JP5210610B2 - Resist composition for immersion exposure and method for forming resist pattern - Google Patents

Description

  The present invention relates to a resist composition for liquid immersion lithography and a resist pattern forming method using the resist composition for liquid immersion exposure.

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 light 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.
Along with the miniaturization of semiconductor elements, the wavelength of the exposure light source has been shortened and the projection lens has a high numerical aperture (high NA). A machine has been developed. Along with the shortening of the wavelength of the exposure light source, the resist material is required to be improved in lithography characteristics such as sensitivity to the exposure light source and resolution capable of reproducing a pattern with a fine dimension. 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.
At present, as a base resin of a chemically amplified resist used in ArF excimer laser lithography and the like, a resin having a structural unit derived from (meth) acrylic acid ester in the main chain because of its excellent transparency near 193 nm ( Acrylic resin) is generally used.
Here, “(meth) acrylic acid” means one or both of acrylic acid having a hydrogen atom bonded to the α-position and methacrylic acid having a methyl group bonded to the α-position. “(Meth) acrylic acid ester” means one or both of an acrylic acid ester having a hydrogen atom bonded to the α-position and a methacrylic acid ester having a methyl group bonded to the α-position. “(Meth) acrylate” means one or both of an acrylate having a hydrogen atom bonded to the α-position and a methacrylate having a methyl group bonded to the α-position.

As one of the methods for further improving the resolution, exposure (immersion exposure) is performed by interposing a liquid (immersion medium) having a higher refractive index than air between the objective lens of the exposure machine and the sample. A so-called immersion lithography (hereinafter referred to as “immersion exposure”) is known (for example, see Non-Patent Document 1).
According to immersion exposure, even when a light source having the same exposure wavelength is used, the same high resolution as when using a light source with a shorter wavelength or using a high NA lens can be achieved, and the depth of focus can be reduced. It is said that there is no decline. Moreover, immersion exposure can be performed using an existing exposure apparatus. For this reason, immersion exposure is expected to be able to form resist patterns with low cost, high resolution, and excellent depth of focus. In particular, in terms of lithography characteristics such as resolution, the semiconductor industry is attracting a great deal of attention.
Immersion exposure is effective in forming all pattern shapes, and can be combined with super-resolution techniques such as the phase shift method and the modified illumination method that are currently under investigation. Currently, as an immersion exposure technique, a technique mainly using an ArF excimer laser as a light source is being actively researched. Currently, water is mainly studied as an immersion medium.
Proceedings of SPIE, 5754, 119-128 (2005).

  In immersion exposure, in addition to normal lithography characteristics (sensitivity, resolution, etching resistance, etc.), a resist material having characteristics corresponding to the immersion exposure technique is required. For example, in immersion exposure, when the resist film and the immersion solvent come into contact with each other, elution of the substance in the resist film into the immersion solvent (substance elution) occurs. Substance elution causes phenomena such as alteration of the resist layer and change in the refractive index of the immersion solvent, thereby deteriorating the lithography properties.

  The present invention has been made in view of the above circumstances, and is a resist composition for immersion exposure with a small amount of substance elution with respect to an immersion solvent, particularly water, and resist pattern formation using the resist composition for immersion exposure It aims to provide a method.

また、本発明の第二の態様は、前記第一の態様の液浸露光用レジスト組成物を用いて支持体上にレジスト膜を形成する工程、前記レジスト膜を露光する工程、および前記レジスト膜をアルカリ現像してレジストパターンを形成する工程を含むレジストパターン形成方法である。 The first aspect of the present invention that solves the above-described problems includes a base material 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 1-octanol / water partition coefficient of the cation component of the acid generator component (B) is 7.0 to 11.0 , and the cation component of the acid generator component (B) When an alkoxycarbonylalkyloxy group is included, the number of the alkoxycarbonyloxy groups is one (however, the cation component of the acid generator component (B) is excluded from the cation represented by the following chemical formula). The resist composition for immersion exposure.

The second aspect of the present invention includes a step of forming a resist film on a support using the resist composition for immersion exposure according to the first aspect, 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, unless otherwise specified, the “alkyl group” includes linear, branched and cyclic monovalent saturated hydrocarbon groups.
The “lower alkyl group” is an alkyl group having 1 to 5 carbon atoms.
Unless otherwise specified, the “alkylene group” includes linear, branched and cyclic divalent saturated hydrocarbon groups.
The “structural unit” means a monomer unit (monomer unit) constituting a polymer compound (polymer, copolymer).
“Exposure” is a concept that includes general irradiation of radiation.

  INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a resist composition for immersion exposure with a small amount of substance elution with respect to an immersion solvent, particularly water, and a resist pattern forming method using the resist composition for immersion exposure.

≪Resist composition for immersion exposure≫
The resist composition for immersion exposure according to the first aspect of the present invention comprises a substrate 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 upon exposure. Is a resist composition containing an acid generator component (B) (hereinafter referred to as the component (B)) that generates an acid, wherein the 1-octanol / water partition coefficient of the cation component of the component (B) is 7.0 to 7.0. It is 9.5.
First, the component (B) will be described.

<(B) component>
In the present invention, the 1-octanol / water partition coefficient (Log P) of the cation component of the component (B) Computational Chem. , 9 (1), 80-90 (1988), the index value obtained by the relational expression of the structure-activity relationship. Specifically, for the target acid generator component (B), first, PM3 "is used to optimize the molecular structure of the cation component of the compound in terms of energy. The optimized structure is then used to Computational Chem. 9 (1), 80-90 (1988), the 1-octanol / water partition coefficient (LogP) can be determined. The 1-octanol / water partition coefficient (LogP) indicates that the smaller the value, the more water is distributed, and the larger the value, the more octanol is distributed.

  When the 1-octanol / water partition coefficient (LogP) of the cation component of component (B) is 7.0 to 11.0, a resist composition for immersion exposure with a smaller amount of substance elution is obtained during immersion exposure. Can be obtained. The 1-octanol / water partition coefficient (Log P) of the cation component of the acid generator component (B) is more preferably 7.0 to 10.5, and particularly preferably 7.0 to 9.0. Preferably it is 7-8.0.

  (B) As a compound which comprises a component, it is easy to adjust 1-octanol / water partition coefficient (LogP) of a cation component to the range of 7.0-11.0, and is the following general formula (b1-14) The compounds represented are preferred.

［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 together with a sulfur atom in the formula A ring may be formed; 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. ]

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 be substituted for the hydrogen atom of the aryl group is preferably a fluorine atom.
The alkyl group for R ⁷ ″ to R ⁹ ″ is not particularly limited, and examples thereof include a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms. 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, 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- to 7-membered ring, and more preferably a 4- to 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 represents a linear or branched alkylene group, and R ⁵¹ represents 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; an acetal type such as an alkoxyalkyl 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 ″ —O—Y ¹ —SO ₃ ^— (R ″ is a monovalent aliphatic hydrocarbon group, monovalent aromatic organic group, or hydroxyalkyl group; Y ¹ is fluorine-substituted; An anion represented by the above-mentioned alkylene group having 1 to 4 carbon atoms.

