JP6123553B2 - Salt, resist composition and method for producing resist pattern - Google Patents

Description

  The present invention relates to a salt useful as an acid generator, a resist composition, and a method for producing a resist pattern.

The resist composition used for semiconductor microfabrication contains a salt for an acid generator. For example, Patent Document 1 discloses a salt represented by the following formula as a salt for such an acid generator.

JP2012-72109A

  Conventionally known resist compositions may not always have sufficient pattern collapse resistance (PCM) during the production of resist patterns.

［式（Ｉ）中、
Ｑ^１及びＱ^２は、それぞれ独立に、フッ素原子又は炭素数１〜６のペルフルオロアルキル基を表す。
Ｌ^１は、カルボニル基又は−ＣＦ_２−を表す。
Ｘ^０は、単結合、置換基を有していてもよい炭素数１〜１４の２価の飽和炭化水素基又は式（ａ−１）で表される基を表す。

（式（ａ−１）中、
ｃは、０又は１を表す。
Ｘ¹⁰及びＸ^1１は、それぞれ独立に、酸素原子、カルボニル基、カルボニルオキシ基又はオキシカルボニル基を表す。
Ａ¹⁰、Ａ^1１及びＡ¹²は、それぞれ独立に、置換基を有していてもよい炭素数１〜１２の２価の飽和炭化水素基を表す。
＊は炭素原子との結合手である。）
Ｘ^１は、−（ＣＨ_２）_ａ−Ｏ−（ＣＨ_２）_ｂ−^＊１、−（ＣＨ_２）_ａ−Ｏ−ＣＯ−^＊１、−（ＣＨ_２）_ａ−Ｏ−ＣＨ_２−ＣＯ−Ｏ−^＊１又は−（ＣＨ_２）_ａ−ＮＲ^２−（ＣＨ_２）_ｂ−^＊１を表す。＊１はＷ^１との結合手を表す。
ａは、０〜６の整数を表す。
ｂは、０又は１を表す。
Ｒ^２は、水素原子又は炭素数１〜６のアルキル基を表す。
Ｗ^１は、炭素数３〜３６の１価の脂環式炭化水素基を表し、該脂環式炭化水素基を構成するメチレン基は、酸素原子、硫黄原子、カルボニル基又はスルホニル基で置き換わっていてもよく、該脂環式炭化水素基に含まれる水素原子は、ヒドロキシ基、炭素数１〜１２のアルキル基、炭素数１〜１２のアルコキシ基、炭素数３〜１８の１価の脂環式炭化水素基又は炭素数６〜１４の１価の芳香族炭化水素基で置換されていてもよい。
Ｚ^＋は、有機カチオンを表す。］ The present invention includes the following inventions.
[1] A salt represented by the formula (I).

[In the formula (I),
Q ¹ and Q ² each independently represents a fluorine atom or a C 1-6 perfluoroalkyl group.
L ¹ represents a carbonyl group or —CF ₂ —.
X ⁰ represents a single bond, a divalent saturated hydrocarbon group having 1 to 14 carbon atoms which may have a substituent, or a group represented by the formula (a-1).

(In the formula (a-1),
c represents 0 or 1;
X ¹⁰ and X ¹¹ each independently represent an oxygen atom, a carbonyl group, a carbonyloxy group or an oxycarbonyl group.
A ¹⁰ , A ¹¹ and A ¹² each independently represent a C 1-12 divalent saturated hydrocarbon group which may have a substituent.
* A bond with a carbon atom. )
X ¹ represents — (CH ₂ ) _a —O— (CH ₂ ) _b — ^{* 1} , — (CH ₂ ) _a —O—CO— ^{* 1} , — (CH ₂ ) _a —O—CH ₂ —CO—. ^{O-* 1} or _- represents a _{^{* 1 - (CH 2) a}} -NR 2 - (CH 2) b. * 1 represents a bond to ^{W 1.}
a represents an integer of 0 to 6.
b represents 0 or 1.
R ² represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
W ¹ represents a monovalent alicyclic hydrocarbon group having 3 to 36 carbon atoms, and the methylene group constituting the alicyclic hydrocarbon group is replaced with an oxygen atom, a sulfur atom, a carbonyl group or a sulfonyl group. The hydrogen atom contained in the alicyclic hydrocarbon group may be a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or a monovalent alicyclic ring having 3 to 18 carbon atoms. It may be substituted with a formula hydrocarbon group or a monovalent aromatic hydrocarbon group having 6 to 14 carbon atoms.
Z ⁺ represents an organic cation. ]

[2] The salt according to [1], wherein W ^{1 in the} formula (I) is a 2-oxoadamantyl group, an adamantyl group having 1 to 12 carbon atoms or an hydroxy group.
[3] An acid generator containing the salt according to [1] or [2].
[4] The acid generator according to [3], further comprising an acid generator other than the salt according to [1] or [2].
[5] A resist composition comprising the acid generator according to [4] or [5] and a resin having an acid labile group.
[6] A step of applying the resist composition according to (1) [5] on a substrate,
(2) The process of drying the composition after application | coating and forming a composition layer,
(3) a step of exposing the composition layer;
(4) a step of heating the composition layer after exposure, and (5) a step of developing the composition layer after heating,
A method for producing a resist pattern including:

  The resist composition of the present invention can produce a resist pattern with good pattern collapse resistance (PCM).

［式（Ｉ）中、
Ｑ^１及びＱ^２は、それぞれ独立に、フッ素原子又は炭素数１〜６のペルフルオロアルキル基を表す。
Ｌ^１は、カルボニル基又は−ＣＦ_２−を表す。
Ｘ^０は、単結合、置換基を有していてもよい炭素数１〜１４の２価の飽和炭化水素基又は式（ａ−１）で表される基を表す。

（式（ａ−１）中、
ｂは、０又は１を表す。
Ｘ¹⁰及びＸ^1１は、それぞれ独立に、酸素原子、カルボニル基、カルボニルオキシ基又はオキシカルボニル基を表す。
Ａ¹⁰、Ａ^1１及びＡ¹²は、それぞれ独立に、置換基を有していてもよい炭素数１〜１２の２価の飽和炭化水素基を表す。
＊は炭素原子との結合手である。）
Ｘ^１は、−（ＣＨ_２）_ａ−Ｏ−（ＣＨ_２）_ｂ−^＊１、−（ＣＨ_２）_ａ−Ｏ−ＣＯ−^＊１、−（ＣＨ_２）_ａ−Ｏ−ＣＨ_２−ＣＯ−Ｏ−^＊１又は−（ＣＨ_２）_ａ−ＮＲ^２−（ＣＨ_２）_ｂ−^＊１を表す。＊１はＷ^１との結合手を表す。
ａは、０〜６の整数を表す。
ｂは、０又は１を表す。
Ｒ^２は、水素原子又は炭素数１〜６のアルキル基を表す。
Ｗ^１は、炭素数３〜３６の１価の脂環式炭化水素基を表し、該脂環式炭化水素基を構成するメチレン基は、酸素原子、硫黄原子、カルボニル基又はスルホニル基で置き換わっていてもよく、該脂環式炭化水素基に含まれる水素原子は、ヒドロキシ基、炭素数１〜１２のアルキル基、炭素数１〜１２のアルコキシ基、炭素数３〜１８の１価の脂環式炭化水素基又は炭素数６〜１４の１価の芳香族炭化水素基で置換されていてもよい。
Ｚ^＋は、有機カチオンを表す。］ <Salt represented by formula (I)>
The salt of the present invention is a salt represented by the formula (I) (hereinafter sometimes referred to as “salt (I)”).

[In the formula (I),
Q ¹ and Q ² each independently represents a fluorine atom or a C 1-6 perfluoroalkyl group.
L ¹ represents a carbonyl group or —CF ₂ —.
X ⁰ represents a single bond, a divalent saturated hydrocarbon group having 1 to 14 carbon atoms which may have a substituent, or a group represented by the formula (a-1).

(In the formula (a-1),
b represents 0 or 1.
X ¹⁰ and X ¹¹ each independently represent an oxygen atom, a carbonyl group, a carbonyloxy group or an oxycarbonyl group.
A ¹⁰ , A ¹¹ and A ¹² each independently represent a C 1-12 divalent saturated hydrocarbon group which may have a substituent.
* A bond with a carbon atom. )
X ¹ represents — (CH ₂ ) _a —O— (CH ₂ ) _b — ^{* 1} , — (CH ₂ ) _a —O—CO— ^{* 1} , — (CH ₂ ) _a —O—CH ₂ —CO—. ^{O-* 1} or _- represents a _{^{* 1 - (CH 2) a}} -NR 2 - (CH 2) b. * 1 represents a bond to ^{W 1.}
a represents an integer of 0 to 6.
b represents 0 or 1.
R ² represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
W ¹ represents a monovalent alicyclic hydrocarbon group having 3 to 36 carbon atoms, and the methylene group constituting the alicyclic hydrocarbon group is replaced with an oxygen atom, a sulfur atom, a carbonyl group or a sulfonyl group. The hydrogen atom contained in the alicyclic hydrocarbon group may be a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or a monovalent alicyclic ring having 3 to 18 carbon atoms. It may be substituted with a formula hydrocarbon group or a monovalent aromatic hydrocarbon group having 6 to 14 carbon atoms.
Z ⁺ represents an organic cation. ]

In the following description, what has a negative charge formed by removing the organic cation (Z ⁺ ) from the salt (I) is sometimes referred to as “sulfonate anion”.

Examples of the perfluoroalkyl group of Q ¹ and Q ² include a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluoro sec-butyl group, a perfluoro tert-butyl group, and a perfluoropentyl group. And a perfluorohexyl group.
Q ¹ and Q ² are each independently preferably a fluorine atom or a trifluoromethyl group, and both Q ¹ and Q ² are more preferably a fluorine atom.

Examples of the divalent saturated hydrocarbon group for X ⁰ include a linear alkanediyl group, a branched alkanediyl group, a monocyclic or polycyclic alicyclic saturated hydrocarbon group, and among these groups, Two or more types may be combined.
Specifically, methylene group, ethylene group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1 , 7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group, dodecane-1,12-diyl group Linear alkanediyl groups such as tridecane-1,13-diyl group and tetradecane-1,14-diyl group;
Propane-1,2-diyl group, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl group Branched alkanediyl groups such as 2-methylbutane-1,4-diyl group, ethane-1,1-diyl group, propane-1,1-diyl group and propane-2,2-diyl group;
Monocyclic 2 which is a cycloalkanediyl group such as cyclobutane-1,3-diyl group, cyclopentane-1,3-diyl group, cyclohexane-1,4-diyl group, cyclooctane-1,5-diyl group Valent alicyclic saturated hydrocarbon group;
Polycyclic divalent alicyclic saturated hydrocarbon such as norbornane-1,4-diyl group, norbornane-2,5-diyl group, adamantane-1,5-diyl group, adamantane-2,6-diyl group, etc. Groups and the like.
Examples of the substituent that the divalent saturated hydrocarbon group represented by X ⁰ may have include a hydroxy group, an alkoxy group having 1 to 6 carbon atoms, and an acyloxy group having 2 to 7 carbon atoms.

Examples of the divalent saturated hydrocarbon group for A ¹⁰ , A ¹¹ and A ¹² in the formula (a-1) include the same groups as described above. Examples of the substituent that the divalent saturated hydrocarbon group may have include a hydroxy group, an alkoxy group having 1 to 6 carbon atoms, and an acyloxy group having 2 to 7 carbon atoms.
A ¹⁰ is preferably a C 3-12 divalent alicyclic saturated hydrocarbon group, more preferably an adamantanediyl group.
A ¹¹ and A ¹² are each independently preferably a linear or branched alkanediyl group having 1 to 12 carbon atoms, more preferably a linear or branched alkanediyl group having 1 to 6 carbon atoms, More preferred is a methylene group.
c is preferably 0.
X ¹⁰ and X ¹¹ are preferably each independently a carbonyloxy group or an oxycarbonyl group.

［式（ａ−２）中、Ａ¹⁴は、炭素数１〜１２の直鎖状又は分岐状アルカンジイル基を表す。＊は炭素原子との結合手を表す。］
Ａ¹⁴は、好ましくは炭素数１〜６の直鎖状又は分岐状アルカンジイル基、より好ましくはメチレン基である。 X ⁰ is preferably a linear or branched alkanediyl group having 1 to 12 carbon atoms or —A ¹³ —CO—O—A ¹⁴ — (A ¹³ is a divalent alicyclic ring having 3 to 12 carbon atoms. Represents a formula saturated hydrocarbon group, and A ¹⁴ represents a linear or branched alkanediyl group having 1 to 12 carbon atoms, and more preferably a linear or branched group having 1 to 6 carbon atoms. An alkanediyl group or a group represented by the formula (a-2).

Wherein (a-2), A ¹⁴ represents a linear or branched alkanediyl group having 1 to 12 carbon atoms. * Represents a bond with a carbon atom. ]
A ¹⁴ is preferably a linear or branched alkanediyl group having 1 to 6 carbon atoms, more preferably a methylene group.

Examples of the alkyl group for R ² include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group.
X ¹ is preferably — (CH ₂ ) _a —O—CO— ^{* 1} or — (CH ₂ ) _a —O—CH ₂ —CO—O— ^{* 1} , more preferably —CH ₂ —O—. CO- ^{* 1} or _{-CH 2 -O-CH 2 -CO-} O- * 1.

また、該脂環式炭化水素基を構成するメチレン基が、酸素原子、カルボニル基又はスルホニル基に置き換わった基としては、例えば、式（Ｙ２７）〜式（Ｙ４１）で表される基が挙げられる。

中でも、好ましくは、式（Ｙ４）、式（Ｙ８）、式（Ｙ９）又は式（Ｙ２９）で表される基であり、より好ましくは、式（Ｙ８）又は式（Ｙ２９）で表される基である。 Examples of the monovalent alicyclic hydrocarbon group having 3 to 36 carbon atoms of W ¹ include groups represented by formulas (Y1) to (Y22), respectively.

Examples of the group in which the methylene group constituting the alicyclic hydrocarbon group is replaced with an oxygen atom, a carbonyl group, or a sulfonyl group include groups represented by formulas (Y27) to (Y41). .

Among them, preferred is a group represented by the formula (Y4), formula (Y8), formula (Y9) or formula (Y29), and more preferred is a group represented by the formula (Y8) or formula (Y29). It is.

The hydrogen atom contained in the alicyclic hydrocarbon group of W ¹ is a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or a monovalent alicyclic carbonization having 3 to 12 carbon atoms. It may be substituted with a hydrogen group or a monovalent aromatic hydrocarbon group having 6 to 10 carbon atoms. As the substituent, a hydroxy group is preferable.
Examples of the alkyl 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 decyl group, and a dodecyl group.
Examples of the alkoxy group include methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, hexyloxy group, heptyloxy group, octyloxy group, decyloxy group and dodecyloxy group.
Examples of the monovalent alicyclic hydrocarbon group having 3 to 12 carbon atoms include groups represented by formula (Y1) to formula (Y13) and formula (Y20) to formula (Y22), respectively.
Examples of the aromatic hydrocarbon group having 6 to 10 carbon atoms include phenyl group, naphthyl group, p-methylphenyl group, p-tert-butylphenyl group, tolyl group, xylyl group, cumenyl group, mesityl group, 2, Examples thereof include aryl groups such as 6-diethylphenyl group and 2-methyl-6-ethylphenyl.

W ¹ is preferably an adamantyl group which may have a 2-oxoadamantyl group or an alkyl group having 1 to 12 carbon atoms or a hydroxy group.

In the formula (I), examples of W ¹ include the following groups. * Represents a bond.

Examples of the sulfonate anion of the salt (I) include the following.

Examples of the organic cation represented by Z ⁺ include organic onium cations such as organic sulfonium cation, organic iodonium cation, organic ammonium cation, benzothiazolium cation, and organic phosphonium cation. Among these, an organic sulfonium cation and an organic iodonium cation are preferable, an organic sulfonium cation is more preferable, and a cation represented by any one of the formulas (b2-1) to (b2-4) [hereinafter, depending on the formula number] Sometimes referred to as “cation (b2-1)”. ] Is more preferable.

In formula (b2-1) to formula (b2-4),
Each of R ^{b4 to} R ^b6 independently represents an aliphatic hydrocarbon group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 36 carbon atoms, or an aromatic hydrocarbon group having 6 to 36 carbon atoms; , R ^b4 and R ^b5 together form a ring containing a sulfur atom. The hydrogen atom contained in the aliphatic hydrocarbon group is a hydroxy group, an alkoxy group having 1 to 12 carbon atoms, an alicyclic saturated hydrocarbon group having 3 to 12 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms. The hydrogen atom contained in the alicyclic hydrocarbon group is substituted with a halogen atom, an alkyl group having 1 to 18 carbon atoms, an acyl group having 2 to 4 carbon atoms, or a glycidyloxy group. The hydrogen atom contained in the aromatic hydrocarbon group may be substituted with a halogen atom, a hydroxy group or an alkoxy group having 1 to 12 carbon atoms.
R ^b7 and R ^b8 each independently represent a hydroxy group, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.
m2 and n2 each independently represent an integer of 0 to 5. When m2 is 2 or more, the plurality of R ^b7 are the same or different from each other, and when n2 is 2 or more, the plurality of R ^b8 are the same or different from each other.
R ^b9 and R ^b10 each independently represent an aliphatic hydrocarbon group having 1 to 30 carbon atoms or an alicyclic hydrocarbon group having 3 to 36 carbon atoms, or R ^b9 and R ^b10 are combined together. Together with the sulfur atom to which they are attached, forms a 3- to 12-membered ring (preferably a 3- to 7-membered ring). One or more —CH ₂ — constituting the ring may be replaced by —O—, —SO— or —CO—.
R ^b11 represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 36 carbon atoms, or an aromatic hydrocarbon group having 6 to 36 carbon atoms.
R ^b12 represents an aliphatic hydrocarbon group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 36 carbon atoms, or an aromatic hydrocarbon group having 6 to 36 carbon atoms. The hydrogen atom contained in the aliphatic hydrocarbon group may be substituted with an aromatic hydrocarbon group having 6 to 18 carbon atoms, and the hydrogen atom contained in the aromatic hydrocarbon group has 1 to 12 carbon atoms. Or an alkoxycarbonyloxy group having 1 to 12 carbon atoms.
R ^b11 and R ^b12 may form a 3- to 12-membered ring (preferably a 3- to 7-membered ring) together with —CH—CO— to which they are bonded. One or more —CH ₂ — constituting the ring may be replaced by —O—, —SO— or —CO—.
R ^{b13 to} R ^b18 each independently represent a hydroxy group, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.
L ^b11 represents -S- or -O-.
o2, p2, s2, and t2 each independently represents an integer of 0 to 5.
q2 and r2 each independently represents an integer of 0 to 4.
u2 represents 0 or 1.
When o2 is 2 or more, the plurality of R ^b13 are the same or different from each other. When p2 is 2 or more, the plurality of R ^b14 are the same or different from each other. When q2 is 2 or more, the plurality of R ^b15 are the same. Alternatively, when r2 is 2 or more, a plurality of R ^b16 are the same or different from each other, when s2 is 2 or more, a plurality of R ^b17 are the same or different from each other, and when t2 is 2 or more, a plurality of R ^{b16 b18} are the same or different from each other.

