can be obtained by having an acid-decomposable group in any of the repeating units of the resin (X1), i.e., by using a monomer having an acid-decomposable group as the raw material monomer of the resin (X1).

In another preferred embodiment of the resin production method of the present invention, the resin (X) is produced via a resin (P1) containing at least one type of repeating unit represented by the following general formula (41) and at least one type of repeating unit represented by the following general formula (51).
The production process of resin (P1) is the same as "step (1)" which is the production process of resin (X1) described above.
If the resin (P1) is not subjected to any other step (other than step (1)) described below, the resin (P1) is the resin (X).

In general formula (41), R ₄₁₁ represents an organic group or a halogen atom. R ₄₂ represents a hydrogen atom or an organic group. A ⁴ represents an aromatic hydrocarbon group or an aromatic heterocyclic group. n4 represents an integer of 0 to 5. When n4 is an integer of 2 to 5, multiple R ₄₁₁ may be the same or different and may be bonded to form a ring. R ₄₂ and A ⁴ may be bonded to form a ring.
In general formula (51), R ₅₁₁ represents an organic group or a halogen atom. R ₅₂ represents an organic group or a halogen atom. A ⁵ represents an aromatic hydrocarbon group or an aromatic heterocyclic group. n5 represents an integer of 0 to 5. When n5 is an integer of 2 to 5, multiple R ₅₁₁ may be the same or different and may be bonded to form a ring.

In formula (41), the organic group of R ₄₁₁ has the same meaning as the organic group of R ₁₁ in formula (1).
The organic group represented by R ₄₁₁ may be the above-mentioned acid-decomposable group, and preferably has a structure in which a phenolic hydroxyl group or a carboxyl group is protected by a group that is eliminated by the action of an acid as described above. It is also preferably a group represented by any one of the general formulae (16) to (17) described later.
The organic group may also be a group that is decomposed by a base as R ₆₁ described below to generate an --OH group or a --COOH group (also referred to as a "base-decomposable group").
Examples of the halogen atom represented by R ₄₁₁ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom and a chlorine atom are preferable.

^A4 in formula (41) has the same meaning as ^A3 in formula (3), and preferred examples are also the same.
That is, ^A4 is preferably an aromatic hydrocarbon group, and more preferably a phenylene group.

n4 in general formula (41) has the same meaning as n3 in general formula (3), and preferred examples are also the same.

Specific examples of monomers corresponding to the repeating unit represented by general formula (41) include those corresponding to the specific examples of monomers corresponding to the repeating unit represented by general formula (41) among the specific examples of monomers corresponding to the repeating unit represented by general formula (1) described above.

The repeating unit represented by general formula (41) contained in resin (P1) may be of one type or of two or more types.

The content ratio of the repeating unit represented by general formula (41) to all repeating units in resin (P1) is not particularly limited, but can be, for example, 40 to 70 mol %.

In formula (51), the organic group of R ₅₁₁ has the same meaning as the organic group of R ₂₁ in formula (2).
The organic group represented by R ₅₁₁ may be the above-mentioned acid-decomposable group, and preferably has a structure in which a phenolic hydroxyl group or a carboxyl group is protected by a group that is eliminated by the action of an acid. It is also preferably a group represented by any one of the general formulae (16) to (17) described below.
The organic group may also be a group that is decomposed by a base as R ₆₁ described below to generate an --OH group or a --COOH group (also referred to as a "base-decomposable group").
Examples of the halogen atom represented by R ₅₁₁ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, with a fluorine atom and a chlorine atom being preferred.

The organic group and halogen atom as R ₅₂ in the general formula (51) include the organic group and halogen atom as R ₂₂ in the general formula (2).
R ₅₂ is preferably an alkyl group or a halogen atom, more preferably an alkyl group, and further preferably a methyl group.

^A5 in formula (51) has the same meaning as ^A3 in formula (3), and preferred examples thereof are also the same.
That is, ^A5 is preferably an aromatic hydrocarbon group, and more preferably a phenylene group.

In the resin (P1), ^A4 in the general formula (41) and ^A5 in the general formula (51) are preferably aromatic ring hydrocarbon groups.

n5 in general formula (51) has the same meaning as n3 in general formula (3), and preferred examples are also the same.

Specific examples of monomers corresponding to the repeating unit represented by general formula (51) include those corresponding to the specific examples of monomers corresponding to the repeating unit represented by general formula (51) among the specific examples of monomers corresponding to the repeating unit represented by general formula (2) described above.

The repeating unit represented by general formula (51) contained in resin (P1) may be of one type or of two or more types.

The content ratio of the repeating unit represented by general formula (51) to all repeating units in resin (P1) is preferably 30 to 60 mol%, more preferably 40 to 55 mol%, and even more preferably 40 to 53 mol%.

Resin (P1) may have a repeating unit other than the repeating unit represented by the general formula (41) and the repeating unit represented by the general formula (51). Examples of the other repeating units include the repeating units having an acid-decomposable group described in the above resin (A) and other repeating units.

The above-mentioned resin (A) can be obtained by having an acid-decomposable group in any of the repeating units of the resin (P1), i.e., by using a monomer having an acid-decomposable group as the raw material monomer of the resin (P1).

<Resin (P2)>
In another preferred embodiment of the resin production method of the present invention, the resin (X) is produced via a resin (P2) that contains at least two kinds of repeating units represented by the following general formula (6), or that contains at least one kind of repeating unit represented by the above general formula (6) and at least one kind of repeating unit represented by the following general formula (7) different from the repeating unit represented by the above general formula (6). Hereinafter, this resin is also referred to as resin (P2).

The production process of resin (P2) is the same as "step (1)" which is the production process of resin (X1) described above.
If resin (P2) is not subjected to any other step (other than step (1)) described below, resin (P2) is resin (X).

In general formula (6), R ₆₁ represents a group that is decomposed by a base to produce an -OH group or a -COOH group (also referred to as a "base-decomposable group"). R ₆₂ represents a hydrogen atom, an organic group, or a halogen atom. A ⁶ represents an aromatic hydrocarbon group, or an aromatic heterocyclic group. n6 represents an integer of 1 to 5. When n6 is an integer of 2 to 5, multiple R ₆₁ may be the same or different.
In general formula (7), R ₇₁ represents an organic group or a halogen atom. R ₇₂ represents a hydrogen atom, an organic group, or a halogen atom. A ⁷ represents an aromatic hydrocarbon group, or an aromatic heterocyclic group. n7 represents an integer of 0 to 5. When n7 is an integer of 2 to 5, multiple R ₇₁ may be the same or different and may be bonded to form a ring.

Monomers with base-decomposable groups cannot be polymerized in living anionic polymerization because they decompose. In addition, living cationic polymerization mainly uses metal compounds as Lewis acid catalysts, which limits the applications due to concerns about metal contamination. Furthermore, because the reaction system is acidic, it is difficult to use monomers with acid-decomposable groups as raw material monomers.

The inventors conducted research to solve the above problems and found that it is possible to polymerize a monomer having a base-decomposable group by performing radical polymerization (NMP) via a nitroxide radical. It was also found that it is possible to polymerize a monomer having a base-decomposable group and a monomer having an acid-decomposable group.

In the general formula (6), R ₆₁ represents a group that is decomposed by a base to generate an —OH group or a —COOH group. Specifically, R ₆₁ is preferably a group represented by any one of the following general formulae (8) to (15).

The organic group represented by _R81 , _R91 , _R101 , _R111 , _R121 , _R131 , _R141 , and _R151 includes an alkyl group, a cycloalkyl group, and an aryl group.
The alkyl group is preferably an alkyl group having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group, an isobutyl group, or a t-butyl group.
The cycloalkyl group is preferably a monocyclic cycloalkyl group such as a cyclopentyl group or a cyclohexyl group, or a polycyclic cycloalkyl group such as a norbornyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, or an adamantyl group.
The aryl group is preferably an aryl group having 6 to 10 carbon atoms, such as a phenyl group or a naphthyl group.

The organic groups represented by _R81 , _R91 , _R101 , _R111 , _R121 , _R131 , _R141 and _R151 may further have a substituent, and the substituent is preferably a halogen atom such as a fluorine atom.

R ₈₁ , R ₉₁ , R ₁₀₁ , R ₁₁₁ , R ₁₂₁ , R ₁₃₁ , R ₁₄₁ and R ₁₅₁ are preferably an alkyl group having 1 to 3 carbon atoms, a trifluoromethyl group or a phenyl group.

R ₆₁ is preferably a group represented by any one of general formulas (8) to (11).

R ₆₂ in formula (6) has the same meaning as R ₃₂ in formula (3), and preferred examples are also the same.
^A6 in formula (6) has the same meaning as ^A3 in formula (3), and preferred examples thereof are also the same.

n6 in general formula (6) has the same meaning as n3 in general formula (3), and preferred examples are also the same.

In addition, R ₈₁ in the above general formula (8) does not bond with A ⁶ to form a ring, and R ₁₂₁ in the above general formula (12) does not bond with A ⁶ to form a ring.

Specific examples of monomers corresponding to the repeating unit represented by general formula (6) are shown below, but the present invention is not limited to these.

The repeating unit represented by general formula (6) contained in resin (P2) may be of one type or of two or more types.

The content ratio of the repeating unit represented by general formula (6) to all repeating units in resin (P2) is not particularly limited, but can be, for example, 50 to 100 mol %.

In formula (7), R ₇₁ has the same meaning as R ₁₁ in formula (3).
R ₇₁ is preferably a group that generates an --OH group or a --COOH group upon acid decomposition, and is more preferably a group represented by any one of the following general formulas (16) to (17).

In formula (16), R ₁₆₁ to R ₁₆₃ each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, a heteroaryl group, an alkenyl group, or an alkynyl group. R ₁₆₁ to R ₁₆₃ may be linked to each other to form a ring.
In formula (17), R ₁₇₁ and R ₁₇₂ each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, a heteroaryl group, an alkenyl group, or an alkynyl group. R ₁₇₃ represents an alkyl group, a cycloalkyl group, an aryl group, a heteroaryl group, an alkenyl group, or an alkynyl group. R ₁₇₁ to R ₁₇₃ may be linked together to form a ring.
* indicates the bonding position with ^A7 .

The alkyl group represented by R ₁₆₁ to R ₁₆₃ may be linear or branched, and may include alkyl groups having 1 to 8 carbon atoms. Preferred are alkyl groups having 1 to 4 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a t-butyl group.

The cycloalkyl group represented by R ₁₆₁ to R ₁₆₃ may be a monocyclic or polycyclic cycloalkyl group having 3 to 10 carbon atoms, preferably a monocyclic cycloalkyl group having 4 to 6 carbon atoms, and more preferably a cyclopentyl group or cyclohexyl group.

Examples of the aryl group represented by R ₁₆₁ to R ₁₆₃ include aryl groups having 6 to 15 carbon atoms, such as a phenyl group and a naphthyl group.

Examples of the heteroaryl group represented by R ₁₆₁ to R ₁₆₃ include heteroaryl groups having 2 to 15 carbon atoms, such as a furyl group, a thienyl group, a thiazolyl group, a pyrrolyl group, an oxazolyl group, a pyridyl group, a benzofuranyl group, a benzothienyl group, a quinolinyl group, and a carbazolyl group.

The alkenyl group represented by R ₁₆₁ to R ₁₆₃ includes an alkenyl group having 2 to 6 carbon atoms, and is preferably an alkenyl group having 2 to 4 carbon atoms, such as a vinyl group, a 1-methylvinyl group, a 1-propenyl group, an allyl group, or a 2-methyl-1-propenyl group.

The alkynyl group represented by R ₁₆₁ to R ₁₆₃ includes an alkynyl group having 2 to 6 carbon atoms.

When R ₁₆₁ to R ₁₆₃ are linked to each other to form a ring, it is preferable that two of R ₁₆₁ to R ₁₆₃ are linked to form a cycloalkyl group or a cycloalkenyl group.

The cycloalkyl group formed by combining two of R ₁₆₁ to R ₁₆₃ includes a monocyclic or polycyclic cycloalkyl group having 3 to 10 carbon atoms, and is preferably a monocyclic cycloalkyl group such as a cyclopentyl group or a cyclohexyl group, and is further preferably a polycyclic cycloalkyl group such as a norbornyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, or an adamantyl group. Of these, a monocyclic cycloalkyl group having 5 to 6 carbon atoms is preferred.

The cycloalkenyl group formed by combining two of R ₁₆₁ to R ₁₆₃ includes monocyclic or polycyclic cycloalkenyl groups having 3 to 10 carbon atoms, and among these, monocyclic cycloalkenyl groups having 5 to 6 carbon atoms are preferred.

The substituents represented by R ₁₆₁ to R ₁₆₃ may be further substituted with an organic group. The organic group preferably contains 0 to 1 heteroatom.
When each group of the above-mentioned substituents represented by R ₁₆₁ to R ₁₆₃ is substituted with an organic group, examples of the organic group include an alkyl group (having 1 to 4 carbon atoms), an alkoxy group (having 1 to 4 carbon atoms), etc. One of the methylene groups in the above-mentioned substituents represented by R ₁₀₄ to R ₁₀₆ may be replaced with a group having a hetero atom such as a carbonyl group.

In the cycloalkyl group or cycloalkenyl group formed by combining two of R ₁₆₁ to R ₁₆₃ , for example, one of the methylene groups constituting the ring may be replaced by a heteroatom such as an oxygen atom or a sulfur atom, or a group having a heteroatom such as a carbonyl group.

It is more preferable that the total number of heteroatoms contained in R ₁₆₁ to R ₁₆₃ is 0 to 1.

Each of R ₁₆₁ to R ₁₆₃ preferably contains 1 to 7 carbon atoms.

In formula (17), R ₁₇₁ and R ₁₇₂ each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, a heteroaryl group, an alkenyl group, or an alkynyl group. R ₁₇₃ represents an alkyl group, a cycloalkyl group, an aryl group, a heteroaryl group, an alkenyl group, or an alkynyl group. R ₁₇₁ to R ₁₇₃ may be linked together to form a ring.

The alkyl group, cycloalkyl group, aryl group, heteroaryl group, alkenyl group, and alkynyl group represented by R ₁₇₁ to R ₁₇₃ include the alkyl group, cycloalkyl group, aryl group, heteroaryl group, alkenyl group, and alkynyl group represented by R ₁₆₁ to R ₁₆₃ in the above general formula (16).

The substituents represented by R ₁₇₁ to R ₁₇₃ may be further substituted with an organic group. The organic group preferably contains 0 to 1 heteroatom.
When each group of the above-mentioned substituents represented by R ₁₇₁ to R ₁₇₃ is substituted with an organic group, examples of the organic group include an alkyl group (having 1 to 4 carbon atoms), an alkoxy group (having 1 to 4 carbon atoms), etc. One of the methylene groups in the above-mentioned substituents represented by R ₁₇₁ to R ₁₇₃ may be replaced with a group having a hetero atom such as a carbonyl group.

R ₁₇₃ may be bonded to A ⁷ in general formula (7) to form a ring. The ring formed is preferably a 5-membered or 6-membered ring, and in this case, R ₁₇₃ preferably represents a single bond or -C(=O)-.

R ₇₂ in formula (7) has the same meaning as R ₃₂ in formula (3), and preferred examples are also the same.
^A7 in formula (7) has the same meaning as ^A3 in formula (3), and preferred examples thereof are also the same.

n7 in general formula (7) has the same meaning as n3 in general formula (3), and the preferred examples are also the same.

The repeating unit represented by the above general formula (7) is preferably a repeating unit represented by the following general formula (18). The repeating unit represented by the following general formula (18) is a repeating unit having a group that generates an -OH group upon acid decomposition.

R ₁₈₄ in formula (18) has the same meaning as R ₃₂ in formula (3), and preferred examples are also the same.

A ¹⁸ in formula (18) has the same meaning as A ³ in formula (3), and preferred examples are also the same.

R ₁₈₁ to R ₁₈₃ in formula (18) have the same meaning as R ₁₆₁ to R ₁₆₃ in formula (16), and preferred examples thereof are also the same.

Examples of monomers corresponding to the repeating unit represented by general formula (7) include those corresponding to the repeating unit represented by general formula (7) among the specific examples of monomers corresponding to the repeating unit represented by general formula (1) described above and specific examples of monomers corresponding to the repeating unit represented by general formula (2).

When resin (P2) has a repeating unit represented by general formula (7), the repeating unit represented by general formula (7) may be of one type or of two or more types.

When resin (P2) has a repeating unit represented by general formula (7), the content ratio of the repeating unit represented by general formula (7) to all repeating units in resin (P2) is not particularly limited, but can be, for example, 10 to 40 mol %.

Resin (P2) preferably contains at least two kinds of repeating units in which R ₆₁ in the above general formula (6) is a group represented by any one of the above general formulas (8) to (15).

It is also preferred that the resin (P2) contains at least two types of repeating units in which ^A6 in the above general formula (6) is an aromatic ring hydrocarbon group, or contains at least one type each of a repeating unit in which ^A6 in the above general formula (6) is an aromatic ring hydrocarbon group and a repeating unit in which ^A7 in the above general formula (7) is an aromatic ring hydrocarbon group.

The resin (X) may have at least one selected from a repeating unit derived from an acrylic monomer and a methacrylic repeating unit.
The content of at least one selected from the repeating units derived from acrylic monomers and the methacrylic repeating units relative to all repeating units in the resin (X) is not particularly limited, but is preferably 10 mol % or less.

The weight average molecular weight (Mw) of the resin (X), as calculated in terms of polystyrene by the GPC method, is preferably 1000 or more, more preferably 2000 or more, even more preferably 4000 or more, and particularly preferably 5000 or more. Also, it is preferably 30000 or less, more preferably 15000 or less.
The dispersity (molecular weight distribution, Pd, Mw/Mn) of the resin (X) is preferably from 1 to 5, more preferably from 1 to 3, even more preferably from 1.0 to 3.0, and particularly preferably from 1.1 to 2.0.

The method for producing a resin of the present invention may include other steps in addition to the step (1) described above. For example, when the resin (P1) or the resin (P2) contains a repeating unit having a base-decomposable group or an acid-decomposable group, the method may include a step of decomposing these groups (also referred to as step (2)).
The resin (P1) and the resin (P2) are collectively referred to as the resin (P).

[Step (2) (decomposition step)]
The step (2) is a step of decomposing a base-decomposable group or an acid-decomposable group that may be contained in the resin (P) to produce a resin (P').

<Decomposition reaction of base-decomposable group>
For example, when resin (P) is the above-mentioned resin (P2), in step (2), R ₆₁ in the repeating unit represented by the above general formula (6) in resin (P2) can be decomposed with a base to give a repeating unit represented by the following general formula (6-1) or a repeating unit represented by general formula (6-2).

R ₆₂ , A ⁶ and n6 in the general formula (6-1) and the general formula (6-2) have the same meanings as R ₆₂ , A ⁶ and n6 in the general formula (6), and preferred examples are also the same.

(base)
As the base, for example, triethylamine, tetra-n-butylammonium fluoride, pyridine, diazabicycloundecene, etc. can be used.
The amount of the base is preferably 1 to 5 molar equivalents, more preferably 1.2 to 3 molar equivalents, based on the base-decomposable groups in the resin.

(solvent)
The base decomposition reaction is typically carried out in a liquid phase, i.e., the reaction system described above typically further contains a solvent.
The solvent is not particularly limited as long as it dissolves each component, but examples thereof include the solvents listed in step (1) and ether solvents.

These solvents may be used alone or in combination of two or more.

The reaction temperature is usually from 10°C to 100°C, preferably from 20°C to 80°C, and more preferably from 40°C to 80°C.
The reaction time is usually 3 to 48 hours, preferably 3 to 24 hours, and more preferably 6 to 12 hours.

Conventionally, when synthesizing a resin having a repeating unit having an acid group and a repeating unit having an acid-decomposable group, it was necessary to once deprotect all of the repeating units having the acid-decomposable group to convert them to acid groups, and then to reprotect only some of the acid groups, making it difficult to control the reactivity.
On the other hand, in the method for producing a resin of the present invention, for example, in the above step (1), a resin having a repeating unit represented by general formula (6) and a repeating unit represented by general formula (7), in which R ₇₁ in the repeating unit represented by general formula (7) is a group that generates an —OH group or a —COOH group upon acid decomposition, is produced, and in step (2), a base-decomposable group in the repeating unit represented by general formula (6) is selectively deprotected to convert it to an acid group, thereby easily synthesizing a resin having a repeating unit having an acid group and a repeating unit having an acid-decomposable group.

<Decomposition reaction of acid-decomposable group>
For example, when resin (P) is the above-mentioned resin (P1), and R ₄₁₁ in the repeating unit represented by general formula (41) is a group that generates an —OH group or a —COOH group upon acid decomposition, in step (2), R ₄₁₁ can be acid-decomposed to give a repeating unit represented by general formula (2-1) or a repeating unit represented by general formula (2-2) below.

R ₄₂ , A ⁴ and n4 in the general formulae (2-1) and (2-2) have the same meanings as R ₄₂ , A ⁴ and n4 in the general formula (41), and preferred examples are also the same.

(acid)
As the acid, for example, hydrochloric acid, p-toluenesulfonic acid, hydrobromic acid, etc. can be used.
The amount of the acid is preferably 1 to 5 molar equivalents, more preferably 1.2 to 3 molar equivalents, based on the acid-decomposable groups in the resin.

(solvent)
The acidolysis reaction is typically carried out in a liquid phase, i.e., the reaction system typically further comprises a solvent.
The solvent is not particularly limited as long as it dissolves each component, but examples thereof include the solvents listed in step (1) and ether solvents.

These solvents may be used alone or in combination of two or more.

[Process (3) (protection process)]
The method for producing a resin of the present invention further includes a step (2) of protecting a phenolic hydroxyl group and a carboxyl group in the repeating unit of the resin (P′) obtained in the step (2) to produce a resin (P″). The method may include a step (3).

For example, when the resin (P') has a repeating unit represented by the above general formula (2-1), in step (3), the phenolic hydroxyl group can be reprotected by reacting it with a halogenated compound represented by X-Rc to give a repeating unit represented by the following general formula (2-1c).

In the compound represented by X-Rc, X represents a halogen atom, preferably a chlorine atom. Rc represents a group that is eliminated by the action of an acid. Specific examples include the above-mentioned leaving groups.

R ₄₂ , A ⁴ and n4 in formula (2-1c) have the same meanings as R ₄₂ , A ⁴ and n4 in formula (41), and preferred examples are also the same.

In this way, by step (3), a repeating unit having the desired acid-decomposable group can be introduced into the resin.

The amount of the compound represented by X-Rc added is not particularly limited and may be adjusted appropriately depending on the desired resin structure.

(base)
The above protection reaction can be carried out in the presence of a base, such as triethylamine, pyridine, potassium carbonate, etc.
The amount of the base used may be, for example, 1 to 5 moles per mole of the compound represented by X--Rc.

(solvent)
The reaction is typically carried out in a liquid phase, i.e., the reaction system typically further comprises a solvent.
The solvent is not particularly limited as long as it dissolves each component, but examples thereof include the solvents listed in step (1) and ether solvents.

These solvents may be used alone or in combination of two or more.

The reaction temperature is usually from -10°C to 30°C, preferably from -10°C to 20°C, and more preferably from 0°C to 20°C.
The reaction time is usually from 1 to 6 hours, preferably from 1 to 4 hours, and more preferably from 1 to 2 hours.

The present invention will be described in more detail below based on examples. The materials, amounts used, ratios, processing contents, and processing procedures shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be interpreted as being limited by the examples shown below.

[Resin synthesis example]
Synthesis Example 1: Synthesis of Resin P-1

A monomer solution was prepared by mixing the monomers (A-1) and (AA-1) in a molar ratio of (A-1):(AA-1) = 50/50, and adding acetic anhydride to the solution so that the monomer concentration became 75% by mass. This solution was divided into two portions in a mass ratio of 30:70, which were designated as Monomer Solution A and Monomer Solution B, respectively.
To the monomer solution A, dimethyl 2,2'-azobis(2-methylpropionate) (I-1) was added as an initiator in an amount of 0.030 molar equivalents relative to the total amount of monomers, and 2,2,6,6-tetramethylpiperidine 1-oxyl (N-1) was added as a nitroxide radical source in an amount of 0.042 molar equivalents relative to the total amount of monomers. In a nitrogen atmosphere, the monomer solution A was dropped into a reaction vessel at 80°C over 1 hour, and then heated at 80°C for another 1 hour. The monomer solution B, which had been heated to 130°C, was dropped into the liquid over 3 hours, and then reacted at 130°C for 1 hour. The obtained resin solution was dropped into a mixed solvent of ethyl acetate:n-heptane = 1:9 (mass ratio), the resin was precipitated, filtered, collected, and then vacuum dried to obtain a resin (P-1) with a yield of 75%. The introduction ratio of (A-1):(AA-1) was 58/42, the Mw was 5,400, and the Mw/Mn was 1.19.

P-2 to P-37, P-1AA, and P-1BB were synthesized in the same manner as above, except that the monomers and their ratios, solvent, monomer concentration, initiator, nitroxide radical source and its molar equivalent, and monomer solution B dripping time and dripping temperature were changed.

<Synthesis Example 2: Synthesis of Resin P'-1> (Method of dripping monomer liquid B without heating)

A monomer solution was prepared by mixing the monomers (A-1) and (AA-1) in a molar ratio of (A-1):(AA-1) = 50/50, and adding acetic anhydride to the solution so that the monomer concentration became 75% by mass. This solution was divided into two portions in a mass ratio of 30:70, which were designated as Monomer Solution A and Monomer Solution B, respectively.
To the monomer solution A, 0.030 molar equivalents of dimethyl 2,2'-azobis(2-methylpropionate) (I-1) was added as an initiator relative to the total amount of monomers, and 0.042 molar equivalents of 2,2,6,6-tetramethylpiperidine 1-oxyl (N-1) was added as a nitroxide radical source relative to the total amount of monomers. In a nitrogen atmosphere, the monomer solution A was dropped into a reaction vessel at 80°C over 1 hour, and then heated at 80°C for another 1 hour. After the liquid was heated to 130°C (the temperature of the monomer solution A before the drop of the monomer solution B), the monomer solution B at room temperature of 25°C was dropped over 3 hours, and then the reaction was carried out at 130°C for 1 hour. The obtained resin solution was dropped into a mixed solvent of ethyl acetate:n-heptane = 1:9 (mass ratio), the resin was precipitated, filtered, collected, and then vacuum dried to obtain a resin (P-1) with a yield of 75%. The introduction ratio of (A-1):(AA-1) was 58/42, the Mw was 5550, and the Mw/Mn was 1.20.

P'-2, P'-5, P'-7, P'-8, P'-16, P'-34, and P'-36 were synthesized in the same manner as above, except that the monomers used and their ratios, the solvent, the monomer concentration, the initiator, the nitroxide radical source and its molar equivalent, the time and temperature of monomer solution B dripping, and the temperature of monomer solution A before dripping monomer solution B were changed.

Tables 1 and 2 show the synthesis conditions, resin compositions (types of raw material monomers, monomer introduction rates (molar ratios)), resin weight average molecular weights (Mw), and dispersity (Mw/Mn)) for P-1 to P-37, P-1AA, and P-1BB, as well as P'-1, P'-2, P'-5, P'-7, P'-8, P'-16, P'-34, and P'-36.
The weight average molecular weight (Mw) and dispersity (Mw/Mn) of the resin were measured by GPC (carrier: tetrahydrofuran (THF)) (polystyrene equivalent amount). The repeating unit content was measured by ¹³ C-NMR (nuclear magnetic resonance).

In Tables 1 and 2, Ac2O stands for acetic anhydride, PGMEA stands for propylene glycol monomethyl ether acetate, and DAA stands for diacetone alcohol. When two types of reaction solvents are used, the ratios shown in the tables are by mass.

In P-1 to P-37, P-1AA, and P-1BB in Table 1 above, the raw material monomers are as follows.
In addition, in P'-1, P'-2, P'-5, P'-7, P'-8, P'-16, P'-34, and P'-36 in Table 2 above, the raw material monomers are as follows.

The compounds used as initiators in Tables 1 and 2 above are as follows:

The compounds used as nitroxide radical sources in Tables 1 and 2 above are as follows:

10.0 g of cyclohexanone, 15.0 g of methanol, and 10.11 g of triethylamine (99.95 mmol, 2.1 equivalents relative to the total moles of base-decomposable protecting group units (A-1 and AA-1)) were added to 8 g of resin (P-1), and the mixture was heated to reflux at the boiling point and reacted for 24 hours. After cooling, 200 g of ethyl acetate, 80 g of water, and 4.8 g of acetic acid (79.96 mmol, 1.7 equivalents relative to the base-decomposable protecting group units) were added for neutralization. After removing the water layer, the mixture was washed with water (80 g) five times. The resulting resin solution was concentrated and then dropped into a mixed solvent of ethyl acetate:n-heptane = 1:9 (mass ratio) to precipitate the resin, which was then filtered, collected, and vacuum dried to obtain resin Pa-1 with a yield of 91%.

80 g of tetrahydrofuran (THF) and 8.03 g (79.4 mmol) of triethylamine were added to 5.00 g of resin (Pa-1) and cooled to 0°C. 2.40 g (14.6 mmol) of 1-chloro-1-isopropoxy-2,2-dimethylpropane were added dropwise, and the mixture was allowed to react for 1 hour after being heated to room temperature. 200 g of ethyl acetate and 80 g of water were added to the resulting reaction solution and separated. After removing the water layer, the mixture was washed with water (80 g) four more times. The resulting resin solution was concentrated and then dropped into a mixed solvent of ethyl acetate:n-heptane = 1:9 (mass ratio) to precipitate the resin, which was then filtered, collected, and vacuum dried to obtain resin Pb-1 with a yield of 95%.

8 g of resin (P-16) was mixed with 10.0 g of cyclohexanone, 15.0 g of methanol, and 5 ml of 1 mol% HClaq, and then heated to 50°C and reacted for 6 hours. After cooling, 200 g of ethyl acetate and 80 g of water were added and washed with water. After removing the water layer, water washing (80 g) was performed five times. The resulting resin solution was concentrated and then dropped into a mixed solvent of ethyl acetate:n-heptane = 1:9 (mass ratio) to precipitate the resin, which was then filtered, collected, and vacuum dried to obtain resin Pa-16 with a yield of 93%.

80 g of THF and 8.03 g (79.4 mmol) of triethylamine were added to 5.00 g of resin (Pa-16) and cooled to 0°C. 2.76 g (13.5 mmol) of (1-chloro-1-methoxypropan-2-yl)cyclohexane were added dropwise, and the mixture was allowed to react for 1 hour after being heated to room temperature. 200 g of ethyl acetate and 80 g of water were added to the resulting reaction solution and separated. After removing the water layer, the mixture was washed with water (80 g) four more times. The resulting resin solution was concentrated and then dropped into a mixed solvent of ethyl acetate:n-heptane = 1:9 (mass ratio) to precipitate the resin, which was then filtered, collected, and vacuum dried to obtain resin Pb-16 with a yield of 94%.

80 ml of 1 mol% tetra-n-butylammonium fluoride THF solution was added to 8 g of resin (P-7), heated to 60°C, and reacted for 6 hours. After cooling, 200 g of ethyl acetate and 80 g of water were added and washed with water. After removing the water layer, water washing (80 g) was performed five times. The resulting resin solution was concentrated and then dropped into a mixed solvent of ethyl acetate:n-heptane = 1:9 (mass ratio) to precipitate the resin, which was then filtered, collected, and vacuum dried to obtain resin Pa-7 with a yield of 93%.

　The following Pb-1AA, Pb-1BB, Pa-2, Pa-3, Pa-8, Pa-11, Pa-12, Pa-14, Pa-17, Pa-18, Pa-20, Pa-21, Pa-25, Pa-26, Pa-29, Pa-35, Pa-36, Pa-37, Pb-11, Pb-14, Pa'-1, Pa'-2, Pa'-7, Pa'-8, Pa'-16, Pb'-16, Pa'-36 were synthesized in the same manner as Pa-1, Pb-1, Pa-16, and Pa-7 above.

(A-1) and (AA-1) were used as monomers, and each monomer was mixed to a molar ratio of (A-1):(AA-1) = 50/50, and acetic anhydride was added to the solution so that the monomer concentration was 75 mass% to prepare a monomer solution. 8 mol% of dimethyl 2,2'-azobis(2-methylpropionate) was added as an initiator. 0.1 mass times of acetic anhydride was heated to 130°C under a nitrogen atmosphere, and the monomer solution to which the initiator was added was dropped over 2 hours, and then reacted at 130°C for another 2 hours. The resulting resin solution was dropped into a mixed solvent of ethyl acetate:n-heptane = 1:9, and the resin was precipitated. It was filtered, recovered, and then vacuum dried to obtain resin (P-1A) with a yield of 35%. The introduction ratio of (A-1):(AA-1) = 72/28, Mw was 3900, and Mw/Mn was 1.67.

Compared to resin P-1 obtained by the manufacturing method of the present invention, resin P-1A synthesized without using nitroxide radicals had a lower introduction ratio of monomer (AA-1) and a smaller molecular weight, even though the charge ratio of monomers (A-1) and (AA-1) was the same as in Synthesis Example 1.

<Reference Synthesis Example 2: Synthesis of Resin P-1B (without using nitroxide)>
(A-1) and (AA-1) were used as monomers, and each monomer was mixed to a molar ratio of (A-1):(AA-1)=30/70, and acetic anhydride was added to the solution so that the monomer concentration was 75% by mass to prepare a monomer solution. 8 mol% of dimethyl 2,2'-azobis(2-methylpropionate) was added as an initiator. 0.1 mass times of acetic anhydride was heated to 130°C under a nitrogen atmosphere, and the monomer solution to which the initiator was added was dropped over 2 hours, and then reacted at 130°C for another 2 hours. The resulting resin solution was dropped into a mixed solvent of ethyl acetate:n-heptane=1:9, and the resin was precipitated, filtered, collected, and then vacuum dried to obtain a resin (P-1B) with a yield of 25%. At an introduction ratio of (A-1):(AA-1)=55/45, Mw was 2300, and Mw/Mn was 1.64.

Compared to resin P-1 obtained by the manufacturing method of the present invention, resin P-1B was synthesized without using nitroxide radicals. By increasing the monomer (AA-1) feed ratio significantly more than in synthesis example 1, the monomer (AA-1) introduction ratio was the same, but the yield was lower and the molecular weight was smaller.

(B-1) and (BB-1) were used as monomers, and each monomer was mixed to a molar ratio of (B-1):(BB-1) = 50/50, and acetic anhydride was added to the solution so that the monomer concentration became 75 mass% to prepare a monomer solution. 8 mol% of dimethyl 2,2'-azobis(2-methylpropionate) was added as an initiator. 0.1 mass times of acetic anhydride was heated to 130°C under a nitrogen atmosphere, and the monomer solution to which the initiator was added was dropped over 2 hours, and then reacted at 130°C for another 2 hours. The obtained resin solution was dropped into a mixed solvent of ethyl acetate:n-heptane = 1:9, and the resin was precipitated. After filtering and collecting, it was vacuum dried to obtain resin (P-16A) with a yield of 38%. The introduction ratio of (B-1):(BB-1) = 69/31, Mw was 3800, and Mw/Mn was 1.60.

Compared to resin P-16 obtained by the manufacturing method of the present invention, resin P-16A synthesized without using nitroxide radicals had a lower introduction ratio of monomer (BB-1) and a smaller molecular weight, despite the same feed ratio of monomers (B-1) and (BB-1).

The synthesis method for the comparative resin used in the performance evaluation of the resist composition is shown below.

(C-1) and (B-1) were used as monomers, and the monomers were mixed in a molar ratio of (C-1):(B-1) = 66/34. Cyclohexanone was added so that the monomer concentration of the solution was 30% by mass, and 8 mol% of dimethyl 2,2'-azobis(2-methylpropionate) was added as an initiator. 0.1 mass of cyclohexanone was heated to 85°C under a nitrogen atmosphere, and the monomer solution was added dropwise over 2 hours, and then the reaction was continued for another 2 hours at 85°C. The resulting resin solution was dropped into a mixed solvent of ethyl acetate:n-heptane = 1:9, and the resin was precipitated. It was filtered, collected, and then vacuum dried to obtain resin (PX-1) with a yield of 69%.

The following resins PX-2, PX-3, PX-7, PX-11, PX-14, PX-16, PX-17, PX-20, PX-21, PX-25, PX-26, and PX-29 were also synthesized in the same manner as resin PX-1.

[Resist Composition]
The various components used in the resist compositions of the examples and comparative examples are shown below.

<Resin (A)>
As the resin (A), the resin shown above was used.

<Photoacid Generator (B)>
As the photoacid generator (B), BX-1 to BX-2 were used.

<Acid Diffusion Controller (C)>
As the acid diffusion controller (C), C-1 to C-14 were used.

<Hydrophobic resin>
D-1 was used as the hydrophobic resin. The content ratio of the repeating unit (content relative to the total repeating units in the resin) is a molar ratio.

<Surfactant>
As the surfactants, the following W-1 to W-4 were used.
W-1: Megafac R08 (manufactured by Dainippon Ink and Chemicals, Inc.; fluorine and silicone type)
W-2: Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.; silicone-based)
W-3: Troysol S-366 (manufactured by Troy Chemical Co., Ltd.; fluorine-based)
W-4: PF6320 (manufactured by OMNOVA; fluorine-based)

<Solvent>
The solvents used are shown below.
S-1: Diacetone alcohol (DAA)
S-2: Propylene glycol monomethyl ether acetate (PGMEA)
S-3: Propylene glycol monomethyl ether (PGME)
S-4: Ethyl lactate (EL)
S-5: Ethyl 3-ethoxypropionate (EEP)
S-6: 2-heptanone (MAK)
S-7: methyl 3-methoxypropionate (MMP)
S-8: 3-methoxybutyl acetate S-9: γ-butyrolactone

<Preparation of Resist Composition>
Each component other than the solvent shown in Table 3 was used in the content (mass %) shown in Table 3 and mixed with the solvent shown in Table 3 to obtain a solution. The content of each component is the mass ratio to the total solid content of the resist composition. The obtained solution was filtered through a polyethylene filter having a pore size of 0.02 μm to obtain resist compositions R-1 to R-25 and RX-1 to RX-7. The solid content concentration of the resist composition was adjusted to the concentration shown in Table 3. The solid content means all components other than the solvent. The obtained resist composition was used in the examples and comparative examples. Table 3 shows the type of solvent used and its mass ratio.

<Coating of resist composition>
The prepared resist composition was applied onto a 6-inch Si (silicon) wafer that had been previously treated with hexamethyldisilazane (HMDS) using a spin coater Mark 8 manufactured by Tokyo Electron, and then dried on a hot plate at 130° C. for 300 seconds to obtain a resist film with a thickness of 100 nm.
It should be noted that the same results can be obtained even if the Si wafer is replaced with a chromium substrate.

(Examples 1a to 25a, Comparative Examples 1a to 7a)
<Pattern formation method (1): EB exposure, alkaline development (positive)>
The wafer coated with the resist film obtained above was subjected to pattern irradiation using an electron beam lithography device (Advantest Corporation; F7000S, acceleration voltage 50 keV). At this time, lithography was performed so that a 1:1 line and space was formed. After electron beam lithography, the wafer was heated on a hot plate at 100° C. for 60 seconds, immersed in a 2.38 mass% tetramethylammonium hydroxide (TMAH) aqueous solution for 60 seconds, rinsed with water for 30 seconds, and dried. Thereafter, the wafer was rotated at a rotation speed of 4000 rpm for 30 seconds, baked at 95° C. for 60 seconds, and dried.

〔evaluation〕
The obtained patterns were evaluated for resolution and LWR performance by the following methods, and the results are shown in the table below.

The irradiation energy required to resolve a 1:1 line and space pattern with a line width of 50 nm was defined as the sensitivity (Eop).

<L/S resolution>
The limiting resolving power (the minimum line width at which a line and a space (line:space=1:1) are resolved separately) at the exposure dose exhibiting the above sensitivity (Eop) was taken as the resolving power (nm).

<Line width roughness (LWR) performance>
The line width roughness was measured at the above Eop by measuring the line width at 50 arbitrary points in the longitudinal direction of 0.5 μm of a line and space pattern (line:space=1:1) with a line width of 50 nm, determining the standard deviation, and calculating 3σ (nm). A smaller value indicates better performance.

The resist compositions used and the results are shown in Table 4 below.

(Examples 1b to 25b, Comparative Examples 1b to 7b)
<Pattern formation method (2): EUV exposure, alkaline development (positive)>
The same steps as in the above pattern formation method (1) were carried out, except that an EUV exposure apparatus (Micro Exposure Tool manufactured by Exitech, NA (numerical aperture) 0.3, quadrupole, outer sigma 0.68, inner sigma 0.36) was used instead of the electron beam lithography apparatus.
The resolution and LWR performance were evaluated in the same manner as described above.
The resist compositions used and the results are shown in Table 5 below.

The results in Tables 4 and 5 show that the composition of the present invention has excellent resolution and LWR performance.

Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the invention.
This application is based on a Japanese patent application (Patent Application No. 2023-016479) filed on February 6, 2023, the contents of which are incorporated herein by reference.

Claims

A resin (A) containing at least one kind of repeating unit represented by the following general formula (1) and at least one kind of repeating unit represented by the following general formula (2):
A compound (B) that generates an acid when exposed to actinic rays or radiation, and a solvent (S).
An actinic ray-sensitive or radiation-sensitive resin composition comprising:

In general formula (1), R 11 represents an organic group, a halogen atom, or a hydroxyl group. R 12 represents a hydrogen atom or an organic group. A 1 represents an aromatic hydrocarbon group or an aromatic heterocyclic group. n1 represents an integer of 0 to 5. When n1 is an integer of 2 to 5, multiple R 11 may be the same or different and may be bonded to form a ring. R 12 and A 1 may be bonded to form a ring.
In general formula (2), R 21 represents an organic group, a halogen atom, or a hydroxyl group. R 22 represents an organic group or a halogen atom. A 2 represents an aromatic hydrocarbon group or an aromatic heterocyclic group. n2 represents an integer of 0 to 5. When n2 is an integer of 2 to 5, multiple R 21 may be the same or different and may be bonded to form a ring.
The actinic ray-sensitive or radiation-sensitive resin composition according to claim 1, wherein the content ratio of the repeating unit represented by the general formula (2) to the total repeating units in the resin (A) is 30 to 60 mol %.
The actinic ray-sensitive or radiation-sensitive resin composition according to claim 1, wherein the weight average molecular weight of the resin (A) is 4,000 or more.
2. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 1, wherein A1 in the general formula (1) and A2 in the general formula (2) are aromatic ring hydrocarbon groups.
A method for producing a resin by polymerizing at least two types of monomers in the presence of a nitroxide radical represented by the following general formula (N) and a radical polymerization initiator to produce a resin (X) containing at least two types of repeating units represented by the following general formula (3):

In formula (N), R 1 each independently represents an organic group. Two R 1 may be bonded to form a ring.

In general formula (3), R 31 represents an organic group, a halogen atom, or a hydroxyl group. R 32 represents a hydrogen atom, an organic group, or a halogen atom. R 33 represents a hydrogen atom or an organic group. A 3 represents an aromatic hydrocarbon group, or an aromatic heterocyclic group. n3 represents an integer of 0 to 5. When n3 is an integer of 2 to 5, multiple R 31 may be the same or different and may be bonded to form a ring. R 33 and A 3 may be bonded to form a ring.
The method for producing a resin according to claim 5 , wherein the resin (X) contains at least one type of repeating unit represented by the following general formula (4) and at least one type of repeating unit represented by the following general formula (5):

In general formula (4), R 41 represents an organic group, a halogen atom, or a hydroxyl group. R 42 represents a hydrogen atom or an organic group. A 4 represents an aromatic hydrocarbon group or an aromatic heterocyclic group. n4 represents an integer of 0 to 5. When n4 is an integer of 2 to 5, multiple R 41 may be the same or different and may be bonded to form a ring. R 42 and A 4 may be bonded to form a ring.
In general formula (5), R 51 represents an organic group, a halogen atom, or a hydroxyl group. R 52 represents an organic group or a halogen atom. A 5 represents an aromatic hydrocarbon group or an aromatic heterocyclic group. n5 represents an integer of 0 to 5. When n5 is an integer of 2 to 5, multiple R 51 may be the same or different and may be bonded to form a ring.
The method for producing a resin according to claim 6, wherein the content ratio of the repeating unit represented by the general formula (5) to the total repeating units in the resin (X) is 30 to 60 mol %.
The method for producing a resin according to claim 6, wherein the weight average molecular weight of the resin (X) is 4000 or more.
The method for producing a resin according to claim 6, wherein A4 in the general formula (4) and A5 in the general formula (5) are aromatic ring hydrocarbon groups.
The method for producing a resin according to claim 6, wherein R 52 in the general formula (5) is an alkyl group.
The method for producing a resin according to claim 5, wherein the resin (X) contains at least two kinds of repeating units represented by the following general formula (6), or is produced via a resin (P2) containing at least one kind each of a repeating unit represented by the general formula (6) and a repeating unit represented by the following general formula (7) different from the repeating unit represented by the general formula (6).

In general formula (6), R 61 represents a group that generates an -OH group or a -COOH group upon decomposition by a base. R 62 represents a hydrogen atom, an organic group, or a halogen atom. A 6 represents an aromatic hydrocarbon group or an aromatic heterocyclic group. n6 represents an integer of 1 to 5. When n6 is an integer of 2 to 5, multiple R 61 may be the same or different.
In general formula (7), R 71 represents an organic group or a halogen atom. R 72 represents a hydrogen atom, an organic group, or a halogen atom. A 7 represents an aromatic hydrocarbon group, or an aromatic heterocyclic group. n7 represents an integer of 0 to 5. When n7 is an integer of 2 to 5, multiple R 71 may be the same or different and may be bonded to form a ring.
The method for producing a resin according to claim 11, wherein R 61 in the general formula (6) is a group represented by any one of the following general formulae (8) to (15):

In formulae (8) to (15), R 91 , R 101 , R 111 , R 121 , R 141 and R 151 each independently represent an organic group, R 81 and R 131 each independently represent a hydrogen atom or an organic group. * represents the bonding position with A 6 .
The method for producing a resin according to claim 12, wherein R 61 in the general formula (6) contains at least two kinds of repeating units which are groups represented by any one of the general formulae (8) to (15).
The method for producing a resin according to claim 11, wherein R 71 in the general formula (7) is a group that generates an --OH group or a --COOH group upon acid decomposition.
The method for producing a resin according to claim 14, wherein R 71 in the general formula (7) is a group represented by any one of the following general formulas (16) to (17):

In formula (16), R 161 to R 163 each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, a heteroaryl group, an alkenyl group, or an alkynyl group. R 161 to R 163 may be linked to each other to form a ring.
In formula (17), R 171 and R 172 each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, a heteroaryl group, an alkenyl group, or an alkynyl group. R 173 represents an alkyl group, a cycloalkyl group, an aryl group, a heteroaryl group, an alkenyl group, or an alkynyl group. R 171 to R 173 may be linked together to form a ring.
* indicates the bonding position with A7 .
The method for producing a resin according to claim 11, wherein the repeating unit represented by the general formula (7) is a repeating unit represented by the following general formula (18):

In general formula (18), R 184 represents a hydrogen atom, an organic group, or a halogen atom. A 18 represents an aromatic hydrocarbon group, or an aromatic heterocyclic group. R 181 to R 183 each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, a heteroaryl group, an alkenyl group, or an alkynyl group. Two of R 181 to R 183 may be bonded to each other to form a ring.
The method for producing a resin according to claim 11, wherein the resin (P2) contains at least two types of repeating units in which A6 in the general formula (6) is an aromatic ring hydrocarbon group, or contains at least one type each of a repeating unit in which A6 in the general formula (6) is an aromatic ring hydrocarbon group and a repeating unit in which A7 in the general formula (7) is an aromatic ring hydrocarbon group.
A resin containing at least one type of repeating unit represented by the following general formula (1) and at least one type of repeating unit represented by the following general formula (2):

In general formula (1), R 11 represents an organic group, a halogen atom, or a hydroxyl group. R 12 represents a hydrogen atom or an organic group. A 1 represents an aromatic hydrocarbon group or an aromatic heterocyclic group. n1 represents an integer of 0 to 5. When n1 is an integer of 2 to 5, multiple R 11 may be the same or different and may be bonded to form a ring. R 12 and A 1 may be bonded to form a ring.
In general formula (2), R 21 represents an organic group, a halogen atom, or a hydroxyl group. R 22 represents an organic group or a halogen atom. A 2 represents an aromatic hydrocarbon group or an aromatic heterocyclic group. n2 represents an integer of 0 to 5. When n2 is an integer of 2 to 5, multiple R 21 may be the same or different and may be bonded to form a ring.
The resin according to claim 18, wherein the content ratio of the repeating unit represented by the general formula (2) to the total repeating units in the resin is 30 to 60 mol %.
The resin according to claim 18, having a weight average molecular weight of 4000 or more.
The resin according to any one of claims 18 to 20, wherein A 1 in the general formula (1) and A 2 in the general formula (2) are aromatic ring hydrocarbon groups.
An actinic ray-sensitive or radiation-sensitive film formed using the actinic ray-sensitive or radiation-sensitive resin composition according to any one of claims 1 to 4.
A pattern forming method comprising the steps of forming an actinic ray-sensitive or radiation-sensitive film on a substrate using the actinic ray-sensitive or radiation-sensitive resin composition according to any one of claims 1 to 4, exposing the actinic ray-sensitive or radiation-sensitive film, and developing the exposed actinic ray-sensitive or radiation-sensitive film using a developer.
A method for manufacturing an electronic device comprising the pattern formation method according to claim 23.