JP2010145516A - Positive resist composition and method for forming resist pattern - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positive resist composition which has high resolution and enables to form a resist pattern of good shape with small LWR, and a method for forming a resist pattern. <P>SOLUTION: The positive resist composition includes a base component (A) which exhibits increased solubility in an alkali developer under the action of an acid and an acid generator component (B) which generates an acid upon exposure, wherein the base component (A) includes a polymeric compound (A1) having a constitutional unit (a10) having a hydroxy group-containing naphthalene derivative group in a side chain, a constitutional unit (a11) having an acid dissociable group in a side chain, and a constitutional unit (a12) having an acid dissociable group-containing ester group in a side chain. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a positive resist composition and a resist pattern forming method.

In lithography technology, for example, a resist film made of a resist material is formed on a substrate, the resist film is selectively exposed with radiation such as light or an electron beam, and subjected to a development process, whereby the resist A step of forming a resist pattern having a predetermined shape on the film is performed. A resist material in which the exposed portion changes to a property that dissolves in the developer is referred to as a positive type, and a resist material that changes to a property in which the exposed portion does not dissolve in the developer is referred to as a negative type.
In recent years, in the manufacture of semiconductor elements and liquid crystal display elements, pattern miniaturization has been rapidly progressing due to advances in lithography technology.
As a technique for miniaturization, the wavelength of an exposure light source is generally shortened. Specifically, conventionally, ultraviolet rays typified by g-line and i-line have been used, but now mass production of semiconductor elements using a KrF excimer laser or an ArF excimer laser has started. In addition, studies have been made on F ₂ excimer lasers, electron beams, EUV (extreme ultraviolet rays), X-rays, and the like having shorter wavelengths than these excimer lasers.

Resist materials are required to have lithography characteristics such as sensitivity to these exposure light sources and resolution capable of reproducing a pattern with fine dimensions. As a resist material that satisfies such requirements, a chemically amplified resist containing a base resin whose solubility in an alkaline developer is changed by the action of an acid and an acid generator that generates an acid upon exposure is used. For example, a positive chemically amplified resist contains, as a base resin, a resin that increases solubility in an alkaline developer by the action of an acid and an acid generator. When the acid is generated, the exposed portion becomes soluble in the alkaline developer.
At present, as a chemically amplified positive resist, a resin in which a hydrophilic group is protected by a group (acid dissociable, dissolution inhibiting group) that is dissociated by the action of an acid generated from an acid generator is usually used. , A resin in which a part of hydroxyl groups of a polyhydroxystyrene resin is protected with an acid dissociable, dissolution inhibiting group, a copolymer of hydroxystyrene and a (meth) acrylic acid ester having an acid dissociable, dissolution inhibiting group (for example, a patent) Documents 1 and 2 and Non-Patent Document 1), acrylic resins having an acid dissociable, dissolution inhibiting group, and the like are known (for example, refer to Patent Document 3).
Here, “(meth) acrylic acid” means one or both of acrylic acid having a hydrogen atom bonded to the α-position and methacrylic acid having a methyl group bonded to the α-position. “(Meth) acrylic acid ester” means one or both of an acrylic acid ester having a hydrogen atom bonded to the α-position and a methacrylic acid ester having a methyl group bonded to the α-position. “(Meth) acrylate” means one or both of an acrylate having a hydrogen atom bonded to the α-position and a methacrylate having a methyl group bonded to the α-position.
JP-A-8-101509 JP 2000-267286 A JP 2003-241385 A "Journal of Photopolymer Science and Technology" Vol.13, No.3 (2000), p397-404

In the future, there are demands for new materials that can be used for lithography applications, as further progress in lithography technology and expansion of application fields are expected. For example, as the pattern becomes finer, the resist material is also required to have improved resolution. In addition, as the resolution is improved, other various lithography properties are also required to be improved. For example, when the rectangular shape of the cross-sectional shape of the resist pattern is low or the LWR (line width roughness) is large, the formation of fine semiconductor elements may be adversely affected. LWR is a phenomenon in which when a resist pattern is formed using a resist composition, the pattern surface is roughened (roughness) and the line width of the line pattern becomes non-uniform.
Therefore, the improvement of the resist pattern shape and LWR becomes more important as the pattern becomes finer. In particular, in lithography using an electron beam or EUV, since a fine pattern formation of several tens of nanometers is a target, improvement of the resist pattern shape and LWR is extremely important.
The present invention has been made in view of the above circumstances, and provides a positive resist composition and a resist pattern forming method capable of forming a resist pattern having a high resolution, a low LWR, and a good shape. Let it be an issue.

In order to solve the above problems, the present invention employs the following configuration.
That is, the first aspect of the present invention is a positive type containing a base component (A) whose solubility in an alkaline developer is increased by the action of an acid, and an acid generator component (B) that generates an acid upon exposure. A resist composition comprising:
The base component (A) is a structural unit (a10) represented by the following general formula (a10-1), a structural unit (a11) represented by the following general formula (a11-1), and the following general formula (a12). A positive resist composition comprising the polymer compound (A1) having the structural unit (a12) represented by -1).

［式中、Ｒ^１は水素原子または炭素数１〜５のアルキル基であり、Ｙ^１は単結合または−Ｃ（＝Ｏ）−Ｏ−Ｒ^２０−（Ｒ^２０は単結合または２価の連結基である。）であり、Ｒ^２は単結合またはアルキレン基であり、Ｒ^３はハロゲン原子、炭素数１〜５のアルキル基または炭素数１〜５のハロゲン化アルキル基であり、ｘは１〜３の整数であり、ｙは０〜６の整数であり、ｘ＋ｙは１〜７であり、Ｒは水素原子、炭素数１〜５のアルキル基または炭素数１〜５のハロゲン化アルキル基であり、Ｘ^１は酸解離性溶解抑制基であり、Ｙ^２は２価の連結基であり、Ｘ^２は酸解離性溶解抑制基である。］

[Wherein, R ¹ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, Y ¹ is a single bond or —C (═O) —O—R ²⁰ — (R ²⁰ is a single bond or a divalent linkage) R ² is a single bond or an alkylene group, R ³ is a halogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms, and x is 1 Is an integer of -3, y is an integer of 0-6, x + y is 1-7, R is a hydrogen atom, a C1-C5 alkyl group or a C1-C5 halogenated alkyl group. Yes, X ¹ is an acid dissociable, dissolution inhibiting group, Y ² is a divalent linking group, and X ² is an acid dissociable, dissolution inhibiting group. ]

  According to a second aspect of the present invention, there is provided a step of forming a resist film on a support using the positive resist composition of the first aspect, a step of exposing the resist film, and an alkali development of the resist film. And a resist pattern forming method including a step of forming a resist pattern.

In the present specification and claims, the “alkyl group” includes linear, branched and cyclic monovalent saturated hydrocarbon groups unless otherwise specified.
Unless otherwise specified, the “alkylene group” includes linear, branched and cyclic divalent saturated hydrocarbon groups.
The “halogenated alkyl group” is a group in which part or all of the hydrogen atoms of the alkyl group are substituted with a halogen atom, and examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
“Aliphatic” is a relative concept with respect to aromatics, and is defined to mean groups, compounds, and the like that do not have aromaticity.
The “structural unit” means a monomer unit (monomer unit) constituting a polymer compound (polymer, copolymer).
“Exposure” is a concept including general irradiation of radiation.

  According to the present invention, it is possible to provide a positive resist composition and a resist pattern forming method capable of forming a resist pattern having a high resolution, a small LWR, and a good shape.

≪Positive resist composition≫
The positive resist composition of the present invention (hereinafter sometimes referred to simply as “resist composition”) is a base component (A) (hereinafter referred to as “component (A)”) whose solubility in an alkaline developer is increased by the action of an acid. ), And an acid generator component (B) (hereinafter referred to as component (B)) that generates an acid upon irradiation with radiation.
In such a positive resist composition, when radiation is irradiated (exposed), an acid is generated from the component (B), and the solubility of the component (A) in an alkaline developer is increased by the action of the acid. Therefore, in the formation of a resist pattern, when selective exposure is performed on a resist film obtained using the positive resist composition, the solubility of the resist film in an alkaline developer in an exposed area increases. Since the solubility of the unexposed portion in the alkaline developer does not change, a resist pattern can be formed by performing alkali development.
Here, the “base material component” is an organic compound having a film forming ability. As the substrate component, an organic compound having a molecular weight of 500 or more is preferably used. When the molecular weight of the organic compound is 500 or more, the film-forming ability is improved and a nano-level resist pattern is easily formed.
“Organic compounds having a molecular weight of 500 or more” used as the base component are roughly classified into non-polymers and polymers.
As the non-polymer, those having a molecular weight of 500 or more and less than 4000 are usually used. Hereinafter, a nonpolymer having a molecular weight of 500 or more and less than 4000 is referred to as a low molecular compound.
As the polymer, those having a molecular weight of 2000 or more are usually used. Hereinafter, a polymer having a molecular weight of 2000 or more is referred to as a polymer compound. In the case of a polymer compound, the “molecular weight” is a polystyrene-reduced mass average molecular weight determined by GPC (gel permeation chromatography). Hereinafter, the polymer compound may be simply referred to as “resin”.

<(A) component>
[Polymer Compound (A1)]
The polymer compound (A1) (hereinafter referred to as the component (A1)) has structural units (a10) to (a12).

Structural unit (a10):
The structural unit (a10) is a structural unit represented by the following general formula (a10-1).

［式中、Ｒ^１は水素原子または炭素数１〜５のアルキル基であり、Ｙ^１は単結合または−Ｃ（＝Ｏ）−Ｏ−Ｒ^２０−（Ｒ^２０は単結合または２価の連結基である。）であり、Ｒ^２は単結合またはアルキレン基であり、Ｒ^３はハロゲン原子、炭素数１〜５のアルキル基または炭素数１〜５のハロゲン化アルキル基であり、ｘは１〜３の整数であり、ｙは０〜６の整数であり、ｘ＋ｙは１〜７である。］

[Wherein, R ¹ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, Y ¹ is a single bond or —C (═O) —O—R ²⁰ — (R ²⁰ is a single bond or a divalent linkage) R ² is a single bond or an alkylene group, R ³ is a halogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms, and x is 1 Is an integer of -3, y is an integer of 0-6, and x + y is 1-7. ]

In formula (a10-1), R ¹ represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.
The alkyl group for R ¹ is preferably an alkyl group having 1 to 5 carbon atoms. The alkyl group is preferably a linear or branched alkyl group, and specifically includes a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, and pentyl. Group, isopentyl group, neopentyl group and the like.

Y ¹ is a single bond or —C (═O) —O—R ²⁰ — (R ²⁰ is a single bond or a divalent linking group).
Preferred examples of the divalent linking group for R ²⁰ include a divalent hydrocarbon group which may have a substituent, a divalent linking group containing a hetero atom, and the like.
In the “divalent hydrocarbon group optionally having substituent (s)” for R ^20, the hydrocarbon group has “substituent” means that part or all of the hydrogen atoms in the hydrocarbon group are It means substituted with a group or atom other than a hydrogen atom.
The hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. An aliphatic hydrocarbon group means a hydrocarbon group having no aromaticity.
The aliphatic hydrocarbon group may be saturated or unsaturated, and is usually preferably saturated.
More specifically, examples of the aliphatic hydrocarbon group include a linear or branched aliphatic hydrocarbon group, an aliphatic hydrocarbon group containing a ring in the structure, and the like.

The linear or branched aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 8, more preferably 1 to 5, and most preferably 1 to 2.
As the linear aliphatic hydrocarbon group, a linear alkylene group is preferable. Specifically, a methylene group [—CH ₂ —], an ethylene group [— (CH ₂ ) ₂ —], a trimethylene group [ — (CH ₂ ) ₃ —], tetramethylene group [— (CH ₂ ) ₄ —], pentamethylene group [— (CH ₂ ) ₅ —] and the like can be mentioned.
As the branched aliphatic hydrocarbon group, a branched alkylene group is preferred, and specifically, —CH (CH ₃ ) —, —CH (CH ₂ CH ₃ ) —, —C (CH ₃ ). Alkylmethylene groups such as _2- , —C (CH ₃ ) (CH ₂ CH ₃ ) —, —C (CH ₃ ) (CH ₂ CH ₂ CH ₃ ) —, —C (CH ₂ CH ₃ ) ₂ —; _{CH (CH 3) CH 2 -} , - CH (CH 3) CH (CH 3) -, - C (CH 3) 2 CH 2 -, - CH (CH 2 CH 3) CH 2 -, - C (CH 2 CH _{3) 2} -CH ₂ - alkyl groups such _{as; -CH (CH 3) CH 2} CH 2 -, - CH 2 CH (CH 3) CH 2 - alkyl trimethylene groups such as; -CH _(CH 3) _{CH 2 CH 2 CH 2 -,} - CH 2 CH (CH 3) CH 2 CH 2 - And the like alkyl alkylene group such as an alkyl tetramethylene group of. The alkyl group in the alkyl alkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.
The chain-like aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, and an oxygen atom (= O).

Examples of the aliphatic hydrocarbon group containing a ring in the structure include a cyclic aliphatic hydrocarbon group (a group obtained by removing two hydrogen atoms from an aliphatic hydrocarbon ring), and the cyclic aliphatic hydrocarbon group described above. Examples thereof include a group bonded to the terminal of a chain aliphatic hydrocarbon group or interposed in the middle of a chain aliphatic hydrocarbon group.
The cyclic aliphatic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably 3 to 12 carbon atoms.
The cyclic aliphatic hydrocarbon group may be a polycyclic group or a monocyclic group. As the monocyclic group, a group in which two hydrogen atoms have been removed from a monocycloalkane having 3 to 6 carbon atoms is preferable, and examples of the monocycloalkane include cyclopentane and cyclohexane.
As the polycyclic group, a group in which two hydrogen atoms are removed from a polycycloalkane having 7 to 12 carbon atoms is preferable. Specific examples of the polycycloalkane include adamantane, norbornane, isobornane, tricyclodecane, tetra And cyclododecane.
The cyclic aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, and an oxygen atom (= O).

Examples of the aromatic hydrocarbon group include aromatics of monovalent aromatic hydrocarbon groups such as a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, an anthryl group, and a phenanthryl group. A divalent aromatic hydrocarbon group obtained by removing one hydrogen atom from the nucleus of the aromatic hydrocarbon;
An aromatic hydrocarbon group in which a part of carbon atoms constituting the ring of the divalent aromatic hydrocarbon group is substituted with a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom;
A benzyl group, a phenethyl group, a 1-naphthylmethyl group, a 2-naphthylmethyl group, an 1-naphthylethyl group, an arylalkyl group such as a 2-naphthylethyl group, etc., and a hydrogen atom from the nucleus of the aromatic hydrocarbon Further, an aromatic hydrocarbon group or the like from which one is removed can be mentioned.
The aromatic hydrocarbon group may or may not have a substituent. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, and an oxygen atom (= O).

In the “divalent linking group containing a heteroatom” in R ^20, the heteroatom in the “divalent linking group containing a heteroatom” is an atom other than a carbon atom and a hydrogen atom, such as an oxygen atom, a nitrogen atom, A sulfur atom, a halogen atom, etc. are mentioned.
Specific examples of the divalent linking group containing a hetero atom include —O—, —C (═O) —, —C (═O) —O—, and a carbonate bond (—O—C (═O) —. O—), —NH—, —NR ⁰⁴ (R ⁰⁴ is an alkyl group) —, —NH—C (═O) —, ═N— and the like. Moreover, the combination etc. of these "divalent coupling groups containing a hetero atom" and a bivalent hydrocarbon group are mentioned. Examples of the divalent hydrocarbon group include the same hydrocarbon groups that may have a substituent as described above, and a linear or branched aliphatic hydrocarbon group is preferable.

The divalent linking group for R ²⁰ is preferably an alkylene group, an ester bond (—C (═O) —O—), or a combination thereof.
The alkylene group for R ²⁰ is more preferably a linear or branched alkylene group. Specifically, the same as the linear alkylene group and branched alkylene group mentioned as the aliphatic hydrocarbon group for R ²⁰ can be used.
The linear alkylene group for R ²⁰ is preferably a methylene group or an ethylene group, and particularly preferably a methylene group.
The branched alkylene group for R ²⁰ is preferably an alkylmethylene group or an alkylethylene group, and —CH (CH ₃ ) —, —C (CH ₃ ) ₂ — or —C (CH ₃ ) ₂ CH ₂ — is Particularly preferred.
Examples of the combination of an alkylene group and an ester bond (-C (= O) -O-) , ^{e.g., -R 20 '-C (= O} ) -O -, - R 20' -C (= O) -O- R ²⁰ ″ — and the like. In the formula, R ²⁰ ′ and R ²⁰ ″ are each independently an alkylene group. As the alkylene group for R ²⁰ ′ and R ²⁰ ″, the same alkylene groups as those described above for R ²⁰ can be used.

