JP2017057193A - Salt, acid generator, resist composition and production method of resist pattern - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a salt, an acid generator, a resist composition and the like, from which a resist pattern can be produced with a good focus margin.SOLUTION: The salt is represented by formula (I); and the acid generator and the resist composition comprise the salt. In the formula, Rand Reach independently represent a hydrogen atom, a hydroxy group or a hydrocarbon group; m and n each independently represent 1 or 2; Ar represents an aromatic hydrocarbon group or a hetero aromatic hydrocarbon group which may have a substituent; Arepresents a (1+s)-valent aliphatic saturated hydrocarbon group which may be substituted with a hydroxy group; Rrepresents an alicyclic hydrocarbon group which may be substituted with a hydroxy group, in which two hydrogen atoms included in the alicyclic hydrocarbon group may be each replaced by an oxygen atom and the two oxygen atoms may be integrated together with an alkanediyl group to form a ketal ring which may include a fluorine atom; and s represents an integer of 1 to 3.SELECTED DRAWING: None

Description

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

特許文献２には、下記式で表される塩を酸発生剤として含有するレジスト組成物が記載されている。

Patent Document 1 describes a resist composition containing a salt represented by the following formula as an acid generator.

Patent Document 2 describes a resist composition containing a salt represented by the following formula as an acid generator.

JP 2013-33161 A JP 2012-224611 A

  A resist pattern formed from the above resist composition may not always be satisfactory in terms of focus margin (DOF).

［式（Ｉ）中、
Ｒ^１及びＲ^２は、それぞれ独立に、水素原子、ヒドロキシ基又は炭素数１〜１２の炭化水素基を表し、該炭化水素基に含まれる−ＣＨ_２−は、−Ｏ−又は−ＣＯ−で置き換わっていてもよい。
ｍ及びｎは、それぞれ独立に、１又は２を表す。ｍが２のとき、２つのＲ^１は同一又は相異なり、ｎが２のとき、２つのＲ^２は同一又は相異なる。
Ａｒは、置換基を有していてもよい炭素数６〜３６の芳香族炭化水素基又は置換基を有していてもよい炭素数５〜３６のヘテロ芳香族炭化水素基を表す。
Ａ^１は、ヒドロキシ基を有していてもよい炭素数１〜１８の（１＋ｓ）価の脂肪族飽和炭化水素基を表し、該脂肪族飽和炭化水素基に含まれる−ＣＨ_２−は−Ｏ―又は−ＣＯ−で置き換わっていてもよい。
Ｒ^３は、炭素数５〜１８の脂環式炭化水素基を表し、該脂環式炭化水素基に含まれる水素原子は、ヒドロキシ基に置換されてもよく、又は該脂環式炭化水素基に含まれる水素原子２つがそれぞれ酸素原子に置換され、当該２つの酸素原子が炭素数１〜８のアルカンジイル基と一緒になってケタール環を形成してもよく、該ケタール環はフッ素原子を有していてもよく、該脂環式炭化水素基に含まれるーＣＨ_２−基は、−Ｏ−又は−ＣＯ−で置き換わっていてもよい。
ｓは、１〜３の整数を表す。］
［２］Ｒ^３が、アダマンチル基であり、該アダマンチル基に含まれる水素原子はヒドロキシ基で置換されてもよく、又は該アダマンチル基に含まれる水素原子２つがそれぞれ酸素原子に置換され、当該２つの酸素原子が炭素数１〜８のアルカンジイル基と一緒になってフッ素原子を含んでもよいケタール環を形成してもよく、該アダマンチル基に含まれるメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい［１］記載の塩。
［３］Ａｒが、置換基を有していてもよいフェニル基である［１］又は［２］記載の塩。
［４］Ａ^１が、炭素数２〜５の（１＋ｓ）価の脂肪族飽和炭化水素基である［１］〜［３］のいずれかに記載の塩。
［５］［１］〜［４］のいずれかに記載の塩を含有する酸発生剤。
［６］［５］記載の酸発生剤と酸不安定基を有する構造単位を含む樹脂とを含有するレジスト組成物。
［７］酸発生剤から発生する酸よりも酸性度の弱い塩を含有する［６］に記載のレジスト組成物。
［８］さらに、フッ素原子を有する構造単位を含む樹脂を含有する［６］又は［７］記載のレジスト組成物。
［９］（１）［６］〜［８］のいずれかに記載のレジスト組成物を基板上に塗布する工程、
（２）塗布後の組成物を乾燥させて組成物層を形成する工程、
（３）組成物層に露光する工程、
（４）露光後の組成物層を加熱する工程、及び
（５）加熱後の組成物層を現像する工程、を含むレジストパターンの製造方法。 The present invention includes the following inventions.
[1] A salt represented by the formula (I).

[In the formula (I),
R ¹ and R ² each independently represent a hydrogen atom, a hydroxy group or a hydrocarbon group having 1 to 12 carbon atoms, and —CH ₂ — contained in the hydrocarbon group is —O— or —CO—. It may be replaced.
m and n each independently represents 1 or 2. When m is 2, two R ¹ are the same or different, and when n is 2, two R ² are the same or different.
Ar represents an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent or a heteroaromatic hydrocarbon group having 5 to 36 carbon atoms which may have a substituent.
A ¹ represents a (1 + s) -valent aliphatic saturated hydrocarbon group having 1 to 18 carbon atoms that may have a hydroxy group, and —CH ₂ — contained in the aliphatic saturated hydrocarbon group is —O -Or -CO- may be substituted.
R ³ represents an alicyclic hydrocarbon group having 5 to 18 carbon atoms, and a hydrogen atom contained in the alicyclic hydrocarbon group may be substituted with a hydroxy group, or the alicyclic hydrocarbon group May be substituted with oxygen atoms, and the two oxygen atoms may form a ketal ring together with an alkanediyl group having 1 to 8 carbon atoms, and the ketal ring may contain a fluorine atom. The —CH ₂ — group contained in the alicyclic hydrocarbon group may be replaced by —O— or —CO—.
s represents an integer of 1 to 3. ]
[2] R ³ is an adamantyl group, and a hydrogen atom contained in the adamantyl group may be substituted with a hydroxy group, or two hydrogen atoms contained in the adamantyl group are each substituted with an oxygen atom, Two oxygen atoms may form a ketal ring which may contain a fluorine atom together with an alkanediyl group having 1 to 8 carbon atoms, and the methylene group contained in the adamantyl group is replaced by an oxygen atom or a carbonyl group. The salt described in [1].
[3] The salt according to [1] or [2], wherein Ar is a phenyl group which may have a substituent.
[4] The salt according to any one of [1] to [3], wherein A ¹ is a (1 + s) -valent aliphatic saturated hydrocarbon group having 2 to 5 carbon atoms.
[5] An acid generator containing the salt according to any one of [1] to [4].
[6] A resist composition comprising the acid generator according to [5] and a resin containing a structural unit having an acid labile group.
[7] The resist composition according to [6], which contains a salt having a lower acidity than the acid generated from the acid generator.
[8] The resist composition according to [6] or [7], further comprising a resin containing a structural unit having a fluorine atom.
[9] (1) A step of applying the resist composition according to any one of [6] to [8] 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.

  According to the resist composition of the present invention, a resist pattern having a good focus margin (DOF) can be produced.

In the present specification, “(meth) acrylate” means “at least one of acrylate and methacrylate”. The notations such as “(meth) acrylic acid” and “(meth) acryloyl” have the same meaning.
In addition, unless otherwise specified, groups such as “aliphatic hydrocarbon group” that can be linear, branched, or cyclic include both. When stereoisomers exist, all stereoisomers are included.
In the present specification, the “solid content of the resist composition” means the total of components excluding the solvent (E) described later from the total amount of the resist composition.

［式（Ｉ）中、
Ｒ^１及びＲ^２は、それぞれ独立に、水素原子、ヒドロキシ基又は炭素数１〜１２の炭化水素基を表し、該炭化水素基に含まれる−ＣＨ_２−は、−Ｏ−又は−ＣＯ−で置き換わっていてもよい。
ｍ及びｎは、それぞれ独立に、１又は２を表す。ｍが２のとき、２つのＲ^１は同一又は相異なり、ｎが２のとき、２つのＲ^２は同一又は相異なる。
Ａｒは、置換基を有していてもよい炭素数６〜３６の芳香族炭化水素基又は置換基を有していてもよい炭素数５〜３６のヘテロ芳香族炭化水素基を表す。
Ａ^１は、ヒドロキシ基を有していてもよい炭素数１〜１８の（１＋ｓ）価の脂肪族飽和炭化水素基を表し、該脂肪族飽和炭化水素基に含まれる−ＣＨ_２−は−Ｏ−又は−ＣＯ−で置き換わっていてもよい。
Ｒ^３は、炭素数５〜１８の脂環式炭化水素基を表し、該脂環式炭化水素基に含まれる水素原子は、ヒドロキシ基に置換されてもよく、又は該脂環式炭化水素基に含まれる水素原子２つがそれぞれ酸素原子に置換され、当該２つの酸素原子が炭素数１〜８のアルカンジイル基と一緒になってケタール環を形成してもよく、該ケタール環はフッ素原子を有していてもよく、該脂環式炭化水素基に含まれる−ＣＨ_２−基は、−Ｏ−又は−ＣＯ−で置き換わっていてもよい。
ｓは、１〜３の整数を表す。］ <Salt (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),
R ¹ and R ² each independently represent a hydrogen atom, a hydroxy group or a hydrocarbon group having 1 to 12 carbon atoms, and —CH ₂ — contained in the hydrocarbon group is —O— or —CO—. It may be replaced.
m and n each independently represents 1 or 2. When m is 2, two R ¹ are the same or different, and when n is 2, two R ² are the same or different.
Ar represents an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent or a heteroaromatic hydrocarbon group having 5 to 36 carbon atoms which may have a substituent.
A ¹ represents a (1 + s) -valent aliphatic saturated hydrocarbon group having 1 to 18 carbon atoms that may have a hydroxy group, and —CH ₂ — contained in the aliphatic saturated hydrocarbon group is —O -Or -CO- may be substituted.
R ³ represents an alicyclic hydrocarbon group having 5 to 18 carbon atoms, and a hydrogen atom contained in the alicyclic hydrocarbon group may be substituted with a hydroxy group, or the alicyclic hydrocarbon group May be substituted with oxygen atoms, and the two oxygen atoms may form a ketal ring together with an alkanediyl group having 1 to 8 carbon atoms, and the ketal ring may contain a fluorine atom. The —CH ₂ — group contained in the alicyclic hydrocarbon group may be replaced by —O— or —CO—.
s represents an integer of 1 to 3. ]

  In the following description, in the salt (I), the negatively charged side may be referred to as “anion (I)” and the positively charged side may be referred to as “cation (I)”.

Examples of the hydrocarbon group for R ¹ and R ² include an alkyl group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and a group formed by combining these.
As the alkyl group, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, heptyl group, 2-ethylhexyl group, octyl group , Nonyl group, decyl group, undecyl group, dodecyl group and the like.
The alicyclic hydrocarbon group may be either monocyclic or polycyclic, and the monocyclic alicyclic hydrocarbon group includes a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a methylcyclohexyl group. And cycloalkyl groups such as dimethylcyclohexyl group, cycloheptyl group, cyclooctyl 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, norbornyl group, Examples thereof include a methylnorbornyl group and an isobornyl group.
Examples of the aromatic hydrocarbon group include a phenyl group and a naphthyl group.
Examples of the group formed by combining these include an aralkyl group (benzyl group, phenethyl group, etc.), an alkyl-aryl group, a cyclohexyl-aryl group, and an aryl-cyclohexyl group.
Examples of the group in which —CH ₂ — contained in the hydrocarbon group is replaced by —O— or —CO— include a methoxy group, an ethoxy group, a butoxy group, an acetyl group, a methoxycarbonyl group, an acetyloxy group, and a butoxycarbonyloxy group. And benzoyloxy group.

m is preferably 2.
n is preferably 2.
Of m and n, at least one is preferably 2, and both m and n are more preferably 2.
R ¹ is preferably a hydrogen source.
R ² is preferably a hydrogen atom.
At least one of R ¹ and R ² is preferably a hydrogen atom, and more preferably a hydrogen atom.

Examples of the aromatic hydrocarbon group of Ar include aryl groups having 6 to 36 carbon atoms such as a phenyl group, a naphthyl group, an anthryl group, a phenanthonyl group, a biphenyl group, a triphenyl group, an indenyl group, a tetrahydronaphthyl group, and a phenanthryl group. It is done.
A hetero atom includes a nitrogen atom, an oxygen atom, and a sulfur atom.
Examples of the heteroaromatic hydrocarbon group include a furyl group and a thiophenyl group.

The aromatic hydrocarbon group preferably has 6 to 24 carbon atoms, and more preferably 6 to 18 carbon atoms.
The heteroaromatic hydrocarbon group preferably has 5 to 24 carbon atoms, and more preferably 5 to 18 carbon atoms.

