JP2007327983A - Radiation-sensitive resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiation-sensitive resin composition which gives a good pattern profile, excels in focal depth, and is used for liquid immersion lithography by which irradiation with a radiation is carried out through a liquid for liquid immersion lithography having a higher refractive index than air at a wavelength of 193 nm, and in which materials elute in a small amount into the liquid for liquid immersion lithography such as water with which the composition contacts in liquid immersion lithography. <P>SOLUTION: The radiation-sensitive resin composition is used for a resist pattern forming method including liquid immersion lithography by which irradiation with a radiation is carried out through a liquid for liquid immersion lithography between a lens and a photoresist film, and contains a resin (A) and at least one radiation-sensitive acid generator (B) represented by formulae (1) and (2), wherein R<SP>1</SP>is H; R<SP>2</SP>is alkoxyl; X is butylene; and each R<SP>4</SP>and R<SP>5</SP>are fluoroalkyl. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a radiation-sensitive resin composition, and in particular, a resist pattern including immersion exposure in which radiation is irradiated between a lens and a photoresist film through an immersion exposure liquid having a refractive index higher than that of air at a wavelength of 193 nm. The present invention relates to a radiation sensitive resin composition applied to the above.

In the field of microfabrication represented by the manufacture of integrated circuit elements, in order to obtain a higher degree of integration, recently, a lithography technique capable of microfabrication at a level of 100 nm or less is required.
In conventional lithography processes, near ultraviolet rays such as i-rays are generally used as radiation, and it is said that fine processing at the subquarter micron level is extremely difficult with this near ultraviolet rays. Therefore, in order to enable microfabrication at a level of 200 nm or less, use of radiation having a shorter wavelength is being studied. Examples of such short-wavelength radiation include an emission line spectrum of a mercury lamp, far ultraviolet rays typified by an excimer laser, an X-ray, an electron beam, and the like. Among these, a KrF excimer laser (wavelength 248 nm) is particularly preferable. ) Or ArF excimer laser (wavelength 193 nm) has been attracting attention.
As a resist suitable for such excimer laser irradiation, a component having an acid-dissociable functional group and a component that generates an acid upon irradiation with radiation (hereinafter also referred to as “exposure”) (hereinafter referred to as “acid generator”). Many resists that utilize the chemical amplification effect (hereinafter referred to as “chemically amplified resist”) have been proposed. As the chemically amplified resist, for example, a resist containing a resin having a t-butyl ester group of carboxylic acid or a t-butyl carbonate group of phenol and an acid generator has been proposed. In this resist, the t-butyl ester group or t-butyl carbonate group present in the resin is dissociated by the action of an acid generated by exposure, and the resin has an acidic group composed of a carboxyl group or a phenolic hydroxyl group. As a result, the phenomenon that the exposed region of the resist film becomes readily soluble in an alkali developer is utilized.

  In such a lithography process, further fine pattern formation (for example, a fine resist pattern having a line width of about 90 nm) will be required in the future. In order to achieve such a pattern formation finer than 90 nm, it is conceivable to shorten the light source wavelength of the exposure apparatus and increase the numerical aperture (NA) of the lens as described above. However, a new expensive exposure apparatus is required to shorten the light source wavelength. Further, when the lens has a high NA, the resolution and the depth of focus are in a trade-off relationship. Therefore, there is a problem that the depth of focus decreases even if the resolution is increased.

  Recently, an immersion exposure (liquid immersion lithography) method has been developed as a lithography technique capable of solving such problems. In this method, a liquid refractive index medium (immersion liquid) such as pure water or a fluorine-based inert liquid having a predetermined thickness is interposed at least on the resist film between the lens and the resist film on the substrate during exposure. It is. In this method, a light source having the same exposure wavelength can be used by replacing the exposure optical path space, which has conventionally been an inert gas such as air or nitrogen, with a liquid having a higher refractive index (n), such as pure water. Similar to the case of using a light source with a shorter wavelength or the case of using a high NA lens, high resolution is achieved and there is no reduction in the depth of focus. Using such immersion exposure, it is possible to realize the formation of a resist pattern with low cost, high resolution, and excellent depth of focus using lenses mounted on existing equipment. Has been.

However, in this immersion exposure process, since the resist film comes into direct contact with a high refractive index liquid (immersion liquid) such as water at the time of exposure, there is a possibility that the acid generator and the like are eluted from the resist film. When the amount of the eluted material is large, there are problems that the lens is damaged, a predetermined pattern shape cannot be obtained, and sufficient resolution cannot be obtained.
Therefore, as a resist resin used in the immersion exposure apparatus, for example, resins described in Patent Document 1 and Patent Document 2 have been proposed.
However, even with resists using these resins, the depth of focus is not always sufficient.
In addition, in resists used in immersion exposure apparatuses, it has been eagerly desired to further reduce the amount of dissolved substances in water such as acid generators.

International Publication WO 2004/062422 JP 2005-173474 A

  An object of the present invention is to provide water in contact during immersion exposure, wherein the obtained pattern shape is good, the depth of focus is excellent, and the radiation exposure is performed through an immersion exposure liquid having a refractive index at a wavelength of 193 nm higher than that of air. An object of the present invention is to provide a radiation-sensitive resin composition used for immersion exposure with a small amount of eluate in the immersion exposure liquid.

式（１）および式（２）において、Ｒ¹は水素原子、フッ素原子、水酸基、炭素数１〜１０の直鎖状もしくは分岐状のアルキル基、炭素数１〜１０の直鎖状もしくは分岐状のアルコキシル基、または、炭素数２〜１１の直鎖状もしくは分岐状のアルコキシカルボニル基を表し、Ｒ²は炭素数１〜１０の直鎖状もしくは分岐状のアルキル基、炭素数１〜１０の直鎖状もしくは分岐状のアルコキシル基、または炭素数１〜１０の直鎖状、分岐状、もしくは環状のアルカンスルホニル基を表し、Ｘは炭素数２〜１０の２価の基を表し、各Ｒ⁴およびＲ⁵は、それぞれ相互に独立に炭素数１〜８の直鎖状、分岐状もしくは環状のフッ素化アルキル基、互いのＲ⁴が結合した炭素数２〜８のフッ素化アルキレン基を表し、または２個のＲ⁵が結合した炭素数２〜８のフッ素化アルキレン基を表し、ｎは０〜２の整数であり、ｍは０〜１０の整数である。 The radiation-sensitive resin composition of the present invention is used in a resist pattern forming method including immersion exposure in which radiation is irradiated between a lens and a photoresist film via an immersion exposure liquid. A radiation-sensitive resin composition comprising a radiation acid generator (B) and forming a photoresist film,
The radiation sensitive acid generator (B) is at least one radiation sensitive acid generator represented by the following formulas (1) and (2).

In Formula (1) and Formula (2), R ¹ is a hydrogen atom, a fluorine atom, a hydroxyl group, a linear or branched alkyl group having 1 to 10 carbon atoms, or a linear or branched group having 1 to 10 carbon atoms. Or an alkoxyl group having 2 to 11 carbon atoms or a linear or branched alkoxycarbonyl group having 2 to 11 carbon atoms, R ² is a linear or branched alkyl group having 1 to 10 carbon atoms, or 1 to 10 carbon atoms. Represents a linear or branched alkoxyl group or a linear, branched or cyclic alkanesulfonyl group having 1 to 10 carbon atoms, X represents a divalent group having 2 to 10 carbon atoms, and each R ⁴ and R ⁵ each independently represent a linear, branched or cyclic fluorinated alkyl group having 1 to 8 carbon atoms, or a fluorinated alkylene group having 2 to 8 carbon atoms to which R ⁴ is bonded. or the number of carbon atoms in which two R ⁵ are bonded Represents 8 fluorinated alkylene group, n is an integer of 0 to 2, m is an integer of 0.

式（３）および式（４）において、Ｒ¹およびＲ²は、式（１）および式（２）におけるそれらと同一であり、Ｒ³は独立に炭素数１〜１０の直鎖状もしくは分岐状のアルキル基、置換されていてもよいフェニル基もしくはナフチル基を表し、Ｒ^4'は、相互に独立に炭素数１〜８の直鎖状、分岐状もしくは環状のフッ素化アルキル基を表し、Ｒ^5'は、相互に独立に炭素数１〜８の直鎖状、分岐状もしくは環状のフッ素化アルキル基、または互いのＲ^5'が結合した炭素数２〜８のフッ素化アルキレン基を表し、ｎは０〜２の整数であり、ｍは０〜１０の整数である。 Another radiation sensitive acid generator (B) is at least one radiation sensitive acid generator represented by the following formulas (3) and (4).

In Formula (3) and Formula (4), R ¹ and R ² are the same as those in Formula (1) and Formula (2), and R ³ is independently a linear or branched group having 1 to 10 carbon atoms. And represents an optionally substituted phenyl group or naphthyl group, and R ^{4 ′} represents a linear, branched or cyclic fluorinated alkyl group having 1 to 8 carbon atoms, R ^{5 ′} represents, independently of each other, a linear, branched or cyclic fluorinated alkyl group having 1 to 8 carbon atoms, or a fluorinated alkylene group having 2 to 8 carbon atoms to which R ^{5 ′} is bonded. , N is an integer from 0 to 2, and m is an integer from 0 to 10.

  The radiation-sensitive resin composition of the present invention uses a radiation-sensitive acid generator represented by the formulas (1) to (4) excellent in water repellency for an acid-labile resin. It is possible to reduce the amount of eluate in contact with water. Therefore, it can be used very suitably for manufacturing semiconductor devices that will be further miniaturized in the future.

Radiation sensitive acid generator (B)
The acid generator that can be used in the present invention generates an acid upon exposure. The acid generator dissociates the acid dissociable group in the repeating unit present in the copolymer by the action of the acid generated by exposure. That is, the protecting group of the acid dissociable group is removed. As a result, the exposed portion of the resist film becomes readily soluble in an alkali developer, and has a function of forming a positive resist pattern. The acid generator in the present invention is preferably at least one selected from compounds represented by formulas (1) to (4).

式（１）〜式（４）において、Ｒ¹は水素原子、フッ素原子、水酸基、炭素数１〜１０の直鎖状もしくは分岐状のアルキル基、炭素数１〜１０の直鎖状もしくは分岐状のアルコキシル基、または、炭素数２〜１１の直鎖状もしくは分岐状のアルコキシカルボニル基を表し、Ｒ²は炭素数１〜１０の直鎖状もしくは分岐状のアルキル基、炭素数１〜１０の直鎖状もしくは分岐状のアルコキシル基、または炭素数１〜１０の直鎖状、分岐状、もしくは環状のアルカンスルホニル基を表し、ｎは０〜２の整数であり、ｍは０〜１０の整数である。
また、式（１）および式（２）において、Ｘは炭素数２〜１０の２価の基を表し、各Ｒ⁴およびＲ⁵は、それぞれ相互に独立に炭素数１〜８の直鎖状、分岐状もしくは環状のフッ素化アルキル基、互いのＲ⁴が結合したアルキレン基を表し、または２個のＲ⁵が結合したアルキレン基を表す。
式（３）および式（４）において、Ｒ³は独立に炭素数１〜１０の直鎖状もしくは分岐状のアルキル基、置換されていてもよいフェニル基もしくはナフチル基を表し、Ｒ^4'は、相互に独立に炭素数１〜８の直鎖状もしくは分岐状のフッ素化アルキル基を表し、Ｒ^5'は、相互に独立に炭素数１〜８の直鎖状もしくは分岐状のフッ素化アルキル基、または互いのＲ^5'が結合したアルキレン基を表す。

In the formulas (1) to (4), R ¹ is a hydrogen atom, a fluorine atom, a hydroxyl group, a linear or branched alkyl group having 1 to 10 carbon atoms, or a linear or branched group having 1 to 10 carbon atoms. Or an alkoxyl group having 2 to 11 carbon atoms or a linear or branched alkoxycarbonyl group having 2 to 11 carbon atoms, R ² is a linear or branched alkyl group having 1 to 10 carbon atoms, or 1 to 10 carbon atoms. Represents a linear or branched alkoxyl group or a linear, branched or cyclic alkanesulfonyl group having 1 to 10 carbon atoms, n is an integer of 0 to 2, and m is an integer of 0 to 10 It is.
In the formulas (1) and (2), X represents a divalent group having 2 to 10 carbon atoms, and each R ⁴ and R ⁵ are each independently a straight chain having 1 to 8 carbon atoms. Represents a branched or cyclic fluorinated alkyl group, an alkylene group in which each R ⁴ is bonded, or an alkylene group in which two R ⁵ are bonded.
In the formulas (3) and (4), R ³ independently represents a linear or branched alkyl group having 1 to 10 carbon atoms, an optionally substituted phenyl group or naphthyl group, and R ^{4 ′} represents Represents a linear or branched fluorinated alkyl group having 1 to 8 carbon atoms independently of each other, and R ^{5 ′} represents a linear or branched fluorinated alkyl group having 1 to 8 carbon atoms independently of each other. Or an alkylene group to which R ^{5 ′} is bonded to each other.