R ²⁰ may be a single bond or a divalent linking group. A single bond or an alkylene group is preferred, and a single bond is most preferred.

In the present invention, Y ¹ is a single bond, —C (═O) —O— or —C (═O) —O—R ²⁰ ′ — (R ²⁰ ′ is the same as described above). Preferably, a single bond or —C (═O) —O— is more preferable, and a single bond is most preferable.

R ² is a single bond or an alkylene group.
The alkylene group for R ² may be linear, branched or cyclic, and is preferably linear or branched. The alkylene group preferably has 1 to 12 carbon atoms, and specific examples thereof include a group in which one hydrogen atom has been removed from the alkyl group described above for R ¹ .
R ² is preferably a single bond or a methylene group, and most preferably a single bond.
When x is an integer of 2 or more, the plurality of R ² may be the same or different from each other. For example, if x is 2, the two ^-R 2 -OH, in which one ^{R 2} is a hydrogen atom, the other of ^{R 2} may be an alkylene group.

R ³ is a halogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms.
Examples of the halogen atom for R ³ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable.
The alkyl group of R ^3, the same as the alkyl group of R ^1.
Examples of the halogenated alkyl group for R ^3, part or all of the hydrogen atoms in the alkyl group described as the above-described alkyl group R ³ can be cited group substituted by a halogen atom. Examples of the halogen atom include the same as those mentioned as the halogen atom for R ³ . The halogenated alkyl group for R ³ is preferably a fluorinated alkyl group.
If y is an integer of 2 or more, plural R ³ may be each the same or different.

x is an integer of 1 to 3, and y is an integer of 0 to 6. However, x + y is 1-7.
x is most preferably 1.
y is preferably an integer of 0 to 2, preferably 0 or 1, and particularly preferably 0.

In formula (a10-1), Y ¹ (the carbon atom to which R ¹ is bonded when Y ¹ is a single bond) may be bonded to the 1-position of the naphthalene ring or bonded to the 2-position. May be.
The bonding position of —R ² —OH in the naphthalene ring is not particularly limited. When Y ¹ (the carbon atom to which R ¹ is bonded when Y ¹ is a single bond) is bonded to the 1-position or 2-position of the naphthalene ring, any one of 5 to 8 positions of the naphthalene ring is preferable. In particular, when x is 1, any one of 5 to 7 positions of the naphthalene ring is preferable, and 5 or 6 positions are preferable. When x is an integer greater than or equal to 2, arbitrary bond positions can be combined.

  As the structural unit (a10), structural units represented by general formulas (a10-11) to (a10-16) shown below are particularly preferable.

［式中、Ｒ^１およびＹ^１はそれぞれ前記と同じである。］

[Wherein, R ¹ and Y ¹ are the same as defined above. ]

In the component (A1), as the structural unit (a10), one type may be used alone, or two or more types may be used in combination.
The proportion of the structural unit (a10) in the component (A1) is preferably 50 to 85 mol%, more preferably 55 to 80 mol%, based on the total of all the structural units constituting the component (A). 60 to 75 mol% is most preferable. Within this range, moderate alkali solubility is obtained when a resist composition is obtained. In addition, lithography properties such as resolution and sensitivity are improved.

Structural unit (a11):
The structural unit (a11) is represented by the following general formula (a11-1).

［式中、Ｒは水素原子、炭素数１〜５のアルキル基または炭素数１〜５のハロゲン化アルキル基であり、Ｘ^１は酸解離性溶解抑制基である。］

[Wherein, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms, and X ¹ is an acid dissociable, dissolution inhibiting group. ]

In formula (a11-1), R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms.
The alkyl group of R is preferably a linear or branched alkyl group, specifically, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, pentyl group. Group, isopentyl group, neopentyl group and the like.
Examples of the halogenated alkyl group for R include groups in which part or all of the hydrogen atoms of the alkyl group have been substituted with halogen atoms. Examples of the halogen atom in the halogenated alkyl group include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and a fluorine atom is particularly preferable.
R is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a fluorinated alkyl group having 1 to 5 carbon atoms, and is most preferably a hydrogen atom or a methyl group in terms of industrial availability.

X ¹ is an acid dissociable, dissolution inhibiting group. The “acid dissociable, dissolution inhibiting group” has an alkali dissolution inhibiting property that makes the entire component (A1) difficult to dissolve in an alkali developer before dissociation, and also by the action of an acid generated from the component (B) by exposure. The dissociation increases the solubility of the entire component (A1) in an alkaline developer.
As the acid dissociable, dissolution inhibiting group, those proposed so far as the acid dissociable, dissolution inhibiting group of the base resin for chemically amplified resist can be used. In general, a group that forms a cyclic or chain tertiary alkyl ester with a carboxy group in (meth) acrylic acid or the like; an acetal-type acid dissociable, dissolution inhibiting group such as an alkoxyalkyl group is widely known. . The “(meth) acrylic acid ester” means one or both of an acrylic acid ester having a hydrogen atom bonded to the α-position and a methacrylic acid ester having a methyl group bonded to the α-position.
Here, the “tertiary alkyl ester” is an ester formed by replacing a hydrogen atom of a carboxy group with a chain or cyclic alkyl group, and the carbonyloxy group (—C (O)). A structure in which the tertiary carbon atom of the chain or cyclic alkyl group is bonded to the terminal oxygen atom of -O-). In this tertiary alkyl ester, when an acid acts, a bond is cut between an oxygen atom and a tertiary carbon atom.
The chain or cyclic alkyl group may have a substituent.
Hereinafter, a group that is acid dissociable by constituting a carboxy group and a tertiary alkyl ester is referred to as a “tertiary alkyl ester type acid dissociable, dissolution inhibiting group” for convenience.

Examples of the tertiary alkyl ester type acid dissociable, dissolution inhibiting group include an aliphatic branched acid dissociable, dissolution inhibiting group and an acid dissociable, dissolution inhibiting group containing an aliphatic cyclic group.
Here, “aliphatic branched” means having a branched structure without aromaticity. The structure of the “aliphatic branched acid dissociable, dissolution inhibiting group” is not limited to a group consisting of carbon and hydrogen (hydrocarbon group), but is preferably a hydrocarbon group. The “hydrocarbon group” may be either saturated or unsaturated, but is usually preferably saturated.
Examples of the aliphatic branched acid dissociable, dissolution inhibiting group include a group represented by -C (R ⁷¹ ) (R ⁷² ) (R ⁷³ ). ^Wherein, R 71 ^{to R 73} each independently represents a linear alkyl group of 1 to 5 carbon atoms. The group represented by —C (R ⁷¹ ) (R ⁷² ) (R ⁷³ ) preferably has 4 to 8 carbon atoms, specifically, a tert-butyl group or a 2-methyl-2-butyl group. 2-methyl-2-pentyl group, 3-methyl-3-pentyl group, and the like. A tert-butyl group is particularly preferable.

The “aliphatic cyclic group” means a monocyclic group or a polycyclic group having no aromaticity. In the present invention, the aliphatic cyclic group is preferably a polycyclic group.
The aliphatic cyclic group may or may not have a substituent. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, and an oxygen atom (= O). , Etc.
The basic ring structure excluding the substituent of the “aliphatic cyclic group” is not limited to a ring composed of carbon and hydrogen (hydrocarbon ring), but is preferably a hydrocarbon ring. Further, a part of carbon atoms constituting the ring skeleton of the hydrocarbon ring may be substituted with an etheric oxygen atom (—O—). The hydrocarbon ring may be either saturated or unsaturated, but is usually preferably saturated.
Specific examples of the hydrocarbon ring include optionally substituted monocycloalkanes; polycycloalkanes such as bicycloalkanes, tricycloalkanes, and tetracycloalkanes.
More specifically, examples of the monocycloalkane include cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclononane, cyclodecane, and the like.
More specifically, examples of the polycycloalkane include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.
The aliphatic cyclic group may or may not have a substituent. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, and an oxygen atom (= O). , Etc.

Examples of the acid dissociable, dissolution inhibiting group containing an aliphatic cyclic group include:
(I) a group having a tertiary carbon atom on the ring skeleton of a monovalent aliphatic cyclic group;
(Ii) a group having a monovalent aliphatic cyclic group and a branched alkylene having a tertiary carbon atom bonded thereto, and the like.
Specific examples of the “(i) group having a tertiary carbon atom on the ring skeleton of a monovalent aliphatic cyclic group” include, for example, the following general formulas (1-1) to (1-9): And the group represented.
Specific examples of the “(ii) group having a monovalent aliphatic cyclic group and a branched alkylene group having a tertiary carbon atom bonded thereto” include, for example, the following general formula (2- Examples include groups represented by 1) to (2-6).

［式中、Ｒ^１４はアルキル基であり、ｇは０〜８の整数である。］

^{Wherein, R 14} represents an alkyl group, g is an integer of 0-8. ]

［式中、Ｒ^１５およびＲ^１６は、それぞれ独立してアルキル基である。］

[Wherein, R ¹⁵ and R ¹⁶ each independently represents an alkyl group. ]

The alkyl group for R ¹⁴ may be linear, branched or cyclic.
The linear alkyl group preferably has 1 to 5 carbon atoms, and more preferably 2 to 4 carbon atoms. Specific examples include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, and an n-pentyl group. Among these, a methyl group, an ethyl group or an n-butyl group is preferable, and an ethyl group is most preferable.
The branched alkyl group preferably has 3 to 10 carbon atoms, and more preferably 3 to 5 carbon atoms. Specific examples include isopropyl group, isobutyl group, tert-butyl group, isopentyl group, neopentyl group and the like. Of these, isopropyl is most preferred.
The cyclic alkyl group preferably has 3 to 10 carbon atoms, and more preferably 5 or 6. Specific examples include a cyclopentyl group and a cyclohexyl group.
R ¹⁴ is preferably a linear or branched alkyl group, more preferably a methyl group, an ethyl group, an isopropyl group or an n-butyl group, and more preferably a methyl group, an ethyl group or an isopropyl group.
g is preferably an integer of 0 to 3, more preferably an integer of 1 to 3, and still more preferably 1 or 2.

Examples of the alkyl group for R ^{15 to} R ¹⁶ include the same alkyl groups as those for R ¹⁴ .
In the above formulas (1-1) to (1-9) and (2-1) to (2-6), some of the carbon atoms constituting the ring are substituted with etheric oxygen atoms (—O—). May be.
In formulas (1-1) to (1-9) and (2-1) to (2-6), a hydrogen atom bonded to a carbon atom constituting the ring may be substituted with a substituent. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, a fluorine atom, and a fluorinated alkyl group.

The “acetal-type acid dissociable, dissolution inhibiting group” is generally bonded to an oxygen atom by substituting a hydrogen atom at the terminal of an alkali-soluble group such as a carboxy group or a hydroxyl group. When an acid is generated by exposure, the acid acts to break the bond between the acetal acid dissociable, dissolution inhibiting group and the oxygen atom to which the acetal acid dissociable, dissolution inhibiting group is bonded.
Examples of the acetal type acid dissociable, dissolution inhibiting group include a group represented by the following general formula (p1).

［式中、Ｒ^１’，Ｒ^２’はそれぞれ独立して水素原子または炭素数１〜５のアルキル基を表し、ｎは０〜３の整数を表し、Ｙは炭素数１〜５のアルキル基または脂肪族環式基を表す。］

[Wherein, R ¹ 'and R ² ' each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, n represents an integer of 0 to 3, and Y represents an alkyl group having 1 to 5 carbon atoms. Or represents an aliphatic cyclic group. ]

In the formula (p1), n is preferably an integer of 0 to 2, more preferably 0 or 1, and most preferably 0.
Examples of the alkyl group having 1 to 5 carbon atoms of R ¹ ′ and R ² ′ include the same alkyl groups as those described above for R. A methyl group or an ethyl group is preferable, and a methyl group is most preferable.
In the present invention, it is preferable that at least one of R ¹ ′ and R ² ′ is a hydrogen atom. That is, the acid dissociable, dissolution inhibiting group (p1) is preferably a group represented by the following general formula (p1-1).

［式中、Ｒ^１’、ｎ、Ｙは上記と同じである。］

[Wherein R ¹ ′, n and Y are the same as described above. ]

Examples of the alkyl group for Y include the same alkyl groups as those described above for R.
The aliphatic cyclic group for Y can be appropriately selected from monocyclic or polycyclic aliphatic cyclic groups conventionally proposed in a number of ArF resists and the like. For example, the above “aliphatic ring” Examples thereof are the same as those in the formula group.

  Examples of the acetal type acid dissociable, dissolution inhibiting group also include a group represented by the following general formula (p2).

［式中、Ｒ^１７、Ｒ^１８はそれぞれ独立して直鎖状若しくは分岐鎖状のアルキル基または水素原子であり；Ｒ^１９は直鎖状、分岐鎖状若しくは環状のアルキル基である。または、Ｒ^１７およびＲ^１９がそれぞれ独立に直鎖状若しくは分岐鎖状のアルキレン基であって、Ｒ^１７の末端とＲ^１９の末端とが結合して環を形成していてもよい。］

[Wherein, R ¹⁷ and R ¹⁸ each independently represents a linear or branched alkyl group or a hydrogen atom; and R ¹⁹ represents a linear, branched or cyclic alkyl group. Alternatively, R ¹⁷ and R ¹⁹ may be each independently a linear or branched alkylene group, and the end of R ^{17 and} the end of R ¹⁹ may be bonded to form a ring. ]

In R ¹⁷ and R ¹⁸ , the alkyl group preferably has 1 to 15 carbon atoms, may be linear or branched, and is preferably an ethyl group or a methyl group, and most preferably a methyl group.
In particular, it is preferable that one of R ¹⁷ and R ¹⁸ is a hydrogen atom and the other is a methyl group.
R ¹⁹ is a linear, branched or cyclic alkyl group, preferably having 1 to 15 carbon atoms, and may be any of linear, branched or cyclic.
When R ¹⁹ is linear or branched, it preferably has 1 to 5 carbon atoms, more preferably an ethyl group or a methyl group, and most preferably an ethyl group.
When R ¹⁹ is cyclic, it preferably has 4 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. Specifically, one or more polycycloalkanes such as monocycloalkane, bicycloalkane, tricycloalkane, tetracycloalkane, which may or may not be substituted with a fluorine atom or a fluorinated alkyl group. And the like, in which a hydrogen atom is removed. Specific examples include monocycloalkanes such as cyclopentane and cyclohexane, and groups obtained by removing one or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among them, a group obtained by removing one or more hydrogen atoms from adamantane is preferable.
In the above formula ^(p2), a ^{R 17} and ^{R 19} are each independently a linear or branched alkylene group (preferably an alkylene group having 1 to 5 carbon ^atoms), and the terminal of ^{R 19} The terminal of R ¹⁷ may be bonded.
In this case, a cyclic group is formed by R ¹⁷ , R ¹⁹ , the oxygen atom to which R ¹⁹ is bonded, and the carbon atom to which the oxygen atom and R ¹⁷ are bonded. The cyclic group is preferably a 4-7 membered ring, and more preferably a 4-6 membered ring. Specific examples of the cyclic group include a tetrahydropyranyl group and a tetrahydrofuranyl group.

  Specific examples of the acetal type acid dissociable, dissolution inhibiting group include groups represented by the following formulas (p3-1) to (p3-12).

［式中、Ｒ^１３は水素原子またはメチル基であり、ｇは前記と同じである。］

[Wherein, R ¹³ represents a hydrogen atom or a methyl group, and g is the same as defined above. ]

Specific examples of the structural unit (a11) in which X ¹ is a tertiary alkyl ester type acid dissociable, dissolution inhibiting group include the following formulas (a1-1-1) to (a1-1-31): The structural unit represented by these is mentioned.
Specific examples of those in which X ¹ is an acetal type acid dissociable, dissolution inhibiting group include structural units represented by the following formulas (a1-2-1) to (a1-2-24).
In the following formulas, R ^α represents a hydrogen atom, a methyl group or a trifluoromethyl group.

In the present invention, as the structural unit (a11), X ¹ is preferably a tertiary alkyl ester type acid dissociable, dissolution inhibiting group, and among them, (i) the ring of the monovalent aliphatic cyclic group described above. What is a group having a tertiary carbon atom on the skeleton is preferable. That is, the structural unit (a11) is preferably a structural unit represented by the following general formula (a11-11).