Examples of the substituent that Ar may have include a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, and 2 carbon atoms. to 18 alkylcarbonyloxy group, and an alkoxycarbonyl group arylcarbonyloxy group or a C2-18 having 7 to 18 carbon atoms, -CH ₂ contained in an alkoxy group having 1 to 18 carbon atoms - are It may be replaced by -O-. A hydroxy group is preferable.
Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an n-hexyl group, and an n-heptyl group. , 2-ethylhexyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, etc. Among them, an alkyl group having 1 to 6 carbon atoms is preferable, and methyl Group, ethyl group, n-propyl group, isopropyl group and tert-butyl group are more preferred, methyl group, ethyl group, isopropyl group and tert-butyl group are more preferred, and methyl group and tert-butyl group are particularly preferred.
Examples of the alicyclic hydrocarbon group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, an adamantyl group, and the like, preferably an aliphatic hydrocarbon group having 3 to 10 carbon atoms, more preferably an adamantyl group. It is.
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, preferably 1 to 1 carbon atoms. 6 is an alkoxy group, more preferably a methoxy group.
Examples of the alkylcarbonyloxy group include a methylcarbonyloxy group, an ethylcarbonyloxy group, an n-propylcarbonyloxy group, an isopropylcarbonyloxy group, an n-butylcarbonyloxy group, a sec-butylcarbonyloxy group, a tert-butylcarbonyloxy group, Examples thereof include a pentylcarbonyloxy group, a hexylcarbonyloxy group, an octylcarbonyloxy group and a 2-ethylhexylcarbonyloxy group, preferably an alkylcarbonyloxy group having 2 to 12 carbon atoms, more preferably a methylcarbonyloxy group. .
Examples of the arylcarbonyloxy group include a phenylcarbonyloxy group, a tosylcarbonyloxy group and the like, preferably an arylcarbonyloxy group having 7 to 12 carbon atoms, more preferably a phenylcarbonyloxy group.
As alkoxycarbonyloxy group, methoxycarbonyloxy group, ethoxycarbonyloxy group, n-propoxycarbonyloxy group, isopropoxycarbonyloxy group, n-butoxycarbonyloxy group, sec-butoxycarbonyloxy group, tert-butoxycarbonyloxy group A pentyloxycarbonyloxy group, a hexyloxycarbonyloxy group, an octyloxycarbonyloxy group, a 2-ethylhexyloxycarbonyloxy group, and the like, preferably an alkyloxycarbonyloxy group having 2 to 8 carbon atoms, more preferably a tert-butyloxycarbonyloxy group;
Ar is preferably a phenyl group which may have a substituent or a naphthyl group which may have a substituent. Examples of the substituent that Ar has include an alkyl group having 1 to 12 carbon atoms, a hydroxy group, and an alkoxy group having 1 to 18 carbon atoms (provided that —CH ₂ — contained in the alkoxy group having 1 to 18 carbon atoms is —O -Which may be replaced by-), preferably an alkyl group having 1 to 12 carbon atoms or an alkoxy group having 1 to 18 carbon atoms (provided that -CH _2- contained in the alkoxy group having 1 to 18 carbon atoms is- O— may be substituted.), More preferably, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 14 carbon atoms (provided that —CH ₂ — contained in the alkoxy group having 1 to 14 carbon atoms is , -O- may be substituted), and an alkyl group having 1 to 12 carbon atoms is more preferable.

Examples of the cation of the salt (I) include cations represented by the following formulas (Ic-1) to (Ic-22).

  Among them, formula (Ic-1), formula (Ic-3), formula (Ic-4), formula (Ic-7), formula (Ic-12), formula (I Ic-14), formula (Ic-16), formula (Ic-21) and cation represented by formula (Ic-22) are preferred.

The (1 + s) -valent aliphatic saturated hydrocarbon group having 1 to 18 carbon atoms represented by A ¹ is a group obtained by removing s hydrogen atoms from an alkyl group, or a group represented by formulas (KA-1) to (KA-19). (1 + s) hydrogen atoms removed from the cycloalkane represented by the above formula, or a (1 + s) -valent group in which two or more alkyl groups and cycloalkanes are combined to remove hydrogen atoms. . The s or (1 + s) hydrogen atoms may be removed from one carbon atom constituting the aliphatic saturated hydrocarbon group, or may be removed from two or more carbon atoms. The hydrogen atom contained in the (1 + s) -valent aliphatic saturated hydrocarbon group may be replaced with a hydroxy group.

［式（Ｘ^１−Ａ）〜式（Ｘ^１−Ｃ）中において、
Ｘ^１Ａは、炭素数１〜６のアルカンジイル基を表し、該アルカンジイル基に含まれる―ＣＨ_２−は、―Ｏ−又は―ＣＯ−で置き換わっていてもよい。
ｓは１〜３の整数を表す。ｓが１以上のとき、２つ以上のＸ^１Ａは同一又は相異なる。
ただし、式（Ｘ^１−Ａ）〜式（Ｘ^１−Ｃ）で表される基の総炭素数の上限は１８である。］ Examples of the (1 + s) -valent group in which a hydrogen atom is removed by combining an alkyl group and a cycloalkane include any of the formula (X ¹ -A), the formula (X ¹ -B), and the formula (X ¹ -C). Can be mentioned.

[In the formulas (X ¹ -A) to (X ¹ -C),
X ^1A represents an alkanediyl group having 1 to 6 carbon atoms, and —CH ₂ — contained in the alkanediyl group may be replaced by —O— or —CO—.
s represents an integer of 1 to 3. When s is 1 or more, two or more X ^1A are the same or different.
However, the upper limit of the total carbon number of the group represented by the formula (X ¹ -A) to the formula (X ¹ -C) is 18. ]

A ¹ is preferably an alkanediyl group having 2 to 8 carbon atoms or an alkanetriyl group having 2 to 8 carbon atoms, and more preferably an alkanediyl group.
Examples of the alkanediyl group having 1 to 8 carbon atoms include methylene group, ethylene group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, and hexane-1,6. -Linear alkanediyl group such as diyl group, ethane-1,1-diyl group, propane-1,2-diyl group, butane-1,3-diyl group, 2-methylpropane-1,3-diyl And branched alkanediyl groups such as 2-methylpropane-1,2-diyl group, pentane-1,4-diyl group and 2-methylbutane-1,4-diyl group. Among these, an alkanediyl group having 2 to 6 carbon atoms is more preferable, and an alkanediyl group having 2 to 4 carbon atoms is more preferable.

Examples of the alicyclic hydrocarbon group having 5 to 18 carbon atoms of R ³ include a cyclopentyl group, a cyclohexyl group, a norbornyl group, and an adamantyl group. Especially, a cyclopentyl group, a cyclohexyl group, and an adamantyl group are preferable, an adamantyl group and a cyclohexyl group are more preferable, and an adamantyl group is further more preferable.
As a ketal ring which may contain a fluorine atom in which two hydrogen atoms contained in an alicyclic hydrocarbon group are each replaced by an oxygen atom and combined with an alkanediyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon Two hydrogen atoms contained in one carbon atom constituting the group may each be replaced with an oxygen atom. The ketal ring includes * 1-O— (CH ₂ ) ₂ —O— * 2, * 1-O— (CH ₂ ) ₃ —O— * 2, * 1-O— (CH ₂ ) ₄ —O—. * 2, * 1-O- CH 2 - (CF 2) 2 -CH 2 -O- * 2, * 1-O-CH 2 - (CF 2) 3 -CH 2 -O- * 2, * 1- _{O-CH 2 - (CF 2} ) 4 -CH 2 -O- * 2 , and the like. Among them, * 1-O—CH ₂ — (CF ₂ ) ₂ —CH ₂ —O— * 2, * 1-O—CH ₂ — (CF ₂ ) ₃ —CH ₂ —O— * 2, * 1- _{O-CH 2 - (CF 2} ) 4 -CH 2 -O- * 2 are _{preferred, * 1-O-CH 2} - (CF 2) 2 -CH 2 -O- * 2, * 1-O-CH 2 _{- (CF 2) 3 -CH 2} -O- * 2 are more _{preferred, * 1-O-CH 2} - (CF 2) 2 -CH 2 -O- * 2 is more preferred. * 1 and * 2 each represent a bond, and * 1 and * 2 are bonded to the same carbon atom. Examples of the alkanediyl group forming the ketal ring include the same groups as those described above for A ¹ .

Examples of the anion (I) include the following anions. Especially, the anion represented by a formula (Ia-1)-a formula (Ia-8) is preferable.

In the salt (I) of the present invention, the above-mentioned cation and anion can be arbitrarily combined. Among these, preferred salts (I) are the salts described below.

（式中、Ｒ¹、Ｒ²、Ｒ^３、ｍ、ｎ、ｓ及びＡ¹は、前記と同義である。以下において同じ。）
溶剤としては、クロロホルム、ジクロロメタン、アセトニトリル等が挙げられる。 <Method for producing salt (I)>
The salt (I) can be produced by reacting the salt represented by the formula (Ia) and the compound represented by the formula (Ib) in a solvent.

(In the formula, R ¹ , R ² , R ³ , m, n, s and A ¹ have the same meanings as described above. The same shall apply hereinafter.)
Examples of the solvent include chloroform, dichloromethane, acetonitrile and the like.

溶剤としては、アセトニトリル、クロロホルム、水等が挙げられる。
式（Ｉ−ｄ）で表される塩は、下記式で表される化合物等が挙げられ、市場より容易に入手できる。

The salt (Ia) can be produced by reacting the salt represented by the formula (Ic) and the salt represented by the formula (Id) in a solvent.

Examples of the solvent include acetonitrile, chloroform, water and the like.
Examples of the salt represented by the formula (Id) include compounds represented by the following formula, and are easily available from the market.

触媒としては、酢酸銅（ＩＩ）等が挙げられる。
溶剤としては、クロロホルム等が挙げられる。
式（Ｉ−ｅ）で表される塩は、例えば、下記式で表される塩などが挙げられ、これらは市場から容易に入手できる。

式（Ｉ−ｆ）で表される化合物は、下記式で表される化合物などが挙げられ、これらは市場から容易に入手できる。

The salt represented by the formula (Ic) is produced by reacting the salt represented by the formula (Ie) and the compound represented by the formula (If) in a solvent in the presence of a catalyst. can do.

Examples of the catalyst include copper (II) acetate.
Examples of the solvent include chloroform.
Examples of the salt represented by the formula (Ie) include salts represented by the following formula, and these are easily available from the market.

Examples of the compound represented by the formula (If) include compounds represented by the following formulas, and these are easily available from the market.

（式中、Ｘは、塩素原子、臭素原子又はヨウ素原子を表す。） The salt represented by the formula (Ie) is produced by reacting the salt represented by the formula (Ig) and the compound represented by the formula (Ih) in a solvent such as chloroform. You can also

(In the formula, X represents a chlorine atom, a bromine atom or an iodine atom.)

Examples of the salt represented by the formula (Ig) include a salt represented by the following formula, and these can be easily obtained from the market.

溶剤としては、アセトニトリル、クロロホルム等が挙げられる。 The compound represented by the formula (Ib) can be produced by reacting the compound represented by the formula (Ii) and the compound represented by the formula (Ij) in a solvent. it can.

Examples of the solvent include acetonitrile and chloroform.

Examples of the compound represented by the formula (I-i) include compounds represented by the following formula, and are easily available from the market.

<Acid generator>
The acid generator of the present invention is also an acid generator containing salt (I). The acid generator of the present invention may contain an acid generator known in the resist field other than the salt (I) (hereinafter sometimes referred to as “acid generator (B)”). The acid generator (B) will be described later.
In addition, when the salt (I) and the acid generator (B) are contained as the acid generator, the ratio of the content of the salt (I) and the acid generator (B) (mass ratio; salt (I): acid generation The agent (B)) is usually 1:99 to 99: 1, preferably 2:98 to 98: 2, more preferably 5:95 to 95: 5, and even more preferably 10:90 to 90:10. It is.

<Resist composition>
The resist composition of the present invention contains a resin containing a structural unit having an acid labile group (hereinafter sometimes referred to as “resin (A)”) and a salt (I). The resist composition of the present invention may contain two or more kinds of salts (I).
The resist composition may contain an acid generator known in the resist field. The resist composition preferably contains a quencher (hereinafter sometimes referred to as “quencher (C)”), and preferably contains a solvent (hereinafter sometimes referred to as “solvent (E)”).

<Salt (I)>
The resist composition of the present invention preferably contains salt (I) as an acid generator. When salt (I) is used as an acid generator, the content of salt (I) is preferably 1 to 30% by mass and more preferably 1 to 20% by mass with respect to resin (A). Preferably, it is 2-15 mass%.

<Acid generator (B)>
As the acid generator (B), a known acid generator can be used, and either an ionic acid generator or a nonionic generator may be used. Preferably, it is an ionic acid generator. Examples of the ionic acid generator include an ionic acid generator composed of a combination of an anion (I) and a cation other than the cation (I), and an ionic acid generator composed of a combination of a known cation and a known anion. It is done.

Examples of the acid generator (B) include organic sulfonic acids and organic sulfonium salts. For example, acid generation described in JP2013-68914A, JP2013-3155A, and JP2013-11905A. Agents and the like. Specific examples include those represented by formula (B1-1) to formula (B1-40), preferably formula (B1-1), formula (B1-2), and formula containing an arylsulfonium cation. (B1-3), Formula (B1-5), Formula (B1-6), Formula (B1-7), Formula (B1-11), Formula (B1-12), Formula (B1-13), Formula ( B1-14), formula (B1-20), formula (B1-21), formula (B1-23), formula (B1-24), formula (B1-25), formula (B1-26), formula (B1) -29), Formula (B1-31), Formula (B1-32), Formula (B1-33), Formula (B1-34), Formula (B1-35), Formula (B1-36), Formula (B1- 37), a salt represented by any one of formula (B1-38), formula (B1-39) or formula (B1-40) is more preferred.

An acid generator (B) may contain 2 or more types.
The content of the acid generator (B) is preferably 1 to 30% by mass, more preferably 1 to 20% by mass, and 3 to 15% by mass with respect to the resin (A). Is more preferable.
In the resist composition, when the salt (I) and the acid generator (B) are used as the acid generator, the total content of the salt (I) and the acid generator (B) is based on the resin (A). Preferably it is 1.5 mass% or more (more preferably 3 mass% or more), preferably 40 mass% or less (more preferably 35 mass% or less).

<Resin (A)>
The resin (A) has a structural unit having an acid labile group (hereinafter sometimes referred to as “structural unit (a1)”). Here, the “acid labile group” has a leaving group, the leaving group is eliminated by contact with an acid, and the structural unit is a hydrophilic group (for example, a hydroxy group, a carboxy group or a sulfhydryl group). This means a group that is converted into a structural unit.
The resin (A) preferably further contains a structural unit other than the structural unit (a1). Examples of the structural unit other than the structural unit (a1) include a structural unit having no acid labile group (hereinafter sometimes referred to as “structural unit (s)”).