Examples of the linear or branched alkyl group having 1 to 10 carbon atoms in R ¹ , R ² , or R ³ include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, and an n-butyl group. 2-methylpropyl group, 1-methylpropyl group, t-butyl group, n-pentyl group, neopentyl group, n-hexyl group, n-heptyl group, n-octyl group, 2-ethylhexyl group, n-nonyl group , N-decyl group and the like. Of these alkyl groups, a methyl group, an ethyl group, an n-butyl group, and a t-butyl group are preferable.

Examples of the linear or branched alkoxyl group having 1 to 10 carbon atoms in R ¹ or R ² include methoxy group, ethoxy group, n-propoxy group, i-propoxy group, n-butoxy group, 2-methyl Propoxy group, 1-methylpropoxy group, t-butoxy group, n-pentyloxy group, neopentyloxy group, n-hexyloxy group, n-heptyloxy group, n-octyloxy group, 2-ethylhexyloxy group, n -Nonyloxy group, n-decyloxy group, etc. can be mentioned. Of these alkoxyl groups, a methoxy group, an ethoxy group, an n-propoxy group, and an n-butoxy group are preferable.

Examples of the linear or branched alkoxycarbonyl group having 2 to 11 carbon atoms in R ¹ include a methoxycarbonyl group, an ethoxycarbonyl group, an n-propoxycarbonyl group, an i-propoxycarbonyl group, an n-butoxycarbonyl group, 2-methylpropoxycarbonyl group, 1-methylpropoxycarbonyl group, t-butoxycarbonyl group, n-pentyloxycarbonyl group, neopentyloxycarbonyl group, n-hexyloxycarbonyl group, n-heptyloxycarbonyl group, n-octyl An oxycarbonyl group, 2-ethylhexyloxycarbonyl group, n-nonyloxycarbonyl group, n-decyloxycarbonyl group, etc. can be mentioned. Of these alkoxycarbonyl groups, a methoxycarbonyl group, an ethoxycarbonyl group, and an n-butoxycarbonyl group are preferable.

Examples of the linear, branched, or cyclic alkanesulfonyl group having 1 to 10 carbon atoms of R ² include a methanesulfonyl group, an ethanesulfonyl group, an n-propanesulfonyl group, an n-butanesulfonyl group, and a tert-butane. Sulfonyl group, n-pentanesulfonyl group, neopentanesulfonyl group, n-hexanesulfonyl group, n-heptanesulfonyl group, n-octanesulfonyl group, 2-ethylhexanesulfonyl group n-nonanesulfonyl group, n-decanesulfonyl group, A cyclopentanesulfonyl group, a cyclohexanesulfonyl group, etc. can be mentioned. Of these alkanesulfonyl groups, a methanesulfonyl group, an ethanesulfonyl group, an n-propanesulfonyl group, an n-butanesulfonyl group, a cyclopentanesulfonyl group, and a cyclohexanesulfonyl group are preferable.
Moreover, as m, 0-2 are preferable.

Examples of the optionally substituted phenyl group in R ³ include a phenyl group, o-tolyl group, m-tolyl group, p-tolyl group, 2,3-dimethylphenyl group, 2,4-dimethylphenyl group, 2,5-dimethylphenyl group, 2,6-dimethylphenyl group, 3,4-dimethylphenyl group, 3,5-dimethylphenyl group, 2,4,6-trimethylphenyl group, 4-ethylphenyl group, 4- a phenyl group such as a t-butylphenyl group, a 4-cyclohexylphenyl group, a 4-fluorophenyl group, or a phenyl group substituted with a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms; these phenyl groups Alternatively, an alkyl-substituted phenyl group can be replaced with a hydroxyl group, a carboxyl group, a cyano group, a nitro group, an alkoxyl group, an alkoxyalkyl group, an alkoxy group. Boniru group, and the like groups substituted with at least one group of one or more such alkoxycarbonyloxy groups.

Among the substituents for the phenyl group and the alkyl-substituted phenyl group, examples of the alkoxyl group include methoxy group, ethoxy group, n-propoxy group, i-propoxy group, n-butoxy group, 2-methylpropoxy group, 1- Examples thereof include straight-chain, branched or cyclic alkoxyl groups having 1 to 20 carbon atoms such as methylpropoxy group, t-butoxy group, cyclopentyloxy group and cyclohexyloxy group.
Examples of the alkoxyalkyl group include those having 2 to 21 carbon atoms such as a methoxymethyl group, an ethoxymethyl group, a 1-methoxyethyl group, a 2-methoxyethyl group, a 1-ethoxyethyl group, and a 2-ethoxyethyl group. Examples thereof include linear, branched or cyclic alkoxyalkyl groups. Examples of the alkoxycarbonyl group include a methoxycarbonyl group, an ethoxycarbonyl group, an n-propoxycarbonyl group, an i-propoxycarbonyl group, an n-butoxycarbonyl group, a 2-methylpropoxycarbonyl group, and a 1-methylpropoxycarbonyl group. , T-butoxycarbonyl group, cyclopentyloxycarbonyl group, cyclohexyloxycarbonyl and the like, and linear, branched or cyclic alkoxycarbonyl groups having 2 to 21 carbon atoms.
Examples of the alkoxycarbonyloxy group include methoxycarbonyloxy group, ethoxycarbonyloxy group, n-propoxycarbonyloxy group, i-propoxycarbonyloxy group, n-butoxycarbonyloxy group, t-butoxycarbonyloxy group, Examples thereof include linear, branched or cyclic alkoxycarbonyloxy groups having 2 to 21 carbon atoms such as cyclopentyloxycarbonyl group and cyclohexyloxycarbonyl.
Among the optionally substituted phenyl groups for R ³ , a phenyl group, a 4-cyclohexylphenyl group, a 4-t-butylphenyl group, a 4-methoxyphenyl group, and a 4-t-butoxyphenyl group are preferable. .

Examples of the optionally substituted naphthyl group in R ³ include 1-naphthyl group, 2-methyl-1-naphthyl group, 3-methyl-1-naphthyl group, 4-methyl-1-naphthyl group, 4- Methyl-1-naphthyl group, 5-methyl-1-naphthyl group, 6-methyl-1-naphthyl group, 7-methyl-1-naphthyl group, 8-methyl-1-naphthyl group, 2,3-dimethyl-1 -Naphthyl group, 2,4-dimethyl-1-naphthyl group, 2,5-dimethyl-1-naphthyl group, 2,6-dimethyl-1-naphthyl group, 2,7-dimethyl-1-naphthyl group, 2, 8-dimethyl-1-naphthyl group, 3,4-dimethyl-1-naphthyl group, 3,5-dimethyl-1-naphthyl group, 3,6-dimethyl-1-naphthyl group, 3,7-dimethyl-1- Naphthyl group, 3,8-dimethyl-1-naphth Group, 4,5-dimethyl-1-naphthyl group, 5,8-dimethyl-1-naphthyl group, 4-ethyl-1-naphthyl group, 2-naphthyl group, 1-methyl-2-naphthyl group, 3-methyl A naphthyl group substituted with a naphthyl group such as a 2-naphthyl group or 4-methyl-2-naphthyl group or a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms; these naphthyl groups or alkyl substitutions And a group in which a naphthyl group is substituted with at least one group such as a hydroxyl group, a carboxyl group, a cyano group, a nitro group, an alkoxyl group, an alkoxyalkyl group, an alkoxycarbonyl group, and an alkoxycarbonyloxy group. it can.
Examples of the alkoxyl group, alkoxyalkyl group, alkoxycarbonyl group, and alkoxycarbonyloxy group that are the above substituents include the groups exemplified for the phenyl group and the alkyl-substituted phenyl group.
Examples of the optionally substituted naphthyl group in R ³ include a 1-naphthyl group, a 1- (4-methoxynaphthyl) group, a 1- (4-ethoxynaphthyl) group, and a 1- (4-n-propoxynaphthyl) group. 1- (4-n-butoxynaphthyl) group, 2- (7-methoxynaphthyl) group, 2- (7-ethoxynaphthyl) group, 2- (7-n-propoxynaphthyl) group, 2- (7- n-Butoxynaphthyl) group is preferred.
R ³ is preferably a methyl group, an ethyl group, a phenyl group, a 4-methoxyphenyl group, or a 1-naphthyl group.

X represents a divalent group having 2 to 10 carbon atoms, and examples of the divalent group having 2 to 10 carbon atoms include a 5-membered or 6-membered ring together with the sulfur atom in formula (1) or formula (2). Particularly preferred is a group forming a 5-membered ring (that is, a tetrahydrothiophene ring). Examples of the substituent for the divalent group include a hydroxyl group, a carboxyl group, a cyano group, a nitro group, an alkoxyl group, an alkoxyalkyl group, an alkoxy group exemplified as the substituent for the phenyl group and the alkyl-substituted phenyl group. Examples thereof include a carbonyl group and an alkoxycarbonyloxy group.
X is preferably a divalent group that forms a tetrahydrothiophene ring structure with a sulfur atom.

Examples of the fluorinated alkyl group having 1 to 8 carbon atoms of R ⁴ , R ⁵ , R ^{4 ′} and R ^{5 ′} include perfluoro or partially fluorinated alkyl groups such as a trifluoromethyl group, Pentafluoroethyl group, heptafluoro-n-butyl group, heptafluoro-i-propyl group, nonafluoro-n-butyl group, nonafluoro-2-methylpropyl group, nonafluoro-1-methylpropyl group, nonafluoro-t-butyl group Perfluoro-n-pentyl group, perfluoronepentyl group, perfluoro-n-hexyl group, perfluoro-n-heptyl group, perfluoro-n-octyl group, and the like.
A fluorinated alkylene group having 2 to 8 carbon atoms bonded to each other of R ⁴ , a fluorinated alkylene group having 2 to 8 carbon atoms to which 2 R ⁵ are bonded, and 2 to 2 carbon atoms having 2 R ^{5 ′} bonded thereto; Specific examples of the fluorinated alkylene group 8 include perfluoro or partially fluorinated alkylene groups such as a tetrafluoroethylene group, 1,2-hexafluoropropylene group, and 1,3-hexafluoro group. Propylene group, 1,2-octafluorobutylene group, 1,3-octafluorobutylene group, 1,4-octafluorobutylene group, 2-trifluoromethyl-1,3-pentafluoropropylene group, 1,5-par Fluoropentylene group, 1,6-perfluorohexylene group, 1,7-perfluoroheptylene group, 1,8-perfluorooctylene group, etc. You can.