［式中、Ｒは前記と同じであり、Ｒ^２３はアルキル基であり、Ｒ^２４は、当該Ｒ^２４が結合した炭素原子と共に脂肪族環式基を形成する基である。］

[Wherein, R is as defined above, R ²³ is an alkyl group, and R ²⁴ is a group that forms an aliphatic cyclic group together with the carbon atom to which R ²⁴ is bonded. ]

In formula (a11-11), examples of the alkyl group for R ²³ include the same alkyl groups as those described above for R ¹⁴ . As the alkyl group for R ^23, a linear or branched alkyl group is preferable, and an ethyl group or an isopropyl group is most preferable.
R ²⁴ is a group that forms an aliphatic cyclic group together with the carbon atom to which R ²⁴ is bonded. Examples of the aliphatic cyclic group include the same aliphatic cyclic groups as mentioned in the above “acid dissociable, dissolution inhibiting group containing an aliphatic cyclic group”. The aliphatic cyclic group is particularly preferably an aliphatic polycyclic group from the viewpoint of improving etching resistance.
In the above formula (a11-11), the group composed of R ²³ , R ²⁴ and the carbon atom to which they are bonded includes the above-mentioned “(i) monovalent aliphatic cyclic group on the ring skeleton”. Examples thereof include the same groups as those represented by the general formulas (1-1) to (1-9) listed as “group having a tertiary carbon atom”. Among these, those in which the aliphatic cyclic group is a polycyclic group, that is, groups represented by the formulas (1-1) and (1-3) to (1-9) are preferable. The group represented by -1) is preferred.

As the structural unit (a11) contained in the component (A1), 1 type of structural unit may be used, or 2 or more types may be used.
The proportion of the structural unit (a11) in the component (A1) is preferably 1 to 50 mol%, more preferably 2 to 40 mol%, more preferably 3 to 30 with respect to the total of all structural units constituting the component (A). More preferred is mol%, and most preferred is 5 to 20 mol%. By making it within this range, the effect of the present invention can be sufficiently obtained.

-Structural unit (a12):
The structural unit (a12) is represented by the following general formula (a12-1).

［式中、Ｒは前記と同じであり、Ｙ^２は２価の連結基であり、Ｘ^２は酸解離性溶解抑制基である。］

[Wherein, R is as defined above, Y ² is a divalent linking group, and X ² is an acid dissociable, dissolution inhibiting group. ]

In formula (a12-1), R is the same as R in formula (a11-1).
Examples of Y ² include the same as those mentioned as the divalent linking group for R ²⁰ .
In the present invention, the divalent linking group for Y ² is preferably an alkylene group, a divalent aliphatic cyclic group or a divalent linking group containing a hetero atom, and particularly preferably an alkylene group.
When Y ² is an alkylene group, the alkylene group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, and particularly preferably 1 to 4 carbon atoms. It is most preferable that it is number 1-3. Specific examples include the same linear alkylene groups and branched alkylene groups as mentioned above.
When Y ² is a divalent aliphatic cyclic group, the aliphatic cyclic group is the same as the cyclic aliphatic hydrocarbon group mentioned in the above “aliphatic hydrocarbon group containing a ring in the structure”. Can be mentioned.
The aliphatic cyclic group is particularly preferably a group in which two or more hydrogen atoms have been removed from cyclopentane, cyclohexane, norbornane, isobornane, adamantane, tricyclodecane or tetracyclododecane.

When Y ² is a divalent linking group containing a hetero atom, preferred examples of the linking group include —O—, —C (═O) —O—, —C (═O) —, and —O—C. (═O) —O—, —C (═O) —NH—, —NH— (H may be substituted with a substituent such as an alkyl group or an acyl group), —S—, —S ( ═O) ₂ —, —S (═O) ₂ —O—, a group represented by the general formula —A—O—B—, a general formula — [A—C (═O) —O] _d —B— The group etc. which are represented by these are mentioned. Here, A and B are each independently a divalent hydrocarbon group which may have a substituent, and d is an integer of 0 to 3.
When Y ² is —NH—, H may be substituted with a substituent such as an alkyl group or an acyl group. The substituent (alkyl group, acyl group, etc.) preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and particularly preferably 1 to 5 carbon atoms.

In the general formula —A—O—B— or — [A—C (═O) —O] _d —B—, each of A and B independently represents a divalent group that may have a substituent. It is a hydrocarbon group.
Examples of the divalent hydrocarbon group which may have a substituent in A and B are the same as those described above as the “divalent hydrocarbon group which may have a substituent” in R ² . Can be mentioned.
As A, a linear aliphatic hydrocarbon group is preferable, a linear alkylene group is more preferable, a linear alkylene group having 1 to 5 carbon atoms is more preferable, and a methylene group or an ethylene group is particularly preferable. .
B is preferably a linear or branched aliphatic hydrocarbon group, more preferably a methylene group, an ethylene group or an alkylmethylene group. The alkyl group in the alkylmethylene group is preferably a linear alkyl group having 1 to 5 carbon atoms, more preferably a linear alkyl group having 1 to 3 carbon atoms, and most preferably a methyl group.
In the group represented by the formula — [A—C (═O) —O] _d —B—, d is an integer of 0 to 3, preferably an integer of 0 to 2, and 0 or 1 is more. Preferably 1 is most preferred.

In formula (a12-1), X ² is an acid dissociable, dissolution inhibiting group.
Examples of X ² include those similar to X ¹ in formula (a11-1), such as a tertiary alkyl ester type acid dissociable, dissolution inhibiting group, and an acetal type acid dissociable, dissolution inhibiting group.

  More specifically, examples of the structural unit (a12) include structural units represented by general formula (a12-3) shown below and structural units represented by general formula (a12-4).

［式中、Ｒ、Ｙ^２、Ｒ^１’、Ｒ^２’、ｎおよびＹはそれぞれ前記と同じであり、Ｘ’は第３級アルキルエステル型酸解離性溶解抑制基である。］

[Wherein, R, Y ² , R ¹ ′, R ² ′, n and Y are the same as defined above, and X ′ is a tertiary alkyl ester type acid dissociable, dissolution inhibiting group. ]

In the above formula, X ′ is the same as the tertiary alkyl ester type acid dissociable, dissolution inhibiting group exemplified above.
The tertiary alkyl ester-type acid dissociable, dissolution inhibiting group for X ′ is more preferably a group having a tertiary carbon atom on the ring skeleton of the above-mentioned (i) monovalent aliphatic cyclic group. Those in which the cyclic group is a polycyclic group (aliphatic polycyclic group) are particularly preferred. Among these, a group represented by the general formula (1-1) is preferable.
Y is preferably an aliphatic cyclic group, and particularly preferably an aliphatic polycyclic group.

Specific examples of the structural unit represented by the general formula (a12-3) include structural units represented by the following formulas (a1-3-1) to (a1-3-32).
Specific examples of the structural unit represented by the general formula (a12-4) include structural units represented by the following formulas (a1-4-1) to (a1-4-15). .
In the following formulas, R ^α represents a hydrogen atom, a methyl group or a trifluoromethyl group.

As the structural unit (a12), in particular, Y ² in the above formula is an alkylene group, a group represented by the above formula — [A—C (═O) —O] _d —B—, or the above formula —A. What is group represented by -O-B- is preferable.
Preferred examples of the structural unit include a structural unit represented by the following general formula (a12-31), a structural unit represented by the following general formula (a12-32), and a general formula (a12-33). And the like.

［式中、ＲおよびＸ^２はそれぞれ前記と同じであり、Ｙ^２’およびＹ^２”はそれぞれ独立して２価の連結基であり、ｎ”は０〜３の整数である。］

[Wherein, R and X ² are the same as defined above, Y ² ′ and Y ² ″ are each independently a divalent linking group, and n ″ is an integer of 0 to 3. ]

In formula (a12-31), examples of the divalent linking group for Y ² ′ and Y ² ″ include the same groups as those described above for Y ² in formula (a12-1).
Y ² ′ is preferably a divalent hydrocarbon group which may have a substituent, more preferably a linear aliphatic hydrocarbon group, and still more preferably a linear alkylene group. Among these, a linear alkylene group having 1 to 5 carbon atoms is preferable, and a methylene group or an ethylene group is most preferable.
Y ² ″ is preferably a divalent hydrocarbon group which may have a substituent, more preferably a linear aliphatic hydrocarbon group, and still more preferably a linear alkylene group. A linear alkylene group of 1 to 5 is preferable, and a methylene group and an ethylene group are most preferable.
Examples of the acid dissociable, dissolution inhibiting group for X ² are the same as those described above.
X ² in formula (a12-31) is preferably a tertiary alkyl ester-type acid dissociable, dissolution inhibiting group, and a tertiary carbon on the ring skeleton of (i) the monovalent aliphatic cyclic group described above. A group having an atom is more preferable, and a group in which the aliphatic cyclic group is a polycyclic group (aliphatic polycyclic group) is particularly preferable. Among these, a group represented by the general formula (1-1) is preferable.
n ″ is an integer of 0 to 3, preferably an integer of 0 to 2, more preferably 0 or 1, and most preferably 0.

  As the structural unit represented by the formula (a12-31), the following general formula (a12-31-1) including the structural units represented by the above formulas (a1-3-13) to (a1-3-16). The structural unit represented by the following general formula (a12-31-2) including the structural units represented by the formulas (a1-3-17) to (a1-3-24) A structural unit represented by the following general formula (a12-31-3) including the structural unit represented by the formula (a1-3-29) or (a1-3-31), and the formula (a1-3) The structural unit represented by the following general formula (a12-31-4) including the structural unit represented by -30) or (a1-3-32) is preferable. Among these, the structural unit represented by the formula (a12-31-1) is preferable.

［式中、ＲおよびＲ^１４はそれぞれ前記と同じであり、ａは１〜１０の整数であり、ｂは１〜１０の整数であり、ｔは０〜３の整数である。］

[Wherein, R and R ¹⁴ are the same as defined above, a is an integer of 1 to 10, b is an integer of 1 to 10, and t is an integer of 0 to 3, respectively. ]

In formulas (a12-31-1) to (a12-31-4), a is preferably an integer of 1 to 8, more preferably an integer of 1 to 5, and most preferably 1 or 2.
b is preferably an integer of 1 to 8, preferably an integer of 1 to 5, and particularly preferably 1 or 2.
t is preferably an integer of 1 to 3, and 1 or 2 is particularly preferable.

［式中、Ｒ、Ｒ^１４は前記と同じであり、Ｒ^１２は水素原子またはメチル基であり、ａは前記と同じである。］

[Wherein, R and R ¹⁴ are the same as defined above, R ¹² is a hydrogen atom or a methyl group, and a is the same as defined above. ]

［式中、Ｒ、Ｒ^１４およびａはそれぞれ前記と同じであり、Ｒ^１２は水素原子またはメチル基であり、ｎ’は０〜３の整数である。］

[Wherein, R, R ¹⁴ and a are the same as defined above, R ¹² represents a hydrogen atom or a methyl group, and n ′ represents an integer of 0 to 3. ]

In formulas (a12-32) to (a12-33), R ¹² is preferably a hydrogen atom.
a is the same as a in the formulas (a12-31-1) to (a12-31-4).
n ′ is preferably 1 or 2, and most preferably 2.
Specific examples of the structural unit represented by the formula (a12-31) include the structural units represented by the formulas (a1-3-25) to (a1-3-26).
Specific examples of the structural unit represented by Formula (a12-32) include the structural units represented by Formulas (a1-3-27) to (a1-3-28).

As the structural unit (a12) contained in the component (A1), 1 type of structural unit may be used, or 2 or more types may be used.
The proportion of the structural unit (a12) in the component (A1) is preferably 1 to 55 mol%, more preferably 5 to 50 mol%, more preferably 5 to 45, based on the total of all structural units constituting the component (A). More preferred is mol%, and most preferred is 5 to 35 mol%. By making it within this range, the effect of the present invention can be sufficiently obtained.

In the present invention, the total proportion of the structural unit (a11) and the structural unit (a12) in the component (A1) is 20 to 50 mol% with respect to the total of all the structural units constituting the component (A). It is preferably 25 to 45 mol%, more preferably 25 to 40 mol%. By setting it to the lower limit value or more of the range, a good resist pattern can be obtained when the resist composition is used, and by setting the upper limit value or less, the balance with other structural units is good and the lithography characteristics are good. improves.
The ratio (molar ratio) of the structural unit (a11) and the structural unit (a12) in the component (A1) is within the range of structural unit (a11): structural unit (a12) = 8: 2 to 1: 9. It is preferable that it is in the range of 8: 2 to 1.5: 8.5, more preferably in the range of 8: 2 to 2: 8. By making the above range. Good resolution and resist pattern shape.

The component (A1) may have other structural units other than the structural units (a10), (a11), and (a12) as long as the effects of the present invention are not impaired.
The other structural unit is not particularly limited as long as it is another structural unit that is not classified into the above structural units (a10), (a11), and (a12). For ArF excimer laser, for KrF excimer laser, Many things conventionally known as what is used for resist resin for EUV, EB, etc. can be used.
Preferred examples of the other structural unit include the structural unit (a3), the structural unit (a4), the structural unit (a5), the structural unit (a6), and the structural unit (a7) shown below.

-Structural unit (a3):
The structural unit (a3) is a structural unit derived from an acrylate ester containing a polar group-containing aliphatic hydrocarbon group. When the component (A1) has the structural unit (a3), the hydrophilicity of the component (A1) is increased, the affinity with the developer is increased, the alkali solubility in the exposed area is improved, and the resolution is improved. Contributes to improvement.

Here, the “structural unit derived from an acrylate ester” means a structural unit formed by cleavage of an ethylenic double bond of an acrylate ester.
“Acrylic acid esters” include those in which a hydrogen atom is bonded to the carbon atom at the α-position, and those in which a substituent (atom or group other than a hydrogen atom) is bonded to the carbon atom in the α-position. Include concepts. Examples of the substituent include an alkyl group and a halogenated alkyl group. Note that the α-position (α-position carbon atom) of a structural unit derived from an acrylate ester means a carbon atom to which a carbonyl group is bonded, unless otherwise specified.
The alkyl group as a substituent bonded to the α-position carbon atom is preferably an alkyl group having 1 to 5 carbon atoms, specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, Examples thereof include linear or branched alkyl groups such as isobutyl group, tert-butyl group, pentyl group, isopentyl group, and neopentyl group.
Specific examples of the halogenated alkyl group include groups in which some or all of the hydrogen atoms of the alkyl group have been substituted with halogen atoms. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable.
In the structural unit derived from an acrylate ester, the α-position of the acrylate ester is bonded to a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. It is more preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a fluorinated alkyl group having 1 to 5 carbon atoms, and from the viewpoint of industrial availability, it is preferably a hydrogen atom or a methyl group. Most preferred.

In the structural unit (a3), examples of the polar group include a hydroxyl group, a cyano group, a carboxy group, and a hydroxyalkyl group in which part of the hydrogen atoms of the alkyl group is substituted with a fluorine atom. A hydroxyl group is particularly preferable.
Examples of the aliphatic hydrocarbon group include a linear or branched hydrocarbon group having 1 to 10 carbon atoms (preferably an alkylene group), and a polycyclic aliphatic hydrocarbon group (aliphatic polycyclic group). Is mentioned. As the aliphatic polycyclic group, for example, a resin for a resist composition for ArF excimer laser can be appropriately selected and used from among many proposed ones. The aliphatic polycyclic group preferably has 7 to 30 carbon atoms. Specific examples include groups in which two or more hydrogen atoms have been removed from bicycloalkane, tricycloalkane, tetracycloalkane, or the like. Specific examples include groups in which two or more hydrogen atoms have been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among these polycyclic groups, there are groups in which two or more hydrogen atoms have been removed from adamantane, groups in which two or more hydrogen atoms have been removed from norbornane, and groups in which two or more hydrogen atoms have been removed from tetracyclododecane. Industrially preferable.
The structural unit (a3) includes, among the above, an aliphatic polycyclic group containing a hydroxyalkyl group in which a part of hydrogen atoms of a hydroxyl group, a cyano group, a carboxy group, or an alkyl group is substituted with a fluorine atom. A structural unit derived from an acrylate ester is more preferred.

  The structural unit (a3) is derived from a hydroxyethyl ester of acrylic acid when the hydrocarbon group in the polar group-containing aliphatic hydrocarbon group is a linear or branched hydrocarbon group having 1 to 10 carbon atoms. When the hydrocarbon group is a polycyclic group, a structural unit represented by the following formula (a3-1), a structural unit represented by (a3-2), (a3-3) The structural unit etc. which are represented by these are mentioned as a preferable thing.

（式中、Ｒは前記と同じであり、ｊは１〜３の整数であり、ｋは１〜３の整数であり、ｔ’は１〜３の整数であり、ｌは１〜５の整数であり、ｓは１〜３の整数である。）

(In the formula, R is the same as above, j is an integer of 1 to 3, k is an integer of 1 to 3, t 'is an integer of 1 to 3, and l is an integer of 1 to 5) And s is an integer of 1 to 3.)