［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み合わせた基を表すか、Ｒ^a1及びＲ^a2は互いに結合してそれらが結合する炭素原子とともに炭素数３〜２０の２価の脂環式炭化水素基を形成する。
ｎａは、０又は１を表す。
＊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’は互いに結合してそれらが結合する炭素原子及びＸとともに炭素数３〜２０の２価の複素環基を形成し、該炭化水素基及び該２価の複素環基に含まれる−ＣＨ₂−は、−Ｏ−又は−Ｓ−で置き換わってもよい。
Ｘは、酸素原子又は硫黄原子を表す。
＊は酸素原子又は硫黄原子との結合手を表す。］ <Structural unit (a1)>
The structural unit (a1) is derived from a monomer having an acid labile group (hereinafter sometimes referred to as “monomer (a1)”).
The acid labile group contained in the structural unit (I) constituting the resin (A) is a group represented by the formula (1) (hereinafter sometimes referred to as the group (1)) and / or the formula (2). (Hereinafter, sometimes referred to as group (2)) is preferred.

[In the formula (1), R ^{a1 to} R ^a3 each independently represents an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or a combination of these, or R ^a1 and R ^a2 are bonded to each other to form a divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms together with the carbon atom to which they are bonded.
na represents 0 or 1.
* 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 heterocyclic group having 3 to 20 carbon atoms together with the carbon atom to which they are bonded and X, and the hydrocarbon group and the divalent —CH ₂ — contained in the ring group may be replaced by —O— or —S—.
X represents an oxygen atom or a sulfur atom.
* Represents a bond with an oxygen atom or a sulfur atom. ]

アルキル基と脂環式炭化水素基とを組み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、シクロヘキシルメチル基、アダマンチルメチル基、ノルボルニルエチル基等が挙げられる。
ｎａは、好ましくは０である。 ^Examples of the alkyl group represented by R ^{a1 to} R ^a3 include a methyl group, an ethyl group, a propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, and an n-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 decahydronaphthyl group, adamantyl group, norbornyl group, and the following groups (* represents a bond). The alicyclic hydrocarbon group of R ^{a1 to} R ^a3 is preferably an alicyclic hydrocarbon group having 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, a methylnorbornyl group, a cyclohexylmethyl group, an adamantylmethyl group, and a norbornylethyl group. Can be mentioned.
na is preferably 0.

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 alicyclic hydrocarbon group include the following groups. The divalent alicyclic hydrocarbon group preferably has 3 to 12 carbon atoms. * Represents a bond with -O-.

Examples of the group represented by the formula (1) include a 1,1-dialkylalkoxycarbonyl group (a group in which R ^{a1 to} R ^a3 are alkyl groups in the formula (1), preferably a tert-butoxycarbonyl group), 2- An alkyladamantan-2-yloxycarbonyl group (in the formula (1), R ^a1 , R ^a2 and a carbon atom to which they are bonded 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).

Ｒ^a1’及びＲ^a2’のうち、少なくとも１つは水素原子であることが好ましい。 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 formed by combining these.
Examples of the alkyl group and alicyclic hydrocarbon group are the same as those described above.
Examples of the aromatic hydrocarbon group include a phenyl group, a naphthyl group, an anthryl group, a biphenyl group, and an aryl group such as a phenanthryl group.
Examples of the group formed by combining these include an alkyl-cycloalkyl group, a cycloalkyl-alkyl group, an aralkyl group (for example, phenylmethyl group, 1-phenylethyl group, 2-phenylethyl group, 1-phenyl-1 -Propyl group, 1-phenyl-2-propyl group, 2-phenyl-2-propyl group, 3-phenyl-1-propyl group, 4-phenyl-1-butyl group, 5-phenyl-1-pentyl group, 6 Alkyl-aryl groups (for example, 2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 4-ethylphenyl group, 4-propylphenyl group, 4-phenyl-1-hexyl group, etc.) Isopropylphenyl group, 4-butylphenyl group, 4-t-butylphenyl group, 4-hexylphenyl group, 4-cyclohexyl Enyl group, tolyl group, xylyl group, cumenyl group, mesityl group, 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl group, etc.), aryl-cycloalkyl group, cycloalkyl-aryl group (for example, p -An adamantylphenyl group).
^{Examples of the} divalent heterocyclic group formed together with the carbon atom and X to which R ^{a2 ′} and R ^{a3 ′} are bonded to each other and X include the following groups. * Represents a bond.

At least one of R ^{a1 ′} and R ^{a2 ′} is preferably 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.

［式（ａ１−０）中、
Ｌ^a01は、酸素原子又は^＊−Ｏ−（ＣＨ₂）_k01−ＣＯ−Ｏ−を表し、ｋ０１は１〜７の整数を表し、＊はカルボニル基との結合手を表す。
Ｒ^a01は、水素原子又はメチル基を表す。
Ｒ^a02、Ｒ^a03及びＲ^a04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み合わせた基を表す。］

［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み合わせることにより形成される基を表す。
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。］ As a structural unit derived from a (meth) acrylic monomer having a group represented by the formula (1), a structural unit represented by the formula (a1-0) is preferably represented by the formula (a1-1). The structural unit represented by a structural unit or a formula (a1-2) is mentioned. Two or more of these may be used in combination. In this specification, the structural unit represented by formula (a1-0), the structural unit represented by formula (a1-1), and the structural unit represented by formula (a1-2) are each represented by structural unit (a1). -0), structural unit (a1-1) and structural unit (a1-2), a monomer for deriving structural unit (a1-0), a monomer for deriving structural unit (a1-1), and a structural unit (a1- The monomer that induces 2) may be referred to as monomer (a1-0), monomer (a1-1), and monomer (a1-2), respectively.

[In the formula (a1-0),
L ^a01 represents an oxygen atom or ^* —O— (CH ₂ ) _k01 —CO—O—, k01 represents an integer of 1 to 7, and * represents a bond to a carbonyl group.
R ^a01 represents a hydrogen atom or a methyl group.
R ^a02 , R ^a03 and R ^a04 each independently ^represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a combination thereof. ]

[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 formed 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 ^a01 is preferably an oxygen atom or ^* —O— (CH ₂ ) _k01 —CO—O— (where k01 is preferably an integer of 1 to 4, more preferably 1), and more. Preferably it is an oxygen atom.
Examples of the alkyl group of R ^a02 , R ^a03, and R ^a04 , the alicyclic hydrocarbon group, and a 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 ^a02 , R ^a03 and R ^a04 preferably has 6 or less carbon atoms.
The alicyclic hydrocarbon group ^{represented by} R ^a02 , R ^a03 and R ^a04 preferably has 8 or less carbon atoms, more preferably 6 or less.
The group combining the alkyl group and the alicyclic hydrocarbon group preferably has a total carbon number of 18 or less, combining the alkyl group and the alicyclic hydrocarbon group. Examples of such groups include a methylcyclohexyl group, a dimethylcyclohexyl group, a methylnorbornyl group, a methyladamantyl group, a cyclohexylmethyl group, a methylcyclohexylmethyl group, an adamantylmethyl group, and a norbornylmethyl group. It is done.
R ^a02 and R ^a03 are preferably an alkyl group having 1 to 6 carbon atoms, more preferably a methyl group or an ethyl group.
R ^a04 is preferably an alkyl group having 1 to 6 carbon atoms or an alicyclic hydrocarbon group having 5 to 12 carbon atoms, and more preferably a methyl group, an ethyl group, a cyclohexyl group, or an adamantyl group.

L ^a1 and L ^a2 are preferably —O— or ^* —O— (CH ₂ ) _{k1 ′} —CO—O— (where k1 ′ is an integer of 1 to 4, preferably 1). More preferably -O-.
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 a 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 is preferably an alicyclic hydrocarbon group having 8 or less carbon atoms, more preferably an alicyclic hydrocarbon group having 6 or less carbon atoms.
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 the monomer (a1-0), for example, a monomer represented by any one of the formulas (a1-0-1) to (a1-0-12) is preferable, and the formula (a1-0-1) to the formula ( A monomer represented by any one of a1-0-10) is more preferable.

In the above structural unit, a structural unit in which a methyl group corresponding to R ^a01 is replaced with a hydrogen atom can also be given as a specific example of the structural unit (a1-0).

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 monomers represented by any of the formulas (a1-2-1) to (a1-2-12), and include the formula (a1-2-3) and the formula (a1). -2-4), a monomer represented by formula (a1-2-9) or formula (a1-2-10) is preferable, and a monomer represented by formula (a1-2-3) or formula (a1-2-9) More preferred is a monomer.

  When the resin (A) includes the structural unit (a1-0) and / or the structural unit (a1-1) and / or the structural unit (a1-2), the total content thereof is the total structure of the resin (A). It is 10-95 mol% normally with respect to a unit, Preferably it is 15-90 mol%, More preferably, it is 20-85 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ることにより形成される基を表し、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−ＣＨ₂−は、−Ｏ−又は−ＣＯ−に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み合わせることにより形成される基を表すか、Ｒ^a10及びＲ^a11は互いに結合して、それらが結合する炭素原子とともに炭素数３〜２０の２価の脂環式炭化水素基を形成する。］ Further, examples of the structural unit (a1) having the group (1) include a structural unit represented by the formula (a1-3). The structural unit represented by the formula (a1-3) may be referred to as a structural unit (a1-3). Moreover, the monomer which derives the structural unit (a1-3) may be referred to as a monomer (a1-3).

[In the 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 group formed by a combination thereof, the aliphatic hydrocarbon group and the The hydrogen atom contained in the alicyclic hydrocarbon group may be substituted with a hydroxy group, and —CH ₂ — contained in the aliphatic hydrocarbon group and the alicyclic hydrocarbon group is —O— or -CO- may be substituted.
R ^a10 , R ^a11 and R ^a12 each independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or a group formed by combining these, or R ^a10 and R ^a11 are bonded to each other to form a divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms together with the carbon atom to which they are bonded. ]

Here, -COOR ^a13 includes, for example, 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 of R ^a9 include a methyl group, an ethyl group, a propyl group, a hydroxymethyl group and a 2-hydroxyethyl group.
^Examples of the aliphatic hydrocarbon group having 1 to 8 carbon atoms represented by R ^a13 include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, n -Hexyl group, n-heptyl group, 2-ethylhexyl group, n-octyl group, etc. are mentioned.
^Examples of the alicyclic hydrocarbon group having 3 to 20 carbon atoms represented by R ^a13 include a cyclopentyl group, a cyclopropyl group, an adamantyl group, an adamantylmethyl group, a 1-adamantyl-1-methylethyl group, and 2-oxo-oxolane-3- Yl group and 2-oxo-oxolan-4-yl group.
^Examples of the alkyl group represented by R ^{a10 to} R ^a12 include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, Examples include n-heptyl group, 2-ethylhexyl group, n-octyl group and the like.
The alicyclic hydrocarbon group for R ^{a10 to} R ^a12 may be monocyclic or polycyclic, and examples of the monocyclic alicyclic hydrocarbon group include a cyclopropyl group, a cyclobutyl group, and cyclopentyl. Cycloalkyl groups such as a group, a cyclohexyl group, a methylcyclohexyl group, a dimethylcyclohexyl group, a cycloheptyl group, a cyclooctyl group, and a 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, isobornyl group and the like.
-C (R ^a10 ) (R ^a11 ) (R ^a12 ) in the case where R ^a10 and R ^a11 are bonded to each other to form a divalent alicyclic hydrocarbon group together with the carbon atom to which they are bonded 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) contains the structural unit (a1-3), the content thereof 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及びＲ^a35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^a36は、炭素数１〜２０の炭化水素基を表すか、Ｒ^a35及びＲ^a36は互いに結合してそれらが結合するＣ−Ｏとともに炭素数３〜２０の２価の複素環基を形成し、該炭化水素基及び該２価の複素環基に含まれる−ＣＨ₂−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 group (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 and R ^a35 each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, R ^a36 may represent a hydrocarbon group having 1 to 20 carbon atoms, R ^a35 and R ^a36 are bonded to each other And C—O to which they are bonded to form a divalent heterocyclic group having 3 to 20 carbon atoms, and —CH ₂ — contained in the hydrocarbon group and the divalent heterocyclic group is —O— Alternatively, it may be replaced by -S-. ]

^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.
Examples of the hydrocarbon group R ^a34 and R ^a35, include the same groups as R ^{a1 'and} R ^a2' of formula (2).
The R ^a36, include groups formed by alkyl groups having 1 to 18 carbon atoms, alicyclic hydrocarbon group having 3 to 18 carbon atoms, or these aromatic hydrocarbon group having 6 to 18 carbon atoms combined It is done.

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 R ^a36 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. It is a group to be formed, more preferably an alkyl group having 1 to 18 carbon atoms, an alicyclic aliphatic hydrocarbon group having 3 to 18 carbon atoms, or an aralkyl group having 7 to 18 carbon atoms. The alkyl group in R ^a36 and the alicyclic hydrocarbon group are preferably unsubstituted. When the aromatic hydrocarbon group in R ^a36 has a substituent, the substituent is preferably an aryloxy group having 6 to 10 carbon atoms.

As a monomer which introduce | transduces structural unit (a1-4), the monomer described in Unexamined-Japanese-Patent No. 2010-204646 is mentioned, for example. Among these, monomers represented by formula (a1-4-1) to formula (a1-4-8) are preferable, and formula (a1-4-1) to formula (a1-4-5) and formula (a1- The monomers represented by 4-8) are 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^a8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）_h3−ＣＯ−Ｌ⁵⁴−を表し、ｈ３は１〜４の整数を表し、＊は、Ｌ⁵¹との結合手を表す。
Ｌ⁵¹、Ｌ⁵²、Ｌ⁵³及びＬ⁵⁴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。 As a structural unit derived from a (meth) acrylic monomer having a group represented by the formula (2), a structural unit represented by the formula (a1-5) (hereinafter referred to as “structural unit (a1-5)”) Is also included).

In formula (a1-5),
R ^a8 represents a C 1-6 alkyl group optionally having a halogen atom, a hydrogen atom, or a halogen atom.
Z ^a1 represents a single bond or * — (CH ₂ ) _h3 —CO—L ⁵⁴ —, h3 represents an integer of 1 to 4, and * represents a bond to L ⁵¹ .
L ⁵¹ , L ⁵² , L ⁵³ and L ⁵⁴ each independently represent —O— or —S—.
s1 represents an integer of 1 to 3.
s1 ′ represents an integer of 0 to 3.