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 one 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 them, 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 preferable fluorinated alkyl group include a trifluoromethyl group, a heptafluoro-n-propyl group, and a nonafluoro-n-butyl group, and a nonafluoro-n-butyl group is particularly preferable.
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 ″ —O—Y ¹ —SO ₃ ^— ”, R ″ is a monovalent aliphatic hydrocarbon group, aromatic organic group, or hydroxyalkyl group; Y ¹ is fluorine-substituted. And an alkylene group having 1 to 4 carbon atoms.

  Examples of the monovalent aliphatic hydrocarbon group represented by R ″ include, for example, a linear, branched or cyclic monovalent saturated hydrocarbon group having 1 to 15 carbon atoms, or a straight chain having 2 to 5 carbon atoms. A linear or branched monovalent aliphatic unsaturated hydrocarbon group may be mentioned.

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. Group 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.
2-4 are preferable and, as for carbon number of the monovalent aliphatic hydrocarbon group of R '', 3 is especially preferable.

  Examples of the monovalent aromatic organic group for R ″ include aromatic hydrocarbon rings such as a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, an anthryl group, and a phenanthryl group. Aryl groups from which one hydrogen atom has been removed; heteroaryl groups in which some of the carbon atoms constituting the ring of these aryl groups are substituted with heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms; benzyl groups, phenethyl groups Arylalkyl groups such as 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2-naphthylethyl group, and the like. The number of carbon atoms in the alkyl chain in the arylalkyl group is preferably 1 to 4, 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 for R ″ 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.
1-10 are preferable, as for carbon number of the monovalent | monohydric hydroxyalkyl group of R '', 1-8 are more preferable, 1-6 are especially preferable, and 1-3 are the most preferable.

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 ⁻ can 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 an alkyl group having 1 to 10 carbon atoms and 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 ″ are each independently 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 X ″ alkylene group or the number of carbon atoms of the Y ″ and Z ″ alkyl groups is preferably as small as possible because the solubility in a resist solvent is good within the above-mentioned range of carbon numbers.
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 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.

  Preferred specific examples of the compound are listed below.

  Among these, the compounds represented by the chemical formulas (b1-14-101) and (b1-14-301) are preferable.

<Method for producing compound>
Compound (b1-14) 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 or potassium ion, for example) is added and reacted, followed by liquid separation and washing with water, and then from the organic layer, the following general formula (b1-14- 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. Alkoxyalkyl group or halide of alkoxycarbonylalkyl group (for example, general formula “Cl—C (R ⁴⁷ ) (R ⁴⁸ ) —O—R ⁴⁹ ”, “Cl—R ⁵⁰ —C (═O) —O—R) ⁵¹ ″ etc., wherein R ^{47 to} R ⁵¹ are as defined above), and the hydrogen atom of the —OH group of —R ¹⁰ ″ —OH is substituted with the alkoxyalkyl group or alkoxycarbonylalkyl group. Thus, the compound (b1-14) is obtained.

［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。］

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. ]

  As the component (B), one acid generator may be used alone, or two or more acid generators may be used in combination. In addition, when two or more acid generators are used in combination as the component (B), the average 1-octanol / water partition coefficient (LogP) of the cationic components is particularly within the above predetermined range. The acid generator constituting the component (B) is not limited, and those that have been proposed as acid generators for chemically amplified resists can also be used. Onium salt acid generators such as iodonium salts and sulfonium salts, oxime sulfonate acid generators, diazomethane acid generators such as bisalkyl or bisarylsulfonyldiazomethanes, poly (bissulfonyl) diazomethanes, nitrobenzyl sulfonate acids Various generators such as generators, iminosulfonate acid generators and disulfone acid generators are known.

  Examples of the onium salt acid generator include an acid generator represented by the following general formula (b-0).

［式中、Ｒ^５１は、直鎖状、分岐鎖状若しくは環状のアルキル基、または直鎖状、分岐鎖状若しくは環状のフッ素化アルキル基を表し；Ｒ^５２は、水素原子、水酸基、ハロゲン原子、直鎖状若しくは分岐鎖状のアルキル基、直鎖状若しくは分岐鎖状のハロゲン化アルキル基、または直鎖状若しくは分岐鎖状のアルコキシ基であり；Ｒ^５３は置換基を有していてもよいアリール基であり；ｕ”は１〜３の整数である。］

[Wherein R ⁵¹ represents a linear, branched or cyclic alkyl group, or a linear, branched or cyclic fluorinated alkyl group; R ⁵² represents a hydrogen atom, a hydroxyl group or a halogen atom; A linear or branched alkyl group, a linear or branched alkyl halide group, or a linear or branched alkoxy group; R ⁵³ may have a substituent. A good aryl group; u ″ is an integer from 1 to 3.]

In the general formula (b-0), R ⁵¹ represents a linear, branched or cyclic alkyl group, or a linear, branched or cyclic 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 preferably has 4 to 12 carbon atoms, more preferably 5 to 10 carbon atoms, and most preferably 6 to 10 carbon atoms.
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 substituted fluorine atoms to the total number of hydrogen atoms in the alkyl group) is preferably 10 to 100%, more preferably 50 to 100%. Those in which all hydrogen atoms are substituted with fluorine atoms are preferred because the strength of the acid is increased.
R ⁵¹ is most preferably a linear alkyl group or a fluorinated alkyl group.

R ⁵² is a hydrogen atom, a hydroxyl group, a halogen atom, a linear or branched alkyl group, a linear or branched alkyl halide group, or a linear or branched alkoxy group.
In R ⁵² , examples of the halogen atom include a fluorine atom, a bromine atom, a chlorine atom, and an iodine atom, and a fluorine atom is preferable.
In R ⁵² , the alkyl group is linear or branched, and the carbon number thereof is preferably 1 to 5, particularly 1 to 4, and more preferably 1 to 3.
In R ⁵² , the halogenated alkyl group is a group in which part or all of the hydrogen atoms in the alkyl group are substituted with halogen atoms. Examples of the alkyl group herein are the same as the “alkyl group” in R ⁵² . Examples of the halogen atom to be substituted include the same as those described above for the “halogen atom”. 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.
In R ⁵² , the alkoxy group is linear or branched, and the carbon number thereof is preferably 1 to 5, particularly 1 to 4, and more preferably 1 to 3.
Among these, R ⁵² is preferably a hydrogen atom.