In formula (a3-1), j is preferably 1 or 2, and more preferably 1. When j is 2, it is preferable that the hydroxyl group is bonded to the 3rd and 5th positions of the adamantyl group. When j is 1, it is preferable that the hydroxyl group is bonded to the 3-position of the adamantyl group.
j is preferably 1, and a hydroxyl group bonded to the 3-position of the adamantyl group is particularly preferred.
In formula (a3-2), k is preferably 1. The cyano group is preferably bonded to the 5th or 6th position of the norbornyl group.
In formula (a3-3), t ′ is preferably 1. l is preferably 1. s is preferably 1. These preferably have a 2-norbornyl group or a 3-norbornyl group bonded to the terminal of the carboxy group of acrylic acid. The fluorinated alkyl alcohol is preferably bonded to the 5th or 6th position of the norbornyl group.

-Structural unit (a4):
The structural unit (a4) is a structural unit derived from an acrylate ester containing a non-acid-dissociable aliphatic polycyclic group. Here, “acid non-dissociable” means not dissociating by the action of an acid generated from the component (B).
Examples of the aliphatic polycyclic group in the structural unit (a4) include those similar to those exemplified in the case of the structural unit (a3). For the ArF excimer laser and the KrF excimer laser ( A number of hitherto known materials can be used as the resin component of the resist composition (preferably for ArF excimer laser). In particular, at least one selected from a tricyclodecanyl group, an adamantyl group, a tetracyclododecanyl group, an isobornyl group, and a norbornyl group is preferable in terms of industrial availability. These aliphatic polycyclic groups may have a linear or branched alkyl group having 1 to 5 carbon atoms as a substituent.
Specific examples of the structural unit (a4) include structural units represented by general formulas (a4-1) to (a4-5) shown below.

［式中、Ｒは前記と同じである。］

[Wherein, R is the same as defined above. ]

-Structural unit (a5):
The structural unit (a5) is a structural unit derived from hydroxystyrene.
Here, “structural unit derived from hydroxystyrene” means a structural unit formed by cleavage of an ethylenic double bond of hydroxystyrene.
“Hydroxystyrene” refers to hydroxystyrene (= a compound in which at least one hydroxyl group is bonded to the benzene ring of vinylbenzene; hereinafter referred to as unsubstituted hydroxystyrene) as well as α of the unsubstituted hydroxystyrene. It is a concept that includes a hydrogen atom bonded to a carbon atom at the position substituted with a substituent (α-substituted hydroxystyrene) and derivatives thereof. That is, it is simply referred to as “hydroxystyrene”, and if not particularly limited, the “hydroxystyrene” may be any of unsubstituted hydroxystyrene, α-substituted hydroxystyrene, and derivatives thereof. The α-position carbon atom of hydroxystyrene means a carbon atom to which a benzene ring is bonded unless otherwise specified.
Examples of the substituent that may be bonded to the α-position carbon atom in the α-substituted hydroxystyrene include an alkyl group having 1 to 5 carbon atoms, and an alkyl group having 1 to 5 carbon atoms is particularly preferable. The alkyl group is preferably a linear or branched alkyl group, and specifically includes a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, and pentyl. Group, isopentyl group, neopentyl group and the like.
Examples of the derivative include compounds in which a substituent is bonded to the benzene ring of unsubstituted hydroxystyrene or α-substituted hydroxystyrene.
Preferred examples of the structural unit (a5) include structural units represented by general formula (a5-1) shown below.

［式中、Ｒ^１およびＲ^３はそれぞれ前記と同じであり、ｐは１〜３の整数であり、ｑは０〜４の整数であり、ｐ＋ｑは１〜５である。］

[Wherein, R ¹ and R ³ are the same as defined above, p is an integer of 1 to 3, q is an integer of 0 to 4, and p + q is 1 to 5, respectively. ]

Wherein ^(a5-1), R 1, ^{R 3} are the same as ^R 1, ^{R 3} in each of the formulas (A10-1).
p is an integer of 1 to 3, q is an integer of 0 to 4, and p + q is 1 to 5. However, p + q is 1-5.
p is most preferably 1.
q is preferably an integer of 0 to 2, more preferably 0 or 1, and industrially particularly preferably 0.
In formula (a5-1), the bonding position of the hydroxyl group in the phenyl group is not particularly limited. When p is 1, any of the o-position, m-position and p-position may be used, and the p-position is preferred because it is readily available and inexpensive. When p is 2 or 3, any bonding position can be combined.
Moreover, the bonding position of R ^{2 in} the phenyl group is not particularly limited. When q is 1, any of the o-position, m-position, and p-position may be used. When q is an integer greater than or equal to 2, arbitrary bond positions can be combined.
When q is an integer of 2 or more, the plurality of R ² may be the same or different from each other.

Structural unit (a6):
The structural unit (a6) is a structural unit derived from styrene. By having the structural unit (a6), heat resistance and dry etching resistance are improved when a resist composition is obtained. Moreover, the solubility with respect to an alkali developing solution can be adjusted by adjusting content of a structural unit (a6).
Here, in the present specification, the “structural unit derived from styrene” means a structural unit formed by cleavage of an ethylenic double bond of styrene.
“Styrene” means styrene in a narrow sense (= vinylbenzene; hereinafter sometimes referred to as unsubstituted styrene), and a hydrogen atom bonded to the α-position carbon atom of the unsubstituted styrene is substituted with a substituent. The concept includes products (α-substituted styrene) and derivatives thereof. That is, it is simply referred to as “styrene”, and there is no particular limitation. The “styrene” may be any of unsubstituted styrene, α-substituted styrene, and derivatives thereof. The α-position carbon atom of styrene means a carbon atom to which a benzene ring is bonded unless otherwise specified.
In the α-substituted styrene, examples of the substituent which may be bonded to the α-position carbon atom include an alkyl group having 1 to 5 carbon atoms, and an alkyl group having 1 to 5 carbon atoms is particularly preferable. The alkyl group is preferably a linear or branched alkyl group, and specifically includes a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, and pentyl. Group, isopentyl group, neopentyl group and the like.
Examples of the derivative include those in which a substituent is bonded to the benzene ring of unsubstituted styrene or α-substituted styrene.
Preferred examples of the structural unit (a6) include structural units represented by general formula (a6-1) shown below.

［式中、Ｒ^１およびＲ^３はそれぞれ前記と同じであり、ｒは０〜５の整数である。］

[Wherein, R ¹ and R ³ are the same as defined above, and r is an integer of 0 to 5, respectively. ]

Wherein ^(a6-1), R 1, ^{R 3} are the same as ^R 1, ^{R 3} in each of the formulas (A10-1).
r is preferably an integer of 0 to 3, more preferably 0 or 1, and most preferably 0 industrially.

-Structural unit (a7):
The structural unit (a7) is a structural unit having a site that generates an acid upon exposure.
Examples of the structural unit (a7) include structural units described in JP-A-2006-45311.

In the component (A1), one of these other structural units may be used alone, or two or more of these structural units may be used in combination.
However, in consideration of the effect of the present invention, the total proportion of the structural units (a10), (a11) and (a12) in the component (A1) is based on the total of all structural units constituting the component (A1). 70 mol% or more, preferably 90 mol% or more, more preferably 100 mol%. That is, it is particularly preferable that the component (A1) does not contain any other structural unit other than the structural units (a10), (a11), and (a12).

The component (A1) is preferably a copolymer having the structural units (a10), (a11) and (a12). Examples of such a copolymer include the structural units (a10), (a11) and (a12). The copolymer which consists of is mentioned. These copolymers may further have at least one structural unit selected from the group consisting of the structural units (a3) to (a7).
The component (A1) is particularly preferably a copolymer having three structural units represented by the following general formula (A1-11) or (A1-12), and a copolymer comprising the three structural units. Most preferred is a polymer.

［式中、Ｒ^１、Ｒ、ａおよびＲ^２１はそれぞれ前記と同じであり、Ｒ^１４’およびＲ^１４”はそれぞれ独立にアルキル基である。］

[Wherein R ¹ , R, a and R ²¹ are the same as defined above, and R ¹⁴ ′ and R ¹⁴ ″ are each independently an alkyl group.]

R ^{14 ',} the alkyl group in ^{R 14} ", the formula (1-1) to (1-9) the same as ^{R 14} in the like.

The component (A1) can be produced using a known production method. For example, a known radical polymerization using a monomer for deriving each structural unit using a radical polymerization initiator such as azobisisobutyronitrile (AIBN), etc. Can be produced through a polymerization step.
Further, for the component (A1), in the polymerization, a chain transfer agent such as HS—CH ₂ —CH ₂ —CH ₂ —C (CF ₃ ) ₂ —OH is used in combination, so that the terminal A —C (CF ₃ ) ₂ —OH group may be introduced into the. As described above, a copolymer into which a hydroxyalkyl group in which a part of hydrogen atoms of an alkyl group is substituted with a fluorine atom is introduced has reduced development defects and LER (line edge roughness: uneven unevenness of line side walls). It is effective in reducing
A commercially available monomer may be used as the monomer for deriving each structural unit, or the monomer may be synthesized using a known method.

The mass average molecular weight (Mw) of the component (A1) (polystyrene conversion standard by gel permeation chromatography) is not particularly limited, but is preferably 2000 to 50000, more preferably 2000 to 30000, and 2000 to 10000. Particularly preferred is 3000 to 6000, most preferred. When it is smaller than the upper limit of this range, it has sufficient solubility in a resist solvent to be used as a resist, and when it is larger than the lower limit of this range, dry etching resistance and resist pattern cross-sectional shape are good. In particular, when the molecular weight is 3000 to 6000, the pattern shape and LWR are good.
Further, the dispersity (Mw / Mn) is preferably 1.0 to 5.0, more preferably 1.0 to 3.0, and most preferably 1.2 to 2.5. In addition, Mn shows a number average molecular weight.

The component (A1) contained in the component (A) may be one type or two or more types. In this invention, it is preferable that 2 or more types of (A1) component is included. This improves the effects of the present invention, such as LWR. Moreover, the protection rate of the whole (A) component can be easily adjusted by mixing 2 or more types from which the protection rate (ratio (mol%) of the structural unit which has an acid dissociable dissolution inhibiting group) differs.
In view of the effects of the present invention, the proportion of the component (A1) in the component (A) is preferably 50% by mass or more, more preferably 75% by mass, and 80% by mass with respect to the total mass of the component (A). More preferably, it may be 100% by mass.

The resist composition of the present invention does not correspond to the component (A1) as the component (A), and is a base material component that increases solubility in an alkaline developer due to the action of an acid (hereinafter referred to as “component (A2)”). May be contained.
The component (A2) is not particularly limited, and many conventionally known base components for chemically amplified positive resist compositions (for example, for ArF excimer laser, for KrF excimer laser, for EB, Any base resin selected from EUV base resins) may be used. Moreover, you may contain the nonpolymer (low molecular compound) whose molecular weight is 500-4000.
(A2) A component may be used individually by 1 type and may be used in combination of 2 or more type.

  In the resist composition of the present invention, the content of the component (A) may be adjusted according to the resist film thickness to be formed.

<(B) component>
The component (B) is not particularly limited, and those that have been proposed as acid generators for chemically amplified resists can be used. Examples of such acid generators include onium salt acid generators such as iodonium salts and sulfonium salts, oxime sulfonate acid generators, bisalkyl or bisarylsulfonyldiazomethanes, and poly (bissulfonyl) diazomethanes. There are various known diazomethane acid generators, nitrobenzyl sulfonate acid generators, imino sulfonate acid generators, disulfone acid generators, and the like.
As the onium salt acid generator, for example, a compound represented by the following general formula (b-1) or (b-2) can be used.

［式中、Ｒ^１”〜Ｒ^３”，Ｒ^５”〜Ｒ^６”は、それぞれ独立に、置換基を有していてもよいアリール基またはアルキル基を表し；式（ｂ−１）におけるＲ^１”〜Ｒ^３”のうち、いずれか２つが相互に結合して式中のイオウ原子と共に環を形成してもよく；Ｒ^４”は、置換基を有していても良いアルキル基、ハロゲン化アルキル基、アリール基、またはアルケニル基を表し；Ｒ^１”〜Ｒ^３”のうち少なくとも１つはアリール基を表し、Ｒ^５”〜Ｒ^６”のうち少なくとも１つはアリール基を表す。］

[Wherein, R ¹ ″ to R ³ ″ and R ⁵ ″ to R ⁶ ″ each independently represents an aryl group or an alkyl group which may have a substituent; R in the formula (b-1) Any one of ¹ ″ to R ³ ″ may be bonded to each other to form a ring together with the sulfur atom in the formula; R ⁴ ″ represents an alkyl group which may have a substituent, a halogen atom; An alkyl group, an aryl group, or an alkenyl group; at least one of R ¹ ″ to R ³ ″ represents an aryl group, and at least one of R ⁵ ″ to R ⁶ ″ represents an aryl group.]

In formula (b-1), R ¹ ″ to R ³ ″ each independently represents an aryl group or an alkyl group which may have a substituent. In addition, any two of R ¹ ″ to R ³ ″ in formula (b-1) may be bonded to each other to form a ring together with the sulfur atom in the formula.
Further, at least one of R ¹ ″ to R ³ ″ represents an aryl group. Of R ¹ ″ to R ³ ″, two or more are preferably aryl groups, and most preferably all of R ¹ ″ to R ³ ″ are aryl groups.

The aryl group for R ¹ ″ to R ³ ″ is not particularly limited, and examples thereof include an aryl group having 6 to 20 carbon atoms. The aryl group is preferably an aryl group having 6 to 10 carbon atoms because it can be synthesized at a low cost. Specific examples include a phenyl group and a naphthyl group.
The aryl group may have a substituent. “Having a substituent” means that part or all of the hydrogen atoms of the aryl group are substituted with a substituent, and examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a hydroxyl group, An alkoxyalkyloxy group, —O—R ⁵⁰ —CO—O—R ^{51 wherein} R ⁵⁰ is an alkylene group and R ⁵¹ is an acid-dissociable group; ] Etc. are mentioned.
The alkyl group that may be substituted for the hydrogen atom of the aryl group is preferably an alkyl group having 1 to 5 carbon atoms, and is a methyl group, ethyl group, propyl group, n-butyl group, or tert-butyl group. Is most preferred.
As the alkoxy group that may be substituted for the hydrogen atom of the aryl group, an alkoxy group having 1 to 5 carbon atoms is preferable, and a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, A tert-butoxy group is preferable, and a methoxy group and an ethoxy group are most preferable.
The halogen atom that may be substituted with the hydrogen atom of the aryl group is preferably a fluorine atom.

Examples of the alkoxyalkyloxy group in which the hydrogen atom of the aryl group may be substituted include, for example, —O—C (R ⁴⁷ ) (R ⁴⁸ ) —O—R ^{49 wherein} R ⁴⁷ and R ⁴⁸ are each It is independently a hydrogen atom or a linear or branched alkyl group, R ⁴⁹ is an alkyl group, and R ⁴⁸ and R ⁴⁹ may be bonded to each other to form one ring structure. Provided ^that at least one of ^{R 47} and ^{R 48} are hydrogen atoms. ].
In R ⁴⁷ and R ⁴⁸ , the alkyl group preferably has 1 to 5 carbon atoms, preferably an ethyl group or a methyl group, and most preferably a methyl group.
One of R ⁴⁷ and R ⁴⁸ is preferably a hydrogen atom, the other is preferably a hydrogen atom or a methyl group, and both R ⁴⁷ and R ⁴⁸ are particularly preferably hydrogen atoms.
The alkyl group for R ⁴⁹ preferably has 1 to 15 carbon atoms and may be linear, branched or cyclic.
The linear or branched alkyl group for R ⁴⁹ preferably has 1 to 5 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, an n-butyl group, and a tert-butyl group. Can be mentioned.
The cyclic alkyl group for R ⁴⁹ preferably has 4 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms.
Specifically, monocycloalkane, bicycloalkane, tricycloalkane, tetracycloalkane, etc., which may or may not be substituted with an alkyl group having 1 to 5 carbon atoms, a fluorine atom or a fluorinated alkyl group, etc. And a group obtained by removing one or more hydrogen atoms from the polycycloalkane. Examples of the monocycloalkane include cyclopentane and cyclohexane. Examples of the polycycloalkane include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among them, a group obtained by removing one or more hydrogen atoms from adamantane is preferable.
R ⁴⁸ and R ⁴⁹ may be bonded to each other to form one ring structure. In this case, the R ⁴⁸ and R ^49, the oxygen atom having R ⁴⁹ is bonded, a cyclic group is formed by the carbon atom having the oxygen atom and R ⁴⁸ are bonded. The cyclic group is preferably a 4-7 membered ring, and more preferably a 4-6 membered ring.