As a preferable thing of the cation part of the acid generator (B) represented by Formula (1)-(4), the following compound is mentioned.

Preferable examples of the anion moiety of the acid generator (B) represented by the formulas (1) to (4) include the following compounds.

上記の中で特に好ましいスルホニウム塩は、Ｂ１−１〜Ｂ１−３、Ｂ１−７〜Ｂ１−９、Ｂ１−１３〜Ｂ１−１５、Ｂ１−１９〜Ｂ１−２２、Ｂ１−２６〜Ｂ１−２９、Ｂ１−３３〜Ｂ１−３６である。これらは式（１）または式（３）で表されるスルホニウム塩である。 All combinations of the above cation moiety and anion moiety can be preferably used. Moreover, the sulfonium salt represented by a following formula is preferable.

Among the above, particularly preferred sulfonium salts are B1-1 to B1-3, B1-7 to B1-9, B1-13 to B1-15, B1-19 to B1-22, B1-26 to B1-29, B1-33 to B1-36. These are sulfonium salts represented by formula (1) or formula (3).

  As the acid generator used in the radiation sensitive resin composition of the present invention, other acid sensitive acid generators (hereinafter referred to as “other acid generators”) can be used in combination with the acid generator (B). Examples of other acid generators include triphenylsulfonium trifluoromethanesulfonate, tri-tert-butylphenylsulfonium trifluoromethanesulfonate, 4-cyclohexylphenyl-diphenylsulfonium trifluoromethanesulfonate, and 4-methanesulfonylphenyl-diphenylsulfonium trifluoromethanesulfonate. 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-n-butoxynaphthyl) tetrahydrothiophenium trifluoromethanesulfonate, triphenylsulfonium perfluoro-n-butane Sulfonate, tri-tert-butylphenylsulfonium perfluoro-n-butanesulfonate, 4 Cyclohexylphenyl-diphenylsulfonium perfluoro-n-butanesulfonate, 4-methanesulfonylphenyl-diphenylsulfonium perfluoro-n-butanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium perfluoro- n-butanesulfonate, 1- (4-n-butoxynaphthyl) tetrahydrothiophenium perfluoro-n-butanesulfonate, triphenylsulfonium perfluoro-n-octanesulfonate, tri-tert-butylphenylsulfonium perfluoro-n- Octanesulfonate, 4-cyclohexylphenyl-diphenylsulfonium perfluoro-n-octanesulfonate, 4-methanesulfonylphenyl-diphenylsulfone Umperfluoro-n-octane sulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium perfluoro-n-octane sulfonate, 1- (4-n-butoxynaphthyl) tetrahydrothiophenium per Fluoro-n-octanesulfonate, triphenylsulfonium 2- (bicyclo [2.2.1] hepta-2'-yl) -1,1,2,2-tetrafluoroethanesulfonate, tri-tert-butylphenylsulfonium 2 -(Bicyclo [2.2.1] hepta-2'-yl) -1,1,2,2-tetrafluoroethanesulfonate, 4-cyclohexylphenyl-diphenylsulfonium 2- (bicyclo [2.2.1] hepta -2'-yl) -1,1,2,2-tetrafluoroethanesulfonate 4-methanesulfonylphenyl-diphenylsulfonium 2- (bicyclo [2.2.1] hepta-2'-yl) -1,1,2,2-tetrafluoroethanesulfonate, 1- (3,5-dimethyl- 4-hydroxyphenyl) tetrahydrothiophenium 2- (bicyclo [2.2.1] hepta-2'-yl) -1,1,2,2-tetrafluoroethanesulfonate, 1- (4-n-butoxynaphthyl) ) Tetrahydrothiophenium 2- (bicyclo [2.2.1] hepta-2'-yl) -1,1,2,2-tetrafluoroethanesulfonate, triphenylsulfonium 2- (bicyclo [2.2.1] ] Hepta-2'-yl) -1,1-difluoroethanesulfonate, tri-tert-butylphenylsulfonium 2- (bicyclo [2.2.1] hept Ta-2′-yl) -1,1-difluoroethanesulfonate, 4-cyclohexylphenyl-diphenylsulfonium 2- (bicyclo [2.2.1] hepta-2′-yl) -1,1-difluoroethanesulfonate, 4- Methanesulfonylphenyl-diphenylsulfonium 2- (bicyclo [2.2.1] hepta-2'-yl) -1,1-difluoroethanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium 2- (bicyclo [2.2.1] hepta-2'-yl) -1,1-difluoroethanesulfonate, 1- (4-n-butoxynaphthyl) tetrahydrothiophenium 2- (bicyclo [2.2.1] ] Hepta-2'-yl) -1,1-difluoroethanesulfonate, diphenyliodonium triflate L-methanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, diphenyliodonium perfluoro-n-octanesulfonate, diphenyliodonium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetra Fluoroethanesulfonate, bis (4-t-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-t-butylphenyl) iodonium nonafluoro-n-butanesulfonate, bis (4-t-butylphenyl) iodonium perfluoro-n Octane sulfonate, bis (4-t-butylphenyl) iodonium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethane sulfonate, cyclohexyl 2-oxocyclohexane Xylmethylsulfonium trifluoromethanesulfonate, dicyclohexyl-2-oxocyclohexylsulfonium trifluoromethanesulfonate, 2-oxocyclohexyldimethylsulfonium trifluoromethanesulfonate,

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, 2-bicyclo [2.2.1] hept-2-yl-1,1,2 , 2-tetrafluoroethanesulfonylbicyclo [2.2.1] hept-5-ene-2,3-dicarbodiimide, N- (trifluoromethanesulfonyloxy) succinimide, N- (nonafluoro-n-butanesulfonyloxy) succinimide N- (perfluoro-n-octanesulfonyloxy) succinimide, N- (2-bicyclo [2.2 1] hept-2-yl-1,1,2,2-tetrafluoroethane sulfonyloxy) succinimide, 1,8-naphthalenedicarboxylic acid imide trifluoromethanesulfonate, and the like.
Other acid generators can be used in combination with the acid generator (B) alone or in admixture of two or more.

  In the present invention, the total amount of the acid generator (B) containing other acid generator is a resin described later from the viewpoint of sensitivity as a resist, developability, and suppression of elution from the composition into the immersion liquid. (A) It is 0.1-20 mass parts normally with respect to 100 mass parts, Preferably it is 0.5-10 mass parts. In this case, if the amount used is less than 0.1 parts by mass, the sensitivity and developability tend to decrease. On the other hand, if it exceeds 20 parts by mass, the transparency to radiation decreases and it is difficult to obtain a rectangular resist pattern. Therefore, the elution suppression effect tends to be lost. Moreover, the usage-amount of another acid generator is 80 mass% or less normally with respect to the sum total of an acid generator (B) and another acid generator, Preferably it is 60 mass% or less.

Resin (A)
The resin that can be used in the present invention is a resin (A) containing acid labile groups [hereinafter referred to as “resin (A)”]. The resin (A) is not particularly limited, but preferably includes a repeating unit containing a skeleton represented by the following formula (5) (hereinafter referred to as “repeating unit (1)”) as an essential unit. It is an alkali-insoluble or hardly alkali-soluble resin that contains and becomes alkali-soluble by the action of an acid. The term “alkali insoluble or alkali insoluble” as used herein refers to an alkali development condition employed when forming a resist pattern from a resist film formed from a radiation-sensitive resin composition containing the resin (A). When a film using only the resin (A) is developed in place of the resist film, it means that 50% or more of the initial film thickness of the film remains after development.

式（５）において、Ｒ⁶は水素原子、メチル基、またはトリフルオロメチル基を表し、Ｒ⁷は炭素数１〜４の直鎖状もしくは分岐状のアルキル基を表す。
Ｒ⁷の炭素数１〜４の直鎖状もしくは分岐状のアルキル基としては、例えば、メチル基、エチル基、ｎ−プロピル基、ｉ−プロピル基、ｎ−ブチル基、２−メチルプロピル基、１−メチルプロピル基、ｔ−ブチル基等を挙げることができる。これらのアルキル基のうち、メチル基、エチル基、ｎ−プロピル基、ｉ−プロピル基が好ましい。

In Formula (5), R ⁶ represents a hydrogen atom, a methyl group, or a trifluoromethyl group, and R ⁷ represents a linear or branched alkyl group having 1 to 4 carbon atoms.
Examples of the linear or branched alkyl group having 1 to 4 carbon atoms of R ⁷ include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a 2-methylpropyl group, Examples thereof include 1-methylpropyl group and t-butyl group. Of these alkyl groups, a methyl group, an ethyl group, an n-propyl group, and an i-propyl group are preferable.

  As preferred repeating units (1), (meth) acrylic acid 1-methyl-1-cyclopentyl ester, (meth) acrylic acid 1-ethyl-1-cyclopentyl ester, (meth) acrylic acid 1-propyl-1-cyclopentyl ester (Meth) acrylic acid 1-i-propyl-1-cyclopentyl ester, etc., and (meth) acrylic acid 1-methyl-1-cyclopentyl ester, (meth) acrylic acid 1-ethyl-1- And cyclopentyl ester.

式（ｆ−１）〜式（ｆ−６）の各式において、Ｒ⁸は水素原子または炭素数１〜４の置換基を有してもよいアルキル基を表し、Ｒ⁹は水素原子またはメトキシ基を表す。Ａは単結合またはメチレン基を表し、Ｂは酸素原子またはメチレン基を表す。ｌは１〜３の整数を示し、ｍ’は０または１である。
式（ｆ−１）におけるＲ⁸の炭素数１〜４の置換基を有していてもよいアルキル基を表し、具体的には、メチル基、エチル基、ｎ−プロピル基、ｉ−プロピル基、ｎ−ブチル基、メトキシメチル基、エトキシメチル基、メトキシエチル基、エトキシエチル基、メトキシカルボニルメチル基、メトキシカルボニルエチル基等が挙げられる。
なお、繰り返し単位（２）の主鎖骨格は特に限定されるものではないが、好ましくは、メタクリル酸エステル、アクリル酸エステルあるいはαトリフルオロアクリル酸エステル構造を有する。また、本明細書中、「（メタ）アクリル酸エステル」とはアクリル酸エステルおよびメタクリル酸エステルの双方を意味する。 The resin (A) in the present invention is a repeating unit derived from a lactone as a polar group (hereinafter referred to as “repeating unit (2)”) or a repeating unit represented by the following formula (6) (hereinafter referred to as “ It is preferable to contain at least one repeating unit selected from repeating unit (3) ”.
The repeating unit (2) preferably contains a repeating unit having a lactone structure represented by the following formulas (f-1) to (f-6) in the side chain.

In the formulas (f-1) to (f-6), R ⁸ represents a hydrogen atom or an alkyl group which may have a substituent having 1 to 4 carbon atoms, and R ⁹ represents a hydrogen atom or methoxy. Represents a group. A represents a single bond or a methylene group, and B represents an oxygen atom or a methylene group. l represents an integer of 1 to 3, and m ′ is 0 or 1.
In the formula (f-1), R ⁸ represents an alkyl group which may have a substituent having 1 to 4 carbon atoms, specifically a methyl group, an ethyl group, an n-propyl group, an i-propyl group. N-butyl group, methoxymethyl group, ethoxymethyl group, methoxyethyl group, ethoxyethyl group, methoxycarbonylmethyl group, methoxycarbonylethyl group and the like.
The main chain skeleton of the repeating unit (2) is not particularly limited, but preferably has a methacrylic acid ester, acrylic acid ester or α-trifluoroacrylic acid ester structure. Moreover, in this specification, "(meth) acrylic acid ester" means both acrylic acid ester and methacrylic acid ester.