R ⁵³ is an aryl group which may have a substituent, and examples of the structure of the basic ring (matrix ring) excluding the substituent include a naphthyl group, a phenyl group, an anthryl group, and the like. From the viewpoint of absorption of exposure light such as ArF excimer laser, a phenyl group is desirable.
Examples of the substituent include a hydroxyl group and a lower alkyl group (straight or branched chain, preferably having 5 or less carbon atoms, particularly preferably a methyl group).
As the aryl group for R ^53, an aryl group having no substituent is more preferable.
u ″ is an integer of 1 to 3, preferably 2 or 3, and particularly preferably 3.

  Preferable examples of the acid generator represented by the general formula (b-0) include the following.

  Examples of other onium salt acid generators represented by the general formula (b-0) include compounds represented by the following general formula (b-1) or (b-2). .

［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；Ｒ^４”は、直鎖状、分岐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; R ⁴ ″ represents a linear, branched or cyclic alkyl group or fluorine; An alkyl group; at least one of R ¹ ″ to R ³ ″ represents an aryl group, and at least one of R ⁵ ″ to R ⁶ ″ represents an aryl group.]

In formula (b-1), R ¹ ″ to R ³ ″ each independently represents an aryl group or an alkyl group. 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.
The aryl group for R ¹ ″ to R ³ ″ 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 alkyl groups, alkoxy groups It may or may not be substituted with a group, a halogen atom or the like. The aryl group is preferably an aryl group having 6 to 10 carbon atoms because it can be synthesized at a low cost. Specific examples include a phenyl group and a naphthyl group.
The 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.
The alkoxy group that may be substituted for the hydrogen atom of the aryl group is preferably an alkoxy group having 1 to 5 carbon atoms, and most preferably a methoxy group or an ethoxy group.
The halogen atom that may be substituted for the hydrogen atom of the aryl group is preferably a fluorine atom.
The alkyl group for R 1 ^{"~R 3",} is not particularly limited, for example, linear C1-10, branched or cyclic alkyl group, and the like. It is preferable that it is C1-C5 from the point which is excellent in resolution. Specific examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an n-pentyl group, a cyclopentyl group, a hexyl group, a cyclohexyl group, a nonyl group, and a decanyl group. A methyl group is preferable because it is excellent in resolution and can be synthesized at low cost.
Among these, R ¹ ″ to R ³ ″ are each 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 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, trifluoromethanesulfonate of (4-hydroxynaphthyl) dimethylsulfonium, its heptaful Propane sulfonate or its nonafluorobutane sulfonate, trifluoromethane sulfonate of dimethylphenylsulfonium, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate, trifluoromethane sulfonate of methyldiphenylsulfonium, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate, (4-Methylphenyl) diphenylsulfonium trifluoromethanesulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate, (4-methoxyphenyl) diphenylsulfonium trifluoromethanesulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate Tri (4-tert-butylphenyl) sulfonium trifluoromethanesulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate, [1- (4-methoxynaphthyl)] diphenylsulfonium trifluoromethanesulfonate, its heptafluoropropane sulfonate or Examples thereof include nonafluorobutanesulfonate, di (1-naphthyl) phenylsulfonium trifluoromethanesulfonate, heptafluoropropanesulfonate, and nonafluorobutanesulfonate. 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, preferably 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 ″, as the number of hydrogen atoms substituted with fluorine atoms increases, the strength of the acid 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 codes 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 an anion moiety (R ⁵¹ SO ₃ ⁻ ) of the onium salt acid generator represented by the general formula (b-0), the general formula (b-1), or (b-2). Fluorinated alkyl sulfonate ions such as an anion moiety (R ^{4 ″} SO ₃ ⁻ ) of an onium salt acid generator represented by formula; an anion moiety represented by the above general formula (b-3) or (b-4) And an anion moiety represented by the general formula “R ² —O—Y ¹ —SO ₃ ^— ”. Among these, a fluorinated alkyl sulfonate ion is preferable, a fluorinated alkyl sulfonate ion having 1 to 4 carbon atoms is more preferable, and a linear perfluoroalkyl sulfonate ion having 1 to 4 carbon atoms is particularly preferable. Specific examples include trifluoromethyl sulfonate ion, heptafluoro-n-propyl sulfonate ion, nonafluoro-n-butyl sulfonate ion, and the like.

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

（式（Ｂ−１）中、Ｒ^３１、Ｒ^３２はそれぞれ独立に有機基を表す。）

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

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

As the organic group for R ^32, a linear, branched, or cyclic alkyl group, aryl group, or cyano group is preferable. As the alkyl group and aryl group for R ^32, the same alkyl groups and aryl groups as those described above for R ³¹ can be used.
R ³² is particularly preferably a cyano group, an alkyl group having 1 to 8 carbon atoms having no substituent, or a fluorinated alkyl group having 1 to 8 carbon atoms.

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

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

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

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

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

In the general formula (B-2), 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 fluorinated by 50% or more, more preferably 70% or more, and even more preferably 90% or more.

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, and most preferably a partially fluorinated alkyl group.
The fluorinated alkyl group in R ³⁵ preferably has 50% or more of the hydrogen atom of the alkyl group fluorinated, more preferably 70% or more, and even more preferably 90% or more. This is preferable because the strength of the acid is increased. 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-nitrobenzenesulfonyloxyimino). Benzyl cyanide, α- (4-nitro-2-trifluoromethylbenzenesulfonyloxyimino) benzyl cyanide, α- (benzenesulfonyloxyimino) -4-chlorobenzyl cyanide, α- (benzenesulfonyloxyimino)- 2,4-dichlorobenzyl cyanide, α- (benzenesulfonyloxyimino) -2,6-dichlorobenzyl cyanide, α- (benzenesulfonyloxyimino) -4-methoxybenzyl cyanide, α- (2-chlorobenzenesulfonyl) Oxyimino) -4-me Xylbenzyl cyanide, α- (benzenesulfonyloxyimino) thien-2-ylacetonitrile, α- (4-dodecylbenzenesulfonyloxyimino) benzyl cyanide, α-[(p-toluenesulfonyloxyimino) -4-methoxy Phenyl] acetonitrile, α-[(dodecylbenzenesulfonyloxyimino) -4-methoxyphenyl] acetonitrile, α- (tosyloxyimino) -4-thienyl cyanide, α- (methylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α -(Methylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (methylsulfonyloxyimino) -1-cycloheptenylacetonitrile, α- (methylsulfonyloxyimino) -1-cyclooctenylacetoni Ril, α- (trifluoromethylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) cyclohexylacetonitrile, α- (ethylsulfonyloxyimino) ethylacetonitrile, α- (propylsulfonyloxyimino) ) Propylacetonitrile, α- (cyclohexylsulfonyloxyimino) cyclopentylacetonitrile, α- (cyclohexylsulfonyloxyimino) cyclohexylacetonitrile, α- (cyclohexylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (ethylsulfonyloxyimino)- 1-cyclopentenylacetonitrile, α- (isopropylsulfonyloxyimino) -1-cyclopentenylacetonitrile , 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- (trifluoromethylsulfonyloxyimino ) Phenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (ethylsulfonyloxyimino) -p-methoxyphenylacetonite Le, alpha-(propylsulfonyl oxyimino)-p-methylphenyl acetonitrile, alpha-like (methylsulfonyloxyimino)-p-bromophenyl acetonitrile.
Further, an oxime sulfonate-based acid generator disclosed in JP-A-9-208554 (paragraphs [0012] to [0014] [chemical formula 18] to [chemical formula 19]), WO2004 / 074242A2 (pages 65 to 85). The oxime sulfonate acid generators disclosed in Examples 1 to 40) of No. 1 can also be suitably used.
Moreover, the following can be illustrated as a suitable thing.