In —O—R ⁵⁰ —CO—O—R ⁵¹ in which the hydrogen atom of the aryl group may be substituted, the alkylene group in R ⁵⁰ is preferably a linear or branched alkylene group, and the carbon number thereof Is preferably 1-5. Examples of the alkylene group include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, and a 1,1-dimethylethylene group.
The acid dissociable group in R ⁵¹ is not particularly limited as long as it is an organic group that can be dissociated by the action of an acid (an acid generated from the component (B) during exposure). For example, in the general formula (a11-1), those similar to the acid dissociable, dissolution inhibiting groups as those exemplified as X ¹ can be mentioned. Among them, the tertiary alkyl ester type is preferable.

The alkyl group for R 1 ^{"~R 3",} is not particularly limited, for example, linear C1-10, branched or cyclic alkyl group, and the like. It is preferable that it is C1-C5 from the point which is excellent in resolution. Specific examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an n-pentyl group, a cyclopentyl group, a hexyl group, a cyclohexyl group, a nonyl group, and a decanyl group. A methyl group is preferable because it is excellent in resolution and can be synthesized at low cost.
The alkyl group may have a substituent. “Having a substituent” means that part or all of the hydrogen atoms of the alkyl group are substituted with a substituent, and the substituent may be a substituent that the aryl group may have. The thing similar to what was mentioned as a group is mentioned.

When any two of R ¹ ″ to R ³ ″ in formula (b-1) are bonded to each other to form a ring together with the sulfur atom in the formula, a 3 to 10 membered ring including the sulfur atom is formed. It is preferable that a 5- to 7-membered ring is formed.
When any two of R ¹ ″ to R ³ ″ in formula (b-1) are bonded to each other to form a ring together with the sulfur atom in the formula, the remaining one may be an aryl group preferable. Examples of the aryl group are the same as the aryl groups of R ¹ ″ to R ³ ″.

Of the cation moieties of the compound represented by formula (b-1), when R ¹ ″ to R ³ ″ are all phenyl groups that may have a substituent, that is, the cation moiety is triphenylmethane. Specific examples of preferred skeletons include cation moieties represented by the following formulas (I-1-1) to (I-1-8).
Moreover, what substituted a part or all of the phenyl group in these cation parts with the naphthyl group which may have a substituent is mentioned as a preferable thing. Of the three phenyl groups, 1 or 2 is preferably substituted with the naphthyl group.

Moreover, among the cation moieties of the compound represented by the formula (b-1), any two of R ¹ ″ to R ³ ″ are bonded to each other to form a ring together with the sulfur atom in the formula. Preferable specific examples of the case include, for example, cation moieties represented by the following formulas (I-1-10) to (I-1-11).
In the following formula (I-1-10), R ⁹ is a phenyl group, a naphthyl group, or an alkyl group having 1 to 5 carbon atoms which may have a substituent.
In the following formula (I-1-11), R ¹⁰ represents a phenyl group, a naphthyl group, an alkyl group having 1 to 5 carbon atoms, an alkoxy group, or a hydroxyl group, which may have a substituent.
u is an integer of 1 to 3, and 1 or 2 is most preferable.

［式中、Ｒ^９は、置換基を有していてもよいフェニル基、ナフチル基または炭素数１〜５のアルキル基であり、Ｒ^１０は、置換基を有していてもよいフェニル基、ナフチル基、炭素数１〜５のアルキル基、アルコキシ基または水酸基であり、ｕは１〜３の整数である。］

[Wherein, R ⁹ is a phenyl group optionally having a substituent, a naphthyl group or an alkyl group having 1 to 5 carbon atoms, and R ¹⁰ is a phenyl group optionally having a substituent, A naphthyl group, an alkyl group having 1 to 5 carbon atoms, an alkoxy group or a hydroxyl group, and u is an integer of 1 to 3; ]

R 4 ^"is an optionally substituted alkyl group, a halogenated alkyl group, an aryl group or an alkenyl group.
The alkyl group for R ⁴ ″ may be linear, branched or cyclic.
The linear or branched alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 4 carbon atoms.
The cyclic alkyl group preferably has 4 to 15 carbon atoms, more preferably 4 to 10 carbon atoms, and most preferably 6 to 10 carbon atoms.
Examples of the halogenated alkyl group for R ⁴ ″ include groups in which part or all of the hydrogen atoms of the linear, branched, or cyclic alkyl group have been substituted with halogen atoms. A fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned, A fluorine atom is preferable.
In the halogenated alkyl group, the ratio of the number of halogen atoms to the total number of halogen atoms and hydrogen atoms contained in the halogenated alkyl group (halogenation rate (%)) is preferably 10 to 100%. 50 to 100% is preferable, and 100% is most preferable. The higher the halogenation rate, the better the acid strength.
The aryl group for R ⁴ ″ is preferably an aryl group having 6 to 20 carbon atoms.
The alkenyl group in R ⁴ ″ is preferably an alkenyl group having 2 to 10 carbon atoms.
In the above R ⁴ ″, “optionally substituted” means one of hydrogen atoms in the linear, branched or cyclic alkyl group, halogenated alkyl group, aryl group, or alkenyl group. It means that part or all may be substituted with a substituent (an atom or group other than a hydrogen atom).
The number of substituents in R ⁴ ″ may be one or two or more.

Examples of the substituent include a halogen atom, a hetero atom, an alkyl group, and a formula: XQ ^1- [wherein Q ¹ is a divalent linking group containing an oxygen atom, and X has a substituent. And a hydrocarbon group having 3 to 30 carbon atoms. ] Etc. which are represented by these.
Examples of the halogen atom and alkyl group include the same groups as those described above for R ⁴ ″ as the halogen atom and alkyl group in the halogenated alkyl group.
Examples of the hetero atom include an oxygen atom, a nitrogen atom, and a sulfur atom.

X-Q 1 ^- In the group represented by, Q ¹ represents a divalent linking group containing an oxygen atom.
Q ¹ may contain an atom other than an oxygen atom. Examples of atoms other than oxygen atoms include carbon atoms, hydrogen atoms, oxygen atoms, sulfur atoms, and nitrogen atoms.
Examples of the divalent linking group containing an oxygen atom include an oxygen atom (ether bond; —O—), an ester bond (—C (═O) —O—), and an amide bond (—C (═O) —NH. -), A carbonyl group (-C (= O)-), a non-hydrocarbon oxygen atom-containing linking group such as a carbonate bond (-O-C (= O) -O-); the non-hydrocarbon oxygen atom Examples include a combination of a containing linking group and an alkylene group.
Examples of the combination include —R ⁹¹ —O—, —R ⁹² —O—C (═O) —, —C (═O) —O—R ⁹³ —, —C (═O) —O—R. ⁹³ —O—C (═O) — (wherein R ^{91 to} R ⁹³ are each independently an alkylene group).
The alkylene group for R ^{91 to} R ⁹³ is preferably a linear or branched alkylene group, and the alkylene group preferably has 1 to 12 carbon atoms, more preferably 1 to 5 carbon atoms, and particularly preferably 1 to 3 carbon atoms. preferable.
Specific examples of the alkylene group include a methylene group [—CH ₂ —]; —CH (CH ₃ ) —, —CH (CH ₂ CH ₃ ) —, —C (CH ₃ ) ₂ —, —C ( _{CH 3) (CH 2 CH 3} ) -, - C (CH 3) (CH 2 CH 2 CH 3) -, - C (CH 2 CH 3) 2 - ; alkylethylene groups such as ethylene group _[-CH 2 CH _2— ]; —CH (CH ₃ ) CH ₂ —, —CH (CH ₃ ) CH (CH ₃ ) —, —C (CH ₃ ) ₂ CH ₂ —, —CH (CH ₂ CH ₃ ) CH ₂ — and the like. Alkylethylene groups; trimethylene groups (n-propylene groups) [—CH ₂ CH ₂ CH ₂ —]; alkyls such as —CH (CH ₃ ) CH ₂ CH ₂ — and —CH ₂ CH (CH ₃ ) CH ₂ — trimethylene; tetramethylene group _[-CH 2 _CH 2 C _{2 CH 2 -]; - CH} (CH 3) CH 2 CH 2 CH 2 -, - CH 2 CH (CH 3) CH 2 CH 2 - alkyl tetramethylene group and the like; pentamethylene group _[-CH 2 _CH 2 CH ₂ CH ₂ CH ₂ —] and the like.
Q ¹ is preferably a divalent linking group containing an ester bond or an ether bond. Among them, —R ⁹¹ —O—, —R ⁹² —O—C (═O) —, —C (═O) — O—, —C (═O) —O—R ⁹³ — or —C (═O) —O—R ⁹³ —O—C (═O) — is preferred.

In the group represented by XQ ^1- , the hydrocarbon group of X may be an aromatic hydrocarbon group or an aliphatic hydrocarbon group.
The aromatic hydrocarbon group is a hydrocarbon group having an aromatic ring. The aromatic hydrocarbon group preferably has 3 to 30 carbon atoms, more preferably 5 to 30, more preferably 5 to 20, particularly preferably 6 to 15, and most preferably 6 to 12. However, the carbon number does not include the carbon number in the substituent.
Specific examples of the aromatic hydrocarbon group include a hydrogen atom from an aromatic hydrocarbon ring such as a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, an anthryl group, and a phenanthryl group. Examples include aryl groups such as aryl group, benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2-naphthylethyl group, etc., from which one is removed. The number of carbon atoms of the alkyl chain in the arylalkyl group is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.
The aromatic hydrocarbon group may have a substituent. For example, a part of carbon atoms constituting the aromatic ring of the aromatic hydrocarbon group may be substituted with a hetero atom, and the hydrogen atom bonded to the aromatic ring of the aromatic hydrocarbon group is substituted with the substituent. May be.
Examples of the former include heteroaryl groups in which some of the carbon atoms constituting the ring of the aryl group are substituted with heteroatoms such as oxygen atoms, sulfur atoms and nitrogen atoms, and aromatic hydrocarbons in the arylalkyl groups Examples include heteroarylalkyl groups in which some of the carbon atoms constituting the ring are substituted with the above heteroatoms.
Examples of the substituent of the aromatic hydrocarbon group in the latter example include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, and an oxygen atom (═O).
The alkyl group as a substituent of the aromatic hydrocarbon group is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. preferable.
The alkoxy group as a substituent of the aromatic hydrocarbon group is preferably an alkoxy group having 1 to 5 carbon atoms, and is a methoxy group, ethoxy group, n-propoxy group, iso-propoxy group, n-butoxy group, tert- A butoxy group is preferable, and a methoxy group and an ethoxy group are most preferable.
Examples of the halogen atom as a substituent for the aromatic hydrocarbon group include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable.
Examples of the halogenated alkyl group as the substituent of the aromatic hydrocarbon group include groups in which part or all of the hydrogen atoms of the alkyl group have been substituted with the halogen atoms.

The aliphatic hydrocarbon group for X may be a saturated aliphatic hydrocarbon group or an unsaturated aliphatic hydrocarbon group. The aliphatic hydrocarbon group may be linear, branched or cyclic.
In X, the aliphatic hydrocarbon group may have a part of the carbon atoms constituting the aliphatic hydrocarbon group substituted by a substituent containing a hetero atom, and the hydrogen atom constituting the aliphatic hydrocarbon group May be substituted with a substituent containing a hetero atom.
The “heteroatom” in X is not particularly limited as long as it is an atom other than a carbon atom and a hydrogen atom, and examples thereof include a halogen atom, an oxygen atom, a sulfur atom, and a nitrogen atom. Examples of the halogen atom include a fluorine atom, a chlorine atom, an iodine atom, and a bromine atom.
The substituent containing a hetero atom may be composed only of the hetero atom, or may be a group containing a group or atom other than the hetero atom.
Specific examples of the substituent for substituting a part of carbon atoms include, for example, —O—, —C (═O) —O—, —C (═O) —, —O—C (═O) —O. -, - C (= O) -NH -, - NH- (H is an alkyl group, may be substituted with a substituent such as an acyl group), - S -, - S (= O) 2 -, - S (= O) ₂ —O— and the like can be mentioned. When the aliphatic hydrocarbon group is cyclic, these substituents may be included in the ring structure.
Specific examples of the substituent that substitutes part or all of the hydrogen atoms include an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, an oxygen atom (═O), and a cyano group.
The alkoxy group is preferably an alkoxy group having 1 to 5 carbon atoms, preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, or a tert-butoxy group, and a methoxy group or an ethoxy group. Is most preferred.
As said halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned, A fluorine atom is preferable.
As the halogenated alkyl group, a part or all of hydrogen atoms of an alkyl group having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an n-butyl group, a tert-butyl group, etc. And a group substituted with a halogen atom.

Examples of the aliphatic hydrocarbon group include a linear or branched saturated hydrocarbon group, a linear or branched monovalent unsaturated hydrocarbon group, or a cyclic aliphatic hydrocarbon group (aliphatic ring). Formula group) is preferred.
The linear saturated hydrocarbon group (alkyl group) preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and most preferably 1 to 10 carbon atoms. Specifically, for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decanyl group, undecyl group, dodecyl group, tridecyl group, isotridecyl group, tetradecyl group Group, pentadecyl group, hexadecyl group, isohexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group, heicosyl group, docosyl group and the like.
The branched saturated hydrocarbon group (alkyl group) preferably has 3 to 20 carbon atoms, more preferably 3 to 15 carbon atoms, and most preferably 3 to 10 carbon atoms. Specifically, for example, 1-methylethyl group, 1-methylpropyl group, 2-methylpropyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, 1-ethylbutyl group, 2-ethylbutyl group, Examples include 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group and the like.

As an unsaturated hydrocarbon group, it is preferable that carbon number is 2-10, 2-5 are preferable, 2-4 are preferable, and 3 is especially preferable. Examples of the linear monovalent unsaturated hydrocarbon group include a vinyl group, a propenyl group (allyl group), and a butynyl group. Examples of the branched monovalent unsaturated hydrocarbon group include a 1-methylpropenyl group and a 2-methylpropenyl group.
Among the above, the unsaturated hydrocarbon group is particularly preferably a propenyl group.

The aliphatic cyclic group may be a monocyclic group or a polycyclic group. The number of carbon atoms is preferably 3 to 30, more preferably 5 to 30, further preferably 5 to 20, particularly preferably 6 to 15, and most preferably 6 to 12.
Specifically, for example, a group in which one or more hydrogen atoms have been removed from a monocycloalkane; a group in which one or more hydrogen atoms have been removed from a polycycloalkane such as bicycloalkane, tricycloalkane, tetracycloalkane, etc. Can be mentioned. More specifically, a group in which one or more hydrogen atoms have been removed from a monocycloalkane such as cyclopentane or cyclohexane; one or more polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. Examples include a group excluding a hydrogen atom.
When the aliphatic cyclic group does not contain a substituent containing a hetero atom in the ring structure, the aliphatic cyclic group is preferably a polycyclic group, and one or more hydrogen atoms from the polycycloalkane are substituted. Excluded groups are preferred, and groups obtained by removing one or more hydrogen atoms from adamantane are most preferred.
When the aliphatic cyclic group includes a substituent containing a hetero atom in the ring structure, examples of the substituent containing a hetero atom include —O—, —C (═O) —O—, —S—. , —S (═O) ₂ — and —S (═O) ₂ —O— are preferable. Specific examples of the aliphatic cyclic group include the following formulas (L1) to (L5), (S1) to (S4), and the like.

［式中、Ｑ”は炭素数１〜５のアルキレン基、−Ｏ−、−Ｓ−、−Ｏ−Ｒ^９４−または−Ｓ−Ｒ^９５−であり、Ｒ^９４およびＲ^９５はそれぞれ独立に炭素数１〜５のアルキレン基であり、ｍは０または１の整数である。］

[Wherein, Q ″ is an alkylene group having 1 to 5 carbon atoms, —O—, —S—, —O—R ⁹⁴ — or —S—R ⁹⁵ —, wherein R ⁹⁴ and R ⁹⁵ are each independently carbon. An alkylene group of 1 to 5 and m is an integer of 0 or 1.]

In the formula, examples of the alkylene group for Q ″, R ⁹⁴ and R ⁹⁵ include the same alkylene groups as those described above for R ^{91 to} R ⁹³ .
In these aliphatic cyclic groups, a part of hydrogen atoms bonded to carbon atoms constituting the ring structure may be substituted with a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, and an oxygen atom (═O).
The alkyl group is preferably an alkyl group having 1 to 5 carbon atoms, particularly preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group.
Examples of the alkoxy group and the halogen atom are the same as those exemplified as the substituent for substituting part or all of the hydrogen atoms.