R ^b4 and R ^b5 may together form a 3- to 12-membered ring (preferably a 3- to 7-membered ring) with the sulfur atom to which they are bonded.

特に、Ｒ^b4〜Ｒ^b6の脂環式炭化水素基は、好ましくは炭素数３〜１８である。Ｒ^b9〜Ｒ^b11の脂環式炭化水素基は、好ましくは炭素数４〜１２である。 Examples of the aliphatic hydrocarbon group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, octyl group and 2- Examples thereof include an alkyl group such as an ethylhexyl group. In particular, the aliphatic hydrocarbon group of R ^{b9 to} R ^b12 preferably has 1 to 18 carbon atoms, more preferably 1 to 12 carbon atoms.
Examples of the alkyl group in which a hydrogen atom is substituted with an alicyclic hydrocarbon group include a 1- (adamantan-1-yl) alkane-1-yl group.
The alicyclic hydrocarbon group may be monocyclic or polycyclic, and the hydrogen atom contained in the alicyclic hydrocarbon group may be substituted with an alkyl group. In this case, the carbon number of the alicyclic hydrocarbon group includes the carbon number of the alkyl group, and is preferably 20 or less. Examples of the monocyclic alicyclic hydrocarbon group include cycloalkyl groups such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, and a cyclodecyl group. Examples of the polycyclic alicyclic hydrocarbon group include decahydronaphthyl group, adamantyl group, norbornyl group, and the following groups.

In particular, the alicyclic hydrocarbon group of R ^{b4 to} R ^b6 preferably has 3 to 18 carbon atoms. The alicyclic hydrocarbon group represented by R ^{b9 to} R ^b11 preferably has 4 to 12 carbon atoms.

  Examples of the alicyclic hydrocarbon group in which a hydrogen atom is substituted with an alkyl group include a methylcyclohexyl group, a dimethylcyclohexyl group, a 2-alkyladamantan-2-yl group, a methylnorbornyl group, and an isobornyl group. Can be mentioned.

Examples of the aromatic hydrocarbon group include phenyl group, tolyl group, xylyl group, cumenyl group, mesityl group, 4-ethylphenyl group, 4-tert-butylphenyl group, 4-cyclohexylphenyl group, 4-adamantyl group. Substituted or unsubstituted phenyl groups such as phenyl group, 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl group; biphenylyl group, naphthyl group, phenanthryl group and the like. The aromatic hydrocarbon group also includes an aryl group in which an aromatic hydrocarbon group or an alicyclic hydrocarbon group is bonded to an aromatic ring. In this case, the number of carbon atoms is an aliphatic hydrocarbon group or an alicyclic hydrocarbon group. The number of carbons in the group can also be counted. The aromatic hydrocarbon group of R ^{b4 to} R ^b6 preferably has 6 to 224 carbon atoms.
As an aromatic hydrocarbon group by which the hydrogen atom was substituted by the alkoxy group, 4-methoxyphenyl group etc. are mentioned, for example.
Examples of the alkyl group in which a hydrogen atom is substituted with an aromatic hydrocarbon group, that is, an aralkyl group, include a benzyl group, a phenethyl group, a phenylpropyl group, a trityl group, a naphthylmethyl group, and a naphthylethyl group.
In addition, when an alkyl group or an alicyclic hydrocarbon group is contained in the aromatic hydrocarbon group, these are preferably an alkyl group having 1 to 12 carbon atoms or an alicyclic hydrocarbon group having 3 to 18 carbon atoms. .

Examples of the alkoxy group include methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, hexyloxy group, heptyloxy group, octyloxy group, decyloxy group and dodecyloxy group.
Examples of the acyl group include an acetyl group, a propionyl group, and a butyryl group.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
Examples of the alkylcarbonyloxy group include methylcarbonyloxy group, ethylcarbonyloxy group, n-propylcarbonyloxy group, isopropylcarbonyloxy group, n-butylcarbonyloxy group, sec-butylcarbonyloxy group, tert-butylcarbonyloxy group. Group, pentylcarbonyloxy group, hexylcarbonyloxy group, octylcarbonyloxy group, 2-ethylhexylcarbonyloxy group and the like.

The ring containing a sulfur atom which may be formed by combining R ^b4 and R ^b5 is any of monocyclic, polycyclic, aromatic, non-aromatic, saturated and unsaturated rings. If it contains one or more sulfur atoms, it may further contain one or more sulfur atoms and / or one or more oxygen atoms. As the ring, a ring having 3 to 18 carbon atoms is preferable, and a ring having 4 to 18 carbon atoms is more preferable.

Examples of the ring formed together with the sulfur atom to which R ^b9 and R ^b10 are bonded include, for example, a thiolane-1-ium ring (tetrahydrothiophenium ring), a thian-1-ium ring, and a 1,4-oxathian-4-ium. A ring etc. are mentioned.
Examples of the ring formed with —CH—CO— in which R ^b11 and R ^b12 are bonded include an oxocycloheptane ring, an oxocyclohexane ring, an oxonorbornane ring, and an oxoadamantane ring.

Examples of the cation (b2-1) include the following cations.

Examples of the cation (b2-2) include the following cations.

Examples of the cation (b2-3) include the following cations.

Among the cation (b2-1) to cation (b2-4), the cation (b2-1) is preferable, more preferably a cation represented by the formula (b2-1-1) (hereinafter referred to as “cation ( more preferably triphenylsulfonium cation (in formula (b2-1-1), v2 = w2 = x2 = 0), diphenyltolylsulfonium cation (formula ( b2-1-1), v2 = w2 = 0, x2 = 1, R ^b21 is a methyl group) or a tolylsulfonium cation (in formula (b2-1-1), v2 = w2 = x2 = 1 and R ^b19 , R ^b20 and R ^b21 are all methyl groups).

式（ｂ２−１−１）中、
Ｒ^b19、Ｒ^b20及びＲ^b21は、それぞれ独立に、ハロゲン原子（より好ましくはフッ素原子）、ヒドロキシ基、炭素数１〜１２のアルキル基、炭素数１〜１２のアルコキシ基又は炭素数３〜１８の脂環式炭化水素基を表す。また、Ｒ^b19〜Ｒ^b21から選ばれる２つが一緒になって硫黄原子を含む環を形成してもよい。
ｖ２、ｗ２及びｘ２は、それぞれ独立に０〜５の整数（好ましくは０又は１）を表す。
ｖ２が２以上のとき、複数のＲ^b19は互いに同一又は相異なり、ｗ２が２以上のとき、複数のＲ^b20は互いに同一又は相異なり、ｘ２が２以上のとき、複数のＲ^b21は互いに同一又は相異なる。

In formula (b2-1-1),
R ^b19 , R ^b20 and R ^b21 each independently represent a halogen atom (more preferably a fluorine atom), a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or 3 to 18 carbon atoms. Represents an alicyclic hydrocarbon group. It is also possible that two selected from R ^b19 to R ^b21 together form a ring containing a sulfur atom.
v2, w2 and x2 each independently represent an integer of 0 to 5 (preferably 0 or 1).
When v2 is 2 or more, the plurality of R ^b19 are the same or different from each other. When w2 is 2 or more, the plurality of R ^b20 are the same or different from each other. When x2 is 2 or more, the plurality of R ^b21 are the same. Or different.

Among them, R ^b19 , R ^b20 and R ^b21 are preferably each independently a halogen atom (more preferably a fluorine atom), a hydroxy group, an alkyl group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms. It is.

  Specific examples of the cation represented by the formula (b2-1-1) include cations described in JP 2010-204646 A.

The salt (I) is a combination of a sulfonate anion and an organic cation, and these can be arbitrarily combined.
Specific examples of this combination include those listed in Tables 1 to 4.

Among the salts (I) shown in Tables 1 to 4, more preferable salts (I) are as follows.

この反応の溶媒としてはクロロホルム、及びアセトニトリル等が挙げられる。 The salt (I) (hereinafter sometimes referred to as “salt (I1)”) in the case where L ¹ is —CF ₂ —, X ⁰ is a methylene group, and X ¹ is —CH ₂ —O—CO— ^{* 1} . For example, it can be produced by reacting a salt represented by the formula (I1-a) with a compound represented by the formula (Ib) in a solvent. In the following description, each symbol has the same meaning as described above unless otherwise specified.

Examples of the solvent for this reaction include chloroform and acetonitrile.

この反応の塩基触媒としては、Ｎ−メチルピロリジン、トリエチルアミン等が挙げられる。
この反応の溶媒としてはクロロホルム等が挙げられる。
式（Ｉ１−ｄ）で表される化合物としては、下記式で表される化合物等が挙げられる。

また、式（Ｉ１−ｄ）で表される化合物の代わりに、Ｗ^１−ＣＯ−ＯＨを用いてもよい。Ｗ^１−ＣＯ−ＯＨとしては、下記式で表される化合物等が挙げられる。

The salt represented by the formula (I1-a) includes, for example, a salt represented by the formula (I1-c) and a compound represented by the formula (I1-d) in a solvent in the presence of a base catalyst. It can be produced by reacting.

Examples of the base catalyst for this reaction include N-methylpyrrolidine and triethylamine.
Examples of the solvent for this reaction include chloroform.
Examples of the compound represented by the formula (I1-d) include a compound represented by the following formula.

In addition, W ¹ —CO—OH may be used instead of the compound represented by the formula (I1-d). Examples of W ¹ —CO—OH include compounds represented by the following formulas.

The salt represented by the formula (I1-c) can be obtained by oxidizing the salt represented by the formula (I1-e) in a solvent.
Examples of the solvent here include chloroform.
Examples of the oxidizing agent herein include a mixture of an N-oxide aqueous solution and an osmium tetroxide aqueous solution.

The salt represented by the formula (I1-e) can be synthesized, for example, by the method described in JP-A-2008-260745, and examples thereof include the salts represented below.

この反応の溶媒としてはクロロホルム、及びアセトニトリル等が挙げられる。 A salt (I) (hereinafter sometimes referred to as “salt (I2)”) in which L ¹ is a carbonyl group, X ⁰ is a single bond, and X ¹ is —CH ₂ —O—CO— ^{* 1} . For example, it can be produced by reacting a salt represented by the formula (I2-a) with a compound represented by the formula (Ib) in a solvent.

Examples of the solvent for this reaction include chloroform and acetonitrile.

この反応の触媒としては、酸化銀又は過塩素酸銀等が挙げられる。
この反応の溶媒としてはクロロホルム、ジクロロメタン、ジクロロエタン、メタノール、ジメチルホルムアミド及びアセトニトリル等が挙げられる。
式（Ｉ−ｄ）で表される化合物としては、下記式で表される化合物等が挙げられる。

The salt represented by the formula (I2-a) is obtained by, for example, reacting the salt represented by the formula (I2-c) and the compound represented by the formula (Id) in a solvent in the presence of a catalyst. Can be manufactured. This reaction is shown in the form of a reaction formula as follows.

Examples of the catalyst for this reaction include silver oxide and silver perchlorate.
Examples of the solvent for this reaction include chloroform, dichloromethane, dichloroethane, methanol, dimethylformamide, and acetonitrile.
Examples of the compound represented by the formula (Id) include compounds represented by the following formula.

The salt represented by the formula (I2-c) is obtained by reacting the compound represented by the formula (Ie) and the salt represented by the formula (If) in a solvent to form the formula (I2-g). ) And then treating with an acid.
Examples of the solvent here include chloroform.
An oxalic acid etc. are mentioned as an acid here.

The salt represented by the formula (If) can be obtained by reacting the salt represented by the formula (Ih) with the compound represented by the formula (Ib).
The salt represented by the formula (Ih) can be synthesized, for example, by the method described in JP 2008-127367 A.

この反応の溶媒としてはクロロホルム、及びアセトニトリル等が挙げられる。 A salt in which L ¹ is a methylene group, X ⁰ is —Ad—CO—O—CH ₂ — (Ad represents an adamantanediyl group), and X ¹ is —CH ₂ —O—CO— ^{* 1.} (I) (hereinafter sometimes referred to as “salt (I3)”) is, for example, a salt represented by the formula (I3-a) and a compound represented by the formula (Ib) in a solvent. It can be produced by reacting.

Examples of the solvent for this reaction include chloroform and acetonitrile.

この反応の触媒としては、酸化銀又は過塩素酸銀等が挙げられる。
この反応の溶媒としてはクロロホルム、ジクロロメタン、ジクロロエタン、メタノール、ジメチルホルムアミド及びアセトニトリル等が挙げられる。
式（Ｉ−ｄ）で表される化合物としては、上記と同じ化合物等が挙げられる。 The salt represented by the formula (I3-a) is obtained by, for example, reacting a salt represented by the formula (I3-c) with a compound represented by the formula (Id) in a solvent in the presence of a catalyst. Can be manufactured. This reaction is shown in the form of a reaction formula as follows.

Examples of the catalyst for this reaction include silver oxide and silver perchlorate.
Examples of the solvent for this reaction include chloroform, dichloromethane, dichloroethane, methanol, dimethylformamide, and acetonitrile.
Examples of the compound represented by the formula (Id) include the same compounds as described above.

ここでの溶媒としては、クロロホルム等が挙げられる。
ここでの酸としては、シュウ酸等が挙げられる。 The salt represented by the formula (I3-c) is obtained by reacting the obtained compound represented by the formula (I3-e) with the salt represented by the formula (If) in a solvent. After obtaining the salt represented by I3-g), it can be obtained by treating with an acid.

Examples of the solvent here include chloroform.
An oxalic acid etc. are mentioned as an acid here.

ここでの還元剤としては、水素化ホウ素ナトリウム等が挙げられる。
ここでの溶媒としては、アセトニトリル等が挙げられる。 The compound represented by the formula (I3-e) can be obtained by reacting the compound represented by the formula (I3-h) in a solvent in the presence of a reducing agent.

Examples of the reducing agent here include sodium borohydride.
Examples of the solvent here include acetonitrile.

まず、式（Ｉ３−ｉ）で表される化合物と式（Ｉ−ｂ）で表される化合物とを溶媒中で反応させることにより、式（Ｉ３−ｋ）で表される化合物を得る。溶媒としては、クロロホルム等が挙げられる。
得られた式（Ｉ３−ｋ）で表される化合物と式（Ｉ−ｅ）で表される化合物とを、溶媒中で反応させることにより、式（Ｉ３−ｈ）で表される化合物を得ることができる。
ここでの溶媒としては、クロロホルム等が挙げられる。 The compound represented by the formula (I3-h) can be produced, for example, by the method shown below.

First, a compound represented by formula (I3-k) is obtained by reacting a compound represented by formula (I3-i) with a compound represented by formula (Ib) in a solvent. Examples of the solvent include chloroform.
The compound represented by the formula (I3-h) is obtained by reacting the compound represented by the formula (I3-k) and the compound represented by the formula (Ie) in a solvent. be able to.
Examples of the solvent here include chloroform.

  The salt represented by the formula (I3-f) here can also be obtained by the same method as described above.

この反応の溶媒としてはクロロホルム、及びアセトニトリル等が挙げられる。 L ¹ is a methylene group, X ⁰ is —Ad—CO—O—CH ₂ — (Ad represents an adamantanediyl group), and X ¹ is —CH ₂ —O—CH ₂ —CO—O— ^{* 1.} The salt (I) (hereinafter sometimes referred to as “salt (I4)”) is, for example, a salt represented by the formula (I4-a) and a compound represented by the formula (Ib) Can be made to react in a solvent.

Examples of the solvent for this reaction include chloroform and acetonitrile.

この反応の塩基触媒としては、ピリジン、Ｎ−メチルピロリジン、トリエチルアミン等が挙げられる。
この反応の溶媒としてはクロロホルム等が挙げられる。
式（Ｉ４−ｄ）で表される化合物としては、下記式で表される化合物等が挙げられる。

The salt represented by the formula (I4-a) is obtained by reacting the salt represented by the formula (I3-c) with the compound represented by the formula (I4-d) in the presence of a base catalyst in a solvent. Can be manufactured.

Examples of the base catalyst for this reaction include pyridine, N-methylpyrrolidine, triethylamine and the like.
Examples of the solvent for this reaction include chloroform.
Examples of the compound represented by the formula (I4-d) include a compound represented by the following formula.

<Acid generator>
The acid generator of the present invention contains salt (I) which is a salt of the present invention. The acid generator of the present invention preferably further contains an acid generator other than the salt (I) (hereinafter sometimes referred to as “acid generator (B)”).

  As the acid generator (B), a known acid generator can be used, and an ionic acid generator or a nonionic generator may be used, but an ionic acid generator is preferable. Examples of the ionic acid generator include an ionic acid generator comprising a combination of a sulfonic acid anion other than that constituting the salt (I) and an organic cation constituting the salt (I), a known cation and a known anion. And an ionic acid generator comprising a combination of

As an acid generator (B), the salt represented by either of Formula (B1-1)-Formula (B1-24) is mentioned, for example.

Of these, those containing an arylsulfonium cation are preferred. Examples of such a salt include formula (B1-1), formula (B1-2), formula (B1-3), formula (B1-6), formula (B1-7), and formula (B1-11). , Formula (B1-12), formula (B1-13), formula (B1-14), formula (B1-21), formula (B1-22), formula (B1-23) and formula (B1-24) Examples thereof include salts represented by any of them.
Further, those containing an anion having an acid labile group are more preferable. Examples of such a salt include a salt represented by any one of formulas (B1-21) to (B1-24). Here, examples of the acid labile group include a group represented by the following formula (1) and a group represented by the formula (2).