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

  0.5-30 mass parts is preferable with respect to 100 mass parts of (A) component, and, as for content of (B) component in the resist composition for immersion exposure of this invention, 1-10 mass parts is more preferable. 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.

<(A) component>
In the resist composition for immersion exposure according to 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 it can be dissolved in an alkali developer by the action of an acid. It is also possible to use low molecular weight materials whose properties change.
The resist composition for immersion exposure according to the present invention may be a negative resist composition or a positive resist composition.
When the resist composition for immersion exposure according to 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 added to 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. Changes to insoluble in the developer.
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. 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 for immersion exposure of the present invention is a positive resist composition, the solubility of the component (A) in an alkali developer is increased by the action of an acid. That is, the component (A) is an alkali-insoluble one having a so-called acid dissociable, dissolution inhibiting group, and when acid is generated from the component (B) by exposure at the time of resist pattern formation, the acid is dissociated by an acid dissociable, dissolution inhibiting group. (A) component becomes alkali-soluble by dissociating. Therefore, in the formation of the resist pattern, when the resist film obtained by applying the positive resist composition on the support is selectively exposed, the exposed portion turns into alkali-soluble, while the unexposed portion becomes alkaline. Since it remains insoluble and does not change, alkali development can be performed.

  In the resist composition for immersion exposure according to the present invention, the component (A) preferably contains a compound having a fluorine atom and decomposed by the action of an acid to increase the solubility in an alkaline developer. More preferably, it contains the following polymer compound (A2) (hereinafter sometimes referred to as component (A2)). By containing the component (A2), the water repellency of the resist film is improved, and it is suitable as a resist composition for immersion exposure.

<Polymer Compound (A2)>
・ Structural unit (a1 ′)
The polymer compound (A2) is a polymer composed of the structural unit (a1 ′) represented by the following general formula (II).

［式（ＩＩ）中、Ｒは水素原子、ハロゲン原子、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^１〜Ｒ^３は、それぞれ独立してアルキル基またはフッ素化アルキル基である。ただし、前記フッ素化アルキル基は、Ｒ^１〜Ｒ^３が結合している第三級炭素原子に隣接する炭素原子にはフッ素原子が結合していない基であり、Ｒ^１〜Ｒ^３の少なくとも一つは、前記フッ素化アルキル基である。Ｒ^２およびＲ^３は、一つの環構造を形成していてもよい。］

[In formula (II), R represents a hydrogen atom, a halogen atom, a lower alkyl group or a halogenated lower alkyl group; R ^{1 to} R ³ each independently represents an alkyl group or a fluorinated alkyl group. However, the fluorinated alkyl group is a group in which no fluorine atom is bonded to the carbon atom adjacent to the tertiary carbon atom to which R ^{1 to} R ³ are bonded, and at least one of R ^{1 to} R ³ . One is the fluorinated alkyl group. R ² and R ³ may form one ring structure. ]

R in the general formula (II) is a hydrogen atom, a halogen atom, a lower alkyl group or a halogenated lower alkyl group.
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.
Specific examples of the lower alkyl group include lower straight chains such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. Or a branched alkyl group.
Examples of the halogenated lower alkyl group include groups in which part or all of the hydrogen atoms of the lower alkyl group have been substituted with the halogen atoms.
Among these, a hydrogen atom, a fluorine atom, a lower alkyl group or a fluorinated lower alkyl group is preferable, and a hydrogen atom or a methyl group is most preferable from the viewpoint of industrial availability.

In formula (II), R ^{1 to} R ³ are each independently an alkyl group or a fluorinated alkyl group.
Here, the alkyl group may be linear, branched or cyclic.
In the case of a straight chain or branched chain, it preferably has 1 to 5 carbon atoms, more preferably an ethyl group or a methyl group, and most preferably an ethyl group.
In the case of a ring, it is preferably 4 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. Specific examples include groups in which one or more hydrogen atoms have been removed from a polycycloalkane such as monocycloalkane, bicycloalkane, tricycloalkane, and tetracycloalkane. Specific examples include monocycloalkanes such as cyclopentane and cyclohexane, and groups obtained by removing one or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among them, a group obtained by removing one or more hydrogen atoms from adamantane is preferable.

The fluorinated alkyl group is a group in which part or all of the hydrogen atoms in the alkyl group excluding the methyl group are substituted with fluorine atoms. However, it is a group in which no fluorine atom is bonded to the carbon atom adjacent to the tertiary carbon atom to which R ^{1 to} R ³ are bonded. Here, the alkyl group not substituted with a fluorine atom may be linear, branched or cyclic. In the case of a linear or branched chain, the number of carbon atoms is preferably 2 to 7, more preferably 2 to 5, and particularly preferably an n-butyl group. In the case of a ring, the same as those described above for the “alkyl group” can be mentioned. The carbon atom to which the fluorine atom in the fluorinated alkyl group is bonded is preferably separated from the tertiary carbon atom to which R ^{1 to} R ³ are bonded.
Preferable examples of such a fluorinated alkyl group include 4,4,4-trifluoro-n-butyl group.
In formula (II), at least one of R ^{1 to} R ³ is the fluorinated alkyl group. And any one of R ^{1 to} R ³ is preferably the fluorinated alkyl group, and the remaining two are preferably alkyl groups.

In the formula (II), R ² and R ³ may be bonded to each other to form one ring structure. When R ² and R ³ are bonded to each other to form one ring structure, R ² and R ³ are preferably not fluorinated, in which case R ¹ is the fluorinated alkyl group. It becomes. Examples of the cyclic alkyl group formed by R ² and R ³ at this time include the same as those described above for the “alkyl group”.

  As a high molecular compound (A2), the polymer shown to the following general formula (A-2-1) can be illustrated as a most preferable thing (In formula, R is the same as that of R in the said general formula (II). ).

［式中、Ｒは前記一般式（ＩＩ）中のＲと同様である。］

[Wherein, R is the same as R in the general formula (II). ]

  The polymer compound (A2) is a compound represented by the following general formula (I) as a monomer, for example, 2,2-azobisisobutyronitrile (AIBN), 2,2′-azobis (2,4- It can be produced by polymerization by a conventionally known radical polymerization using a radical polymerization initiator such as dimethylvaleronitrile.