In the present invention, X is preferably a cyclic group which may have a substituent. The cyclic group may be an aromatic hydrocarbon group which may have a substituent, an aliphatic cyclic group which may have a substituent, or a substituent. It is preferably an aliphatic cyclic group that may be used.
The aromatic hydrocarbon group is preferably a naphthyl group which may have a substituent or a phenyl group which may have a substituent.
As the aliphatic cyclic group which may have a substituent, a polycyclic aliphatic cyclic group which may have a substituent is preferable. The polycyclic aliphatic cyclic group is preferably a group obtained by removing one or more hydrogen atoms from the polycycloalkane, the above (L2) to (L5), (S3) to (S4), and the like.

In the present invention, ^{R 4} ", ^{X-Q 1} - as a substituent preferably has the case, ^{R 4."} The, ^{X-Q 1} -Y 1 - in the Formula, ^{Q 1} and X are the Y ¹ is an optionally substituted alkylene group having 1 to 4 carbon atoms or an optionally substituted fluorinated alkylene group having 1 to 4 carbon atoms. ] Is preferable.
In the group represented by XQ ¹ -Y ^1- , the alkylene group for Y ¹ includes the same alkylene groups as those described above for Q ¹ having 1 to 4 carbon atoms.
Examples of the fluorinated alkylene group include groups in which part or all of the hydrogen atoms of the alkylene group have been substituted with fluorine atoms.
As Y ^1, _{specifically, -CF 2 -, - CF 2} CF 2 -, - CF 2 CF 2 CF 2 -, - CF (CF 3) CF 2 -, - CF (CF 2 CF 3) -, _{-C (CF 3) 2 -,} - CF 2 CF 2 CF 2 CF 2 -, - CF (CF 3) CF 2 CF 2 -, - CF 2 CF (CF 3) CF 2 -, - CF (CF 3) CF (CF ₃ ) —, —C (CF ₃ ) ₂ CF ₂ —, —CF (CF ₂ CF ₃ ) CF ₂ —, —CF (CF ₂ CF ₂ CF ₃ ) —, —C (CF ₃ ) (CF _{2 CF 3) -; - CHF} -, - CH 2 CF 2 -, - CH 2 CH 2 CF 2 -, - CH 2 CF 2 CF 2 -, - CH (CF 3) CH 2 -, - CH (CF 2 _{CF 3) -, - C (} CH 3) (CF 3) -, - CH 2 CH 2 CH 2 CF 2 -, - C H ₂ CH ₂ CF ₂ CF ₂ —, —CH (CF ₃ ) CH ₂ CH ₂ —, —CH ₂ CH (CF ₃ ) CH ₂ —, —CH (CF ₃ ) CH (CF ₃ ) —, —C ( _{CF 3) 2 CH 2 -;} - CH 2 -, - CH 2 CH 2 -, - CH 2 CH 2 CH 2 -, - CH (CH 3) CH 2 -, - CH (CH 2 CH 3) -, - _{C (CH 3) 2 -,} - CH 2 CH 2 CH 2 CH 2 -, - CH (CH 3) CH 2 CH 2 -, - CH 2 CH (CH 3) CH 2 -, - CH (CH 3) CH _{(CH 3) -, - C} (CH 3) 2 CH 2 -, - CH (CH 2 CH 3) CH 2 -, - CH (CH 2 CH 2 CH 3) -, - C (CH 3) (CH 2 CH ₃ ) — and the like.

Y ¹ is preferably a fluorinated alkylene group, and particularly preferably a fluorinated alkylene group in which the carbon atom bonded to the adjacent sulfur atom is fluorinated. Examples of such fluorinated alkylene _{group, -CF 2 -, - CF 2} CF 2 -, - CF 2 CF 2 CF 2 -, - CF (CF 3) CF 2 -, - CF 2 CF 2 CF 2 CF 2 _{-, - CF (CF 3)} CF 2 CF 2 -, - CF 2 CF (CF 3) CF 2 -, - CF (CF 3) CF (CF 3) -, - C (CF 3) 2 CF 2 -, _{-CF (CF 2 CF 3) CF} 2 -; - CH 2 CF 2 -, - CH 2 CH 2 CF 2 -, - CH 2 CF 2 CF 2 -; - CH 2 CH 2 CH 2 CF 2 -, - CH ₂ CH ₂ CF ₂ CF ₂ —, —CH ₂ CF ₂ CF ₂ CF ₂ — and the like can be mentioned.
Of _{these, -CF 2 -, - CF 2} CF 2 -, - CF 2 CF 2 CF 2 -, or _CH 2 _CF 2 CF ₂ - is _{preferable, -CF 2 -, - CF 2} CF 2 - or -CF ₂ CF ₂ CF ₂ - is more preferable, -CF ₂ - is particularly preferred.

The alkylene group or fluorinated alkylene group may have a substituent. An alkylene group or a fluorinated alkylene group has a “substituent” means that part or all of the hydrogen atom or fluorine atom in the alkylene group or fluorinated alkylene group is substituted with an atom or group other than a hydrogen atom and a fluorine atom. Means that
Examples of the substituent that the alkylene group or fluorinated alkylene group may have include an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a hydroxyl group.

In formula (b-2), R ⁵ ″ to R ⁶ ″ each independently represents an aryl group or an alkyl group. At least one of R ⁵ ″ to R ⁶ ″ represents an aryl group. It is preferable that all of R ⁵ ″ to R ⁶ ″ are aryl groups.
As the aryl group for R ⁵ ″ to R ⁶ ″, the same as the aryl groups for R ¹ ″ to R ³ ″ can be used.
Examples of the alkyl group for R ⁵ ″ to R ⁶ ″ include the same as the alkyl group for R ¹ ″ to R ³ ″.
Among these, it is most preferable that all of R ⁵ ″ to R ⁶ ″ are phenyl groups.
"As ^{R 4} in the formula (b-1)" ^{R 4} in the In the formula (b-2) include the same as.

Specific examples of the onium salt acid generators represented by formulas (b-1) and (b-2) include diphenyliodonium trifluoromethanesulfonate or nonafluorobutanesulfonate; bis (4-tert-butylphenyl) iodonium. Trifluoromethane sulfonate or nonafluorobutane sulfonate; triphenylsulfonium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; tri (4-methylphenyl) sulfonium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its Nonafluorobutanesulfonate; dimethyl (4-hydroxynaphthyl) sulfonium trifluoromethanesulfonate, its heptaful Lopropane sulfonate or its nonafluorobutane sulfonate; trifluoromethane sulfonate of monophenyldimethylsulfonium, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; trifluoromethane sulfonate of diphenyl monomethylsulfonium, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate (4-methylphenyl) diphenylsulfonium trifluoromethanesulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; (4-methoxyphenyl) diphenylsulfonium trifluoromethanesulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; Trifluoromethanesulfonate of tri (4-tert-butyl) phenylsulfonium, its heptafluoropropane sulfonate or its nonafluorobutanesulfonate; trifluoromethanesulfonate of diphenyl (1- (4-methoxy) naphthyl) sulfonium, its heptafluoropropane Sulfonate or its nonafluorobutane sulfonate; trifluoromethane sulfonate of di (1-naphthyl) phenylsulfonium, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 1-phenyltetrahydrothiophenium trifluoromethane sulfonate, its heptafluoropropane sulfonate Or nonafluorobutanesulfonate thereof; 1- (4-methylphenyl) ) Tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropane sulfonate 1- (4-methoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate; 1- (4-ethoxynaphthalene-1- Yl) tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropanesulfonate or its nonaflu 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate; 1-phenyltetrahydrothiopyranium trifluoromethanesulfonate , Its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 1- (4-hydroxyphenyl) tetrahydrothiopyranium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 1- (3,5-dimethyl -4-Hydroxyphenyl) tetrahydrothiopyranium trifluoromethanesulfonate, its heptafluoropropanes Honeto or nonafluorobutanesulfonate; 1- (4-methylphenyl) trifluoromethanesulfonate tetrahydrothiophenium Pila chloride, heptafluoropropane sulfonate or its nonafluorobutane sulfonate, and the like.
Moreover, the onium salt which replaced the anion part of these onium salts with alkyl sulfonates, such as methanesulfonate, n-propanesulfonate, n-butanesulfonate, n-octanesulfonate, can also be used.
Moreover, the onium salt which replaced the anion part of these onium salts by the anion part represented by either of following formula (b1)-(b8) can also be used.

［式中、ｐは１〜３の整数であり、ｖ０は０〜３の整数であり、ｑ１〜ｑ２はそれぞれ独立に１〜５の整数であり、ｑ３は１〜１２の整数であり、ｒ１〜ｒ２はそれぞれ独立に０〜３の整数であり、ｇは１〜２０の整数であり、ｔ３は１〜３の整数であり、Ｒ^７は置換基である。］

[Wherein, p is an integer of 1 to 3, v0 is an integer of 0 to 3, q1 to q2 are each independently an integer of 1 to 5, q3 is an integer of 1 to 12, and r1 ~r2 are each independently an integer of 0 to 3, g is an integer of 1 to 20, t3 is an integer from 1 to 3, ^{R 7} is a substituent. ]

［式中、ｐ、Ｒ^７、Ｑ”はそれぞれ前記と同じであり、ｎ１〜ｎ５はそれぞれ独立に０または１であり、ｖ１〜ｖ５はそれぞれ独立に０〜３の整数であり、ｗ１〜ｗ５はそれぞれ独立に０〜３の整数である。］

[Wherein, p, R ⁷ and Q ″ are the same as defined above, n1 to n5 are each independently 0 or 1, v1 to v5 are each independently an integer of 0 to 3, w1 to w5 Are each independently an integer of 0 to 3.]

Examples of the substituent for R ⁷ are the same as those described above as the substituent that the aliphatic hydrocarbon group may have and the substituent that the aromatic hydrocarbon group may have in X. Can be mentioned.
Code (r1 and r2, w1 to w5) attached to R ⁷ when is an integer of 2 or more, a plurality of the ^{R 7} groups may be the same, respectively, may be different.
r1 to r2 and w1 to w5 are each preferably an integer of 0 to 2, and more preferably 0 or 1.
v0 to v5 are preferably 0 to 2, and most preferably 0 or 1.
t3 is preferably 1 or 2, and most preferably 1.
q3 is preferably 1 to 5, more preferably 1 to 3, and most preferably 1.

  Moreover, as an onium salt type | system | group acid generator, in the said general formula (b-1) or (b-2), an anion part is represented by the following general formula (b-3) or (b-4). An onium salt-based acid generator replaced with can also be used (the cation moiety is the same as (b-1) or (b-2)).

［式中、Ｘ”は、少なくとも１つの水素原子がフッ素原子で置換された炭素数２〜６のアルキレン基を表し；Ｙ”、Ｚ”は、それぞれ独立に、少なくとも１つの水素原子がフッ素原子で置換された炭素数１〜１０のアルキル基を表す。］

[Wherein X ″ represents an alkylene group having 2 to 6 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom; Y ″ and Z ″ each independently represent at least one hydrogen atom as a fluorine atom; Represents an alkyl group having 1 to 10 carbon atoms substituted with

X ″ is a linear or branched alkylene group in which at least one hydrogen atom is substituted with a fluorine atom, and the alkylene group has 2 to 6 carbon atoms, preferably 3 to 5 carbon atoms, Most preferably, it has 3 carbon atoms.
Y ″ and Z ″ are each independently a linear or branched alkyl group in which at least one hydrogen atom is substituted with a fluorine atom, and the alkyl group has 1 to 10 carbon atoms, Has 1 to 7 carbon atoms, more preferably 1 to 3 carbon atoms.
The carbon number of the alkylene group of X ″ or the carbon number of the alkyl group of Y ″ and Z ″ is preferably as small as possible because the solubility in the resist solvent is good within the above carbon number range.
In addition, in the alkylene group of X ″ or the alkyl group of Y ″ and Z ″, the strength of the acid increases as the number of hydrogen atoms substituted with fluorine atoms increases, and high-energy light or electron beam of 200 nm or less The ratio of fluorine atoms in the alkylene group or alkyl group, that is, the fluorination rate is preferably 70 to 100%, more preferably 90 to 100%, and most preferably all. Are a perfluoroalkylene group or a perfluoroalkyl group in which a hydrogen atom is substituted with a fluorine atom.

  Moreover, the sulfonium salt which has a cation part represented by the following general formula (b-5) or (b-6) can also be used as an onium salt type | system | group acid generator.

［式中、Ｒ^４１〜Ｒ^４６はそれぞれ独立してアルキル基、アセチル基、アルコキシ基、カルボキシ基、水酸基またはヒドロキシアルキル基であり；ｎ_１〜ｎ_５はそれぞれ独立して０〜３の整数であり、ｎ_６は０〜２の整数である。］

[Wherein R ^{41 to} R ⁴⁶ are each independently an alkyl group, acetyl group, alkoxy group, carboxy group, hydroxyl group or hydroxyalkyl group; n _{1 to} n ₅ are each independently an integer of 0 to 3; There, _{n 6} is an integer of 0-2. ]

In R ^{41 to} R ⁴⁶ , the alkyl group is preferably an alkyl group having 1 to 5 carbon atoms, more preferably a linear or branched alkyl group, and a methyl group, an ethyl group, a propyl group, an isopropyl group, n A butyl group or a tert-butyl group is particularly preferable.
The alkoxy group is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a linear or branched alkoxy group, and particularly preferably a methoxy group or an ethoxy group.
The hydroxyalkyl group is preferably a group in which one or more hydrogen atoms in the alkyl group are substituted with a hydroxy group, and examples thereof include a hydroxymethyl group, a hydroxyethyl group, and a hydroxypropyl group.
When the symbols n _{1 to} n ₆ attached to R ^{41 to} R ⁴⁶ are integers of 2 or more, the plurality of R ^{41 to} R ⁴⁶ may be the same or different.
n ₁ is preferably 0 to 2, more preferably 0 or 1, and still more preferably 0.
n ₂ and n ₃ are preferably each independently 0 or 1, more preferably 0.
n ₄ is preferably 0 to 2, more preferably 0 or 1.
n ₅ is preferably 0 or 1, more preferably 0.
n ₆ is preferably 0 or 1, more preferably 1.

The anion part of the sulfonium salt having a cation part represented by the formula (b-5) or (b-6) is not particularly limited, and is the same as the anion part of the onium salt acid generators proposed so far. It may be a thing. Such anion portion, for example, the general formula (b-1) or the onium salt-based acid generator represented by (b-2) (R 4 "SO 3 -) fluorinated such as alkyl sulfonate ion The anion part represented by the general formula (b-3) or (b-4) and the like.

  In this specification, the oxime sulfonate acid generator is a compound having at least one group represented by the following general formula (B-1), and has a property of generating an acid upon irradiation with radiation. is there. Such oxime sulfonate-based acid generators are frequently used for chemically amplified resist compositions, and can be arbitrarily selected and used.

（式（Ｂ−１）中、Ｒ^３１、Ｒ^３２はそれぞれ独立に有機基を表す。）

(In formula (B-1), R ³¹ and R ³² each independently represents an organic group.)

The organic groups of R ³¹ and R ³² are groups containing carbon atoms, and atoms other than carbon atoms (for example, hydrogen atoms, oxygen atoms, nitrogen atoms, sulfur atoms, halogen atoms (fluorine atoms, chlorine atoms, etc.), etc.) You may have.
As the organic group for R ^31, a linear, branched, or cyclic alkyl group or aryl group is preferable. These alkyl groups and aryl groups may have a substituent. There is no restriction | limiting in particular as this substituent, For example, a fluorine atom, a C1-C6 linear, branched or cyclic alkyl group etc. are mentioned. Here, “having a substituent” means that part or all of the hydrogen atoms of the alkyl group or aryl group are substituted with a substituent.
As an alkyl group, C1-C20 is preferable, C1-C10 is more preferable, C1-C8 is more preferable, C1-C6 is especially preferable, and C1-C4 is the most preferable. As the alkyl group, a partially or completely halogenated alkyl group (hereinafter sometimes referred to as a halogenated alkyl group) is particularly preferable. The partially halogenated alkyl group means an alkyl group in which a part of hydrogen atoms is substituted with a halogen atom, and the fully halogenated alkyl group means that all of the hydrogen atoms are halogen atoms. Means an alkyl group substituted with Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable. That is, the halogenated alkyl group is preferably a fluorinated alkyl group.
The aryl group preferably has 4 to 20 carbon atoms, more preferably 4 to 10 carbon atoms, and most preferably 6 to 10 carbon atoms. As the aryl group, a partially or completely halogenated aryl group is particularly preferable. The partially halogenated aryl group means an aryl group in which a part of hydrogen atoms is substituted with a halogen atom, and the fully halogenated aryl group means that all of the hydrogen atoms are halogen atoms. Means an aryl group substituted with.
R ³¹ is particularly preferably an alkyl group having 1 to 4 carbon atoms having no substituent or a fluorinated alkyl group having 1 to 4 carbon atoms.
As the organic group for R ^32, a linear, branched, or cyclic alkyl group, aryl group, or cyano group is preferable. As the alkyl group and aryl group for R ^32, the same alkyl groups and aryl groups as those described above for R ³¹ can be used.
R ³² is particularly preferably a cyano group, an alkyl group having 1 to 8 carbon atoms having no substituent, or a fluorinated alkyl group having 1 to 8 carbon atoms.