  The acid generator of the present invention may be the salt (I) alone, but preferably comprises the salt (I) and the acid generator (B). When the acid generator of the present invention is an acid generator composed of the salt (I) and the acid generator (B), the content of the salt (I) is based on the total amount of the acid generator of the present invention. Preferably they are 1 mass% or more and 50 mass% or less, More preferably, they are 2 mass% or more and 40 mass% or less, More preferably, they are 3 mass% or more and 30 mass% or less.

<Resist composition>
The resist composition of the present invention contains the acid generator of the present invention and a resin having an acid labile group (hereinafter sometimes referred to as “resin (A)”).
The resist composition of the present invention preferably further contains a solvent (D).
The resist composition of the present invention preferably further contains a basic compound (C).

  The content of the acid generator of the present invention is preferably 1 part by mass or more (more preferably 3 parts by mass or more), preferably 30 parts by mass or less (more preferably 25 parts by mass) with respect to 100 parts by mass of the resin (A). Part or less).

<Resin (A)>
The resin (A) is usually a resin containing a structural unit having an acid labile group (hereinafter sometimes referred to as “structural unit (a1)”). The structural unit (a1) is derived from a monomer having an acid labile group (hereinafter sometimes referred to as “monomer (a1)”).

［式（１）中、Ｒ^a1〜Ｒ^a3は、それぞれ独立に、炭素数１〜８のアルキル基、炭素数３〜２０の脂環式炭化水素基又はこれらを組合わせた基を表すか、Ｒ^a1及びＲ^a2は互いに結合して炭素数２〜２０の２価の炭化水素基を形成する。＊は結合手を表す。］

［式（２）中、Ｒ^a1'及びＲ^a2'は、それぞれ独立に、水素原子又は炭素数１〜１２の炭化水素基を表し、Ｒ^a3'は、炭素数１〜２０の炭化水素基を表すか、Ｒ^a2'及びＲ^a3'は互いに結合して炭素数２〜２０の２価の炭化水素基を形成し、該炭化水素基及び該２価の炭化水素基に含まれる−ＣＨ_２−は、−Ｏ−又は−Ｓ−で置き換わってもよい。］ <Acid labile group>
The “acid labile group” means a group having a leaving group and forming a hydrophilic group (for example, a hydroxy group or a carboxy group) by leaving the leaving group by contact with an acid. Examples of the acid labile group include a group represented by the formula (1) and a group represented by the formula (2).

[In Formula (1), R ^<a1 > -R < ^a3 > respectively independently represents a C1-C8 alkyl group, a C3-C20 alicyclic hydrocarbon group, or the group which combined these, R ^a1 and R ^a2 are bonded to each other to form a divalent hydrocarbon group having 2 to 20 carbon atoms. * Represents a bond. ]

[In Formula (2), R ^{a1 ′} and R ^{a2 ′} each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, and R ^{a3 ′} represents a hydrocarbon group having 1 to 20 carbon atoms. R ^{a2 ′} and R ^{a3 ′} are bonded to each other to form a divalent hydrocarbon group having 2 to 20 carbon atoms, and —CH ₂ — contained in the hydrocarbon group and the divalent hydrocarbon group. May be replaced by -O- or -S-. ]

アルキル基と脂環式炭化水素基とを組合わせた基としては、例えば、メチルシクロヘキシル基、ジメチルシクロへキシル基、メチルノルボルニル基等が挙げられる。 ^Examples of the alkyl group represented by R ^{a1 to} R ^a3 include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, and an octyl group.
The alicyclic hydrocarbon group for R ^{a1 to} R ^a3 may be monocyclic or polycyclic. Examples of the monocyclic alicyclic hydrocarbon group include cycloalkyl groups such as a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. Examples of the polycyclic alicyclic hydrocarbon group include a decahydronaphthyl group, an adamantyl group, a norbornyl group, and the following groups (* represents a bond). The alicyclic hydrocarbon group of R ^{a1 to} R ^a3 preferably has 3 to 16 carbon atoms.

Examples of the group obtained by combining an alkyl group and an alicyclic hydrocarbon group include a methylcyclohexyl group, a dimethylcyclohexyl group, and a methylnorbornyl group.

Examples of —C (R ^a1 ) (R ^a2 ) (R ^a3 ) in the case where R ^a1 and R ^a2 are bonded to each other to form a divalent hydrocarbon group include the following groups. The divalent hydrocarbon group preferably has 3 to 12 carbon atoms. In each formula, R ^a3 has the same meaning as described above, and * represents a bond to —O—.

Examples of the group represented by the formula (1) include a 1,1-dialkylalkoxycarbonyl group (in the formula (1), R ^{a1 to} R ^a3 are alkyl groups, preferably a tert-butoxycarbonyl group), 2-alkyladamantan-2-yloxycarbonyl group (in the formula (1), R ^a1 , R ^a2 and a carbon atom form an adamantyl group, and R ^a3 is an alkyl group) and 1- (adamantane-1- Yl) -1-alkylalkoxycarbonyl group (in the formula (1), R ^a1 and R ^a2 are alkyl groups, and R ^a3 is an adamantyl group).

Examples of the hydrocarbon group of R ^{a1 ′ to} R ^{a3 ′} include an alkyl group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and a group obtained by combining these.
Examples of the alkyl group and alicyclic hydrocarbon group are the same as those described above.
Aromatic hydrocarbon groups include phenyl, naphthyl, anthryl, p-methylphenyl, p-tert-butylphenyl, p-adamantylphenyl, tolyl, xylyl, cumenyl, mesityl, biphenyl Groups, phenanthryl groups, 2,6-diethylphenyl groups, aryl groups such as 2-methyl-6-ethylphenyl, and the like.
Examples of the divalent hydrocarbon group formed by combining R ^{a2 ′} and R ^{a3 ′} include groups in which one hydrogen atom has been removed from the hydrocarbon groups of R ^{a1 ′ to} R ^{a3 ′} .

In Formula (2), it is preferable that at least one of R ^{a1 ′} and R ^{a2 ′} is a hydrogen atom.
Specific examples of the group represented by the formula (2) include the following groups. * Represents a bond.

  The monomer (a1) is preferably a monomer having an acid labile group and an ethylenically unsaturated bond, more preferably a (meth) acrylic monomer having an acid labile group.

  Among the (meth) acrylic monomers having an acid labile group, those having an alicyclic hydrocarbon group having 5 to 20 carbon atoms are preferable. If the resin (A) having a structural unit derived from the monomer (a1) having a bulky structure such as an alicyclic hydrocarbon group is used in the resist composition, the resolution of the resist pattern can be improved.

As a structural unit derived from a (meth) acrylic monomer having a group represented by formula (1), preferably a structural unit represented by formula (a1-1) or a structure represented by formula (a1-2) Units are listed. These may be used alone or in combination of two or more. In this specification, the structural unit represented by the formula (a1-1) and the structural unit represented by the formula (a1-2) are represented by the structural unit (a1-1) and the structural unit (a1-2), respectively. The monomer that derives the structural unit (a1-1) and the monomer that derives the structural unit (a1-2) may be referred to as a monomer (a1-1) and a monomer (a1-2), respectively.
Especially, it is preferable that resin has a structural unit (a1-1).

［式（ａ１−１）及び式（ａ１−２）中、
Ｌ^a1及びＬ^a2は、それぞれ独立に、−Ｏ−又は^＊−Ｏ−（ＣＨ₂）_k1−ＣＯ−Ｏ−を表し、ｋ１は１〜７の整数を表し、＊は−ＣＯ−との結合手を表す。
Ｒ^a4及びＲ^a5は、それぞれ独立に、水素原子又はメチル基を表す。
Ｒ^a6及びＲ^a7は、それぞれ独立に、炭素数１〜８のアルキル基、炭素数３〜１８の脂環式炭化水素基又はこれらを組合わせた基を表す。
ｍ１は０〜１４の整数を表す。
ｎ１は０〜１０の整数を表す。
ｎ１’は０〜３の整数を表す。］

[In Formula (a1-1) and Formula (a1-2),
L ^a1 and L ^a2 each independently represent —O— or ^* —O— (CH ₂ ) _k1 —CO—O—, k1 represents an integer of 1 to 7, and * represents a bond to —CO—. Represents a hand.
R ^a4 and R ^a5 each independently represent a hydrogen atom or a methyl group.
R ^a6 and R ^a7 each independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a group obtained by combining these.
m1 represents the integer of 0-14.
n1 represents an integer of 0 to 10.
n1 ′ represents an integer of 0 to 3. ]

L ^a1 and L ^a2 are preferably —O— or ^* —O— (CH ₂ ) _k1 —CO—O—, more preferably —O—. k1 is preferably an integer of 1 to 4, more preferably 1.
R ^a4 and R ^a5 are preferably methyl groups.
Examples of the alkyl group of R ^a6 and R ^a7 , the alicyclic hydrocarbon group, and the group obtained by combining these include the same groups as those described for R ^{a1 to} R ^a3 in formula (1).
The alkyl group for R ^a6 and R ^a7 preferably has 6 or less carbon atoms.
The alicyclic hydrocarbon group of R ^a6 and R ^a7 preferably has 8 or less carbon atoms, more preferably 6 or less.
m1 is preferably an integer of 0 to 3, more preferably 0 or 1.
n1 is preferably an integer of 0 to 3, more preferably 0 or 1.
n1 ′ is preferably 0 or 1.

As a monomer (a1-1), the monomer described in Unexamined-Japanese-Patent No. 2010-204646 is mentioned, for example. Among these, a monomer represented by any one of formula (a1-1-1) to formula (a1-1-8) is preferable, and any one of formula (a1-1-1) to formula (a1-1-4) is preferable. The monomer represented by is more preferable.

Examples of the monomer (a1-2) include 1-ethylcyclopentan-1-yl (meth) acrylate, 1-ethylcyclohexane-1-yl (meth) acrylate, and 1-ethylcycloheptan-1-yl (meth). Examples include acrylate, 1-methylcyclopentan-1-yl (meth) acrylate, and 1-isopropylcyclopentan-1-yl (meth) acrylate. A monomer represented by any one of formula (a1-2-1) to formula (a1-2-12) is preferred, and formula (a1-2-3) to formula (a1-2-4) or formula (a1- The monomer represented by any one of 2-9) to formula (a1-2-10) is more preferred, and the monomer represented by formula (a1-2-3) or formula (a1-2-9) is more preferred. .

  When the resin (A) contains the structural unit (a1-1) and / or the structural unit (a1-2), the total content thereof is usually 10 to 95 mol with respect to all the structural units of the resin (A). %, Preferably 15 to 90 mol%, more preferably 20 to 85 mol%.

式（ａ１−３）中、
Ｒ^a9は、ヒドロキシ基を有していてもよい炭素数１〜３の脂肪族炭化水素基、カルボキシ基、シアノ基、水素原子又は−ＣＯＯＲ^a13を表す。
Ｒ^a13は、炭素数１〜８の脂肪族炭化水素基、炭素数３〜２０の脂環式炭化水素基、又はこれらを組み合わせた基を表し、該脂肪族炭化水素基及び該脂環式炭化水素基に含まれる水素原子は、ヒドロキシ基で置換されていてもよく、該脂肪族炭化水素基及び該脂環式炭化水素基に含まれるメチレン基は、酸素原子又はカルボニル基で置き換わっていてもよい。
Ｒ^a10、Ｒ^a11及びＲ^a12は、それぞれ独立に、炭素数１〜８のアルキル基、炭素数３〜２０の脂環式炭化水素基又はこれらを組合わせた基を表すか、Ｒ^a10及びＲ^a11は互いに結合して炭素数２〜２０の２価の炭化水素基を形成する。 Examples of the structural unit (a1) having a group represented by the formula (1) also include a structural unit represented by the formula (a1-3). In this specification, the structural unit represented by the formula (a1-3) may be referred to as the structural unit (a1-3) and the monomer that derives the structural unit (a1-3) may be referred to as a monomer (a1-3). is there.

In formula (a1-3),
R ^a9 represents an aliphatic hydrocarbon group having 1 to 3 carbon atoms which may have a hydroxy group, a carboxy group, a cyano group, a hydrogen atom, or —COOR ^a13 .
R ^a13 represents an aliphatic hydrocarbon group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or a combination thereof, and the aliphatic hydrocarbon group and the alicyclic carbon group. The hydrogen atom contained in the hydrogen group may be substituted with a hydroxy group, and the methylene group contained in the aliphatic hydrocarbon group and the alicyclic hydrocarbon group may be replaced with an oxygen atom or a carbonyl group. Good.
R ^a10, R ^a11 and R ^a12 are each independently an alkyl group having 1 to 8 carbon atoms, or an alicyclic hydrocarbon group or a group obtained by combining these C3-20, R ^a10 and R ^a11 are bonded to each other to form a divalent hydrocarbon group having 2 to 20 carbon atoms.

Here, examples of —COOR ^a13 in R ^a9 include a group in which a carbonyl group is bonded to an alkoxy group such as a methoxycarbonyl group and an ethoxycarbonyl group.

Examples of the aliphatic hydrocarbon group which may have a hydroxy group for R ^a9 include a methyl group, an ethyl group, a propyl group, a hydroxymethyl group and a 2-hydroxyethyl group.
^Examples of the group ^{consisting of} an aliphatic hydrocarbon group represented by R ^a13 , an alicyclic hydrocarbon group, and an aliphatic hydrocarbon group having 1 to 8 carbon atoms and an alicyclic hydrocarbon group having 3 to 20 carbon atoms include, for example, methyl Group, ethyl group, propyl group, cyclopentyl group, cyclopropyl group, adamantyl group, adamantylmethyl group, 1-adamantyl-1-methylethyl group, 2-oxo-oxolan-3-yl group and 2-oxo-oxolane-4 -An yl group etc. are mentioned.
^{Examples of} R ^{a10 to} R ^a12 include the same groups as R ^{a1 to} R ^a3 in formula (1).
As —C (R ^a10 ) (R ^a11 ) (R ^a12 ) when R ^a10 and R ^a11 are bonded to each other to form a divalent hydrocarbon group, the following groups are preferred.

  Specific examples of the monomer (a1-3) include 5-norbornene-2-carboxylic acid-tert-butyl, 5-norbornene-2-carboxylic acid 1-cyclohexyl-1-methylethyl, and 5-norbornene-2-carboxylic acid. Acid 1-methylcyclohexyl, 5-norbornene-2-carboxylic acid 2-methyl-2-adamantyl, 5-norbornene-2-carboxylic acid 2-ethyl-2-adamantyl, 5-norbornene-2-carboxylic acid 1- (4 -Methylcyclohexyl) -1-methylethyl, 5-norbornene-2-carboxylic acid 1- (4-hydroxycyclohexyl) -1-methylethyl, 5-norbornene-2-carboxylic acid 1-methyl-1- (4-oxo (Cyclohexyl) ethyl and 1- (1-adamantyl) -1-methyl 5-norbornene-2-carboxylate Chill, and the like.

  Since the resin (A) containing the structural unit (a1-3) includes a sterically bulky structural unit, the resist composition of the present invention containing such a resin (A) is more expensive. A resist pattern can be obtained with resolution. Further, since a rigid norbornane ring is introduced into the main chain, the resulting resist pattern tends to be excellent in dry etching resistance.

  When the resin (A) includes the structural unit (a1-3), the content is preferably 10 to 95 mol%, more preferably 15 to 90 mol%, based on all the structural units of the resin (A). 20-85 mol% is more preferable.

［式（ａ１−４）中、
Ｒ^a32は、水素原子、ハロゲン原子、又は、ハロゲン原子を有してもよい炭素数１〜６のアルキル基を表す。
Ｒ^a33は、ハロゲン原子、ヒドロキシ基、炭素数１〜６のアルキル基、炭素数１〜６のアルコキシ基、炭素数２〜４のアシル基、炭素数２〜４のアシルオキシ基、アクリロイルオキシ基又はメタクリロイルオキシ基を表す。
ｌａは０〜４の整数を表す。ｌａが２以上である場合、複数のＲ^a33は互いに同一であっても異なってもよい。
Ｒ^a34、Ｒ^a35及びＲ^a36はそれぞれ独立に、水素原子又は炭素数１〜１２の炭化水素基を表し、Ｒ^a34は、炭素数１〜２０の炭化水素基を表すか、Ｒ^a35及びＲ^a36は互いに結合して炭素数２〜２０の２価の炭化水素基を形成し、該炭化水素基及び該２価の炭化水素基に含まれる−ＣＨ_２−は、−Ｏ−又は−Ｓ−で置き換わってもよい。］ As the structural unit (a1) having a group represented by the formula (2), a structural unit represented by the formula (a1-4) (hereinafter sometimes referred to as “structural unit (a1-4)”). Can be mentioned.

[In the formula (a1-4),
R ^a32 represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom.
R ^a33 is a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an acyl group having 2 to 4 carbon atoms, an acyloxy group having 2 to 4 carbon atoms, an acryloyloxy group, or Represents a methacryloyloxy group.
la represents an integer of 0 to 4. When la is 2 or more, the plurality of R ^a33 may be the same as or different from each other.
R ^a34, R ^a35 and R ^a36 each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, R ^a34 may represent a hydrocarbon group having 1 to 20 carbon atoms, R ^a35 and R ^a36 Are bonded to each other to form a divalent hydrocarbon group having 2 to 20 carbon atoms, and —CH ₂ — contained in the hydrocarbon group and the divalent hydrocarbon group is —O— or —S—. It may be replaced. ]

^Examples of the alkyl group for R ^a32 and R ^a33 include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a pentyl group, and a hexyl group. The alkyl group is preferably an alkyl group having 1 to 4 carbon atoms, more preferably a methyl group or an ethyl group, and further preferably a methyl group.
Examples of the halogen atom for R ^a32 and R ^a33 include a fluorine atom, a chlorine atom and a bromine atom.

In formula (a1-4), R ^a32 is preferably a hydrogen atom.
R ^a33 is preferably an alkoxy group having 1 to 4 carbon atoms, more preferably a methoxy group or an ethoxy group, and further preferably a methoxy group.
la is preferably 0 or 1, more preferably 0.
R ^a34 is preferably a hydrogen atom.
R ^a35 is preferably a hydrocarbon group having 1 to 12 carbon atoms, more preferably a methyl group or an ethyl group.
The hydrocarbon group for ^Ra36 is preferably an alkyl group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a combination thereof. More preferably, they are a C1-C18 alkyl group, a C3-C18 alicyclic aliphatic hydrocarbon group, or a C7-C18 aralkyl group. The alkyl group and the alicyclic hydrocarbon group are preferably unsubstituted. When the aromatic hydrocarbon group has a substituent, the substituent is preferably an aryloxy group having 6 to 10 carbon atoms.