［式（Ｉ）中、Ｒ、Ｒ^１〜Ｒ^３は、前記一般式（ＩＩ）におけるＲ、Ｒ^１〜Ｒ^３と同様である。］

Wherein ^{(I), R, R 1} ~R 3 is, ^R in Formula ^(II), is the same as R 1 to R ^3. ]

Although the mass mean molecular weight (Mw) (polystyrene conversion reference | standard by gel permeation chromatography) of a high molecular compound (A2) is not specifically limited, 2000-50000 are preferable, 3000-30000 are more preferable, 5000- 20000 is most preferred. When it is smaller than the upper limit of this range, it has sufficient solubility in a resist solvent to be used as a resist. When it is larger than the lower limit of this range, dry etching resistance and resist pattern cross-sectional shape are good.
Moreover, 1.0-5.0 are preferable and, as for the dispersity (Mw / Mn) of a high molecular compound (A2), 1.0-3.0 are more preferable. Mn represents a number average molecular weight.

<(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.
Component (A1) contains a structural unit (a1) derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group, a structural unit (a2) derived from an acrylate ester containing a lactone-containing cyclic group, and a polar group It is preferable to contain a copolymer (A1) containing a structural unit (a3) derived from an acrylate ester containing an 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.
The “alkyl group” includes linear, branched and cyclic monovalent saturated hydrocarbon groups unless otherwise specified.
The “lower alkyl group” is an alkyl group having 1 to 5 carbon atoms.
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.
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. Of these, a hydrogen atom or a methyl group is particularly preferred from the viewpoint of industrial availability.

・ 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.
Generally, 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 a carbon atom and a hydrogen atom (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 that 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. More specifically, 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 are exemplified. .
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 each} represents an alkyl group (which may be linear or branched, and preferably has 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, the acid acts to break the bond between the acetal acid dissociable, dissolution inhibiting group and the oxygen atom to which the acetal acid dissociable, dissolution inhibiting group is bonded.
Examples of the acetal type acid dissociable, dissolution inhibiting group include a group represented by the following general formula (p1).

［式中、Ｒ^１’，Ｒ^２’はそれぞれ独立して水素原子または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 and Y are the same as described 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 a group excluding a hydrogen atom. Specific examples include monocycloalkanes such as cyclopentane and cyclohexane, and groups obtained by removing one or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among them, a group obtained by removing one or more hydrogen atoms from adamantane is preferable.
In the above formula, 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- to 7-membered ring, and more preferably a 4- to 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 a group in which two or more hydrogen atoms are removed is used as the aliphatic cyclic group. Except for the above, the same “aliphatic cyclic group” as described above 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. .

  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. ]

Wherein, X 'include those of the same tertiary alkyl ester-type acid dissociable, dissolution inhibiting groups as those described above for X ^{1.
R 1 ', R 2',} n, as the Y, respectively, ^{R 1} in the general formula listed in the description of "acetal-type acid dissociable, dissolution inhibiting group" described above ^{(p1) ', R 2'} , n, Y The same thing is mentioned.
The Y ^2, the same groups as those described above for ^{Y 2} in the general formula (a1-0-2).

  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 formulas (a1-1-1) to (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.

In the component (A1), as the structural unit (a1), one type of structural unit may be used alone, or two or more types may be used in combination.
When the component (A1) contains the structural unit (a1), the proportion of the structural unit (a1) in the component (A1) is preferably 10 to 80 mol% with respect to all the structural units constituting the component (A1). 20-70 mol% is more preferable, and 25-50 mol% is further 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)
In the present invention, the component (A1) preferably has a structural unit (a2) derived from an acrylate ester containing a lactone-containing cyclic group in addition to the structural unit (a1).
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, and when it is only the lactone ring, it is called a monocyclic group, and when it has another ring structure, it is called a polycyclic group regardless of the structure.
The lactone cyclic group of the structural unit (a2) has a high affinity for a resist film support or a developer containing water when the component (A1) is used for forming a resist film. 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、炭素数１〜５のアルコキシ基または−ＣＯＯＲ”であり、前記Ｒ”は水素原子、または炭素数１〜１５の直鎖状、分岐鎖状もしくは環状のアルキルキル基であり、ｍは０または１の整数であり、Ａ”は酸素原子もしくは硫黄原子を含んでいてもよい炭素数１〜５のアルキレン基、酸素原子または硫黄原子である。］

[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, an alkoxy group having 1 to 5 carbon atoms, or —COOR ″, wherein R ″ is A hydrogen atom or a linear, branched or cyclic alkylalkyl group having 1 to 15 carbon atoms, m is an integer of 0 or 1, and A ″ is a carbon which may contain an oxygen atom or a sulfur atom. It is an alkylene group of formulas 1 to 5, an oxygen atom or a sulfur 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).
When R ″ is a linear or branched alkyl group, it preferably has 1 to 10 carbon atoms, and more preferably 1 to 5 carbon atoms.
When R ″ is a cyclic alkyl group, it preferably has 3 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. Specifically, a fluorine atom or fluorine atom A group in which one or more hydrogen atoms are removed from a polycycloalkane such as monocycloalkane, bicycloalkane, tricycloalkane, tetracycloalkane, etc., which may or may not be substituted with an alkyl group. Specific examples thereof include monocycloalkanes such as cyclopentane and cyclohexane, groups obtained by removing one or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Can be mentioned.
In general formulas (a2-1) to (a2-5), R ′ is preferably a hydrogen atom in view of industrial availability.
Specific examples of the alkylene group having 1 to 5 carbon atoms that may contain an oxygen atom or sulfur atom of A ″ include a methylene group, an ethylene group, an n-propylene group, an isopropylene group, —O—CH ₂ —. _{, -CH 2 -O-CH 2 -} , - S-CH 2 -, - CH 2 -S-CH 2 - , and the like.
Below, the specific structural unit of the said general formula (a2-1)-(a2-5) is illustrated.

In the copolymer (A1), as the structural unit (a2), one type may be used alone, or two or more types may be used in combination.
As the structural unit (a2), at least one selected from the group consisting of structural units represented by the general formulas (a2-1) to (a2-5) is preferable, and the general formulas (a2-1) to (a2) -3) At least 1 sort (s) selected from the group which consists of a structural unit represented by 3) is more preferable. Among them, chemical formulas (a2-1-1), (a2-1-2), (a2-2-1), (a2-2-2), (a2-2-9), (a2-2-10) ), (A2-3-1), (a2-3-2), (a2-3-9) and (a2-3-10) at least one selected from the group consisting of structural units It is preferable to use it.