  More preferable examples of the oxime sulfonate-based acid generator include compounds represented by the following general formula (B-2) or (B-3).

［式（Ｂ−２）中、Ｒ^３３は、シアノ基、置換基を有さないアルキル基またはハロゲン化アルキル基である。Ｒ^３４はアリール基である。Ｒ^３５は置換基を有さないアルキル基またはハロゲン化アルキル基である。］

[In Formula (B-2), R ³³ represents a cyano group, an alkyl group having no substituent, or a halogenated alkyl group. R ³⁴ is an aryl group. R ³⁵ represents an alkyl group having no substituent or a halogenated alkyl group. ]

［式（Ｂ−３）中、Ｒ^３６はシアノ基、置換基を有さないアルキル基またはハロゲン化アルキル基である。Ｒ^３７は２または３価の芳香族炭化水素基である。Ｒ^３８は置換基を有さないアルキル基またはハロゲン化アルキル基である。ｐ”は２または３である。］

[In Formula (B-3), R ³⁶ represents a cyano group, an alkyl group having no substituent, or a halogenated alkyl group. R ³⁷ is a divalent or trivalent aromatic hydrocarbon group. ^R38 is an alkyl group having no substituent or a halogenated alkyl group. p ″ is 2 or 3.]

In the general formula (B-2), alkyl or halogenated alkyl group having no substituent group for R ³³ preferably has 1 to 10 carbon atoms, 1 to 8 carbon atoms, more preferably, carbon Numbers 1 to 6 are most preferable.
R ³³ is preferably a halogenated alkyl group, more preferably a fluorinated alkyl group.
The fluorinated alkyl group for R ³³ is preferably such that the hydrogen atom of the alkyl group is 50% or more fluorinated, more preferably 70% or more fluorinated, and 90% or more fluorinated. Particularly preferred.
As the aryl group of R ³⁴ , one hydrogen atom is removed from an aromatic hydrocarbon ring such as a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, an anthryl group, or a phenanthryl group. And a heteroaryl group in which a part of carbon atoms constituting the ring of these groups is substituted with a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom. Among these, a fluorenyl group is preferable.
The aryl group of R ³⁴ may have a substituent such as an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group, or an alkoxy group. The alkyl group or halogenated alkyl group in the substituent preferably has 1 to 8 carbon atoms, and more preferably 1 to 4 carbon atoms. The halogenated alkyl group is preferably a fluorinated alkyl group.
The alkyl group or halogenated alkyl group having no substituent of R ³⁵ preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 6 carbon atoms.
R ³⁵ is preferably a halogenated alkyl group, more preferably a fluorinated alkyl group.
The fluorinated alkyl group for R ³⁵ is preferably such that the hydrogen atom of the alkyl group is 50% or more fluorinated, more preferably 70% or more fluorinated, and 90% or more fluorinated. Particularly preferred is the strength of the acid generated. Most preferably, it is a fully fluorinated alkyl group in which a hydrogen atom is 100% fluorine-substituted.

In the general formula (B-3), the alkyl group or halogenated alkyl group having no substituent for R ³⁶ is the same as the alkyl group or halogenated alkyl group having no substituent for R ^33. Is mentioned.
Examples of the divalent or trivalent aromatic hydrocarbon group for R ³⁷ include groups obtained by further removing one or two hydrogen atoms from the aryl group for R ³⁴ .
Examples of the alkyl group or halogenated alkyl group having no substituent of R ³⁸ include the same alkyl groups or halogenated alkyl groups having no substituent as R ³⁵ described above.
p ″ is preferably 2.

Specific examples of the oxime sulfonate acid generator include α- (p-toluenesulfonyloxyimino) -benzyl cyanide, α- (p-chlorobenzenesulfonyloxyimino) -benzyl cyanide, α- (4-nitrobenzenesulfonyloxy). Imino) -benzylcyanide, α- (4-nitro-2-trifluoromethylbenzenesulfonyloxyimino) -benzylcyanide, α- (benzenesulfonyloxyimino) -4-chlorobenzylcyanide, α- (benzenesulfonyl) Oxyimino) -2,4-dichlorobenzyl cyanide, α- (benzenesulfonyloxyimino) -2,6-dichlorobenzyl cyanide, α- (benzenesulfonyloxyimino) -4-methoxybenzyl cyanide, α- ( 2-Chlorobenzenesulfonyloxyimino) 4-methoxybenzylcyanide, α- (benzenesulfonyloxyimino) -thien-2-ylacetonitrile, α- (4-dodecylbenzenesulfonyloxyimino) -benzylcyanide, α-[(p-toluenesulfonyloxyimino) -4-methoxyphenyl] acetonitrile, α-[(dodecylbenzenesulfonyloxyimino) -4-methoxyphenyl] acetonitrile, α- (tosyloxyimino) -4-thienyl cyanide, α- (methylsulfonyloxyimino) -1-cyclo Pentenyl acetonitrile, α- (methylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (methylsulfonyloxyimino) -1-cycloheptenylacetonitrile, α- (methylsulfonyloxyimino) -1-cyclooctene Acetonitrile, α- (trifluoromethylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) -cyclohexylacetonitrile, α- (ethylsulfonyloxyimino) -ethylacetonitrile, α- (propyl Sulfonyloxyimino) -propylacetonitrile, α- (cyclohexylsulfonyloxyimino) -cyclopentylacetonitrile, α- (cyclohexylsulfonyloxyimino) -cyclohexylacetonitrile, α- (cyclohexylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- ( Ethylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (isopropylsulfonyloxyimino) -1-cyclope N-tenyl acetonitrile, α- (n-butylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (ethylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (isopropylsulfonyloxyimino) -1-cyclohexenylacetonitrile , Α- (n-butylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (methylsulfonyloxyimino) -phenylacetonitrile, α- (methylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (trifluoro Methylsulfonyloxyimino) -phenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (ethylsulfonyloxyimino) -p- Butoxy phenylacetonitrile, alpha-(propylsulfonyl oxyimino)-p-methylphenyl acetonitrile, alpha-like (methylsulfonyloxyimino)-p-bromophenyl acetonitrile.
Also, an oxime sulfonate-based acid generator disclosed in JP-A-9-208554 (paragraphs [0012] to [0014] [chemical formula 18] to [chemical formula 19]), WO 2004 / 074242A2 (pages 65 to 85). The oxime sulfonate acid generators disclosed in Examples 1 to 40) of No. 1 can also be suitably used.
Moreover, the following can be illustrated as a suitable thing.

Among diazomethane acid generators, specific examples of bisalkyl or bisarylsulfonyldiazomethanes include bis (isopropylsulfonyl) diazomethane, bis (p-toluenesulfonyl) diazomethane, bis (1,1-dimethylethylsulfonyl) diazomethane, Examples include bis (cyclohexylsulfonyl) diazomethane, bis (2,4-dimethylphenylsulfonyl) diazomethane, and the like.
Further, diazomethane acid generators disclosed in JP-A-11-035551, JP-A-11-035552, and JP-A-11-035573 can also be suitably used.
Examples of poly (bissulfonyl) diazomethanes include 1,3-bis (phenylsulfonyldiazomethylsulfonyl) propane and 1,4-bis (phenylsulfonyldiazo) disclosed in JP-A-11-322707. Methylsulfonyl) butane, 1,6-bis (phenylsulfonyldiazomethylsulfonyl) hexane, 1,10-bis (phenylsulfonyldiazomethylsulfonyl) decane, 1,2-bis (cyclohexylsulfonyldiazomethylsulfonyl) ethane, 1,3 -Bis (cyclohexylsulfonyldiazomethylsulfonyl) propane, 1,6-bis (cyclohexylsulfonyldiazomethylsulfonyl) hexane, 1,10-bis (cyclohexylsulfonyldiazomethylsulfonyl) decane, etc. Door can be.

(B) As a component, these acid generators may be used individually by 1 type, and may be used in combination of 2 or more type.
In the present invention, it is preferable to use an onium salt acid generator having a fluorinated alkyl sulfonate ion as an anion as the component (B).
The content of the component (B) in the positive resist composition of the present invention is preferably 0.5 to 50 parts by mass and more preferably 1 to 40 parts by mass with respect to 100 parts by mass of the component (A). By setting it within the above range, pattern formation is sufficiently performed. Moreover, since a uniform solution is obtained and storage stability becomes favorable, it is preferable.

<Optional component>
The positive resist composition of the present invention may further contain a nitrogen-containing organic compound (D) (hereinafter referred to as “component (D)”) as an optional component.
The component (D) is not particularly limited as long as it acts as an acid diffusion controller, that is, a quencher that traps the acid generated from the component (B) by exposure, and a wide variety of components have already been proposed. Therefore, any known one may be used, and aliphatic amines, particularly secondary aliphatic amines and tertiary aliphatic amines are particularly preferable. Here, the aliphatic amine is an amine having one or more aliphatic groups, and the aliphatic groups preferably have 1 to 20 carbon atoms.
Examples of the aliphatic amine include an amine (alkylamine or alkyl alcohol amine) or a cyclic amine in which at least one hydrogen atom of ammonia NH ₃ is substituted with an alkyl group or hydroxyalkyl group having 20 or less carbon atoms. .
Specific examples of alkylamines and alkyl alcohol amines include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine; diethylamine, di-n-propylamine, di- -Dialkylamines such as n-heptylamine, di-n-octylamine, dicyclohexylamine; trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-hexylamine, tri-n-pentylamine , Tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decanylamine, tri-n-dodecylamine, and the like; diethanolamine, triethanolamine, diisopropanolamine Triisopropanolamine, di -n- octanol amine, tri -n- octanol amine, stearyl diethanolamine, alkyl alcohol amines such as lauryl diethanolamine. Among these, trialkylamine and / or alkyl alcohol amine are preferable.
Examples of the cyclic amine include heterocyclic compounds containing a nitrogen atom as a hetero atom. The heterocyclic compound may be monocyclic (aliphatic monocyclic amine) or polycyclic (aliphatic polycyclic amine).
Specific examples of the aliphatic monocyclic amine include piperidine and piperazine.
As the aliphatic polycyclic amine, those having 6 to 10 carbon atoms are preferable. Specifically, 1,5-diazabicyclo [4.3.0] -5-nonene, 1,8-diazabicyclo [5. 4.0] -7-undecene, hexamethylenetetramine, 1,4-diazabicyclo [2.2.2] octane, and the like.
Examples of the aromatic amine include aniline, pyridine, 4-dimethylaminopyridine, pyrrole, indole, pyrazole, imidazole or derivatives thereof, diphenylamine, triphenylamine, and tribenzylamine.
Other aliphatic amines include tris (2-methoxymethoxyethyl) amine, tris {2- (2-methoxyethoxy) ethyl} amine, tris {2- (2-methoxyethoxymethoxy) ethyl} amine, tris {2 -(1-methoxyethoxy) ethyl} amine, tris {2- (1-ethoxyethoxy) ethyl} amine, tris {2- (1-ethoxypropoxy) ethyl} amine, tris [2- {2- (2-hydroxy Ethoxy) ethoxy} ethylamine and the like.
These may be used alone or in combination of two or more.
(D) component is normally used in 0.01-5.0 mass parts with respect to 100 mass parts of (A) component. By setting the content in the above range, the resist pattern shape, the stability over time, and the like are improved.

The positive resist composition of the present invention includes, as optional components, organic carboxylic acids, phosphorus oxoacids and derivatives thereof for the purpose of preventing sensitivity deterioration, improving the resist pattern shape, retention stability over time, etc. At least one compound (E) selected from the group consisting of (hereinafter referred to as component (E)) can be contained.
As the organic carboxylic acid, for example, acetic acid, malonic acid, citric acid, malic acid, succinic acid, benzoic acid, salicylic acid and the like are suitable.
Examples of phosphorus oxo acids and derivatives thereof include phosphoric acid, phosphonic acid, phosphinic acid and the like, and among these, phosphonic acid is particularly preferable.
Examples of the oxo acid derivative of phosphorus include esters in which the hydrogen atom of the oxo acid is substituted with a hydrocarbon group, and the hydrocarbon group includes an alkyl group having 1 to 5 carbon atoms and 6 to 6 carbon atoms. 15 aryl groups and the like.
Examples of phosphoric acid derivatives include phosphoric acid esters such as di-n-butyl phosphate and diphenyl phosphate.
Examples of phosphonic acid derivatives include phosphonic acid esters such as phosphonic acid dimethyl ester, phosphonic acid-di-n-butyl ester, phenylphosphonic acid, phosphonic acid diphenyl ester, and phosphonic acid dibenzyl ester.
Examples of phosphinic acid derivatives include phosphinic acid esters such as phenylphosphinic acid.
(E) A component may be used individually by 1 type and may use 2 or more types together.
(E) A component is normally used in 0.01-5.0 mass parts with respect to 100 mass parts of (A) component.

  The positive resist composition of the present invention further contains miscible additives as desired, for example, additional resins for improving the performance of the resist film, surfactants for improving coating properties, dissolution inhibitors, Plasticizers, stabilizers, colorants, antihalation agents, dyes, and the like can be added and contained as appropriate.

The positive resist composition of the present invention can be produced by dissolving the material in an organic solvent (hereinafter sometimes referred to as (S) component).
As the component (S), any component can be used as long as it can dissolve each component to be used to form a uniform solution. Conventionally, any one of known solvents for chemically amplified resists can be used. Two or more types can be appropriately selected and used.
For example, lactones such as γ-butyrolactone;
Ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl-n-pentyl ketone, methyl isopentyl ketone, 2-heptanone;
Polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol;
Compounds having an ester bond such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, dipropylene glycol monoacetate, monomethyl ether, monoethyl ether, monopropyl of the polyhydric alcohols or the compound having an ester bond Derivatives of polyhydric alcohols such as ethers, monoalkyl ethers such as monobutyl ether or compounds having an ether bond such as monophenyl ether [in these, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME) Is preferred];
Cyclic ethers such as dioxane and esters such as methyl lactate, ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate;
Aromatic organic solvents such as anisole, ethyl benzyl ether, cresyl methyl ether, diphenyl ether, dibenzyl ether, phenetol, butyl phenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, cymene, mesitylene, etc. be able to.
These organic solvents may be used independently and may be used as 2 or more types of mixed solvents.
Of these, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), and EL are preferable.
Moreover, the mixed solvent which mixed PGMEA and the polar solvent is also preferable. The blending ratio (mass ratio) may be appropriately determined in consideration of the compatibility between PGMEA and the polar solvent, preferably 1: 9 to 9: 1, more preferably 2: 8 to 8: 2. It is preferable to be within the range.
More specifically, when EL is blended as a polar solvent, the mass ratio of PGMEA: EL is preferably 1: 9 to 9: 1, more preferably 2: 8 to 8: 2. Moreover, when mix | blending PGME as a polar solvent, the mass ratio of PGMEA: PGME becomes like this. Preferably it is 1: 9-9: 1, More preferably, it is 2: 8-8: 2, More preferably, it is 3: 7-7: 3.
In addition, as the component (S), a mixed solvent of at least one selected from PGMEA and EL and γ-butyrolactone is also preferable. In this case, the mixing ratio of the former and the latter is preferably 70:30 to 95: 5.
The amount of component (S) used is not particularly limited, but is a concentration that can be applied to a substrate or the like, and is appropriately set according to the coating film thickness. In general, the solid content concentration of the resist composition is 1 -20% by mass, preferably 2-15% by mass.