Examples of the monomer for deriving the structural unit monomer (a1-4) include monomers described in JP2010-204646A. Among these, monomers represented by formula (a1-4-1) to formula (a1-4-7) are preferable, and monomers represented by formula (a1-4-1) to formula (a1-4-5) are preferable. Is more preferable.

  When resin (A) has a structural unit (a1-4), the content rate is preferable with respect to all the structural units of resin (A), and 10-95 mol% is preferable, and 15-90 mol% is more preferable. 20 to 85 mol% is more preferable.

式（ａ１−５）中、
Ｒ^３１は、ハロゲン原子を有してもよい炭素数１〜６のアルキル基、水素原子又はハロゲン原子を表す。
Ｚ^ａ１は、単結合又は＊−［ＣＨ₂］_k1−ＣＯ−Ｌ^ａ４−を表す。ここで、ｋ１は１〜４の整数を表す。＊は、Ｌ^ａ１との結合手を表す。
Ｌ^ａ１、Ｌ^ａ２、Ｌ^ａ３及びＬ^ａ４は、それぞれ独立に、−Ｏ−又は−Ｓ−を表す。
ｓ１は、１〜３の整数を表す。
ｓ１’は、０〜３の整数を表す。 Examples of the structural unit (a1) include a structural unit represented by the formula (a1-5) (hereinafter may be referred to as “structural unit (a1-5)”).

In formula (a1-5),
R ³¹ represents a C 1-6 alkyl group which may have a halogen atom, a hydrogen atom or a halogen atom.
Z ^a1 represents a single bond or * — [CH ₂ ] _k1 —CO—L ^a4 —. Here, k1 represents an integer of 1 to 4. * Represents a bond with L ^a1 .
L ^a1 , L ^a2 , L ^a3 and L ^a4 each independently represent —O— or —S—.
s1 represents an integer of 1 to 3.
s1 ′ represents an integer of 0 to 3.

In formula (a1-5), R ³¹ is preferably a hydrogen atom, a methyl group or a trifluoromethyl group.
L ^a1 is preferably —O—.
One of L ^a2 and L ^a3 is preferably —O— and the other is —S—.
s1 is preferably 1.
s1 ′ is preferably an integer of 0 to 2.
Z ^a1 is preferably a single bond or * —CH ₂ —CO—O—.

As a monomer (a1-5), the following monomers are mentioned, for example.

  When resin (A) has a structural unit (a1-5), the content rate is preferable 1-50 mol% with respect to all the structural units of resin (A), and 3-45 mol% is more preferable. 5 to 40 mol% is more preferable.

<Structural unit without acid labile group>
The resin (A) may have a structural unit having no acid labile group (hereinafter sometimes referred to as “structural unit (s)”). The structural unit (s) is derived from a monomer having no acid labile group (hereinafter sometimes referred to as “monomer (s)”).
The monomer (s) is preferably a monomer having a hydroxy group or a lactone ring. An acid stable monomer (hereinafter sometimes referred to as “monomer (a3)”) containing a structural unit and / or a lactone ring derived from an acid stable monomer having a hydroxy group (hereinafter sometimes referred to as “monomer (a2)”) If a resin having a derived structural unit is used for preparing a resist composition, the resolution of the resist pattern and the adhesion to the substrate can be improved.

<Structural unit (a2)>
The hydroxy group contained in the structural unit (a2) may be an alcoholic hydroxy group or a phenolic hydroxy group.
A structure having a phenolic hydroxy group as the structural unit (a2) when the resist composition of the present invention is applied to KrF excimer laser exposure (248 nm), exposure to high energy rays such as an electron beam or EUV (extreme ultraviolet light) It is preferable to use the unit (a2). When applied to ArF excimer laser exposure (193 nm) or the like, the structural unit (a2) is preferably a structural unit (a2) having an alcoholic hydroxy group, and more preferably a structural unit (a2-1). As the structural unit (a2), one type may be contained alone, or two or more types may be used in combination.

［式（ａ２−０）中、
Ｒ^a30は、水素原子、ハロゲン原子又はハロゲン原子を有してもよい炭素数１〜６のアルキル基を表す。
Ｒ^a31は、ハロゲン原子、ヒドロキシ基、炭素数１〜６のアルキル基、炭素数１〜６のアルコキシ基、炭素数２〜４のアシル基、炭素数２〜４のアシルオキシ基、アクリロイルオキシ基又はメタクリロイルオキシ基を表す。
ｍａは０〜４の整数を表す。ｍａが２以上の整数である場合、複数のＲ^a31は互いに同一であっても異なってもよい。］ Examples of the structural unit (a2) having a phenolic hydroxy group include a structural unit represented by the formula (a2-0) (hereinafter sometimes referred to as “structural unit (a2-0)”).

[In the formula (a2-0),
R ^a30 represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom.
R ^a31 is a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an acyl group having 2 to 4 carbon atoms, an acyloxy group having 2 to 4 carbon atoms, an acryloyloxy group, or Represents a methacryloyloxy group.
ma represents an integer of 0 to 4. When ma is an integer of 2 or more, the plurality of R ^a31 may be the same as or different from each other. ]

^Examples of the alkyl group having 1 to 6 carbon atoms which may have a halogen atom of R ^{a30 include} the same groups as R ^{31 in} formula (a1-5). Among them, R ^a30 is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom, a methyl group or an ethyl group, and even more preferably a hydrogen atom or a methyl group.
The alkoxy group of R ^a31 is preferably an alkoxy group having 1 to 4 carbon atoms, more preferably a methoxy group or an ethoxy group, and further preferably a methoxy group.
ma is preferably 0, 1 or 2, more preferably 0 or 1, and particularly preferably 0.

Examples of the monomer that derives the structural unit (a2-0) include monomers described in JP 2010-204634 A.
Among them, the structural unit (a2-0) is represented by formula (a2-0-1), formula (a2-0-2), formula (a2-0-3), and formula (a2-0-4), respectively. What is represented is preferable, and what is represented by a formula (a2-0-1) or a formula (a2-0-2) is more preferable.

  Resin (A) containing the structural unit (a2-0) is polymerized using a monomer in which the phenolic hydroxy group of the monomer that derives the structural unit (a2-0) is protected with a protective group such as an acetyl group. It can be produced by carrying out a reaction and then deprotecting. However, when the deprotection treatment is performed, the acid labile group of the structural unit (a1) needs to be not significantly impaired.

  When the resin (A) has the structural unit (a2-0), the content is preferably from 5 to 95 mol%, more preferably from 10 to 80 mol%, based on all the structural units of the resin (A). 15-80 mol% is more preferable.

式（ａ２−１）中、
Ｌ^a3は、−Ｏ−又は^＊−Ｏ−（ＣＨ₂）_k2−ＣＯ−Ｏ−を表し、
ｋ２は１〜７の整数を表す。＊は−ＣＯ−との結合手を表す。
Ｒ^a14は、水素原子又はメチル基を表す。
Ｒ^a15及びＲ^a16は、それぞれ独立に、水素原子、メチル基又はヒドロキシ基を表す。
ｏ１は、０〜１０の整数を表す。 Examples of the structural unit (a2) having an alcoholic hydroxy group include a structural unit represented by the formula (a2-1) (hereinafter sometimes referred to as “structural unit (a2-1)”).

In formula (a2-1),
L ^a3 represents —O— or ^* —O— (CH ₂ ) _k2 —CO—O—,
k2 represents an integer of 1 to 7. * Represents a bond with -CO-.
R ^a14 represents a hydrogen atom or a methyl group.
R ^a15 and R ^a16 each independently represent a hydrogen atom, a methyl group or a hydroxy group.
o1 represents an integer of 0 to 10.

In the formula (a2-1), L ^a3 is preferably, -O -, - O- (CH 2) f1 -CO-O- and is (wherein f1 is an integer from 1 to 4), more preferably Is —O—.
R ^a14 is preferably a methyl group.
R ^a15 is preferably a hydrogen atom.
R ^a16 is preferably a hydrogen atom or a hydroxy group.
o1 is preferably an integer of 0 to 3, more preferably 0 or 1.

Examples of the monomer that derives the structural unit (a2-1) include monomers described in JP 2010-204646 A. A monomer represented by any one of formula (a2-1-1) to formula (a2-1-6) is preferable, and represented by any one of formula (a2-1-1) to formula (a2-1-4). The monomer represented by Formula (a2-1-1) or Formula (a2-1-3) is more preferable.

  When resin (A) contains a structural unit (a2-1) structural unit, the content rate is 1-45 mol% normally with respect to all the structural units of resin (A), Preferably it is 1-40 mol. %, More preferably 1 to 35 mol%, and still more preferably 2 to 20 mol%.

<Structural unit (a3)>
The lactone ring of the structural unit (a3) may be, for example, a single ring such as a β-propiolactone ring, γ-butyrolactone ring, or δ-valerolactone ring, or a bridged ring including such a lactone ring structure. Good. Among these lactone rings, a γ-butyrolactone ring or a bridged ring containing a γ-butyrolactone ring structure is preferable.

  The structural unit (a3) is preferably a structural unit represented by the formula (a3-1), the formula (a3-2), or the formula (a3-3). These 1 type may be contained independently and 2 or more types may be contained.

［式（ａ３−１）中、
Ｌ^a4は、酸素原子又は^＊−Ｏ−（ＣＨ₂）_k3−ＣＯ−Ｏ−（ｋ３は１〜７の整数を表す。）で表される基を表す。＊はカルボニル基との結合手を表す。
Ｒ^a18は、水素原子又はメチル基を表す。
Ｒ^a21は炭素数１〜４の脂肪族炭化水素基を表す。
ｐ１は０〜５の整数を表す。ｐ１が２以上のとき、複数のＲ^a21は互いに同一又は相異なる。
式（ａ３−２）中、
Ｌ^a5は、酸素原子又は^＊−Ｏ−（ＣＨ₂）_k3−ＣＯ−Ｏ−（ｋ３は１〜７の整数を表す。）で表される基を表す。＊はカルボニル基との結合手を表す。
Ｒ^a19は、水素原子又はメチル基を表す。
Ｒ^a22は、カルボキシ基、シアノ基又は炭素数１〜４の脂肪族炭化水素基を表す。
ｑ１は、０〜３の整数を表す。ｑ１が２以上のとき、複数のＲ^a22は互いに同一又は相異なる。
式（ａ３−３）中、
Ｌ^a6は、酸素原子又は^＊−Ｏ−（ＣＨ₂）_k3−ＣＯ−Ｏ−（ｋ３は１〜７の整数を表す。）で表される基を表す。＊はカルボニル基との結合手を表す。
Ｒ^a20は、水素原子又はメチル基を表す。
Ｒ^a23は、カルボキシ基、シアノ基又は炭素数１〜４の脂肪族炭化水素基を表す。
ｒ１は、０〜３の整数を表す。ｒ１が２以上のとき、複数のＲ^a23は互いに同一又は相異なる。］

[In the formula (a3-1),
L ^a4 represents an oxygen atom or a group represented by ^* —O— (CH ₂ ) _k3 —CO—O— (k3 represents an integer of 1 to 7). * Represents a bond with a carbonyl group.
R ^a18 represents a hydrogen atom or a methyl group.
R ^a21 represents an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
p1 represents an integer of 0 to 5. When p1 is 2 or more, the plurality of R ^a21 are the same or different from each other.
In formula (a3-2),
L ^a5 represents an oxygen atom or a group represented by ^* —O— (CH ₂ ) _k3 —CO—O— (k3 represents an integer of 1 to 7). * Represents a bond with a carbonyl group.
R ^a19 represents a hydrogen atom or a methyl group.
R ^a22 represents a carboxy group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
q1 represents an integer of 0 to 3. When q1 is 2 or more, the plurality of R ^a22 are the same or different from each other.
In formula (a3-3),
L ^a6 represents an oxygen atom or a group represented by ^* —O— (CH ₂ ) _k3 —CO—O— (k3 represents an integer of 1 to 7). * Represents a bond with a carbonyl group.
R ^a20 represents a hydrogen atom or a methyl group.
R ^a23 represents a carboxy group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
r1 represents an integer of 0 to 3. When r1 is 2 or more, the plurality of R ^a23 are the same or different from each other. ]

In the formula (a3-1) to the formula (a3-3), L ^{a4 to} L ^a6 are each independently preferably an oxygen atom or * —O— (CH ₂ ) in which k3 is an integer of 1 to 4. A group represented by _{k 3} —CO—O—, more preferably an oxygen atom and * —O—CH ₂ —CO—O—, still more preferably an oxygen atom.
R ^{a18 to} R ^a21 are preferably methyl groups.
R ^a22 and R ^a23 are each independently preferably a carboxy group, a cyano group or a methyl group.
p1, q1, and r1 are each independently preferably an integer of 0-2.

  Examples of the monomer that leads to the structural unit (a3) include monomers described in JP 2010-204646 A. Formula (a3-1-1) to Formula (a3-1-6), Formula (a3-2-1) to Formula (a3-2-4), and Formula (a3-3-1) to Formula (a3-3) -4) is preferred, and the monomers represented by formula (a3-1-1) to formula (a3-1-2) and formula (a3-2-3) to formula (a3-2-4) are preferred. The monomer represented by either is more preferable, and the monomer represented by the formula (a3-1-1) or the formula (a3-2-3) is more preferable.

When the resin (A2) contains the structural unit (a3), the content is usually 5 to 70 mol%, preferably 10 to 65 mol%, based on all the structural units of the resin (A2). More preferably, it is 10-60 mol%.
Further, the content of the structural unit (a3-1), the structural unit (a3-2), and the structural unit (a3-3) is 5 to 60 mol% with respect to all the structural units of the resin (A). Preferably, 5-50 mol% is more preferable, and 10-50 mol% is further more preferable.

<Other structural units (s)>
Examples of the structural unit (s) include a structural unit having a halogen atom in addition to the structural unit (a2) and the structural unit (a3) (hereinafter sometimes referred to as “structural unit (a4)”).

［式（ａ４−１）中、
Ｒ^a41は、水素原子又はメチル基を表す。
Ａ^a41は、置換基を有していてもよい炭素数１〜６のアルカンジイル基又は式（ａ−ｇ１）

〔式（ａ−ｇ１）中、
ｓは０又は１を表す。
Ａ^a42及びＡ^a44は、それぞれ独立に、置換基を有していてもよい炭素数１〜５の脂肪族炭化水素基を表す。
Ａ^a43は、置換基を有していてもよい炭素数１〜５の脂肪族炭化水素基又は単結合を表す。
Ｘ^a41及びＸ^a42は、それぞれ独立に、−Ｏ−、−ＣＯ−、−ＣＯ−Ｏ−又は−Ｏ−ＣＯ−を表す。
ただし、Ａ^a42、Ａ^a43、Ａ^a44、Ｘ^a41及びＸ^a42の炭素数の合計は６以下である。〕
で表される基を表す。
Ｒ^a42は、置換基を有していてもよい炭素数１〜２０の炭化水素基を表す。
ただし、Ａ^a41及びＲ^a４２のうち少なくとも一方は、ハロゲン原子を有する基である。］ As a structural unit (a4), the structural unit represented by a formula (a4-1) is mentioned, for example.

[In the formula (a4-1),
R ^a41 represents a hydrogen atom or a methyl group.
A ^a41 is an alkanediyl group having 1 to 6 carbon atoms which may have a substituent or a formula (a-g1).

[In the formula (a-g1),
s represents 0 or 1.
A ^a42 and A ^a44 each independently represent an ^optionally substituted aliphatic hydrocarbon group having 1 to 5 carbon atoms.
A ^a43 represents an aliphatic hydrocarbon group having 1 to 5 carbon atoms which may have a substituent or a single bond.
X ^a41 and X ^a42 each independently represent —O—, —CO—, ^—CO —O— or —O—CO—.
However, the total number of carbon atoms of A ^a42 , A ^a43 , A ^a44 , X ^a41 and X ^a42 is 6 or less. ]
Represents a group represented by
R ^a42 represents an ^optionally substituted hydrocarbon group having 1 to 20 carbon atoms.
However, at least one of A ^a41 and R ^a42 is a group having a halogen atom. ]

As a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom are mentioned, Preferably it is a fluorine atom.
The aliphatic hydrocarbon group may have a carbon-carbon unsaturated bond, but is preferably an aliphatic saturated hydrocarbon group. Examples of the aliphatic saturated hydrocarbon group include an alkyl group (the alkyl group may be linear or branched), an alicyclic hydrocarbon group, and an aliphatic combination of an alkyl group and an alicyclic hydrocarbon group. Group hydrocarbon group and the like.

芳香族炭化水素基としては、例えば、フェニル基、ナフチル基、アントリル基、ビフェニリル基、フェナントリル基及びフルオレニル基等が挙げられる。 ^Examples of the hydrocarbon group for R ^a42 include chain and cyclic aliphatic hydrocarbon groups, aromatic hydrocarbon groups, and groups in which these are combined. Examples of chain aliphatic hydrocarbon groups include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, decyl, dodecyl, hexadecyl, pentadecyl, and hexyl. A decyl group, a heptadecyl group, an octadecyl group, etc. are mentioned. Examples of the cyclic aliphatic hydrocarbon group include a cycloalkyl group such as a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group; a decahydronaphthyl group, an adamantyl group, a norbornyl group, and the following groups (* Represents a bond, and the like.) A polycyclic alicyclic hydrocarbon group such as a polycyclic alicyclic hydrocarbon group.

Examples of the aromatic hydrocarbon group include a phenyl group, a naphthyl group, an anthryl group, a biphenylyl group, a phenanthryl group, and a fluorenyl group.