  5-60 mol% is preferable with respect to the sum total of all the structural units which comprise a copolymer (A1), and the ratio of the structural unit (a2) in a copolymer (A1) is 10-50 mol% more. Preferably, 20-50 mol% is more preferable. 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 the same as above, j is an integer of 1 to 3, k is an integer of 1 to 3, t 'is an integer of 1 to 3, and l is an integer of 1 to 5) And s is an integer of 1 to 3.)

In formula (a3-1), j is preferably 1 or 2, and more preferably 1. When j is 2, it is preferable that the hydroxyl group is bonded to the 3rd and 5th positions of the adamantyl group. When j is 1, it is preferable that the hydroxyl group is bonded to the 3-position of the adamantyl group.
j is preferably 1, and a hydroxyl group bonded to the 3rd position of the adamantyl group is particularly preferred.

  In formula (a3-2), k is preferably 1. The cyano group is preferably bonded to the 5th or 6th position of the norbornyl group.

  In formula (a3-3), t ′ is preferably 1. l is preferably 1. s is preferably 1. These preferably have a 2-norbornyl group or a 3-norbornyl group bonded to the terminal of the carboxy group of acrylic acid. The fluorinated alkyl alcohol is preferably bonded to the 5th or 6th position of the norbornyl group.

As the structural unit (a3), one type may be used alone, or two or more types may be used in combination.
In the copolymer (A1), the proportion of the structural unit (a3) is preferably 5 to 50% by mole, and 5 to 40% by mole with respect to all the structural units constituting the copolymer (A1). More preferably, 5-25 mol% is further more preferable.

・ Structural unit (a4)
The copolymer (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 that is not classified into the structural units (a1) to (a3) described above, and is for ArF excimer laser and 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。）

(In the formula, R is as defined above.)

  When the structural unit (a4) is contained in the copolymer (A1), the structural unit (a4) is contained in an amount of 1 to 30 mol% based on the total of all the structural units constituting the copolymer (A1). It is preferable to make it contain, and it is more preferable to contain 10-20 mol%.

  In the present invention, the copolymer (A1) is a copolymer having the structural units (a1), (a2) and (a3), and examples of the copolymer include the structural units (a1), ( Examples thereof include a copolymer comprising a2) and (a3), a copolymer comprising the structural units (a1), (a2), (a3) and (a4).

In the component (A), as the copolymer (A1), one type may be used alone, or two or more types may be used in combination.
In the present invention, as the copolymer (A1), those containing the following combinations of structural units are particularly preferable.

［式中、Ｒは前記と同じであり、複数のＲはそれぞれ同じであっても異なっていてもよい。Ｒ^１０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 ¹⁰ is a lower alkyl group. ]

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

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

In formula (A1-11), the lower alkyl group for R ^{10 is the same as} the lower alkyl group for R, preferably a methyl group or an ethyl group, and most preferably an ethyl group.
In formula (A1-21), the lower alkyl group for R ^{20 is the same as} the lower alkyl group for R, preferably a methyl group or an ethyl group, and most preferably a methyl group.
In formula (A1-21), A ″ is the same as A ″ in formula (a2-2), and is preferably an oxygen atom, a methylene group, or an ethylene group.

The copolymer (A1) can be obtained by polymerizing a monomer for deriving each structural unit by a known radical polymerization using a radical polymerization initiator such as azobisisobutyronitrile (AIBN). it can.
In the copolymerization (A1), a chain transfer agent such as HS—CH ₂ —CH ₂ —CH ₂ —C (CF ₃ ) ₂ —OH is used in combination in the above polymerization. In addition, a —C (CF ₃ ) ₂ —OH group may be introduced at the terminal. 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 copolymer (A1) is not particularly limited, but is preferably 2000 to 50000, more preferably 3000 to 30000, and 5000 to 20000 is most preferred. When it is smaller than the upper limit of this range, it has sufficient solubility in a resist solvent to be used as a resist. When it is larger than the lower limit of this range, 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.

<Optional component>
The resist composition for immersion exposure according to the present invention further includes, as an optional component, a nitrogen-containing organic compound (D) (hereinafter referred to as the component (D)) in order to improve the resist pattern shape, the stability with time, and the like. It is preferable to contain.
Since a wide variety of components (D) have already been proposed, any known one may be used. Cyclic amines, aliphatic amines, particularly secondary aliphatic amines and tertiary fats may be used. Group amines are preferred. Here, the 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. Of these, alkyl alcohol amines and trialkyl amines are preferred. Among the alkyl alcohol amines, triethanolamine is most preferable, and among the trialkylamines, tri-n-pentylamine and tri-n-octylamine are 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.

In the resist composition for immersion exposure according to the present invention, an organic carboxylic acid, a phosphorus oxoacid, and a phosphorus oxoacid can be used as optional components for the purpose of preventing sensitivity deterioration and improving the resist pattern shape, stability over time, etc. At least one compound (E) selected from the group consisting of derivatives thereof (hereinafter referred to as component (E)) can be contained.
Examples of the organic carboxylic acid include acetic acid, malonic acid, citric acid, malic acid, succinic acid, benzoic acid, and salicylic acid. Among these, salicylic acid is particularly preferable.
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 the phosphinic acid derivatives include phosphinic acid esters such as phenylphosphinic acid.
These may be used alone or in combination of two or more.
(E) A component is used in the ratio of 0.01-5.0 mass parts per 100 mass parts of (A) component.

  The resist composition for immersion exposure according to the present invention further contains miscible additives, for example, an additional resin for improving the performance of the resist film, a surfactant for improving the coating property, a dissolution agent, if desired. An inhibitor, a plasticizer, a stabilizer, a colorant, an antihalation agent, a dye, and the like can be appropriately added and contained.

<(S) component>
The resist composition for immersion exposure according to the present invention can be produced by dissolving a 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; Monohydric alcohols; compounds having an ester bond, such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, dipropylene glycol monoacetate, monomethyl ether, monoethyl of the polyhydric alcohols or compound having the 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.
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 3-15% by mass.

In the resist composition for immersion exposure according to the present invention, when the component (A) contains a compound having a fluorine atom as in the structural unit (a1 ′), compared with the case where it does not contain a fluorine atom, A resist film formed using a positive resist composition has high hydrophobicity, and is therefore more suitable for immersion exposure.
The resist composition for immersion exposure according to the present invention also has good lithography properties such as sensitivity, resolution and etching resistance. For example, by using the resist composition for immersion exposure according to the present invention, a fine resist pattern having a line width of a line and space (L / S) pattern of 120 nm or less can be formed. In addition, the resist composition for immersion exposure of the present invention has excellent etching resistance, particularly when it has an aliphatic cyclic group, and the etching resistance is such that the aliphatic cyclic group is a polycyclic group. Especially good in some cases.

The resist composition for immersion exposure according to the present invention has various excellent characteristics as described above, and in particular, an immersion solution using water as an immersion solvent from the viewpoint of a small amount of substance elution with respect to water. Suitable for exposure.
As described above, in immersion exposure, during exposure, a portion between a lens, which is conventionally filled with an inert gas such as air or nitrogen, and a resist film on the wafer is refracted larger than the refractive index of air. It is the method which has the process of performing exposure (immersion exposure) in the state satisfy | filled with the solvent (immersion medium) which has a rate.
In immersion exposure, when the resist film and the immersion solvent come into contact with each other, elution (substance elution) of substances ((B) component, (D) component, etc.) in the resist film into the immersion solvent occurs. Substance elution causes phenomena such as alteration of the resist layer and change in the refractive index of the immersion solvent, thereby deteriorating the lithography properties. The amount of this substance elution is affected by the characteristics of the resist film surface (for example, hydrophilicity / hydrophobicity) and has a high correlation with the 1-octanol / water partition coefficient of the cation component of the component (B).
According to the resist composition for immersion exposure of the present invention, the elution of substances during immersion exposure is suppressed by setting the 1-octanol / water partition coefficient of the cation component of component (B) to 7.0 to 9.5. it can.

As described above, in the present invention, substance elution into the immersion solvent, particularly water, is suppressed. Therefore, in immersion exposure, by using the resist composition for immersion exposure according to the present invention, it is possible to suppress alteration of the resist film and change in the refractive index of the immersion solvent. Therefore, the shape of the resist pattern to be formed is improved, for example, by suppressing fluctuations in the refractive index of the immersion solvent.
In addition, contamination of the lens of the exposure apparatus can be reduced, and therefore protection measures for these can be omitted, contributing to simplification of the process and the exposure apparatus.
Further, as described above, when performing immersion exposure using a scanning immersion exposure machine as described in Non-Patent Document 1, the immersion medium moves following the movement of the lens. Although followability is required, in the present invention, the resist film has high hydrophobicity and high water followability. In addition, the resist composition for immersion exposure according to the present invention has good lithography characteristics, and can be used to form a resist pattern without any practical problems when used as a resist in immersion exposure.
As described above, the resist composition for immersion exposure according to the present invention has good lithography characteristics (sensitivity, resolution, etching resistance, etc.) that are usually required, and characteristics required for resist materials in immersion exposure. (Hydrophobic property, substance elution suppression ability, water followability, etc.) are also excellent. Therefore, the resist composition for immersion exposure according to the present invention is suitable for immersion exposure.

≪Resist pattern formation method≫
Next, the resist pattern forming method of the present invention will be described.
The resist pattern forming method of this aspect includes a step of forming a resist film on a support using the resist composition for immersion exposure according to the present invention, a step of exposing the resist film, and developing the resist film. Forming a resist pattern.
The support is not particularly limited, and a conventionally known one can be used, and examples thereof include a substrate for electronic components and a substrate on which a predetermined wiring pattern is formed. More specifically, a silicon substrate, a metal substrate such as copper, chromium, iron, and aluminum, a glass substrate, and the like can be given. As a material for the wiring pattern, for example, copper, aluminum, nickel, gold or the like can be used.
Further, the support may be a substrate in which an inorganic and / or organic film is provided on the above-described substrate. An inorganic antireflection film (inorganic BARC) is an example of the inorganic film. Examples of the organic film include an organic antireflection film (organic BARC).
The resist pattern forming method of the present invention can be performed, for example, as follows.
That is, first, the resist composition for immersion exposure according to the present invention is applied onto a substrate such as a silicon wafer with a spinner or the like, and pre-baked (post-apply bake (PAB)) 40 at a temperature of 80 to 150 ° C. The resist film is formed by applying for 120 seconds, preferably 60 to 90 seconds. The resist film is selectively exposed using a predetermined exposure light source with or without a desired mask pattern. That is, exposure is performed through the mask pattern, or drawing is performed by direct irradiation with an electron beam without using the mask pattern.
After the selective exposure, heat treatment (post-exposure baking (PEB)) is performed for 40 to 120 seconds, preferably 60 to 90 seconds, at a temperature of 80 to 150 ° C. Subsequently, this is developed using an alkali developer, for example, an aqueous solution of 0.1 to 10% by mass of tetramethylammonium hydroxide (TMAH), and preferably rinsed with pure water. The water rinsing can be performed, for example, by dropping or spraying water on the substrate surface while rotating the substrate to wash away the developer on the substrate and the resist composition for immersion exposure dissolved by the developer. And a resist pattern can be formed by drying.
An organic or inorganic antireflection film may be provided between the substrate and the coating layer of the resist composition.
The wavelength used for the exposure is not particularly limited, and includes KrF excimer laser, ArF 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. Among these, the resist composition for immersion exposure according to the present invention is particularly effective for an ArF excimer laser.

<Immersion exposure>
As described above, the resist composition for immersion exposure of the present invention can be suitably used for immersion exposure.
In the immersion exposure, the resist pattern can be formed by performing exposure by immersion exposure, that is, performing a step of immersion exposure of the resist film in the step of exposing the resist film in the resist pattern forming method.
The step of immersing and exposing the resist film can be performed, for example, as follows.
First, the space between the resist film obtained as described above and the lens at the lowest position of the exposure apparatus is filled with a solvent (immersion medium) having a refractive index larger than the refractive index of air. Exposure (immersion exposure) is performed with or without a mask pattern.
The wavelength used for exposure is not particularly limited, and the same ones as mentioned above can be used.

As the immersion medium, a solvent having a refractive index larger than the refractive index of air and smaller than the refractive index of the resist film formed using the resist composition for immersion exposure of the present invention is preferable. The refractive index of such a solvent is not particularly limited as long as it is within the above range.
Examples of the solvent having a refractive index larger than the refractive index of air and smaller than the refractive index of the resist film include water, a fluorine-based inert liquid, and a silicon-based solvent.
Specific examples of the fluorine-based inert liquid include a fluorine-based compound such as C ₃ HCl ₂ F ₅ , C ₄ F ₉ OCH ₃ , C ₄ F ₉ OC ₂ H ₅ , and C ₅ H ₃ F ₇ as a main component. Examples thereof include liquids, and those having a boiling point of 70 to 180 ° C are preferable, and those having a boiling point of 80 to 160 ° C are more preferable. It is preferable that the fluorine-based inert liquid has a boiling point in the above range since the medium used for immersion can be removed by a simple method after the exposure is completed.
As the fluorine-based inert liquid, a perfluoroalkyl compound in which all hydrogen atoms of the alkyl group are substituted with fluorine atoms is particularly preferable. Specific examples of the perfluoroalkyl compound include a perfluoroalkyl ether compound and a perfluoroalkylamine compound.
More specifically, examples of the perfluoroalkyl ether compound include perfluoro (2-butyl-tetrahydrofuran) (boiling point 102 ° C.). Examples of the perfluoroalkylamine compound include perfluorotributylamine ( Boiling point of 174 ° C.).