Examples of the halogen atom include a fluorine atom and a chlorine atom, and a fluorine atom is preferable. Examples of the alkyl group having 1 to 6 carbon atoms which may have a halogen atom 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 fluoromethyl group and a trifluoromethyl group. Groups.
In formula (a1-5), R ^a8 is preferably a hydrogen atom, a methyl group or a trifluoromethyl group.
L ⁵¹ is preferably an oxygen atom.
Of L ⁵² and L ⁵³ , one is preferably —O— and the other is preferably —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 which introduce | transduces structural unit (a1-5), the monomer described in Unexamined-Japanese-Patent No. 2010-61117 is mentioned, for example. Among these, structural units each represented by formula (a1-5-1) to formula (a1-5-4) are preferable, and are represented by formula (a1-5-1) or formula (a1-5-2). A structural unit is more preferable.

  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.

The structural unit (a) having an acid labile group in the resin (A) includes the structural unit (a1-0), the structural unit (a1-1), the structural unit (a1-2), and the structural unit (a1-5). ) Is preferably at least one selected from the group consisting of, and more preferably at least two, a combination of structural unit (a1-1) and structural unit (a1-2), structural unit (a1-1) and structural unit ( a1-5), a structural unit (a1-1) and a structural unit (a1-0), a structural unit (a1-2) and a structural unit (a1-0), and a structural unit (a1-5) And a combination of the structural unit (a1-0), a structural unit (a1-0), a combination of the structural unit (a1-1) and the structural unit (a1-2), a structural unit (a1-0), and a structural unit (a1- 1) and structural unit (a1-5) More preferably a combination, the combination of the structural units (a1-1) and the structural unit (a1-2), more preferably a combination of structural units (a1-1) and the structural unit (a1-5).
The structural unit (a1) preferably includes the structural unit (a1-1) or includes the structural unit (a1-2), and more preferably includes the structural unit (a1-1).

<Structural unit (s)>
The structural unit (s) is derived from a monomer having no acid labile group (hereinafter sometimes referred to as “monomer (s)”). As the monomer for deriving the structural unit (s), a monomer having no acid labile group known in the resist field can be used.
As the structural unit (s), a structural unit having a hydroxy group or a lactone ring and having no acid labile group is preferable. A structure having a hydroxy group and having no acid labile group (hereinafter sometimes referred to as “structural unit (a2)”) and / or a lactone ring and having no acid labile group If a resin having a unit (hereinafter sometimes referred to as “structural unit (a3)”) is used in the resist composition of the present invention, 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.
When a resist pattern is produced from the resist composition of the present invention, when a high energy beam such as a KrF excimer laser (248 nm), an electron beam or EUV (ultra-ultraviolet light) is used as an exposure light source, the structural unit (a2) It is preferable to use the structural unit (a2) having a phenolic hydroxy group. When an ArF excimer laser (193 nm) or the like is used, the structural unit (a2) having an alcoholic hydroxy group is preferable as the structural unit (a2), and the structural unit (a2-1) is more preferable. As a structural unit (a2), 12 or more types may be included.

［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 include a methyl group, an ethyl group, a propyl group, a butyl group, an n-pentyl group, and an n-hexyl group.
Examples of the halogen atom include a fluorine atom, a chlorine atom and a bromine atom.
^Examples of the alkyl group having 1 to 6 carbon atoms which may have a halogen atom of R ^a30 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, n-pentyl group, n-hexyl Group, n-perfluorohexyl group and the like. 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.
^Examples of the alkoxy group for R ^a31 include a methoxy group, an ethoxy group, a propoxy group, and a butoxy group. Especially, a C1-C4 alkoxy group is preferable, a methoxy group or an ethoxy group is more preferable, and a methoxy group is further more preferable.
Examples of the acyl group for R ^a31 include an acetyl group, a propionyl group, and a butyryl group.
^Examples of the acyloxy group for R ^a31 include an acetyloxy group, a propionyloxy group, and a butyryloxy group.
As ma, 0, 1 or 2 is preferable, 0 or 1 is more preferable, and 0 is more preferable.

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. The structural unit represented by the formula (a2-0-1) or the formula (a2-0-2) is more preferable.

  The resin (A) containing the structural unit (a2-0) is subjected to a polymerization reaction 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, and then deprotected. It can be manufactured by processing. However, when the deprotection treatment is performed, the acid labile group of the structural unit (a1) needs to be not significantly impaired. Examples of such protecting groups include acetyl groups.

  When the resin (A) has a structural unit (a2-0) having a phenolic hydroxy group, the content is preferably from 5 to 95 mol% with respect to all the structural units of the resin (A). 80 mol% is more preferable, and 15-80 mol% is further 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), 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, it is 1-35 mol%, More preferably, it is 2-20 mol%.

<Structural unit (a3)>
The lactone ring of the structural unit (a3) may be a monocycle such as a β-propiolactone ring, γ-butyrolactone ring, or δ-valerolactone ring, or a condensed ring of a monocyclic lactone ring and another ring. But you can. Preferably, a γ-butyrolactone ring, an adamantane lactone ring, or a bridged ring containing a γ-butyrolactone ring structure is used.

  The structural unit (a3) is preferably a structural unit represented by the formula (a3-1), the formula (a3-2), the formula (a3-3), or the formula (a3-4). These may contain 2 or more types.

［式（ａ３−１）中、
Ｌ^a4は、−Ｏ−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、−Ｏ−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、−Ｏ−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。
式（ａ３−４）中、
Ｒ^a24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。
Ｒ^ａ２５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。
Ｌ^a7は、単結合、^＊−Ｌ^a8−Ｏ−、^＊−Ｌ^a8−ＣＯ−Ｏ−、^＊−Ｌ^a8−ＣＯ−Ｏ−Ｌ^a9−ＣＯ−Ｏ−又は^＊−Ｌ^a8−Ｏ−ＣＯ−Ｌ^a9−Ｏ−を表す。
＊は−Ｏ−との結合手を表す。
Ｌ^a8及びＬ^a9は、互いに独立に、炭素数１〜６のアルカンジイル基を表す。
ｗ１は、０〜８の整数を表す。ｗ１が２以上のとき、複数のＲ^ａ２５は互いに同一であってもよく、異なってもよい。］

[In the formula (a3-1),
L ^a4 represents —O— or ^* —O— (CH ₂ ) _k3 —CO—O— (k3 represents an integer of 1 to 7).
) Represents a group represented by * 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 —O— or ^* —O— (CH ₂ ) _k3 —CO—O— (k3 represents an integer of 1 to 7).
) Represents a group represented by * 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 —O— or ^* —O— (CH ₂ ) _k3 —CO—O— (k3 represents an integer of 1 to 7).
) Represents a group represented by * 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 formula (a3-4),
R ^a24 represents an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, a hydrogen atom or a halogen atom.
R ^a25 represents a carboxy group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
L ^a7 is a single bond, ^* —L ^a8 —O—, ^* —L ^a8 —CO—O—, ^* —L ^a8 —CO—O—L ^a9 —CO—O— or ^* —L ^a8 —O—CO —L ^a9 —O— is represented.
* Represents a bond with -O-.
L ^a8 and L ^a9 each independently represent an alkanediyl group having 1 to 6 carbon atoms.
w1 represents an integer of 0 to 8. When w1 is 2 or more, the plurality of R ^a25 may be the same as or different from each other. ]

Examples of the aliphatic hydrocarbon group such as R ^a21 include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, and a tert-butyl group.
Examples of the halogen atom for R ^a24 include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
^Examples of the alkyl group for R ^a24 include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, and n-hexyl group. , Preferably it is a C1-C4 alkyl group, More preferably, it is a methyl group or an ethyl group.
Examples of the alkyl group having a halogen atom of R ^a24 include trifluoromethyl group, perfluoroethyl group, perfluoropropyl group, perfluoroisopropyl group, perfluorobutyl group, perfluorosec-butyl group, perfluorotert-butyl group, perfluoropentyl group, perfluoro group. A hexyl group, a trichloromethyl group, a tribromomethyl group, a triiodomethyl group, etc. are mentioned.

^Examples of the alkanediyl group represented by L ^a8 and L ^a9 include a methylene group, an ethylene group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane-1,4-diyl group, and a pentane-1,5. -Diyl group, hexane-1,6-diyl group, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1, 4-diyl group, 2-methylbutane-1,4-diyl group, etc. are mentioned.

In formula (a3-1) to formula (a3-3), L ^{a4 to} L ^a6 are each independently preferably —O— or k— is an integer of 1 to 4 * —O— (CH ₂ ) A group represented by _{k 3} —CO—O—, more preferably —O— 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 to 2, more preferably 0 or 1.

（式中、Ｒ^a24、Ｌ^ａ７は、上記と同じ意味を表す。） In formula (a3-4),
R ^a24 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 still more preferably a hydrogen atom or a methyl group.
L ^a7 is preferably a single bond or ^* -L ^a8 —CO—O—, and more preferably a single bond, —CH ₂ —CO—O— or —C ₂ H ₄ —CO—O—. .
R ^a25 is preferably a carboxy group, a cyano group, or a methyl group.
w1 is preferably an integer of 0 to 2, more preferably 0 or 1.
In particular, the formula (a3-4) is preferably the formula (a3-4) ′.

(Wherein R ^a24 and L ^a7 represent the same meaning as described above.)

As monomers for deriving the structural unit (a3), monomers described in JP 2010-204646 A, monomers described in JP 2000-122294 A, monomers described in JP 2012-41274 A are listed. Can be mentioned. As the structural unit (a3), formula (a3-1-1) to formula (a3-1-4), formula (a3-2-1) to formula (a3-2-4), formula (a3-3) 1) to a structural unit represented by any one of the formula (a3-3-4) and the formula (a3-4-1) to the formula (a3-4-12), the formula (a3-1-1), It is represented by any one of formula (a3-1-2), formula (a3-2-3) to formula (a3-2-4) and formula (a3-4-1) to formula (a3-4-12) The structural unit represented by any one of formulas (a3-4-1) to (a3-4-12) is more preferred, and the structural unit represented by formula (a3-4-1) to formula (a3- The structural unit represented by any one of 4-6) is even more preferable.

In the structural units represented by the following formulas (a3-4-1) to (a3-4-12), compounds in which the methyl group corresponding to R ^a24 is replaced with a hydrogen atom are also structural units (a3-4). ).

When the resin (A) includes the structural unit (a3), the total content is usually 5 to 70 mol%, preferably 10 to 65 mol%, based on all the structural units of the resin (A). More preferably, it is 10-60 mol%.
Moreover, the content rate of a structural unit (a3-1), a structural unit (a3-2), a structural unit (a3-3), and a structural unit (a3-4) is respectively with respect to all the structural units of resin (A). 5 to 60 mol% is preferable, 5 to 50 mol% is more preferable, and 10 to 50 mol% is more preferable.

<Other structural units (t)>
The resin (A) may contain other structural units (hereinafter sometimes referred to as “structural units (t)”) as structural units other than the structural units (a1) and (s). As the structural unit (t), in addition to the structural unit (a2) and the structural unit (a3), a structural unit having a halogen atom (hereinafter sometimes referred to as “structural unit (a4)”) and a non-leaving hydrocarbon group. And a structural unit (s) (hereinafter sometimes referred to as “structural unit (a5)”). 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.

［式（ａ４−０）中、
Ｒ⁵は、水素原子又はメチル基を表す。
Ｌ⁴は、単結合又は炭素数１〜４の脂肪族飽和炭化水素基を表す。
Ｌ³は、炭素数１〜８のペルフルオロアルカンジイル基又は炭素数３〜１２のペルフルオロシクロアルカンジイル基を表す。
Ｒ⁶は、水素原子又はフッ素原子を表す。］ As the structural unit (a4), a structural unit represented by formula (a4-0) can be given.

[In the formula (a4-0),
R ⁵ represents a hydrogen atom or a methyl group.
L ⁴ represents a single bond or an aliphatic saturated hydrocarbon group having 1 to 4 carbon atoms.
L ³ represents a perfluoroalkyl cycloalkanediyl group perfluoro alkanediyl group or 3 to 12 carbon atoms having 1 to 8 carbon atoms.
R ⁶ represents a hydrogen atom or a fluorine atom. ]

As the aliphatic saturated hydrocarbon group for L ⁴ , a linear alkanediyl group such as methylene group, ethylene group, propane-1,3-diyl group, butane-1,4-diyl group, ethane-1,1- Branched alkanediyl such as diyl group, propane-1,2-diyl group, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group and 2-methylpropane-1,2-diyl group Groups.

As the perfluoroalkanediyl group of L ³ , a difluoromethylene group, a perfluoroethylene group, a perfluoroethylfluoromethylene group, a perfluoropropane-1,3-diyl group, a perfluoropropane-1,2-diyl group, a perfluoropropane-2,2 -Diyl group, perfluorobutane-1,4-diyl group, perfluorobutane-2,2-diyl group, perfluorobutane-1,2-diyl group, perfluoropentane-1,5-diyl group, perfluoropentane-2,2 -Diyl group, perfluoropentane-3,3-diyl group, perfluorohexane-1,6-diyl group, perfluorohexane-2,2-diyl group, perfluorohexane-3,3-diyl group, perfluoroheptane-1,7 -Diyl group, perfluoroheptane-2 2-diyl group, perfluoroheptane-3,4-diyl group, perfluoroheptane-4,4-diyl group, perfluorooctane-1,8-diyl group, perfluorooctane-2,2-diyl group, perfluorooctane-3, A 3-diyl group, a perfluorooctane-4,4-diyl group, etc. are mentioned.
Examples of the L ³ perfluorocycloalkanediyl group include a perfluorocyclohexanediyl group, a perfluorocyclopentanediyl group, a perfluorocycloheptanediyl group, and a perfluoroadamantanediyl group.

L ⁴ is preferably a single bond, a methylene group or an ethylene group, and more preferably a single bond or a methylene group.
L ³ is preferably a C 1-6 perfluoroalkanediyl group, more preferably a C 1-3 perfluoroalkanediyl group.

Examples of the structural unit (a4-0) include the structural units shown below.

In the compounds represented by formula (a4-0-1) to formula (a4-0-16), a compound in which the methyl group corresponding to R ⁵ is replaced by a hydrogen atom is also represented by formula (a4-0). Specific examples of the structural unit can be given.

［式（ａ４−１）中、
Ｒ^a41は、水素原子又はメチル基を表す。
Ｒ^a42は、置換基を有していてもよい炭素数１〜２０の炭化水素基を表し、該炭化水素基に含まれる−ＣＨ₂−は、−Ｏ−又は−ＣＯ−に置き換わっていてもよい。
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）で表される基を表す。

〔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、単結合又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７以下である。〕
＊、＊＊は結合手であり、＊＊は−Ｏ−ＣＯ−Ｒ^a42との結合手である。］ As the structural unit (a4), a structural unit represented by formula (a4-1) can be given.

[In the formula (a4-1),
R ^a41 represents a hydrogen atom or a methyl group.
R ^a42 represents an ^optionally substituted hydrocarbon group having 1 to 20 carbon atoms, and —CH ₂ — contained in the hydrocarbon group may be replaced by —O— or —CO—. Good.
A ^a41 represents an ^optionally substituted alkanediyl group having 1 to 6 carbon atoms or a group represented by the 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 a single bond or a ^C1-C5 aliphatic hydrocarbon group which may have a substituent.
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 7 or less. ]
* And ** are bonds, and ** is a bond with -O-CO-R ^a42 . ]

^Examples of the hydrocarbon group for R ^a42 include chain and cyclic aliphatic hydrocarbon groups, aromatic hydrocarbon groups, and groups formed by combining these.
The chain and cyclic aliphatic hydrocarbon groups may have carbon-carbon unsaturated bonds, but are formed by chain and cyclic aliphatic saturated hydrocarbon groups and combinations thereof. Groups are preferred. The aliphatic saturated hydrocarbon group includes a straight chain or branched alkyl group and a monocyclic or polycyclic alicyclic hydrocarbon group, and an aliphatic group formed by combining 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、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が挙げられる。 Examples of chain aliphatic hydrocarbon groups include methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, and n-decyl. Group, n-dodecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group and n-octadecyl group. Cyclic aliphatic hydrocarbon groups include cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group and other cycloalkyl groups; decahydronaphthyl group, adamantyl group, norbornyl group and the following groups (* is a bond) And a polycyclic alicyclic hydrocarbon group such as “represents a hand.”

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１〜１７の脂肪族炭化水素基を表す。
＊は、結合手を表す。］
Ａ^a45の脂肪族炭化水素基としては、Ｒ^a42で例示したものと同様の基が挙げられる。
Ｒ^a42がハロゲン原子を有する脂肪族炭化水素基である場合、好ましくはフッ素原子を有する脂肪族炭化水素基であり、より好ましくはペルフルオロアルキル基又はペルフルオロシクロアルキル基であり、さらに好ましくは炭素数が１〜６のペルフルオロアルキル基であり、特に好ましくは炭素数１〜３のペルフルオロアルキル基である。ペルフルオロアルキル基としては、ペルフルオロメチル基、ペルフルオロエチル基、ペルフルオロプロピル基、ペルフルオロブチル基、ペルフルオロペンチル基、ペルフルオロヘキシル基、ペルフルオロヘプチル基及びペルフルオロオクチル基等が挙げられる。ペルフルオロシクロアルキル基としては、ペルフルオロシクロヘキシル基等が挙げられる。
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。
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。 ^Examples of the substituent for R ^a42 include a halogen atom and a group represented by the formula (a-g3). As a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom are mentioned, Preferably a fluorine atom is mentioned.

[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 ^1-17 aliphatic hydrocarbon group having at least one halogen atom.
* Represents a bond. ]
^As the aliphatic hydrocarbon group for A ^a45, the same groups as those exemplified for R ^a42 can be mentioned.
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.
When R ^a42 is an aliphatic hydrocarbon group having a group represented by the formula (a-g3), including the carbon number 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.
When R ^a42 is an aliphatic hydrocarbon group having a group represented by the formula (a-g3), including the carbon number 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１〜１７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１〜１７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。
＊はカルボニル基との結合手を表す。］ The aliphatic hydrocarbon group 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 1 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 1 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.
* Represents a bond with a carbonyl 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.

A more preferred structure of the partial structure represented by * -A ^a46 -X ^a44 -A ^a47 (* is a bond to a carbonyl group) is the following structure.

^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-1,2-diyl group, 1-methylbutane-1,4-diyl group, Examples include branched alkanediyl groups such as 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.

The aliphatic hydrocarbon group for A ^a42 , A ^a43 and A ^{a44 in} the group (a-g1) may have a carbon-carbon unsaturated bond, but is preferably an aliphatic saturated hydrocarbon group. . As the aliphatic saturated hydrocarbon group, an alkyl group (the alkyl group may be linear or branched), an alicyclic hydrocarbon group, and an alkyl group and an alicyclic hydrocarbon group are combined. An aliphatic hydrocarbon group formed by the above. Specifically, methylene group, ethylene group, propane-1,3-diyl group, propane-1,2-diyl group, butane-1,4-diyl group, 1-methylpropane-1,3-diyl group, Examples include 2-methylpropane-1,3-diyl group and 2-methylpropane-1,2-diyl group. Examples of these substituents include a hydroxy group and an alkoxy group having 1 to 6 carbon atoms.
s is preferably 0.

^Examples of the group ( ^{ag1) in} which X ^a42 represents an oxygen atom, a carbonyl group, a carbonyloxy group or an oxycarbonyl group include the following groups. In the following examples, * and ** each represent a bond, and ** is a bond with —O—CO—R ^a42 .

［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), structural units represented by the formula (a4-2) and the formula (a4-3) are 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 of R ^f2 includes an aliphatic hydrocarbon group and an aromatic hydrocarbon group, and the aliphatic hydrocarbon group includes a chain, a cyclic group, and a group formed by 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, n-pentyl group, n-hexyl group, n-octyl group and 2 -An ethylhexyl group is mentioned.
The alicyclic hydrocarbon group may be monocyclic or polycyclic. Examples of monocyclic alicyclic hydrocarbon groups include cyclopropyl groups such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, methylcyclohexyl group, dimethylcyclohexyl group, cycloheptyl group, cyclooctyl group, and cyclodecyl group. Can be mentioned. 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, norbornyl group, A methyl norbornyl group and an isobornyl group are mentioned.

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.
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, a 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, 1- (trifluoromethyl) -2,2,2-trifluoroethyl 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- (perfluoropropyl) 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, 2- (perfluoro Butyl) ethyl group, 1,1,2,2,3,3,4,4,5,5-decafluorohexyl group, 1,1,2,2,3,3,4,4,5,5 Fluorinated alkyl groups such as 6,6-dodecafluorohexyl group, perfluoropentylmethyl group and perfluorohexyl group can be mentioned.
Examples of the alicyclic hydrocarbon group having a fluorine atom include fluorinated cycloalkyl groups such as a perfluorocyclohexyl group and a perfluoroadamantyl group.

As A ^f1 in formula (a4-2), an alkanediyl group having 2 to 4 carbon atoms is preferable, and 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 chain and cyclic aliphatic hydrocarbon groups, and divalent aliphatic hydrocarbon groups formed by combining them. The aliphatic hydrocarbon group 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 a monocyclic or polycyclic group. 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 , one of a chain type and a cyclic type, and an aliphatic hydrocarbon group formed by combining them are included. The aliphatic hydrocarbon group 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 ^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, pentyl group, hexyl group, perfluorohexyl group, A heptyl group, a perfluoro heptyl group, an octyl group, a perfluorooctyl group, etc. are mentioned.
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), A ^f11 is an ethylene group is preferred.
The aliphatic hydrocarbon group for A ^f13 is preferably an aliphatic hydrocarbon group having 1 to 6 carbon atoms, and more preferably an aliphatic hydrocarbon group having 2 to 3 carbon atoms.
The aliphatic hydrocarbon group for A ^f14 is preferably an aliphatic hydrocarbon group having 3 to 12 carbon atoms, and more preferably an aliphatic hydrocarbon group having 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.

As the structural unit represented by the formula (a4-2), structural units represented by the formula (a4-1-1) to the formula (a4-1-22) can be given.

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、−（ＣＨ₂）_j1−、−（ＣＨ₂）_j2−Ｏ−（ＣＨ₂）_j3−又は−（ＣＨ₂）_j4−ＣＯ−Ｏ−（ＣＨ₂）_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), A ^f21 is preferably — (CH ₂ ) _j1 —, more preferably an ethylene group or a methylene group, and still more preferably a methylene group.

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%.

［式（ａ５−１）中、
Ｒ⁵¹は、水素原子又はメチル基を表す。
Ｒ⁵²は、炭素数３〜１８の脂環式炭化水素基を表し、該脂環式炭化水素基に含まれる水素原子は炭素数１〜８の脂肪族炭化水素基又はヒドロキシ基で置換されていてもよい。但し、Ｌ⁵⁵との結合位置にある炭素原子に結合する水素原子は、炭素数１〜８の脂肪族炭化水素基で置換されない。
Ｌ⁵⁵は、単結合又は炭素数１〜１８の２価の飽和炭化水素基を表し、該飽和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に置き換わっていてもよい。］ <Structural unit (a5)>
Examples of the non-leaving hydrocarbon group that the structural unit (a5) has include a linear, branched, or cyclic hydrocarbon group. Especially, it is preferable that a structural unit (a5) is an alicyclic hydrocarbon group.
As a structural unit (a5), the structural unit represented by a formula (a5-1) is mentioned, for example.

[In the formula (a5-1),
R ⁵¹ represents a hydrogen atom or a methyl group.
R ⁵² represents an alicyclic hydrocarbon group having 3 to 18 carbon atoms, and a hydrogen atom contained in the alicyclic hydrocarbon group is substituted with an aliphatic hydrocarbon group or hydroxy group having 1 to 8 carbon atoms. May be. However, the hydrogen atom bonded to the carbon atom at the coupling position with the L ⁵⁵ is not substituted with an aliphatic hydrocarbon group having 1 to 8 carbon atoms.
L ⁵⁵ represents a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, a methylene group contained in the saturated hydrocarbon group may be replaced by an oxygen atom or a carbonyl group. ]

The alicyclic hydrocarbon group for R ⁵² may be monocyclic or polycyclic. Examples of the monocyclic alicyclic hydrocarbon group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group. Examples of the polycyclic alicyclic hydrocarbon group include an adamantyl group and a norbornyl group.
Examples of the aliphatic hydrocarbon group having 1 to 8 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, Examples thereof include alkyl groups such as octyl group and 2-ethylhexyl group.
Examples of the alicyclic hydrocarbon group having a substituent include a 3-hydroxyadamantyl group and a 3-methyladamantyl group.
R ⁵² is preferably an unsubstituted alicyclic hydrocarbon group having 3 to 18 carbon atoms, and more preferably an adamantyl group, a norbornyl group, or a cyclohexyl group.

Examples of the divalent saturated hydrocarbon group for L ⁵⁵ include a divalent aliphatic saturated hydrocarbon group and a divalent alicyclic saturated hydrocarbon group, preferably a divalent aliphatic saturated hydrocarbon group. .
Examples of the divalent aliphatic saturated hydrocarbon group include alkanediyl groups such as a methylene group, an ethylene group, a propanediyl group, a butanediyl group, and a pentanediyl group.
The divalent alicyclic saturated hydrocarbon group may be monocyclic or polycyclic. Examples of the monocyclic alicyclic saturated hydrocarbon group include cycloalkanediyl groups such as cyclopentanediyl group and cyclohexanediyl group. Examples of the polycyclic divalent alicyclic saturated hydrocarbon group include an adamantanediyl group and a norbornanediyl group.

式（Ｌ１−１）中、
Ｘ^x1は、カルボニルオキシ基又はオキシカルボニル基を表す。
Ｌ^x1は、炭素数１〜１６の２価の脂肪族飽和炭化水素基を表す。
Ｌ^x2は、単結合又は炭素数１〜１５の２価の脂肪族飽和炭化水素基を表す。
ただし、Ｌ^x1及びＬ^x2の合計炭素数は、１６以下である。
式（Ｌ１−２）中、
Ｌ^x3は、炭素数１〜１７の２価の脂肪族飽和炭化水素基を表す。
Ｌ^x4は、単結合又は炭素数１〜１６の２価の脂肪族飽和炭化水素基を表す。
ただし、Ｌ^x3及びＬ^x4の合計炭素数は、１７以下である。
式（Ｌ１−３）中、
Ｌ^x5は、炭素数１〜１５の２価の脂肪族飽和炭化水素基を表す。
Ｌ^x6及びＬ^x7は、それぞれ独立に、単結合又は炭素数１〜１４の２価の脂肪族飽和炭化水素基を表す。
ただし、Ｌ^x5、Ｌ^x6及びＬ^x7の合計炭素数は、１５以下である。
式（Ｌ１−４）中、
Ｌ^x8及びＬ^x9は、単結合又は炭素数１〜１２の２価の脂肪族飽和炭化水素基を表す。
Ｗ^x1は、炭素数３〜１５の２価の脂環式飽和炭化水素基を表す。
ただし、Ｌ^x8、Ｌ^x9及びＷ^x1の合計炭素数は、１５以下である。 Examples of the group in which the methylene group contained in the saturated hydrocarbon group is replaced with an oxygen atom or a carbonyl group include groups represented by formulas (L1-1) to (L1-4). In the following formula, * represents a bond with an oxygen atom.

In formula (L1-1),
X ^x1 represents a carbonyloxy group or an oxycarbonyl group.
L ^x1 represents a divalent aliphatic saturated hydrocarbon group having 1 to 16 carbon atoms.
L ^x2 represents a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 15 carbon atoms.
However, the total carbon number of L ^x1 and L ^x2 is 16 or less.
In formula (L1-2),
L ^x3 represents a divalent aliphatic saturated hydrocarbon group having 1 to 17 carbon atoms.
L ^x4 represents a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 16 carbon atoms.
However, the total carbon number of L ^x3 and L ^x4 is 17 or less.
In formula (L1-3),
L ^x5 represents a divalent aliphatic saturated hydrocarbon group having 1 to 15 carbon atoms.
L ^x6 and L ^x7 each independently represent a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 14 carbon atoms.
However, the total carbon number of L ^x5 , L ^x6 and L ^x7 is 15 or less.
In formula (L1-4),
L ^x8 and L ^x9 represent a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 12 carbon atoms.
W ^x1 represents a divalent alicyclic saturated hydrocarbon group having 3 to 15 carbon atoms.
However, the total carbon number of L ^x8 , L ^x9 and W ^x1 is 15 or less.

L ^x1 is preferably a C 1-8 divalent aliphatic saturated hydrocarbon group, more preferably a methylene group or an ethylene group.
L ^x2 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, more preferably a single bond.
L ^x3 is preferably a C 1-8 divalent aliphatic saturated hydrocarbon group.
L ^x4 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^x5 is preferably a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, more preferably a methylene group or an ethylene group.
L ^x6 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, more preferably a methylene group or an ethylene group.
L ^x7 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^x8 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, more preferably a single bond or a methylene group.
L ^x9 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, more preferably a single bond or a methylene group.
W ^x1 is preferably a C 3-10 divalent alicyclic saturated hydrocarbon group, more preferably a cyclohexanediyl group or an adamantanediyl group.

As group represented by a formula (L1-1), the bivalent group shown below is mentioned, for example.

As group represented by a formula (L1-2), the bivalent group shown below is mentioned, for example.

As group represented by a formula (L1-3), the bivalent group shown below is mentioned, for example.

As group represented by a formula (L1-4), the bivalent group shown below is mentioned, for example.

L ⁵⁵ is preferably a group represented by a single bond or the formula (L1-1).

式（ａ５−１−１）〜式（ａ５−１−１８）において、Ｒ⁵¹に相当するメチル基が水素原子に置き換わった構造単位も、構造単位（ａ５−１）の具体例として挙げることができる。 Examples of the structural unit (a5-1) include the following.

In the formula (a5-1-1) to the formula (a5-1-18), a structural unit in which a methyl group corresponding to R ⁵¹ is replaced with a hydrogen atom can also be given as specific examples of the structural unit (a5-1). it can.

  When the resin (A) has the structural unit (a5), the content is preferably 1 to 30 mol%, more preferably 2 to 20 mol%, based on all structural units of the resin (A). More preferred is ˜15 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), that is, a copolymer of the monomer (a1) and the monomer (s).
The structural unit (a1) is preferably at least one selected from 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) and a structural unit (a1-2) (preferably the structural unit having a cyclohexyl group or a cyclopentyl group).
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 selected from the structural unit represented by the formula (a3-1), the structural unit represented by the formula (a3-2), and the structural unit represented by the formula (a3-4). At least one kind.

  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 2,000 or more (more preferably 2,500 or more, more preferably 3,000 or more), 50,000 or less (more preferably 30,000 or less, further preferably 15,000 or less).
In this specification, the weight average molecular weight is a value determined by gel permeation chromatography. Gel permeation chromatography can be measured by the analytical conditions described in the examples.

<Resin (X)>
The resist composition of the present invention may contain a resin other than the resin (A). Examples of the resin other than the resin (A) include a resin composed only of the structural unit (s) and a resin including the structural unit (a4) (however, the structural unit (a1) is not included. There is). Of these, a resin containing the structural unit (a4) is preferable.
In the resin (X), the content of the structural unit (a4) is preferably 40 mol% or more, more preferably 45 mol% or more, and still more preferably 50 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 a structural unit derived from the structural unit (a2), the structural unit (a3), and other known monomers.
The weight average molecular weight of the resin (X) is preferably 6,000 or more (more preferably 7,000 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 contains the resin (X), the content thereof is preferably 1 to 60 parts by mass, more preferably 2 to 50 parts by mass with respect to 100 parts by mass of the resin (A). Preferably it is 2-40 mass parts, Most preferably, it is 3-30 mass parts.

80 mass% or more and 99 mass% or less are preferable with respect to solid content of a resist composition, and, as for the total content rate of resin other than resin (A) and resin (A), 90 mass% or more and 99 mass% or less are preferable. .
The solid content of the resist composition and the resin content relative thereto can be measured by a known analysis means such as liquid chromatography or gas chromatography.

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

  Examples of the solvent (E) 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 ethyl pyruvate Esters; ketones such as acetone, methyl isobutyl ketone, 2-heptanone and cyclohexanone; cyclic esters such as γ-butyrolactone; A solvent (E) may contain 2 or more types.

<Quencher (C)>
The quencher (C) includes a basic nitrogen-containing organic compound or a salt having a lower acidity than the acid generated from the salt (I) and the acid generator (B).
Examples of the basic nitrogen-containing organic compound include amines and ammonium salts. Examples of amines include aliphatic amines and aromatic amines. Aliphatic amines include primary amines, secondary amines and tertiary amines.

  As the quencher (C), 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, tripentylamine, tri Hexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, methyldibutylamine, methyldipentylamine, methyldihexyl Amine, methyldicyclohexylamine, methyldiheptylamine, methyldioctylamine, methyldinonylamine, methyldidecylamine, ethyldibutylamine, ethyldipentylamine, ethyldihexylamine, ethyldiheptylamine, ethyldioctylamine, ethyldinonylamine , Ethyldidecylamine, dicyclohexylmethylamine, tris [2- (2-methoxyethoxy) ethyl] amine, triisopropanolamine, ethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4′-diamino-1,2-diphenyl Ethane, 4,4′-diamino-3,3′-dimethyldiphenylmethane, 4,4′-diamino-3,3′-diethyldiphenylmethane, piperazine, morpholine, piperidine and Hindered amine compounds having a piperidine skeleton described in Japanese Utility Model Publication No. 11-52575, imidazole, 4-methylimidazole, pyridine, 4-methylpyridine, 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′-dipycolylamine, bipyridine and the like. Diisopropylaniline is preferable, and 2,6-diisopropylaniline is particularly preferable.

  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 acidity in the salt having a weaker acidity than the acid generated from the salt (I) and the acid generator (B) is represented by an acid dissociation constant (pKa). The salt having a lower acidity than the acid generated from the salt (I) and the acid generator (B) is a salt in which the acid dissociation constant of the acid generated from the salt is usually −3 <pKa, preferably −1. <PKa <7 salt, more preferably 0 <pKa <5 salt. Examples of the salt having weaker acidity than the acid generated from the acid generator (B) include a salt represented by the following formula, a weak acid inner salt represented by the formula (D), and JP 2012-229206 A: Examples thereof include salts described in JP 2012-6908 A, JP 2012-72109 A, JP 2011-39502 A, and JP 2011-191745 A. Preferably, it is a weak acid inner salt represented by the formula (D) (hereinafter sometimes referred to as “weak acid inner salt (D)”).

［式（Ｄ）中、
Ｒ^D1及びＲ^D2は、それぞれ独立に、炭素数１〜１２の１価の炭化水素基、炭素数１〜６のアルコキシ基、炭素数２〜７のアシル基、炭素数２〜７のアシルオキシ基、炭素数２〜７のアルコキシカルボニル基、ニトロ基又はハロゲン原子を表す。
ｍ’及びｎ’は、それぞれ独立に、０〜４の整数を表し、ｍ’が２以上の場合、複数のＲ^D1は同一又は相異なり、ｎ’が２以上の場合、複数のＲ^D2は同一又は相異なる。］

[In the formula (D),
R ^D1 and R ^D2 are each independently a monovalent hydrocarbon group having 1 to 12 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an acyl group having 2 to 7 carbon atoms, or an acyloxy group having 2 to 7 carbon atoms. Represents an alkoxycarbonyl group having 2 to 7 carbon atoms, a nitro group, or a halogen atom.
m ′ and n ′ each independently represents an integer of 0 to 4, and when m ′ is 2 or more, the plurality of R ^D1 are the same or different, and when n ′ is 2 or more, the plurality of R ^D2 are Same or different. ]

In the weak acid inner salt (D), the hydrocarbon groups of R ^D1 and R ^D2 include a monovalent aliphatic hydrocarbon group, a monovalent alicyclic hydrocarbon group, a monovalent aromatic hydrocarbon group, and Examples include groups formed by combining these.
Examples of the monovalent aliphatic hydrocarbon group include alkyl groups such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, t-butyl group, pentyl group, hexyl group, and nonyl group.
The monovalent alicyclic hydrocarbon group may be monocyclic or polycyclic, and may be either saturated or unsaturated. Examples thereof include cycloalkyl groups such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cyclononyl group, and cyclododecyl group, norbornyl group, adamantyl group, and the like.
Examples of the monovalent aromatic hydrocarbon group include phenyl groups, 1-naphthyl groups, 2-naphthyl groups, anthryl groups, biphenyl groups, and phenanthryl groups.
Examples of the group formed by combining these include an alkyl-cycloalkyl group, a cycloalkyl-alkyl group, an aralkyl group (for example, phenylmethyl group, 1-phenylethyl group, 2-phenylethyl group, 1-phenyl-1 -Propyl group, 1-phenyl-2-propyl group, 2-phenyl-2-propyl group, 3-phenyl-1-propyl group, 4-phenyl-1-butyl group, 5-phenyl-1-pentyl group, 6 Alkyl-aryl groups (for example, 2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 4-ethylphenyl group, 4-propylphenyl group, 4-phenyl-1-hexyl group, etc.) Isopropylphenyl group, 4-butylphenyl group, 4-t-butylphenyl group, 4-hexylphenyl group, 4-cyclohexyl Enyl group, tolyl group, xylyl group, cumenyl group, mesityl group, 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl group, etc.), aryl-cycloalkyl group, cycloalkyl-aryl group (for example, p -An adamantylphenyl group).

Examples of the alkoxy group include a methoxy group and an ethoxy group.
Examples of the acyl group include an acetyl group, a propanoyl group, a benzoyl group, and a cyclohexanecarbonyl group.
Examples of the acyloxy group include a group in which an oxy group (—O—) is bonded to the acyl group.
Examples of the alkoxycarbonyl group include a group in which a carbonyl group (—CO—) is bonded to the above alkoxy group.
Examples of the halogen atom include a fluorine atom, a chlorine atom, and a bromine atom.

In the formula (D), R ^D1 and R ^D2 each independently represent an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or 2 to 2 carbon atoms. Preferred are an acyl group having 4 carbon atoms, an acyloxy group having 2 to 4 carbon atoms, an alkoxycarbonyl group having 2 to 4 carbon atoms, a nitro group, or a halogen atom.
m ′ and n ′ are each independently preferably an integer of 0 to 2, and more preferably 0. When m ′ is 2 or more, the plurality of R ^D1 are the same or different, and when n ′ is 2 or more, the plurality of R ^D2 are the same or different.

Examples of the weak acid inner salt (D) include the following compounds.

  The content of the quencher (C) is preferably 0.01 to 5% by mass, more preferably 0.01 to 4% by mass, and particularly preferably 0.01 to 3% by mass in the solid content of the resist composition. % By mass.

<Other ingredients>
The resist composition may contain components other than those described above (hereinafter may be referred to as “other components (F)”) as necessary. As the other component (F), known additives in the resist field, such as a sensitizer, a dissolution inhibitor, a surfactant, a stabilizer, a dye, and the like can be used.

<Preparation of resist composition>
The resist composition includes resin (A) and salt (I), and if necessary, resins other than resin (A), acid generator (B), solvent (E), quencher (C) and other It can be prepared by mixing component (F). The mixing order is arbitrary and is not particularly limited. The temperature at the time of mixing can select an appropriate temperature from 10-40 degreeC according to the kind etc. of resin etc., the solubility with respect to solvents (E), 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., and the heating time is preferably 10 to 180 seconds. 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. 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 lasers 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 in the acid labile group. 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., and the development time is preferably 5 to 300 seconds. 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 a resist composition, 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 known as 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 a resist composition, 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.
As the organic developer, a developer containing butyl acetate and / or 2-heptanone is preferable. 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, It is suitable as a resist composition for an organic developer for ArF excimer laser exposure, and is useful for fine processing of semiconductors.

An example is given and it demonstrates still more concretely. In the examples, “%” and “parts” representing the content or amount used are based on mass unless otherwise specified.
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 H _XL -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)

  The structure of the compound was confirmed by measuring molecular peaks using mass spectrometry (LC: Agilent model 1100, MASS: Agilent LC / MSD model). In the following examples, the value of this molecular peak is indicated by “MASS”.

式（Ｉ−２−ａ）で表される化合物５０部、式（Ｉ−２−ｂ）で表される化合物１０．３３部及びクロロホルム３５０部を仕込み、２３℃で３０分間攪拌した。その後、酢酸銅（ＩＩ）０．２０部を仕込み、８０℃で２時間還流し、濃縮した。回収された濃縮物に、ｔｅｒｔ−ブチルメチルエーテル４４０部を加えて攪拌し、ろ過することにより、式（Ｉ−２−ｃ）で表される塩３２．９６部を得た。

Example 1: Synthesis of a salt represented by the formula (I-2)

50 parts of the compound represented by the formula (I-2-a), 10.33 parts of the compound represented by the formula (I-2-b) and 350 parts of chloroform were charged and stirred at 23 ° C. for 30 minutes. Thereafter, 0.20 part of copper (II) acetate was charged, refluxed at 80 ° C. for 2 hours, and concentrated. To the collected concentrate, 440 parts of tert-butyl methyl ether was added and stirred, followed by filtration to obtain 32.96 parts of the salt represented by the formula (I-2-c).

15.40 parts of the compound represented by the formula (I-2-d), 400 parts of chloroform, 200 parts of ion-exchanged water and 23.32 parts of the salt represented by the formula (I-2-c) were mixed. Stir at 18 ° C. for 18 hours and separate. To the collected organic layer, 86 parts of ion exchange water was added, stirred at 23 ° C. for 30 minutes, and separated to take out the organic layer. This washing operation was repeated three times. The obtained organic layer was concentrated, and 200 parts of tert-butyl methyl ether was added to the resulting residue and stirred, and the supernatant was removed. The obtained residue was concentrated to obtain 27.32 parts of the salt represented by the formula (I-2-e).

  14.76 parts of the compound represented by the formula (I-2-f), 59 parts of chloroform and 14.79 parts of the compound represented by the formula (I-2-g) were mixed and stirred at 60 ° C. for 1 hour. And cooled to 23 ° C. To the obtained reaction solution, 27.04 parts of the salt represented by the formula (I-2-e) was added, and the mixture was further stirred at 23 ° C. for 18 hours. To the resultant reaction mass, 235 parts of chloroform was added, 192 parts of a 2% aqueous oxalic acid solution was added, and the mixture was stirred at 23 ° C. for 30 minutes. Thereafter, the organic layer was separated by liquid separation. To the recovered organic layer, 70 parts of ion exchange water was added, stirred at 23 ° C. for 30 minutes, and separated to take out the organic layer. This washing operation was repeated 5 times. The obtained organic layer was concentrated, 30 parts of tert-butyl methyl ether was added to the resulting residue and stirred, and the supernatant was removed. The obtained residue was concentrated to obtain 22.28 parts of the salt represented by the formula (I-2).

MASS (ESI (+) Spectrum): M ⁺ 237.1
MASS (ESI (−) Spectrum): M ^- 383.1

式（Ｉ−２）で表される化合物１．９１部、式（Ｉ−４−ａ）で表される化合物０．７３部及び１，２−ジクロロエタン１０部を混合し、２３℃で３０分間攪拌した。得られた混合溶液に、ｐ−トルエンスルホン酸０．０１部を添加し、１００℃で３時間還流攪拌した。得られた反応物を２３℃まで冷却し、クロロホルム３０部及び５％炭酸水素ナトリウム水溶液１０部を加え、２３℃で３０分間攪拌した。その後、静置し、分液した。回収された有機層に、イオン交換水１０部を仕込み２３℃で３０分間攪拌し、分液することにより有機層を回収した。この水洗の操作を５回行った。得られた有機層を濃縮することにより、式（Ｉ−４）で表される化合物０．３９部を得た。 Example 2: Synthesis of a salt represented by the formula (I-4)

1.91 parts of the compound represented by the formula (I-2), 0.73 part of the compound represented by the formula (I-4-a) and 10 parts of 1,2-dichloroethane were mixed, and the mixture was mixed at 23 ° C. for 30 minutes. Stir. To the obtained mixed solution, 0.01 part of p-toluenesulfonic acid was added and stirred at 100 ° C. for 3 hours under reflux. The obtained reaction product was cooled to 23 ° C., 30 parts of chloroform and 10 parts of 5% aqueous sodium hydrogen carbonate solution were added, and the mixture was stirred at 23 ° C. for 30 minutes. Then, it left still and liquid-separated. To the recovered organic layer, 10 parts of ion-exchanged water was charged, stirred at 23 ° C. for 30 minutes, and separated to recover the organic layer. This washing operation was performed 5 times. The obtained organic layer was concentrated to obtain 0.39 parts of a compound represented by the formula (I-4).

MASS (ESI (+) Spectrum): M ⁺ 237.1
MASS (ESI (−) Spectrum): M ^- 527.1

Example 3: Synthesis of a salt represented by the formula (I-1)

  13.70 parts of the compound represented by the formula (I-1-f), 59 parts of chloroform and 14.79 parts of the compound represented by the formula (I-2-g) were mixed and stirred at 60 ° C. for 1 hour. And cooled to 23 ° C. To the obtained reaction solution, 27.04 parts of the salt represented by the formula (I-2-e) was added, and the mixture was further stirred at 23 ° C. for 18 hours. To the obtained mixture, 235 parts of chloroform was added, 192 parts of a 2% aqueous oxalic acid solution was added, and the mixture was stirred at 23 ° C. for 30 minutes. Thereafter, the organic layer was separated by liquid separation. To the recovered organic layer, 70 parts of ion exchange water was added, stirred at 23 ° C. for 30 minutes, and separated to take out the organic layer. This washing operation was repeated 5 times. The obtained organic layer was concentrated, 30 parts of tert-butyl methyl ether was added to the resulting residue and stirred, and the supernatant was removed. By concentrating the obtained residue, 24.31 parts of the salt represented by the formula (I-1) was obtained.

MASS (ESI (+) Spectrum): M ⁺ 237.1
MASS (ESI (-) Spectrum): M ^- 369.1

Example 4: Synthesis of salt represented by formula (I-3)

  14.92 parts of the compound represented by the formula (I-3-f), 59 parts of chloroform and 14.79 parts of the compound represented by the formula (I-2-g) were mixed and stirred at 60 ° C. for 1 hour. And cooled to 23 ° C. To the obtained reaction solution, 27.04 parts of the salt represented by the formula (I-2-e) was added, and the mixture was further stirred at 23 ° C. for 18 hours. To the obtained reaction mixture, 235 parts of chloroform was added, 192 parts of a 2% aqueous oxalic acid solution was added, and the mixture was stirred at 23 ° C. for 30 minutes. Thereafter, the organic layer was separated by liquid separation. To the recovered organic layer, 70 parts of ion exchange water was added, stirred at 23 ° C. for 30 minutes, and separated to take out the organic layer. This washing operation was repeated 5 times. The obtained organic layer was concentrated, 30 parts of tert-butyl methyl ether was added to the resulting residue and stirred, and the supernatant was removed. The obtained residue was concentrated to obtain 22.78 parts of the salt represented by the formula (I-3).

MASS (ESI (+) Spectrum): M ⁺ 237.1
MASS (ESI (-) Spectrum): M ^- 385.1

式（Ｉ−１０−ａ）で表される化合物４１．８４部、式（Ｉ−２−ｂ）で表される化合物１０．３３部及びクロロホルム３５０部を仕込み、２３℃で３０分間攪拌した。その後、酢酸銅（ＩＩ）０．２０部を仕込み、８０℃で２時間還流し、濃縮した。回収された濃縮物に、ｔｅｒｔ−ブチルメチルエーテル４４０部を加えて攪拌し、ろ過することにより、式（Ｉ−１０−ｃ）で表される塩２５．４４部を得た。 Example 5: Synthesis of salt represented by formula (I-10)

41.84 parts of the compound represented by the formula (I-10-a), 10.33 parts of the compound represented by the formula (I-2-b) and 350 parts of chloroform were charged and stirred at 23 ° C. for 30 minutes. Thereafter, 0.20 part of copper (II) acetate was charged, refluxed at 80 ° C. for 2 hours, and concentrated. To the collected concentrate, 440 parts of tert-butyl methyl ether was added and stirred, followed by filtration to obtain 25.44 parts of the salt represented by the formula (I-10-c).

式（Ｉ−２−ｄ）で表される化合物１５．４０部、クロロホルム４００部、イオン交換水２００部及び式（Ｉ−１０−ｃ）で表される塩２１．５７部を混合し、２３℃で１８時間攪拌し、分液した。回収された有機層に、イオン交換水８６部を加えて２３℃で３０分間攪拌し、分液して有機層を取り出した。この水洗操作を３回繰り返した。得られた有機層を濃縮し、得られた残渣に、ｔｅｒｔ−ブチルメチルエーテル２００部を加えて攪拌し、上澄液を除去した。得られた残渣を濃縮することにより、式（Ｉ−１０−ｅ）で表される塩２５．６８部を得た。

15.40 parts of the compound represented by the formula (I-2-d), 400 parts of chloroform, 200 parts of ion-exchanged water and 21.57 parts of the salt represented by the formula (I-10-c) were mixed, and 23 Stir at 18 ° C. for 18 hours and separate. To the collected organic layer, 86 parts of ion exchange water was added, stirred at 23 ° C. for 30 minutes, and separated to take out the organic layer. This washing operation was repeated three times. The obtained organic layer was concentrated, and 200 parts of tert-butyl methyl ether was added to the resulting residue and stirred, and the supernatant was removed. The obtained residue was concentrated to obtain 25.68 parts of the salt represented by the formula (I-10-e).

  14.76 parts of the compound represented by the formula (I-2-f), 59 parts of chloroform and 14.79 parts of the compound represented by the formula (I-2-g) were mixed and stirred at 60 ° C. for 1 hour. And cooled to 23 ° C. To the obtained reaction solution, 25.52 parts of the salt represented by the formula (I-10-e) was added, and the mixture was further stirred at 23 ° C. for 18 hours. To the obtained reaction mixture, 235 parts of chloroform was added, 192 parts of a 2% aqueous oxalic acid solution was added, and the mixture was stirred at 23 ° C. for 30 minutes. Thereafter, the organic layer was separated by liquid separation. To the recovered organic layer, 70 parts of ion exchange water was added, stirred at 23 ° C. for 30 minutes, and separated to take out the organic layer. This washing operation was repeated 5 times. The obtained organic layer was concentrated, 30 parts of tert-butyl methyl ether was added to the resulting residue and stirred, and the supernatant was removed. The obtained residue was concentrated to obtain 26.44 parts of the salt represented by the formula (I-10).

MASS (ESI (+) Spectrum): M ⁺ 211.1
MASS (ESI (−) Spectrum): M ^- 383.1

式（Ｉ−１０）で表される化合物１．８３部、式（Ｉ−４−ａ）で表される化合物０．７３部及び１，２−ジクロロエタン１０部を混合し、２３℃で３０分間攪拌した。得られた混合溶液に、ｐ−トルエンスルホン酸０．０１部を添加し、１００℃で３時間還流攪拌した。得られた反応物を２３℃まで冷却し、クロロホルム３０部及び５％炭酸水素ナトリウム水溶液１０部を加え、２３℃で３０分間攪拌した。その後、静置し、分液した。回収された有機層に、イオン交換水１０部を仕込み２３℃で３０分間攪拌し、分液することにより有機層を回収した。この水洗の操作を５回行った。得られた有機層を濃縮することにより、式（Ｉ−１０）で表される化合物０．５８部を得た。 Example 6: Synthesis of salt represented by formula (I-12)

1.83 parts of the compound represented by the formula (I-10), 0.73 part of the compound represented by the formula (I-4-a) and 10 parts of 1,2-dichloroethane are mixed and stirred at 23 ° C. for 30 minutes. Stir. To the obtained mixed solution, 0.01 part of p-toluenesulfonic acid was added and stirred at 100 ° C. for 3 hours under reflux. The obtained reaction product was cooled to 23 ° C., 30 parts of chloroform and 10 parts of 5% aqueous sodium hydrogen carbonate solution were added, and the mixture was stirred at 23 ° C. for 30 minutes. Then, it left still and liquid-separated. To the recovered organic layer, 10 parts of ion-exchanged water was charged, stirred at 23 ° C. for 30 minutes, and separated to recover the organic layer. This washing operation was performed 5 times. The obtained organic layer was concentrated to obtain 0.58 parts of a compound represented by the formula (I-10).

MASS (ESI (+) Spectrum): M ⁺ 211.1
MASS (ESI (−) Spectrum): M ^- 527.1

式（Ｉ−２−ｄ）で表される化合物１５．４０部、クロロホルム４００部、イオン交換水２００部及び式（ＩＸ−１−ａ）で表される塩１７．１９部を混合し、２３℃で１８時間攪拌し、分液した。回収された有機層に、イオン交換水１００部を加えて２３℃で３０分間攪拌し、分液して有機層を取り出した。この水洗操作を３回繰り返した。得られた有機層を濃縮し、得られた残渣に、ｔｅｒｔ−ブチルメチルエーテル１００部を加えて攪拌し、上澄液を除去した。得られた残渣を濃縮することにより、式（ＩＸ−１−ｂ）で表される塩２６．１８部を得た。

式（ＩＸ−１−ｃ）で表される化合物１３．７０部、クロロホルム５０部及び式（ＩＸ−１−ｄ）で表される化合物１４．７９部を混合し、６０℃で１時間攪拌し、２３℃に冷却した。得られた反応溶液に、式（ＩＸ−１−ｂ）で表される塩２６．１０部を添加し、さらに、２３℃で１８時間攪拌した。得られた反応混合物にクロロホルム２００部を添加し、２％シュウ酸水溶液１９２部を加えて２３℃で３０分間攪拌した。これを分液して有機層を取り出した。回収された有機層にイオン交換水７０部を加えて２３℃で３０分間攪拌し、分液して有機層を取り出した。この水洗操作を５回繰り返した。得られた有機層を濃縮し、得られた残渣にｔｅｒｔ−ブチルメチルエーテル３０部を加えて攪拌し、上澄液を除去した。得られた残渣を濃縮することにより、式（ＩＸ−１）で表される塩１９．４５部を得た。 Synthesis Example 1: Synthesis of salt represented by formula (IX-1)

15.40 parts of the compound represented by the formula (I-2-d), 400 parts of chloroform, 200 parts of ion-exchanged water and 17.19 parts of the salt represented by the formula (IX-1-a) were mixed, and 23 Stir at 18 ° C. for 18 hours and separate. To the collected organic layer, 100 parts of ion exchange water was added, stirred at 23 ° C. for 30 minutes, and separated to take out the organic layer. This washing operation was repeated three times. The obtained organic layer was concentrated, and 100 parts of tert-butyl methyl ether was added to the resulting residue and stirred, and the supernatant was removed. The obtained residue was concentrated to obtain 26.18 parts of the salt represented by the formula (IX-1-b).

13.70 parts of the compound represented by the formula (IX-1-c), 50 parts of chloroform and 14.79 parts of the compound represented by the formula (IX-1-d) were mixed and stirred at 60 ° C. for 1 hour. And cooled to 23 ° C. To the obtained reaction solution, 26.10 parts of the salt represented by the formula (IX-1-b) was added, and the mixture was further stirred at 23 ° C. for 18 hours. To the resulting reaction mixture, 200 parts of chloroform was added, 192 parts of a 2% oxalic acid aqueous solution was added, and the mixture was stirred at 23 ° C. for 30 minutes. This was separated and the organic layer was taken out. To the recovered organic layer, 70 parts of ion exchange water was added, stirred at 23 ° C. for 30 minutes, and separated to take out the organic layer. This washing operation was repeated 5 times. The obtained organic layer was concentrated, 30 parts of tert-butyl methyl ether was added to the resulting residue and stirred, and the supernatant was removed. The obtained residue was concentrated to obtain 19.45 parts of a salt represented by the formula (IX-1).

MASS (ESI (+) Spectrum): M ⁺ 221.1
MASS (ESI (-) Spectrum): M ^- 369.1

Synthesis Example 2 [Synthesis of salt represented by formula (B1-21)]

  30.00 parts of a compound represented by the formula (B1-21-b) obtained by the method described in JP-A-2008-209917, and a salt 35.50 represented by the formula (B1-21-a). Part, 100 parts of chloroform, and 50 parts of ion-exchanged water were stirred at 23 ° C. for 15 hours. Since the obtained reaction liquid was separated into two layers, the chloroform layer was separated and taken out, and 30 parts of ion-exchanged water was further added to the chloroform layer and washed with water. This operation was repeated 5 times. The chloroform layer was concentrated, 100 parts of tert-butyl methyl ether was added to the resulting residue, the mixture was stirred at 23 ° C. for 30 minutes, and filtered to give the salt represented by the formula (B1-21-c) 48. 57 parts were obtained.

式（Ｂ１−２１−ｃ）で表される塩２０．００部、式（Ｂ１−２１−ｄ）で表される化合物２．８４部及びモノクロロベンゼン２５０部を仕込み、２３℃で３０分間攪拌した。得られた混合液に、二安息香酸銅（ＩＩ）０．２１部を添加した。更に、これを１００℃で１時間攪拌した。得られた反応溶液を濃縮した。得られた残渣に、クロロホルム２００部及びイオン交換水５０部を加えて２３℃で３０分間攪拌し、分液して有機層を取り出した。回収された有機層にイオン交換水５０部を加えて２３℃で３０分間攪拌し、分液して有機層を取り出した。この水洗操作を５回繰り返した。得られた有機層を濃縮した。得られた残渣を、アセトニトリル５３．５１部に溶解し、濃縮した。その後、ｔｅｒｔ−ブチルメチルエーテル１１３．０５部を加えて攪拌し、ろ過することにより、式（Ｂ１−２１）で表される塩１０．４７部を得た。

20.00 parts of a salt represented by the formula (B1-21-c), 2.84 parts of a compound represented by the formula (B1-21-d) and 250 parts of monochlorobenzene were charged and stirred at 23 ° C. for 30 minutes. . 0.21 part of copper (II) dibenzoate was added to the obtained liquid mixture. Further, this was stirred at 100 ° C. for 1 hour. The resulting reaction solution was concentrated. To the obtained residue, 200 parts of chloroform and 50 parts of ion-exchanged water were added, stirred at 23 ° C. for 30 minutes, separated, and the organic layer was taken out. 50 parts of ion-exchanged water was added to the collected organic layer, and the mixture was stirred at 23 ° C. for 30 minutes and separated to take out the organic layer. This washing operation was repeated 5 times. The obtained organic layer was concentrated. The obtained residue was dissolved in 53.51 parts of acetonitrile and concentrated. Then, 113.05 parts of tert-butyl methyl ether was added and stirred, followed by filtration to obtain 10.47 parts of the salt represented by the formula (B1-21).

MASS (ESI (+) Spectrum): M ⁺ 237.1
MASS (ESI (−) Spectrum): M ^- 339.1

Synthesis Example 3 [Synthesis of Salt Represented by Formula (B1-22)]

  11.26 parts of a salt represented by the formula (B1-22-a), 10.00 parts of a compound represented by the formula (B1-22-b), 50 parts of chloroform and 25 parts of ion-exchanged water were charged at 23 ° C. For 15 hours. Since the obtained reaction liquid was separated into two layers, the chloroform layer was separated and taken out, and further 15 parts of ion exchange water was added to the chloroform layer and washed with water. This operation was repeated 5 times. The chloroform layer was concentrated, 50 parts of tert-butyl methyl ether was added to the resulting residue, and the mixture was stirred at 23 ° C. for 30 minutes and filtered to obtain the salt represented by the formula (B1-22-c) 11. 75 parts were obtained.

式（Ｂ１−２２−ｃ）で表される塩１１．７１部、式（Ｂ１−２２−ｄ）で表される化合物１．７０部及びモノクロロベンゼン４６．８４部を仕込み、２３℃で３０分間攪拌した。得られた混合液に、二安息香酸銅（ＩＩ）０．１２部を添加した。更に、１００℃で３０分間攪拌した。得られた反応溶液を濃縮した。得られた残渣に、クロロホルム５０部及びイオン交換水１２．５０部を加えて２３℃で３０分間攪拌し、分液して有機層を取り出した。回収された有機層にイオン交換水１２．５０部を加えて２３℃で３０分間攪拌し、分液して有機層を取り出した。この水洗操作を８回繰り返した。得られた有機層を濃縮した。得られた残渣に、ｔｅｒｔ−ブチルメチルエーテル５０部を加えて攪拌し、ろ過することにより、式（Ｂ１−２２）で表される塩６．８４部を得た。

11.71 parts of a salt represented by the formula (B1-22-c), 1.70 parts of a compound represented by the formula (B1-22-d) and 46.84 parts of monochlorobenzene were charged, and the mixture was charged at 23 ° C. for 30 minutes. Stir. To the obtained mixed solution, 0.12 part of copper (II) dibenzoate was added. Furthermore, it stirred at 100 degreeC for 30 minutes. The resulting reaction solution was concentrated. To the obtained residue, 50 parts of chloroform and 12.50 parts of ion-exchanged water were added, stirred at 23 ° C. for 30 minutes, and separated to take out the organic layer. 12.50 parts of ion-exchanged water was added to the collected organic layer, stirred at 23 ° C. for 30 minutes, and separated to take out the organic layer. This washing operation was repeated 8 times. The obtained organic layer was concentrated. To the obtained residue, 50 parts of tert-butyl methyl ether was added, stirred, and filtered to obtain 6.84 parts of the salt represented by the formula (B1-22).

MASS (ESI (+) Spectrum): M ⁺ 237.1
MASS (ESI (-) Spectrum): M ^- 323.0

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

Synthesis Example 4: Synthesis of Resin A1 As the monomer, monomer (a1-1-3), monomer (a1-2-9), monomer (a2-1-1) and monomer (a3-4-2) were used. The molar ratio [monomer (a1-1-3): monomer (a1-2-9): monomer (a2-1-1): monomer (a3-4-2)] is 45: 14: 2.5: 38. The resulting mixture was mixed with propylene glycol monomethyl ether acetate having a mass ratio of 1.5 times the total monomer amount to obtain a solution. To this solution, 1 mol% and 3 mol% of azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added to the total monomer amount, respectively, and these were heated at 73 ° C. for about 5 hours. did. The obtained reaction mixture was poured into a large amount of methanol / water mixed solvent to precipitate the resin, and this resin was filtered. The obtained resin was repulped in a methanol / water mixed solvent and filtered to obtain a resin A1 having a weight average molecular weight of 7.8 × 10 ^{3 in} a yield of 68%. This resin A1 has the following structural units.

Synthesis Example 5: Synthesis of Resin X1 Monomer (a4-1-7) was used as a monomer, and 1.2 mass times of methyl isobutyl ketone as a total monomer amount was added to obtain a solution. To this solution, 1 mol% and 3 mol% of azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added to the total monomer amount, respectively, and these were heated at 75 ° C. for about 5 hours. did. The obtained reaction mixture was poured into a large amount of methanol / water mixed solvent to precipitate the resin, and this resin was filtered. The obtained resin was repulped in a methanol / water mixed solvent and filtered to obtain Resin X-1 having a weight average molecular weight of 7.8 × 10 ^{3 in} a yield of 86%. This resin X1 has the following structural units.

Synthesis Example 6: Synthesis of Resin X2 Monomer (a4-0-12) was used as a monomer, and 1.5 mass times of methyl isobutyl ketone as a total monomer amount was added to prepare a solution. To this solution, 0.7 mol% and 2.1 mol% of azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile), respectively, as initiators were added with respect to the total monomer amount, and these were added at 75 ° C. Heated for about 5 hours. The obtained reaction mixture was poured into a large amount of a methanol / water mixed solvent to precipitate a resin, and this resin was filtered to obtain a resin X2 having a weight average molecular weight of 1.5 × 10 ^{4 in} a yield of 77%. This resin X2 has the following structural units.

Synthesis Example 7: Synthesis of Resin X3 Monomer (a5-1-1) and monomer (a4-0-12) were used as monomers, and the molar ratio [monomer (a5-1-1): monomer (a4-0-) 12)] was 50:50, and methyl isobutyl ketone 1.2 mass times the total monomer amount was added to obtain a solution. To this solution, 3 mol% of azobis (2,4-dimethylvaleronitrile) as an initiator was added based on the total amount of monomers, and heated at 70 ° C. for about 5 hours. The obtained reaction mixture was poured into a large amount of a methanol / water mixed solvent to precipitate a resin, and this resin was filtered to obtain a resin X3 having a weight average molecular weight of 1.0 × 10 ^{4 in} a yield of 91%. This resin X3 has the following structural units.

<Preparation of resist composition>
As shown in Table 1, the following components were mixed, and the resulting mixture was filtered through a fluororesin filter having a pore size of 0.2 μm to prepare a resist composition.

＜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 ２６５部
プロピレングリコールモノメチルエーテル ２０部
２−ヘプタノン ２０部
γ−ブチロラクトン ３．５部 <Resin>
A1, X1 to X3: Resin A1, Resin X1 to Resin X3
<Salt (I)>
I-2: salt represented by formula (I-2) I-4: salt represented by formula (I-4) I-1: salt represented by formula (I-1) I-3: formula Salt represented by (I-3) I-10: Salt represented by formula (I-10) I-12: Salt represented by formula (I-12) <Acid generator>
B1-21: salt represented by formula (B1-21) B1-22: salt represented by formula (B1-22) IX-1: salt represented by formula (IX-1) <Compound (D) >
D1: (Tokyo Chemical Industry Co., Ltd.)

<Solvent>
Propylene glycol monomethyl ether acetate 265 parts Propylene glycol monomethyl ether 20 parts 2-heptanone 20 parts γ-butyrolactone 3.5 parts

<Manufacture of resist pattern and its evaluation>
An organic antireflective coating composition [ARC-29; manufactured by Nissan Chemical Industries, Ltd.] was applied onto a 12-inch silicon wafer, and baked under the conditions of 205 ° C. and 60 seconds, whereby an organic layer having a thickness of 78 nm. An antireflection film was formed. Next, the resist composition was spin-coated on the organic antireflection film so that the film thickness of the composition layer after drying (pre-baking) was 85 nm. The silicon wafer coated with the resist composition was pre-baked on a direct hot plate at the temperature described in the “PB” column of Table 1 for 60 seconds to form a composition layer on the silicon wafer.
An ArF excimer laser stepper for immersion exposure [XT: 1900 Gi; manufactured by ASML, NA = 1.35, Dipole 0.900 / 0.700 Y-pol.] Is applied to the composition layer formed on the silicon wafer. Illumination], using a mask for forming a trench pattern (pitch 120 nm / trench 40 nm), the exposure was changed stepwise to perform exposure. Note that ultrapure water was used as the immersion medium. After the exposure, post-exposure baking was performed for 60 seconds on the hot plate at the temperature described in the “PEB” column of Table 1. Next, a negative resist pattern was manufactured by developing the heated composition layer using a butyl acetate (manufactured by Tokyo Chemical Industry Co., Ltd.) as a developing solution by a dynamic dispensing method at 23 ° C. for 20 seconds. .

  In the obtained resist pattern, the exposure amount at which the line width of the trench pattern was 40 nm was defined as effective sensitivity.

<Focus margin evaluation (DOF)>
A negative resist pattern was manufactured in the same manner as described above except that the exposure was performed while changing the focus stepwise in terms of effective sensitivity. In the obtained resist pattern, the focus range in which the width of the trench pattern is 40 nm ± 5% (38 to 42 nm) was defined as DOF (nm). The results are shown in Table 2.

  From the above results, it can be seen that the salt of the present invention, the acid generator, and the resist composition containing the same can form a pattern with a good focus margin.

  The salt, acid generator and resist composition of the present invention can form a pattern with a good focus margin and are useful for fine processing of semiconductors.

Claims (9)

A salt represented by the formula (I).

[In the formula (I),
R ¹ and R ² each independently represent a hydrogen atom, a hydroxy group or a hydrocarbon group having 1 to 12 carbon atoms, and —CH ₂ — contained in the hydrocarbon group is —O— or —CO—. It may be replaced.
m and n each independently represents 1 or 2. When m is 2, two R ¹ are the same or different, and when n is 2, two R ² are the same or different.
Ar represents an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent or a heteroaromatic hydrocarbon group having 5 to 36 carbon atoms which may have a substituent.
A ¹ represents a (1 + s) -valent aliphatic saturated hydrocarbon group having 1 to 18 carbon atoms which may have a hydroxy group, and —CH ₂ — contained in the aliphatic saturated hydrocarbon group is —O -Or -CO- may be substituted.
R ³ represents an alicyclic hydrocarbon group having 5 to 18 carbon atoms, and a hydrogen atom contained in the alicyclic hydrocarbon group may be substituted with a hydroxy group, or the alicyclic hydrocarbon group May be substituted with oxygen atoms, and the two oxygen atoms may form a ketal ring together with an alkanediyl group having 1 to 8 carbon atoms, and the ketal ring may contain a fluorine atom. The —CH ₂ — group contained in the alicyclic hydrocarbon group may be replaced by —O— or —CO—.
s represents an integer of 1 to 3. ] R ³ is an adamantyl group, and a hydrogen atom contained in the adamantyl group may be substituted with a hydroxy group, or two hydrogen atoms contained in the adamantyl group are each substituted with an oxygen atom, and the two oxygen atoms May form a ketal ring which may contain a fluorine atom together with an alkanediyl group having 1 to 8 carbon atoms, and the methylene group contained in the adamantyl group may be replaced by an oxygen atom or a carbonyl group A good salt according to claim 1.   The salt according to claim 1 or 2, wherein Ar is a phenyl group which may have a substituent. The salt according to any one of claims 1 to 3, wherein A ¹ is a (1 + s) -valent aliphatic saturated hydrocarbon group having 2 to 5 carbon atoms.   The acid generator containing the salt in any one of Claims 1-4.   A resist composition comprising the acid generator according to claim 5 and a resin containing a structural unit having an acid labile group.   The resist composition according to claim 6, comprising a salt having a lower acidity than an acid generated from the acid generator.   Furthermore, the resist composition of Claim 6 or 7 containing resin containing the structural unit which has a fluorine atom. (1) The process of apply | coating the resist composition in any one of Claims 6-8 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 method for producing a resist pattern, comprising: a step of heating the composition layer after exposure; and (5) a step of developing the composition layer after heating.