［式（ａ−ｇ３）中、
Ｘ^a43は、酸素原子、カルボニル基、カルボニルオキシ基又はオキシカルボニル基を表す。
Ａ^a45は、少なくとも１つのハロゲン原子を有する炭素数３〜１７の脂肪族炭化水素基を表す。］
Ｒ^a4２が、式（ａ−ｇ３）で表される基を有する脂肪族炭化水素基である場合、式（ａ−ｇ３）で表される基に含まれる炭素数を含めて、脂肪族炭化水素基の総炭素数は、１５以下が好ましく、１２以下がより好ましい。式（ａ−ｇ３）で表される基を置換基として有する場合、その数は１個が好ましい。 The hydrocarbon group for R ^a42 is preferably a chain or cyclic aliphatic hydrocarbon group or a group in which these are combined, and may have a carbon-carbon unsaturated bond. Of these, aliphatic saturated hydrocarbon groups and combinations thereof are more preferred. Specifically, the same group as R ^a41 is ^exemplified .
R ^a42 is preferably an aliphatic hydrocarbon group, and more preferably an aliphatic hydrocarbon group having a halogen atom and / or a group represented by the formula (a-g3).

[In the formula (a-g3),
X ^a43 represents an oxygen atom, a carbonyl group, a carbonyloxy group or an oxycarbonyl group.
A ^a45 represents a C ^3-17 aliphatic hydrocarbon group having at least one halogen atom. ]
When R ^a42 is an aliphatic hydrocarbon group having a group represented by the formula (a-g3), including the number of carbons contained in the group represented by the formula (a-g3), the aliphatic hydrocarbon The total carbon number of the group is preferably 15 or less, more preferably 12 or less. When it has a group represented by the formula (a-g3) as a substituent, the number is preferably 1.

［式（ａ−ｇ２）中、
Ａ^a46は、ハロゲン原子を有していてもよい炭素数３〜１７の脂肪族炭化水素基を表す。
Ｘ^a44は、カルボニルオキシ基又はオキシカルボニル基を表す。
Ａ^a47は、ハロゲン原子を有していてもよい炭素数３〜１７の脂肪族炭化水素基を表す。
ただし、Ａ^a46、Ａ^a47及びＸ^a44の炭素数の合計は１８以下であり、Ａ^a46及びＡ^a47のうち、少なくとも一方は、少なくとも１つのハロゲン原子を有する。］ The aliphatic hydrocarbon having a group represented by the formula (a-g3) is more preferably a group represented by the formula (a-g2).

[In the formula (a-g2),
A ^a46 represents an aliphatic hydrocarbon group having 3 to 17 carbon atoms which may have a halogen atom.
X ^a44 represents a carbonyloxy group or an oxycarbonyl group.
A ^a47 represents an aliphatic hydrocarbon group having 3 to 17 carbon atoms which may have a halogen atom.
However, the total number of carbon atoms of A ^a46 , A ^a47, and X ^a44 is 18 or less, and at least one of A ^a46 and A ^a47 has at least one halogen atom. ]

Preferred R ^a42 , an aliphatic hydrocarbon group having a substituent selected from the group consisting of a halogen atom and a group represented by formula (a-g3) (a group represented by formula (a-g2)) Detailed description.

When R ^a42 is an aliphatic hydrocarbon group having a halogen atom, it is preferably an aliphatic hydrocarbon group having a fluorine atom, more preferably a perfluoroalkyl group or a perfluorocycloalkyl group, and still more preferably a carbon number. It is a 1-6 perfluoroalkyl group, Most preferably, it is a C1-C3 perfluoroalkyl group. Examples of the perfluoroalkyl group include a perfluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluorobutyl group, a perfluoropentyl group, a perfluorohexyl group, a perfluoroheptyl group, and a perfluorooctyl group. Examples of the perfluorocycloalkyl group include a perfluorocyclohexyl group.

1-6 are preferable and, as for carbon number of the aliphatic hydrocarbon group of ^Aa46 , 1-3 are more preferable.
4-15 are preferable, as for carbon number of the aliphatic hydrocarbon group of A ^<a47> , 5-12 are more preferable, and A ^<a47> has a more preferable cyclohexyl group or an adamantyl group.

Among the combinations of A ^a46 and A ^a47, the more preferable, * - is represented by the partial structure represented by A ^a46 -X ^a44 -A ^a47 (* represents a bond to a carbonyl group), the following structure Is mentioned.

^As the alkanediyl group of ^Aa41 , a methylene group, an ethylene group, a propane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group Linear alkanediyl group such as propane-1,2-diyl group, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group And branched alkanediyl groups such as 1-methylbutane-1,4-diyl group and 2-methylbutane-1,4-diyl group.
^Examples of the substituent in the alkanediyl group of A ^a41 include a hydroxy group and an alkoxy group having 1 to 6 carbon atoms.
A ^a41 is preferably an alkanediyl group having 1 to 4 carbon atoms, more preferably an alkanediyl group having 2 to 4 carbon atoms, and still more preferably an ethylene group.

In the group represented by the formula (a-g1) of A ^a41 (hereinafter sometimes referred to as “group (a-g1)”), A ^a44 is ^bonded to —O—CO—R ^a42 .
As the aliphatic hydrocarbon group for A ^a42 , A ^a43 and A ^{a44 in} the group (a-g1), a methylene group, an ethylene group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane- Examples include 1,4-diyl group, 1-methylpropane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group and the like. Examples of these substituents include a hydroxy group and an alkoxy group having 1 to 6 carbon atoms.

^Examples of the group (a-g1) in which X ^a42 is an oxygen atom include the following groups. In the following examples, among the two bonds represented by *, * on the right side is a bond with —O—CO—R ^a42 .

Examples of the group (a-g1) in which X ^a42 is a carbonyl group include the following groups.

Examples of the group (a-g1) in which X ^a42 is a carbonyloxy group include the following groups.

Examples of the group (a-g1) in which X ^a42 is an oxycarbonyl group include the following groups.

［式（ａ４−２）中、
Ｒ^ｆ1は、水素原子又はメチル基を表す。
Ａ^ｆ1は、炭素数１〜６のアルカンジイル基を表す。
Ｒ^ｆ2は、フッ素原子を有する炭素数１〜１０の炭化水素基を表す。］ As the structural unit represented by the formula (a4-1), a structural unit represented by the formula (a4-2) or the formula (a4-3) is preferable.

[In the formula (a4-2),
R ^f1 represents a hydrogen atom or a methyl group.
A ^f1 represents an alkanediyl group having 1 to 6 carbon atoms.
R ^f2 represents a C 1-10 hydrocarbon group having a fluorine atom. ]

As the alkanediyl group of A ^f1 , a methylene group, an ethylene group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group , A straight-chain alkanediyl group such as hexane-1,6-diyl group; 1-methylpropane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2 -Branched alkanediyl groups such as a diyl group, 1-methylbutane-1,4-diyl group, 2-methylbutane-1,4-diyl group.

The hydrocarbon group for R ^f2 includes an aliphatic hydrocarbon group and an aromatic hydrocarbon group, and the aliphatic hydrocarbon group includes a chain group, a cyclic group, and a combination thereof. As the aliphatic hydrocarbon group, an alkyl group and an alicyclic hydrocarbon group are preferable.
Examples of the alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, octyl group and 2-ethylhexyl group. .
The alicyclic hydrocarbon group may be monocyclic or polycyclic, and examples of the monocyclic alicyclic hydrocarbon group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a methyl group. Examples thereof include cycloalkyl groups such as cyclohexyl group, dimethylcyclohexyl group, cycloheptyl group, cyclooctyl group, cycloheptyl group, and cyclodecyl group. Examples of the polycyclic alicyclic hydrocarbon group include decahydronaphthyl group, adamantyl group, 2-alkyladamantan-2-yl group, 1- (adamantan-1-yl) alkane-1-yl group, and norbornyl. Group, methylnorbornyl group and isobornyl group.

Examples of the hydrocarbon group having a fluorine atom for R ^f2 include an alkyl group having a fluorine atom and an alicyclic hydrocarbon group having a fluorine atom.
Specifically, examples of the alkyl group having a fluorine atom include a difluoromethyl group, a trifluoromethyl group, a 1,1-difluoroethyl group, a 2,2-difluoroethyl group, a 2,2,2-trifluoroethyl group, Perfluoroethyl group, 1,1,2,2-tetrafluoropropyl group, 1,1,2,2,3,3-hexafluoropropyl group, perfluoroethylmethyl group, 1- (trifluoromethyl) -1,2 , 2,2-tetrafluoroethyl group, perfluoropropyl group, 1,1,2,2-tetrafluorobutyl group, 1,1,2,2,3,3-hexafluorobutyl group, 1,1,2, 2,3,3,4,4-octafluorobutyl group, perfluorobutyl group, 1,1-bis (trifluoro) methyl-2,2,2-trifluoroethyl group, 2- (perfluoro (Ropropyl) ethyl group, 1,1,2,2,3,3,4,4-octafluoropentyl group, perfluoropentyl group, 1,1,2,2,3,3,4,4,5,5- Decafluoropentyl group, 1,1-bis (trifluoromethyl) -2,2,3,3,3-pentafluoropropyl group, perfluoropentyl group, 2- (perfluorobutyl) ethyl group, 1,1,2, 2,3,3,4,4,5,5-decafluorohexyl group, 1,1,2,2,3,3,4,4,5,5,6,6-dodecafluorohexyl group, perfluoropentyl Examples thereof include fluorinated alkyl groups such as a methyl group and a perfluorohexyl group.
Examples of the alicyclic hydrocarbon group having a fluorine atom include fluorinated cycloalkyl groups such as a perfluorocyclohexyl group and a perfluoroadamantyl group.

In formula (a4-2), an alkanediyl group having 2 to 4 carbon atoms is preferable, and as A ^f1 , an ethylene group is more preferable.
R ^f2 is preferably a fluorinated alkyl group having 1 to 6 carbon atoms.

［式（ａ４−３）中、
Ｒ^ｆ11は、水素原子又はメチル基を表す。
Ａ^ｆ11は、炭素数１〜６のアルカンジイル基を表す。
Ａ^ｆ13は、フッ素原子を有していてもよい炭素数１〜１８の脂肪族炭化水素基を表す。
Ｘ^ｆ12は、カルボニルオキシ基又はオキシカルボニル基を表す。
Ａ^ｆ14は、フッ素原子を有していてもよい炭素数１〜１７の脂肪族炭化水素基を表す。 ただし、Ａ^ｆ13及びＡ^ｆ14の少なくとも１つは、フッ素原子を有する脂肪族炭化水素基を表す。］

[In the formula (a4-3),
R ^f11 represents a hydrogen atom or a methyl group.
A ^f11 represents an alkanediyl group having 1 to 6 carbon atoms.
A ^f13 represents an aliphatic hydrocarbon group having 1 to 18 carbon atoms which may have a fluorine atom.
X ^f12 represents a carbonyloxy group or an oxycarbonyl group.
A ^f14 represents an aliphatic hydrocarbon group having 1 to 17 carbon atoms which may have a fluorine atom. However, at least one of A ^f13 and A ^f14 represents an aliphatic hydrocarbon group having a fluorine atom. ]

^Examples of the alkanediyl group for A ^f11 include the same groups as the alkanediyl group for A ^f1 .

The aliphatic hydrocarbon group for A ^f13 includes either a chain or a cyclic group, and a divalent aliphatic hydrocarbon group in which these are combined. The aliphatic hydrocarbon may have a carbon-carbon unsaturated bond, but is preferably a saturated aliphatic hydrocarbon group.
The aliphatic hydrocarbon group which may have a fluorine atom of A ^f13 is preferably an aliphatic saturated hydrocarbon group which may have a fluorine atom, and more preferably a perfluoroalkanediyl group.
Examples of the divalent chain aliphatic hydrocarbon group which may have a fluorine atom include alkanediyl groups such as methylene group, ethylene group, propanediyl group, butanediyl group and pentanediyl group; difluoromethylene group, perfluoroethylene Groups, perfluoroalkanediyl groups such as perfluoropropanediyl group, perfluorobutanediyl group and perfluoropentanediyl group.
The divalent cyclic aliphatic hydrocarbon group which may have a fluorine atom may be either monocyclic or polycyclic. Examples of the monocyclic aliphatic hydrocarbon group include a cyclohexanediyl group and a perfluorocyclohexanediyl group. Examples of the polycyclic divalent aliphatic hydrocarbon group include an adamantanediyl group, a norbornanediyl group, a perfluoroadamantanediyl group, and the like.

As the aliphatic hydrocarbon group for A ^f14 , either a chain or a cyclic group, and an aliphatic hydrocarbon group in which these are combined are included. The aliphatic hydrocarbon may have a carbon-carbon unsaturated bond, but is preferably a saturated aliphatic hydrocarbon group.
The aliphatic hydrocarbon group which may have a fluorine atom for A ^f14 is preferably an aliphatic saturated hydrocarbon group which may have a fluorine atom.
Examples of the chain aliphatic hydrocarbon group which may have a fluorine atom include a trifluoromethyl group, a difluoromethyl group, a methyl group, a perfluoroethyl group, a 1,1,1-trifluoroethyl group, 1,1 , 2,2-tetrafluoroethyl group, ethyl group, perfluoropropyl group, 1,1,1,2,2-pentafluoropropyl group, propyl group, perfluorobutyl group, 1,1,2,2,3,3 , 4,4-octafluorobutyl group, butyl group, perfluoropentyl group, 1,1,1,2,2,3,3,4,4-nonafluoropentyl group and pentyl group, hexyl group, perfluorohexyl group, A heptyl group, a perfluoro heptyl group, an octyl group, a perfluorooctyl group, etc. are mentioned.
Etc.
The cyclic aliphatic hydrocarbon group which may have a fluorine atom may be monocyclic or polycyclic. Examples of the group containing a monocyclic aliphatic hydrocarbon group include a cyclopropylmethyl group, a cyclopropyl group, a cyclobutylmethyl group, a cyclopentyl group, a cyclohexyl group, and a perfluorocyclohexyl group. Examples of the group containing a polycyclic aliphatic hydrocarbon group include an adamantyl group, an adamantylmethyl group, a norbornyl group, a norbornylmethyl group, a perfluoroadamantyl group, and a perfluoroadamantylmethyl group.

In the formula (a4-3), examples of ^{A f11,} ethylene group is preferable.
The aliphatic hydrocarbon group for A ^f13 preferably has 1 to 6 carbon atoms, more preferably 2 to 3 carbon atoms.
The aliphatic hydrocarbon group for A ^f14 preferably has 3 to 12 carbon atoms, and more preferably 3 to 10 carbon atoms. Among them, A ^f14 is preferably a group containing an alicyclic hydrocarbon group having 3 to 12 carbon atoms, and more preferably a cyclopropylmethyl group, a cyclopentyl group, a cyclohexyl group, a norbornyl group, and an adamantyl group.

Examples of the monomer for deriving the structural unit represented by formula (a4-2) include monomers represented by formula (a4-1-1) to formula (a4-1-22), respectively.

Examples of the monomer for deriving the structural unit represented by formula (a4-3) include monomers represented by formula (a4-1′-1) to formula (a4-1′-22), respectively.

［式（ａ４−４）中、
Ｒ^f21は、水素原子又はメチル基を表す。
Ａ^f21は、−（ＣＨ_２）_ｊ１−、−（ＣＨ_２）_ｊ２−Ｏ−（ＣＨ_２）_ｊ３−又は−（ＣＨ_２）_ｊ４−ＣＯ−Ｏ−（ＣＨ_２）_ｊ５−を表す。
ｊ１〜ｊ５は、それぞれ独立に、１〜６の整数を表す。
Ｒ^f22は、フッ素原子を有する炭素数１〜１０の炭化水素基を表す。］ Examples of the structural unit (a4) include a structural unit represented by the formula (a4-4).

[In the formula (a4-4),
R ^f21 represents a hydrogen atom or a methyl group.
A ^f21 represents — (CH ₂ ) _j1 —, — (CH ₂ ) _j2 —O— (CH ₂ ) _j3 — or — (CH ₂ ) _j4 —CO—O— (CH ₂ ) _j5 —.
j1 to j5 each independently represents an integer of 1 to 6.
R ^f22 represents a C 1-10 hydrocarbon group having a fluorine atom. ]

^Examples of the hydrocarbon group having a fluorine atom of R ^f22 include the same hydrocarbon groups as R ^f2 in formula (a4-2). R ^f22 is preferably a ^C 1-10 alkyl group having a fluorine atom or a C 1-10 alicyclic hydrocarbon group having a fluorine atom, more preferably a C 1-10 alkyl group having a fluorine atom. Preferably, the C1-C6 alkyl group which has a fluorine atom is further more preferable.

In Formula (a4-4), as A ^f21 , — (CH ₂ ) _j1 — is preferable, an ethylene group or a methylene group is more preferable, and a methylene group is further preferable.

Examples of the monomer for deriving the structural unit represented by the formula (a4-4) include the following monomers.

  When the resin (A) has a structural unit (a4), the content is preferably 1 to 20 mol%, more preferably 2 to 15 mol%, based on all structural units of the resin (A). More preferably, it is 10 mol%.

  The resin (A) may have a structural unit other than the above-described structural unit, and examples of the structural unit include structural units well known in the art.

The resin (A) is preferably a resin composed of the structural unit (a1) and the structural unit (s). In this case, each of these contents is based on all structural units of the resin (A).
Structural unit (a1); 10-95 mol%
Structural unit (s); 5-90 mol%
Is preferred,
Structural unit (a1); 15 to 90 mol%
Structural unit (s); 10-85 mol%
Is more preferred,
Structural unit (a1); 20 to 85 mol%
Structural unit (s); 15-80 mol%
Is more preferable.

The structural unit (a1) is preferably at least one of the structural unit (a1-1) and the structural unit (a1-2) (preferably the structural unit having a cyclohexyl group or a cyclopentyl group), more preferably the structural unit (a1- 1).
The structural unit (s) is preferably at least one of the structural unit (a2) and the structural unit (a3). The structural unit (a2) is preferably a structural unit represented by the formula (a2-1). The structural unit (a3) is preferably at least one of a structural unit represented by the formula (a3-1) and a structural unit represented by the formula (a3-2).

  The resin (A) may contain a structural unit derived from a monomer having an adamantyl group (particularly the structural unit (a1-1)) in an amount of 15 mol% or more based on the content of the structural unit (a1). preferable. When the content of the structural unit having an adamantyl group is increased, the dry etching resistance of the resist pattern is improved.

Each structural unit constituting the resin (A) may be used alone or in combination of two or more, and is produced by a known polymerization method (for example, radical polymerization method) using a monomer that derives these structural units. can do. The content rate of each structural unit which resin (A) has can be adjusted with the usage-amount of the monomer used for superposition | polymerization.
The weight average molecular weight of the resin (A) is preferably 2,500 or more (more preferably 3,000 or more, more preferably 4,000 or more), 50,000 or less (more preferably 30,000 or less, and further preferably 15,000 or less).