  Since the resist composition for immersion exposure of the present invention is not particularly adversely affected by water and is excellent in sensitivity and resist pattern shape, water is preferably used as a solvent having a refractive index larger than that of air. Water is also preferable from the viewpoints of cost, safety, environmental problems, and versatility.

  Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited to the following examples.

(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 (B) -10>

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.

(Synthesis Example 3)
<Synthesis of Compound (B) -9>

In Synthesis Example 2, the reaction was carried out 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 (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.

[Examples 1-2, Comparative Examples 1-8]
Each component shown in Table 1 was mixed and dissolved to prepare a positive resist composition.

Here, the unit of the blending amount shown in [] in Table 2 is part by mass. Moreover, the symbol in Table 2 has the following meaning.
(A) -1: a polymer represented by the following chemical formula (A) -1.
(A) -2: Resin represented by the following chemical formula (A) -2.
(B) -1: a compound represented by the following chemical formula (B) -1.
(B) -2: A compound represented by the following chemical formula (B) -2.
(B) -3: A compound represented by the following chemical formula (B) -3.
(B) -4: A compound represented by the following chemical formula (B) -4.
(B) -5: A compound represented by the following chemical formula (B) -5.
(B) -6: A compound represented by the following chemical formula (B) -6.
(B) -7: A compound represented by the following chemical formula (B) -7.
(B) -8: A compound represented by the following chemical formula (B) -8.
(B) -9: A compound represented by the following chemical formula (B) -9.
(B) -10: A compound represented by the following chemical formula (B) -10.
(S) -1: PGMEA / PGME = 6/4 (mass ratio) mixed solvent.

  The (A) -1 was copolymerized by a known dropping polymerization method using a monomer for deriving each structural unit. The weight average molecular weight (Mw) was 7000, and the dispersity (Mw / Mn) was 1.8. Moreover, the compounding quantity of (B) component is equimolar.

<Measurement of eluate>
An organic antireflection film composition “ARC-29A” (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 thickness of 77 nm was formed. On the antireflection film, the resist compositions of Examples 1 and 2 and Comparative Examples 1 to 8 were respectively applied using a spinner, prebaked (PAB) at 115 ° C. for 60 seconds on a hot plate, and dried. As a result, a resist film having a thickness of 150 nm was formed.
Next, using VRC310S (trade name, manufactured by SS Co., Ltd.), 1 drop (50 μl) of pure water is moved at room temperature at a constant linear velocity so as to draw a circle from the center of the wafer at room temperature. (The total contact area of the resist film in contact with the droplet was 221.56 cm ² ).
Thereafter, the droplets were collected and analyzed by an analyzer Agilent-HP1100 LC-MSD (trade name, manufactured by Agilent Technologies), and the elution amount of the cation part (PAG +) of the component (B) before exposure (× 10 ⁻¹² mol / cm ² · s). These results are shown in Table 2.

<Calculation of 1-octanol / water partition coefficient (LogP)>
The LogP value was calculated using calculation software CAChe manufactured by Fujitsu.

  From the results of Table 3, in Examples 1 and 2, the elution amount of the cation part of the component (B) in the immersion medium (water) before and after the exposure processing is reduced, and the substance elution suppression during the immersion exposure is reduced. It was confirmed that the effect was high. Since the resist composition for immersion exposure of the present invention has little substance elution into the immersion medium (water), good lithography characteristics can be obtained.

<Lithography characteristics evaluation>
"Resolution and sensitivity"
After adding 1.2 parts by mass of tri-n-pentylamine as a quencher to each of the resist compositions of Examples 1-2 and Comparative Examples 1-8, a resist pattern was formed by the following procedure.
An organic antireflection film composition “ARC-29A” (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 thickness of 77 nm was formed. On the antireflection film, the resist compositions of Examples 1 and 2 and Comparative Examples 1 to 8 were respectively applied using a spinner, prebaked (PAB) at 115 ° C. for 60 seconds on a hot plate, and dried. As a result, a resist film having a thickness of 150 nm was formed.
An ArF excimer laser (193 nm) is selected for the resist film through a mask pattern using an ArF exposure apparatus NSR-S302A (Nikon Corp .; NA (numerical aperture) = 0.60, 2/3 annular illumination). Irradiated. Then, PEB processing is performed at 115 ° C. for 60 seconds, and further development processing is performed at 23 ° C. with an aqueous 2.38 mass% tetramethylammonium hydroxide (TMAH) solution for 30 seconds, and then pure water is used for 30 seconds. By rinsing with water and performing spin-drying, a line-and-space (1: 1) resist pattern (hereinafter referred to as an L / S pattern) having a line width of 120 nm and a pitch of 240 nm could be formed.

Claims (8)

A resist composition containing a base material 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,
1-octanol / water partition coefficient of the cation component of the acid generator component (B) is 7.0 to 11.0 ,
When the cation component of the acid generator component (B) contains an alkoxycarbonylalkyloxy group, the number of the alkoxycarbonyloxy group is one (provided that the cation component of the acid generator component (B) is represented by the following chemical formula: the resist composition comprising in formula except cations) that.

The resist composition for immersion exposure according to claim 1, wherein the compound constituting the acid generator component (B) is represented by the following general formula (b1-14).

[Wherein R ⁷ "~ R ⁹ Each independently represents an aryl or alkyl group; R ⁷ "~ R ⁹ Any two of them may be joined together to form a ring with the sulfur atom in the formula; R ⁷ "~ R ⁹ Is a substituted aryl group in which one or all of the hydrogen atoms are substituted with an alkoxyalkyloxy group or an alkoxycarbonylalkyloxy group; X ⁻ Is an anion. ] It said base component (A), according to claim 1 or 2 resist composition according by the action of an acid is a base component which exhibits increased solubility in an alkali developing solution. The base material component (A) contains a resin component (A1) whose solubility in an alkaline developer is increased by the action of an acid, and the resin component (A1) contains an acid dissociable, dissolution inhibiting group. The resist composition for immersion exposure according to claim 3 , comprising a structural unit (a1) derived from The resist composition for immersion exposure according to claim 4, wherein the resin component (A1) further has a structural unit (a2) derived from an acrylate ester containing a lactone-containing cyclic group. The resist composition for immersion exposure according to claim 4 or 5, wherein the resin component (A1) further comprises a structural unit (a3) derived from an acrylate ester containing a polar group-containing aliphatic hydrocarbon group. Furthermore, the resist composition for immersion exposure as described in any one of Claims 4-6 containing a nitrogen-containing organic compound (D). Forming a resist film on a substrate using the resist composition according to any one of claims 1 to 7 conducting exposure of the resist film, and the resist film was alkali developed A resist pattern forming method including a step of forming a resist pattern.