JP2009019028A - Compound, acid generator, resist composition and method for forming resist pattern - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compound suitable as an acid generator for a resist composition, an acid generator composed of the compound and a resist composition containing the acid generator, and to provide a method for forming a resist pattern, using the resist composition. <P>SOLUTION: The compound is represented by general formula (b1-14) (wherein at least one of R<SP>7</SP>"-R<SP>9</SP>" is a substituted aryl group in which a portion or all of the hydrogen atoms are substituted with an alkoxyalkyloxy group or an alkoxycarbonylalkyloxy group or the like; and X<SP>-</SP>is an anion). The acid generator comprises the compound. The resist composition comprises a base component (A) that changes its solubility in an alkali development solution by an acid action and an acid generator component (B) generating an acid by the exposure to light. The acid generator component (B) contains the acid generator (B1) composed of the compound. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a compound suitable as an acid generator for a resist composition, an acid generator comprising the compound, a resist composition containing the acid generator, and a resist pattern forming method using the resist composition.

In lithography technology, for example, a resist film made of a resist material is formed on a substrate, and the resist film is selectively exposed to radiation such as light or an electron beam through a mask on which a predetermined pattern is formed. And a development process is performed to form a resist pattern having a predetermined shape on the resist film. 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 rapidly progressed 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 at present, 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 whose solubility in an alkaline developer is increased by the action of an acid and an acid generator, and from the acid generator by exposure during resist pattern formation. When the acid is generated, the exposed portion becomes alkali-soluble.

Up to now, as the base resin of chemically amplified resist, polyhydroxystyrene (PHS), which is highly transparent to KrF excimer laser (248 nm), and a resin whose hydroxyl group is protected with an acid dissociable, dissolution inhibiting group (PHS resin) Has been used. However, since the PHS resin has an aromatic ring such as a benzene ring, the transparency to light having a wavelength shorter than 248 nm, for example, 193 nm, is not sufficient. Therefore, a chemically amplified resist having a PHS-based resin as a base resin component has drawbacks such as low resolution in a process using 193 nm light, for example.
Therefore, as a resist base resin currently used in ArF excimer laser lithography and the like, it has a structural unit generally derived from a (meth) acrylic acid ester in its main chain because of its excellent transparency near 193 nm. Resin (acrylic resin) is used. In the case of the positive type, the resin includes a structural unit derived from a (meth) acrylic acid ester containing a tertiary alkyl ester type acid dissociable, dissolution inhibiting group containing an aliphatic polycyclic group, for example, 2-alkyl. A resin having a structural unit derived from 2-adamantyl (meth) acrylate or the like is mainly used (for example, see Patent Document 1).

  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. “(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. “(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.

On the other hand, various acid generators used in chemically amplified resists have been proposed so far, such as onium salt acid generators such as iodonium salts and sulfonium salts, oxime sulfonate acid generators, Diazomethane acid generators, nitrobenzyl sulfonate acid generators, imino sulfonate acid generators, disulfone acid generators and the like are known. Currently, an acid generator containing a triphenylsulfonium skeleton, a dinaphthyl monophenylsulfonium skeleton, or the like is used as an acid generator (Patent Document 2).
JP 2003-241385 A Japanese Patent Laid-Open No. 2005-37888

In recent years, the miniaturization of resist patterns has further progressed, and as the demand for high resolution has further increased, improvements in various lithography properties have been demanded.
For example, the improvement of the pattern shape and mask reproducibility when a resist pattern is formed becomes more important as the pattern becomes finer. The mask error factor (MEF) is one of the indexes indicating such characteristics, and the mask size (line width in a line-and-space pattern or hole diameter in a contact hole pattern with the same exposure amount and a fixed pitch). ) Is a parameter indicating how faithfully mask patterns of different sizes can be reproduced (mask reproducibility). Improvement of such pattern shape and MEF is important for the improvement of lithography properties, and it is considered that this purpose can be achieved by using a novel acid generator.
The present invention has been made in view of the above circumstances, and is a novel compound suitable as an acid generator for a resist composition, an acid generator comprising the compound, a resist composition containing the acid generator, and the An object of the present invention is to provide a resist pattern forming method using a resist composition.

  The 1st aspect of this invention which solves the said subject is a compound represented by the following general formula (b1-14).

［式中、Ｒ^７”〜Ｒ^９”は、それぞれ独立に、アリール基またはアルキル基を表し；Ｒ^７”〜Ｒ^９”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^７”〜Ｒ^９”のうち少なくとも１つは、水素原子の一部または全部がアルコキシアルキルオキシ基またはアルコキシカルボニルアルキルオキシ基で置換された置換アリール基であり；Ｘ⁻はアニオンである。］

[Wherein, R ⁷ ″ to R ⁹ ″ each independently represents an aryl group or an alkyl group; any two of R ⁷ ″ to R ⁹ ″ are bonded to each other to form a sulfur atom in the formula May form a ring; at least one of R ⁷ ″ to R ⁹ ″ is a substituted aryl group in which part or all of the hydrogen atoms are substituted with an alkoxyalkyloxy group or an alkoxycarbonylalkyloxy group; X ⁻ is an anion. ]

  Moreover, the 2nd aspect of this invention is an acid generator which consists of a compound represented by the said general formula (b1-14).

  Furthermore, the third aspect of the present invention is a resist composition containing a base component (A) whose solubility in an alkaline developer is changed by the action of an acid and an acid generator component (B) that generates an acid upon exposure. And the said acid generator component (B) is a resist composition characterized by including the acid generator (B1) which consists of a compound represented by the said general formula (b1-14).

  Furthermore, the fourth aspect of the present invention includes a step of forming a resist film on a support using the resist composition of the third aspect of the present invention, a step of exposing the resist film, and the resist film. Is a resist pattern forming method including a step of forming a resist pattern by alkali development.

In the present specification and claims, “structural unit” means a monomer unit (monomer unit) constituting a resin component (polymer).
“Exposure” is a concept that includes radiation exposure in general.
Unless otherwise specified, the “alkyl group” includes linear, branched and cyclic monovalent saturated hydrocarbon groups.
The “lower alkyl group” means an alkyl group having 1 to 5 carbon atoms.
An “acid-dissociable group” is an organic group that can be dissociated by the action of an acid.

  According to the present invention, there are provided a novel compound suitable as an acid generator for a resist composition, an acid generator comprising the compound, a resist composition containing the acid generator, and a resist pattern forming method using the resist composition. Provided.

Hereinafter, the present invention will be described in more detail.
≪Compound≫
The compound of the first aspect of the present invention is represented by the general formula (b1-14).
In the general formula (b1-14), R ⁷ ″ to R ⁹ ″ each independently represents an aryl group or an alkyl group. However, at least one of R ⁷ ″ to R ⁹ ″ is a substituted aryl group in which part or all of the hydrogen atoms are substituted with an alkoxyalkyloxy group or an alkoxycarbonylalkyloxy group.
The aryl group for R ⁷ ″ to R ⁹ ″ is not particularly limited, and is, for example, an aryl group having 6 to 20 carbon atoms, in which part or all of the hydrogen atoms are alkoxyalkyloxy A substituent other than the group and the alkoxycarbonylalkyloxy group, for example, an alkyl group, an alkoxy group, a halogen atom, a hydroxyl group and the like may or may not be substituted. Such an 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 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, an ethyl group, a propyl group, an n-butyl group, or a 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, Most preferred is a tert-butoxy group.
The halogen atom that may substitute the hydrogen atom of the aryl group is preferably a fluorine atom.
There is no restriction | limiting in particular as an alkyl group of R < ⁷ >''-R< ⁹ >'', For example, a C1-C10 linear, branched or cyclic alkyl group etc. are mentioned. 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.

At least one of R ⁷ ″ to R ⁹ ″ is a substituted aryl group in which part or all of the hydrogen atoms of the aryl group are substituted with an alkoxyalkyloxy group or an alkoxycarbonylalkyloxy group. R 7 ^{"~R 9"} 2 or more of the may be the substituted aryl group, but is most preferably any one of R 7 ^{"~R 9"} is the substituted aryl group.

  Examples of the alkoxyalkyloxy group in which a hydrogen atom is substituted in the substituted aryl group include those represented by the following general formula (b14-1).

［式中、Ｒ^４７およびＲ^４８はそれぞれ独立して水素原子または直鎖状もしくは分岐鎖状のアルキル基であり、Ｒ^４９はアルキル基であり、Ｒ^４８およびＲ^４９は相互に結合して一つの環構造を形成していても良い。ただし、Ｒ^４７およびＲ^４８のうち少なくとも１つは水素原子である。］

[Wherein, R ⁴⁷ and R ⁴⁸ are each independently a hydrogen atom or a linear or branched alkyl group, R ⁴⁹ is an alkyl group, and R ⁴⁸ and R ⁴⁹ are bonded to each other. Two ring structures may be formed. However, at least one of R ⁴⁷ and R ⁴⁸ is a hydrogen atom. ]

In the formula, R ⁴⁷ and R ⁴⁸ are each independently a hydrogen atom or a linear or branched alkyl group, provided that at least one of R ⁴⁷ and R ⁴⁸ is a hydrogen atom.
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, a 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, a cyclic group is formed by R ⁴⁸ , R ⁴⁹ , the oxygen atom to which R ⁴⁹ is bonded, and the carbon atom to which 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.

  Examples of the alkoxycarbonylalkyloxy group in which a hydrogen atom is substituted in the substituted aryl group include those represented by the following general formula (b14-2).

［式中、Ｒ^５０は直鎖状もしくは分岐鎖状のアルキレン基であり、Ｒ^５１は酸解離性基である。］

[Wherein, R ⁵⁰ is a linear or branched alkylene group, and R ⁵¹ is an acid dissociable group. ]

The linear or branched alkylene group for R ⁵⁰ preferably has 1 to 5 carbon atoms, such as a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, or a 1,1-dimethylethylene group. Etc.
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, but is a cyclic or chain tertiary alkyl ester type acid dissociable group; Examples include acid dissociable groups, and among these, tertiary alkyl ester type acid dissociable groups are preferable. Specifically, 2-methyl-2-adamantyl group, 2-ethyl-2-adamantyl group, 1-methyl-1-cyclopentyl group, 1-ethyl-1-cyclopentyl group, 1-methyl-1-cyclohexyl group, 1-ethyl-1-cyclohexyl group, 1- (1-adamantyl) -1-methylethyl group, 1- (1-adamantyl) -1-methylpropyl group, 1- (1-adamantyl) -1-methylbutyl group, 1- (1-adamantyl) -1-methylpentyl group; 1- (1-cyclopentyl) -1-methylethyl group, 1- (1-cyclopentyl) -1-methylpropyl group, 1- (1-cyclopentyl)- 1-methylbutyl group, 1- (1-cyclopentyl) -1-methylpentyl group; 1- (1-cyclohexyl) -1-methylethyl group, 1- (1-cyclohexyl) ) -1-methylpropyl group, 1- (1-cyclohexyl) -1-methylbutyl group, 1- (1-cyclohexyl) -1-methylpentyl group, tert-butyl group, tert-pentyl group, tert-hexyl group, etc. Is mentioned.

  In the substituted aryl group, the number of alkoxyalkyloxy groups or alkoxycarbonylalkyloxy groups substituted with hydrogen atoms is preferably 2 or less, and most preferably 1.

R ⁷ ″ to R ⁹ ″ other than the substituted aryl group are each preferably a phenyl group or a naphthyl group, and most preferably a phenyl group.

Any two of R ⁷ ″ to R ⁹ ″ may be bonded to each other to form a ring together with the sulfur atom in the formula. In this case, it is preferable to form a 3- to 10-membered ring including a sulfur atom, and it is particularly preferable to form a 5- to 7-membered ring.

In the general formula (b1-14), X ⁻ represents an anion. The anion moiety of X ⁻ is not particularly limited, and any known anion moiety of the onium salt acid generator can be used as appropriate. For example, an anion represented by the general formula “R ¹⁴ SO ₃ ^— (R ¹⁴ represents a linear, branched or cyclic alkyl group, halogenated alkyl group, aryl group, or alkenyl group)”, Or the general formula “R ¹ —O—Y ¹ —SO ₃ ^— (R ¹ is a monovalent aliphatic hydrocarbon group, monovalent aromatic organic group, or hydroxyalkyl group; Y ¹ is fluorine-substituted; And an anion represented by the above-mentioned alkylene group having 1 to 4 carbon atoms may be used.

In the general formula “R ¹⁴ SO ₃ ⁻ ”, R ¹⁴ represents a linear, branched or cyclic alkyl group, a halogenated alkyl group, an aryl group, or an alkenyl group.
The linear or branched alkyl group as R ¹⁴ preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and 1 to 4 carbon atoms. Most preferred.
The cyclic alkyl group as R ¹⁴ preferably has 4 to 15 carbon atoms, more preferably 4 to 10 carbon atoms, and most preferably 6 to 10 carbon atoms.
The halogenated alkyl group as R ¹⁴ is a group in which part or all of the hydrogen atoms in the alkyl group are substituted with halogen atoms, and the alkyl group is preferably a lower alkyl group having 1 to 5 carbon atoms, Among these, a linear or branched alkyl group is more preferable, and it is a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a tert-butyl group, a tert-pentyl group, or an isopentyl group. Further preferred. And the halogen atom by which a hydrogen atom is substituted includes a fluorine atom, a chlorine atom, an iodine atom, a bromine atom and the like. In the halogenated alkyl group, it is desirable that 50 to 100% of the total number of hydrogen atoms are substituted with halogen atoms, and it is more preferable that all are substituted.
Here, the halogenated alkyl group is preferably a fluorinated alkyl group. The fluorinated 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 fluorination rate of the fluorinated alkyl group (ratio of the number of fluorine atoms substituted by fluorination to the total number of hydrogen atoms in the alkyl group before fluorination, the same shall apply hereinafter) is preferably 10 to 100%. More preferably, it is 50 to 100%, and in particular, those in which all hydrogen atoms are substituted with fluorine atoms are preferred because the strength of the acid becomes strong. Specific examples of such a preferred fluorinated alkyl group include a trifluoromethyl group, a heptafluoro-n-propyl group, and a nonafluoro-n-butyl group.
The aryl group as R ¹⁴ is preferably an aryl group having 6 to 20 carbon atoms which may have a substituent. Examples of the substituent that may have include a halogen atom, a hetero atom, and an alkyl group. You may have multiple substituents.
The alkenyl group as R ¹⁴ is preferably an alkenyl group having 2 to 10 carbon atoms which may have a substituent. Examples of the substituent that may have include a halogen atom, a hetero atom, and an alkyl group. You may have multiple substituents.
Among these, as R ¹⁴ , a halogenated alkyl group is preferable.

In the general formula “R ¹ —O—Y ¹ —SO ₃ ^— ”, R ¹ is a monovalent aliphatic hydrocarbon group, aromatic organic group, or hydroxyalkyl group; and Y ¹ is fluorine-substituted. Or an alkylene group having 1 to 4 carbon atoms.

Examples of the monovalent aliphatic hydrocarbon group for R ¹ include a linear, branched or cyclic monovalent saturated hydrocarbon group having 1 to 15 carbon atoms, or a linear chain having 2 to 5 carbon atoms. And a monovalent aliphatic unsaturated hydrocarbon group having a chain shape or a branched chain.

Examples of the linear monovalent saturated hydrocarbon group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, and a decanyl group.
Examples of the branched monovalent saturated hydrocarbon group include 1-methylethyl group, 1-methylpropyl group, 2-methylpropyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, 1 -Ethylbutyl group, 2-ethylbutyl group, 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group and the like can be mentioned.
The cyclic monovalent saturated hydrocarbon group may be either a polycyclic group or a monocyclic group, for example, one from a polycycloalkane such as a monocycloalkane, a bicycloalkane, a tricycloalkane, or a tetracycloalkane. And a group in which a hydrogen atom is removed. More specifically, one hydrogen atom was removed from a monocycloalkane such as cyclopentane, cyclohexane, cycloheptane, and cyclooctane, and a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Groups and the like.
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.
The number of carbon atoms of the monovalent aliphatic hydrocarbon group R ¹ is 2 to 4 and most preferably 3.

Examples of the monovalent aromatic organic group for R ¹ include hydrogen 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. An aryl group in which one atom is removed; a heteroaryl group in which a part of carbon atoms constituting the ring of these aryl groups is substituted with a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom; a benzyl group, a phenethyl group, Examples thereof include arylalkyl groups such as 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group and 2-naphthylethyl group. The alkyl chain in the arylalkyl group preferably has 1 to 4 carbon atoms, more preferably 1 to 2, and particularly preferably 1. These aryl group, heteroaryl group, and arylalkyl group may have a substituent such as an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group, an alkoxy group, a hydroxyl group, or a halogen atom. 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. Examples of the halogen atom include a fluorine atom, a chlorine atom, an iodine atom, and a bromine atom, and a fluorine atom is preferable.

The hydroxyalkyl group of R ¹ is a group in which at least one hydrogen atom of a linear, branched or cyclic monovalent saturated hydrocarbon group is substituted with a hydroxyl group. Those in which one or two hydrogen atoms of a linear or branched monovalent saturated hydrocarbon group are substituted with a hydroxyl group are preferred. Specific examples include a hydroxymethyl group, a hydroxyethyl group, a 1-hydroxypropyl group, a 2-hydroxypropyl group, a 3-hydroxypropyl group, and a 2,3-dihydroxypropyl group.
R The number of carbon atoms of the monovalent hydroxyalkyl group having ¹ preferably 1 to 10, more preferably 1 to 8, particularly preferably 1 to 6, 1 to 3 is most preferred.

Examples of the alkylene group having 1 to 4 carbon atoms which may be fluorine-substituted for Y ¹ include —CF ₂ —, —CF ₂ CF ₂ —, —CF ₂ CF ₂ CF ₂ —, and —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 -, - CH 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.

Further, the Y ^1, the fluorine substituents on these alkylene group having 1 to 4 carbon atoms, it is preferred that the carbon atom bonded to S is fluorinated, as such a 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 -} ; etc. Ageruko the Can.
Of _{these, -CF 2 CF 2 -, -} CF 2 CF 2 CF 2 -, or _CH 2 _CF 2 CF ₂ - is preferable, _-CF 2 CF ₂ - or _-CF 2 _CF 2 CF ₂ - is more preferable, -CF ₂ CF ₂ - is particularly preferred.

In the general formula (b1-14), X ⁻ may be an anion represented by the following general formula (b-3), an anion represented by the following general formula (b-4), or the like.

[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 a C 1-10 alkyl group substituted with

In the general formula (b-3), 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 preferably has 2 carbon atoms. -6, more preferably 3-5 carbon atoms, most preferably 3 carbon atoms.
In the general formula (b-4), Y ″ and Z ″ each independently represent a linear or branched alkyl group in which at least one hydrogen atom is substituted with a fluorine atom. Carbon number becomes like this. Preferably it is 1-10, More preferably, it is C1-C7, Most preferably, it is C1-C3.
The number of carbon atoms of the alkylene group of X ″ or the number of carbon atoms of the alkyl group of Y ″ and Z ″ is preferably as small as possible within the range of the above carbon number for reasons such as good solubility in a resist solvent.
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 by fluorine atoms increases, and high-energy light or electron beam of 200 nm or less The fluorination rate of the alkylene group or alkyl group is preferably 70 to 100%, more preferably 90 to 100%, and most preferably all hydrogen atoms are fluorine atoms. A substituted perfluoroalkylene group or a perfluoroalkyl group.

In the general formula (b1-14), X ⁻ may be a halogen anion. Here, examples of the halogen anion include fluoride ion, chloride ion, bromide ion, and iodide ion.

  Preferred specific examples of the compound of the first aspect of the present invention are given below.

  Among these, the compounds represented by the chemical formulas (b1-14-101), (b1-14-201), (b1-14-301), (b1-14-401) and (b1-14-402) Is preferred.

<Method for producing compound>
The compound (b1-14) of the first aspect of the present invention can be produced, for example, as follows. That is, the following general formulas (b1-14-01) and (b1-14) are contained in a solution of an organic acid H ⁺ B ⁻ (B ⁻ represents an anion part of an organic acid such as a methanesulfonate ion). −02) and the reaction is carried out, and then pure water and an organic solvent (for example, dichloromethane, tetrahydrofuran, etc.) are added to recover the organic layer. From the organic layer, the following general formula (b1- 14-03) is obtained.
Next, the compound represented by the general formula (b1-14-03) is dissolved in a mixed solvent of an organic solvent (for example, dichloromethane, tetrahydrofuran, etc.) and water, and an alkali metal salt of a desired anion X ⁻ is dissolved therein. L ⁺ X ⁻ (L ⁺ represents an alkali metal cation such as lithium ion, potassium ion, sodium ion, etc.) is added and reacted, followed by liquid separation and washing with water, and from the organic layer, the following general formula (b1 The compound represented by -14-04) is obtained.
Next, the compound represented by the general formula (b1-14-04) is dissolved in an organic solvent (for example, dichloromethane, tetrahydrofuran and the like), ice-cooled, a base (for example, sodium hydride and the like) is added, and the desired compound is added. A halide of an alkoxyalkyl group or an alkoxycarbonylalkyl group (for example, a general formula “Cl—C (R ⁴⁷ ) (R ⁴⁸ ) —O—R ⁴⁹ ”, “Cl—R ⁵⁰ —C (═O) —O—R) ⁵¹ ”,“ Br—R ⁵⁰ —C (═O) —O—R ⁵¹ ”, etc., wherein R ^{47 to} R ⁵¹ are the same as described above), and —OH of —R ¹⁰ ″ —OH A compound (b1-14) is obtained by substituting the hydrogen atom of the group with the alkoxyalkyl group or alkoxycarbonylalkyl group.

［式中、Ｒ^８”およびＲ^９”は前記一般式（ｂ１−１４）中のＲ^８”およびＲ^９”と同様であり；Ｒ^１０”は前記一般式（ｂ１−１４）中のアリール基であるＲ^７”から１つの水素原子を除いたアリーレン基であり；Ｂ⁻は、有機酸のアニオン部であり；Ｌ^＋は、アルカリ金属カチオンであり；Ｘ⁻は、前記一般式（ｂ１−１４）中のＸ⁻と同様である。］
また、化合物（ｂ１−１４−０３）のアニオン交換について、Ｌ^＋Ｘ⁻と反応させる前に化合物（ｂ１−１４−０３）の−Ｒ^１０” −ＯＨの−ＯＨ基の水素原子を前記アルコキシアルキル基またはアルコキシカルボニルアルキル基と置換してから、アニオン交換を行うことによっても、化合物（ｂ１−１４）を得ることができる。

Wherein, ^{R 8} "and ^{R 9"} is the same as ^{R 8} "and ^{R 9"} in the general formula ^{(b1-14); R 10} "is an aryl group in the general formula (b1-14) R ⁷ ″ is an arylene group obtained by removing one hydrogen atom; B ⁻ is an anion portion of an organic acid; L ⁺ is an alkali metal cation; and X ⁻ is the general formula (b1- 14) in the X ^- it is the same as. ]
In addition, regarding the anion exchange of the compound (b1-14-03), the hydrogen atom of the —OH group of —R ¹⁰ ″ —OH of the compound (b1-14-03) is substituted with the alkoxyalkyl before reacting with L ⁺ X ^—. The compound (b1-14) can also be obtained by performing anion exchange after substitution with a group or an alkoxycarbonylalkyl group.

≪Acid generator≫
The acid generator of the second aspect of the present invention (hereinafter sometimes referred to as an acid generator (B1)) is composed of a compound represented by the general formula (b1-14). In the formula, R ⁷ ″ to R ⁹ ″ and X ⁻ are the same as those described in the compound of the first aspect of the present invention.

≪Resist composition≫
The resist composition according to the third aspect of the present invention comprises a base component (A) whose solubility in an alkaline developer is changed by the action of an acid (hereinafter referred to as component (A)) and an acid that generates an acid upon exposure. It contains a generator component (B) (hereinafter referred to as component (B)), and the component (B) contains an acid generator (B1) composed of a compound represented by the general formula (b1-14). It is a waste.

In the resist composition of the present invention, as the component (A), a polymer material whose solubility in an alkali developer is changed by the action of an acid can be used, and the solubility in an alkali developer is changed by the action of an acid. Low molecular weight materials can also be used.
The resist composition of the present invention may be a negative resist composition or a positive resist composition.
When the resist composition of the present invention is a negative resist composition, for example, the component (A) is an alkali-soluble resin, and a crosslinking agent (C) is further blended in the negative resist composition.
In such a negative resist composition, when an acid is generated from the component (B) by exposure at the time of resist pattern formation, the exposed portion acts to cause crosslinking between the alkali-soluble resin and the crosslinking agent. Change to insoluble.
As the alkali-soluble resin, a resin having a unit derived from at least one selected from α- (hydroxyalkyl) acrylic acid or a lower alkyl ester of α- (hydroxyalkyl) acrylic acid is a good resist with little swelling. A pattern can be formed, which is preferable. Note that α- (hydroxyalkyl) acrylic acid includes acrylic acid in which a hydrogen atom is bonded to the α-position carbon atom to which the carboxy group is bonded, and a hydroxyalkyl group (preferably having 1 carbon atom) in the α-position carbon atom. One or both of [alpha] -hydroxyalkylacrylic acids to which (5) hydroxyalkyl groups) are attached.
As the crosslinking agent (C), for example, it is usually preferable to use an amino crosslinking agent such as glycoluril having a methylol group or an alkoxymethyl group because a good resist pattern with little swelling can be formed. It is preferable that the compounding quantity of a crosslinking agent (C) is 1-50 mass parts with respect to 100 mass parts of alkali-soluble resin.

  When the resist composition of the present invention is a positive resist composition, the component (A) is insoluble in an alkali developer before exposure, and is generated from the component (B) by exposure at the time of resist pattern formation. When the acid acts, the acid dissociable, dissolution inhibiting group is dissociated, thereby increasing the solubility of the entire component (A) in the alkali developer, and changing from alkali-insoluble to alkali-soluble. Therefore, in the formation of the resist pattern, when the resist film obtained by applying the positive resist composition on the substrate is selectively exposed, the exposed portion turns into alkali-soluble while the unexposed portion is alkali-insoluble. Since it remains unchanged, alkali development can be performed.

  In the resist composition of the present invention, the component (A) is preferably a base material component whose solubility in an alkaline developer is increased by the action of an acid. That is, the resist composition of the present invention is preferably a positive resist composition. The component (A) is more preferably a resin component (A1) whose alkali solubility is increased by the action of an acid (hereinafter referred to as (A1) component).

<(A1) component>
The component (A1) suitably used in such a positive resist composition preferably has a structural unit (a1) derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group.
The component (A1) preferably further has a structural unit (a2) derived from an acrylate ester containing a lactone-containing cyclic group.
The component (A1) preferably further has a structural unit (a3) derived from an acrylate ester containing a polar group-containing aliphatic hydrocarbon group.

Here, in the present specification and claims, 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 a lower alkyl group and a halogenated lower 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.
In the acrylate ester, as the lower alkyl group as a substituent at the α-position, specifically, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, pentyl group, Examples include linear or branched lower alkyl groups such as isopentyl group and neopentyl group.
Specific examples of the halogenated lower alkyl group include groups in which part or all of the hydrogen atoms in the above-mentioned “lower alkyl group as a substituent at the α-position” are substituted with halogen atoms. Here, 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 present invention, the α-position of the acrylate ester is preferably a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, and is a hydrogen atom, a lower alkyl group or a fluorinated lower alkyl group. In view of industrial availability, a hydrogen atom or a methyl group is particularly preferable.

・ Structural unit (a1)
The structural unit (a1) is a structural unit derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group.
The acid dissociable, dissolution inhibiting group in the structural unit (a1) has an alkali dissolution inhibiting property that makes the entire component (A1) difficult to dissolve in an alkali developer before dissociation, and dissociates with an acid. This increases the solubility of the entire component in an alkaline developer, and those that have been proposed as acid dissociable, dissolution inhibiting groups for base resins for chemically amplified resists 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” in the claims and the specification is a relative concept with respect to aromatics, and is defined to mean a group, a compound, or the like that does not have aromaticity.
“Aliphatic branched” means having a branched structure having no 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.
As the aliphatic branched acid dissociable, dissolution inhibiting group, a tertiary alkyl group having 4 to 8 carbon atoms is preferable, and specific examples include a tert-butyl group, a tert-pentyl group, and a tert-heptyl group. .

The “aliphatic cyclic group” means a monocyclic group or a polycyclic group having no aromaticity.
The “aliphatic cyclic group” in the structural unit (a1) may or may not have a substituent. Examples of the substituent include a lower alkyl group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated lower alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, an oxygen atom (= O), and the like.
The basic ring structure excluding the substituent of the “aliphatic cyclic 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. The “aliphatic cyclic group” is preferably a polycyclic group.
Examples of the aliphatic cyclic group include monocycloalkanes, bicycloalkanes, tricycloalkanes, tetracycloalkanes which may or may not be substituted with a lower alkyl group, a fluorine atom or a fluorinated alkyl group. And groups obtained by removing one or more hydrogen atoms from a polycycloalkane. Specific examples thereof 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.

  Examples of the acid dissociable, dissolution inhibiting group containing an aliphatic cyclic group include a group having a tertiary carbon atom on the ring skeleton of a cyclic alkyl group. Specifically, 2-methyl-2 -Adamantyl group, 2-ethyl-2-adamantyl group, etc. are mentioned. Alternatively, in the structural units represented by the following general formulas (a1 ″ -1) to (a1 ″ -6), an adamantyl group such as a group bonded to an oxygen atom of a carbonyloxy group (—C (O) —O—) An aliphatic cyclic group such as a cyclohexyl group, a cyclopentyl group, a norbornyl group, a tricyclodecanyl group, or a tetracyclododecanyl group, and a branched alkylene group having a tertiary carbon atom bonded thereto. Groups.

［式中、Ｒは水素原子、低級アルキル基またはハロゲン化低級アルキル基を示し；Ｒ^１５、Ｒ^１６はアルキル基（直鎖状、分岐鎖状のいずれでもよく、好ましくは炭素数１〜５である）を示す。］

[Wherein, R represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group; R ¹⁵ and R ¹⁶ may be alkyl groups (both linear and branched, preferably 1 to 5 carbon atoms). Is). ]

  In the general formulas (a1 ″ -1) to (a1 ″ -6), the lower alkyl group or halogenated lower alkyl group of R is a lower alkyl group or halogenated lower alkyl which may be bonded to the α-position of the acrylate ester. It is the same as the 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, this 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低級アルキル基を表し、ｎは０〜３の整数を表し、Ｙは低級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 a lower alkyl group, n represents an integer of 0 to 3, and Y represents a lower alkyl group or an aliphatic cyclic group. ]

In the above formula, n is preferably an integer of 0 to 2, more preferably 0 or 1, and most preferably 0.
Examples of the lower alkyl group for R ¹ ′ and R ² ′ include the same lower 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は上記と同様である。］

Wherein, ^{R 1} ', n, Y are as defined above. ]

Examples of the lower alkyl group for Y include the same lower 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 that have been proposed in a number of conventional ArF resists. 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また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、分岐鎖状また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また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 represent 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, and tetracycloalkane, which may or may not be substituted with a fluorine atom or a fluorinated alkyl group, are included. Examples include groups excluding hydrogen atoms. Specific examples thereof 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, 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 end of R ^{19 and} the end of R ¹⁷ And may be combined.
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.

  As the structural unit (a1), one or more selected from the group consisting of structural units represented by the following general formula (a1-0-1) and structural units represented by the following general formula (a1-0-2): Is preferably used.

［式中、Ｒは水素原子、低級アルキル基またはハロゲン化低級アルキル基を示し；Ｘ^１は酸解離性溶解抑制基を示す。］

[Wherein, R represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group; and X ¹ represents an acid dissociable, dissolution inhibiting group. ]

［式中、Ｒは水素原子、低級アルキル基またはハロゲン化低級アルキル基を示し；Ｘ^２は酸解離性溶解抑制基を示し；Ｙ^２はアルキレン基または脂肪族環式基を示す。］

[Wherein, R represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group; X ² represents an acid dissociable, dissolution inhibiting group; Y ² represents an alkylene group or an aliphatic cyclic group. ]

In general formula (a1-0-1), the lower alkyl group or halogenated lower alkyl group for R is the same as the lower alkyl group or halogenated lower alkyl group that may be bonded to the α-position of the acrylate ester. .
X ¹ is not particularly limited as long as it is an acid dissociable, dissolution inhibiting group, and examples thereof include the above-described tertiary alkyl ester type acid dissociable, dissolution inhibiting group and acetal type acid dissociable, dissolution inhibiting group. A tertiary alkyl ester type acid dissociable, dissolution inhibiting group is preferred.

In general formula (a1-0-2), R is the same as defined above.
X ² is the same as X ¹ in formula (a1-0-1).
Y ² is preferably an alkylene group having 1 to 10 carbon atoms or a divalent aliphatic cyclic group, and the aliphatic cyclic group is the above except that a group in which two or more hydrogen atoms are removed is used. The thing similar to description of an "aliphatic cyclic group" can be used.

  More specifically, examples of the structural unit (a1) include structural units represented by the following general formulas (a1-1) to (a1-4).

［上記式中、Ｘ’は第３級アルキルエステル型酸解離性溶解抑制基を表し、Ｙは炭素数１〜５の低級アルキル基、または脂肪族環式基を表し；ｎは０〜３の整数を表わし；Ｙ^２はアルキレン基または脂肪族環式基を表し；Ｒは前記と同じであり、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の低級アルキル基を表す。］

[In the above formula, X ′ represents a tertiary alkyl ester type acid dissociable, dissolution inhibiting group, Y represents a lower alkyl group having 1 to 5 carbon atoms, or an aliphatic cyclic group; Y ² represents an alkylene group or an aliphatic cyclic group; R is the same as defined above; R ¹ ′ and R ² ′ each independently represent a hydrogen atom or a lower alkyl group having 1 to 5 carbon atoms; Represents. ]

At least one of R ¹ ′ and R ² ′ is preferably a hydrogen atom, more preferably a hydrogen atom. n is preferably 0 or 1.

X ′ is the same as the tertiary alkyl ester type acid dissociable, dissolution inhibiting group exemplified in X ¹ above.
Examples of the aliphatic cyclic group for Y include the same groups as those exemplified above in the description of “aliphatic cyclic group”.
Y ² is preferably an alkylene group having 1 to 10 carbon atoms or a divalent aliphatic cyclic group, except that a group in which two or more hydrogen atoms are removed is used as the aliphatic cyclic group. The same as described for the “aliphatic cyclic group” can be used. When Y ² is an alkylene group having 1 to 10 carbon atoms, it is more preferably 1 to 6 carbon atoms, particularly preferably 1 to 4 carbon atoms, and most preferably 1 to 3 carbon atoms. . When Y ² is a divalent aliphatic cyclic group, a group in which two or more hydrogen atoms have been removed from cyclopentane, cyclohexane, norbornane, isobornane, adamantane, tricyclodecane, or tetracyclododecane is particularly preferable. .

  Specific examples of the structural units represented by the general formulas (a1-1) to (a1-4) are shown below.

As the structural unit (a1), one type may be used alone, or two or more types may be used in combination.
Among these, the structural unit represented by the general formula (a1-1) is preferable, and specifically, (a1-1-1) to (a1-1-6) and (a1-1-35) to (a1- It is more preferable to use at least one selected from the group consisting of 1-41).
Furthermore, as the structural unit (a1), in particular, those represented by the following general formula (a1-1-01) including the structural units of the formula (a1-1-1) to the formula (a1-1-4) The following general formula (a1-1-02) including the structural units of formulas (a1-1-35) to (a1-1-41) is also preferable.

［式中、Ｒは水素原子、低級アルキル基またはハロゲン化低級アルキル基を示し、Ｒ^１１は低級アルキル基を示す。］

[Wherein, R represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, and R ¹¹ represents a lower alkyl group. ]

［式中、Ｒは水素原子、低級アルキル基またはハロゲン化低級アルキル基を示し、Ｒ^１２は低級アルキル基を示す。ｈは１〜３の整数を表す。］

[Wherein, R represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, and R ¹² represents a lower alkyl group. h represents an integer of 1 to 3. ]

In general formula (a1-1-01), R is the same as defined above. The lower alkyl group for R ^{11 is the same as} the lower alkyl group for R, and is preferably a methyl group or an ethyl group.

In general formula (a1-1-02), R is the same as defined above. The lower alkyl group for R ^{12 is the same as} the lower alkyl group for R, preferably a methyl group or an ethyl group, and most preferably an ethyl group. h is preferably 1 or 2, and most preferably 2.

  The proportion of the structural unit (a1) in the component (A1) is preferably 10 to 80 mol%, more preferably 20 to 70 mol%, more preferably 25 to 50 mol%, based on all structural units constituting the component (A1). Is more preferable. By setting it to the lower limit value or more, a pattern can be easily obtained when the positive resist composition is obtained, and by setting the upper limit value or less, it is possible to balance with other structural units.

・ Structural unit (a2)
The structural unit (a2) is a structural unit derived from an acrylate ester containing a lactone-containing cyclic group.
Here, the lactone-containing cyclic group refers to a cyclic group containing one ring (lactone ring) containing an —O—C (O) — structure. The lactone ring is counted as the first ring. When only the lactone ring is present, it is called a monocyclic group, and when it has another ring structure, it is called a polycyclic group regardless of the structure.
When the component (A1) is used for forming a resist film, the lactone cyclic group of the structural unit (a2) increases the adhesion of the resist film to the substrate or has an affinity for a developer containing water. It is effective in raising.

As the structural unit (a2), any unit can be used without any particular limitation.
Specifically, examples of the lactone-containing monocyclic group include groups in which one hydrogen atom has been removed from γ-butyrolactone. Examples of the lactone-containing polycyclic group include groups in which one hydrogen atom has been removed from a bicycloalkane, tricycloalkane, or tetracycloalkane having a lactone ring.

  More specifically, examples of the structural unit (a2) include structural units represented by general formulas (a2-1) to (a2-5) shown below.

［式中、Ｒは水素原子、低級アルキル基またはハロゲン化低級アルキル基であり、Ｒ’は水素原子、低級アルキル基、または炭素数１〜５のアルコキシ基であり、ｍは０または１の整数であり、Ａは炭素数１〜５のアルキレン基または酸素原子である。］

[Wherein, R is a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, R ′ is a hydrogen atom, a lower alkyl group, or an alkoxy group having 1 to 5 carbon atoms, and m is an integer of 0 or 1. And A is an alkylene group having 1 to 5 carbon atoms or an oxygen atom. ]

R in the general formulas (a2-1) to (a2-5) is the same as R in the structural unit (a1).
The lower alkyl group for R ′ is the same as the lower alkyl group for R in the structural unit (a1).
Specific examples of the alkylene group having 1 to 5 carbon atoms of A include a methylene group, an ethylene group, an n-propylene group, and an isopropylene group.
In general formulas (a2-1) to (a2-5), R ′ is preferably a hydrogen atom in view of industrial availability.
Below, the specific structural unit of the said general formula (a2-1)-(a2-5) is illustrated.

  Among these, it is preferable to use at least one selected from general formulas (a2-1) to (a2-5), and at least one selected from general formulas (a2-1) to (a2-3). It is preferable to use more than one species. Specifically, chemical formulas (a2-1-1), (a2-1-2), (a2-2-1), (a2-2-2), (a2-3-1), (a2-3) -2), at least one selected from (a2-3-9) and (a2-3-10) is preferably used.

In the component (A1), as the structural unit (a2), one type of structural unit may be used, or two or more types may be used in combination.
The proportion of the structural unit (a2) in the component (A1) is preferably 5 to 60 mol%, more preferably 10 to 50 mol%, with respect to the total of all the structural units constituting the component (A1). More preferred is mol%. By making it the lower limit value or more, the effect of containing the structural unit (a2) can be sufficiently obtained, and by making it the upper limit value or less, it is possible to balance with other structural units.

・ 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 (A) 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.
Examples of the polar group include a hydroxyl group, a cyano group, a carboxy group, and a hydroxyalkyl group in which a part of hydrogen atoms of an 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 (polycyclic group). It is done. As the polycyclic group, for example, a resin for a resist composition for ArF excimer laser can be appropriately selected from among many proposed ones. The polycyclic group preferably has 7 to 30 carbon atoms.
Among them, a structural unit derived from an acrylate ester containing 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 Is more preferable. Examples of the polycyclic group include groups in which two or more hydrogen atoms have been removed from bicycloalkane, tricycloalkane, tetracycloalkane and 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) 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) ) Is preferable.

［式中、Ｒは前記に同じであり、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。］

[Wherein, R is as defined 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.

  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.

In the component (A1), as the structural unit (a3), one type of structural unit may be used, or two or more types may be used in combination.
The proportion of structural unit (a3) in component (A1) is preferably 5 to 50 mol%, more preferably 5 to 40 mol%, based on all structural units constituting component (A1). 25 mol% is more preferable. By setting it to the lower limit value or more, the effect of containing the structural unit (a3) is sufficiently obtained, and by setting the upper limit value or less, it is possible to balance with other structural units.

・ Structural unit (a4)
The component (A1) may contain other structural units (a4) other than the structural units (a1) to (a3) as long as the effects of the present invention are not impaired.
The structural unit (a4) is not particularly limited as long as it is another structural unit not classified into the above structural units (a1) to (a3), and for ArF excimer laser, for KrF excimer laser (preferably ArF excimer) A number of hitherto known materials can be used for resist resins such as lasers.
As the structural unit (a4), for example, a structural unit derived from an acrylate ester containing a non-acid-dissociable aliphatic polycyclic group is preferable. Examples of the polycyclic group include those exemplified in the case of the structural unit (a1), and for ArF excimer laser and KrF excimer laser (preferably for ArF excimer laser). A number of hitherto known materials can be used as the resin component of the resist composition.
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 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 those represented by the following general formulas (a4-1) to (a4-5).

［式中、Ｒは前記と同じである。］

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

  When the structural unit (a4) is contained in the component (A1), the proportion of the structural unit (a4) is preferably 1 to 30 mol% with respect to the total of all the structural units constituting the component (A1). 10 to 20 mol% is more preferable.

  In the present invention, the component (A1) is a resin component (polymer) whose solubility in an alkali developer is increased by the action of an acid. Examples of suitable resin components (polymers) include structural units. A copolymer having (a1), (a2) and (a3), and examples of such a copolymer include a copolymer composed of structural units (a1), (a2) and (a3), structural units ( Examples thereof include a copolymer comprising a1), (a2), (a3) and (a4).

As the component (A1), one type may be used alone, or two or more types may be used in combination.
In the present invention, as the component (A1), the copolymers (A1-1) to (A1-) containing combinations of structural units represented by the following general formulas (A1-1) to (A1-3) 3) is preferred.

［式中、Ｒは前記と同様であり、複数のＲはそれぞれ同じであっても異なっていても良い。Ｒ^２０は低級アルキル基である。］

[Wherein, R is the same as defined above, and a plurality of R may be the same or different. R ²⁰ is a lower alkyl group. ]

In the formula, R is the same as described above, and among them, a hydrogen atom or a methyl group is preferable.
In the formula, R ²⁰ is a lower alkyl group, preferably a methyl group or an ethyl group.

In the component (A), as the copolymers (A1-1) to (A1-3), one type may be used alone, or two or more types may be used in combination.
And when using combining 2 or more types among copolymers (A1-1)-(A1-3), as a preferable combination of copolymers, a copolymer (A1-2) and a copolymer ( A combination of A1-3) can be exemplified.
The content of the copolymers (A1-1) to (A1-3) in the component (A) is preferably 70% by mass or more, more preferably 80% by mass or more, and 100% by mass. There may be. Especially, it is most preferable that it is 100 mass%. By being at least the lower limit of the range, the lithography properties are further improved when a positive resist composition is obtained.

The component (A1) is obtained by polymerizing a monomer for deriving each structural unit by a known radical polymerization using an azo radical polymerization initiator such as azobisisobutyronitrile (AIBN). Can do.
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 introduced with a hydroxyalkyl group in which a part of hydrogen atoms of the alkyl group is substituted with a fluorine atom reduces development defects and LER (line edge roughness: uneven unevenness of line side walls). It is effective in reducing

The mass average molecular weight (Mw) (polystyrene conversion standard by gel permeation chromatography) of the component (A1) is not particularly limited, but is preferably 2000 to 50000, more preferably 3000 to 30000, and 4000 to 20000. Particularly preferred is 5000 to 20000. Within this range, there is sufficient solubility in a resist solvent for use as a resist, and dry etching resistance and resist pattern cross-sectional shape 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.
As the component (A1), an alkali-soluble resin component other than the copolymers (A1-1) to (A1-3), for example, other polymer compounds used in conventional positive resist compositions, and the like are used. You can also.
In the positive resist composition of the present invention, the content of the component (A1) may be appropriately adjusted according to the resist film thickness to be formed.

<(B) component>
In the resist composition of the present invention, the component (B) contains an acid generator (B1) (hereinafter referred to as the component (B1)) composed of the compound represented by the general formula (b1-14).
In the formula, R ⁷ ″ to R ⁹ ″ and X ⁻ are the same as those described in the compound of the first aspect of the present invention.
When component (B) contains component (B1), mask reproducibility when forming a resist pattern, for example, roundness and diameter of the hole when forming a contact hole (C / H) pattern Lithography properties are improved, such as (CD) uniformity (CDU) is improved, mask error factor (MEF) is improved, and C / H pattern is excellent. Further, when a line-and-space resist pattern (L / S pattern) is formed, the MEF is improved and the lithography characteristics are improved.
The resist composition of the present invention can be suitably used as a resist composition for immersion exposure in a resist pattern forming method including an immersion exposure step, and can provide good lithography characteristics. In a resist pattern forming method including a step of forming a laminate, it can be suitably used as a positive resist composition for forming an upper resist film, and good lithography characteristics can be obtained.
As the component (B1), an anion represented by the general formula “R ¹⁴ SO ₃ ^— ” or “R ¹ —O—Y ¹ —SO ₃ ^— ” as the anion moiety, the general formula (b-3) or It is preferable to use an anion represented by (b-4). The formula further preferably an anion represented by ^"R 14 SO ₃ ^{- -"} or ^"R 1 ^-O-Y 1 -SO _3".

(B) A component can be used 1 type or in mixture of 2 or more types.
In the resist composition of the present invention, the content of the component (B1) in the entire component (B) is preferably 40% by mass or more, more preferably 60% by mass or more, and may be 100% by mass. By being at least the lower limit of the range, the resist pattern shape is good. In particular, when a resist pattern is formed using a resist composition for immersion exposure or a resist composition for forming an upper resist film, the lithography characteristics are improved. When forming a three-layer resist laminate, it is preferable because matching with the lower layer film of the resist is good, and resist pattern tailing and the like can be suppressed.
Moreover, in the resist composition of this invention, it is preferable that content of (B1) component is 1-30 mass parts with respect to 100 mass parts of said (A) component, and is 3-18 mass parts. Is particularly preferable, and is most preferably 5 to 16 parts by mass. By being at least the lower limit of the range, lithography characteristics are improved particularly when a resist pattern is formed using a resist composition for immersion exposure or a resist composition for forming an upper resist film. On the other hand, storage stability will become favorable by being below an upper limit.

In the component (B), an acid generator (B2) other than the component (B1) (hereinafter referred to as the component (B2)) may be used in combination with the component (B1).
The component (B2) is not particularly limited as long as it is other than the component (B1), 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, poly (bissulfonyl) diazomethanes, and the like. 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、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、直鎖状、分岐鎖状または環状のアルキル基またはフッ素化アルキル基を表し；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; among R ¹ ″ to R ³ ″ in formula (b-1), any two but may form a ring with the sulfur atom bonded to each other; R 4 ^"represents a linear, branched or cyclic alkyl group or fluorinated alkyl group; R ¹ At least one of “˜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 ″ are the same as those in the general formula (b1-14) except that an alkoxyalkyloxy group or an alkoxycarbonylalkyloxy group is not substituted with a hydrogen atom. ) Are the same as R ⁷ ″ to R ⁹ ″ in FIG.
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 R ¹ ″ to R ³ ″ are aryl groups.
R ¹ ″ to R ³ ″ are most preferably a phenyl group or a naphthyl group.

R ⁴ ″ represents a linear, branched or cyclic alkyl group or a fluorinated alkyl group.
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 is a cyclic group as indicated by R ¹ ″ and preferably has 4 to 15 carbon atoms, more preferably 4 to 10 carbon atoms, and more preferably 6 carbon atoms. Most preferably, it is -10.
The fluorinated 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 fluorination rate of the fluorinated alkyl group (ratio of fluorine atoms in the alkyl group) is preferably 10 to 100%, more preferably 50 to 100%. Particularly, all the hydrogen atoms are substituted with fluorine atoms. It is preferable because the strength of the acid is increased.
R ⁴ ″ is most preferably a linear or cyclic alkyl group or a fluorinated alkyl 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 the 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 Lopropanesulfonate or its nonafluorobutanesulfonate, trifluoromethanesulfonate of monophenyldimethylsulfonium, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate; trifluoromethanesulfonate of diphenylmonomethylsulfonium, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate (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 heptafluoropropanesulfonate or its nonafluorobutanesulfonate, trifluoromethanesulfonate of diphenyl (1- (4-methoxy) naphthyl) sulfonium, its heptafluoropropane Sulfonate or its nonafluorobutane sulfonate, di (1-naphthyl) phenyl sulphonium trifluoromethane sulphonate, its heptafluoropropane sulphonate or its nonafluorobutane sulphonate; 1-phenyltetrahydrothiophenium trifluoromethane sulphonate, its heptafluoropropane sulphonate 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.
In addition, onium salts in which the anion portion of these onium salts is replaced with methanesulfonate, n-propanesulfonate, n-butanesulfonate, or n-octanesulfonate can also be used.

  In addition, in the general formula (b-1) or (b-2), an onium salt-based acid generator in which the anion moiety is replaced with an anion moiety represented by the following general formula (b-3) or (b-4). 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 and 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, Particularly preferred is an n-butyl group or a tert-butyl group.
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. Examples of the anion moiety include fluorinated alkyl sulfonate ions such as the anion moiety (R ^{4 ″} SO ₃ ⁻ ) of the onium salt acid generator represented by the general formula (b-1) or (b-2). An anion moiety represented by the general formula (b-3) or (b-4), etc. Among them, a fluorinated alkyl sulfonate ion is preferable, and a fluorinated alkyl sulfonic acid having 1 to 4 carbon atoms. Ion is more preferable, and linear perfluoroalkylsulfonic acid ions having 1 to 4 carbon atoms are particularly preferable, and specific examples thereof include trifluoromethylsulfonic acid ions, heptafluoro-n-propylsulfonic acid ions, and nonafluoro-n. -Butyl sulfonate ion etc. are mentioned.

  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 or a fluorinated alkyl group having 1 to 4 carbon atoms which has no substituent.

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), the alkyl group or halogenated alkyl group having no substituent of R ³³ preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and carbon atoms. 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 as those having no substituent of R ³⁵ .
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.

  Of the above exemplified compounds, the following four compounds are preferred.

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.

  As the component (B2), one type of acid generator may be used alone, or two or more types may be used in combination.

  Content of (B) component in the resist composition of this invention is 0.5-30 mass parts with respect to 100 mass parts of (A) component, Preferably it is 1-20 mass parts. 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.

<(D) component>
In the resist composition of the present invention, a nitrogen-containing organic compound (D) (hereinafter referred to as “component (D)”) is further blended as an optional component in order to improve the resist pattern shape, stability over time, etc. be able to.
Since a wide variety of components (D) have already been proposed, any known one may be used. Among them, aliphatic amines, particularly secondary aliphatic amines and tertiary aliphatic amines are used. preferable. Here, “aliphatic” in the claims and the specification is a relative concept with respect to aromatics, and is defined to mean a group, a compound, or the like that does not have aromaticity. “Aliphatic cyclic group” means a monocyclic group or polycyclic group having no aromaticity. An aliphatic amine is an amine having one or more aliphatic groups, and the aliphatic groups preferably have 1 to 12 carbon atoms.
Examples of the aliphatic amine include an amine (alkyl amine 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 12 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, etc .; diethanolamine, triethanolamine, diisopropanolamine Triisopropanolamine, di -n- octanol amines, alkyl alcohol amines tri -n- octanol amine. Among these, a trialkylamine having 5 to 10 carbon atoms is more preferable, tri-n-pentylamine and tri-n-octylamine are particularly preferable, and tri-n-pentylamine is most 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.
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.

<Optional component>
[(E) component]
The resist composition of the present invention comprises, as optional components, an organic carboxylic acid, a phosphorus oxo acid, and derivatives thereof for the purpose of preventing sensitivity deterioration and improving the resist pattern shape, retention stability over time, and the like. At least one compound (E) selected from the group (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.
As the component (E), an organic carboxylic acid is preferable, and salicylic acid is particularly preferable.
(E) A component is used in the ratio of 0.01-5.0 mass parts per 100 mass parts of (A) component.

  If desired, the resist composition of the present invention may further contain miscible additives such as an additional resin for improving the performance of the resist film, a surfactant for improving coatability, a dissolution inhibitor, a plasticizer. An agent, a stabilizer, a colorant, an antihalation agent, a dye, and the like can be appropriately added and contained.

[(S) component]
The 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, and 2-heptanone; many such as ethylene glycol, diethylene glycol, propylene glycol, and dipropylene glycol Monohydric alcohols: compounds having an ester bond such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate or dipropylene glycol monoacetate, monomethyl ether, monoethyl of the polyhydric alcohols or the compound having an ester bond Ether alkyl such as ether, monopropyl ether, monobutyl ether or monophenyl ether Derivatives of polyhydric alcohols such as compounds having a propylene glycol monomethyl ether acetate (PGMEA) or propylene glycol monomethyl ether (PGME) among these]; cyclic ethers such as dioxane, methyl lactate, Esters such as ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate; anisole, ethyl benzyl ether, cresyl methyl ether, diphenyl ether, Aromatic organics such as dibenzyl ether, phenetol, butyl phenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, cymene, mesitylene A solvent etc. can be mentioned.
These organic solvents may be used independently and may be used as 2 or more types of mixed solvents.
Among these, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), ethyl lactate (EL), and γ-butyrolactone are preferable.
Moreover, the mixed solvent which mixed PGMEA and the polar solvent is 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.
Furthermore, as the component (S), a mixed solvent of the above-described mixed solvent of PGMEA and PGME and γ-butyrolactone is also preferable. In this case, as a mixing ratio, the mass ratio of the former and the latter is preferably 99.9: 0.1 to 80:20, more preferably 99.9: 0.1 to 90:10, Most preferably, it is 99.9: 0.1-95: 5. By setting it as the said range, the rectangularity of a resist pattern improves.
The amount of the 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 2 -20% by mass, preferably 5-15% by mass.

In this invention, the acid generator (B1) which consists of a compound represented by the said general formula (b1-14) is used. The component (B1) has a structure in which a hydroxyl group bonded to an aryl group is protected with an acetal type acid-dissociable group such as a tertiary alkyl ester type or an alkoxyalkyl group. The structure does not change. Therefore, it is considered that the compound represented by the general formula (b1-14) exhibits a dissolution inhibiting effect on the alkali developer with respect to the component (A1) in the non-exposed portion of the resist film.
On the other hand, in the exposed area, during the post-exposure heating (PEB) with the generated acid, the acid dissociable group is dissociated from the oxygen atom constituting the hydroxyl group, resulting in a compound in which the hydroxyl group is bonded to the aryl group, It is considered that the component (A1) exhibits an effect of promoting dissolution in an alkali developer.
Therefore, it is considered that the contrast of the exposed / non-exposed area can be increased.

For the above reasons, when the resist composition of the present invention is a positive resist composition, a resist pattern is formed by using a combination of a base material component and an acid generator (the (B1) component). Mask reproducibility, for example, when a contact hole (C / H) pattern is formed, the roundness of the hole, uniformity of the diameter (CD) (CDU) is improved, and mask error factor (MEF) is improved. Therefore, it is presumed that the lithography characteristics are improved, such as excellent C / H pattern removal. Further, it is presumed that the lithography characteristics are improved, for example, MEF is improved when a line and space resist pattern (L / S pattern) is formed.
The resist composition of the present invention can be suitably used as a resist composition for immersion exposure in a resist pattern forming method including an immersion exposure step, and can provide good lithography characteristics. In a resist pattern forming method including a step of forming a laminate, it can be suitably used as a positive resist composition for forming an upper resist film, and it is considered that good lithography characteristics can be obtained.

≪Resist pattern formation method≫
Next, a resist pattern forming method according to the fourth aspect of the present invention will be described.
The resist pattern forming method of the present invention includes a step of forming a resist film on a support using the resist composition of the third aspect of the present invention, a step of exposing the resist film, and an alkali development of the resist film. Then, the method includes a step of forming a resist pattern.

The resist pattern forming method of the present invention can be performed, for example, as follows.
That is, first, the resist composition according to the third aspect of the present invention is applied onto a support with a spinner or the like, and prebaked (post-apply bake (PAB)) for 40 to 120 seconds under a temperature condition of 80 to 150 ° C. , Preferably for 60 to 90 seconds, and selectively exposed to ArF excimer laser light through a desired mask pattern using, for example, an ArF exposure apparatus, followed by heating after exposure under a temperature condition of 80 to 150 ° C. Post exposure bake (PEB) treatment) is performed for 40 to 120 seconds, preferably 60 to 90 seconds. Subsequently, this is developed with an alkali developer, for example, an aqueous solution of 0.1 to 10% by mass of tetramethylammonium hydroxide, 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 substrate 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, particularly ArF excimer laser. It is also effective for immersion exposure.

  Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.

(Synthesis Example 1)
<Synthesis of Compound (1)>

Phosphorus oxide (8.53 g), 2,6-dimethylphenol (8.81 g) and diphenyl sulfoxide (12.2 g) were added in small portions to methanesulfonic acid (60.75 g) controlled at 20 ° C. or lower. After aging for 30 minutes while controlling the temperature at 15 to 20 ° C., the temperature was raised to 40 ° C. and aging was performed for 2 hours. Then, the reaction liquid was dripped at the pure water (109.35g) cooled to 15 degrees C or less. After completion of the dropwise addition, dichloromethane (54.68 g) was added, and after stirring, the dichloromethane layer was recovered. In a separate container, hexane (386.86 g) at 20 to 25 ° C. was charged, and the dichloromethane layer was added dropwise. After completion of the dropping, the mixture was aged at 20 to 25 ° C. for 30 minutes, and then filtered to obtain the target compound (yield 70.9%).
The obtained compound was analyzed by ¹ H-NMR.
¹ H-NMR (DMSO-d6, 600 MHz): δ (ppm) = 7.61-7.72 (m, 10H, phenyl), 7.14 (S, 2H, H ^c ), 3.12 (S, 3H, H ^b ), 2.22 (s, 6H, H ^a ).
From the above results, it was confirmed that the obtained compound had the structure shown below.

(Synthesis Example 2)
<Synthesis of Compound (2)>

5.00 g of compound (1) was dissolved in a mixed solution of 25.00 g of water and 24.03 g of dichloromethane. Thereafter, lithium 2-naphthylmethoxytetrafluoroethanesulfonate (4.28 g) was added in small portions and stirred at 25 ° C. for 1 hour. After completion of the reaction, the dichloromethane solution was washed with water and then concentrated to dryness. The obtained powder was dispersed and washed with hexane and then dried under reduced pressure to obtain 7.23 g of the target compound (yield 90.2%).
The obtained compound was analyzed by ¹ H-NMR and ¹⁹ F-NMR.
¹ H-NMR (DMSO-d6, 600 MHz): δ (ppm) = 7.97 (s, 1H, H ^c ), 7.94-7.91 (m, 3H, phenyl + naphthyl), 7.83-7. 81 (m, 2H, phenyl + naphthyl), 7.76-7.75 (m, 8H, phenyl + naphthyl), 7.55-7.52 (m, 3H, phenyl + naphthyl), 7.496 (s, 2H, H ^d ) , 5.21 (s, 2H, H ^b ), 2.24 (s, 6H, H ^a ).
¹⁹ F-NMR (Acetone-d6, 376 MHz): δ (ppm) = − 82.8, −115.8.
From the above results, it was confirmed that the compound had the structure shown below.

Example 1
<Synthesis of Compound (b1-14-101)>

Compound (1) (12.1 g) was dissolved in dichloromethane (54.6 g) and water (60.4 g), potassium nonafluoro-n-butanesulfonate (11.2 g) was added thereto, and the mixture was stirred at room temperature for 1 hour. did. Thereafter, liquid separation was performed, and the organic layer was washed with water and concentrated to dryness to obtain 16.5 g of a compound in which the anion of the compound (1) was replaced with nonafluoro-n-butanesulfonic acid anion. This compound (6.1 g) was dissolved in 80.9 g of dehydrated tetrahydrofuran and ice-cooled to 10 ° C. or lower. Sodium hydride (0.44 g) was added thereto, and then a solution of 2-adamantane chloromethyl ether (2.2 g) in tetrahydrofuran (4.4 g) was added dropwise. After completion of the dropwise addition, the mixture was warmed to room temperature and stirred for 1 hour, and then the reaction solution was dropped into water, and the solution was extracted with dichloromethane (90 g). Thereafter, the dichloromethane layer was washed with dilute hydrochloric acid and washed with water. The dichloromethane solution was dropped into hexane (150 g) to obtain 6.9 g of the target product as a white powder.
The obtained compound was analyzed by ¹ H-NMR and ¹⁹ F-NMR.
¹ H-NMR (DMSO-d6, 400 MHz): δ (ppm) = 7.76-7.88 (m, 10H, H ^a -H ^e ), 7.60 (s, 2H, H ^f ), 5. ^{24 (s, 2H, H g} ), 3.88 (s, 1H, H h), 2.33 (s, 6H, H i), 1.46-1.99 (m, 14H, Adamantane).
¹⁹ F-NMR (DMSO-d6, 376 MHz): δ (ppm) = − 80.4, −114.6, −121.1, −125.3.
From the above results, it was confirmed that the compound had the structure shown below.

(Example 2)
<Synthesis of Compound (b1-14-201)>

To 75 ml of tetrahydrofuran solution, 5.00 g of compound (2) was added and ice-cooled. 0.34 g of sodium hydride was added thereto, and then a solution of 2-adamantane chloromethyl ether (1.713 g) in tetrahydrofuran (3.42 ml) was added dropwise. After completion of the dropping, the mixture was warmed to room temperature and stirred for 1 hour, and then the reaction solution was dropped into water, and the solution was extracted with dichloromethane (60.4 g). Thereafter, the dichloromethane layer was washed with dilute hydrochloric acid and washed with water. The dichloromethane solution was concentrated to dryness, and the obtained powder was dispersed with hexane. Then, the objective compound 4.27g was obtained by drying under reduced pressure (yield 68.1%).
The obtained compound was analyzed by ¹ H-NMR and ¹⁹ F-NMR.
^{1 H-NMR (DMSO-d6,600MHz} ): δ (ppm) = 7.89 (s, 1H, H e), 7.87-7.59 (m, 13H, phenyl + naphthyl), 7.561 (s, ^{2H, H e), 7.54-7.52 (} m, 3H, phenyl + naphthyl), 5.23-5.21 (d, 4H, H d), 3.87 (s, 1H, H f), 2 .33 (s, 6H, H ^a ), 1.99-1.45 (m, 14H, Adamantane).
¹⁹ F-NMR (Acetone-d6, 376 MHz): δ (ppm) = − 82.9, −115.9.
From the above results, it was confirmed that the compound had the structure shown below.

(Example 3)
<Synthesis of Compound (b1-14-301)>

In Example 2, the reaction was performed in the same manner except that 2-adamantane chloromethyl ether was changed to an equimolar amount of 2-methyl-2-adamantane bromoacetate.
The obtained compound was analyzed by ¹ H-NMR and ¹⁹ F-NMR.
¹ H-NMR (CDCl ₃ , 400 MHz): δ (ppm) = 7.84 (s, 1H, H ^f ), 7.71-7.77 (m, 3H, Phenyl + Naphthyl), 7.57-7.67 (m, 10H, Phenyl + Naphthyl ), 7.39-7.51 (m, 3H, Phenyl + Naphthyl), 7.36 (s, 2H, H d), 5.19 (s, 2H, H c), 4.38 (S, 2H, H ^b ), 2.32 (s, 6H, H ^a ), 1.69-1.97 (m, 11H, Adamantan), 1.66 (s, 3H, H ^e ), 1. 55-1.58 (d, 3H, Adamantan).
¹⁹ F-NMR (CDCl ₃ , 400 MHz): δ (ppm) = − 76.87, −109.14.
From the above results, it was confirmed that the compound had the structure shown below.

(Examples 4-6, Comparative Example 1)
<Preparation of positive resist composition>
Each component shown in Table 1 was mixed and dissolved to prepare a positive resist composition.

Each abbreviation in Table 1 has the following meaning. Moreover, the numerical value in [] of Table 1 is a compounding quantity (mass part).
(A) -1: a polymer represented by the following chemical formula (A) -1.
(B) -1: An acid generator (compound of Example 1) represented by the chemical formula (b1-14-101).
(B) -2: An acid generator (compound of Example 2) represented by the chemical formula (b1-14-201).
(B) -3: An acid generator (compound of Example 3) represented by the chemical formula (b1-14-301).
(B) -4: Triphenylsulfonium nonafluoro-n-butanesulfonate.
(D) -1: tri-n-pentylamine.
(S) -1: PGMEA / PGME = 6/4 (mass ratio) mixed solvent.
The blending amounts of (B) -1 to (B) -4 are equimolar amounts.

［Ｍｗ＝７０００、Ｍｗ／Ｍｎ＝２．０。］

[Mw = 7000, Mw / Mn = 2.0. ]

<Evaluation of lithography properties>
A resist pattern was formed using the obtained positive resist composition solution, and the following lithography characteristics were evaluated.

[Resolution and sensitivity]
An organic antireflection film composition “ARC29” (trade name, manufactured by Brewer Science Co., Ltd.) is applied onto an 8-inch silicon wafer using a spinner, and baked at 205 ° C. for 60 seconds on a hot plate and dried. Thereby, an organic antireflection film having a film thickness of 89 nm was formed. Then, the positive resist composition solution obtained above is applied onto the antireflection film using a spinner, and prebaked (PAB) is performed on a hot plate at 100 ° C. for 60 seconds. By drying, a resist film having a thickness of 120 nm was formed.

Next, a protective film-forming coating solution “TSRC-002” (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.) is applied onto the resist film using a spinner and heated at 90 ° C. for 60 seconds. A top coat having a thickness of 28 nm was formed.
Next, holes with a hole diameter (CD) of 75 nm are equally spaced (pitch 131 nm) by ArF immersion exposure apparatus NSR-S609B (Nikon Corporation; NA (numerical aperture) = 1.07, 2/3 annular illumination). ArF excimer laser (193 nm) was selectively irradiated to the resist film on which the top coat was formed through the hole pattern mask (bias 0 nm).
The top coat is removed using a protective film removing solution “TS-Remover-S” (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.), and then a post-exposure heating (PEB) treatment is performed at 95 ° C. for 60 seconds. Furthermore, it develops for 30 seconds with 2.38 mass% tetramethylammonium hydroxide (TMAH) aqueous solution "NMD-W" (made by Tokyo Ohka Kogyo Co., Ltd.) at 23 degreeC, Then, the water rinse is carried out using pure water for 30 seconds. Then, it was shaken and dried.
As a result, a contact hole pattern (C / H pattern) in which holes with a hole diameter (CD) of 70 nm were arranged at equal intervals (pitch 131 nm) was formed on the resist film.
Moreover, the optimal exposure amount (sensitivity: Eop, mJ / cm < ² >) in that case was calculated | required. As a result, Example 4 is 61mJ / cm ^2, Example 5 was 85 mJ / cm ^2, Example 6 was 57mJ / cm ^2, Comparative Example 1 was 34 mJ / cm ^2.

[Pattern shape]
When the C / H pattern having a hole diameter of 70 nm and a pitch of 131 nm was observed with a scanning electron microscope (trade name: S-9220, manufactured by Hitachi, Ltd.), the C / H patterns of Examples 4 to 6 were easily removed. Was clearly superior to Comparative Example 1. In the C / H pattern of Comparative Example 1, a part of the pattern was not completely removed.

[MEF evaluation]
With the EOP, a C / H pattern was formed using a mask pattern targeting a diameter of 70 nm and a pitch of 131 nm and a mask pattern targeting a diameter of 75 nm and a pitch of 131 nm, and the MEF value was obtained from the following equation: .
MEF = | CD ₇₅ -CD ₇₀ | / | MD ₇₅ -MD ₇₀ |
In the above formula, CD ₇₅ and CD ₇₀ are actual apertures (nm) of C / H patterns formed using mask patterns targeting apertures of 75 nm and 70 nm, respectively. Further, MD ₇₅ and MD ₇₀ are the apertures (nm) targeted by the mask pattern, respectively, and MD ₇₅ = 75 and MD ₇₀ = 70.
When the mask size (the hole diameter in the C / H pattern or the line width in the line and space pattern) is changed with the same exposure amount and the pitch fixed, the MEF is faithful to how much the mask pattern is different in size. It is a parameter indicating whether or not the value can be reproduced, and the closer the MEF value is to 1, the better the mask reproducibility. As a result of the evaluation, it was confirmed that Examples 4 to 6 had better mask reproducibility than Comparative Example 1.

[CD uniformity (CDU) evaluation]
With respect to the C / H pattern obtained by the EOP, the CD of 25 holes in each C / H pattern was measured, and a triple value (3σ) of the standard deviation (σ) calculated from the result was obtained. 3σ obtained in this way means that the smaller the value, the higher the CD uniformity (CDU) of each hole formed in the resist film.
As a result of the evaluation, Example 4 was 13.65, Example 5 was 14.51, Example 6 was 11.99, and Comparative Example 1 was 16.60.

[Roundness evaluation]
The C / H pattern obtained by the EOP was observed from above, and 25 holes in each C / H pattern were measured with a length measurement SEM (manufactured by Hitachi, Ltd., product name: S-9220). The distance from the center to the outer edge was measured in 24 directions, and a triple value (3σ) of the standard deviation (σ) calculated from the result was obtained. The 3σ obtained in this way means that the smaller the value, the higher the roundness of the hole.
As a result of the evaluation, Example 4 was 5.5, Example 5 was 4.7, Example 6 was 4.1, and Comparative Example 1 was 5.2. Example 4 has the same roundness as that of Comparative Example 1, and Examples 5 to 6 were more excellent in roundness than Comparative Example 1.

  From the above results, the resist composition containing the acid generator of the present invention has a good pattern shape, excellent MEF, CDU, and roundness, and better lithography than a resist composition containing a conventional acid generator. It was confirmed that the characteristics were obtained.

(Example 7)
<Synthesis of Compounds (b1-14-501) to (b1-14-503)>

Compound (1) (4 g) was dissolved in dichloromethane (79.8 g). After confirmation of dissolution, potassium carbonate (6.87 g) was added, and 2-methyl-2-adamantane bromoacetate (3.42 g) was added. After reaction for 24 hours under reflux, filtration, washing with water were performed, and crystallization was performed with hexane. The obtained powder was dried under reduced pressure to obtain 3.98 g of the target compound (yield 66%).
The compound was analyzed by ¹ H-NMR. The results are shown below.
¹ H-NMR (CDCl ₃ , 600 MHz): δ (ppm) = 7.83-7.86 (m, 4H, phenyl), 7.69-7.78 (m, 6H, phenyl), 7.51 ( s, 2H, Hd), 4.46 (s, 2H, Hc), 2.39 (s, 6H, Ha), 2.33 (s, 2H, Adamantane), 2.17 (s, 2H, Adamantane) , 1.71-1.976 (m, 11H, Adamantane), 1.68 (s, 3H, Hb), 1.57-1.61 (m, 2H, Adamantane).
From the results described above, it was confirmed that the obtained compound contained a compound (b1-14-501) having the structure shown below. Furthermore, it was confirmed from the measurement results of ion chromatography that the obtained compound contains compounds (b1-14-502) and (b1-14-503) having the same NMR data of the cation moiety as described above. It was done. The ratio of these compounds was 21.4 mol% of the compound (b1-14-501), 11.4 mol% of the compound (b1-14-502), and 67.2 mol% of (b1-14-503).

(Example 8)
<Synthesis of Compound (b1-14-401)>

25.5 g of a mixture of 21.4 mol% of the compound (b1-14-501), 11.4 mol% of the compound (b1-14-502) and 67.2 mol% of (b1-14-503) was dissolved in 200 g of pure water. Thereto were added dichloromethane (127.4 g) and potassium nonafluoro-n-butanesulfonate (16.0 g), and the mixture was stirred at room temperature for 14 hours. Thereafter, the dichloromethane layer was separated, washed with dilute hydrochloric acid, washed with ammonia, and washed with water, and the dichloromethane layer was concentrated and dried to obtain the desired product (32.9 g) as a white solid.
The obtained compound was analyzed by ¹ H-NMR and ¹⁹ F-NMR.
¹ H-NMR (DMSO-d6, 400 MHz): δ (ppm) = 7.75-7.86 (m, 10H, ArH), 7.61 (s, 2H, ArH), 4.62 (s, 2H) _{, CH 2), 2.31 (s} , 6H, CH 3), 1.49-1.97 (m, 17H, Adamantane).
¹⁹ F-NMR (DMSO-d6, 376 MHz): δ (ppm) = − 77.8, −112.2, −118.7, −123.0.
From the above results, it was confirmed that the compound had the above structure.

Example 9
<Synthesis of Compound (b1-14-402)>

80.4 g of a mixture of 21.4 mol% of the compound (b1-14-501), 11.4 mol% of the compound (b1-14-502) and 67.2 mol% of (b1-14-503) was added to 70.4 g of pure water. Then, dichloromethane (44.7 g) and potassium trifluoromethanesulfonate (3.12 g) were added thereto, and the mixture was stirred at room temperature for 14 hours. Thereafter, the dichloromethane layer was separated, washed with dilute hydrochloric acid, washed with ammonia, and washed with water. The dichloromethane layer was concentrated and dried to obtain the desired product (8.70 g) as a white solid.
The obtained compound was analyzed by ¹ H-NMR and ¹⁹ F-NMR.
¹ H-NMR (DMSO-d6, 400 MHz): δ (ppm) = 7.74-7.86 (m, 10H, ArH), 7.60 (s, 2H, ArH), 4.62 (s, 2H) _{, CH 2), 2.31 (s} , 6H, CH 3), 1.49-1.97 (m, 17H, Adamantane).
¹⁹ F-NMR (DMSO-d6, 376 MHz): δ (ppm) = − 75.2.
From the above results, it was confirmed that the compound had the above structure.

(Examples 10 to 17, Comparative Example 2)
<Preparation of positive resist composition>
Each component shown in Table 2 was mixed and dissolved to prepare a positive resist composition.

Each abbreviation in Table 2 has the following meaning. Moreover, the numerical value in [] of Table 2 is a compounding quantity (mass part).
(A) -2: a polymer represented by the following chemical formula (A) -2 (Mw = 7000, Mw / Mn = 1.8).
(A) -3: A polymer represented by the following chemical formula (A) -2 (Mw = 10000, Mw / Mn = 2.0).
(A) -4: A polymer represented by the following chemical formula (A) -4 (Mw = 5000, Mw / Mn = 1.5).
(B) -5: An acid generator (compound of Example 8) represented by the chemical formula (b1-14-401).
(B) -6: Triphenylsulfonium trifluoromethanesulfonate.
(B) -7: Di (1-naphthyl) phenylsulfonium nonafluoro-n-butanesulfonate.
(B) -8: 4-Methylphenyldiphenylsulfonium nonafluoro-n-butanesulfonate.

<Evaluation of lithography properties>
A resist pattern was formed using the obtained positive resist composition solution, and the following lithography characteristics were evaluated.

[Resolution and sensitivity]
An organic antireflection film composition “ARC29” (trade name, manufactured by Brewer Science Co., Ltd.) is applied onto an 8-inch silicon wafer using a spinner, and baked on a hot plate at 205 ° C. for 60 seconds to be dried. Thereby, an organic antireflection film having a film thickness of 75 nm was formed. Then, the positive resist composition solution obtained above is applied onto the antireflection film using a spinner, and prebaked (PAB) is performed on a hot plate at 110 ° C. for 60 seconds, By drying, a resist film having a thickness of 120 nm was formed.

Next, ArF immersion exposure apparatus NSR-S609B (manufactured by Nikon Corporation; NA (numerical aperture) = 1.07, illumination condition = X-pole. (0.78 / 0.97), polarization condition = w / P) , ArF excimer laser (193 nm) was selectively irradiated through a mask pattern (6% halftone). Then, a post-exposure heating (PEB) treatment was performed at 110 ° C. for 60 seconds, and a 2.38 mass% tetramethylammonium hydroxide (TMAH) aqueous solution “NMD-3” (Tokyo Ohka Kogyo Co., Ltd.) at 23 ° C. The product was developed for 40 seconds, rinsed with pure water for 40 seconds, and then shaken and dried.
As a result, a line and space resist pattern (L / S pattern) having a line width of 65 nm and a pitch of 130 nm was formed in any of the examples using the positive resist composition.
Moreover, the optimal exposure amount (sensitivity: Eop, mJ / cm < ² >) in that case was calculated | required. The results are shown in Table 3.

[MEF evaluation]
In the above Eop, L / S patterns with a pitch of 130 nm were formed using mask patterns with line width target sizes of 61 nm, 63 nm, 65 nm, 67 nm, and 69 nm, respectively. At this time, the slope of the straight line when the target size (nm) was plotted on the horizontal axis and the line width (nm) formed on the resist film using each mask pattern was plotted on the vertical axis was calculated as MEF. MEF (straight line) means that the closer the value is to 1, the better the mask reproducibility. The obtained results are shown in Table 3.

  As is clear from the above results, it was confirmed that the resist compositions of Examples 10 to 17 containing the acid generator of the present invention had better mask reproducibility than the resist composition of Comparative Example 2.

Claims (11)

The compound represented by the following general formula (b1-14).

[Wherein, R ⁷ ″ to R ⁹ ″ each independently represents an aryl group or an alkyl group; any two of R ⁷ ″ to R ⁹ ″ are bonded to each other to form a sulfur atom in the formula May form a ring; at least one of R ⁷ ″ to R ⁹ ″ is a substituted aryl group in which part or all of the hydrogen atoms are substituted with an alkoxyalkyloxy group or an alkoxycarbonylalkyloxy group; X ⁻ is an anion. ] The alkoxyalkyloxy group is represented by the following general formula (b14-1)

[Wherein, R ⁴⁷ and R ⁴⁸ are each independently a hydrogen atom or a linear or branched alkyl group, R ⁴⁹ is an alkyl group, and R ⁴⁸ and R ⁴⁹ are bonded to each other. Two ring structures may be formed. However, at least one of R ⁴⁷ and R ⁴⁸ is a hydrogen atom. ]
It is represented by
The alkoxycarbonylalkyloxy group is represented by the following general formula (b14-2)

[Wherein, R ⁵⁰ is a linear or branched alkylene group, and R ⁵¹ is an acid dissociable group. ]
The compound of Claim 1 which is represented by these.   An acid generator comprising the compound according to claim 1 or 2. A resist composition containing a base component (A) whose solubility in an alkaline developer is changed by the action of an acid and an acid generator component (B) that generates an acid upon exposure,
The said acid generator component (B) contains the acid generator (B1) which consists of a compound represented by the following general formula (b1-14), The resist composition characterized by the above-mentioned.

[Wherein, R ⁷ ″ to R ⁹ ″ each independently represents an aryl group or an alkyl group; any two of R ⁷ ″ to R ⁹ ″ are bonded to each other to form a sulfur atom in the formula May form a ring; at least one of R ⁷ ″ to R ⁹ ″ is a substituted aryl group in which part or all of the hydrogen atoms are substituted with an alkoxyalkyloxy group or an alkoxycarbonylalkyloxy group; X ⁻ is an anion. ] The alkoxyalkyloxy group is represented by the following general formula (b14-1)

[Wherein, R ⁴⁷ and R ⁴⁸ are each independently a hydrogen atom or a linear or branched alkyl group, R ⁴⁹ is an alkyl group, and R ⁴⁸ and R ⁴⁹ are bonded to each other. Two ring structures may be formed. However, at least one of R ⁴⁷ and R ⁴⁸ is a hydrogen atom. ]
It is represented by
The alkoxycarbonylalkyloxy group is represented by the following general formula (b14-2)

[Wherein, R ⁵⁰ is a linear or branched alkylene group, and R ⁵¹ is an acid dissociable group. ]
The resist composition according to claim 4, which is represented by:   The resist composition according to claim 4 or 5, wherein the substrate component (A) is a substrate component whose solubility in an alkaline developer is increased by the action of an acid.   The resist composition according to claim 6, wherein the substrate component (A) is a resin component (A1) and has a structural unit (a1) derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group.   The resist composition according to claim 7, wherein the base component (A) further has a structural unit (a2) derived from an acrylate ester containing a lactone-containing cyclic group.   The resist composition according to claim 7 or 8, wherein the substrate component (A) further comprises a structural unit (a3) derived from an acrylate ester containing a polar group-containing aliphatic hydrocarbon group.   The resist composition as described in any one of Claims 4-9 containing a nitrogen-containing organic compound (D).   A step of forming a resist film on a support using the resist composition according to any one of claims 4 to 10, a step of exposing the resist film, and an alkali development of the resist film to form a resist pattern A resist pattern forming method including a forming step.