<Resin other than resin (A)>
The resist composition of the present invention may contain a resin other than the resin (A). An example of such a resin is a resin composed of only the structural unit (s).
Especially, as resin other than resin (A), resin (henceforth "resin (X)") which has structural unit (a4) is preferable. In the resin (X), the content ratio of the structural unit (a4) is preferably 80 mol% or more, more preferably 85 mol% or more, and still more preferably 90 mol% or more with respect to all the structural units of the resin (X). .
Examples of the structural unit that the resin (X) may further include, for example, a structural unit derived from the monomer (a2), a structural unit derived from the monomer (a3), and a structural unit derived from other known monomers. Can be mentioned.
The weight average molecular weight of the resin (X) is preferably 8,000 or more (more preferably 10,000 or more) and 80,000 or less (more preferably 60,000 or less). The means for measuring the weight average molecular weight of the resin (X) is the same as that for the resin (A).

  When the resist composition of this invention contains resin (X), the content becomes like this. Preferably it is 1-60 mass parts with respect to 100 mass parts of resin (A), More preferably, it is 3-50 mass parts More preferably, it is 5-40 mass parts, Most preferably, it is 7-30 mass parts.

  The resin content in the resist composition of the present invention is preferably 80% by mass or more and 99% by mass or less with respect to the solid content of the resist composition. In the present specification, the “solid content of the resist composition” means the total of components excluding the solvent (D) described later from the total amount of the resist composition. The solid content of the resist composition and the resin content relative to the solid content can be measured, for example, by known analytical means such as liquid chromatography or gas chromatography.

<Solvent (D)>
The content of the solvent (D) is, for example, 90% by mass or more in the resist composition, preferably 92% by mass or more, more preferably 94% by mass or more, for example 99.9% by mass or less, preferably 99% by mass or less. It is. The content rate of a solvent (D) can be measured with well-known analysis means, such as a liquid chromatography or a gas chromatography, for example.

  Examples of the solvent (D) include glycol ether esters such as ethyl cellosolve acetate, methyl cellosolve acetate and propylene glycol monomethyl ether acetate; glycol ethers such as propylene glycol monomethyl ether; ethyl lactate, butyl acetate, amyl acetate and And esters such as ethyl pyruvate; ketones such as acetone, methyl isobutyl ketone, 2-heptanone and cyclohexanone; cyclic esters such as γ-butyrolactone; A solvent (D) may contain individually by 1 type and may contain 2 or more types.

<Basic compound (C)>
The basic compound (C) is preferably a basic nitrogen-containing organic compound, and examples thereof include amines and ammonium salts. Examples of amines include aliphatic amines and aromatic amines. Aliphatic amines include primary amines, secondary amines and tertiary amines. The basic compound (C) is preferably a compound represented by any one of the formulas (C1) to (C8) and (C1-1), more preferably represented by the formula (C1-1). The compound which is made is mentioned.

［式（Ｃ１）中、Ｒ^c1、Ｒ^c2及びＲ^c3は、それぞれ独立に、水素原子、炭素数１〜６のアルキル基、炭素数５〜１０の脂環式炭化水素基又は炭素数６〜１０の芳香族炭化水素基を表し、該アルキル基及び該脂環式炭化水素基に含まれる水素原子は、ヒドロキシ基、アミノ基又は炭素数１〜６のアルコキシ基で置換されていてもよく、該芳香族炭化水素基に含まれる水素原子は、炭素数１〜６のアルキル基、炭素数１〜６のアルコキシ基、炭素数５〜１０の脂環式炭化水素又は炭素数６〜１０の芳香族炭化水素基で置換されていてもよい。］

[In formula (C1), R ^c1 , R ^c2 and R ^c3 each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alicyclic hydrocarbon group having 5 to 10 carbon atoms, or 6 to 6 carbon atoms. 10 represents an aromatic hydrocarbon group, and the hydrogen atom contained in the alkyl group and the alicyclic hydrocarbon group may be substituted with a hydroxy group, an amino group or an alkoxy group having 1 to 6 carbon atoms, The hydrogen atom contained in the aromatic hydrocarbon group is an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alicyclic hydrocarbon having 5 to 10 carbon atoms, or an aromatic group having 6 to 10 carbon atoms. It may be substituted with a group hydrocarbon group. ]

［式（Ｃ１−１）中、Ｒ^c2及びＲ^c3は、上記と同じ意味を表す。
Ｒ^c4は、炭素数１〜６のアルキル基、炭素数１〜６のアルコキシ基、炭素数５〜１０の脂環式炭化水素又は炭素数６〜１０の芳香族炭化水素基を表す。
ｍ３は０〜３の整数を表し、ｍ３が２以上のとき、複数のＲ^c4は同一又は相異なる。］ The compound represented by the formula (C1) is preferably a compound represented by the formula (C1-1).

[In Formula (C1-1), R ^c2 and R ^c3 represent the same meaning as described above.
R ^c4 represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alicyclic hydrocarbon having 5 to 10 carbon atoms, or an aromatic hydrocarbon group having 6 to 10 carbon atoms.
m3 represents an integer of 0 to 3, and when m3 is 2 or more, the plurality of R ^c4 are the same or different. ]

［式（Ｃ２）、式（Ｃ３）及び式（Ｃ４）中、Ｒ^c5、Ｒ^c6、Ｒ^c7及びＲ^c8は、それぞれ独立に、Ｒ^c1と同じ意味を表す。
Ｒ^c9は、炭素数１〜６のアルキル基、炭素数３〜６の脂環式炭化水素基又は炭素数２〜６のアルカノイル基を表す。
ｎ３は０〜８の整数を表し、ｎ３が２以上のとき、複数のＲ^c9は同一又は相異なる。］

[In Formula (C2), Formula (C3) and Formula (C4), R ^c5 , R ^c6 , R ^c7 and R ^c8 each independently represent the same meaning as R ^c1 .
R ^c9 represents an alkyl group having 1 to 6 carbon atoms, an alicyclic hydrocarbon group having 3 to 6 carbon atoms, or an alkanoyl group having 2 to 6 carbon atoms.
n3 represents an integer of 0 to 8, and when n3 is 2 or more, the plurality of R ^c9 are the same or different. ]

［式（Ｃ５）及び式（Ｃ６）中、Ｒ^c10、Ｒ^c11、Ｒ^c12、Ｒ^c13及びＲ^c16は、それぞれ独立に、Ｒ^c1と同じ意味を表す。
Ｒ^c14、Ｒ^c15及びＲ^c17は、それぞれ独立に、Ｒ^c4と同じ意味を表す。
ｏ３及びｐ３は、それぞれ独立に０〜３の整数を表し、ｏ３が２以上のとき、複数のＲ^c1４は同一又は相異なり、ｐ３が２以上のとき、複数のＲ^c15は、同一又は相異なる。
Ｌ^c1は、炭素数１〜６のアルカンジイル基、−ＣＯ−、−Ｃ（＝ＮＨ）−、−Ｓ−又はこれらを組合せた２価の基を表す。］

[In Formula (C5) and Formula (C6), R ^c10 , R ^c11 , R ^c12 , R ^c13 and R ^c16 each independently represent the same meaning as R ^c1 .
R ^c14 , R ^c15 and R ^c17 each independently represent the same meaning as R ^c4 .
o3 and p3 each independently represent an integer of 0 to ^3. When o3 is 2 or more, the plurality of R ^c14 are the same or different, and when p3 is 2 or more, the plurality of R ^c15 are the same or different. .
L ^c1 represents an alkanediyl group having 1 to 6 carbon atoms, —CO—, —C (═NH) —, —S—, or a divalent group obtained by combining these. ]

［式（Ｃ７）及び式（Ｃ８）中、Ｒ^c18、Ｒ^c19及びＲ^c20は、それぞれ独立に、Ｒ^c4と同じ意味を表す。
ｑ３、ｒ３及びｓ３は、それぞれ独立に０〜３の整数を表し、ｑ３が２以上のとき、複数のＲ^c18は同一又は相異なり、ｒ３が２以上のとき、複数のＲ^c1９は同一又は相異なり、及びｓ３が２以上のとき、複数のＲ^c20は同一又は相異なる。
Ｌ^c2は、単結合又は炭素数１〜６のアルカンジイル基、−ＣＯ−、−Ｃ（＝ＮＨ）−、−Ｓ−又はこれらを組合せた２価の基を表す。］

Wherein (C7) and formula ^{(C8), R c18, R} c19 and R ^c20 in each occurrence independently represent the same meaning as R ^c4.
q3, r3 and s3 each independently represents an integer of 0 to 3, and when q3 is 2 or more, a plurality of R ^c18 are the same or different, and when r3 is 2 or more, a plurality of R ^c19 are the same or different. And when s3 is 2 or more, the plurality of R ^c20 are the same or different.
L ^c2 represents a single bond or an alkanediyl group having 1 to 6 carbon atoms, —CO—, —C (═NH) —, —S—, or a divalent group obtained by combining these. ]

In formula (C1) to formula (C8) and formula (C1-1), the alkyl group, alicyclic hydrocarbon group, aromatic hydrocarbon group, alkoxy group, alkanediyl group are the same as those described above. Is mentioned.
Examples of the alkanoyl group include acetyl group, 2-methylacetyl group, 2,2-dimethylacetyl group, propionyl group, butyryl group, isobutyryl group, pentanoyl group, and 2,2-dimethylpropionyl group.

  Examples of the compound represented by the formula (C1) include 1-naphthylamine, 2-naphthylamine, aniline, diisopropylaniline, 2-, 3- or 4-methylaniline, 4-nitroaniline, N-methylaniline, N, N- Dimethylaniline, diphenylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, triethylamine, trimethylamine, tripropylamine, tributylamine, tri Pentylamine, trihexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, methyldibutylamine, methyldipentylamine, methyl Hexylamine, methyldicyclohexylamine, methyldiheptylamine, methyldioctylamine, methyldinonylamine, methyldidecylamine, ethyldibutylamine, ethyldipentylamine, ethyldihexylamine, ethyldiheptylamine, ethyldioctylamine, ethyldinonyl Amine, ethyldidecylamine, dicyclohexylmethylamine, tris [2- (2-methoxyethoxy) ethyl] amine, triisopropanolamine, ethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4′-diamino-1,2- Examples include diphenylethane, 4,4′-diamino-3,3′-dimethyldiphenylmethane, 4,4′-diamino-3,3′-diethyldiphenylmethane, and preferably diisopropyl. Piruanirin. Particularly preferred include 2,6-diisopropylaniline.

Examples of the compound represented by the formula (C2) include piperazine.
Examples of the compound represented by the formula (C3) include morpholine.
Examples of the compound represented by the formula (C4) include piperidine and hindered amine compounds having a piperidine skeleton described in JP-A No. 11-52575.
Examples of the compound represented by the formula (C5) include 2,2′-methylenebisaniline.
Examples of the compound represented by the formula (C6) include imidazole and 4-methylimidazole.
Examples of the compound represented by the formula (C7) include pyridine and 4-methylpyridine.
Examples of the compound represented by the formula (C8) include 1,2-di (2-pyridyl) ethane, 1,2-di (4-pyridyl) ethane, 1,2-di (2-pyridyl) ethene, 1, 2-di (4-pyridyl) ethene, 1,3-di (4-pyridyl) propane, 1,2-di (4-pyridyloxy) ethane, di (2-pyridyl) ketone, 4,4′-dipyridyl sulfide 4,4′-dipyridyl disulfide, 2,2′-dipyridylamine, 2,2′-dipiconylamine, bipyridine and the like.

  As ammonium salts, tetramethylammonium hydroxide, tetraisopropylammonium hydroxide, tetrabutylammonium hydroxide, tetrahexylammonium hydroxide, tetraoctylammonium hydroxide, phenyltrimethylammonium hydroxide, 3- (trifluoromethyl) phenyltrimethyl Ammonium hydroxide, tetra-n-butylammonium salicylate, choline and the like can be mentioned.

  The content of the basic compound (C) in the solid content of the resist composition is preferably about 0.01 to 5% by mass, more preferably about 0.01 to 3% by mass, and particularly preferably 0.8. It is about 01 to 1% by mass.

<Other ingredients>
The resist composition of the present invention may contain components other than the above components (hereinafter sometimes referred to as “other components (F)”) as necessary. The other component (F) is not particularly limited, and additives known in the resist field, such as sensitizers, dissolution inhibitors, surfactants, stabilizers, dyes, and the like can be used.

<Preparation of resist composition>
The resist composition of the present invention is prepared by mixing the resin and the acid generator of the present invention, and the solvent (D), basic compound (C) and other components (F) used as necessary. be able to. The mixing order is arbitrary and is not particularly limited. The temperature at the time of mixing can select an appropriate temperature range from the range of 10-40 degreeC according to the kind etc. of resin etc., the solubility with respect to solvents (D), such as resin. An appropriate mixing time can be selected from 0.5 to 24 hours depending on the mixing temperature. The mixing means is not particularly limited, and stirring and mixing can be used.
After mixing each component, it is preferable to filter using a filter having a pore size of about 0.003 to 0.2 μm.

<Method for producing resist pattern>
The method for producing a resist pattern of the present invention comprises:
(1) The process of apply | coating the resist composition of this invention on a board | substrate,
(2) The process of drying the composition after application | coating and forming a composition layer,
(3) a step of exposing the composition layer;
(4) a step of heating the composition layer after exposure, and (5) a step of developing the composition layer after heating.

  The resist composition can be applied onto the substrate by a commonly used apparatus such as a spin coater. Examples of the substrate include an inorganic substrate such as a silicon wafer. Before applying the resist composition, the substrate may be washed, or an antireflection film or the like may be formed on the substrate.

By drying the composition after coating, the solvent is removed and a composition layer is formed. Drying is performed, for example, by evaporating the solvent using a heating device such as a hot plate (so-called pre-baking), or using a decompression device. The heating temperature is preferably 50 to 200 ° C., for example, and the heating time is preferably 10 to 180 seconds, for example. The pressure during drying under reduced pressure is preferably about 1 to 1.0 × 10 ⁵ Pa.

The obtained composition layer is usually exposed using an exposure machine. The exposure machine may be an immersion exposure machine. At this time, exposure is usually performed through a mask corresponding to a required pattern. Exposure light sources include those that emit laser light in the ultraviolet region such as KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), F ₂ excimer laser (wavelength 157 nm), solid-state laser light source (YAG or semiconductor laser) Etc.) Using various types of laser light such as those that convert wavelength of laser light from the laser and emit harmonic laser light in the far ultraviolet region or vacuum ultraviolet region, those that irradiate electron beams or extreme ultraviolet light (EUV), etc. Can do. In this specification, the irradiation of these radiations may be collectively referred to as “exposure”. At the time of exposure, exposure is usually performed through a mask corresponding to a required pattern. When the exposure light source is an electron beam, exposure may be performed by direct drawing without using a mask.

  The composition layer after exposure is subjected to heat treatment (so-called post-exposure baking) in order to promote the deprotection reaction of the resin (A). The heating temperature is usually about 50 to 200 ° C, preferably about 70 to 150 ° C.

  The heated composition layer is usually developed using a developer using a developing device. Examples of the developing method include a dipping method, a paddle method, a spray method, and a dynamic dispensing method. The development temperature is preferably 5 to 60 ° C., for example, and the development time is preferably 5 to 300 seconds, for example. A positive resist pattern or a negative resist pattern can be produced by selecting the type of developer as follows.

When producing a positive resist pattern from the resist composition of the present invention, an alkaline developer is used as the developer. The alkaline developer may be various alkaline aqueous solutions used in this field. Examples thereof include an aqueous solution of tetramethylammonium hydroxide and (2-hydroxyethyl) trimethylammonium hydroxide (commonly called choline). The alkali developer may contain a surfactant.
It is preferable to wash the resist pattern with ultrapure water after development, and then remove the water remaining on the substrate and the pattern.

In the case of producing a negative resist pattern from the resist composition of the present invention, a developer containing an organic solvent as a developer (hereinafter sometimes referred to as “organic developer”) is used.
Organic solvents contained in the organic developer include ketone solvents such as 2-hexanone and 2-heptanone; glycol ether ester solvents such as propylene glycol monomethyl ether acetate; ester solvents such as butyl acetate; glycols such as propylene glycol monomethyl ether Examples include ether solvents; amide solvents such as N, N-dimethylacetamide; aromatic hydrocarbon solvents such as anisole.
In the organic developer, the content of the organic solvent is preferably 90% by mass or more and 100% by mass or less, more preferably 95% by mass or more and 100% by mass or less, and still more preferably only the organic solvent.
Among them, the organic developer is preferably a developer containing butyl acetate and / or 2-heptanone. In the organic developer, the total content of butyl acetate and 2-heptanone is preferably 50% by mass to 100% by mass, more preferably 90% by mass to 100% by mass, and substantially butyl acetate and / or 2 -More preferred is heptanone alone.
The organic developer may contain a surfactant. The organic developer may contain a trace amount of water.
At the time of development, the development may be stopped by substituting a solvent of a different type from the organic developer.

It is preferable to wash the developed resist pattern with a rinse solution. The rinsing liquid is not particularly limited as long as it does not dissolve the resist pattern, and a solution containing a general organic solvent can be used, and an alcohol solvent or an ester solvent is preferable.
After the cleaning, it is preferable to remove the rinse solution remaining on the substrate and the pattern.

<Application>
The resist composition of the present invention includes a resist composition for KrF excimer laser exposure, a resist composition for ArF excimer laser exposure, a resist composition for electron beam (EB) exposure, or a resist composition for EUV exposure, particularly EB. Alternatively, it is suitable as a resist composition for EUV exposure and useful for fine processing of semiconductors.

