JPWO2012002470A1 - Radiation sensitive resin composition, polymer and compound - Google Patents

Abstract

The present invention is [A] a radiation-sensitive resin composition containing a polymer having a structural unit (I) represented by the following formula (1) and [B] a solvent. In the following formula (1), RC is a group that forms a divalent aliphatic cyclic hydrocarbon group together with Ra. Ra is a carbon atom. The structural unit (I) is preferably a structural unit (I-1) represented by the following formula (1-1). The structural unit (I) is also preferably a structural unit (I-2) represented by the following formula (1-2).

Description

  The present invention relates to a radiation-sensitive resin composition, a polymer suitable as a component of the radiation-sensitive resin composition, and a compound suitable as a monomer of the polymer.

  In the field of microfabrication represented by the manufacture of integrated circuit elements, conventionally, a resist film is formed on a substrate with a resin composition containing a polymer having an acid dissociable group, and the resist film is formed on the resist film via a mask pattern. A fine resist pattern is formed by irradiating a short-wavelength radiation (excimer laser light or the like) for exposure and removing an exposed portion with an alkali developer. In that case, the radiation sensitive resin composition which contained the radiation sensitive acid generator which generate | occur | produces an acid by radiation irradiation in the said resin composition, and improved the sensitivity by the effect | action of the acid is utilized.

  In such a radiation-sensitive resin composition, post-exposure baking (PEB) is performed in order to promote the dissociation reaction of the acid-dissociable group and ensure sufficient solubility in the alkaline developer in the exposed portion. The PEB temperature is usually about 90 to 180 ° C. However, at such a PEB temperature, the dissociation of the acid-dissociable group is sufficient, but the diffusion of the acid to the unexposed part becomes remarkable, which affects the pattern forming property of the radiation-sensitive resin composition. In particular, at present, when the miniaturization of resist patterns has progressed to a level of 90 nm or less, the pattern shape is good and the LWR (line width roughness) indicating the variation in line width is small. It is difficult to obtain a resist pattern. As a countermeasure, a method of adding an acid diffusion control agent to the radiation-sensitive resin composition is employed, but this is not preferable because it causes an increase in cost.

  Therefore, it is conceivable to reduce the acid diffusion rate by lowering the PEB temperature to eliminate the above disadvantages. In recent years, there has been a strong demand for lowering the PEB temperature and reducing the amount of energy used in the manufacturing process from the viewpoint of reducing environmental burdens and manufacturing costs.

  However, when the PEB temperature is lowered, the rate of the dissociation reaction of the acid dissociable group is also decreased, and the resist film in the exposed portion is not sufficiently dissolved, so that the pattern forming property of the radiation sensitive resin composition is deteriorated. Therefore, it has been studied to lower the PEB temperature by making the acid dissociable group easier to dissociate. As such a radiation-sensitive resin composition, a positive photosensitive resin composition containing a resin having an acid-dissociable group containing a specific acetal structure (see JP 2008-304902 A), a tertiary ester structure A positive resist composition (see JP 2009-276607 A) that contains a resin having a structural unit containing bismuth and a structural unit containing a hydroxyalkyl group has been proposed. However, in these techniques, the degree of dissociation improvement of the acid dissociable group is small, and the possible decrease in the PEB temperature is small, so that the pattern forming property and the LWR performance of the radiation sensitive resin composition are sufficiently obtained. It cannot be improved. In addition, if the PEB temperature is lowered from the conventional temperature, the resin in the exposed area remains undissolved during alkali development, so that a resist residue after development called scum occurs and bridge defects occur in the formed resist pattern. Or the WWR may deteriorate due to this bridging defect.

JP 2008-304902 A JP 2009-276607 A

  The present invention has been made based on the circumstances as described above, and its purpose is to achieve a radiation sensitivity that is excellent in pattern formation, LWR performance, scum suppression, and bridge defect suppression while reducing the PEB temperature. The object is to provide a resin composition.

（式（１）中、Ｒは、水素原子、フッ素原子、メチル基又はトリフルオロメチル基である。Ｒ^Ｃは、Ｒ^ａと共に２価の脂肪族環状炭化水素基を形成する基である。この脂肪族環状炭化水素基の有する水素原子の一部又は全部は置換されていてもよい。Ｒ^ａは、炭素原子である。Ｒ^１〜Ｒ^３は、それぞれ独立して、水素原子、炭素数１〜１０の１価の鎖状飽和炭化水素基又は炭素数３〜２０の１価の脂肪族環状飽和炭化水素基である。この鎖状飽和炭化水素基及び脂肪族環状飽和炭化水素基の有する水素原子の一部又は全部は置換されていてもよい。但し、Ｒ^１〜Ｒ^３のいずれかが互いに結合して環状構造を形成していてもよい。）The invention made to solve the above problems is
[A] A polymer having a structural unit (I) represented by the following formula (1) (hereinafter also referred to as “[A] polymer”), and [B] a radiation-sensitive resin composition containing a solvent. It is.

(In Formula (1), R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R ^C is a group that forms a divalent aliphatic cyclic hydrocarbon group together with R ^a . Some or all of the hydrogen atoms of the aliphatic cyclic hydrocarbon group may be substituted, R ^a is a carbon atom, and R ^{1 to} R ³ are each independently a hydrogen atom or a carbon number of 1 To a monovalent chain saturated hydrocarbon group having from 10 to 10 or a monovalent aliphatic cyclic saturated hydrocarbon group having from 3 to 20 carbon atoms, hydrogen contained in the chain saturated hydrocarbon group and the aliphatic cyclic saturated hydrocarbon group. (Part or all of the atoms may be substituted, provided that any of R ^{1 to} R ³ may be bonded to each other to form a cyclic structure.)

The radiation sensitive resin composition contains an [A] polymer having a structural unit (I) represented by the above formula (1) and a [B] solvent. The structural unit (I) includes, as an acid dissociable group, a carbon atom (R ^a ) bonded to an ester group of a divalent aliphatic cyclic hydrocarbon group formed from an R ^C group and a carbon atom (R ^a ). And a group including a structure in which a carbon-carbon double bond is adjacent (hereinafter also referred to as “double bond adjacent cyclic hydrocarbon group”). This double bond adjacent cyclic hydrocarbon group has a positive charge on R ^a that is induced in the dissociation reaction of the acid dissociable group because R ^a is an allylic position of the carbon-carbon double bond. It is considered that the dissociation property of the acid dissociable group is very high. Therefore, according to the said radiation sensitive resin composition, PEB temperature can be lowered | hung from the conventional temperature, As a result, the spreading | diffusion of an acid is optimized and a favorable pattern shape and a resist pattern with small LWR are formed. Is possible. In addition, since the dissociation property of the acid dissociable group is very high, the polymer in the exposed area can be sufficiently dissolved in the alkaline developer even when the PEB temperature is lowered, so that scum is generated during development. It is possible to form a resist pattern that is suppressed and generation of bridge defects is suppressed.

（式（１−１）中、Ｒ及びＲ^１〜Ｒ^３は、上記式（１）と同義である。ｎ_Ｃは、１〜４の整数である。Ｒ^Ｓは、−Ｒ^Ｐ１、−Ｒ^Ｐ２−Ｏ−Ｒ^Ｐ１、−Ｒ^Ｐ２−ＣＯ−Ｒ^Ｐ１、−Ｒ^Ｐ２−ＣＯ−ＯＲ^Ｐ１、−Ｒ^Ｐ２−Ｏ−ＣＯ−Ｒ^Ｐ１、−Ｒ^Ｐ２−ＯＨ、−Ｒ^Ｐ２−ＣＮ又は−Ｒ^Ｐ２−ＣＯＯＨである。Ｒ^Ｐ１は、炭素数１〜１０の１価の鎖状飽和炭化水素基、炭素数３〜２０の１価の脂肪族環状飽和炭化水素基又は炭素数６〜３０の１価の芳香族炭化水素基である。Ｒ^Ｐ２は、単結合、炭素数１〜１０の２価の鎖状飽和炭化水素基、炭素数３〜２０の２価の脂肪族環状飽和炭化水素基又は炭素数６〜３０の２価の芳香族炭化水素基である。但し、Ｒ^Ｐ１及びＲ^Ｐ２における鎖状飽和炭化水素基、脂肪族環状飽和炭化水素基及び芳香族炭化水素基の有する水素原子の一部又は全部はフッ素原子で置換されていてもよい。ｎ_Ｓは、０〜３の整数である。但し、ｎ_Ｓが２以上の場合、複数のＲ^Ｓは同一でも異なっていてもよい。）The structural unit (I) is preferably a structural unit (I-1) represented by the following formula (1-1).

(In the formula (1-1), R and R ^{1 to} R ³ have the same meanings as the formula (1). N _C is an integer of 1 to 4. R ^S represents —RP ¹ , —R. ^{P2 -O-R P1, -R P2} -CO-R P1, -R P2 -CO-oR P1, -R P2 -O-CO-R P1, -R P2 -OH, -R P2 -CN or -R a ^P2 -COOH ^{.R P1} represents a monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms, 1 monovalent aliphatic cyclic saturated hydrocarbon group or a C6-30 having 3 to 20 carbon atoms R ^P2 represents a single bond, a divalent chain saturated hydrocarbon group having 1 to 10 carbon atoms, a divalent aliphatic cyclic saturated hydrocarbon group having 3 to 20 carbon atoms, or R ^P2 is a divalent aromatic hydrocarbon group having 6 to 30 carbon atoms. However, a chain saturated hydrocarbon group in R ^P1 and R ^P2, alicyclic saturated hydrocarbon Good .n _S be some or all substituted by a fluorine atom of the hydrogen atoms included in the group and the aromatic hydrocarbon group is an integer of 0 to 3. However, if n _S is 2 or more, plural R ^S may be the same or different.)

  When the structural unit (I) has the specific structure having a monocyclic aliphatic hydrocarbon skeleton, molecules generated from the acid-dissociable group by the dissociation reaction are likely to be volatilized and hardly remain in the resist film. As a result, an increase in plasticity of the resist film can be suppressed and the acid diffusion length can be further optimized, so that the pattern-forming property and LWR performance of the radiation-sensitive resin composition are improved.

（式（１−２）中、Ｒ及びＲ^１〜Ｒ^３は、上記式（１）と同義である。Ｒ^Ｓは、−Ｒ^Ｐ１、−Ｒ^Ｐ２−Ｏ−Ｒ^Ｐ１、−Ｒ^Ｐ２−ＣＯ−Ｒ^Ｐ１、−Ｒ^Ｐ２−ＣＯ−ＯＲ^Ｐ１、−Ｒ^Ｐ２−Ｏ−ＣＯ−Ｒ^Ｐ１、−Ｒ^Ｐ２−ＯＨ、−Ｒ^Ｐ２−ＣＮ又は−Ｒ^Ｐ２−ＣＯＯＨである。Ｒ^Ｐ１は、炭素数１〜１０の１価の鎖状飽和炭化水素基、炭素数３〜２０の１価の脂肪族環状飽和炭化水素基又は炭素数６〜３０の１価の芳香族炭化水素基である。Ｒ^Ｐ２は、単結合、炭素数１〜１０の２価の鎖状飽和炭化水素基、炭素数３〜２０の２価の脂肪族環状飽和炭化水素基又は炭素数６〜３０の２価の芳香族炭化水素基である。但し、Ｒ^Ｐ１及びＲ^Ｐ２における鎖状飽和炭化水素基、脂肪族環状飽和炭化水素基及び芳香族炭化水素基の有する水素原子の一部又は全部はフッ素原子で置換されていてもよい。ｎ_Ｓは、０〜３の整数である。但し、ｎ_Ｓが２以上の場合、複数のＲ^Ｓは同一でも異なっていてもよい。）The structural unit (I) is preferably a structural unit (I-2) represented by the following formula (1-2).

(In the formula (1-2), R and ^R 1 to R ³ is as defined in the above formula (1) .R ^{S is, -R P1, -R P2 -O-} R P1, -R P2 -CO ^{-R P1, -R P2 -CO-oR} P1, -R P2 -O-CO-R P1, a ^-R P2 ^-OH, -R P2 -CN or ^-R P2 -COOH ^{.R P1} has a carbon number 1-10 monovalent chain saturated hydrocarbon group, a monovalent aliphatic cyclic saturated hydrocarbon group or a monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms having 3 to 20 carbon atoms .R ^P2 Is a single bond, a divalent chain saturated hydrocarbon group having 1 to 10 carbon atoms, a divalent aliphatic cyclic saturated hydrocarbon group having 3 to 20 carbon atoms, or a divalent aromatic carbon group having 6 to 30 carbon atoms. is a hydrogen group. However, organic chain saturated hydrocarbon group, aliphatic cyclic saturated hydrocarbon group and the aromatic hydrocarbon group for R ^P1 and R ^P2 That good .n _S be some or all substituted by a fluorine atom of the hydrogen atoms is an integer of 0 to 3. However, if n _S is 2 or more, plural structured R ^S are identical or different May be.)

  By making the structural unit (I) the specific structure, the dissociability of the acid-dissociable group is further increased, so that the PEB temperature can be further lowered, and the pattern-forming property of the radiation-sensitive resin composition can be reduced. , LWR performance, scum suppression and bridge defect suppression are further improved.

  The [A] polymer in the radiation-sensitive resin composition is preferably a polymer having a fluorine atom. [A] When the polymer has fluorine atoms, it tends to be unevenly distributed in the surface layer portion of the resist film due to high hydrophobicity due to the fluorine atoms. Accordingly, such a [A] polymer can exhibit a function as a water-repellent additive in, for example, an immersion exposure process. Therefore, according to the radiation-sensitive resin composition, the resist film and the immersion liquid can be used. Without requiring the separate formation of an upper layer to block the medium, a high dynamic contact angle is imparted to the resist film surface to improve water drainage performance, enabling the prevention of watermark remaining and high-speed scanning exposure. At the same time, elution of the acid generator and the like from the resist film can be suppressed. According to the radiation-sensitive resin composition, even when the PEB temperature is lower than the conventional temperature, the undissolved residue in the resist coating surface layer is greatly reduced, and as a result, scum suppression and bridge defect suppression are further improved. The increase in LWR caused by the occurrence of a bridge defect can be further suppressed.

  Moreover, it is preferable that the said [A] polymer in the said radiation sensitive resin composition is a polymer which further has the structural unit (VII) containing a lactone structure. [A] When the polymer further has the structural unit (VII), the affinity of the resist film formed from the radiation-sensitive resin composition to the alkaline developer can be increased. As a result, the pattern formability, LWR performance, scum suppression and bridge defect suppression of the radiation sensitive resin composition are further improved. Moreover, since the [A] polymer has the structural unit (VII), the adhesion of the resulting resist film to the substrate can be improved.

  The radiation-sensitive resin composition preferably further contains a [C] radiation-sensitive acid generator (hereinafter also referred to as “[C] acid generator”). The radiation sensitive resin composition can further improve the radiation sensitivity by further containing a [C] acid generator.

（式（１）中、Ｒは、水素原子、フッ素原子、メチル基又はトリフルオロメチル基である。Ｒ^Ｃは、Ｒ^ａと共に２価の脂肪族環状炭化水素基を形成する基である。この脂肪族環状炭化水素基の有する水素原子の一部又は全部は置換されていてもよい。Ｒ^ａは、炭素原子である。Ｒ^１〜Ｒ^３は、それぞれ独立して、水素原子、炭素数１〜１０の１価の鎖状飽和炭化水素基又は炭素数３〜２０の１価の脂肪族環状飽和炭化水素基である。この鎖状飽和炭化水素基及び脂肪族環状飽和炭化水素基の有する水素原子の一部又は全部は置換されていてもよい。但し、Ｒ^１〜Ｒ^３のいずれかが互いに結合して環状構造を形成していてもよい。）The polymer of the present invention has a structural unit (I) represented by the following formula (1).

(In Formula (1), R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R ^C is a group that forms a divalent aliphatic cyclic hydrocarbon group together with R ^a . Some or all of the hydrogen atoms of the aliphatic cyclic hydrocarbon group may be substituted, R ^a is a carbon atom, and R ^{1 to} R ³ are each independently a hydrogen atom or a carbon number of 1 To a monovalent chain saturated hydrocarbon group having from 10 to 10 or a monovalent aliphatic cyclic saturated hydrocarbon group having from 3 to 20 carbon atoms, hydrogen contained in the chain saturated hydrocarbon group and the aliphatic cyclic saturated hydrocarbon group. (Part or all of the atoms may be substituted, provided that any of R ^{1 to} R ³ may be bonded to each other to form a cyclic structure.)

  The polymer has a double bond adjacent cyclic hydrocarbon group as an acid dissociable group, which is very easy to dissociate. Therefore, according to the said polymer, it becomes possible to make PEB temperature in the case of resist pattern formation lower than the conventional temperature. Therefore, the said polymer is suitable as components, such as a radiation sensitive resin composition used for a lithography technique, for example.

（式（ｉ）中、Ｒは、水素原子、フッ素原子、メチル基又はトリフルオロメチル基である。Ｒ^Ｃは、Ｒ^ａと共に２価の脂肪族環状炭化水素基を形成する基である。この脂肪族環状炭化水素基の有する水素原子の一部又は全部は置換されていてもよい。Ｒ^ａは、炭素原子である。Ｒ^１〜Ｒ^３は、それぞれ独立して、水素原子、炭素数１〜１０の１価の鎖状飽和炭化水素基又は炭素数３〜２０の１価の脂肪族環状飽和炭化水素基である。この鎖状飽和炭化水素基及び脂肪族環状飽和炭化水素基の有する水素原子の一部又は全部は置換されていてもよい。但し、Ｒ^１〜Ｒ^３のいずれかが互いに結合して環状構造を形成していてもよい。）The compound of the present invention is represented by the following formula (i).

(In formula (i), R is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ^C is a group which forms a divalent aliphatic cyclic hydrocarbon group together with R ^a . Some or all of the hydrogen atoms of the aliphatic cyclic hydrocarbon group may be substituted, R ^a is a carbon atom, and R ^{1 to} R ³ are each independently a hydrogen atom or a carbon number of 1 To a monovalent chain saturated hydrocarbon group having from 10 to 10 or a monovalent aliphatic cyclic saturated hydrocarbon group having from 3 to 20 carbon atoms, hydrogen contained in the chain saturated hydrocarbon group and the aliphatic cyclic saturated hydrocarbon group. (Part or all of the atoms may be substituted, provided that any of R ^{1 to} R ³ may be bonded to each other to form a cyclic structure.)

  Since the compound of the present invention (hereinafter also referred to as “compound (i)”) has a structure represented by the above formula (i), it is suitable as a monomer compound incorporating the structural unit (I) in the polymer. Can be used.

  In the present specification, the “chain hydrocarbon group” means a hydrocarbon group that does not include a cyclic structure and is composed only of a chain structure, and includes both a linear hydrocarbon group and a branched hydrocarbon group. Shall be included. The “aliphatic cyclic hydrocarbon group” means a hydrocarbon group that includes only an aliphatic cyclic hydrocarbon structure as a ring structure and does not include an aromatic ring structure. However, it is not necessary to be constituted only by the structure of the aliphatic cyclic hydrocarbon, and a part thereof may include a chain structure. “Aromatic hydrocarbon group” means a hydrocarbon group containing an aromatic ring structure as a ring structure. However, it is not necessary to be composed only of an aromatic ring structure, and a part thereof may include a chain structure or an aliphatic cyclic hydrocarbon structure.

  As described above, the radiation-sensitive resin composition of the present invention can reduce the PEB temperature in the resist pattern formation process, and in addition, has a good shape and excellent LWR, and generates scum. In addition, it is possible to form a resist pattern in which the generation of bridge defects is suppressed. In addition, the amount of energy used in the manufacturing process can be reduced by lowering the PEB temperature.

It is a schematic diagram explaining the cross-sectional shape of a line and space pattern.

<Radiation sensitive resin composition>
The radiation sensitive resin composition of the present invention contains a [A] polymer and a [B] solvent. In addition, the radiation-sensitive resin composition contains [C] a radiation-sensitive acid generator, [D] other polymer having no structural unit (I), and [E] an acid diffusion controller as suitable components. You may do it. Furthermore, the said radiation sensitive resin composition may contain the other arbitrary component in the range which does not impair the effect of this invention.

  The radiation-sensitive resin composition may contain only a base polymer as a polymer component, and may contain a water-repellent additive in addition to the base polymer. The “base polymer” refers to a polymer that is a main component of a resist film formed from a radiation-sensitive resin composition, and preferably occupies 50% by mass or more based on the total polymer constituting the resist film. Refers to a polymer. The “water-repellent additive” is a polymer having a tendency to be unevenly distributed in the surface layer of the resist film to be formed by being contained in the radiation-sensitive resin composition. A polymer having higher hydrophobicity than the polymer serving as the base polymer tends to be unevenly distributed on the surface of the resist film, and can function as a water repellent additive. Since the radiation-sensitive resin composition contains a water-repellent additive, it can suppress elution of an acid generator and the like from the resist film, and the formed resist film surface exhibits a high dynamic contact angle. The resist coating surface can exhibit excellent water drainage characteristics. As a result, in the immersion exposure process, it is possible to perform high-speed scan exposure and suppress the occurrence of watermark defects and the like without the need to separately form an upper film for blocking the resist film surface and the immersion medium. be able to.

In the radiation sensitive resin composition, in order for the polymer to function well as a water repellent additive, the fluorine atom content of the water repellent additive is preferably higher than the fluorine atom content of the base polymer. If the fluorine atom content of the water-repellent additive is larger than that of the base polymer, the water-repellent additive is more likely to be unevenly distributed in the surface layer of the formed resist film. The characteristics resulting from the hydrophobicity of the polymer constituting the water-repellent additive are more effectively exhibited. In addition, this fluorine atom content rate (mass%) is computable from the structure of the polymer calculated | required by the measurement of < ¹³ > C-NMR.

  As an aspect of the radiation sensitive resin composition, as a polymer component, (1) [A] polymer as a base polymer, (2) [A] polymer as a base polymer and water repellent additive [A] polymer, (3) [A] polymer as base polymer and [D] polymer as water repellent additive, (4) [D] polymer and water repellent addition as base polymer The case where each contains the [A] polymer as an agent is mentioned. When the said radiation sensitive resin composition of said (2)-(4) contains both a base polymer and a water-repellent additive, [A] polymer is either a base polymer or a water-repellent additive. Even in the cases of (3) and (4) used only for the above, the effect of the present invention is sufficiently exerted, but the above (2) using the [A] polymer for both the base polymer and the water repellent additive. In this case, the pattern forming property, LWR performance, scum suppressing property and bridge defect suppressing property of the radiation sensitive resin composition which are the effects of the present invention can be further enhanced. Hereinafter, each structural component of the said radiation sensitive resin composition is demonstrated in order.

<[A] polymer>
[A] The polymer is a polymer having the structural unit (I). [A] The polymer may have the following structural units (II) to (IX) and other structural units in addition to the structural unit (I).

<Structural unit (I)>
The structural unit (I) is a structural unit represented by the above formula (1). The structural unit (I) has a double bond adjacent cyclic hydrocarbon group as an acid dissociable group. The “acid-dissociable group” refers to a group that substitutes a hydrogen atom in a polar functional group such as a hydroxyl group or a carboxyl group and dissociates in the presence of an acid. Such a polymer having an acid-dissociable group is insoluble or hardly soluble in alkali before the action of the acid, and the acid-dissociable group is eliminated by the action of an acid generated from the [C] acid generator described later. Then, it becomes alkali-soluble. Note that the polymer is “insoluble in alkali or hardly soluble in alkali” when the resist is developed under the alkali development conditions employed when a resist pattern is formed from a resist film formed using the radiation-sensitive resin composition. When a resist film having a film thickness of 100 nm using only such a polymer is developed in place of the film, it refers to the property that 50% or more of the initial film thickness of the resist film remains after development.

The double bond adjacent cyclic hydrocarbon group of the structural unit (I) has an acid dissociation property because the carbon atom (R ^a ) bonded to the ester group is the allylic position of the carbon-carbon double bond. Since the positive charge on the ^Ra carbon atom induced during the group dissociation reaction can be stabilized, the acid dissociable group dissociation reaction is very likely to occur. Therefore, according to the said radiation sensitive resin composition, PEB temperature can be lowered | hung from the conventional temperature, As a result, the influence of the spreading | diffusion of an acid is reduced and the resist pattern which has a favorable pattern shape and small LWR is reduced. It becomes possible to form. In addition, since the dissociation property of the acid dissociable group is very high, even when the PEB temperature is lowered, the polymer in the exposed portion is not required to increase the amount of acid generated by increasing the exposure amount, and the alkaline developer. Therefore, it is possible to form a resist pattern in which the occurrence of scum and bridge defects is suppressed.

In said formula (1), R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R ^C is a group that forms a divalent aliphatic cyclic hydrocarbon group together with R ^a . Some or all of the hydrogen atoms of the aliphatic cyclic hydrocarbon group may be substituted. R ^a is a carbon atom. R ^{1 to} R ³ are each independently a hydrogen atom, a monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms, or a monovalent aliphatic cyclic saturated hydrocarbon group having 3 to 20 carbon atoms. Some or all of the hydrogen atoms of the chain saturated hydrocarbon group and the aliphatic cyclic saturated hydrocarbon group may be substituted. However, any of R ^{1 to} R ³ may be bonded to each other to form a cyclic structure.

R ^C is a group that forms a divalent aliphatic cyclic hydrocarbon group together with R ^a . That is, the R ^a carbon atom to which R ^C is bonded has two bonds that are respectively bonded to the oxygen atom and the double bond carbon of the ester group.

Examples of the divalent aliphatic cyclic hydrocarbon group formed by R ^C together with R ^a include:
Monocyclic aliphatic saturated hydrocarbon groups such as cyclopropanediyl group, cyclobutanediyl group, cyclopentanediyl group, cyclohexanediyl group, cycloheptanediyl group, cyclooctanediyl group, cyclodecandidiyl group, cyclododecandiyl group;
Monocyclic aliphatic unsaturated hydrocarbon groups such as cyclobutenediyl, cyclopentenediyl, cyclohexenediyl, cyclodecenediyl, cyclododecenediyl, cyclopentadienediyl, cyclohexadienediyl, cyclodecadienediyl ;
Bicyclo [2.2.1] heptenediyl group, bicyclo [2.2.2] octanediyl group, tricyclo [5.2.1.0 ^2,6 ] decanediyl group, tricyclo [3.3.1.1 ^{3, 7} ] decandiyl group, tetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] a polycyclic aliphatic saturated hydrocarbon group such as a dodecanediyl group or an adamantanediyl group;
Bicyclo [2.2.1] heptenediyl group, bicyclo [2.2.2] octenediyl group, tricyclo [5.2.1.0 ^2,6 ] decenediyl group, tricyclo [3.3.1.1. ^3,7 ] decenediyl group, tetracyclo [6.2.1.1 ^3,6 . And a polycyclic aliphatic unsaturated hydrocarbon group such as 0 ^2,7 ] dodecenediyl group.

  Among these, from the viewpoint of improving the pattern formability and LWR performance of the radiation sensitive resin composition, a monocyclic aliphatic saturated hydrocarbon group and a monocyclic aliphatic unsaturated hydrocarbon group are preferable, and a monocyclic An aliphatic saturated hydrocarbon group is more preferable, and among them, a cyclopentanediyl group, a cyclohexanediyl group, a cycloheptanediyl group, and a cyclooctanediyl group are more preferable. The reason why the pattern-forming property and LWR performance of the radiation-sensitive resin composition are particularly improved by adopting these monocyclic aliphatic saturated hydrocarbon groups having 5 to 8 carbon atoms is as follows. It is conceivable that the diffusion length of. As described above, the reason why the acid diffusion length is shortened is not necessarily clear, but the low molecular weight substance generated from the acid dissociable group by the dissociation reaction is apt to volatilize, so that it is difficult to remain in the resist film. It is conceivable that the acid diffusion coefficient is reduced by lowering the plasticity of the resin. Among these, a cyclooctanediyl group is particularly preferable from the viewpoint of particularly high dissociability of the acid dissociable group.

In addition, the ease of dissociation of the acid-dissociable group is improved and the etching resistance of the resist film to be formed is improved, so that the polycyclic aliphatic saturated hydrocarbon group and the polycyclic aliphatic unsaturated hydrocarbon group Among them, a polycyclic aliphatic saturated hydrocarbon group is more preferable, and among them, a bicyclo [2.2.1] heptenediyl group, a bicyclo [2.2.2] octanediyl group, a tricyclo [5.2.1.0]. ^2,6 ] decanediyl group and adamantanediyl group are more preferred, and adamantanediyl group is particularly preferred.

The aliphatic cyclic hydrocarbon group formed by R ^C together with R ^a may have a substituent. As such substituents, for ^{example, -R P1, -R P2 -O-} R P1, -R P2 -CO-R P1, -R P2 -CO-OR P1, -R P2 -O-CO-R ^{P1, -R} P2 -OH, (collectively hereinafter these substituents also referred to as ^{"R S".) -R} P2 -CN or ^-R P2 -COOH and the like. Here, R ^P1 is a monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms, a monovalent aliphatic cyclic saturated hydrocarbon group having 3 to 20 carbon atoms, or a monovalent aromatic having 6 to 30 carbon atoms. Group hydrocarbon group. R ^P2 is a single bond, a divalent chain saturated hydrocarbon group having 1 to 10 carbon atoms, a divalent aliphatic cyclic saturated hydrocarbon group having 3 to 20 carbon atoms, or a divalent group having 6 to 30 carbon atoms. Is an aromatic hydrocarbon group. However, some or all of the hydrogen atoms of the chain saturated hydrocarbon group, the aliphatic cyclic saturated hydrocarbon group, and the aromatic hydrocarbon group of R ^P1 and R ^P2 may be substituted with fluorine atoms. The aliphatic cyclic hydrocarbon group may have one or more of the above substituents alone, or may have one or more of each of the above substituents.

Examples of the monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms represented by R ^{1 to} R ³ include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, and a heptyl group. Octyl group, decyl group and the like.
Examples of the monovalent aliphatic cyclic saturated hydrocarbon group having 3 to 20 carbon atoms represented by R ^{1 to} R ³ include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. Monocyclic aliphatic saturated hydrocarbon groups such as a group, cyclodecyl group, cyclododecyl group;
Bicyclo [2.2.2] octanyl group, tricyclo [5.2.1.0 ^2,6 ] decanyl group, tricyclo [3.3.1.1 ^3,7 ] decanyl group, tetracyclo [6.2.1 ^.1,3,6 . 0 ^2,7 ] dodecanyl group, polycyclic aliphatic saturated hydrocarbon group such as adamantyl group and the like.
Among these, from the viewpoint of ease of synthesis of the monomer compound giving the structural unit (I), a hydrogen atom and a monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms are preferable, and among them, a hydrogen atom Further, a methyl group and an ethyl group are more preferable, and a hydrogen atom is particularly preferable.

Examples of the substituent of the chain saturated hydrocarbon group and the aliphatic cyclic saturated hydrocarbon group represented by R ^{1 to} R ³ include an aliphatic cyclic hydrocarbon group formed by R ^C together with R ^a. Examples thereof include the same groups as those exemplified as the substituent.

Examples of the group containing a carbon-carbon double bond formed by bonding any of R ^{1 to} R ³ to each other to form a cyclic structure include a cyclopentenyl group, a cyclohexenyl group, a methylcyclopentenyl group, a methylcyclo A hexenyl group, a cyclopentylideneethenyl group, a cyclohexylideneethenyl group and the like can be mentioned. Among these, a cyclopentenyl group, a cyclohexenyl group, and a cyclopentylideneethenyl group are preferable from the viewpoint of ease of synthesis of the monomer compound that gives the structural unit (I).

  Examples of the structural unit (I) include structural units represented by the following formulas (1-1) to (1-6) (hereinafter also referred to as “structural units (I-1) to (I-6)”). ) And the like.

In the above formulas (1-1) to (1-6), R and R ^{1 to} R ³ have the same meaning as the above formula (1). R ^{S is, -R P1, -R P2 -O-} R P1, -R P2 -CO-R P1, -R P2 -CO-OR P1, -R P2 -O-CO-R P1, -R P2 - ^OH, it is a ^-R P2 -CN or ^-R P2 -COOH. R ^P1 is a monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms, a monovalent aliphatic cyclic saturated hydrocarbon group having 3 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms. It is a group. R ^P2 is a single bond, a divalent chain saturated hydrocarbon group having 1 to 10 carbon atoms, a divalent aliphatic cyclic saturated hydrocarbon group having 3 to 20 carbon atoms, or a divalent aroma having 6 to 30 carbon atoms. Group hydrocarbon group. Part or all of the hydrogen atoms of the chain saturated hydrocarbon group, the aliphatic cyclic saturated hydrocarbon group, and the aromatic hydrocarbon group in R ^P1 and R ^P2 may be substituted with a fluorine atom. n _S is an integer of 0 to 3. In the above formula (1-1), _{n C} is an integer of 1 to 4.

In the structural units (I-1) to (I-6), the aliphatic cyclic hydrocarbon group having a cycloalkane skeleton, an adamantane skeleton, a norbornane skeleton, a bicyclooctane skeleton, or a tricyclooctane skeleton is a hydrogen atom on the skeleton. The substituent R ^S for substituting may have a group listed as the substituent R ^S of the aliphatic cyclic hydrocarbon group formed by R ^C together with R ^a .

  Among these, the structural unit (I-1) and the structural unit (I-2) are preferable. [A] When the polymer has a structural unit (I-1) containing a cycloalkane skeleton, molecules generated from the acid-dissociable group are likely to volatilize due to the dissociation reaction, and thus the polymer hardly remains in the resist film. As a result, the acid diffusion length can be made more appropriate due to the decrease in plasticity of the resist film, so that the pattern-forming property and LWR performance of the radiation-sensitive resin composition are improved.

  Examples of the structural unit (I-1) include structural units represented by the following formulas (1-1-1) to (1-1-12).

  In the above formulas (1-1-1) to (1-1-12), R has the same meaning as the above formula (1).

  Among these, the acid diffusion length in the resist film becomes shorter, the pattern forming property and LWR performance of the radiation sensitive resin composition are further improved, and the monomer compound that gives the structural unit (I) can be easily synthesized. From the viewpoint of properties, structural units represented by the above formulas (1-1-1) to (1-1-4) are preferable, and a structural unit represented by the above formula (1-1-4) is more preferable. .

  In addition, when the polymer [A] has the structural unit (I-2), the adamantane skeleton is directly bonded to the ester group, and the dissociability of the acid dissociable group is further increased, so that the PEB temperature is further decreased. The pattern forming property, LWR performance, scum suppressing property and bridge defect suppressing property of the radiation sensitive resin composition are further improved. In the unexposed portion, the adamantane skeleton remains in the side chain even after alkali development, and the rigidity of the polymer is maintained. As a result, the resulting resist film can exhibit excellent etching resistance in the etching process after development.

  Examples of the structural unit (I-2) include structural units represented by the following formulas (1-2-1) to (1-2-9).

  In the above formulas (1-2-1) to (1-2-9), R represents a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

  Among these, from the viewpoint of the ease of dissociation of the acid dissociable group and the ease of synthesis of the monomer compound that gives the structural unit (I), the structure represented by the above formula (1-2-1) Units are preferred.

  Examples of the structural units (I-3) to (I-6) include structural units represented by the following formulas.

  Formulas (1-3-1) to (1-3-3), (1-4-1) to (1-4-3), (1-5-1) to (1-5-3) and In (1-6-1) to (1-6-3), R represents a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

  The content ratio of the structural unit (I) in the [A] polymer is 10 to 100 with respect to all structural units constituting the [A] polymer when the [A] polymer is a base polymer. Mol% is preferable, 20-70 mol% is more preferable, and 25-50 mol% is further more preferable. Moreover, when a [A] polymer turns into a water-repellent additive, 1-60 mol% is preferable, 3-40 mol% is more preferable, 5-35 mol% is further more preferable. By setting it as such a content rate, the pattern formation property and LWR performance of the said radiation sensitive resin composition can further be improved.

  The method for synthesizing the monomer compound (i) giving the structural unit (I) is as follows and can be synthesized according to the following scheme.

In the above formulas, ^R, R C, ^{R a} and ^R 1 to R ³ is as defined in the above formula (1).

  An allyl alcohol compound is obtained by reacting a cyclic ketone compound and an alkenyl magnesium bromide (Grignard reagent) in a solvent such as tetrahydrofuran. Compound (i) can be obtained by reacting this allyl alcohol compound with (meth) acryloyl chloride or the like in the presence of a base such as an organic amine.

  [A] In the case where the polymer is used as a water-repellent additive, etc., it is preferable to have the following structural units (II) to (IV) as the structural unit having a fluorine atom. In addition, even when the polymer [A] is used as a base polymer, by having these structural units, the hydrophilicity of the resist film formed from the radiation-sensitive resin composition can be appropriately adjusted. Can do.

<Structural unit (II)>
The structural unit (II) is a structural unit represented by the following formula (2). [A] Since the polymer has a structural unit (II), the hydrophobicity is increased, and the resist coating surface exhibits a high dynamic contact angle, so that elution of acid generators and the like from the resist coating is suppressed, The resist coating surface exhibits excellent water drainage characteristics. On the other hand, the Rf-CO group of the structural unit (II) is dissociated by hydrolysis in alkali development to generate a hydroxyl group, and an aliphatic cyclic hydrocarbon group is bonded to the ester group to be hydrolyzed. Therefore, the dynamic contact angle on the resist film surface is greatly reduced by alkali development. As a result, the wettability of the resist film surface to the developer and rinse liquid after alkali development is greatly improved, so that it is possible to suppress the occurrence of development defects in the resist film due to low cleaning efficiency with the rinse liquid. it can.

In said formula (2), R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. X is a single bond or a divalent linking group. R ^B is an optionally substituted carbon atoms from 3 to 30 of (n + 1) -valent alicyclic hydrocarbon group. Rf is a C1-C30 monovalent chain hydrocarbon group having 1-10 fluorine atoms or a C3-C30 monovalent aliphatic cyclic hydrocarbon having 1-10 fluorine atoms. It is a group. n is an integer of 1 to 3. However, when n is 2 or 3, a plurality of Rf may be the same or different.

  Examples of the divalent linking group represented by X include, for example, a divalent chain hydrocarbon group having 1 to 30 carbon atoms, a divalent aliphatic cyclic hydrocarbon group having 3 to 30 carbon atoms, and 6 carbon atoms. To 30 divalent aromatic hydrocarbon groups, and divalent groups obtained by combining these with ether groups, ester groups, carbonyl groups, imino groups, or amide groups. The divalent linking group represented by X may have a substituent.

Examples of the divalent chain hydrocarbon group having 1 to 30 carbon atoms include:
Chain saturated hydrocarbon groups such as methanediyl, ethanediyl, propanediyl, butanediyl, pentanediyl, hexanediyl, octanediyl, decandiyl, undecandiyl, hexadecandiyl, icosanediyl;
Ethenediyl group, propenediyl group, butenediyl group, pentenediyl group, hexenediyl group, octenediyl group, decenediyl group, undecenediyl group, hexadecenediyl group, icosendiyl group, ethynediyl group, propynediyl group, butynediyl group, octanediyl group, butadienediyl group, hexadiene group And chain unsaturated hydrocarbon groups such as alkynediyl groups such as octatrienediyl group.

Examples of the divalent aliphatic cyclic hydrocarbon group having 3 to 30 carbon atoms include:
Monocyclic saturated hydrocarbons such as cyclopropanediyl, cyclobutanediyl, cyclopentanediyl, cyclohexanediyl, cycloheptanediyl, cyclooctanediyl, cyclodecanediyl, methylcyclohexanediyl, ethylcyclohexanediyl Group;
Cyclobutenediyl group, cyclopentenediyl group, cyclohexenediyl group, cycloheptenediyl group, cyclooctenediyl group, cyclodecenediyl group, cyclopentadienediyl group, cyclohexadienediyl group, cyclooctadienediyl group, cyclodecadienediyl group Monocyclic unsaturated hydrocarbon groups such as
Bicyclo [2.2.1] heptanediyl group, bicyclo [2.2.2] octanediyl group, tricyclo [5.2.1.0 ^2,6 ] decanediyl group, tricyclo [3.3.1.1 ^{3, 7} ] decandiyl group, tetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] a polycyclic saturated hydrocarbon group such as a dodecanediyl group or an adamantanediyl group;
Bicyclo [2.2.1] heptenediyl group, bicyclo [2.2.2] octenediyl group, tricyclo [5.2.1.0 ^2,6 ] decenediyl group, tricyclo [3.3.1.1 ^3,7 ] Decenediyl group, tetracyclo [6.2.1.1 ^3,6 . And a polycyclic unsaturated hydrocarbon group such as 0 ^2,7 ] dodecenediyl group.

Examples of the divalent aromatic hydrocarbon group having 6 to 30 carbon atoms include:
Examples thereof include a phenylene group, a biphenylene group, a terphenylene group, a benzylene group, a phenyleneethylene group, a phenylenecyclohexylene group, and a naphthylene group.

  Examples of the divalent linking group represented by X include groups represented by the following formulas (X-1) to (X-6).

In the above formulas (X-1) to (X-6), R ^x1 each independently represents a divalent chain hydrocarbon group having 1 to 30 carbon atoms and a divalent aliphatic group having 3 to 30 carbon atoms. It is a cyclic hydrocarbon group or a C6-C30 bivalent aromatic hydrocarbon group. * Indicates a binding site that binds to ^{R B} in the formula (2).

Examples of the (n + 1) -valent aliphatic cyclic hydrocarbon group represented by R ^B include:
Monocyclic saturated hydrocarbons such as cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclodecane, methylcyclohexane, ethylcyclohexane;
Monocyclic unsaturated hydrocarbons such as cyclobutene, cyclopentene, cyclohexene, cycloheptene, cyclooctene, cyclodecene, cyclopentadiene, cyclohexadiene, cyclooctadiene, cyclodecadiene;
Bicyclo [2.2.1] heptane, bicyclo [2.2.2] octane, tricyclo [5.2.1.0 ^2,6 ] decane, tricyclo [3.3.1.1 ^3,7 ] decane, Tetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] polycyclic saturated hydrocarbons such as dodecane and adamantane;
Bicyclo [2.2.1] heptene, bicyclo [2.2.2] octene, tricyclo [5.2.1.0 ^2,6 ] decene, tricyclo [3.3.1.1 ^3,7 ] decene, Tetracyclo [6.2.1.1 ^3,6 . And a group obtained by removing (n + 1) hydrogen atoms from a cyclic hydrocarbon having 3 to 30 carbon atoms such as a polycyclic unsaturated hydrocarbon such as 0 ^2,7 ] dodecene. Among these, since the hydrolysis rate of the fluorine-containing group which is an alkali dissociable group is improved and the etching resistance of the formed resist film is improved, an (n + 1) -valent aliphatic having 4 to 30 carbon atoms. A polycyclic hydrocarbon group is preferable, a divalent or trivalent aliphatic polycyclic hydrocarbon group having 6 to 15 carbon atoms is more preferable, and a divalent aliphatic polycyclic hydrocarbon group having 8 to 12 carbon atoms. Is particularly preferred.

Also, R ^B may have a substituent. Examples of such a substituent include the same groups as the substituent R ^S in the structural unit (I). R ^B may have one or more of the above substituents alone, or may have one or more of each of the above substituents.

  In the group represented by Rf, the hydrocarbon group has 1 to 10 fluorine atoms. When the number of fluorine atoms contained in the group represented by Rf is in the above range, the hydrophobicity of the [A] polymer as the water repellent additive is moderate, and the radiation sensitive resin containing this The dynamic contact angle on the surface of the resist film formed from the composition is controlled so as to be highly balanced to such an extent that it has good water drainage and the occurrence of bubble defects is suppressed. As a result, occurrence of bubble defects can be reliably suppressed. When the number of fluorine atoms contained in the group represented by Rf exceeds 10, the hydrophobicity of the polymer [A] becomes too high, and the advancing contact angle on the surface of the resist film to be formed becomes too high. Is likely to occur. If the group represented by Rf does not have a fluorine atom, the hydrophobicity of the [A] polymer is insufficient, the receding contact angle on the surface of the resist film to be formed becomes low, and the group represented by Rf-CO. The hydrolyzability is reduced, and the decrease in hydrophobicity due to alkali development is small. The upper limit of the number of fluorine atoms contained in the group represented by Rf is preferably 9, more preferably 8, and even more preferably 7. On the other hand, the lower limit of the number of fluorine atoms is preferably 2, more preferably 3, and even more preferably 5.

  Examples of the monovalent chain hydrocarbon group having 1 to 30 carbon atoms and having 1 to 10 fluorine atoms represented by Rf include, for example, hydrogen atoms of a chain hydrocarbon group having 1 to 30 carbon atoms Examples include groups in which 1 to 10 are substituted with fluorine atoms. Examples of such a chain hydrocarbon group include a methyl group, an ethyl group, a 1-propyl group, a 2-propyl group, a 1-butyl group, a 2-butyl group, a 2- (2-methylpropyl) group, 1 -Pentyl group, 2-pentyl group, 3-pentyl group, 1- (2-methylbutyl) group, 1- (3-methylbutyl) group, 2- (2-methylbutyl) group, 2- (3-methylbutyl) group, Neopentyl group, 1-hexyl group, 2-hexyl group, 3-hexyl group, 1- (2-methylpentyl) group, 1- (3-methylpentyl) group, 1- (4-methylpentyl) group, 2- (2-methylpentyl) group, 2- (3-methylpentyl) group, 2- (4-methylpentyl) group, 3- (2-methylpentyl) group, 3- (3-methylpentyl) group, octyl group , Nonyl group, decyl group, dodecyl group, tetra Sill group, hexadecyl group, eicosanyl group and the like.

  Examples of the monovalent aliphatic cyclic hydrocarbon group having 3 to 30 carbon atoms having 1 to 10 fluorine atoms represented by Rf include, for example, a hydrogen atom of an aliphatic cyclic hydrocarbon group having 3 to 30 carbon atoms. Examples include groups in which 1 to 10 of them are substituted with fluorine atoms. Examples of such an aliphatic cyclic hydrocarbon group include a cyclopentyl group, a cyclopentylmethyl group, a 1- (1-cyclopentylethyl) group, a 1- (2-cyclopentylethyl) group, a cyclohexyl group, a cyclohexylmethyl group, 1- (1-cyclohexylethyl) group, 1- (2-cyclohexylethyl group), cycloheptyl group, cycloheptylmethyl group, 1- (1-cycloheptylethyl) group, 1- (2-cycloheptylethyl) group, 2 -Norbornyl group, 1-adamantyl group, 2-adamantyl group and the like.

  Among these, as the group represented by Rf, from the viewpoint of a large dynamic contact angle before development of the resist film surface to be formed, a C1-C4 perfluoroalkyl group, a C2-C5 mono A perfluoroalkylmethylene group and a C3-5 diperfluoroalkylmethylene group are preferred, and among them, a trifluoromethyl group and a perfluoropropyl group are particularly preferred.

  Examples of the structural unit (II) include structural units represented by the following formulas (2-1) to (2-4) (hereinafter also referred to as “structural units (II-1) to (II-4)”). Etc.).

In the above formulas (2-1) to (2-4), R, X, Rf and n are as defined in the above formula (2). R ^{S is, -R P1, -R P2 -O-} R P1, -R P2 -CO-R P1, -R P2 -CO-OR P1, -R P2 -O-CO-R P1, -R P2 - ^OH, it is a ^-R P2 -CN or ^-R P2 -COOH. R ^P1 is a monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms, a monovalent aliphatic cyclic saturated hydrocarbon group having 3 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms. It is a group. R ^P2 is a single bond, a divalent chain saturated hydrocarbon group having 1 to 10 carbon atoms, a divalent aliphatic cyclic saturated hydrocarbon group having 3 to 20 carbon atoms, or a divalent aroma having 6 to 30 carbon atoms. Group hydrocarbon group. However, a part or all of the hydrogen atoms of the chain saturated hydrocarbon group, the aliphatic cyclic saturated hydrocarbon group, and the aromatic hydrocarbon group in R ^P1 and R ^P2 may be substituted with fluorine atoms. n _S is an integer of 0 to 3.

In the structural units (II-1) to (II-4), the aliphatic cyclic hydrocarbon group having an adamantane skeleton, norbornane skeleton, bicyclooctane skeleton, or tricyclodecane skeleton is substituted to replace a hydrogen atom on the skeleton. The group R ^S may have a group listed as the substituent R ^S in the structural unit (I).

  Of these, the structural unit (II-1) is preferable. According to the radiation-sensitive resin composition containing the [A] polymer having the structural unit (II-1) as a water-repellent additive, a fluorine-containing group that is an alkali-dissociable group is bonded to the adamantane skeleton. Thus, the hydrolysis rate is high, the dynamic contact angle after the alkali development of the resist film is greatly reduced, and the etching resistance of the formed resist film is improved.

  In addition, as the structural unit (II-1), the structural unit represented by the following formulas (2-1a), (2-1b), and (2-1c) is an alkali dissociable group at a specific position in the adamantane structure. From the viewpoint of further increasing the hydrolysis rate and further decreasing the dynamic contact angle after alkali development of the resist film.

In the above formulas (2-1a), (2-1b) and (2-1c), R, X, Rf, R ^S and n _S have the same meaning as the above formula (2-1).

  In the structural unit represented by the above formula (2-1a), X is preferably a single bond or an alkanediyl group having 1 to 5 carbon atoms, and more preferably an alkanediyl group having 1 to 5 carbon atoms. Since X is an alkanediyl group having 1 to 5 carbon atoms, the alkali dissociable group is separated from the main chain of the [A] polymer by a certain distance, so that hydrolysis with an alkali developer is likely to occur, and the rate is Since it further increases, the dynamic contact angle is further reduced. The divalent linking group represented by X may have a hydroxyl group. Examples of the structural unit represented by the formula (2-1a) include structural units represented by the following formulas (2-1a-1) to (2-1a-9).

  In the above formulas (2-1a-1) to (2-1a-9), R is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

  In the above formulas (2-1b) and (2-1c), X is a single bond, an alkanediyl group having 1 to 5 carbon atoms, or a carbon number for the same reason as in the case of (2-1a) above. An alkanediyloxy group having 1 to 5 carbon atoms and an alkanediylcarbonyloxy group having 1 to 5 carbon atoms are preferable. The divalent linking group represented by X may have a hydroxyl group. Examples of the structural unit represented by the formula (2-1b) include structural units represented by the following formulas (2-1b-1) to (2-1b-9). Examples of the structural unit represented by the above formula (2-1c) include structural units represented by the following formulas (2-1c-1) to (2-1c-6).

  In the above formulas (2-1b-1) to (2-1b-9), R represents a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

  In the above formulas (2-1c-1) to (2-1c-6), R is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

  In these, the structural unit represented by the said Formula (2-1b-1) is preferable from a viewpoint of the synthetic | combination ease of the monomer which gives structural unit (II).

  Examples of the structural units represented by the structural units (II-2), (II-3), and (II-4) include the following formulas (2-2a), (2-2b), and (2-3a). , (2-4a) and the like.

  In the above formulas (2-2a), (2-2b), (2-3a) and (2-4a), R and Rf have the same meanings as the above formula (2).

  When the [A] polymer is a base polymer, the content ratio of the structural unit (II) in the [A] polymer is 0 to 30 mol% with respect to all the structural units constituting the [A] polymer. Is preferable, and 0 to 20 mol% is more preferable. By setting it as such a content rate, the affinity with respect to the alkaline developing solution of the resist film obtained can be improved. Moreover, when [A] a polymer is a water-repellent additive, 30-90 mol% is preferable and, as for the content rate of structural unit (II), 50-90 mol% is more preferable. By setting it as such a content rate, the resist film obtained can achieve the sufficient fall of the dynamic contact angle by image development with the high dynamic contact angle at the time of immersion exposure. In addition, the [A] polymer may have structural unit (II) individually by 1 type or in combination of 2 or more types.

<Structural unit (III)>
The structural unit (III) is a structural unit represented by the following formula (3). [A] When the polymer is used as a water-repellent additive, etc., since the [A] polymer further has a structural unit (III) containing a fluorine atom, the hydrophobicity is increased. It is possible to further improve the dynamic contact angle of the resist film surface formed from the product.

In said formula (3), R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. G is a single bond, an oxygen atom, a sulfur atom, —CO—O—, —SO ₂ —O—NH—, —CO—NH— or —O—CO—NH—. R ⁴ represents a monovalent chain hydrocarbon group having 1 to 6 carbon atoms having at least one fluorine atom or a monovalent aliphatic cyclic hydrocarbon group having 4 to 20 carbon atoms having at least one fluorine atom. It is.

Examples of the C1-C6 chain hydrocarbon group having at least one fluorine atom represented by R ⁴ include a trifluoromethyl group, a 2,2,2-trifluoroethyl group, and perfluoroethyl. Group, 2,2,3,3,3-pentafluoropropyl group, 1,1,1,3,3,3-hexafluoropropyl group, perfluoro n-propyl group, perfluoro i-propyl group, perfluoro Examples include n-butyl group, perfluoro i-butyl group, perfluoro t-butyl group, 2,2,3,3,4,4,5,5-octafluoropentyl group, perfluorohexyl group and the like.

Examples of the aliphatic cyclic hydrocarbon group having 4 to 20 carbon atoms having at least one fluorine atom represented by R ⁴ include a monofluorocyclopentyl group, a difluorocyclopentyl group, a perfluorocyclopentyl group, and a monofluoro group. Examples include cyclohexyl group, difluorocyclopentyl group, perfluorocyclohexylmethyl group, fluoronorbornyl group, fluoroadamantyl group, fluorobornyl group, fluoroisobornyl group, fluorotricyclodecyl group, fluorotetracyclodecyl group and the like.

  Examples of the monomer that gives the structural unit (III) include trifluoromethyl (meth) acrylic acid ester, 2,2,2-trifluoroethyl (meth) acrylic acid ester, and perfluoroethyl (meth) acrylic acid. Ester, perfluoro n-propyl (meth) acrylate, perfluoro i-propyl (meth) acrylate, perfluoro n-butyl (meth) acrylate, perfluoro i-butyl (meth) acrylate, Perfluoro t-butyl (meth) acrylic acid ester, 2- (1,1,1,3,3,3-hexafluoropropyl) (meth) acrylic acid ester, 1- (2,2,3,3,4 , 4,5,5-octafluoropentyl) (meth) acrylic acid ester, perfluorocyclohexylmethyl (meth) ) Acrylic acid ester, 1- (2,2,3,3,3-pentafluoropropyl) (meth) acrylic acid ester, monofluorocyclopentyl (meth) acrylic acid ester, difluorocyclopentyl (meth) acrylic acid ester, perfluoro Cyclopentyl (meth) acrylic acid ester, monofluorocyclohexyl (meth) acrylic acid ester, difluorocyclopentyl (meth) acrylic acid ester, perfluorocyclohexylmethyl (meth) acrylic acid ester, fluoronorbornyl (meth) acrylic acid ester, fluoro Adamantyl (meth) acrylate, fluorobornyl (meth) acrylate, fluoroisobornyl (meth) acrylate, fluorotricyclodecyl (meth) acrylate Fluoro tetracyclododecene decyl (meth) acrylic acid ester. Among these, 2,2,2-trifluoroethyl (meth) acrylate and perfluoro i-propyl (meth) acrylate are preferable.

  As the content ratio of the structural unit (III) in the [A] polymer, when the [A] polymer is a base polymer, 0 to 30 with respect to all the structural units constituting the [A] polymer. The mol% is preferable, and 0 to 20 mol% is more preferable. By setting it as such a content rate, the hydrophilicity degree of the resist film obtained can be adjusted more appropriately. Moreover, the affinity with respect to the alkaline developing solution of the resist film obtained can be improved. Moreover, when [A] polymer is a water-repellent additive, 30-90 mol% is preferable with respect to all the structural units which comprise [A] polymer, and 50-90 mol% is further more preferable. By setting it as such a content rate, the higher dynamic contact angle of the resist film surface can be expressed at the time of immersion exposure. In addition, the [A] polymer may have structural unit (III) individually by 1 type or in combination of 2 or more types.

<Structural unit (IV)>
The structural unit (IV) is a structural unit represented by the following formula (4). [A] In the case where the polymer is used as a hydrophobic additive, etc., since the hydrophobicity is increased by further having a structural unit (IV) containing a fluorine atom, a resist formed from the radiation-sensitive resin composition The dynamic contact angle on the coating surface can be further improved.

In said formula (4), R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R ⁵ is an (m + 1) -valent hydrocarbon group having 1 to 20 carbon atoms, and an oxygen atom, a sulfur atom, —NR′—, a carbonyl group, —CO—O—, or a terminal at the R ⁶ side of R ⁵ Also includes a structure in which —CO—NH— is bonded. However, R ′ is a hydrogen atom or a monovalent organic group. R ⁶ is a single bond, a divalent chain hydrocarbon group having 1 to 10 carbon atoms, or a divalent aliphatic cyclic hydrocarbon group having 4 to 20 carbon atoms. X ² is a divalent chain hydrocarbon group having 1 to 20 carbon atoms and having at least one fluorine atom. A is an oxygen atom, —NR ″ —, —CO—O— *, or —SO ₂ —O— *, where R ″ is a hydrogen atom or a monovalent organic group. * Indicates a binding site that binds to ^{R 7.} R ⁷ is a hydrogen atom or a monovalent organic group. m is an integer of 1-3. However, when m is 2 or 3, a plurality of R ⁶ , X ² , A and R ⁷ may be the same or different.

When R ⁷ is a hydrogen atom, it is preferable in that the solubility of [A] polymer in an alkaline developer can be improved.

Examples of the monovalent organic group represented by R ⁷ include an acid-dissociable group, an alkali-dissociable group, or a hydrocarbon group having 1 to 30 carbon atoms that may have a substituent. It is done.

When R ⁷ is an acid-dissociable group, the structural unit (IV) is dissociated by the action of an acid to generate a polar group. Therefore, when R ⁷ is an acid-dissociable group, it is preferable in that the solubility of the exposed portion in the exposure step in the resist pattern forming method described later can be increased.

The “alkali dissociable group” is a group that substitutes a hydrogen atom in a polar functional group such as a hydroxyl group or a carboxyl group, for example, in the presence of an alkali (for example, tetramethylammonium hydroxide 2. A group that dissociates in a 38% by weight aqueous solution). When R ⁷ is an alkali-dissociable group, the structural unit (IV) dissociates the alkali-dissociable group by the action of an alkali and generates a polar group. Therefore, when R ⁷ is an alkali-dissociable group, it is preferable in that the solubility in an alkali developer can be improved and the hydrophobicity of the resist film surface after development can be further reduced.

  Examples of the acid dissociable group include t-butoxycarbonyl group, tetrahydropyranyl group, tetrahydrofuranyl group, (thiotetrahydropyranylsulfanyl) methyl group, (thiotetrahydrofuranylsulfanyl) methyl group, alkoxy-substituted methyl group, alkylsulfanyl group. Examples include substituted methyl groups. In addition, as an alkoxy group (substituent) in an alkoxy substituted methyl group, a C1-C4 alkoxy group etc. are mentioned, for example. Moreover, as an alkyl group (substituent) in an alkylsulfanyl substituted methyl group, a C1-C4 alkyl group etc. are mentioned, for example. Moreover, as an acid dissociable group, group represented by the formula (Y-1) described in the term of the structural unit (V) mentioned later may be sufficient. Among these, when A is an oxygen atom or —NR ″ —, a t-butoxycarbonyl group or an alkoxy-substituted methyl group is preferable. When A is —CO—O—, a structural unit (V ) Is preferably a group represented by the formula (Y-1) described in the section.

  Examples of the alkali dissociable group include groups represented by the following formulas (W-1) to (W-5). Among these, when A is an oxygen atom or —NR ″ —, a group represented by the following formula (W-1) is preferable. When A is —CO—O—, the following formula (W -2) to (W-5) are preferred.

In the above formulas (W-1) and (W-5), Rf has the same meaning as in the above formula (2). In the formulas (W-2) and (W-3), R ⁴¹ is each independently a substituent. m ₁ is an integer from 0 to 5. m ₂ is an integer of 0-4. If the R ⁴¹ is plural, R ⁴¹ may be the same or different. In said formula (W-4), ^R42 and ^R43 are respectively independently a hydrogen atom or a C1-C10 alkyl group. However, R ⁴² and R ⁴³ may be bonded to each other to form a divalent aliphatic cyclic hydrocarbon group having 4 to 20 carbon atoms together with the carbon atom to which they are bonded.

Examples of the substituent represented by R ⁴¹ include the same groups as the substituent R ^S in the structural unit (I).

Examples of the divalent aliphatic cyclic hydrocarbon group formed by combining R ⁴² and R ⁴³ together with the carbon atom to which they are bonded include, for example, a cyclopentanediyl group, a methylcyclopentanediyl group, 2-ethylcyclohexane. Pentanediyl group, 3-ethylcyclopentanediyl group, cyclohexanediyl group, methylcyclohexanediyl group, 2-ethylcyclohexanediyl group, 3-ethylcyclohexanediyl group, cycloheptanediyl group, methylcycloheptanediyl group, 2-ethylcyclohexane A heptanediyl group, a 3-ethylcycloheptanediyl group, a norbornanediyl group, etc. are mentioned.

  Examples of the group represented by the formula (W-4) include a methyl group, an ethyl group, a 1-propyl group, a 2-propyl group, a 1-butyl group, a 2-butyl group, a 1-pentyl group, and 2- Pentyl group, 3-pentyl group, 1- (2-methylbutyl) group, 1- (3-methylbutyl) group, 2- (3-methylbutyl) group, neopentyl group, 1-hexyl group, 2-hexyl group, 3- Hexyl group, 1- (2-methylpentyl) group, 1- (3-methylpentyl) group, 1- (4-methylpentyl) group, 2- (3-methylpentyl) group, 2- (4-methylpentyl) ) Group, 3- (2-methylpentyl) group and the like. Among these, a methyl group, an ethyl group, a 1-propyl group, a 2-propyl group, a 1-butyl group, and a 2-butyl group are preferable.

Examples of the divalent chain-like hydrocarbon group having 1 to 20 carbon atoms and having at least one fluorine atom represented by ^{X 2,} for example, represented by the following formula (X2-1) ~ (X2-6) And the like.

X ² is preferably a group represented by the above formula (X2-1) when A is an oxygen atom. Moreover, when said A is -CO-O-, the group represented by said Formula (X2-2)-(X2-6) is preferable, and group represented by said Formula (X2-2) is further preferable.

In the above formula (4), m is an integer of 1 to 3. Accordingly, 1 to 3 R ⁷ are introduced into the structural unit (IV). When m is 2 or 3, a plurality of R ⁶ , R ⁷ , X ² and A may be the same or different. That is, when m is 2 or 3, the plurality of R ⁷ may have the same structure or different structures. When m is 2 or 3, a plurality of R ⁶ may be bonded to the same carbon atom of R ⁵ or may be bonded to different carbon atoms.

  Examples of the structural unit (IV) include structural units represented by the following formulas (4-1a) to (4-1c).

In the above formulas (4-1a) to (4-1c), R ⁸ is a divalent linear, branched or cyclic saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms. X ² , R ⁷ and m are as defined in the above formula (4). When m is 2 or 3, the plurality of X ² and R ⁷ may be the same or different.

  Examples of the monomer that gives the structural unit (IV) include compounds represented by the following formulas (4m-1) to (4m-6).

The formula (4m-1) ~ (4m -6) in, R and ^{R 7} are as defined above formula (4). However, if R ⁷ is plural, R ⁷ may be the same or different.

The monomer that gives the structural unit (IV) is represented by the above formula (4m-6) from the viewpoint of increasing the dynamic contact angle of the resist coating surface formed from the radiation-sensitive resin composition. Compounds are preferred. R in the above formula (4m-6) is preferably a methyl group. As the ^{R 7} in the formula (4m-6), an alkyl group, a phenyl group having 1 to 4 carbon atoms, a benzyl group is preferred, an ethyl group, t- butyl group, a benzyl group is more preferable.

  When the [A] polymer is a base polymer, the content ratio of the structural unit (IV) in the [A] polymer is 0 to 30 mol% with respect to all structural units constituting the [A] polymer. Is preferable, and 0 to 15 mol% is more preferable. The hydrophilicity degree of the resist film obtained by setting it as such a content rate can be adjusted more appropriately. Moreover, when a [A] polymer is a water-repellent additive, 30-100 mol% is preferable with respect to all the structural units which comprise a [A] polymer, and 50-100 mol% is further more preferable. By setting it as such a content rate, the resist film surface can exhibit a high dynamic contact angle. [A] The polymer may have one structural unit (IV) alone or in combination of two or more.

<Structural unit (V)>
[A] The polymer may further have a structural unit (V) represented by the following formula (5). However, the structural unit (V) excludes the structural unit (I). [A] When the polymer has the structural unit (V), the shape of the resulting resist pattern can be further improved.

  In said formula (5), R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Y is an acid dissociable group.

  The acid dissociable group represented by Y is preferably a group represented by the following formula (Y-1).

In the formula ^{(Y-1), R 9} , R 10 and ^{R 11} are each independently a monovalent aliphatic cyclic hydrocarbon group of the alkyl group or 4 to 20 carbon atoms having 1 to 4 carbon atoms . However, R ¹⁰ and R ¹¹ may be bonded to each other to form a divalent aliphatic cyclic hydrocarbon group having 4 to 20 carbon atoms together with the carbon atom to which they are bonded.

Examples of the alkyl group having 1 to 4 carbon atoms represented by R ^{9 to} R ¹¹ include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a 2-methylpropyl group, Examples include 1-methylpropyl group and t-butyl group.
Further, it is formed together with a monovalent aliphatic cyclic hydrocarbon group having 4 to 20 carbon atoms represented by R ^{9 to} R ¹¹ or a carbon atom to which R ¹⁰ and R ¹¹ are bonded to each other. Examples of the divalent aliphatic cyclic hydrocarbon group having 4 to 20 carbon atoms include a group having a bridged skeleton such as an adamantane skeleton and a norbornane skeleton; a group having a cycloalkane skeleton such as cyclopentane and cyclohexane; A group substituted with one or more of linear, branched or cyclic alkyl groups having 1 to 10 carbon atoms such as a methyl group, an ethyl group, an n-propyl group, an i-propyl group, etc. And a group having an aliphatic cyclic hydrocarbon skeleton. Among these, a group having a cycloalkane skeleton is preferable in that the shape of the resist pattern after development can be further improved.

  Examples of the structural unit (V) include structural units represented by the following formulas (5-1) to (5-4).

In said formula (5-1)-(5-4), R is synonymous with the said Formula (5). R < ⁹ > -R < ¹¹ > is synonymous with the said Formula (Y-1). Each r is independently an integer of 1 to 4.

Among these, the structural unit represented by the above formula (5-1) and the structural unit represented by the above formula (5-2) are preferable. Moreover, as R < ⁹ > in the said Formula (5-1) and (5-2), a methyl group, an ethyl group, and i-propyl group are preferable. As r in the formula (5-2), 1 or 4 is preferable from the viewpoint of easy dissociation of the acid dissociable group.

  As the content ratio of the structural unit (V) in the [A] polymer, the total structure constituting the [A] polymer is the case where the [A] polymer is a base polymer and a water repellent additive. 50 mol% or less is preferable with respect to the unit, 5 to 50 mol% is more preferable, and 10 to 40 mol% is particularly preferable. By setting it as such a content rate, the shape of the resist pattern obtained can be improved further. In addition, the [A] polymer may have a structural unit (V) individually by 1 type or in combination of 2 or more types.

<Structural unit (VI)>
[A] The polymer may have a structural unit (VI) having an alkali-soluble group. [A] The affinity of the resist film obtained by the polymer containing the structural unit (VI) with respect to the developer can be improved.

  The alkali-soluble group in the structural unit (VI) is preferably a functional group having a hydrogen atom having a pKa of 4 to 11 from the viewpoint of improving solubility in a developer. Examples of such functional groups include functional groups represented by the following formulas (6s-1) and (6s-2).

In said formula (6s-1), R < ¹² > is a C1-C10 hydrocarbon group which has at least 1 fluorine atom.

As the hydrocarbon group having 1 to 10 carbon atoms having at least one fluorine atom represented by R ¹² , some or all of the hydrogen atoms in the hydrocarbon group having 1 to 10 carbon atoms are substituted with fluorine atoms. There is no particular limitation as long as it is the same. For example, a trifluoromethyl group, a trifluoroethyl group, a pentafluoroethyl group, a nonafluorobutyl group and the like can be mentioned. Among these, a trifluoromethyl group and the like are preferable.

  Although it does not specifically limit as a monomer which gives the said structural unit (VI), A methacrylic acid ester, an acrylic acid ester, and (alpha) -trifluoroacrylic acid ester are preferable.

  Examples of the structural unit (VI) include structural units represented by the following formulas (6-1) and (6-2).

In the above formulas (6-1) and (6-2), R represents a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R < ¹² > is synonymous with the said Formula (6s-1). R ¹³ is a single bond or a divalent linear, branched or cyclic, saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms. In the above formula (6-2), R ¹⁴ is a divalent linking group. k is 0 or 1.

Examples of the divalent linking group represented by R ¹⁴ include the same groups as those exemplified as the divalent linking group X in the above formula (2).

  Examples of the structural unit (VI) include structural units represented by the following formulas (6-1a), (6-1b), and (6-2a) to (6-2e).

  In the above formulas (6-1a), (6-1b) and (6-2a) to (6-2e), R represents a hydrogen atom, a methyl group or a trifluoromethyl group.

    As the content ratio of the structural unit (VI) in the above [A] polymer, the total structure constituting the [A] polymer is the case where the [A] polymer is a base polymer and the water repellent additive. It is 50 mol% or less normally with respect to a unit, 5-30 mol% is preferable and 5-20 mol% is more preferable. By setting such a content ratio, it is possible to achieve a good balance between ensuring water repellency during immersion exposure and improving affinity for the developer during development. In addition, the [A] polymer may have structural unit (VI) individually by 1 type or in combination of 2 or more types.

<Structural unit (VII)>
[A] The polymer preferably has a structural unit (VII) containing a lactone structure. [A] Since the polymer has the structural unit (VII), the affinity of the resist film for the alkaline developer is improved. In addition, the adhesion of the resist film to the substrate can be improved.

  Examples of the structural unit (VII) include a structural unit represented by the following formula (7).

In said formula (7), R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R ^L1 is a single bond or a divalent linking group. R ^Lc is a monovalent organic group having a lactone structure.

Examples of the divalent linking group represented by R ^L1 include the same groups as those exemplified as the divalent linking group X in the structural unit (II).

Examples of the monovalent organic group having a lactone structure represented by R ^Lc include groups represented by the following formulas (Lc-1) to (Lc-6).

In the above formulas (Lc-1) to (Lc-6), R ^Lc1 is independently an oxygen atom or a methylene group. R ^Lc2 is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. n _Lc1 is independently 0 or 1. n _Lc2 is an integer of 0 to 3. * ^Represents a binding site that binds to R ^L1 in the formula (L-1). In addition, the groups represented by the formulas (Lc-1) to (Lc-6) may have a substituent.

Examples of the substituent of the groups represented by the formulas (Lc-1) to (Lc-6) include the same groups as the substituent R ^S in the structural unit (I).

  Examples of the structural unit (VII) include the structural units described in paragraphs [0054] to [0057] of JP2007-304537A and the structures described in paragraphs [0086] to [0088] of JP2008-088343A. Examples of the unit include structural units represented by the following formulas (7-1) to (7-12).

  In the above formulas (7-1) to (7-12), R represents a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

  Among these, the structural unit represented by the above formula (7-1) is preferable from the viewpoint of further improving the affinity of the resist film to the alkaline developer and the adhesion of the resist film to the substrate.

  In addition, the [A] polymer may have the said structural unit (VII) individually by 1 type or in combination of 2 or more types. Preferable monomers that give the structural unit (VII) include monomers described in paragraph [0043] of WO 2007/116664.

  As the content ratio of the structural unit (VII) in the above [A] polymer, when the [A] polymer is a base polymer, it is 5 to 75 mol with respect to all the structural units constituting the [A] polymer. % Is preferable, 15 to 65 mol% is more preferable, and 25 to 55 mol% is particularly preferable. If the content is less than 5 mol%, the resist may not be sufficiently adhered to the substrate and the pattern may be peeled off. On the other hand, when the content ratio exceeds 75 mol%, the contrast after dissolution is impaired, and the pattern shape may be deteriorated.

  Further, when the [A] polymer is a water repellent additive, the content ratio of the structural unit (VII) is usually 50 mol% or less with respect to all the structural units constituting the [A] polymer, 5-40 mol% is preferable and 5-20 mol% is more preferable. By setting it as such a content rate, the affinity with respect to the alkaline developing solution of the resist film surface can further be improved.

<Structural unit (VIII)>
[A] The polymer may have a structural unit (VIII) having a cyclic carbonate structure. [A] By having the structural unit (VIII), the polymer improves the affinity of the resist film for the alkaline developer. In addition, the adhesion of the resist film to the substrate can be improved. Examples of the structural unit (VIII) include a structural unit represented by the following formula (8).

  In said formula (8), R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. D is a trivalent chain hydrocarbon group having 1 to 30 carbon atoms, a trivalent aliphatic cyclic hydrocarbon group having 3 to 30 carbon atoms, or a trivalent aromatic hydrocarbon group having 6 to 30 carbon atoms. . D may have an oxygen atom, a carbonyl group, or —NH— in its skeleton. D may have a substituent.

Examples of the substituent that D may have include the substituent R ^S in the structural unit (I).

  Monomers that give structural units represented by the above formula (8) are described in, for example, Tetrahedron Letters, Vol. 27, no. 32 p. 3741 (1986), Organic Letters, Vol. 4, no. 15 p. It can be synthesized by a conventionally known method described in 2561 (2002).

  As the structural unit (VIII), structural units represented by the following formulas (8-1) to (8-22) are preferable.

  In said formula (8-1)-(8-22), R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

  [A] As a content ratio of the structural unit (VIII) in the polymer, when the [A] polymer is a base polymer, it is 5 to 75 mol% with respect to all the structural units constituting the [A] polymer. Is preferable, 15 to 65 mol% is more preferable, and 25 to 55 mol% is particularly preferable. If the content is less than 5 mol%, the adhesion between the resist film and the substrate is insufficient, and the pattern may be peeled off. On the other hand, when the content ratio exceeds 75 mol%, the contrast after dissolution is impaired, and the pattern shape may be deteriorated.

  When the [A] polymer is a water-repellent additive, the content ratio of the structural unit (VIII) is usually 50 mol% or less with respect to all the structural units constituting the [A] polymer, 5-40 mol% is preferable and 5-20 mol% is more preferable. By setting it as such a content rate, the affinity with respect to the alkaline developing solution of the resist film surface can further be improved.

<Structural unit (IX)>
The above [A] polymer may have a structural unit (IX) represented by the following formula (9). [A] When the polymer has the structural unit (IX), the affinity of the resist film for the developer can be improved.

In said formula (9), R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R ⁹¹ is a divalent linking group having no fluorine atom. R ⁹² is an alkali dissociable group. )

Examples of the divalent linking group having no fluorine atom represented by R ⁹¹ include those exemplified as the divalent linking group X in the above formula (2) but having no fluorine atom. It is done.

Examples of the alkali dissociable group represented by R ⁹² include groups represented by the above formulas (W-2) to (W-4).

  Examples of the structural unit (IX) include structural units represented by the following formulas (9-1) to (9-6).

  In said formula (9-1)-(9-6), R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

  [A] The content ratio of the structural unit (IX) in the polymer is such that [A] all structural units constituting the polymer, both when the polymer is a base polymer and when it is a water repellent additive On the other hand, it is usually 50 mol% or less, preferably 5 to 40 mol%, more preferably 5 to 20 mol%. By setting it as such a content rate, the affinity with respect to the alkaline developing solution of a resist film can be improved.

<Other structural units>
[A] The polymer may have a structural unit other than the above. Examples of the polymerizable unsaturated monomer that gives other structural units include monomers disclosed in paragraphs [0065] to [0085] of International Publication No. 2007 / 116664A.

  As the other structural units, structural units derived from 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, the following formula (o-1) Is preferable, and a structural unit derived from 2-hydroxyethyl (meth) acrylate is more preferable.

In said formula (o-1), R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R ^o1 is a divalent linking group.

Examples of the divalent linking group represented by R ^o1 include the same groups as those exemplified as the divalent linking group X in the above formula (2).

  Examples of the structural unit represented by the above formula (o-1) include structural units represented by the following formulas (o-1a) to (o-1h).

  In the above formulas (o-1a) to (o-1h), each R is independently a hydrogen atom, a methyl group or a trifluoromethyl group.

  [A] The content ratio of other structural units in the polymer is such that [A] the polymer is the base polymer and the water-repellent additive includes all the structural units constituting the [A] polymer. On the other hand, it is usually 50 mol% or less, preferably 5 to 40 mol%, more preferably 5 to 20 mol%. By setting it as such a content rate, the affinity with respect to the alkaline developing solution of a resist film can be improved.

  As described above, in the radiation-sensitive resin composition, the [A] polymer is preferably a polymer having a fluorine atom. [A] Since the polymer is a polymer having a fluorine atom, it has high hydrophobicity and can function as a water repellent additive. In addition, since this polymer has the structural unit (I), a resist pattern having a good pattern shape and a small LWR can be obtained even when the PEB temperature is lower than the conventional one. Since the undissolved residue of the water repellent additive unevenly distributed in the resist surface layer in the alkaline developer is suppressed, the occurrence of scum and bridge defects is greatly suppressed.

[A] Examples of the structural unit that gives a fluorine atom to the polymer include the structural units (II) to (IV), the structural unit (o-1), and the structural units (II) to (IX) in which R is fluorine. Those having an atom or trifluoromethyl group, those having a substituent containing a fluorine atom, those having a substituent of R ^{C in} the structural unit (I) having a fluorine atom, and those in the structural units (I) to (IX) And those in which R is a fluorine atom or a trifluoromethyl group.

  Further, as described above, in the radiation sensitive resin composition, the [A] polymer is preferably a polymer having a structural unit (VII) containing a lactone structure. [A] Since the polymer has a structural unit (VII) containing a lactone structure, the affinity of the resist film with an alkaline developer is increased, so that the remaining undissolved polymer in the exposed area is further reduced. According to the radiation sensitive resin composition, the occurrence of scum and bridge defects can be further suppressed. In addition, due to the suppression of the occurrence thereof, the pattern formability and LWR performance of the radiation sensitive resin composition can be further improved. Such polymers are suitable both as a base polymer and as a water repellent additive. Moreover, the adhesiveness to the board | substrate of the resist film formed from the said radiation sensitive resin composition improves because a [A] polymer has a structural unit (VII). Therefore, such [A] polymer is more suitable as a base polymer.

  The radiation-sensitive resin composition particularly preferably contains both the polymer having a fluorine atom and the polymer having a structural unit (VII) as the [A] polymer. When the radiation-sensitive resin composition contains both of the above two polymers, the [A] polymer having the structural unit (VII) is the base polymer, and the [A] polymer having a fluorine atom is water-repellent. Functions as an additive. Both of these components have the property that the acid dissociable groups are sufficiently dissociated even when the PEB temperature is lowered, so that the remaining resist film in the alkaline developer is further suppressed. Is done. As a result, the pattern-forming property, LWR performance, scum suppression and bridge defect suppression of the radiation-sensitive resin composition can be particularly improved.

  As content of [A] polymer in the said radiation sensitive resin composition, with respect to the total polymer which combined [A] polymer and other polymer contained as needed, [A] polymer, Usually, it is 2 mass% or more, 20-100 mass% is preferable, and 30-100 mass% is more preferable. [A] If the content of the polymer is less than 2% by mass, the pattern shape or the like of the resist pattern obtained from the radiation-sensitive resin composition may be deteriorated.

<[A] Polymer Synthesis Method>
[A] The polymer can be synthesized according to a conventional method such as radical polymerization. For example, a method in which a solution containing a monomer and a radical initiator is dropped into a reaction solvent or a solution containing the monomer to cause a polymerization reaction; a solution containing the monomer and a solution containing the radical initiator; A method in which a polymerization reaction is carried out by dropping each into a solution containing a reaction solvent or a monomer; a plurality of types of solutions containing each monomer and a solution containing a radical initiator are reacted separately. It can synthesize | combine by the method etc. which are dripped at the solution containing a solvent or a monomer, and making it polymerize.

  In addition, when making a monomer solution drop and react with respect to a monomer solution, as monomer amount in the dropped monomer solution, it is 30 with respect to the monomer total amount used for superposition | polymerization. It is preferably at least mol%, more preferably at least 50 mol%, still more preferably at least 70 mol%.

  What is necessary is just to determine the reaction temperature in these methods suitably with initiator seed | species, Usually, it is 30 to 150 degreeC, 40 to 150 degreeC is preferable and 50 to 140 degreeC is further more preferable. The dropping time varies depending on the reaction temperature, the type of initiator, the monomer to be reacted, etc., but is usually 30 minutes to 8 hours, preferably 45 minutes to 6 hours, and more preferably 1 hour to 5 hours. . Further, the total reaction time including the dropping time varies depending on the conditions as well as the dropping time, but is usually 30 minutes to 12 hours, preferably 45 minutes to 12 hours, and more preferably 1 hour to 10 hours.

  Examples of the radical initiator used in the polymerization include azobisisobutyronitrile (AIBN), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), and 2,2′-azobis. Azo radical initiators such as (2-cyclopropylpropionitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), dimethyl 2,2′-azobis (2-methylpropionate); benzoyl And peroxide radical initiators such as peroxide, t-butyl hydroperoxide, cumene hydroperoxide, and the like. Of these, dimethyl 2,2'-azobis (2-methylpropionate) is preferred. These radical initiators can be used alone or in admixture of two or more.

  As the polymerization solvent, any solvent other than a solvent that inhibits polymerization (nitrobenzene having a polymerization inhibiting effect, mercapto compound having a chain transfer effect, etc.) and capable of dissolving the above monomers can be used. Examples thereof include alcohols, ethers, ketones, amides, esters / lactones, nitriles, and mixed solvents thereof. These solvents can be used alone or in admixture of two or more.

  The polymer obtained by the polymerization reaction is preferably recovered by a reprecipitation method. That is, after the polymerization reaction is completed, the polymer is recovered as a powder by introducing the polymerization solution into a reprecipitation solvent. As the reprecipitation solvent, alcohols, alkanes and the like can be used alone or in admixture of two or more. In addition to the reprecipitation method, the polymer can be recovered by removing low molecular components such as monomers and oligomers by a liquid separation operation, a column operation, an ultrafiltration operation, or the like.

  [A] The weight average molecular weight (Mw) in terms of polystyrene by gel permeation chromatography (GPC) of the polymer is preferably 3,000 to 300,000 when the [A] polymer is a base polymer, 000 to 200,000 is more preferable, and 4,000 to 100,000 is more preferable. If the Mw is less than 3,000, the heat resistance of the resulting resist film may be reduced. On the other hand, if Mw exceeds 300,000, the developability of the resulting resist film may be reduced.

  When the [A] polymer is a water repellent additive, the Mw of the [A] polymer is preferably 1,000 to 50,000, more preferably 1,000 to 40,000, and 1,000. ˜30,000 is particularly preferred. [A] If the Mw of the polymer is less than 1,000, a resist film having a sufficient dynamic contact angle may not be obtained. On the other hand, if the Mw of the [A] polymer exceeds 50,000, the developability of the resist film may be lowered.

  Further, the ratio (Mw / Mn) of Mw to the number average molecular weight (Mn) in terms of polystyrene by GPC of the [A] polymer is the water repellent additive when [A] the polymer is a base polymer. In any case, it is usually 1.0 to 5.0, preferably 1.0 to 4.0, and more preferably 1.0 to 2.0.

  In this specification, Mw and Mn are Tosoh GPC columns (2 G2000HXL, 1 G3000HXL, 1 G4000HXL), the flow rate is 1.0 mL / min, the elution solvent is tetrahydrofuran, and the column temperature is Measurement was performed by GPC using monodisperse polystyrene as a standard under analysis conditions of 40 ° C.

<[B] Solvent>
The radiation sensitive resin composition of the present invention contains a [B] solvent. As the [B] solvent that can be used for the preparation of the radiation-sensitive resin composition, a solvent that uniformly dissolves or disperses each component and does not react with each component is preferably used. [B] Examples of the solvent include alcohols, ethers, diethylene glycol alkyl ethers, ethylene glycol alkyl ether acetates, propylene glycol monoalkyl ethers, propylene glycol monoalkyl ether acetates, propylene glycol monoalkyl ether propionate. , Aromatic hydrocarbons, ketones, esters and the like.

Examples of alcohols include benzyl alcohol and diacetone alcohol;
Examples of ethers include cyclic ethers such as tetrahydrofuran and dioxane; dialkyl ethers such as diisopropyl ether, di n-butyl ether, di n-pentyl ether, diisopentyl ether, and di n-hexyl ether;
Examples of diethylene glycol alkyl ethers include diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, and diethylene glycol ethyl methyl ether;
Examples of ethylene glycol alkyl ether acetates include methyl cellosolve acetate, ethyl cellosolve acetate, ethylene glycol monobutyl ether acetate, and ethylene glycol monoethyl ether acetate;
Examples of propylene glycol monoalkyl ethers include propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether;
Examples of propylene glycol monoalkyl ether acetates include propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate;
Examples of propylene glycol monoalkyl ether propionates include propylene glycol monomethyl ether propionate, propylene glycol monoethyl ether propionate, propylene glycol monopropyl ether propionate, propylene glycol monobutyl ether propionate, and the like;
Examples of aromatic hydrocarbons include toluene and xylene;
Examples of ketones include methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, 2-heptanone, 4-hydroxy-4-methyl-2-pentanone, and the like;
Examples of the esters include methyl acetate, ethyl acetate, propyl acetate, i-propyl acetate, butyl acetate, ethyl 2-hydroxypropionate, methyl 2-hydroxy-2-methylpropionate, 2-hydroxy-2-methylpropion Ethyl acetate, methyl hydroxyacetate, ethyl hydroxyacetate, butyl hydroxyacetate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, methyl 3-hydroxypropionate, ethyl 3-hydroxypropionate, protyl 3-hydroxypropionate, 3- Butyl hydroxypropionate, methyl 2-hydroxy-3-methylbutanoate, methyl methoxyacetate, ethyl methoxyacetate, propyl methoxyacetate, butyl methoxyacetate, methyl ethoxyacetate, ethyl ethoxyacetate, propyl ethoxyacetate, etho Butyl butyl acetate, methyl propoxyacetate, ethyl propoxyacetate, propylpropoxyacetate, butyl propoxyacetate, methyl butoxyacetate, ethyl butoxyacetate, propylbutoxyacetate, butylbutoxyacetate, methyl 2-methoxypropionate, ethyl 2-methoxypropionate, Examples include propyl 2-methoxypropionate, butyl 2-methoxypropionate, methyl 2-ethoxypropionate, ethyl 2-ethoxypropionate and the like.

  Among these, as the solvent [B], ethers, diethylene glycol alkyls are preferred from the viewpoints of excellent solubility or dispersibility, non-reactivity with each component, and ease of film formation. Ethers, ethylene glycol alkyl ether acetates, propylene glycol monoalkyl ethers, propylene glycol monoalkyl ether acetates, ketones, esters are preferred, diethylene glycol diethyl ether, diethylene glycol ethyl methyl ether, methyl cellosolve acetate, ethyl cellosolve acetate, Propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether Teracetate, cyclohexanone, propyl acetate, i-propyl acetate, butyl acetate, ethyl 2-hydroxypropionate, methyl 2-hydroxy-2-methylpropionate, ethyl 2-hydroxy-2-methylpropionate, methyl lactate, ethyl lactate Propyl lactate, butyl lactate, methyl 2-methoxypropionate and ethyl 2-methoxypropionate are more preferred, and propylene glycol monomethyl ether acetate and cyclohexanone are more preferred. These solvents can be used alone or in combination.

  In addition, when applying the radiation sensitive resin composition to a large glass substrate by a slit coating method, the drying process time is shortened, and at the same time, from the viewpoint of further improving the coating property (suppressing coating unevenness), these Among the solvents, ethers are preferable, dialkyl ethers are more preferable, diisopropyl ether, di n-butyl ether, di n-pentyl ether, diisopentyl ether, di n-hexyl ether are further preferable, and diisopentyl ether is most preferable. .

  In addition to the above-mentioned solvent [B], benzyl ethyl ether, dihexyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, acetonyl acetone, isophorone, caproic acid, caprylic acid, 1-octanol as necessary , 1-nonanol, benzyl alcohol, benzyl acetate, ethyl benzoate, diethyl oxalate, diethyl maleate, phenyl cellosolve acetate, carbitol acetate, and the like can also be used in combination.

  When preparing the radiation sensitive resin composition in a solution or dispersion state, the proportion of components other than the solvent [B] in the solution (that is, the total amount of the [A] polymer and other optional components) is used. Although it can set arbitrarily according to the objective, desired film thickness, etc., Preferably it is 5-50 mass%, More preferably, it is 10-40 mass%, More preferably, it is 15-35 mass%.

<[C] acid generator>
The [C] acid generator generates an acid upon exposure, and the acid dissociates an acid dissociable group present in the polymer such as the [A] polymer and [D] another polymer. As a result, the exposed portion of the resist film becomes soluble in the developer. [C] The content of the acid generator in the radiation-sensitive resin composition is an acid generator (hereinafter also referred to as “[C] acid generator” as appropriate) which is a compound as described later, The form of the acid generating group incorporated as part of the A] polymer or [D] other polymer, or both forms thereof may be used.

  Examples of the [C] acid generator suitably used in the radiation-sensitive resin composition include onium salt compounds such as sulfonium salts, iodonium salts, tetrahydrothiophenium salts, N-sulfonyloxyimide compounds, and organic halogens. Examples thereof include sulfone compounds such as compounds and disulfones and diazomethane sulfones.

  Examples of such a [C] acid generator include compounds described in paragraphs [0080] to [0113] of JP-A-2009-134088.

In addition, as [C] acid generator,
As the iodonium salt, for example,
Diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, diphenyliodonium perfluoro-n-octanesulfonate, bis (4-t-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-t-butylphenyl) iodonium Nonafluoro-n-butanesulfonate, bis (4-t-butylphenyl) iodonium perfluoro-n-octanesulfonate, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluoro-n-butanesulfonate, triphenylsulfonium perfluoro- n-Octanesulfonate, cyclohexyl, 2-oxocyclohexyl, methylsulfonium trifluoro Tan sulfonate, dicyclohexyl-2-oxo-cyclohexyl trifluoromethane sulfonate, 2-oxo-cyclohexyl dimethyl sulfonium trifluoromethane sulfonate, 4-hydroxy-1-naphthyl dimethyl sulfonium trifluoromethane sulfonate and the like.

As the tetrahydrothiophenium salt, for example,
4-hydroxy-1-naphthyltetrahydrothiophenium trifluoromethanesulfonate, 4-hydroxy-1-naphthyltetrahydrothiophenium nonafluoro-n-butanesulfonate, 4-hydroxy-1-naphthyltetrahydrothiophenium perfluoro-n- Octanesulfonate, 1- (1-naphthylacetomethyl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (1-naphthylacetomethyl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, 1- (1-naphthylacetomethyl) Tetrahydrothiophenium perfluoro-n-octanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium trifluoromethanesulfonate, 1- 3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium perfluoro-n-octanesulfonate, etc. Can be mentioned.

Examples of the N-sulfonyloxyimide compound include:
Trifluoromethanesulfonylbicyclo [2.2.1] hept-5-ene-2,3-dicarbodiimide, nonafluoro-n-butanesulfonylbicyclo [2.2.1] hept-5-ene-2,3-dicarbodiimide , Perfluoro-n-octanesulfonylbicyclo [2.2.1] hept-5-ene-2,3-dicarbodiimide, N-hydroxysuccinimide trifluoromethanesulfonate, N-hydroxysuccinimide nonafluoro-n- Examples include butane sulfonate, N-hydroxysuccinimide perfluoro-n-octane sulfonate, 1,8-naphthalenedicarboxylic acid imide trifluoromethane sulfonate, and the like.

  [C] As the acid generator, an onium salt compound is preferable, a sulfonium salt is more preferable, triphenylsulfonium perfluoroalkanesulfonate is more preferable, and triphenylsulfonium nonafluorobutanesulfonate is particularly preferable.

  [C] Acid generators can be used alone or in admixture of two or more. The content of the [C] acid generator is included in the radiation-sensitive resin composition when the [C] acid generator is a [C] acid generator from the viewpoint of ensuring sensitivity and developability as a resist. 0.1-30 mass parts is preferable with respect to 100 mass parts of total amounts of the polymer to be produced, and 0.1-20 mass parts is more preferable. If the content of the acid generator is less than 0.1 parts by mass, the sensitivity and developability of the radiation-sensitive resin composition tend to decrease, whereas if the content exceeds 30 parts by mass, the radiation-sensitive property is concerned. There is a tendency that the transparency of the resin composition with respect to radiation is lowered and it becomes difficult to obtain a rectangular resist pattern.

<[D] Other polymer>
The radiation-sensitive resin composition may contain [D] another polymer having no structural unit (I) as a polymer component, in addition to the [A] polymer. [D] Examples of the other polymer include a polymer having at least one structural unit selected from the group consisting of the structural unit (II) to the structural unit (IX) and the other structural unit. .

<[E] Acid diffusion controller>
The radiation sensitive resin composition of this invention can contain an [E] acid diffusion control body as a suitable component. [E] When an acid diffusion control body is contained, the pattern formability and dimensional fidelity of the radiation-sensitive resin composition can be improved. [E] As the acid diffusion controller, for example, a compound represented by the following formula (10) (hereinafter, also referred to as “nitrogen-containing compound (I)”), a compound having two nitrogen atoms in the same molecule ( Hereinafter, also referred to as “nitrogen-containing compound (II)”), a compound having 3 or more nitrogen atoms (hereinafter also referred to as “nitrogen-containing compound (III)”), an amide group-containing compound, a urea compound, a nitrogen-containing complex. A ring compound etc. are mentioned. [E] The content of the acid diffusion controller in the radiation-sensitive resin composition is a compound as described below (hereinafter also referred to as “[E] acid diffusion controller” as appropriate). It may be in the form of an acid diffusion control group incorporated as part of a polymer such as a polymer or [D] other polymer, or both of these forms.

In the above formula (10), R ^{15 to} R ¹⁷ are each independently a hydrogen atom, an optionally substituted linear, branched or cyclic alkyl group, aryl group or aralkyl group.

  Examples of the nitrogen-containing compound (I) include monoalkylamines such as n-hexylamine; dialkylamines such as di-n-butylamine; trialkylamines such as triethylamine; aromatic amines such as aniline. Can be mentioned.

  Examples of the nitrogen-containing compound (II) include ethylenediamine, N, N, N ′, N′-tetramethylethylenediamine, and the like.

  Examples of the nitrogen-containing compound (III) include polymers of polyethyleneimine, polyallylamine, dimethylaminoethylacrylamide, and the like.

  Examples of the amide group-containing compound include formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, propionamide, benzamide, pyrrolidone, N-methylpyrrolidone and the like. Can be mentioned.

  Examples of the urea compound include urea, methylurea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea, 1,3-diphenylurea, tributylthiourea and the like. .

Examples of the nitrogen-containing heterocyclic compound include pyridines such as pyridine and 2-methylpyridine; aromatic heterocyclic compounds such as compounds containing multiple nitrogen atoms such as pyrazine, pyrazole and imidazole,
Aliphatic heterocyclic compounds such as pyrrolidine, piperidine, piperazine and the like can be mentioned.

  Moreover, the compound which has an acid dissociable group can also be used as said nitrogen-containing organic compound. Examples of the nitrogen-containing organic compound having such an acid dissociable group include N- (t-butoxycarbonyl) piperidine, N- (t-butoxycarbonyl) imidazole, N- (t-butoxycarbonyl) benzimidazole, N -(T-butoxycarbonyl) -2-phenylbenzimidazole, N- (t-butoxycarbonyl) di-n-octylamine, N- (t-butoxycarbonyl) diethanolamine, N- (t-butoxycarbonyl) dicyclohexylamine, N- (t-butoxycarbonyl) diphenylamine, N- (t-butoxycarbonyl) -4-hydroxypiperidine and the like can be mentioned. Among these, N- (t-butoxycarbonyl) -4-hydroxypiperidine and N- (t-butoxycarbonyl) piperidine are preferable, and N- (t-butoxycarbonyl) -4-hydroxypiperidine is more preferable.

Moreover, as an [E] acid spreading | diffusion controlling agent, the compound represented by following formula (11) can also be used besides the said compound.
X ⁺ Z ^- (11)

In the above formula (11), X ⁺ is a cation represented by the following formula (11-1-1) or (11-1-2). Z ^{- is,} OH ^-, R D1 -COO ^- anion represented ^by, R D1 -SO ₃ ^- anionic or ^R D1 ^-N represented by - is an anion represented by _-SO 2 ^{-R D2.} However, R ^D1 represents an optionally substituted alkyl group, a monovalent aliphatic cyclic hydrocarbon group, or an aryl group. R ^D2 is an alkyl group or a monovalent aliphatic cyclic hydrocarbon group in which some or all of the hydrogen atoms are substituted with fluorine atoms.

In formula (11-1-1) and formula (11-1-2), R ^{D3 to} R ^D7 each independently represent a hydrogen atom, an alkyl group, an alkoxy group, a hydroxyl group, or a halogen atom.

  The above compound is used as an acid diffusion controller (hereinafter also referred to as “photodegradable acid diffusion controller”) that loses acid diffusion controllability by being decomposed by exposure. By containing this compound, the acid diffuses in the exposed area, and the acid diffusion is controlled in the unexposed area, so that the contrast between the exposed area and the unexposed area is excellent (that is, the boundary between the exposed area and the unexposed area). Therefore, the radiation sensitive resin composition is effective in improving LWR and MEEF (Mask Error Enhancement Factor).

R ^{D3 to} R ^D5 are preferably a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom because of the effect of reducing the solubility of the compound in a developer. Moreover, as said R ^<D6> and R ^<D7> , a hydrogen atom, an alkyl group, and a halogen atom are preferable.

R ^D1 in Z ⁻ is preferably an aliphatic cyclic hydrocarbon group or an aryl group because of the effect of reducing the solubility of the compound in a developer.

Examples of the optionally substituted alkyl group represented by R ^D1 include a hydroxyalkyl group having 1 to 4 carbon atoms such as a hydroxymethyl group; an alkoxy group having 1 to 4 carbon atoms such as a methoxy group; a cyano group A group having one or more substituents such as a cyanoalkyl group having 2 to 5 carbon atoms such as a cyanomethyl group; Among these, a hydroxymethyl group, a cyano group, and a cyanomethyl group are preferable.

Examples of the optionally substituted aliphatic cyclic hydrocarbon group represented by R ^D1 include cycloalkane skeletons such as hydroxycyclopentane, hydroxycyclohexane, and cyclohexanone; 1,7,7-trimethylbicyclo [2.2 .1] Monovalent groups derived from aliphatic cyclic hydrocarbons such as a bridged aliphatic cyclic hydrocarbon skeleton such as heptan-2-one (camphor). Among these, a group derived from 1,7,7-trimethylbicyclo [2.2.1] heptan-2-one is preferable.

Examples of the ^optionally substituted aryl group represented by R ^D1 include a phenyl group, a benzyl group, a phenylethyl group, a phenylpropyl group, a phenylcyclohexyl group, and the like. The thing substituted by the cyano group etc. is mentioned. Among these, a phenyl group, a benzyl group, and a phenylcyclohexyl group are preferable.

Examples of Z ⁻ include an anion represented by the following formula (11-2-1) (an anion represented by R ^D1 —COO ^{— in} which R ^D1 is a phenyl group), and the following formula (11-2-2). in formula anion ^(R D1 -SO ₃ the ^{R D1} is 1,7,7-trimethyl bicyclo [2.2.1] heptan-2-one group derived from ^- anions represented by), the following formula An anion represented by (11-2-3) (an anion represented by R ^D1 —N ^— SO ₂ —R ^{D2 wherein} R ^D1 is a butyl group and R ^D2 is a trifluoromethyl group) is preferable. .

As the photodegradable acid diffusion controller,
As a sulfonium salt compound, for example,
Triphenylsulfonium hydroxide, triphenylsulfonium salicylate, triphenylsulfonium 4-trifluoromethyl salicylate, diphenyl-4-hydroxyphenylsulfonium salicylate, triphenylsulfonium 10-camphorsulfonate, 4-t-butoxy Examples thereof include phenyl diphenylsulfonium 10-camphorsulfonate.

Examples of the iodonium salt compound include:
Bis (4-t-butylphenyl) iodonium hydroxide, bis (4-t-butylphenyl) iodonium salicylate, bis (4-t-butylphenyl) iodonium 4-trifluoromethyl salicylate, bis (4- t-butylphenyl) iodonium 10-camphorsulfonate and the like.

[E] The acid diffusion controller can be used alone or in combination of two or more. [E] As the content of the acid diffusion controller, when the [E] acid diffusion controller is an [E] acid diffusion controller, the total amount of the polymer contained in the radiation-sensitive resin composition is 100 parts by mass. 10 parts by mass or less is preferable, and 5 parts by mass or less is more preferable.
[E] If the acid diffusion controller is contained excessively, the sensitivity of the resulting resist film may be lowered.

<[F] additive>
In addition to the above components, the radiation-sensitive resin composition contains an uneven distribution accelerator, a surfactant, an alicyclic skeleton-containing compound, a sensitizer, a crosslinking agent, and the like as an additive [F] as necessary. be able to.

(Uniformity promoting agent)
The uneven distribution accelerator has an effect of segregating the water-repellent additive contained in the radiation-sensitive resin composition on the resist coating surface more efficiently. By adding the uneven distribution accelerator to the radiation sensitive resin composition, the amount of the water repellent additive added can be reduced as compared with the conventional case. Therefore, it is possible to further suppress the elution of components from the resist film to the immersion liquid without damaging the basic resist characteristics such as LWR, development defects, and pattern collapse resistance, and to perform immersion exposure at a higher speed by high-speed scanning. As a result, it is possible to improve the hydrophobicity of the resist film surface that suppresses immersion-derived defects such as watermark defects. Examples of such an uneven distribution promoter include low molecular compounds having a relative dielectric constant of 30 or more and 200 or less and a boiling point at 1 atm of 100 ° C. or more. Examples of such compounds include lactone compounds, carbonate compounds, nitrile compounds, and polyhydric alcohols.

  Examples of the lactone compound include γ-butyrolactone, valerolactone, mevalonic lactone, norbornane lactone, and the like.

  Examples of the carbonate compound include propylene carbonate, ethylene carbonate, butylene carbonate, vinylene carbonate, and the like.

  Examples of the nitrile compound include succinonitrile. Examples of the polyhydric alcohol include glycerin and the like.

  Among these, lactone compounds and carbonate compounds are preferable, γ-butyrolactone and propylene carbonate are more preferable, and γ-butyrolactone is more preferable.

  The content of the uneven distribution accelerator in the radiation sensitive resin composition is usually 10 to 500 parts by mass with respect to 100 parts by mass of the total amount of the polymer contained in the radiation sensitive resin composition. Preferably it is 30-300 mass parts. As said uneven distribution promoter, only 1 type may be contained and 2 or more types may be contained.

(Surfactant)
A surfactant is a component that exhibits an effect of improving coatability, developability, and the like. Examples of the surfactant include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octylphenyl ether, polyoxyethylene n-nonylphenyl ether, polyethylene glycol dilaurate, polyethylene glycol In addition to nonionic surfactants such as distearate, commercially available products include KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, no. 95 (manufactured by Kyoeisha Chemical Co., Ltd.), F-top EF301, EF303, EF352 (manufactured by Tochem Products), MegaFuck F171, F173 (manufactured by Dainippon Ink & Chemicals), Florard FC430, FC431 (manufactured by Sumitomo 3M), Asahi Examples include Guard AG710, Surflon S-382, SC-101, SC-102, SC-103, SC-104, SC-105, SC-106 (manufactured by Asahi Glass). These surfactants can be used individually by 1 type or in mixture of 2 or more types. As content of surfactant, it is 2 mass parts or less normally with respect to 100 mass parts of total amounts of the polymer contained in the said radiation sensitive resin composition.

(Alicyclic skeleton-containing compound)
The alicyclic skeleton-containing compound is a component having an action of further improving dry etching resistance, pattern shape, adhesion to a substrate, and the like. Examples of the alicyclic skeleton-containing compound include:
Adamantane derivatives such as 1-adamantanecarboxylic acid, 2-adamantanone, 1-adamantanecarboxylate t-butyl;
Deoxycholic acid esters such as t-butyl deoxycholate, t-butoxycarbonylmethyl deoxycholic acid, 2-ethoxyethyl deoxycholic acid;
Lithocholic acid esters such as t-butyl lithocholic acid, t-butoxycarbonylmethyl lithocholic acid, 2-ethoxyethyl lithocholic acid;
3- [2-Hydroxy-2,2-bis (trifluoromethyl) ethyl] tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodecane, 2-hydroxy-9-methoxycarbonyl-5-oxo-4-oxa-tricyclo [4.2.1.0 ^3,7 ] nonane, and the like. These alicyclic skeleton-containing compounds can be used singly or in combination of two or more. The content of the alicyclic skeleton-containing compound is usually 50 parts by mass or less, preferably 30 parts by mass or less, with respect to 100 parts by mass of the total amount of the polymer contained in the radiation-sensitive resin composition. is there.

(Sensitizer)
The sensitizer absorbs energy other than the energy of radiation absorbed by the [C] acid generator, and transmits the energy to the [C] acid generator in the form of, for example, radicals, thereby It has the effect of increasing the production amount, and has the effect of improving the “apparent sensitivity” of the radiation-sensitive resin composition. Examples of the sensitizer include carbazoles, acetophenones, benzophenones, naphthalenes, phenols, biacetyl, eosin, rose bengal, pyrenes, anthracenes, phenothiazines, and the like. These sensitizers can be used individually by 1 type or in mixture of 2 or more types.

(Crosslinking agent)
In the case of using the radiation-sensitive resin composition as a negative radiation-sensitive resin composition, a polymer (hereinafter referred to as “crosslinking agent”) that can crosslink a polymer soluble in an alkali developer in the presence of an acid. ) May be blended. Examples of the crosslinking agent include compounds having one or more functional groups having crosslinking reactivity with a polymer soluble in an alkali developer (hereinafter also referred to as “crosslinkable functional groups”).

  Examples of the crosslinkable functional group include glycidyl ether group, glycidyl ester group, glycidyl amino group, methoxymethyl group, ethoxymethyl group, benzyloxymethyl group, acetoxymethyl group, benzoyloxymethyl group, formyl group, acetyl group, Examples thereof include a vinyl group, an isopropenyl group, a (dimethylamino) methyl group, a (diethylamino) methyl group, a (dimethylolamino) methyl group, a (diethylolamino) methyl group, and a morpholinomethyl group.

  Examples of the crosslinking agent include compounds described in paragraphs [0169] to [0172] of WO2009 / 51088.

  As the crosslinking agent, a methoxymethyl group-containing compound is particularly preferable, and among them, dimethoxymethylurea and tetramethoxymethylglycoluril are more preferable. In the negative radiation sensitive resin composition, the crosslinking agent can be used alone or in admixture of two or more.

  The content of the crosslinking agent is preferably 5 to 95 parts by mass, more preferably 15 to 85 parts by mass, and particularly preferably 20 to 75 parts by mass with respect to 100 parts by mass of the polymer soluble in the alkali developer. is there. If the content of the crosslinking agent is less than 5 parts by mass, the remaining film ratio tends to decrease, the pattern meanders or swells easily, and if it exceeds 95 parts by mass, the alkali developability tends to decrease. .

  [F] In addition to the above, dyes, pigments, adhesion aids and the like can also be used as additives. For example, by using a dye or a pigment, the latent image of the exposed portion can be visualized and the influence of halation during exposure can be reduced. Moreover, the adhesiveness with a board | substrate can be improved by mix | blending an adhesion aid. Examples of additives other than the above include alkali-soluble resins, low-molecular alkali solubility control agents having an acid-dissociable protecting group, antihalation agents, storage stabilizers, antifoaming agents, and the like. In addition, as for [F] additive, 1 type of various additives demonstrated above may be used independently, and 2 or more types may be used together.

<Preparation of radiation-sensitive resin composition>
The radiation-sensitive resin composition of the present invention is usually dissolved in the [B] solvent so that the total solid content concentration is 1 to 50% by mass, preferably 3 to 25% by mass in use, It is prepared by filtering with a filter having a pore size of about 0.02 μm.

  In addition, the said radiation sensitive resin composition is so preferable that there is little content of impurities, such as a halogen ion and a metal. When the content of such impurities is small, the sensitivity, resolution, process stability, pattern shape and the like of the resist film can be further improved. Therefore, the polymer such as the above-mentioned [A] polymer and [D] other polymer to be contained in the radiation-sensitive resin composition is, for example, a chemical purification method such as water washing, liquid-liquid extraction, or the like. It is preferable to purify by a combination of a physical purification method and a physical purification method such as ultrafiltration and centrifugation.

<Method for forming resist pattern>
The resist pattern forming method includes, for example, (1) a step of forming a resist film on the substrate using the radiation-sensitive resin composition (step (1)), (2) the formed resist film (necessary Accordingly (via an immersion medium), a step of exposing by exposure to radiation through a mask having a predetermined pattern (step (2)), a step of heating the exposed resist film (step (3)), and (4 ) A step of developing the heated resist film (step (4)). Hereinafter, each step will be described.

  In step (1), the radiation-sensitive resin composition is applied to a substrate (silicon wafer, silicon dioxide, wafer coated with an antireflection film, etc.) by an appropriate application means such as spin coating, cast coating, roll coating or the like. A resist film is formed by coating on the top. Specifically, after applying the radiation-sensitive resin composition so that the resulting resist film has a predetermined film thickness, the solvent in the film is vaporized by soft baking (SB). Form.

  In the step (2), the resist film formed in the step (1) is irradiated with radiation (possibly through an immersion medium such as water) to be exposed. In this case, radiation is irradiated through a mask having a predetermined pattern. As the radiation, irradiation is performed by appropriately selecting from visible light, ultraviolet light, far ultraviolet light, X-rays, charged particle beams and the like according to the line width of the target pattern. Among these, far ultraviolet rays represented by ArF excimer laser light (wavelength 193 nm) and KrF excimer laser light (wavelength 248 nm) are preferable, and ArF excimer laser light is particularly preferable.

  Step (3) is a PEB (post-exposure bake) step. In the exposed portion of the resist film in step (2), the [A] polymer is generated by the action of an acid generated from the [C] acid generator. This is a step of deprotecting an acid dissociable group such as. There is a difference in the solubility of the exposed portion (exposed portion) and the unexposed portion (unexposed portion) in the alkaline developer. Conventionally, PEB is appropriately selected within the range of 90 ° C. to 180 ° C., but according to the radiation-sensitive resin composition of the present invention, the PEB temperature can be lowered to 90 ° C. or lower.

  In step (4), the resist film exposed in step (3) is developed with a developer to form a predetermined resist pattern. After development, it is common to wash with water and dry. Examples of the developer include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine. , Ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide, pyrrole, piperidine, choline, 1,8-diazabicyclo- [5.4.0] -7-undecene, 1,5-diazabicyclo- [4.3. 0] An aqueous alkaline solution in which at least one of alkaline compounds such as 5-nonene is dissolved is preferable.

  Moreover, when performing immersion exposure, it is preferable that the said radiation sensitive resin composition contains a water-repellent additive. However, in the case where the radiation-sensitive resin composition does not contain a water repellent additive, before the step (2), in order to protect the direct contact between the immersion liquid and the resist film, the immersion liquid is insoluble. The immersion protective film can be provided on the resist film. As the protective film for immersion, a solvent peeling type protective film (see JP-A-2006-227632) that peels off with a solvent before the step (4), and a developer peeling type that peels off simultaneously with the development in the step (4). Any of the protective films (see International Publication No. 2005/69076, International Publication No. 2006/35790) may be used. However, from the viewpoint of throughput, it is preferable to use a developer peelable protective film.

<Polymer>
The polymer of the present invention has the structural unit (I) represented by the above formula (1). The polymer has a double bond adjacent cyclic hydrocarbon group as an acid dissociable group, which is very easy to dissociate. Therefore, according to the said polymer, it becomes possible to make PEB temperature in the case of resist pattern formation lower than the conventional temperature. Therefore, the said polymer is suitable as components, such as a radiation sensitive resin composition used for a lithography technique, for example. In addition, since detailed description of the said polymer is performed in the term of the description of [A] polymer contained in the said radiation sensitive resin composition, it abbreviate | omits here.

<Compound>
The compound of the present invention is represented by the above formula (i). Since the compound has a structure represented by the above formula (i), it can be suitably used as a monomer compound in which the structural unit (I) is incorporated into the polymer. In addition, since detailed description of the said compound is performed in the term of description of [A] polymer contained in a radiation sensitive resin composition, it abbreviate | omits here.

  By using the radiation sensitive resin composition of the present invention, the PEB temperature at the time of pattern formation can be lowered, and even in that case, the pattern shape is good and the LWR is small without requiring an increase in the exposure amount. A resist pattern in which the occurrence of scum and bridge defects is suppressed can be obtained. Therefore, the radiation-sensitive resin composition is suitable for fine processing using a lithography technique.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples. The measuring method of various physical property values is shown below.

[ ¹ H-NMR analysis, ¹³ C-NMR analysis]
¹ H-NMR analysis and ¹³ C-NMR analysis were performed using a nuclear magnetic resonance apparatus (“JNM-ECX400” manufactured by JEOL Ltd.).

<Synthesis of Compound (i)>
[Example 1]
Synthesis of 1-vinyl-1-cyclooctyl methacrylate A 1 L reactor equipped with a stirrer and a dropping funnel was charged with 12.6 g (100 mmol) of cyclooctanone and 200 mL of tetrahydrofuran (THF). After dropwise addition of 120 mL (120 mmol) of 1M THF solution of vinylmagnesium chloride, the mixture was reacted at 20 ° C. for 16 hours with stirring. After the reaction, while cooling the inside of the reactor to 0 ° C., a mixture of 12.1 g (120 mmol) of triethylamine and 12.5 g (120 mmol) of methacryloyl chloride was dropped from the dropping funnel, and then stirred at 20 ° C. for 2 hours. Reacted. The obtained suspension was filtered under reduced pressure, the filtrate was concentrated under reduced pressure, and the resulting residue was purified by silica gel column chromatography (eluent: petroleum ether / diethyl ether = 20/1 (mass ratio)). 14.5 g of a colorless oil of 1-vinyl-1-cyclooctyl methacrylate represented by the following formula (M-17) was obtained (yield: 65%).

¹ H-NMR (CDCl ₃ ) δ: 1.38-1.71 (m, ¹⁰ H, CH ₂ ), 1.80-2.00 (m, 5 H), 2.23 (dd, 2 H, CH ₂ ) _{, 5.10-5.24 (m, 2H, CH} 2), 5.42-5.57 (m, 1H, CH 2), 5.98-6.15 (m, 2H, CH)
¹³ C-NMR (CDCl ₃ ) δ: 18.3 (CH ₃ ), 21.4, 24.7, 28.0, 32.4 (CH ₂ ), 86.0 (C), 113.4, 129 .5 (CH ₂ ), 129.9, 141.9 (CH), 164.8 (CO)

[Example 2]
Synthesis of 1-vinyl-1-cyclopentyl methacrylate In Example 1, in place of 12.6 g of cyclooctanone, 8.4 g (100 mmol) of cyclopentanone was used. 6.8 g of colorless oil of 1-vinyl-1-cyclopentyl methacrylate represented by (M-15) was obtained (yield 71%).

¹ H-NMR (CDCl ₃ ) δ: 1.57-1.86 (m, 4H, CH ₂ ), 1.87-2.08 (m, 5H), 2.12-2.31 (m, 2H _{, CH 2), 5.08-5.24 (m} , 2H, CH 2), 5.44-5.59 (m, 1H, CH 2), 5.98-6.09 (m, 1H, CH ), 6.19 (dd, 1H, CH ₂ )
¹³ C-NMR (CDCl ₃ ) δ: 18.5 (CH ₃ ), 23.2, 37.6 (CH ₂ ), 90.7 (C), 113.1 (CH ₂ ), 129.6 (CH ), 129.9 (CH ₂ ), 140.1 (CH), 165.2 (CO)

[Example 3]
Synthesis of 1-vinyl-1-cyclohexyl methacrylate In Example 1, the following formula was used, except that 9.8 g (100 mmol) of cyclohexanone was used instead of 12.6 g of cyclooctanone. A colorless oil 7.8 g of 1-vinyl-1-cyclohexyl methacrylate represented by (M-16) was obtained (yield 62%).

¹ H-NMR (CDCl ₃ ) δ: 1.25-1.30 (m, 1H, CH ₂ ), 1.49-1.62 (m, 7H, CH ₂ ), 1.80-1.94 ( _{m, 3H), 2.21-2.24 (m} , 2H, CH 2), 5.10-5.20 (m, 2H, CH 2), 5.75 (dd, 1H, CH 2), 6 .04 (m, 1H, CH) , 6.34 (dd, 1H, CH 2)
¹³ C-NMR (CDCl ₃ ) δ: 18.4 (CH ₃ ), 21.8, 25.3, 34.8 (CH ₂ ), 82.0 (C), 113.6, 129.7 (CH ₂ ), 129.8 (CH ₂ ), 141.7 (CH), 164.8 (CO)

[Example 4]
Synthesis of 2-vinyl-2-adamantyl methacrylate In Example 1, in place of 12.6 g of cyclooctanone, 15.0 g (100 mmol) of 2-adamantanone was used. A colorless oil of 9.3 g of 2-vinyl-2-adamantyl methacrylate represented by the formula (M-18) was obtained (yield 53%).

¹ H-NMR (CDCl ₃ ) δ: 1.66-2.16 (m, 14H, CH, CH ₂ ), 1.80-1.94 (m, 3H), 5.27 (dd, 1H, CH _{2), 5.33 (dd, 1H} , CH 2), 5.75 (dd, 1H, CH 2), 6.08 (dd, 1H, CH 2), 6.35 (m, 1H, CH 2)
¹³ C-NMR (CDCl ₃ ) δ: 18.1 (CH ₃ ), 26.8, 27.2 (CH), 32.9, 34.3 (CH ₂ ), 35.1 (CH), 85. 3 (C), 115.7, 129.6 (CH ₂ ), 130.0, 140.6 (CH), 164.5 (CO)

<Synthesis of [A] polymer and [D] other polymer>
Using the synthesized compound (i) and the following compounds (M-1) to (M-14), [A] polymer and [D] other polymer were synthesized.

[Example 5]
(Synthesis of polymer (A-1))
To a 200 mL reactor equipped with a stirrer, 10 g of 2-butanone was charged, 2.20 g (10 mmol) of compound (M-17), 0.59 g (2.5 mmol) of compound (M-5), compound (M-7) 2 20 g (10 mmol) and compound (M-11) 0.33 g (2.5 mmol), and 0.25 g of dimethyl 2,2′-azobis (2-methylpropionate) as a polymerization initiator were added and dissolved. After purging with nitrogen for 30 minutes, the mixture was heated to 80 ° C. with stirring. The polymerization reaction was carried out for 6 hours with the start of heating as the start of polymerization. After completion of the polymerization reaction, the polymerization solution was cooled with water and cooled to 30 ° C. or lower, and then concentrated under reduced pressure with an evaporator until the mass of the polymerization solution became 7.5 g. The obtained concentrated liquid was put into a methanol / water (50 g / 50 g) mixed liquid to precipitate a slime-like white solid. The liquid part was removed by decantation, and the mixture was again poured into a methanol / water (50 g / 50 g) mixed solution, and this slime-like white solid was repeatedly washed twice. The obtained solid was vacuum-dried at 60 ° C. for 15 hours to obtain 3.51 g of a white powder of the polymer (A-1) (yield 66%). Mw of the polymer (A-1) was 5,500, and Mw / Mn was 1.41. As a result of ¹³ C-NMR analysis, compound (M-17) giving structural unit (I), compound (M-5) giving structural unit (V), compound (M-7) giving structural unit (VII) ) And other structural unit-derived structural units derived from the compound (M-11) were 40.2 mol%, 8.3 mol%, 40.7 mol% and 10.8 mol%, respectively. .

[Examples 6 to 21]
(Synthesis of polymers (A-2) to (A-17))
The total amount of monomers used was 25 mmol, and the same manner as in Example 5 except that the types and amounts of monomers used (molar ratio) were as shown in Table 1 or Table 2. [A] A polymer was synthesized. “-” In Table 1 and Table 2 indicates that no monomer was used as the corresponding structural unit. The physical properties of the obtained polymer are also shown in Tables 1 and 2. About a polymer (A-8)-(A-17), the value of fluorine atom content rate (mass%) is also shown.

[Synthesis Examples 1 to 4]
(Synthesis of polymers (D-1) to (D-4))
Each [D] polymer was synthesize | combined like Example 5 except having used the monomer of the kind and usage-amount shown in Table 1 or Table 2. FIG. The physical properties of the obtained polymer are also shown in Tables 1 and 2.

  In addition, in the polymers (A-1) to (A-17) which are the [A] polymers synthesized as described above, the aliphatic cyclic carbonization possessed by the compound (i) which gives the structural unit (I) It was found that the vinyl group adjacent to the hydrogen group remained with little reaction in the polymerization reaction.

<Preparation of radiation-sensitive resin composition>
[B] solvent, [C] acid generator, [E] acid diffusion control agent, and [F] additive which comprise a radiation sensitive resin composition are shown below.

[B] Solvent B-1: Propylene glycol monomethyl ether acetate B-2: Cyclohexanone

[C] Acid generator The structural formula is shown below.
C-1: Triphenylsulfonium nonafluoro-n-butanesulfonate

[E] Acid diffusion controller The structural formula is shown below.
E-1: N- (t-butoxycarbonyl) -4-hydroxypiperidine

[F] Additive (Uneven distribution promoter)
(F-1): γ-butyrolactone

[Example 22]
[A] 100 parts by mass of polymer (A-1) as polymer and 5 parts by mass of polymer (A-8), [B] 1,500 parts by mass as solvent (B-2) ) 650 parts by weight, [C] 9.9 parts by weight as an acid generator, [E] 1.5 parts by weight as an acid diffusion controller, and [F] additive As a mixture, 100 parts by mass of γ-butyrolactone was mixed to prepare a radiation sensitive resin composition.

(Examples 23 to 48, Comparative Examples 1 to 4)
[A] Each radiation-sensitive material in the same manner as in Example 22 except that each component of the types and blending amounts shown in Table 3 was used as the polymer, [D] other polymer, and [C] acid generator. A functional resin composition was prepared.

<Evaluation>
[Pattern formability]
Resist film with a film thickness of 110 nm using a radiation sensitive resin composition prepared above on a 12-inch silicon wafer on which a lower antireflection film is formed using an antireflection coating material for semiconductor (ARC66, manufactured by Nissan Chemical Co., Ltd.) And SB was performed at 120 ° C. for 60 seconds. Next, this resist film was subjected to a line and line process using an ArF excimer laser immersion exposure apparatus (NSR S610C, manufactured by NIKON) with a target size of 45 nm under the conditions of NA = 1.3, ratio = 0.800, Dipole. It exposed through the mask pattern of space (1L1S). After the exposure, PEB was performed at 80 ° C. for 60 seconds. Thereafter, using a 2.38% by mass tetramethylammonium hydroxide aqueous solution as a developer, the developing device (LITIUS Pro-i, manufactured by Tokyo Electron Co., Ltd.) was used for developing with a GP nozzle for 10 seconds, followed by washing with water for 15 seconds. It was dried to form a positive resist pattern. At this time, the exposure amount for forming a line and space having a width of 45 nm was determined as the optimum exposure amount. The cross-sectional shape of the pattern formed with this optimum exposure dose was observed with a scanning electron microscope (S-4800, manufactured by Hitachi High-Technologies), and as shown in FIG. 1, the pattern 2 formed on the substrate 1 was observed. When the upper line width is L1 and the lower line width is L2, the case where (L1-L2) / L1 falls within the range of -0.15 to +0.15 is "A", (L1-L2) / L1 When “B” was smaller than −0.15 or larger than +0.15, “B” was evaluated.

[LWR performance]
A positive resist pattern was formed in the same manner as in the evaluation of the pattern formability. The pattern resolved at the optimum exposure amount using the scanning electron microscope is observed from above, and the line width is measured at 10 points at arbitrary points. The 3σ (variation) of the measured value is expressed as LWR ( Unit: nm). The case where the LWR value was 5.0 nm or less was evaluated as “A”, and the case where the LWR value exceeded 5.0 nm was evaluated as “B”.

[Scum suppression]
In the observation with the scanning electron microscope in the evaluation of the pattern forming property, when no undissolved portion is observed in the exposed portion, “Scum Suppression” is “A”, and when undissolved portion is recognized, “B” "

[Bridge defect suppression]
A line and space pattern was formed in the same procedure as the evaluation of the pattern forming property except that a line and space pattern (1L1S) having a line width of 100 nm was used as a mask. At this time, the exposure amount for forming a line and space having a width of 100 nm was determined as the optimum exposure amount. In this case, a scanning electron microscope (“S-9380”, manufactured by Hitachi High-Technologies Corporation) was used for length measurement. The defect performance on the formed line and space pattern (1L1S) having a line width of 100 nm was measured using a defect inspection apparatus (“KLA2810”, manufactured by KLA-Tencor). The defect measured by the defect inspection apparatus “KLA2810” was observed using the scanning electron microscope “S-9380”, and the number of bridge defects was measured to evaluate the bridge defect prevention performance. The bridge defect prevention performance was evaluated as “A” when the number of detected bridge defects is less than 50, “B” when the number is 50 or more and less than 100, and “C” when the number exceeds 100. . The evaluation results are shown in Table 3.

From the results of Table 3, the resist film formed using the radiation-sensitive resin compositions of Examples 22 to 48 containing the [A] polymer according to the present invention, the [A] polymer is the base polymer only. In both cases of the water repellent additive alone and both the base polymer and the water repellent additive, the pattern formability and the LWR performance are good, and the occurrence of scum and bridge defects can be suppressed. Indicated. It has also been shown that these properties are higher, especially when both the base polymer and the water repellent additive are [A] polymers. On the other hand, the radiation sensitive resin compositions of Comparative Examples 1 to 4 in which both the base polymer and the water repellent additive are not the [A] polymer are those resists compared to the radiation sensitive resin compositions of the examples. All the pattern characteristics were inferior.
In addition, the optimal exposure amount in the case of the said pattern formation evaluation was 30 J / m < ² >. On the other hand, in Comparative Example 1, the optimum exposure amount when the PEB temperature was changed to 80 ° C. and 100 ° C. as in the conventional case was 32 J / m ² . From this, in the radiation sensitive resin composition of an Example, it can be said that it is possible to make PEB temperature low, without requiring the amount of exposure to be raised compared with the past.

  ADVANTAGE OF THE INVENTION According to this invention, the radiation sensitive resin composition excellent in pattern formation property, LWR performance, scum suppression property, and bridge defect suppression property can be provided, aiming at low temperature of PEB temperature. Therefore, the radiation sensitive resin composition can be suitably used as a chemically amplified resist for manufacturing semiconductor devices.

1 Substrate 2 Pattern L1 Line width at the top of the pattern L2 Line width at the bottom of the pattern

Claims (8)

[A] A radiation-sensitive resin composition containing a polymer having a structural unit (I) represented by the following formula (1), and [B] a solvent.

(In Formula (1), R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R ^C is a group that forms a divalent aliphatic cyclic hydrocarbon group together with R ^a . Some or all of the hydrogen atoms of the aliphatic cyclic hydrocarbon group may be substituted, R ^a is a carbon atom, and R ^{1 to} R ³ are each independently a hydrogen atom or a carbon number of 1 To a monovalent chain saturated hydrocarbon group having from 10 to 10 or a monovalent aliphatic cyclic saturated hydrocarbon group having from 3 to 20 carbon atoms, hydrogen contained in the chain saturated hydrocarbon group and the aliphatic cyclic saturated hydrocarbon group. (Part or all of the atoms may be substituted, provided that any of R ^{1 to} R ³ may be bonded to each other to form a cyclic structure.) The radiation sensitive resin composition according to claim 1, wherein the structural unit (I) is a structural unit (I-1) represented by the following formula (1-1).

(In the formula (1-1), R and R ^{1 to} R ³ have the same meanings as the formula (1). N _C is an integer of 1 to 4. R ^S represents —RP ¹ , —R. ^{P2 -O-R P1, -R P2} -CO-R P1, -R P2 -CO-oR P1, -R P2 -O-CO-R P1, -R P2 -OH, -R P2 -CN or -R a ^P2 -COOH ^{.R P1} represents a monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms, 1 monovalent aliphatic cyclic saturated hydrocarbon group or a C6-30 having 3 to 20 carbon atoms R ^P2 represents a single bond, a divalent chain saturated hydrocarbon group having 1 to 10 carbon atoms, a divalent aliphatic cyclic saturated hydrocarbon group having 3 to 20 carbon atoms, or R ^P2 is a divalent aromatic hydrocarbon group having 6 to 30 carbon atoms. However, a chain saturated hydrocarbon group in R ^P1 and R ^P2, alicyclic saturated hydrocarbon Good .n _S be some or all substituted by a fluorine atom of the hydrogen atoms included in the group and the aromatic hydrocarbon group is an integer of 0 to 3. However, if n _S is 2 or more, plural R ^S may be the same or different.) The radiation sensitive resin composition according to claim 1, wherein the structural unit (I) is a structural unit (I-2) represented by the following formula (1-2).

(In the formula (1-2), R and ^R 1 to R ³ is as defined in the above formula (1) .R ^{S is, -R P1, -R P2 -O-} R P1, -R P2 -CO ^{-R P1, -R P2 -CO-oR} P1, -R P2 -O-CO-R P1, a ^-R P2 ^-OH, -R P2 -CN or ^-R P2 -COOH ^{.R P1} has a carbon number 1-10 monovalent chain saturated hydrocarbon group, a monovalent aliphatic cyclic saturated hydrocarbon group or a monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms having 3 to 20 carbon atoms .R ^P2 Is a single bond, a divalent chain saturated hydrocarbon group having 1 to 10 carbon atoms, a divalent aliphatic cyclic saturated hydrocarbon group having 3 to 20 carbon atoms, or a divalent aromatic carbon group having 6 to 30 carbon atoms. is a hydrogen group. However, organic chain saturated hydrocarbon group, aliphatic cyclic saturated hydrocarbon group and the aromatic hydrocarbon group for R ^P1 and R ^P2 That good .n _S be some or all substituted by a fluorine atom of the hydrogen atoms is an integer of 0 to 3. However, if n _S is 2 or more, plural structured R ^S are identical or different May be.)   The radiation sensitive resin composition according to claim 1, wherein the polymer [A] is a polymer having a fluorine atom.   The radiation sensitive resin composition according to claim 1, wherein the polymer [A] is a polymer further having a structural unit (VII) containing a lactone structure.   [C] The radiation sensitive resin composition according to any one of claims 1 to 5, further comprising a radiation sensitive acid generator. The polymer which has structural unit (I) represented by following formula (1).

(In Formula (1), R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R ^C is a group that forms a divalent aliphatic cyclic hydrocarbon group together with R ^a . Some or all of the hydrogen atoms of the aliphatic cyclic hydrocarbon group may be substituted, R ^a is a carbon atom, and R ^{1 to} R ³ are each independently a hydrogen atom or a carbon number of 1 To a monovalent chain saturated hydrocarbon group having from 10 to 10 or a monovalent aliphatic cyclic saturated hydrocarbon group having from 3 to 20 carbon atoms, hydrogen contained in the chain saturated hydrocarbon group and the aliphatic cyclic saturated hydrocarbon group. (Part or all of the atoms may be substituted, provided that any of R ^{1 to} R ³ may be bonded to each other to form a cyclic structure.) A compound represented by the following formula (i).

(In formula (i), R is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ^C is a group which forms a divalent aliphatic cyclic hydrocarbon group together with R ^a . Some or all of the hydrogen atoms of the aliphatic cyclic hydrocarbon group may be substituted, R ^a is a carbon atom, and R ^{1 to} R ³ are each independently a hydrogen atom or a carbon number of 1 To a monovalent chain saturated hydrocarbon group having from 10 to 10 or a monovalent aliphatic cyclic saturated hydrocarbon group having from 3 to 20 carbon atoms, hydrogen contained in the chain saturated hydrocarbon group and the aliphatic cyclic saturated hydrocarbon group. (Part or all of the atoms may be substituted, provided that any of R ^{1 to} R ³ may be bonded to each other to form a cyclic structure.)

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