Preferred among the repeating units (2) are (meth) acrylic acid-5-oxo-4-oxa-tricyclo [4.2.1.0 ^3,7 ] non-2-yl ester, (meth) acrylic. Acid-9-methoxycarbonyl-5-oxo-4-oxa-tricyclo [4.2.1.0 ^3,7 ] non-2-yl ester, (meth) acrylic acid-5-oxo-4-oxa-tricyclo [5.2.1.0 ^3,8 ] dec-2-yl ester, (meth) acrylic acid-10-methoxycarbonyl-5-oxo-4-oxa-tricyclo [5.2.1.0 ^3,8 Nona-2-yl ester, (meth) acrylic acid-6-oxo-7-oxa-bicyclo [3.2.1] oct-2-yl ester, (meth) acrylic acid-4-methoxycarbonyl-6 Oxo-7-oxa-bicyclo [3.2. ] Oct-2-yl ester, (meth) acrylic acid-7-oxo-8-oxa-bicyclo [3.3.1] oct-2-yl ester, (meth) acrylic acid-4-methoxycarbonyl-7- Oxo-8-oxa-bicyclo [3.3.1] oct-2-yl ester, (meth) acrylic acid-2-oxotetrahydropyran-4-yl ester, (meth) acrylic acid-4-methyl-2- Oxotetrahydropyran-4-yl ester, (meth) acrylic acid-4-ethyl-2-oxotetrahydropyran-4-yl ester, (meth) acrylic acid-4-propyl-2-oxotetrahydropyran-4-yl ester , (Meth) acrylic acid-5-oxotetrahydrofuran-3-yl ester, (meth) acrylic acid-2,2-dimethyl-5-oxoteto Lahydrofuran-3-yl ester, (meth) acrylic acid-4,4-dimethyl-5-oxotetrahydrofuran-3-yl ester, (meth) acrylic acid-2-oxotetrahydrofuran-3-yl ester, (meth) acrylic acid -4,4-dimethyl-2-oxotetrahydrofuran-3-yl ester, (meth) acrylic acid-5,5-dimethyl-2-oxotetrahydrofuran-3-yl ester, (meth) acrylic acid-2-oxotetrahydrofuran 3-yl ester, (meth) acrylic acid-5-oxotetrahydrofuran-2-ylmethyl ester, (meth) acrylic acid-3,3-dimethyl-5-oxotetrahydrofuran-2-ylmethyl ester, (meth) acrylic acid -4,4-dimethyl-5-oxotetrahydrofuran-2- Methyl ester.

式（６）において、Ｒ¹⁰は水素原子、炭素数１〜４のアルキル基、トリフルオロメチル基、またはヒドロキシメチル基を表す。炭素数１〜４のアルキル基としては、例えば、メチル基、エチル基、ｎ−プロピル基、ｉ−プロピル基、ｎ−ブチル基、２−メチルプロピル基、１−メチルプロピル基、ｔ−ブチル基等のアルキル基が挙げられる。
Ｒ¹¹は２価の有機基を表す。２価の有機基は、好ましくは２価の炭化水素基であり、２価の炭化水素基の中でも好ましくは鎖状または環状の炭化水素基が好ましく、アルキレングリコール基、アルキレンエステル基であってもよい。
好ましいＲ¹¹としては、メタン、エタン、プロパン、ブタン、イソブタン、ペンタン、イソペンタン、ネオペンタン、ヘキサン、２−メチルヘキサン、３−メチルヘキサン等の直鎖状、分岐状の炭化水素に由来する２価の有機基、シクロブタン、シクロペンタン、シクロヘキサン、ビシクロ［２．２．１］ヘプタン、２-メチルビシクロ［２．２．１］ヘプタン、ビシクロ［２．２．２］オクタン、２-メチルビシクロ［２．２．２］オクタン、トリシクロ［５．２．１．０^2,6］デカン、８‐メチルトリシクロ［５．２．１．０^2,6］デカン、テトラシクロ［６．２．１．１^3,6．０^2,7］ドデカン、９‐メチルテトラシクロ［６．２．１．１^3,6．０^2,7］ドデカン、トリシクロ［３．３．１．１^3,7］デカン、１‐メチルトリシクロ［３．３．１．１^3,7］デカン、２‐メチルトリシクロ［３．３．１．１^3,7］デカン等炭素数４〜３０の脂環式炭化水素に由来する２価の有機基が挙げられる。 The repeating unit (3) is represented by the following formula (6).

In Formula (6), R ¹⁰ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a trifluoromethyl group, or a hydroxymethyl group. Examples of the alkyl group having 1 to 4 carbon atoms include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, 2-methylpropyl group, 1-methylpropyl group, and t-butyl group. And the like.
R ¹¹ represents a divalent organic group. The divalent organic group is preferably a divalent hydrocarbon group, and a divalent hydrocarbon group is preferably a chain or cyclic hydrocarbon group, and may be an alkylene glycol group or an alkylene ester group. Good.
Preferable R ¹¹ is divalent derived from a linear or branched hydrocarbon such as methane, ethane, propane, butane, isobutane, pentane, isopentane, neopentane, hexane, 2-methylhexane, and 3-methylhexane. Organic group, cyclobutane, cyclopentane, cyclohexane, bicyclo [2.2.1] heptane, 2-methylbicyclo [2.2.1] heptane, bicyclo [2.2.2] octane, 2-methylbicyclo [2. 2.2] octane, tricyclo [5.2.1.0 ^2,6 ] decane, 8-methyltricyclo [5.2.1.0 ^2,6 ] decane, tetracyclo [6.2.1.1 ^{3 , 6} . 0 ^2,7 ] dodecane, 9-methyltetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] dodecane, tricyclo [3.3.1.1 ^3,7 ] decane, 1-methyltricyclo [3.3.1.1 ^3,7 ] decane, 2-methyltricyclo [3.3 .1.1 ^3,7], and divalent organic group derived from alicyclic hydrocarbons decane 4 to 30 carbon atoms.

Particularly preferred repeating units (3) are (meth) acrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-3-propyl) ester, (meth) acrylic acid (1,1, 1-trifluoro-2-trifluoromethyl-2-hydroxy-4-butyl) ester, (meth) acrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-5-pentyl) Ester, (meth) acrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-4-pentyl) ester, (meth) acrylic acid 2-{[5- (1 ′, 1 ′ , 1′-trifluoro-2′-trifluoromethyl-2′-hydroxy) propyl] bicyclo [2.2.1] heptyl} ester, (meth) acrylic acid 3-{[8- (1 ′, 1 ′ , 1′-trifluoro-2′-trifluoromethyl-2′-hydroxy) propyl] tetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] dodecyl} ester and the like.
The resin (A) in the present invention can contain two or more kinds of repeating units selected from the repeating unit (2) and the repeating unit (3).

式（７）において、Ｒ¹²は水素原子、メチル基、あるいはトリフルオロメチル基を表し、Ｒ¹³は炭素数１〜４の直鎖状もしくは分岐状のアルキル基を表す。
式（７）におけるＲ¹³の炭素数１〜４の直鎖状もしくは分岐状のアルキル基としては、例えば、メチル基、エチル基、ｎ−プロピル基、ｉ−プロピル基、ｎ−ブチル基、２−メチルプロピル基、１−メチルプロピル基、ｔ−ブチル基等を挙げることができる。これらのアルキル基のうち、メチル基、エチル基、ｎ−プロピル基、ｉ−プロピル基が好ましい。
好ましい繰り返し単位（４）としては、（メタ）アクリル酸２−メチルアダマンチル−２−イルエステル、（メタ）アクリル酸２−メチル−３−ヒドロキシアダマンチル−２−イルエステル、（メタ）アクリル酸２−エチルアダマンチル−２−イルエステル、（メタ）アクリル酸２−エチル−３−ヒドロキシアダマンチル−２−イルエステル、（メタ）アクリル酸２−ｎ−プロピルアダマンチル−２−イルエステル、（メタ）アクリル酸２−イソプロピルアダマンチル−２−イルエステルが挙げられる。 In addition to the repeating unit (1), the repeating unit (2) and the repeating unit (3), the resin (A) in the present invention contains a repeating unit represented by the following formula (7) (hereinafter referred to as “repeating unit ( 4) ")).

In the formula (7), R ¹² represents a hydrogen atom, a methyl group, or a trifluoromethyl group, and R ¹³ represents a linear or branched alkyl group having 1 to 4 carbon atoms.
Examples of the linear or branched alkyl group having 1 to 4 carbon atoms of R ¹³ in the formula (7) include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, 2 -Methylpropyl group, 1-methylpropyl group, t-butyl group and the like can be mentioned. Of these alkyl groups, a methyl group, an ethyl group, an n-propyl group, and an i-propyl group are preferable.
Preferred repeating units (4) include (meth) acrylic acid 2-methyladamantyl-2-yl ester, (meth) acrylic acid 2-methyl-3-hydroxyadamantyl-2-yl ester, (meth) acrylic acid 2- Ethyladamantyl-2-yl ester, (meth) acrylic acid 2-ethyl-3-hydroxyadamantyl-2-yl ester, (meth) acrylic acid 2-n-propyladamantyl-2-yl ester, (meth) acrylic acid 2 -Isopropyladamantyl-2-yl ester.

式（８）において、Ｒ¹⁴は水素原子、メチル基、あるいはトリフルオロメチル基を表し、Ｘ’は炭素数７〜２０の多環型脂環式炭化水素基であり、この炭素数７〜２０の多環型脂環式炭化水素基は、炭素数１〜４のアルキル基、ヒドロキシル基、シアノ基、炭素数１〜１０のヒドロキシアルキル基で置換されていても、置換されていなくてもよい。
式（８）で表される他の繰り返し単位（５）のＸ’としては、好ましくは、炭素数７〜２０の多環型脂環式炭化水素基である。このような多環型脂環式炭化水素基としては、例えば、下記式に示すように、ビシクロ［２．２．１］ヘプタン（ａ）、ビシクロ［２．２．２］オクタン（ｂ）、トリシクロ［５．２．１．０^2,6］デカン（ｃ）、テトラシクロ［６．２．１．１^3,6．０^2,7］ドデカン（ｄ）、トリシクロ［３．３．１．１^3,7］デカン（ｅ）等のシクロアルカン類に由来する脂環族環からなる炭化水素基が挙げられる。

In addition to the repeating unit (1), the repeating unit (2), the repeating unit (3), and the repeating unit (4), the resin (A) in the present invention is further represented by the following repeating unit (8) , "Repeated unit (5)").

In the formula (8), R ¹⁴ represents a hydrogen atom, a methyl group, or a trifluoromethyl group, and X ′ is a polycyclic alicyclic hydrocarbon group having 7 to 20 carbon atoms. The polycyclic alicyclic hydrocarbon group may be substituted or unsubstituted with an alkyl group having 1 to 4 carbon atoms, a hydroxyl group, a cyano group, or a hydroxyalkyl group having 1 to 10 carbon atoms. .
X ′ of the other repeating unit (5) represented by the formula (8) is preferably a polycyclic alicyclic hydrocarbon group having 7 to 20 carbon atoms. Examples of such polycyclic alicyclic hydrocarbon groups include bicyclo [2.2.1] heptane (a), bicyclo [2.2.2] octane (b), as shown in the following formula: Tricyclo [5.2.1.0 ^2,6 ] decane (c), tetracyclo [6.2.1.1 ^3,6 . Hydrocarbon groups composed of alicyclic rings derived from cycloalkanes such as 0 ^2,7 ] dodecane (d) and tricyclo [3.3.1.1 ^3,7 ] decane (e).

These cycloalkane-derived alicyclic rings may have a substituent, for example, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, 2-methylpropyl group. , 1-methylpropyl group, t-butyl group and the like, or a linear, branched or cyclic alkyl group having 1 to 4 carbon atoms may be substituted with one or more. These are represented by the following specific examples, but are not limited to those substituted by these alkyl groups, but are hydroxyl groups, cyano groups, C1-C10 hydroxyalkyl groups, carboxyls. The group may be substituted with oxygen. Moreover, these other repeating units (5) can contain 1 type (s) or 2 or more types.
The repeating unit (5) is preferably (meth) acrylic acid-bicyclo [2.2.1] hept-2-yl ester, (meth) acrylic acid-bicyclo [2.2.2] oct-2- Yl ester, (meth) acrylic acid-tricyclo [5.2.1.0 ^2,6 ] dec-7-yl ester, (meth) acrylic acid-tetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] dodec-9-yl ester, (meth) acrylic acid-tricyclo [3.3.1.1 ^3,7 ] dec-1-yl ester, (meth) acrylic acid-tricyclo [3.3. ^1.1,7 ] Dec-2-yl ester and the like.

As repeating units other than the above formulas (1) to (5), for example, (meth) acrylic acid 2-methyladamantyl-2-yl ester, (meth) acrylic acid 2-methyl-3-hydroxyadamantyl-2-yl ester (Meth) acrylic acid 2-ethyladamantyl-2-yl ester, (meth) acrylic acid 2-ethyl-3-hydroxyadamantyl-2-yl ester, (meth) acrylic acid 2-n-propyladamantyl-2-yl ester Ester, (meth) acrylic acid 2-isopropyladamantyl-2-yl ester, (meth) acrylic acid-2-methylbicyclo [2.2.1] hept-2-yl ester, (meth) acrylic acid-2-ethyl ester Bicyclo [2.2.1] hept-2-yl ester, (meth) acrylic acid-8-methyltricyclo [5.2.1] 0 ^2,6] decan-8-yl ester, (meth) ethyl-8-acrylic acid tricyclo [5.2.1.0 ^2,6] decan-8-yl ester, (meth) acrylic acid-4- Methyltetracyclo [6.2.1 ^3,6 . 0 ^2,7 ] dodecan-4-yl ester, (meth) acrylic acid-4-ethyltetracyclo [6.2.1 ^3,6 . 0 ^2,7 ] dodecan-4-yl ester, (meth) acrylic acid 1- (bicyclo [2.2.1] hept-2-yl) -1-methylethyl ester, (meth) acrylic acid 1- (tricyclo [5.2.1.0 ^2,6 ] decan-8-yl) -1-methylethyl ester, (meth) acrylic acid 1- (tetracyclo [6.2.1 ^3,6 .0 ^2,7 ] dodecane -4-yl) -1-methylethyl ester, (meth) acrylic acid 1- (adamantan-1-yl) -1-methylethyl ester, (meth) acrylic acid 1- (3-hydroxyadamantan-1-yl) -1-methyl ethyl ester, (meth) acrylic acid 1,1-dicyclohexylethyl ester, (meth) acrylic acid 1,1-di (bicyclo [2.2.1] hept-2-yl) ethyl ester, (Meth) acrylic 1,1-di (tricyclo [5.2.1.0 ^2,6] decan-8-yl) ethyl ester, (meth) acrylic acid 1,1-di (tetracyclo [6.2.1 ^3,6. 0 ^2,7 ] dodecan-4-yl) ethyl ester, (meth) acrylic acid 1,1-di (adamantan-1-yl) ethyl ester, (meth) acrylic acid 1-methyl-1-cyclohexyl ester, (meth ) 1-ethyl-1-cyclohexyl ester of acrylic acid,

(Meth) acrylic acid 2-methyladamantyl-2-yl ester, (meth) acrylic acid 2-ethyladamantyl-2-yl ester, (meth) acrylic acid-2-methylbicyclo [2.2.1] hept-2 -Yl ester, (meth) acrylic acid-2-ethylbicyclo [2.2.1] hept-2-yl ester, (meth) acrylic acid 1- (bicyclo [2.2.1] hept-2-yl) -1-methylethyl ester, (meth) acrylic acid 1- (adamantan-1-yl) -1-methylethyl ester, (meth) acrylic acid 3-hydroxyadamantan-1-ylmethyl ester, (meth) acrylic acid 3 , 5-dihydroxyadamantan-1-ylmethyl ester, (meth) acrylic acid 3-hydroxy-5-methyladamantan-1-yl ester, (Meth) acrylic acid 3,5-dihydroxy-7-methyladamantan-1-yl ester, (meth) acrylic acid 3-hydroxy-5,7-dimethyladamantan-1-yl ester, (meth) acrylic acid 3-hydroxy- 5,7-dimethyladamantan-1-ylmethyl ester,

Carboxynorbornyl (meth) acrylate, carboxytricyclodecanyl (meth) acrylate, carboxytetracycloundecanyl (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, (meth) N-propyl acrylate, n-butyl (meth) acrylate, 2-methylpropyl (meth) acrylate, 1-methylpropyl (meth) acrylate, t-butyl (meth) acrylate, (meth) acrylic acid 2 -Hydroxyethyl, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, cyclopropyl (meth) acrylate, cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, (meth) acryl 4-methoxycyclohexyl acid, 2-cyclope (meth) acrylic acid Chill oxycarbonyl ethyl, (meth) 2-cyclohexyloxycarbonylethyl acrylate, (meth) acrylic acid 2- (4-methoxy-cyclohexyl) oxycarbonyl ethyl,

α-hydroxymethyl methyl acrylate, α-hydroxymethyl ethyl acrylate, α-hydroxymethyl acrylate n-propyl, α-hydroxymethyl acrylate n-butyl, (meth) acrylonitrile, α-chloroacrylonitrile, crotonnitrile, malein Nitrile, Fumaronitrile, Mesaconnitrile, Citraconnitrile, Itaconnitrile, (Meth) acrylamide, N, N-dimethyl (meth) acrylamide, Crotonamide, Maleinamide, Fumaramide, Mesaconamide, Citraconamide, Itaconamide, N- (Meth) Acryloylmorpholine, N-vinyl-ε-caprolactam, N-vinylpyrrolidone, vinylpyridine, vinylimidazole, (meth) acrylic acid, crotonic acid, maleic acid, maleic anhydride, Malic acid, itaconic acid, itaconic anhydride, citraconic acid, citraconic anhydride, mesaconic acid, 2-carboxyethyl (meth) acrylate, 2-carboxypropyl (meth) acrylate, 3-carboxypropyl (meth) acrylate, (Meth) acrylic acid 4-carboxybutyl, (meth) acrylic acid 4-carboxycyclohexyl,

5-hydroxyacenaphthylene, 1-vinylnaphthalene, 2-vinylnaphthalene, 2-hydroxy-6-vinylnaphthalene, 1-naphthyl (meth) acrylate, 2-naphthyl (meth) acrylate, 1-naphthylmethyl (meth) acrylate 1-anthryl (meth) acrylate, 2-anthryl (meth) acrylate, 9-anthryl (meth) acrylate, 9-anthrylmethyl (meth) acrylate, 1-vinylpyrene,

1,2-adamantanediol di (meth) acrylate, 1,3-adamantanediol di (meth) acrylate, 1,4-adamantanediol di (meth) acrylate, tricyclodecanyl dimethylol di (meth) acrylate, etc. A polyfunctional monomer having a bridged hydrocarbon skeleton;

Methylene glycol di (meth) acrylate, ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 2,5-dimethyl-2,5-hexanediol di ( (Meth) acrylate, 1,8-octanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, 1,4-bis (2-hydroxypropyl) benzenedi (meth) acrylate, 1,3-bis List units in which a polymerizable unsaturated bond of a polyfunctional monomer such as a polyfunctional monomer having no bridged hydrocarbon skeleton such as (2-hydroxypropyl) benzenedi (meth) acrylate is cleaved Can do.
Among these repeating units other than the above formulas (1) to (5), a unit in which a polymerizable unsaturated bond of (meth) acrylic acid ester having a bridged hydrocarbon skeleton is cleaved is preferable.

In resin (A), the content rate of repeating unit (1) is 10-70 mol% normally with respect to all the repeating units, Preferably it is 10-60 mol%. In this case, if the content of the repeating unit (1) is less than 10 mol%, the resolution as a resist may be lowered. On the other hand, if it exceeds 70 mol%, the exposure margin may be deteriorated.
Moreover, the content rate of the whole repeating unit (2) and repeating unit (3) is 10-80 mol% normally with respect to all the repeating units, Preferably it is 15-80 mol%, More preferably, it is 20-70 mol%. is there. In this case, when the total content of the repeating unit (2) and the repeating unit (3) is less than 10 mol%, the resist has poor solubility in an alkaline developer, which contributes to development defects and deteriorates the exposure margin. There is a risk. The exposure margin indicates a change in line width with respect to a change in exposure amount. On the other hand, if it exceeds 70 mol%, the solubility of the resist in the solvent is lowered, and the resolution may be lowered.
Moreover, the content rate of a repeating unit (4) is 50 mol% or less normally with respect to all the repeating units, Preferably it is 45 mol% or less. In this case, if the content of the repeating unit (4) exceeds 35 mol%, the resolution and exposure margin of the resist may be reduced.
Moreover, the content rate of a repeating unit (5) is 30 mol% or less normally with respect to all the repeating units, Preferably it is 25 mol% or less. In this case, if the content of the repeating unit (4) exceeds 30 mol%, the resolution of the resist may be deteriorated.
Furthermore, the content of other repeating units is usually 50 mol% or less, preferably 40 mol% or less, based on all repeating units.

  Resin (A) uses, for example, a polymerizable unsaturated monomer corresponding to each repeating unit using a radical polymerization initiator such as hydroperoxides, dialkyl peroxides, diacyl peroxides, and azo compounds. If necessary, it can be produced by polymerization in an appropriate solvent in the presence of a chain transfer agent. Examples of the solvent used for polymerization include alkanes such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane, and n-decane; cyclohexane, cycloheptane, cyclooctane, decalin, norbornane. Cycloalkanes such as benzene, toluene, xylene, ethylbenzene, cumene and other aromatic hydrocarbons; chlorobutanes, bromohexanes, dichloroethanes, halogenated hydrocarbons such as hexamethylene dibromide, chlorobenzene; ethyl acetate, Saturated carboxylic acid esters such as n-butyl acetate, i-butyl acetate and methyl propionate; ketones such as acetone, 2-butanone, 4-methyl-2-pentanone and 2-heptanone; tetrahydrofuran, dimethoxyethanes, di List ethers such as ethoxyethanes Rukoto can. These solvents can be used alone or in admixture of two or more. Moreover, the reaction temperature in superposition | polymerization is 40-150 degreeC normally, Preferably it is 50-120 degreeC, and reaction time is 1-48 hours normally, Preferably it is 1-24 hours.

  The polystyrene-reduced mass average molecular weight (hereinafter referred to as “Mw”) by gel permeation chromatography (GPC) of the resin (A) is not particularly limited, but is preferably 1000 to 100,000, more preferably 1000 to 30000, more preferably. 1000-20000. In this case, if the Mw of the resin (A) is less than 1000, the heat resistance when used as a resist tends to be reduced, whereas if it exceeds 100,000, the developability when used as a resist tends to be reduced. The ratio (Mw / Mn) of Mw of the resin (A) to polystyrene-reduced number average molecular weight (hereinafter referred to as “Mn”) by gel permeation chromatography (GPC) is usually 1 to 5, preferably 1. ~ 3.

Moreover, in resin (A) in this invention, content of the low molecular weight component derived from the monomer used when preparing this resin (A) is solid content conversion with respect to 100 mass% of this resin. It is preferable that it is 0.1 mass% or less, More preferably, it is 0.07 mass% or less, More preferably, it is 0.05 mass% or less. When this content is 0.1% by mass or less, it is possible to reduce the amount of the eluate in water that is in contact with the immersion exposure. Further, no foreign matter is generated in the resist during storage of the resist, and coating unevenness does not occur during resist application, and the occurrence of defects during resist pattern formation can be sufficiently suppressed.
Examples of the low molecular weight component derived from the monomer include a monomer, a dimer, a trimer, and an oligomer, and can be a component having an Mw of 500 or less. The components having an Mw of 500 or less can be removed by, for example, chemical purification methods such as washing with water and liquid-liquid extraction, or a combination of these chemical purification methods and physical purification methods such as ultrafiltration and centrifugation. it can. Moreover, it can analyze by the high performance liquid chromatography (HPLC) of resin.
In addition, resin (A) is so preferable that there are few impurities, such as a halogen and a metal, Thereby, the sensitivity, resolution, process stability, pattern shape, etc. when it is set as a resist can be improved further. Examples of the purification method of the resin (A) include chemical purification methods such as washing with water and liquid-liquid extraction, and combinations of these chemical purification methods with physical purification methods such as ultrafiltration and centrifugation, etc. Can be mentioned. In this invention, resin (A) can be used individually or in mixture of 2 or more types.

The radiation-sensitive resin composition used for the immersion exposure of the present invention contains other components such as a nitrogen-containing compound (C) described below together with the resin (A) and the radiation-sensitive acid generator (B). be able to.
Nitrogen-containing compound (C)
The nitrogen-containing compound (C) used in the present invention acts as an acid diffusion control agent that controls the diffusion phenomenon in the resist film of the acid generated from the acid generator upon exposure and suppresses undesirable chemical reactions in non-exposed areas. To do. By blending such an acid diffusion controller, the storage stability of the resulting radiation-sensitive resin composition is improved, the resolution as a resist is further improved, and the process from exposure to heat treatment after exposure is improved. A change in the line width of the resist pattern due to fluctuations in the placement time (PED) can be suppressed, and a composition having extremely excellent process stability can be obtained.
Examples of the acid diffusion controller include “tertiary amine compound”, “amide group-containing compound”, “quaternary ammonium hydroxide compound”, “other nitrogen-containing heterocyclic compound” and the like.
Examples of the “tertiary amine compound” include triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine, tri-n-heptylamine, tri-n. -Tri (cyclo) alkylamines such as octylamine, cyclohexyldimethylamine, dicyclohexylmethylamine, tricyclohexylamine; aniline, N-methylaniline, N, N-dimethylaniline, 2-methylaniline, 3-methylaniline, 4 -Aromatic amines such as methylaniline, 4-nitroaniline, 2,6-dimethylaniline, 2,6-diisopropylaniline; alkanolamines such as triethanolamine, N, N-di (hydroxyethyl) aniline; N , N, N ', N'-Tetramethylethylene Amine, N, N, N ′, N′-tetrakis (2-hydroxypropyl) ethylenediamine, 1,3-bis [1- (4-aminophenyl) -1-methylethyl] benzenetetramethylenediamine, bis (2- Examples thereof include dimethylaminoethyl) ether and bis (2-diethylaminoethyl) ether.

  Examples of the “amide group-containing compound” include Nt-butoxycarbonyldi-n-octylamine, Nt-butoxycarbonyldi-n-nonylamine, Nt-butoxycarbonyldi-n-decylamine, Nt- Butoxycarbonyldicyclohexylamine, Nt-butoxycarbonyl-1-adamantylamine, Nt-butoxycarbonyl-2-adamantylamine, Nt-butoxycarbonyl-N-methyl-1-adamantylamine, (S)-( -)-1- (t-butoxycarbonyl) -2-pyrrolidinemethanol, (R)-(+)-1- (t-butoxycarbonyl) -2-pyrrolidinemethanol, Nt-butoxycarbonyl-4-hydroxypiperidine Nt-butoxycarbonylpyrrolidine, Nt-butoxycarbonylpipe Gin, N, N-di-t-butoxycarbonyl-1-adamantylamine, N, N-di-t-butoxycarbonyl-N-methyl-1-adamantylamine, Nt-butoxycarbonyl-4,4′- Diaminodiphenylmethane, N, N′-di-t-butoxycarbonylhexamethylenediamine, N, N, N′N′-tetra-t-butoxycarbonylhexamethylenediamine, N, N′-di-t-butoxycarbonyl-1 , 7-diaminoheptane, N, N′-di-t-butoxycarbonyl-1,8-diaminooctane, N, N′-di-t-butoxycarbonyl-1,9-diaminononane, N, N′-di- t-butoxycarbonyl-1,10-diaminodecane, N, N′-di-t-butoxycarbonyl-1,12-diaminododecane, N, N′-di-t-butoxy Nt- such as carbonyl-4,4′-diaminodiphenylmethane, Nt-butoxycarbonylbenzimidazole, Nt-butoxycarbonyl-2-methylbenzimidazole, Nt-butoxycarbonyl-2-phenylbenzimidazole, etc. Examples include a butoxycarbonyl group-containing amino compound.

Examples of the “quaternary ammonium hydroxide compound” include tetra-n-propylammonium hydroxide and tetra-n-butylammonium hydroxide.
Examples of the “nitrogen-containing heterocyclic compound” include: pyridine, 2-methylpyridine, 4-methylpyridine, 2-ethylpyridine, 4-ethylpyridine, 2-phenylpyridine, 4-phenylpyridine, 2-methyl-4 -Pyridines such as phenylpyridine, nicotine, nicotinic acid, nicotinamide, quinoline, 4-hydroxyquinoline, 8-oxyquinoline, acridine; piperazines such as piperazine, 1- (2-hydroxyethyl) piperazine, and pyrazines , Pyrazole, pyridazine, quinosaline, purine, pyrrolidine, piperidine, 3-piperidino-1,2-propanediol, morpholine, 4-methylmorpholine, 1,4-dimethylpiperazine, 1,4-diazabicyclo [2.2.2] Octane, imidazole, 4-methylimidazole 1-benzyl-2-methylimidazole, 4-methyl-2-phenylimidazole, benzimidazole, 2-phenylbenzimidazole, Nt-butoxycarbonylbenzimidazole, Nt-butoxycarbonyl-2-methylbenzimidazole, Examples thereof include Nt-butoxycarbonyl-2-phenylbenzimidazole.

The said nitrogen-containing compound (C) can be used individually or in mixture of 2 or more types.
In the present invention, the total amount of the nitrogen-containing compound (C) used is usually less than 10 parts by mass, preferably less than 5 parts by mass with respect to 100 parts by mass of the resin, from the viewpoint of ensuring high sensitivity as a resist. . In this case, when the total amount used exceeds 10 parts by mass, the sensitivity as a resist tends to be remarkably lowered. In addition, if the usage-amount of a nitrogen containing compound is less than 0.001 mass part, there exists a possibility that the pattern shape and dimension fidelity as a resist may fall depending on process conditions.

<Additives>
In the radiation sensitive resin composition of the present invention, various additives such as an acid diffusion controller, an alicyclic additive having an acid dissociable group, a surfactant, and a sensitizer are blended as necessary. be able to.
The alicyclic additive having an acid dissociable group is a component that exhibits an action of further improving dry etching resistance, pattern shape, adhesion to a substrate, and the like.
Examples of such alicyclic additives include 1-adamantanecarboxylic acid, 2-adamantanone, 1-adamantanecarboxylic acid t-butyl, 1-adamantanecarboxylic acid t-butoxycarbonylmethyl, 1-adamantanecarboxylic acid α. -Butyrolactone ester, 1,3-adamantane dicarboxylic acid di-t-butyl, 1-adamantane acetate t-butyl, 1-adamantane acetate t-butoxycarbonylmethyl, 1,3-adamantane diacetate di-t-butyl, 2, Adamantane derivatives such as 5-dimethyl-2,5-di (adamantylcarbonyloxy) hexane; t-butyl deoxycholic acid, t-butoxycarbonylmethyl deoxycholic acid, 2-ethoxyethyl deoxycholic acid, 2-deoxycholic acid 2- Cyclohexyloxyethyl, deoxy Deoxycholic acid esters such as 3-oxocyclohexyl cholic acid, tetrahydropyranyl deoxycholic acid, mevalonolactone ester of deoxycholic acid; t-butyl lithocholic acid, t-butoxycarbonylmethyl lithocholic acid, 2-ethoxyethyl lithocholic acid, Lithocholic acid esters such as lithocholic acid 2-cyclohexyloxyethyl, lithocholic acid 3-oxocyclohexyl, lithocholic acid tetrahydropyranyl, lithocholic acid mevalonolactone ester; dimethyl adipate, diethyl adipate, dipropyl adipate, din adipate -Alkyl carboxylic acid esters such as butyl and di-t-butyl adipate, and 3- [2-hydroxy-2,2-bis (trifluoromethyl) ethyl] tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodecane and the like. These alicyclic additives can be used alone or in admixture of two or more. The compounding amount of these alicyclic additives is usually 50 parts by mass or less, preferably 30 parts by mass or less with respect to 100 parts by mass of the resin (A). In this case, when the blending amount of the alicyclic additive exceeds 50 parts by mass, the heat resistance as a resist tends to decrease.

The surfactant is a component having an action of improving coating properties, striation, developability and the like.
Examples of such surfactants include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octylphenyl ether, polyoxyethylene n-nonylphenyl ether, and polyethylene glycol dilaurate. In addition to nonionic surfactants such as polyethylene glycol distearate, KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, no. 95 (manufactured by Kyoeisha Chemical Co., Ltd.), Ftop EF301, EF303, EF352 (manufactured by Tochem Products Co., Ltd.), Megafax F171, F173 (manufactured by Dainippon Ink & Chemicals, Inc.), Florard FC430, FC431 ( Sumitomo 3M Limited), Asahi Guard AG710, Surflon S-382, SC-101, SC-102, SC-103, SC-104, SC-105, SC-105, SC-106 (Asahi Glass Co., Ltd.) And the like. These surfactants can be used alone or in admixture of two or more. The compounding quantity of surfactant is 2 mass parts or less normally with respect to 100 mass parts of resin (A).

The sensitizer absorbs radiation energy and transmits the energy to the acid generator (B), thereby increasing the amount of acid produced. The radiation-sensitive resin composition It has the effect of improving the apparent sensitivity.
Examples of such sensitizers include carbazoles, acetophenones, benzophenones, naphthalenes, phenols, biacetyl, eosin, rose bengal, pyrenes, anthracenes, phenothiazines, and the like. These sensitizers can be used alone or in admixture of two or more. The blending amount of the sensitizer is preferably 50 parts by mass or less per 100 parts by mass of the resin (A).
In addition, by blending a dye or pigment, the latent image of the exposed area can be visualized, and the influence of halation during exposure can be alleviated. By blending an adhesion aid, adhesion to the substrate can be improved. it can. Furthermore, 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.

<Preparation of composition solution>
The radiation-sensitive resin composition of the present invention is usually dissolved in a solvent so that the total solid content concentration is usually 1 to 50% by mass, preferably 1 to 25% by mass. A composition solution is prepared by filtering with a filter having a pore diameter of about 200 nm.
Examples of the solvent (D) used for preparing the composition solution include 2-butanone, 2-pentanone, 3-methyl-2-butanone, 2-hexanone, 4-methyl-2-pentanone, 3-methyl- Linear or branched ketones such as 2-pentanone, 3,3-dimethyl-2-butanone, 2-heptanone, 2-octanone; cyclopentanone, 3-methylcyclopentanone, cyclohexanone, 2-methylcyclohexanone , Cyclic ketones such as 2,6-dimethylcyclohexanone and isophorone; propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol mono-n-propyl ether acetate, propylene glycol mono-i-propyl ether acetate, propylene G Propylene glycol monoalkyl ether acetates such as coal mono-n-butyl ether acetate, propylene glycol mono-i-butyl ether acetate, propylene glycol mono-sec-butyl ether acetate, propylene glycol mono-t-butyl ether acetate; methyl 2-hydroxypropionate , Ethyl 2-hydroxypropionate, n-propyl 2-hydroxypropionate, i-propyl 2-hydroxypropionate, n-butyl 2-hydroxypropionate, i-butyl 2-hydroxypropionate, 2-hydroxypropionic acid sec Alkyl 2-hydroxypropionates such as butyl and t-butyl 2-hydroxypropionate; methyl 3-methoxypropionate, 3-methoxypropionate Ethyl phosphate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate and the like of 3-alkoxy propionic acid alkyl ethers other,

  n-propyl alcohol, i-propyl alcohol, n-butyl alcohol, t-butyl alcohol, cyclohexanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-n-propyl ether, ethylene glycol mono-n-butyl ether , Diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol di-n-propyl ether, diethylene glycol di-n-butyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol mono-n-propyl ether acetate, propylene glycol monomethyl ether , Propylene glycol monoethyl Ether, propylene glycol mono-n-propyl ether, toluene, xylene, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutyrate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-methyl-3-methoxybutyl propionate, 3-methyl-3-methoxybutyl butyrate, ethyl acetate, n-propyl acetate, n-butyl acetate, methyl acetoacetate, Ethyl acetoacetate, methyl pyruvate, ethyl pyruvate, N-methylpyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, benzyl ethyl ether, di-n-hexyl ether, diethylene glycol monomethyl ether, diethylene glycol Cole monoethyl ether, caproic acid, caprylic acid, 1-octanol, 1-nonanol, benzyl alcohol, benzyl acetate, ethyl benzoate, diethyl oxalate, diethyl maleate, γ-butyrolactone, ethylene carbonate, propylene carbonate, etc. Can do.

Among these, linear or branched ketones, cyclic ketones, propylene glycol monoalkyl ether acetates, alkyl 2-hydroxypropionate, alkyl 3-alkoxypropionate, γ-butyrolactone and the like are preferable. .
These solvents can be used alone or in admixture of two or more.

<Method for forming resist pattern>
The radiation sensitive resin composition of the present invention is particularly useful as a chemically amplified resist. In the chemically amplified resist, the acid-dissociable group in the resin (A) is dissociated by the action of the acid generated from the acid generator by exposure to generate a carboxyl group, and as a result, alkali development of the exposed portion of the resist is performed. The solubility in the solution is increased, and the exposed portion is dissolved and removed by the alkali developer, and a positive resist pattern is obtained. When forming a resist pattern from the radiation-sensitive resin composition of the present invention, the composition solution is coated with, for example, a silicon wafer or aluminum by an appropriate application means such as spin coating, cast coating or roll coating. A resist film is formed by coating on a substrate such as a wafer, and in some cases, a heat treatment (hereinafter referred to as “PB”) is performed in advance, and then a predetermined resist pattern is formed on the resist film. Exposure. The radiation used at that time is appropriately selected from visible rays, ultraviolet rays, far ultraviolet rays, X-rays, charged particle beams, etc., depending on the type of acid generator to be used. ArF excimer laser Far ultraviolet rays represented by (wavelength 193 nm) or KrF excimer laser (wavelength 248 nm) are preferable, and ArF excimer laser (wavelength 193 nm) is particularly preferable. The exposure conditions such as the exposure amount are appropriately selected according to the composition of the radiation-sensitive resin composition, the type of additive, the immersion medium during the immersion exposure, and the like. In the present invention, it is preferable to perform heat treatment (PEB) after exposure. By this PEB, the dissociation reaction of the acid dissociable group in the resin (A) proceeds smoothly. The heating condition of PEB varies depending on the composition of the radiation sensitive resin composition, but is usually 30 to 200 ° C, preferably 50 to 170 ° C.

In the present invention, in order to maximize the potential of the radiation-sensitive resin composition, for example, as disclosed in Japanese Patent Publication No. 6-12458, an organic or inorganic substrate is used. An antireflection film can also be formed, and in order to prevent the influence of basic impurities contained in the environmental atmosphere, as disclosed in, for example, JP-A-5-188598, A protective film can be provided on the substrate, or these techniques can be used in combination.
Next, the exposed resist film is developed to form a predetermined resist pattern. Examples of the developer used for development include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, and di-n-propylamine. , Triethylamine, methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide, pyrrole, piperidine, choline, 1,8-diazabicyclo- [5.4.0] -7-undecene, 1,5-diazabicyclo- An alkaline aqueous solution in which at least one of alkaline compounds such as [4.3.0] -5-nonene is dissolved is preferable. The concentration of the alkaline aqueous solution is usually 10% by mass or less. In this case, if the concentration of the alkaline aqueous solution exceeds 10% by mass, the unexposed area may be dissolved in the developer, which is not preferable.

  Further, for example, an organic solvent can be added to the developer composed of the alkaline aqueous solution. Examples of organic solvents include ketones such as acetone, methyl ethyl ketone, methyl i-butyl ketone, cyclopentanone, cyclohexanone, 3-methylcyclopentanone, and 2,6-dimethylcyclohexanone; methyl alcohol, ethyl alcohol, n-propyl alcohol Alcohols such as i-propyl alcohol, n-butyl alcohol, t-butyl alcohol, cyclopentanol, cyclohexanol, 1,4-hexanediol and 1,4-hexanedimethylol; ethers such as tetrahydrofuran and dioxane; Examples thereof include esters such as ethyl acetate, n-butyl acetate and i-amyl acetate; aromatic hydrocarbons such as toluene and xylene; phenol, acetonylacetone and dimethylformamide. These organic solvents can be used alone or in admixture of two or more. The amount of the organic solvent used is preferably 100% by volume or less with respect to the alkaline aqueous solution. In this case, if the amount of the organic solvent used exceeds 100% by volume, the developability is lowered, and there is a possibility that the remaining development in the exposed area increases. In addition, an appropriate amount of a surfactant or the like can be added to the developer composed of an alkaline aqueous solution. In addition, after developing with the developing solution which consists of alkaline aqueous solution, generally it wash | cleans with water and dries.

The photoresist pattern formation method using the radiation sensitive resin composition of this invention is demonstrated.
In the step of forming a photoresist film by applying a photoresist on the substrate, for example, a silicon wafer, a wafer coated with aluminum, or the like can be used as the substrate. In order to maximize the potential of the resist film, an organic or inorganic antireflection film is formed on the substrate to be used, as disclosed in, for example, Japanese Patent Publication No. 6-12452. I can leave.
The photoresist used is not particularly limited, and can be selected in a timely manner according to the purpose of use of the resist. Examples of the resist include a chemically amplified positive type or negative type resist containing an acid generator.
When using the upper layer film for immersion formed with the composition of the present invention, a positive resist is particularly preferable. In a chemically amplified positive resist, an acid-dissociable organic group in the polymer is dissociated by the action of an acid generated from an acid generator by exposure to generate, for example, a carboxyl group. The solubility in an alkali developer is increased, and the exposed portion is dissolved and removed by the alkali developer to obtain a positive resist pattern.
For the photoresist film, the resin for forming the photoresist film is dissolved in a suitable solvent at a solid content concentration of, for example, 0.1 to 20% by mass, and then filtered through a filter having a pore diameter of, for example, about 30 nm. The resist solution is prepared by applying it onto a substrate by an appropriate application method such as spin coating, cast coating, roll coating, etc., and pre-baking (hereinafter referred to as “PB”) to volatilize the solvent. To do. In this case, a commercially available resist solution can be used as it is.
Moreover, the density | concentration of resin in the upper film | membrane formation composition for immersion is 0.1-20 mass% normally, Preferably it is 0.1-10 mass%, Most preferably, it is 0.1-5 mass%.

The step of forming an upper layer film on the photoresist film using the liquid immersion upper layer film-forming composition is performed by applying the upper layer film-forming composition of the present invention on the photoresist film and usually firing again. This is a step of forming an upper layer film of the present invention. This step is a step of forming an upper layer film for the purpose of protecting the photoresist film and preventing contamination of the lens of the projection exposure apparatus caused by elution of components contained in the resist from the photoresist film to the liquid. is there.
As the thickness of the upper layer film is closer to an odd multiple of λ / 4m (λ is the wavelength of radiation and m is the refractive index of the upper layer film), the reflection suppressing effect at the upper interface of the resist film is increased. For this reason, it is preferable that the thickness of the upper layer film be close to this value. In the present invention, any of the pre-baking after applying the resist solution and the baking after applying the upper layer film-forming composition solution may be omitted for simplification of the process.

The step of forming a resist pattern by irradiating the photoresist film and the upper film with radiation through a mask having a predetermined pattern using an immersion medium, for example, water, and then developing is performed by immersion exposure. This is a step of developing after baking at a predetermined temperature.
The pH of water filled between the photoresist film and the upper film can be adjusted. In particular, pure water is preferred.
The radiation used for immersion exposure depends on the photoresist film used and the combination of the photoresist film and the upper layer film for immersion, for example, visible rays; ultraviolet rays such as g rays and i rays; Various types of radiation such as ultraviolet rays; X-rays such as synchrotron radiation; and charged particle beams such as electron beams can be selectively used. In particular, an ArF excimer laser (wavelength 193 nm) or a KrF excimer laser (wavelength 248 nm) is preferable.
In order to improve the resolution, pattern shape, developability, etc. of the resist film, it is preferable to perform baking (hereinafter referred to as “PEB”) after exposure. The baking temperature is appropriately adjusted depending on the resist used and the like, but is usually about 30 to 200 ° C., preferably 50 to 150 ° C.
Next, the photoresist film is developed with a developer and washed to form a desired resist pattern. In this case, the upper film for immersion according to the present invention does not need to be subjected to a separate peeling step, and is completely removed during development or washing after development. This is one of the important features of the present invention.

  Examples of the developer used for forming the resist pattern in the present invention include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia, ethylamine, n-propylamine, diethylamine, and di-n-. Propylamine, triethylamine, methyldiethylamine, dimethylethanolamine, triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, pyrrole, piperidine, choline, 1,8-diazabicyclo- [5,4,0] -7-undecene An alkaline aqueous solution in which 1,5-diazabicyclo- [4,3,0] -5-nonane and the like are dissolved can be used. In addition, an appropriate amount of a water-soluble organic solvent, for example, alcohols such as methanol and ethanol, and a surfactant can be added to these developers. In the case where development is performed using the alkaline aqueous solution, it is usually washed with water after development.

Resin Synthesis Example A resin (A-1) that can form a stable film in an immersion medium at the time of radiation irradiation, such as water, and is dissolved in the developer after forming the resist pattern was synthesized by the following method. The Mw of the resin (A-1) is GPC column (2 G2000HXL, 1 G3000HXL, 1 G4000HXL) manufactured by Tosoh Corporation, flow rate 1.0 ml / min, elution solvent tetrahydrofuran, column temperature 40 ° C. The measurement was performed by gel permeation chromatography (GPC) using monodisperse polystyrene as a standard.

上記化合物（Ｍ−１）５３．９３ｇ（５０モル％）、化合物（Ｍ−２）３５．３８ｇ（４０モル％）、化合物（Ｍ−３）１０．６９ｇ（１０モル％）を２−ブタノン２００ｇに溶解し、さらにジメチル２，２'−アゾビス（２−メチルプロピオネート）５．５８ｇを投入した単量体溶液を準備し、１００ｇの２−ブタノンを投入した５００ｍｌの三口フラスコを３０分窒素パージした。窒素パージの後、反応釜を攪拌しながら８０℃に加熱し、事前に準備した上記単量体溶液を滴下漏斗を用いて３時間かけて滴下した。滴下開始を重合開始時間とし、重合反応を６時間実施した。重合終了後、重合溶液は水冷することにより３０℃以下に冷却し、２０００ｇのメタノールへ投入し、析出した白色粉末をろ別した。ろ別された白色粉末を２度４００ｇのメタノールにてスラリー上で洗浄した後、ろ別し、５０℃にて１７時間乾燥し、白色粉末の重合体を得た（７４ｇ、収率７４％）。この重合体はＭｗが６９００、Ｍｗ／Ｍｎ＝１．７０、¹³Ｃ-ＮＭＲ分析の結果、化合物（Ｍ−１）、化合物（Ｍ−２）、化合物（Ｍ−３）に由来する各繰り返し単位の含有率が５３．０：３７．２：９．８（モル％）の共重合体であった。この重合体をアクリル系重合体（Ａ−１）とする。なお、この重合体中の各単量体由来の低分子量成分の含有量は、この重合体１００質量％に対して、０．０３質量％であった。 Resin (A-1)

The above compound (M-1) 53.93 g (50 mol%), the compound (M-2) 35.38 g (40 mol%), the compound (M-3) 10.69 g (10 mol%) were converted into 200 g of 2-butanone. And a monomer solution charged with 5.58 g of dimethyl 2,2′-azobis (2-methylpropionate) was prepared, and a 500 ml three-necked flask charged with 100 g of 2-butanone was charged with nitrogen for 30 minutes. Purged. After purging with nitrogen, the reaction kettle was heated to 80 ° C. with stirring, and the monomer solution prepared in advance was added dropwise using a dropping funnel over 3 hours. The polymerization start was carried out for 6 hours with the start of dropping as the polymerization start time. After completion of the polymerization, the polymerization solution was cooled with water to 30 ° C. or lower, poured into 2000 g of methanol, and the precipitated white powder was separated by filtration. The filtered white powder was washed twice with 400 g of methanol on the slurry, filtered, and dried at 50 ° C. for 17 hours to obtain a white powder polymer (74 g, yield 74%). . As for this polymer, Mw is 6900, Mw / Mn = 1.70, ¹³ C-NMR analysis shows that each repeating unit derived from the compound (M-1), the compound (M-2), and the compound (M-3) Was a copolymer having a content of 53.0: 37.2: 9.8 (mol%). This polymer is referred to as “acrylic polymer (A-1)”. In addition, content of the low molecular weight component derived from each monomer in this polymer was 0.03 mass% with respect to 100 mass% of this polymer.

Examples 1 to 5 and Comparative Example 1
A radiation sensitive resin composition comprising the components shown in Table 1 was prepared. Components other than the resin (A-1) are as follows, and “parts” in the table are based on mass unless otherwise specified.
<Acid generator (B)>
(B-1): B1-2
(B-2): B1-3
(B-3): B1-20
(B-4): B1-21
(B-5): B1-22
(B-6): Triphenylsulfonium nonafluoro-n-butanesulfonate <nitrogen-containing compound (C)>
(C-1): Nt-butoxycarbonylpyrrolidine <solvent (D)>
(D-1): Propylene glycol monomethyl ether acetate (D-2): Cyclohexanone

<Evaluation of radiation-sensitive resin composition>
Various evaluations were performed on each Example and Comparative Example Table 1. The evaluation results are shown in Table 1.
The evaluation method is shown below.
(1) Elution amount (elution amount of acid generator and elution amount of acid diffusion control agent):
The figure explaining the elution amount measuring method is shown in FIG.
At the center of the 8-inch silicon wafer 1 having the processing layer 1a that has been subjected to HMDS (hexamethyldisilazane) treatment (100 ° C., 60 seconds) in advance by CLEAN TRACK ACT8 (manufactured by Tokyo Electron Ltd.), the center is Silicone rubber sheet 2 (manufactured by Kureha Elastomer Co., Ltd., thickness: 1.0 mm, shape: square with a side of 30 cm) was placed on a circular shape having a diameter (D1) of 11.3 cm. Next, 10 ml of ultrapure water 3 was filled in the hollowed portion at the center of the silicone rubber sheet 2 using a 10 ml hole pipette.
Thereafter, a lower antireflection film 4a having a film thickness of 77 nm (“ARC29A”, manufactured by Brewer Science Co., Ltd.) was previously formed on the silicone rubber sheet by CLEAN TRACK ACT8, and then the resist composition shown in Table 1 was subjected to the CLEAN. In TRACK ACT8, an 8-inch silicon wafer 4 (diameter D2) on which the resist coating 5 having a thickness of 205 nm was formed by spin coating on the lower antireflection film and baking (115 ° C., 60 seconds) was applied to the resist coating. The membrane surface was placed in contact with the ultrapure water and placed so that the ultrapure water did not leak from the silicone rubber.
And it kept for 10 seconds with the state. Thereafter, the 8-inch silicon wafer was removed, and ultrapure water was collected with a glass syringe, which was used as a sample for analysis. Note that the recovery rate of ultrapure water after the experiment was 95% or more.
Next, the peak intensity of the anion part of the photoacid generator in the ultrapure water obtained above was calculated using LC-MS (liquid chromatograph mass spectrometer, LC part: SERIES1100 manufactured by AGILENT, MS part: Perseptive Biosystems, Inc. (Manufactured by Mariner) was measured under the following measurement conditions. At that time, each peak intensity of 1 ppb, 10 ppb, and 100 ppb aqueous solutions of triphenylsulfonium nonafluoro-n-butanesulfonate was measured under the above measurement conditions to prepare a calibration curve, and the elution amount from the above peak intensity using this calibration curve. Was calculated. Similarly, each of the peak intensities of the 1 ppb, 10 ppb, and 100 ppb aqueous solutions of the acid diffusion control agent is measured under the above measurement conditions to create a calibration curve. Using this calibration curve, the acid diffusion control agent The amount of elution was calculated. When the elution amount was 5.0 × 10 ⁻¹² mol / cm ² / sec or more, it was judged as bad.

(Column condition)
Column used: “CAPCELL PAK MG”, manufactured by Shiseido Co., Ltd., 1 flow rate: 0.2 ml / min Outflow solvent: water / methanol (3/7) with 0.1% by mass of formic acid Measurement temperature: 35 ℃

(2) Sensitivity:
As the substrate, a 12-inch silicon wafer having a 77 nm-thick lower layer antireflection film (“ARC29A”, manufactured by Brewer Science) on the surface was used. For the formation of this antireflection film, “CLEAN TRACK ACT8” (manufactured by Tokyo Electron Limited) was used.
Subsequently, the resist composition of Table 1 was spin-coated on the said board | substrate by said CLEAN TRACK ACT8, and PB was performed at 120 degreeC for 60 second, and the resist film with a film thickness of 150 nm was formed. This resist film was exposed through a mask pattern by an ArF excimer laser exposure apparatus (“NSR S306C”, manufactured by ASML, certification condition: NA 0.78 sigma 0.93 / 0.69). Thereafter, PEB was performed at 115 ° C. for 60 seconds, and then developed with a 2.38 mass% tetramethylammonium hydroxide aqueous solution at 23 ° C. for 30 seconds, washed with water, and dried to form a positive resist pattern. . At this time, an exposure amount for forming a line-and-space pattern (1L1S) having a line width of 90 nm in a one-to-one line width was defined as an optimum exposure amount, and this optimum exposure amount was defined as sensitivity. A scanning electron microscope (“S-9380”, manufactured by Hitachi High-Technologies Corporation) was used for this length measurement.
(3) Cross-sectional shape of pattern:
When the cross-sectional shape of the 90 nm line and space pattern was observed with “S-4800” manufactured by Hitachi High-Technologies Corporation, and indicated a T-top shape, “x”, when a rectangular shape was obtained “○”.

表１から明らかなように、本発明の液浸露光用感放射線性樹脂組成物を用いた場合には、得られるパターン形状が良好であり、液浸露光時に接触した水への溶出物の量が少ないことが分かった。

As is apparent from Table 1, when the radiation-sensitive resin composition for immersion exposure of the present invention is used, the pattern shape obtained is good, and the amount of eluate in water contacted during immersion exposure It turns out that there are few.

  Since the radiation-sensitive resin composition for immersion exposure of the present invention uses at least one radiation-sensitive acid generator represented by formula (1) and formula (2), The amount of the eluate can be reduced, and it can be used very suitably for the manufacture of semiconductor devices that are expected to be further miniaturized in the future.

It is a figure explaining the elution amount measuring method.

Explanation of symbols

1 Silicon wafer 2 Silicon rubber sheet 3 Ultrapure water 4 Silicon wafer 5 Resist coating

Claims (2)

Used in a resist pattern forming method including immersion exposure in which radiation is irradiated between a lens and a photoresist film through an immersion exposure liquid, including a resin (A) and a radiation-sensitive acid generator (B), A radiation sensitive resin composition for forming the photoresist film,
The radiation sensitive acid generator (B) is at least one radiation sensitive acid generator represented by the following formulas (1) and (2).

(In Formula (1) and Formula (2), R ¹ is a hydrogen atom, a fluorine atom, a hydroxyl group, a linear or branched alkyl group having 1 to 10 carbon atoms, or a linear or branched group having 1 to 10 carbon atoms. Represents a linear alkoxyl group or a linear or branched alkoxycarbonyl group having 2 to 11 carbon atoms, R ² represents a linear or branched alkyl group having 1 to 10 carbon atoms, or 1 to 10 carbon atoms. A linear or branched alkoxyl group, or a linear, branched or cyclic alkanesulfonyl group having 1 to 10 carbon atoms, X represents a divalent group having 2 to 10 carbon atoms, R ⁴ and R ⁵ are each independently a linear, branched or cyclic fluorinated alkyl group having 1 to 8 carbon atoms, or a fluorinated alkylene group having 2 to 8 carbon atoms to which each R ⁴ is bonded. It represents, or two R ⁵ are bonded carbon Represents 2-8 fluorinated alkylene group, n is an integer of 0 to 2, m is an integer of 0) Used in a resist pattern forming method including immersion exposure in which radiation is irradiated between a lens and a photoresist film through an immersion exposure liquid, including a resin (A) and a radiation-sensitive acid generator (B), A radiation sensitive resin composition for forming the photoresist film,
The radiation-sensitive acid generator (B) is at least one radiation-sensitive acid generator represented by the following formulas (3) and (4).

(In Formula (3) and Formula (4), R ¹ is a hydrogen atom, a fluorine atom, a hydroxyl group, a linear or branched alkyl group having 1 to 10 carbon atoms, or a linear or branched group having 1 to 10 carbon atoms. Represents a linear alkoxyl group or a linear or branched alkoxycarbonyl group having 2 to 11 carbon atoms, R ² represents a linear or branched alkyl group having 1 to 10 carbon atoms, or 1 to 10 carbon atoms. A linear or branched alkoxyl group or a linear, branched, or cyclic alkanesulfonyl group having 1 to 10 carbon atoms, and R ³ is independently a linear or branched group having 1 to 10 carbon atoms. And represents an optionally substituted phenyl group or naphthyl group, and R ^{4 ′} represents a linear, branched or cyclic fluorinated alkyl group having 1 to 8 carbon atoms, R 5 ^'is, charcoal independently of each other 1-8C straight-chain, branched or cyclic fluorinated alkyl group or represents two fluorinated alkylene group R ^{5 '2} to 8 carbon atoms which is bonded, n represents an integer of 0 to 2, And m is an integer from 0 to 10)

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