The present invention will be described more specifically with reference to examples. In the examples, “%” and “parts” representing the content or amount used are based on mass unless otherwise specified.
The structure of the compound was confirmed by MASS (LC: Agilent 1100 type, MASS: Agilent LC / MSD type or LC / MSD TOF type).
The weight average molecular weight is a value determined by gel permeation chromatography under the following conditions.
Apparatus: HLC-8120GPC type (manufactured by Tosoh Corporation)
Column: TSKgel Multipore HXL-M x 3 + guardcolumn (manufactured by Tosoh Corporation)
Eluent: Tetrahydrofuran Flow rate: 1.0 mL / min
Detector: RI detector Column temperature: 40 ° C
Injection volume: 100 μl
Molecular weight standard: Standard polystyrene (manufactured by Tosoh Corporation)

式（Ｉ−１９−１）で表される塩２０．２０部と、クロロホルム１００部とを混合した溶液に、４−メチルモルホリン Ｎ−オキシド５０％水溶液９．１６部と四酸化オスミウム４．０％水溶液０．６４部とを加えて得られた混合物を、２３℃で２４時間攪拌した。反応混合溶液に１％シュウ酸溶液３０部を加え、クロロホルムにより抽出し、イオン交換水で洗浄した。抽出した有機層を減圧濃縮し、得られた残渣にアセトニトリル、２−メトキシ−２−メチルプロパンとｎ−ヘプタンの混合溶液を加えて攪拌した後、上澄みを除去し、残渣を乾燥することで、式（Ｉ−１９−２）で表される塩２１．９５部を得た。 Example 1 [Synthesis of a salt represented by the formula (I-19)]

In a solution obtained by mixing 20.20 parts of the salt represented by the formula (I-19-1) and 100 parts of chloroform, 9.16 parts of a 50% aqueous solution of 4-methylmorpholine N-oxide and 4.0 parts of osmium tetroxide. A mixture obtained by adding 0.64 part of a% aqueous solution was stirred at 23 ° C. for 24 hours. 30 parts of a 1% oxalic acid solution was added to the reaction mixture, extracted with chloroform, and washed with ion-exchanged water. The extracted organic layer was concentrated under reduced pressure, a mixed solution of acetonitrile, 2-methoxy-2-methylpropane and n-heptane was added to the resulting residue and stirred, and then the supernatant was removed and the residue was dried. 21.95 parts of the salt represented by the formula (I-19-2) was obtained.

式（Ｉ−１９−２）で表される塩５．１０部と、クロロホルム７２部とを混合した溶液に、Ｎ−メチルピロリジン１．１１部と式（Ｉ−１９−３）で表される化合物２．１０部とを加えて得られた混合物を、２３℃で４時間攪拌した。反応混合溶液に１％シュウ酸溶液１００部を加え、クロロホルムにより抽出し、イオン交換水で洗浄した。抽出した有機層を減圧濃縮し、得られた残渣にアセトニトリル、２−メトキシ−２−メチルプロパンとｎ−ヘプタンの混合溶液を加えて攪拌した後、上澄みを除去し、残渣を乾燥することで、式（Ｉ−１９−３）で表される塩２．８２部を得た。

式（Ｉ−１９−３）で表される塩２．３２部及びクロロホルム３０部を仕込み、２３℃で３０分間攪拌した。その後、式（Ｉ−１９−４）で表される化合物１．７０部を添加し、２３℃で５時間攪拌した。得られた反応溶液をろ過し、回収されたろ液を濃縮した。得られた濃縮物に、クロロホルム７０部及びイオン交換水２０部を加え、２３℃で３０分間攪拌した。その後、静置し、分液して有機層を得た。得られた有機層に、イオン交換水２０部を加え、２３℃で３０分間攪拌した。この水洗の操作をさらに７回行った。得られた有機層に活性炭１．００部を仕込み、２３℃で３０分間攪拌し、ろ過した。ろ液を濃縮し、得られた濃縮物に、ｔｅｒｔ−ブチルメチルエーテル２４部及びクロロホルム６部を加えて攪拌した。上澄液を除去し、上澄液除去後の残渣をさらに濃縮した。得られた濃縮物に、ｔｅｒｔ−ブチルメチルエーテル１６部、ｎ−ヘプタン１６部及びクロロホルム４部を加えて攪拌した。上澄液を除去し、上澄液除去後の残渣をさらに濃縮した。得られた濃縮物をアセトニトリルに溶解した後、濃縮することにより、式（Ｉ−１９）で表される塩１．８０部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ３０５．１
ＭＡＳＳ（ＥＳＩ（−）Ｓｐｅｃｔｒｕｍ）：Ｍ⁻ ５２７．１

In a solution obtained by mixing 5.10 parts of the salt represented by the formula (I-19-2) and 72 parts of chloroform, 1.11 parts of N-methylpyrrolidine and the formula (I-19-3) The mixture obtained by adding 2.10 parts of compound was stirred at 23 ° C. for 4 hours. 100 parts of a 1% oxalic acid solution was added to the reaction mixture, extracted with chloroform, and washed with ion-exchanged water. The extracted organic layer was concentrated under reduced pressure, a mixed solution of acetonitrile, 2-methoxy-2-methylpropane and n-heptane was added to the resulting residue and stirred, and then the supernatant was removed and the residue was dried. 2.82 parts of the salt represented by the formula (I-19-3) were obtained.

2.32 parts of the salt represented by the formula (I-19-3) and 30 parts of chloroform were charged and stirred at 23 ° C. for 30 minutes. Thereafter, 1.70 parts of a compound represented by the formula (I-19-4) was added, and the mixture was stirred at 23 ° C. for 5 hours. The obtained reaction solution was filtered, and the collected filtrate was concentrated. To the obtained concentrate, 70 parts of chloroform and 20 parts of ion-exchanged water were added and stirred at 23 ° C. for 30 minutes. Then, it left still and liquid-separated and obtained the organic layer. To the obtained organic layer, 20 parts of ion-exchanged water was added and stirred at 23 ° C. for 30 minutes. This washing operation was further performed 7 times. The obtained organic layer was charged with 1.00 parts of activated carbon, stirred at 23 ° C. for 30 minutes, and filtered. The filtrate was concentrated, and 24 parts of tert-butyl methyl ether and 6 parts of chloroform were added to the resulting concentrate and stirred. The supernatant was removed, and the residue after removing the supernatant was further concentrated. To the obtained concentrate, 16 parts of tert-butyl methyl ether, 16 parts of n-heptane and 4 parts of chloroform were added and stirred. The supernatant was removed, and the residue after removing the supernatant was further concentrated. The obtained concentrate was dissolved in acetonitrile and then concentrated to obtain 1.80 parts of the salt represented by the formula (I-19).
MASS (ESI (+) Spectrum): M ⁺ 305.1
MASS (ESI (−) Spectrum): M ^- 527.1

式（Ｉ−２０−３）で表される化合物７．１２部と、クロロホルム２８部とを混合した溶液に、１，１’−カルボニルジイミダゾール５．９５部とを加えて得られた混合物を、２３℃で３時間攪拌した。得られた反応混合溶液に、式（Ｉ−１９−２）で表される塩１４．１０部とクロロホルム５０部とを混合した溶液を加え、２３℃で１時間攪拌した。反応混合溶液に炭酸カリウム水溶液を加え、クロロホルムにより抽出した。抽出した有機層をイオン交換水で洗浄した後、減圧濃縮した。得られた残渣にアセトニトリル２−メトキシ−２−メチルプロパンとｎ−ヘプタンの混合溶液を加えて攪拌した後、上澄みを除去し、残渣を乾燥することで、式（Ｉ−２０−３）で表される塩１２．００部を得た。

式（Ｉ−２０−３）で表される塩２．３６部及びクロロホルム３０部を仕込み、２３℃で３０分間攪拌した。その後、式（Ｉ−１９−４）で表される化合物１．７０部を添加し、２３℃で５時間攪拌した。得られた反応溶液をろ過し、回収されたろ液を濃縮した。得られた濃縮物に、クロロホルム７０部及びイオン交換水２０部を加え、２３℃で３０分間攪拌した。その後、静置し、分液して有機層を得た。得られた有機層に、イオン交換水２０部を加え、２３℃で３０分間攪拌した。この水洗の操作をさらに７回行った。得られた有機層に活性炭１．００部を仕込み、２３℃で３０分間攪拌し、ろ過した。ろ液を濃縮し、得られた濃縮物に、ｔｅｒｔ−ブチルメチルエーテル２４部及びクロロホルム６部を加えて攪拌した。上澄液を除去し、上澄液除去後の残渣をさらに濃縮した。得られた濃縮物に、ｔｅｒｔ−ブチルメチルエーテル２０部、ｎ−ヘプタン１５部及びクロロホルム５部を加えて攪拌した。上澄液を除去し、上澄液除去後の残渣をさらに濃縮した。得られた濃縮物をアセトニトリルに溶解した後、濃縮することにより、式（Ｉ−２０）で表される塩１．８０部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ３０５．１
ＭＡＳＳ（ＥＳＩ（−）Ｓｐｅｃｔｒｕｍ）：Ｍ⁻ ５４１．１ Example 2: Synthesis of salt represented by formula (I-20)

A mixture obtained by adding 5.95 parts of 1,1′-carbonyldiimidazole to a solution obtained by mixing 7.12 parts of the compound represented by the formula (I-20-3) and 28 parts of chloroform is obtained. , And stirred at 23 ° C. for 3 hours. A solution obtained by mixing 14.10 parts of the salt represented by the formula (I-19-2) and 50 parts of chloroform was added to the obtained reaction mixture solution, followed by stirring at 23 ° C. for 1 hour. An aqueous potassium carbonate solution was added to the reaction mixture solution, and the mixture was extracted with chloroform. The extracted organic layer was washed with ion exchange water and then concentrated under reduced pressure. To the obtained residue, a mixed solution of acetonitrile 2-methoxy-2-methylpropane and n-heptane was added and stirred, and then the supernatant was removed, and the residue was dried, thereby being represented by the formula (I-20-3). 12.00 parts of the salt obtained.

2.36 parts of a salt represented by the formula (I-20-3) and 30 parts of chloroform were charged and stirred at 23 ° C. for 30 minutes. Thereafter, 1.70 parts of a compound represented by the formula (I-19-4) was added, and the mixture was stirred at 23 ° C. for 5 hours. The obtained reaction solution was filtered, and the collected filtrate was concentrated. To the obtained concentrate, 70 parts of chloroform and 20 parts of ion-exchanged water were added and stirred at 23 ° C. for 30 minutes. Then, it left still and liquid-separated and obtained the organic layer. To the obtained organic layer, 20 parts of ion-exchanged water was added and stirred at 23 ° C. for 30 minutes. This washing operation was further performed 7 times. The obtained organic layer was charged with 1.00 parts of activated carbon, stirred at 23 ° C. for 30 minutes, and filtered. The filtrate was concentrated, and 24 parts of tert-butyl methyl ether and 6 parts of chloroform were added to the resulting concentrate and stirred. The supernatant was removed, and the residue after removing the supernatant was further concentrated. To the resulting concentrate, 20 parts of tert-butyl methyl ether, 15 parts of n-heptane and 5 parts of chloroform were added and stirred. The supernatant was removed, and the residue after removing the supernatant was further concentrated. The obtained concentrate was dissolved in acetonitrile and then concentrated to obtain 1.80 parts of the salt represented by the formula (I-20).
MASS (ESI (+) Spectrum): M ⁺ 305.1
MASS (ESI (−) Spectrum): M ^- 541.1

式（Ｉ−７−１）で表される化合物６．００部及びクロロホルム３０部を仕込み、２３℃で３０分間攪拌した。得られた混合物に、式（Ｉ−７−２）で表される化合物５．５１部を仕込み、６０℃で１時間攪拌することにより、式（Ｉ−７−３）で表される化合物を含む溶液を得た。
得られた式（Ｉ−７−３）で表される化合物を含む溶液を２３℃まで冷却し、式（Ｉ−７−４）で表される化合物３．６７部及びクロロホルム３．６７部の混合溶液を３０分かけて滴下し、さらに２３℃で１２時間攪拌した。得られた反応マスに、イオン交換水１５部を仕込み、攪拌、分液を行った。水洗を３回行った。得られた有機層をろ過した後、回収されたろ液を濃縮することにより、式（Ｉ−７−５）で表される塩６．１２部を得た。

式（Ｉ−７−５）で表される化合物５．００部及びアセトニトリル２７．８５部を仕込み、２３℃で３０分間攪拌した。得られた混合物を０℃まで冷却し、水素化ホウ素ナトリウム０．３１部及びイオン交換水３．０７部の混合溶液を１０分かけて滴下し、更に、０℃で２時間攪拌した。得られた反応溶液に、１Ｎ塩酸８．１１部を仕込み、２３℃で３０分間攪拌した後、濃縮した。得られた濃縮マスに、クロロホルム４４．５６部及びイオン交換水１１．１４部を仕込み、攪拌、分液を行った。水洗を３回行った。得られた有機層をろ過した後、回収されたろ液を濃縮し、得られた濃縮マスに、Ｎ−ヘプタン３７．７０部を加えて攪拌し、上澄液を除去した。得られた残渣をクロロホルムに溶解し、濃縮することにより、式（Ｉ−７-６）で表される化合物３．２７部を得た。

式（Ｉ−７−７）で表される塩を、特開２００８−１２７３６７号公報に記載された方法で合成した。
式（Ｉ−７−７）で表される塩３．８７部及びアセトニトリル１９．４１部を仕込み、３０℃で３０分間攪拌した。得られた混合物に、式（Ｉ−７−２）で表される化合物１．７１部を仕込み、８０℃で１時間攪拌することにより、式（Ｉ−７−８）で表される化合物を含む溶液を得た。

得られた式（Ｉ−７−８）で表される化合物を含む溶液を２３℃まで冷却し、式（Ｉ−７−６）で表される化合物３．２７部及びアセトニトリル３．２７部の混合溶液を仕込み、８０℃で１２時間攪拌した。得られた反応マスを濃縮した後、得られた濃縮マスに、クロロホルム３８．８２部及びイオン交換水９．７０部を仕込み、攪拌、分液を行った。水洗を５回行った。得られた有機層に活性炭１．００部を仕込み、２３℃で３０分間攪拌し、ろ過した。ろ液を濃縮し、得られた濃縮物に、ｔｅｒｔ−ブチルメチルエーテル３７．９０部を加えて攪拌し、上澄液を除去した。得られた残渣をアセトニトリルに溶解し、濃縮した。その後、得られた濃縮物に、アセトニトリル１．８４部及びｔｅｒｔ−ブチルメチルエーテル２７．６０部を加えて攪拌し、上澄液を除去した。得られた残渣をクロロホルムに溶解し、濃縮することにより、式（Ｉ−７−９）で表される塩２．９６部を得た。

式（Ｉ−７−９）で表される塩２．９６部及びアセトニトリル１６．８０部を仕込み、２３℃で３０分間攪拌した。得られた混合物にシュウ酸０．１０部及びイオン交換水０．５１部の混合溶液を添加し、８０℃で１０時間攪拌した後、濃縮した。得られた濃縮マスに、クロロホルム４０．３２部、イオン交換水１０．０８部及び２８％アンモニア水０．３部を仕込み、攪拌、分液を行った。得られた有機層に、アセトニトリル３．３６部及びイオン交換水１０．０８部を仕込み、攪拌、分液を行った。水洗を２回行った。得られた有機層をろ過した後、回収されたろ液を濃縮し、得られた濃縮マスに、ｔｅｒｔ−ブチルメチルエーテル１６．７５部を加えて攪拌し、上澄液を除去した。得られた残渣をクロロホルムに溶解し、濃縮することにより、式（Ｉ−７−１０）で表される化合物１．０９部を得た。 Example 3: Synthesis of a salt represented by the formula (I-7)

6.00 parts of a compound represented by the formula (I-7-1) and 30 parts of chloroform were charged and stirred at 23 ° C. for 30 minutes. The obtained mixture was charged with 5.51 parts of the compound represented by the formula (I-7-2) and stirred at 60 ° C. for 1 hour to obtain the compound represented by the formula (I-7-3). A solution containing was obtained.
The obtained solution containing the compound represented by the formula (I-7-3) was cooled to 23 ° C., and 3.67 parts of the compound represented by the formula (I-7-4) and 3.67 parts of chloroform were mixed. The mixed solution was added dropwise over 30 minutes, and the mixture was further stirred at 23 ° C. for 12 hours. To the obtained reaction mass, 15 parts of ion-exchanged water was charged, stirred and separated. Water washing was performed 3 times. The obtained organic layer was filtered, and then the collected filtrate was concentrated to obtain 6.12 parts of the salt represented by the formula (I-7-5).

5.00 parts of a compound represented by the formula (I-7-5) and 27.85 parts of acetonitrile were charged and stirred at 23 ° C. for 30 minutes. The obtained mixture was cooled to 0 ° C., a mixed solution of 0.31 part of sodium borohydride and 3.07 parts of ion-exchanged water was added dropwise over 10 minutes, and the mixture was further stirred at 0 ° C. for 2 hours. To the obtained reaction solution, 8.11 parts of 1N hydrochloric acid was added, stirred at 23 ° C. for 30 minutes, and concentrated. The obtained concentrated mass was charged with 44.56 parts of chloroform and 11.14 parts of ion-exchanged water, and stirred and separated. Water washing was performed 3 times. After filtering the obtained organic layer, the collected filtrate was concentrated, 37.70 parts of N-heptane was added to the resulting concentrated mass and stirred, and the supernatant was removed. The obtained residue was dissolved in chloroform and concentrated to obtain 3.27 parts of a compound represented by the formula (I-7-6).

A salt represented by the formula (I-7-7) was synthesized by the method described in JP-A-2008-127367.
3.87 parts of the salt represented by the formula (I-7-7) and 19.41 parts of acetonitrile were charged and stirred at 30 ° C. for 30 minutes. The obtained mixture was charged with 1.71 parts of the compound represented by the formula (I-7-2), and stirred at 80 ° C. for 1 hour to obtain the compound represented by the formula (I-7-8). A solution containing was obtained.

The obtained solution containing the compound represented by the formula (I-7-8) was cooled to 23 ° C., and 3.27 parts of the compound represented by the formula (I-7-6) and 3.27 parts of acetonitrile were cooled. The mixed solution was charged and stirred at 80 ° C. for 12 hours. After concentrating the obtained reaction mass, 38.82 parts of chloroform and 9.70 parts of ion-exchanged water were added to the obtained concentrated mass, followed by stirring and liquid separation. Water washing was performed 5 times. The obtained organic layer was charged with 1.00 parts of activated carbon, stirred at 23 ° C. for 30 minutes, and filtered. The filtrate was concentrated, and 37.90 parts of tert-butyl methyl ether was added to the resulting concentrate and stirred, and the supernatant was removed. The resulting residue was dissolved in acetonitrile and concentrated. Thereafter, 1.84 parts of acetonitrile and 27.60 parts of tert-butyl methyl ether were added to the obtained concentrate and stirred, and the supernatant was removed. The obtained residue was dissolved in chloroform and concentrated to obtain 2.96 parts of the salt represented by the formula (I-7-9).