≪Resist pattern formation method≫
The resist pattern forming method of the present invention includes a step of forming a resist film on a support using the positive resist composition of the present invention, a step of exposing the resist film, and developing the resist film to form a resist. Forming a pattern.
The resist pattern forming method of the present invention can be performed, for example, as follows.
That is, first, the positive resist composition of the present invention is applied onto a support with a spinner or the like, and pre-baked (post-apply bake (PAB)) for 40 to 120 seconds, preferably at a temperature of 80 to 150 ° C., preferably For 60 to 90 seconds, using an exposure apparatus such as an ArF exposure apparatus, an electron beam drawing apparatus, or an EUV exposure apparatus, exposure through a mask pattern, or drawing by direct irradiation of an electron beam without using a mask pattern, etc. Then, PEB (post-exposure heating) is applied for 40 to 120 seconds, preferably 60 to 90 seconds, at a temperature of 80 to 150 ° C. Subsequently, this is developed using an alkali developer, for example, an aqueous solution of 0.1 to 10% by mass of tetramethylammonium hydroxide (TMAH), preferably rinsed with pure water and dried. In some cases, a baking process (post-bake) may be performed after the development process.
In this way, a resist pattern faithful to the mask pattern can be obtained.

The support is not particularly limited, and a conventionally known one can be used, and examples thereof include a substrate for electronic components and a substrate on which a predetermined wiring pattern is formed. More specifically, a silicon substrate, a metal substrate such as copper, chromium, iron, and aluminum, a glass substrate, and the like can be given. As a material for the wiring pattern, for example, copper, aluminum, nickel, gold or the like can be used.
Further, the support may be a substrate in which an inorganic and / or organic film is provided on the above-described substrate. An inorganic antireflection film (inorganic BARC) is an example of the inorganic film. Examples of the organic film include an organic antireflection film (organic BARC).
The wavelength used for the exposure is not particularly limited, and ArF excimer laser, KrF excimer laser, F ₂ excimer laser, EUV (extreme ultraviolet), VUV (vacuum ultraviolet), EB (electron beam), X-ray, soft X-ray, etc. Can be done using radiation. The resist composition is effective for KrF excimer laser, ArF excimer laser, EB or EUV, and particularly effective for EB or EUV.

The exposure method of the resist film may be normal exposure (dry exposure) performed in an inert gas such as air or nitrogen, or may be immersion exposure (Liquid Immersion Lithography).
In immersion exposure, the space between the resist film and the lens at the lowest position of the exposure apparatus is previously filled with a solvent (immersion medium) having a refractive index larger than that of air, and exposure (immersion exposure) is performed in that state. It is an exposure method.
As the immersion medium, a solvent having a refractive index larger than the refractive index of air and smaller than the refractive index of the resist film to be exposed is preferable. The refractive index of such a solvent is not particularly limited as long as it is within the above range.
Examples of the solvent having a refractive index larger than the refractive index of air and smaller than the refractive index of the resist film include water, a fluorine-based inert liquid, a silicon-based solvent, and a hydrocarbon-based solvent.
Specific examples of the fluorinated inert liquid include fluorinated compounds such as C ₃ HCl ₂ F ₅ , C ₄ F ₉ OCH ₃ , C ₄ F ₉ OC ₂ H ₅ , and C ₅ H ₃ F ₇ as main components. Examples thereof include liquids, and those having a boiling point of 70 to 180 ° C are preferable, and those having a boiling point of 80 to 160 ° C are more preferable. It is preferable that the fluorine-based inert liquid has a boiling point in the above range since the medium used for immersion can be removed by a simple method after the exposure is completed.
As the fluorine-based inert liquid, a perfluoroalkyl compound in which all hydrogen atoms of the alkyl group are substituted with fluorine atoms is particularly preferable. Specific examples of the perfluoroalkyl compound include a perfluoroalkyl ether compound and a perfluoroalkylamine compound.
More specifically, examples of the perfluoroalkyl ether compound include perfluoro (2-butyl-tetrahydrofuran) (boiling point: 102 ° C.). Examples of the perfluoroalkylamine compound include perfluorotributylamine ( Boiling point of 174 ° C.).
As the immersion medium, water is preferably used from the viewpoints of cost, safety, environmental problems, versatility, and the like.

According to the present invention, it is possible to form a resist pattern having a high resolution, a low LWR, and a good shape. Moreover, sensitivity etc. are also favorable. Furthermore, the resist composition of the present invention has high utility for EUV use.
The reason why the above effect is obtained is not clear, but as shown below, the structural unit (a10) has a high carbon density and two structural units (a11) to (a11) having an acid dissociable, dissolution inhibiting group ( This is considered to be due to the interaction of a12).
In a base polymer of a resist composition used in EUV and EB lithography, a structural unit serving as a proton supply source is required to generate secondary electrons and excite an acid generator (T. Kozawa, Y. Yoshida, M. Uesaka, and S. Tagawa: Jpn, J. Appl. Phys. 31 (1992) 4301).
Conventionally, phenol derivatives are frequently used as the structural unit that serves as a proton supply source. In the present invention, by adopting the structural unit (a10) instead of the structural unit of the phenol derivative, the heat resistance of the resist film is improved, contributing to the improvement of the shape and LWR.
For example, in EUV lithography, LWR, shape, and DOF are expected to deteriorate due to the effects of optical and chemical flares (LEE Sang Hun, et. Al, SPIE Vol.5751, No.Pt.1, Page .293-300 (2005)). In order to reduce the influence of flare, it is necessary to suppress the acid diffusion length. In order to suppress the acid diffusion length, it is useful to improve the carbon density and heat resistance of the resist film. The structural unit (a10) has a higher carbon density than the phenol derivative and increases the glass transition temperature (Tg) of the resist film in which the structural unit is formed, thereby improving the heat resistance. By improving the heat resistance, excessive diffusion of acid during exposure and baking is suppressed, and the shape and LWR are improved. Improvement in heat resistance also contributes to improvement in etching resistance.
Among the structural units (a11) to (a12), the structural unit (a12) has an acid dissociable, dissolution inhibiting group at the end of a relatively long side chain. Therefore, the affinity between the long side chain and the component (B) is good, and the uniformity of the distribution of the component (B) in the film is improved, so that the LWR is improved. In addition, the activation energy required for deprotection is low, and the deprotection is easy and contributes to the improvement of resolution and LWR, but the heat resistance is lowered. Although the acid dissociation property of the acid dissociable, dissolution inhibiting group contained in the structural unit (a11) is not as high as that of the structural unit (a12), by combining these structural units (a11) and (a12), resolution, LWR, It became possible to have sufficient characteristics for the shape with high heat resistance and rectangularity. This effect is particularly remarkable when the acid dissociable, dissolution inhibiting group in the structural unit (a11) has a highly hydrophobic ring structure.

In addition, the present inventors used three types of resins, polyhydroxystyrene, poly (1-acryloyloxy-5-hydroxynaphthalene), and poly (2-acryloyloxy-6-hydroxynaphthalene), in the following procedures, respectively. The refractive index (n value) at a wavelength of 633 nm was measured.
A resin solution having a resin concentration of 3% was prepared by dissolving in a mixed solvent of PGMEA / PGME = 6/4 (mass ratio), and this was coated on a 8-inch silicon substrate with a coater (“Clean Track ACT-8”, Tokyo, Japan). Each of which was applied uniformly using Electron Co., Ltd., and baked at 90 ° C. for 60 seconds to form a resin film (film thickness: 100 nm). About this resin film, n value in 633 nm was measured using the spectroscopic ellipsometry VUV-VASE (made by JA WOOLLAM).
As a result, the n values of polyhydroxystyrene, poly (1-acryloyloxy-5-hydroxynaphthalene), and poly (2-acryloyloxy-6-hydroxynaphthalene) were 1.58, 1.63, and 1.63, respectively. It was.
The Onishi parameter generally known as a parameter indicating carbon density is 2.43 for each of polyhydroxystyrene, poly (1-acryloyloxy-5-hydroxynaphthalene) and poly (2-acryloyloxy-6-hydroxynaphthalene). 2.09 and 20.9.
From these results, it was confirmed that the carbon density of the structural unit (a10) was higher than that of the structural unit derived from hydroxystyrene.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited by these examples.
[Polymer synthesis examples 1 to 12]
Under a nitrogen atmosphere, PGMEA was placed in a flask equipped with a nitrogen inlet, a stirrer, a condenser and a thermometer, and the temperature of the hot water bath was raised to 80 ° C. while stirring. Next, a monomer PGMEA solution charged with 2,2′-azobisisobutyronitrile (AIBN) as a polymerization initiator and a monomer mixture having the composition (molar ratio) shown in Table 1 was added using a dropping device. The solution was dropped into the flask at a constant rate for 4 hours, and then kept at 80 ° C. for 2 hours. Thereafter, the reaction solution was returned to room temperature. Subsequently, the obtained reaction solution was added dropwise to about 30 times amount of methanol with stirring to obtain a colorless precipitate. The resulting precipitate was filtered off, and the precipitate was washed in about 30 times the amount of methanol used for the monomer used for the polymerization. The precipitate was filtered off and dissolved in methanol, and then 120 mol% aniline was stirred in the solution at 70 ° C. for 60 hours (deprotection of the acetoxy group was confirmed by proton NMR). After completion of the reaction, the mixture was dropped into a large amount of water to obtain a precipitate. The target polymer compound was obtained by separating the precipitate by filtration, washing, and drying under reduced pressure at 50 ° C. for about 40 hours.
For each polymer compound, the weight average molecular weight (Mw) and dispersity (Mw / Mn) in terms of standard polystyrene determined by GPC measurement are also shown in Table 1.
Further, the copolymer composition ratio (ratio (molar ratio) of each structural unit in the structural formula) was determined by carbon-13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR). The structural formula and copolymer composition ratio of each polymer compound are shown in Table 1.

  Compounds (1) to (4) and structural formulas A-1 to A-6 shown in Table 1 are as follows.

(Examples 1-6, Comparative Examples 1-9)
<Preparation of positive resist composition>
Each component shown in Table 2 was mixed and dissolved to prepare a positive resist composition.

In Table 2, the value in [] is the blending amount (part by mass).
Each abbreviation in Table 2 has the following meaning.
(A) -1: the polymer compound XL.
(A) -2: the polymer compound XH.
(A) -3: the polymer compound YL.
(A) -4: The polymer compound YH.
(A ′)-1: the polymer compound 1H.
(A ′)-2: 1L of the polymer compound.
(A ′)-3: the polymer compound 2H.
(A ′)-4: 4L of the polymer compound.
(A ′)-5: the polymer compound 4M.
(A ′)-6: the polymer compound 4H.
(A ′)-7: 5L of the polymer compound.
(A ′)-8: the polymer compound 5H.
(B) -1: a compound represented by the following chemical formula (B) -1.
(D) -1: tri-n-octylamine.
(S) -1: PGMEA / PGME = 6/4 (mass ratio) mixed solvent.

Each positive resist composition obtained was evaluated as follows.
<Evaluation of lithography properties>
[Evaluation of resist pattern formation]
The positive resist composition of each example was coated on an 8-inch silicon substrate that had been subjected to hexamethyldisilazane (HMDS) treatment at 90 ° C. for 30 seconds, on a coater (“Clean Track ACT-8”, Tokyo Electron Limited). And a baking process (PAB) for 60 seconds at a temperature shown in Table 3 to form a resist film (film thickness 60 nm).
The resist film is drawn (exposure) at an acceleration voltage of 70 keV using an electron beam lithography machine HL-800D (VSB) (manufactured by Hitachi), and subjected to baking treatment (PEB) at a temperature shown in Table 3 for 60 seconds. After further development for 60 seconds using a 2.38 mass% aqueous solution of tetramethylammonium hydroxide (TMAH) (trade name: NMD-3, manufactured by Tokyo Ohka Kogyo Co., Ltd.) at 23 ° C., Rinse with pure water for 15 seconds.
As a result, in each example, a space and line (S / L) pattern having a space width of 100 nm and a pitch of 200 nm was formed.

[Evaluation of sensitivity and resolution]
In the resist pattern formation, the optimum exposure dose Eop (μC / cm ² ) for forming an S / L pattern having a space width of 100 nm and a pitch of 200 nm was determined. The results are shown in Table 3.
Further, the limit resolution (nm) at the Eop was determined. The results are shown in Table 3 as “resolution”.

[LWR evaluation]
With respect to the S / L pattern having a space width of 100 nm and a pitch of 200 nm formed by the above Eop, the line width is measured in the longitudinal direction of the line by a length measuring SEM (scanning electron microscope, trade name: S-9220, manufactured by Hitachi, Ltd.). 5 points were measured, and from the results, a standard deviation (s) three times the value (3 s) was calculated as a measure of LWR. The smaller the value of 3s, the smaller the roughness of the line width, which means that a more uniform width LS pattern was obtained. The results are shown in Table 3.

[Shape evaluation]
The cross-sectional shape of the S / L pattern having a space width of 100 nm and a pitch of 200 nm formed by Eop was observed using a scanning electron microscope (trade name: S-9220, manufactured by Hitachi, Ltd.). Evaluated by criteria. The results are shown in Table 3.
A: The side wall of the line is perpendicular to the substrate surface at the interface with the substrate, and the rectangularity is high.
Δ: The side wall of the line is perpendicular to the substrate surface at the interface with the substrate, but the top portion is slightly round.
X: T-TOP shape and low rectangularity.

As shown in the above results, each of the positive resist compositions of Examples 1 to 6 using the copolymer synthesized using the monomers (4), (2), and (3) has a resolution, Good results were obtained for all evaluations of LWR and shape.
On the other hand, Comparative Examples 1 to 4 using the monomer (1) instead of the monomer (4) and the copolymer synthesized using this and the monomer (2) or (3) have a poor shape and LWR. Was also bad. Further, Comparative Examples 5 to 9 using the copolymer synthesized using the monomer (4) and the monomer (2) or (3) have poor LWR, and in particular, Comparative Examples 7 to 9 have resolution and The shape was also bad.

<Synthesis example of component (B)>
[Synthesis of (B) -1]
35.6 g of compound (I-1) (4-methylphenyldiphenylsulfonium bromide) is dissolved in 360 g of pure water, 360 g of dichloromethane and 38.0 g of compound (I-2) are added thereto, and the mixture is stirred at room temperature for 14 hours. Stir. Thereafter, the dichloromethane layer was separated, washed with dilute hydrochloric acid and water, and the dichloromethane layer was concentrated and dried to obtain the target compound (58 g) as a white solid.

This compound was analyzed by NMR.
¹ H-NMR (DMSO-d6, 400 MHz): δ (ppm) = 1.64 (m, 6H, Ad), 1.82 (m, 6H, Ad), 1.94 (m, 3H, Ad), 3.35 (s, 3H, CH3), 4.55 (t, 2H, CF2CH2), 7.56 (d, 2H, Ar), 7.72-7.84 (m, 12H, Ar).
¹⁹ F-NMR (DMSO-d6, 376 MHz): δ (ppm) = − 111.2.
From the results of the above analysis, it was confirmed that the obtained compound had the structure shown above.

Claims (6)

A positive resist composition comprising a base component (A) whose solubility in an alkaline developer is increased by the action of an acid, and an acid generator component (B) that generates an acid upon exposure,
The base component (A) is a structural unit (a10) represented by the following general formula (a10-1), a structural unit (a11) represented by the following general formula (a11-1), and the following general formula (a12). A positive resist composition comprising the polymer compound (A1) having the structural unit (a12) represented by -1).

[Wherein, R ¹ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, Y ¹ is a single bond or —C (═O) —O—R ²⁰ — (R ²⁰ is a single bond or a divalent linkage) R ² is a single bond or an alkylene group, R ³ is a halogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms, and x is 1 Is an integer of -3, y is an integer of 0-6, x + y is 1-7, R is a hydrogen atom, a C1-C5 alkyl group or a C1-C5 halogenated alkyl group. Yes, X ¹ is an acid dissociable, dissolution inhibiting group, Y ² is a divalent linking group, and X ² is an acid dissociable, dissolution inhibiting group. ] The positive resist composition according to claim 1, wherein the structural unit (a11) is a structural unit represented by the following general formula (a11-11).

[Wherein, R is as defined above, R ²³ is an alkyl group, and R ²⁴ is a group that forms an aliphatic cyclic group together with the carbon atom to which R ²⁴ is bonded. ]   The total proportion of the structural unit (a11) and the structural unit (a12) in the polymer compound (A1) is 15 to 40 mol% with respect to the total of all the structural units constituting the polymer compound (A1). The positive resist composition according to claim 2, which falls within the range.   The ratio (molar ratio) of the structural unit (a11) and the structural unit (a12) in the polymer compound (A1) is in the range of structural unit (a11): structural unit (a12) = 8: 2 to 1: 9. The positive resist composition according to any one of claims 1 to 3, wherein   Furthermore, the positive resist composition as described in any one of Claims 1-4 containing a nitrogen-containing organic compound (D).   A step of forming a resist film using the positive resist composition according to any one of claims 1 to 5, a step of exposing the resist film, and an alkali development of the resist film on a support A resist pattern forming method including a step of forming a resist pattern.