2.96 parts of the salt represented by the formula (I-7-9) and 16.80 parts of acetonitrile were charged and stirred at 23 ° C. for 30 minutes. A mixed solution of 0.10 parts of oxalic acid and 0.51 part of ion-exchanged water was added to the obtained mixture, and the mixture was stirred at 80 ° C. for 10 hours and then concentrated. To the obtained concentrated mass, 40.32 parts of chloroform, 10.08 parts of ion-exchanged water and 0.3 part of 28% ammonia water were added, and the mixture was stirred and separated. To the obtained organic layer, 3.36 parts of acetonitrile and 10.08 parts of ion-exchanged water were added, and the mixture was stirred and separated. Washing with water was performed twice. The obtained organic layer was filtered, and then the collected filtrate was concentrated. To the resulting concentrated mass, 16.75 parts of tert-butyl methyl ether was added and stirred, and the supernatant was removed. The obtained residue was dissolved in chloroform and concentrated to obtain 1.09 parts of a compound represented by the formula (I-7-10).

式（Ｉ−７−１１）で表される化合物０．２８部及びクロロホルム１０部を混合した溶液に、１，１’−カルボニルジイミダゾール０．２４部を加えた。得られた混合物を、２３℃で３時間攪拌した。得られた反応溶液に、式（Ｉ−７−１０）で表される塩１．００部及びクロロホルム１０．００部を混合した溶液を加え、２３℃で１時間攪拌した。反応混合溶液に炭酸カリウム水溶液を加え、クロロホルムにより抽出した。抽出した有機層をイオン交換水で洗浄した後、濃縮した。得られた残渣をアセトニトリルに溶解し、濃縮した。
その後、得られた濃縮物に、ｔｅｒｔ−ブチルメチルエーテル６．２５部を加えて攪拌し、上澄液を除去した。得られた残渣をクロロホルムに溶解し、濃縮することにより、式（Ｉ−７−１２）で表される塩０．７８部を得た。

式（Ｉ−７−１２）で表される塩０．６８部及びクロロホルム１０部を仕込み、２３℃で３０分間攪拌した。得られた混合物に、式（Ｉ−７−２）で表される化合物０．４３部を添加し、２３℃で５時間攪拌した。得られた反応溶液をろ過し、回収されたろ液を濃縮した。得られた濃縮物に、クロロホルム７０部及びイオン交換水２０部を加え、２３℃で３０分間攪拌した。その後、静置し、分液して有機層を得た。得られた有機層に、イオン交換水２０部を加え、２３℃で３０分間攪拌した。この水洗の操作をさらに５回行った。得られた有機層に活性炭０．３０部を仕込み、２３℃で３０分間攪拌し、ろ過した。ろ液を濃縮し、得られた濃縮物に、ｔｅｒｔ−ブチルメチルエーテル１０部を加えて攪拌した。上澄液を除去し、上澄液除去後の残渣をさらに濃縮することにより、式（Ｉ−７）で表される塩０．７０部を得た。

To a solution obtained by mixing 0.28 part of the compound represented by the formula (I-7-11) and 10 parts of chloroform, 0.24 part of 1,1′-carbonyldiimidazole was added. The resulting mixture was stirred at 23 ° C. for 3 hours. A solution obtained by mixing 1.00 parts of the salt represented by the formula (I-7-10) and 10.00 parts of chloroform was added to the obtained reaction solution, and the mixture was stirred at 23 ° C. for 1 hour. An aqueous potassium carbonate solution was added to the reaction mixture solution, and the mixture was extracted with chloroform. The extracted organic layer was washed with ion exchange water and then concentrated. The resulting residue was dissolved in acetonitrile and concentrated.
Thereafter, 6.25 parts of tert-butyl methyl ether was added to the obtained concentrate and stirred, and the supernatant was removed. The obtained residue was dissolved in chloroform and concentrated to obtain 0.78 parts of the salt represented by the formula (I-7-12).

0.68 part of the salt represented by the formula (I-7-12) and 10 parts of chloroform were charged and stirred at 23 ° C. for 30 minutes. To the obtained mixture, 0.43 part of a compound represented by the formula (I-7-2) was added, and the mixture was stirred at 23 ° C. for 5 hours. The obtained reaction solution was filtered, and the collected filtrate was concentrated. To the obtained concentrate, 70 parts of chloroform and 20 parts of ion-exchanged water were added and stirred at 23 ° C. for 30 minutes. Then, it left still and liquid-separated and obtained the organic layer. To the obtained organic layer, 20 parts of ion-exchanged water was added and stirred at 23 ° C. for 30 minutes. This washing operation was further performed 5 times. The obtained organic layer was charged with 0.30 part of activated carbon, stirred at 23 ° C. for 30 minutes, and filtered. The filtrate was concentrated, and 10 parts of tert-butyl methyl ether was added to the resulting concentrate and stirred. The supernatant was removed, and the residue after removing the supernatant was further concentrated to obtain 0.70 parts of the salt represented by the formula (I-7).

MASS (ESI (+) Spectrum): M ⁺ 263.1
MASS (ESI (−) Spectrum): M ^- 699.2

式（Ｉ−７−１０）で表される塩１．００部及びクロロホルム１０．００部を仕込み、２３℃で３０分間攪拌した後、ピリジン０．１４部を仕込み、４０℃に昇温した。得られた混合物に、式（Ｉ−１６−１）で表される化合物０．３７部及びクロロホルム５部の混合溶液を１時間かけて滴下した。滴下後、４０℃で８時間攪拌し、２３℃に温度を下げた。得られた反応溶液に、イオン交換水１０部を添加、攪拌し、分液により有機層を回収した。回収された有機層に、５℃の１０％炭酸カリウム水溶液１０部を添加して洗浄し、分液して有機層を回収した後、回収された有機層にさらに、イオン交換水１０部を添加して水洗し、分液を行って有機層を回収した。この水洗操作を３回繰り返して行った。回収された有機層を濃縮した後、得られた残渣をアセトニトリルに溶解し、濃縮した。その後、得られた濃縮物に、ｔｅｒｔ−ブチルメチルエーテル５部を加えて攪拌し、上澄液を除去した。得られた残渣をクロロホルムに溶解し、濃縮することにより、式（Ｉ−１６−２）で表される塩０．３８部を得た。

式（Ｉ−１６−２）で表される塩０．３６部及びクロロホルム５部を仕込み、２３℃で３０分間攪拌した。得られた混合物に、式（Ｉ−１６−３）で表される化合物０．２２部を添加し、２３℃で５時間攪拌した。得られた反応溶液をろ過し、回収されたろ液を濃縮した。得られた濃縮物に、クロロホルム２０部及びイオン交換水１０部を加え、２３℃で３０分間攪拌した。その後、静置し、分液して有機層を得た。得られた有機層に、イオン交換水１０部を加え、２３℃で３０分間攪拌した。この水洗の操作をさらに５回行った。得られた有機層に活性炭０．１０部を仕込み、２３℃で３０分間攪拌し、ろ過した。ろ液を濃縮し、得られた濃縮物に、ｔｅｒｔ−ブチルメチルエーテル５部を加えて攪拌した。上澄液を除去し、上澄液除去後の残渣をさらに濃縮することにより、式（Ｉ−１６）で表される塩０．３３部を得た。 Example 4: Synthesis of salt represented by formula (I-16)

After adding 1.00 part of salt represented by the formula (I-7-10) and 10.00 part of chloroform and stirring at 23 ° C. for 30 minutes, 0.14 part of pyridine was added and heated to 40 ° C. To the obtained mixture, a mixed solution of 0.37 part of the compound represented by the formula (I-16-1) and 5 parts of chloroform was added dropwise over 1 hour. After dropping, the mixture was stirred at 40 ° C. for 8 hours, and the temperature was lowered to 23 ° C. To the obtained reaction solution, 10 parts of ion exchange water was added and stirred, and the organic layer was recovered by liquid separation. 10 parts of 10% aqueous potassium carbonate solution at 5 ° C. is added to the collected organic layer for washing, liquid separation is performed to collect the organic layer, and then 10 parts of ion exchange water is further added to the collected organic layer The organic layer was recovered by washing with water and liquid separation. This washing operation was repeated 3 times. After the collected organic layer was concentrated, the obtained residue was dissolved in acetonitrile and concentrated. Thereafter, 5 parts of tert-butyl methyl ether was added to the resulting concentrate and stirred, and the supernatant was removed. The obtained residue was dissolved in chloroform and concentrated to obtain 0.38 parts of the salt represented by the formula (I-16-2).

0.36 part of the salt represented by the formula (I-16-2) and 5 parts of chloroform were charged and stirred at 23 ° C. for 30 minutes. To the obtained mixture, 0.22 part of a compound represented by the formula (I-16-3) was added, and the mixture was stirred at 23 ° C. for 5 hours. The obtained reaction solution was filtered, and the collected filtrate was concentrated. To the obtained concentrate, 20 parts of chloroform and 10 parts of ion-exchanged water were added and stirred at 23 ° C. for 30 minutes. Then, it left still and liquid-separated and obtained the organic layer. To the obtained organic layer, 10 parts of ion-exchanged water was added and stirred at 23 ° C. for 30 minutes. This washing operation was further performed 5 times. The obtained organic layer was charged with 0.10 parts of activated carbon, stirred at 23 ° C. for 30 minutes, and filtered. The filtrate was concentrated, and 5 parts of tert-butyl methyl ether was added to the resulting concentrate and stirred. The supernatant was removed, and the residue after removing the supernatant was further concentrated to obtain 0.33 parts of the salt represented by the formula (I-16).

MASS (ESI (+) Spectrum): M ⁺ 263.1
MASS (ESI (−) Spectrum): M ^- 741.3

Synthesis of Resin (A) The compound (monomer) used for the synthesis of resin (A) is shown below. Hereinafter, it is referred to as “monomer (a1-1-3)” or the like according to the formula number of the compound.

Synthesis Example 1 [Synthesis of Resin A1]
The monomer (a1-1-3), monomer (a1-2-7), monomer (a2-1-1), monomer (a3-2-3) and monomer (a3-1-1) are mixed in a molar ratio [ Monomer (a1-1-3): monomer (a1-2-8): monomer (a2-1-1): monomer (a3-2-3): monomer (a3-1-1)] is 28:15 : 5: 20: 32 The mixture was further mixed with propylene glycol monomethyl ether acetate 1.5 times by mass with respect to the total mass of all monomers. Into the obtained mixture, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were respectively added to 1.00 mol% and 3.00 mol% with respect to the total number of moles of all monomers. It added so that it might become. This was polymerized by heating at 75 ° C. for about 5 hours. Thereafter, the polymerization reaction solution was poured into a large amount of a mixed solvent of methanol and water (mass ratio methanol: water = 4: 1) to precipitate the resin. This resin was filtered and collected. Once again dissolved in propylene glycol monomethyl ether acetate, poured into a mixed solvent of a large amount of methanol and water to precipitate the resin, and then filtered and recovered the precipitated resin twice to perform reprecipitation and purification. A copolymer having an average molecular weight of 7.5 × 10 ³ was obtained with a yield of 63%. This copolymer has the following structural units, and is designated as resin A1.

(Preparation of resist composition)
Each of the following components was mixed in parts by mass shown in Table 5 and dissolved in a solvent, and then filtered through a fluororesin filter having a pore size of 0.2 μm to prepare a resist composition.

<Resin (A)>
A1: Resin A1

ＢＸ：式（ＢＸ）で表される塩；特開２０１２−７２１０９号公報記載の方法で合成

＜塩基性化合物（Ｃ）：クエンチャー＞
Ｃ１：テトラ−ｎ−ブチルアンモニウムサリチラート（東京化成工業（株）製）
＜溶剤＞
プロピレングリコールモノメチルエーテルアセテート ４００部
プロピレングリコールモノメチルエーテル １５０部
γ−ブチロラクトン ５部 <Salt (I)>
I-19: salt represented by formula (I-19) I-20: salt represented by formula (I-20) I-7: salt represented by formula (I-7) I-16: formula Salt represented by (I-16) <Acid generator (B)>
B1-21: a salt represented by the formula (B1-21); synthesized by the method described in JP2011-126869A

BX: salt represented by the formula (BX); synthesized by the method described in JP2012-72109A

<Basic compound (C): quencher>
C1: Tetra-n-butylammonium salicylate (Tokyo Chemical Industry Co., Ltd.)
<Solvent>
Propylene glycol monomethyl ether acetate 400 parts Propylene glycol monomethyl ether 150 parts γ-butyrolactone 5 parts

Examples 11 to 16 and Comparative Example 1
(Electron beam exposure evaluation of resist composition)
A 6-inch silicon wafer was treated on a direct hot plate with hexamethyldisilazane at 90 ° C. for 60 seconds. This silicon wafer was spin-coated with a resist composition so that the film thickness of the composition layer was 0.04 μm. Thereafter, the composition layer was formed by pre-baking on a direct hot plate at a temperature shown in the “PB” column of Table 5 for 60 seconds. A line-and-space pattern was directly drawn on the composition layer formed on the wafer using an electron beam drawing machine ("HL-800D 50 keV" manufactured by Hitachi, Ltd.) while changing the exposure stepwise. .
After exposure, post exposure baking is performed for 60 seconds on the hot plate at the temperature shown in the “PEB” column of Table 5, and then paddle development is performed for 60 seconds with an aqueous 2.38 mass% tetramethylammonium hydroxide solution. A resist pattern was obtained.
The obtained resist pattern (line and space pattern) was observed with a scanning electron microscope, and the exposure amount at which the line width and space width of the 60 nm line and space pattern were 1: 1 was defined as effective sensitivity.

<Pattern collapse evaluation>
Pattern collapse evaluation (PCM): In the case of a 60 nm line and space pattern, when the exposure amount is increased, even if the line width becomes thinner than 55 nm, the pattern disappearance due to the collapse or peeling is not observed. Then, the case where pattern disappearance due to falling or peeling was observed was taken as x.
The results are shown in Table 6. The numbers in parentheses indicate the minimum line width (nm) of the resist pattern in which pattern disappearance due to collapse or peeling was not observed.

Examples 17 and 18
(EUV exposure evaluation of resist composition)
An 8-inch silicon wafer was treated with hexamethyldisilazane at 90 ° C. for 60 seconds on a direct hot plate. This silicon wafer was spin-coated with a resist composition so that the film thickness of the composition layer was 0.035 μm.
Thereafter, the composition layer was formed by pre-baking on a direct hot plate at a temperature shown in the “PB” column of Table 5 for 60 seconds. The composition layer formed on the wafer was exposed to a line and space pattern using an EUV exposure machine while changing the exposure amount stepwise.
After exposure, post exposure baking is performed for 60 seconds on the hot plate at the temperature shown in the “PEB” column of Table 5, and then paddle development is performed for 60 seconds with an aqueous 2.38 mass% tetramethylammonium hydroxide solution. A resist pattern was obtained.
The obtained resist pattern (line and space pattern) was observed with a scanning electron microscope, and the exposure amount at which the line width and space width of the line and space pattern having a line width of 40 nm were 1: 1 was defined as effective sensitivity.

<Pattern collapse evaluation>
Pattern collapse evaluation (PCM): In the case of a 40 nm line and space pattern, when the exposure amount is increased, even if the line width becomes thinner than 30 nm, the pattern disappearance due to the collapse or peeling is not observed. Then, the case where pattern disappearance due to falling or peeling was observed was taken as x.
The results are shown in Table 7. The numbers in parentheses indicate the minimum line width (nm) of the resist pattern in which pattern disappearance due to collapse or peeling was not observed.

  Since the resist composition of the present invention is excellent in resistance to pattern collapse at the time of producing a resist pattern, it is suitable for fine processing of semiconductors and is extremely useful industrially.

Claims (6)

A salt represented by the formula (I).

[In the formula (I),
Q ¹ and Q ² each independently represents a fluorine atom or a C 1-6 perfluoroalkyl group.
L ¹ represents a carbonyl group or —CF ₂ —.
X ⁰ represents a single bond, a divalent saturated hydrocarbon group having 1 to 14 carbon atoms which may have a substituent, or a group represented by the formula (a-1).

(In the formula (a-1),
c represents 0 or 1;
X ¹⁰ and X ¹¹ each independently represent an oxygen atom, a carbonyl group, a carbonyloxy group or an oxycarbonyl group.
A ¹⁰ , A ¹¹ and A ¹² each independently represent a C 1-12 divalent saturated hydrocarbon group which may have a substituent.
* A bond with a carbon atom. )
X ¹ represents — (CH ₂ ) _a —O— (CH ₂ ) _b — ^{* 1} , — (CH ₂ ) _a —O—CO— ^{* 1} , — (CH ₂ ) _a —O—CH ₂ —CO—. ^{O-* 1} or - represents a ^{_{* 1 - (CH 2) a}} -NR 2 - (CH 2) b. * 1 represents a bond with W ¹ .
a represents an integer of 0 to 6.
b represents 0 or 1.
R ² represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
W ¹ represents a monovalent alicyclic hydrocarbon group having 3 to 36 carbon atoms, and the methylene group constituting the alicyclic hydrocarbon group is replaced with an oxygen atom, a sulfur atom, a carbonyl group or a sulfonyl group. The hydrogen atom contained in the alicyclic hydrocarbon group may be a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or a monovalent alicyclic ring having 3 to 18 carbon atoms. It may be substituted with a formula hydrocarbon group or a monovalent aromatic hydrocarbon group having 6 to 14 carbon atoms.
Z ⁺ represents an organic cation. ] The salt according to claim 1, wherein W ^{1 in the} formula (I) is a 2-oxoadamantyl group, an adamantyl group optionally having an alkyl group having 1 to 12 carbon atoms or a hydroxy group.   The acid generator containing the salt of Claim 1 or 2. Furthermore, the acid generator of Claim 3 containing acid generators other than the salt of Claim 1 or 2. A resist composition comprising the acid generator according to claim 3 or 4 and a resin having an acid labile group. (1) The process of apply | coating the resist composition of Claim 5 on a board | substrate,
(2) The process of drying the composition after application | coating and forming a composition layer,
(3) a step of exposing the composition layer;
(4) a step of heating the composition layer after exposure, and (5) a step of developing the composition layer after heating,
A method for producing a resist pattern including: