JP2011219459A - Salt and resist composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a salt for an acid-generating agent of a resist composition capable of producing patterns having an excellent resolution.SOLUTION: There are provided salts represented by formula (I) [wherein, Rand Rare each F or 1-6C perfluoroalkyl; Ris H or methyl; Xis a divalent 1-17C saturated hydrocarbon wherein the H included in the divalent hydrocarbon may be substituted with F and -CH- included in the divalent saturated hydrocarbon may be substituted with -O- or -CO-; Xis a 10-14C divalent aromatic hydrocarbon; Xis a single bond,-CO-O-or-CO-O-(CH)-CO-O-; and Zis an organic counter ion].

Description

  The present invention relates to a salt for an acid generator, a polymer having a structural unit derived from the salt, and a resist composition containing the salt and / or the polymer.

  Patent Document 1 describes triphenylsulfonium 2,4,6-triisopropylbenzenesulfonate and bis (cyclohexylsulfonium) diazomethane as salts for acid generators.

JP 2003-107708 A

  In the case of a conventional salt for an acid generator, the resolution of a resist pattern obtained from a resist composition containing the salt may not always be sufficiently satisfactory.

［式（Ｉ）中、
Ｒ^１及びＲ^２は、互いに独立に、フッ素原子又は炭素数１〜６のペルフルオロアルキル基を表す。
Ｒ^３は、水素原子又はメチル基を表す。
Ｘ^１は、２価の炭素数１〜１７の飽和炭化水素基を表し、前記２価の飽和炭化水素基に含まれる水素原子は、フッ素原子で置換されていてもよく、前記２価の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。
Ｘ^２は、炭素数１０〜１4の２価の芳香族炭化水素基を表す。
Ｘ^３は、単結合、^＊１−ＣＯ−Ｏ−^＊２又は^＊１−ＣＯ−Ｏ−（ＣＨ_２）_ｋ−ＣＯ−Ｏ−^＊２を表す。
＊１は−Ｃ（Ｒ^３）＝ＣＨ_２との結合手を表す。＊２はＸ^２との結合手を表す。
ｋは１〜６の整数を表す。
Ｚ^{１ ＋}は、有機対イオンを表す。］ 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 fluorine atom or a C 1-6 perfluoroalkyl group.
R ³ represents a hydrogen atom or a methyl group.
X ¹ represents a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, a hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with a fluorine atom, and the divalent saturated —CH ₂ — contained in the hydrocarbon group may be replaced by —O— or —CO—.
X ² represents a divalent aromatic hydrocarbon group having 10 to 14 carbon atoms.
X ³ represents a single bond, ^{* 1} —CO—O— ^{* 2} or ^{* 1} —CO—O— (CH ₂ ) _k —CO—O— ^{* 2} .
* 1 represents a bond with —C (R ³ ) ═CH ₂ . * 2 represents a bond to ^{X 2.}
k represents an integer of 1 to 6.
Z ^{1 +} represents an organic counter ion. ]

[2] X ¹ is ^{* 1} —CO—O— ^{* 2} (* 1 represents a bond with —C (R ¹ ) (R ² ) —, and * 2 represents a bond with X ² . The salt according to [1].

[3] The salt according to [1] or [2], wherein Z ^{1 +} is a triarylsulfonium cation.

[4] An acid generator containing the salt according to any one of [1] to [3] as an active ingredient.

[5] A polymer having a structural unit derived from the salt according to any one of [1] to [3].

[6] A resist composition comprising the acid generator according to [4] and a resin having an acid labile group and insoluble or hardly soluble in an aqueous alkali solution and soluble in an aqueous alkali solution by the action of an acid object.

[7] A resist composition comprising the polymer according to [5].

[8] The resist composition according to [6] or [7], further comprising a basic compound.

[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 using an exposure machine;
(4) A step of heating the composition layer after exposure,
(5) a step of developing the heated composition layer using a developing device;
A method for producing a resist pattern including:

  According to the salt of the present invention, a resist pattern having excellent resolution can be produced using a resist composition containing the salt.

<Salt represented by formula (I) (hereinafter sometimes referred to as “salt (I)”. The same applies to other symbols)>
The present invention is a salt represented by the above formula (I).
R ¹ and R ² each independently represents a fluorine atom or a C 1-6 perfluoroalkyl group. Examples of the perfluoroalkyl group include a perfluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group, a perfluorotert-butyl group, a perfluoropentyl group, and a perfluorohexyl group. . R ¹ and R ² are each independently preferably a perfluoromethyl group or a fluorine atom, more preferably a fluorine atom.
R ³ represents a hydrogen atom or a methyl group.

X ¹ represents a divalent saturated hydrocarbon group having 1 to 17 carbon atoms. Examples of the divalent saturated hydrocarbon group include a linear alkanediyl group, a branched alkanediyl group, and a cyclic saturated hydrocarbon group.
Examples of the linear alkanediyl group include a methylene group, an ethylene group, a propane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, and hexane-1,6-diyl. Group, heptane-1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group, dodecane-1 , 12-diyl group, tridecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, hexadecane-1,16-diyl group, heptadecane-1,17-diyl group Is mentioned.
Examples of the branched alkanediyl group include an alkyl group having 1 to 4 carbon atoms (for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group) to the linear alkanediyl group. , Tert-butyl group and the like).
Examples of the divalent cyclic saturated hydrocarbon group include a cycloalkanediyl group (for example, cyclohexanediyl group) and a divalent bridged cyclic hydrocarbon group (for example, adamantanediyl group).
X ¹ may be a combination of two or more of these groups.

-CH ₂ contained in a saturated hydrocarbon group of X ¹ - as has been replaced by -O- or -CO- group, for example, the formula ^(X 1 -1) ~ Formula ^(X 1 -6) and the like. X ¹ is preferably any of formula (X ¹ -1) to formula (X ¹ -4), more preferably formula (X ¹ -1) or formula (X ¹ -2). Incidentally, the formula ^(X 1 -1) ~ Formula ^(X 1 -6) is a left side ^{C (R 1) (R 2} ) - bond and. The same applies to specific examples of the following formulas (X ¹ -1) to (X ¹ -6).

式（Ｘ^１−１）〜式（Ｘ^１−６）中、
Ｘ^１１は、単結合又は炭素数１〜１５の飽和炭化水素基を表す。
Ｘ^１２は、単結合又は炭素数１〜１２の飽和炭化水素基を表す。
Ｘ^１３は、炭素数１〜１３の飽和炭化水素基を表す。
Ｘ^１４は、炭素数１〜１５の飽和炭化水素基を表す。
Ｘ^１５及びＸ^１６は、それぞれ独立に、炭素数１〜１５の飽和炭化水素基を表す。
Ｘ^１７は、炭素数１〜１４の飽和炭化水素基を表す。
Ｘ^１８及びＸ^１９は、それぞれ独立に、炭素数１〜１１の飽和炭化水素基を表す。
中でも、式（Ｘ^１−１）で表される２価の基が好ましく、Ｘ^１１が単結合又は−ＣＨ_２−である式（Ｘ^１−１）で表される２価の基がより好ましい。

In the formula (X ¹ -1) to the formula (X ¹ -6),
X ¹¹ represents a single bond or a saturated hydrocarbon group having 1 to 15 carbon atoms.
X ¹² represents a single bond or a saturated hydrocarbon group having 1 to 12 carbon atoms.
X ¹³ represents a saturated hydrocarbon group having 1 to 13 carbon atoms.
X ¹⁴ represents a saturated hydrocarbon group having 1 to 15 carbon atoms.
X ¹⁵ and X ¹⁶ each independently represent a saturated hydrocarbon group having 1 to 15 carbon atoms.
X ¹⁷ represents a saturated hydrocarbon group having 1 to 14 carbon atoms.
X ¹⁸ and X ¹⁹ each independently represent a saturated hydrocarbon group having 1 to 11 carbon atoms.
Among them, preferred are a divalent group represented by the formula ^(X 1 ^-1), X ¹¹ is a single bond or -CH ₂ - divalent group is more preferably represented by the formula ^(X 1 -1) is .

Examples of the divalent group represented by the formula (X ¹ -1) include the following.

Examples of the divalent group represented by the formula (X ¹ -2) include the following.

Examples of the divalent group represented by the formula (X ¹ -3) include the following.

Examples of the divalent group represented by the formula (X ¹ -4) include the following.

Examples of the divalent group represented by the formula (X ¹ -5) include the following.

Examples of the divalent group represented by the formula (X 1 ^-6), for example, include the following.

A hydrogen atom contained in the saturated hydrocarbon group for X ¹ may be substituted with a fluorine atom.

Examples of the divalent aromatic hydrocarbon group having 10 to 14 carbon atoms in X ² include the following groups. However, * represents a bond in the following groups.

X ³ includes a single bond, ^{* 1} —CO—O— ^{* 2} , ^{* 1} —CO—O—CH ₂ —CO—O— ^{* 2} , ^{* 1} —CO—O— (CH ₂ ) ₂ —CO—. _{^{O- * 2, * 1 -CO-}} O- (CH 2) 3 -CO-O- * 2, * 1 -CO-O- (CH 2) 4 -CO-O- * 2, * 1 -CO- O— (CH ₂ ) ₅ —CO—O— ^{* 2} and ^{* 1} —CO—O— (CH ₂ ) ₆ —CO—O— ^{* 2} (* represents a bond to X ² ). , A single bond, ^{* 1} —CO—O— ^{* 2} or ^{* 1} —CO—O—CH ₂ —CO—O— ^{* 2} is preferable, and a single bond or ^{* 1} —CO—O— ^* is more preferable.

Examples of the salt represented by the formula (I) include the following salts.

Examples of Z ¹⁺ include onium cations such as sulfonium cations, iodonium cations, ammonium cations, benzothiazolium cations, and phosphonium cations. Among these, a sulfonium cation and an iodonium cation are preferable, and an arylsulfonium cation is more preferable.

Z ¹⁺ is preferably represented by any one of formulas (b2-1) to (b2-4).

In these formulas (b2-1) to (b2-4),
R ^{b4 to} R ^b6 each independently represent an aliphatic hydrocarbon group having 1 to 30 carbon atoms, a saturated cyclic hydrocarbon group having 3 to 18 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms. The aliphatic hydrocarbon group may be substituted with a hydroxy group, an alkoxy group having 1 to 12 carbon atoms or an aromatic hydrocarbon group having 6 to 18 carbon atoms, and the saturated cyclic hydrocarbon group includes a halogen atom, It may be substituted with an acyl group having 2 to 4 carbon atoms or a glycidyloxy group, and the aromatic hydrocarbon group is a halogen atom, a hydroxy group, an aliphatic hydrocarbon group having 1 to 18 carbon atoms, or 3 to 3 carbon atoms. It may be substituted with an 18 saturated cyclic hydrocarbon group or an alkoxy group having 1 to 12 carbon atoms.

R ^b7 and R ^b8 each independently represent a hydroxy group, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.
m2 and n2 each independently represent an integer of 0 to 5.

R ^b9 and R ^b10 each independently represent an aliphatic hydrocarbon group having 1 to 18 carbon atoms or a saturated cyclic hydrocarbon group having 3 to 18 carbon atoms.
R ^b11 represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 18 carbon atoms, a saturated cyclic hydrocarbon group having 3 to 18 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms.
The aliphatic hydrocarbon group of R ^{b9 to} R ^b11 preferably has 1 to 12 carbon atoms, and the saturated cyclic hydrocarbon group preferably has 3 to 18 carbon atoms, more preferably 4 to 12 carbon atoms.
R ^b12 represents an aliphatic hydrocarbon group having 1 to 12 carbon atoms, a saturated cyclic hydrocarbon group having 3 to 18 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms. The aromatic hydrocarbon group is an aliphatic hydrocarbon group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, a saturated cyclic hydrocarbon group having 3 to 18 carbon atoms, or an alkylcarbonyloxy having 1 to 12 carbon atoms. It may be substituted with a group.
R ^b9 and R ^b10 , and R ^b11 and R ^b12 may be independently bonded to each other to form a 3- to 12-membered ring (preferably a 3- to 7-membered ring), These rings —CH ₂ — may be replaced by —O—, —S— or —CO—.

R ^{b13 to} R ^b18 each independently represent a hydroxy group, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.
L ^b11 represents -S- or -O-.
o2, p2, s2, and t2 each independently represents an integer of 0 to 5.
q2 and r2 each independently represents an integer of 0 to 4.
u2 represents 0 or 1.
When any of o2 to t2 is 2, any of the plurality of R ^{b13 to} R ^b18 may be the same as or different from each other.

  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.

Preferred aliphatic hydrocarbon groups are methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, hexyl, octyl and 2-ethylhexyl. It is.
Preferred saturated cyclic hydrocarbon groups are cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclodecyl group, 2-alkyl-2-adamantyl group, 1- (1-adamantyl) -1-alkyl group, And an isobornyl group.
Preferred aromatic hydrocarbon groups are phenyl group, 4-methylphenyl group, 4-ethylphenyl group, 4-tert-butylphenyl group, 4-cyclohexylphenyl group, 4-methoxyphenyl group, biphenylyl group, naphthyl group. It is.
Examples of the aliphatic hydrocarbon group (aralkyl group) whose substituent is an aromatic hydrocarbon group include a benzyl group.
Examples of the ring formed by R ^b9 and R ^b10 include a thiolane-1-ium ring (tetrahydrothiophenium ring), a thian-1-ium ring, and a 1,4-oxathian-4-ium ring.
^Examples of the ring formed by R ^b11 and R ^b12 include an oxocycloheptane ring, an oxocyclohexane ring, an oxonorbornane ring, and an oxoadamantane ring.

  Among the cations (b2-1) to (b2-4), the cation (b2-1) is preferable, the cation represented by the formula (b2-1-1) is more preferable, and the triphenylsulfonium cation (formula (b2) In (1-1), v2 = w2 = x2 = 0) is more preferable.

式（ｂ２−１−１）中、
Ｒ^b19〜Ｒ^b21は、それぞれ独立に、ハロゲン原子（より好ましくはフッ素原子）、ヒドロキシ基、炭素数１〜１８の脂肪族炭化水素基、炭素数３〜１８の飽和環状炭化水素基又は炭素数１〜１２のアルコキシ基を表す。
脂肪族炭化水素基は、好ましくは炭素数１〜１２であり、飽和環状炭化水素基は、好ましくは炭素数４〜１８である。
前記脂肪族炭化水素基は、ヒドロキシ基、炭素数１〜１２のアルコキシ基又は炭素数６〜１８の芳香族炭化水素基で置換されていてもよい。
前記飽和環状炭化水素基は、ハロゲン原子、炭素数２〜４のアシル基又はグリシジルオキシ基で置換されていてもよい。
ｖ２〜ｘ２は、それぞれ独立に０〜５の整数（好ましくは０又は１）を表す。ｖ２〜ｘ２のいずれかが２以上のとき、それぞれ、複数のＲ^b19〜Ｒ^b21のいずれかは、互いに同一でも異なってもよい。
なかでも、Ｒ^b19〜Ｒ^b21は、それぞれ独立に、好ましくは、ハロゲン原子（より好ましくはフッ素原子）、ヒドロキシ基、炭素数１〜１２のアルキル基、又は炭素数１〜１２のアルコキシ基である。

In formula (b2-1-1),
R ^{b19 to} R ^b21 each independently represent a halogen atom (more preferably a fluorine atom), a hydroxy group, an aliphatic hydrocarbon group having 1 to 18 carbon atoms, a saturated cyclic hydrocarbon group having 3 to 18 carbon atoms, or a carbon number. 1 to 12 alkoxy groups are represented.
The aliphatic hydrocarbon group preferably has 1 to 12 carbon atoms, and the saturated cyclic hydrocarbon group preferably has 4 to 18 carbon atoms.
The aliphatic hydrocarbon group may be substituted with a hydroxy group, an alkoxy group having 1 to 12 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms.
The saturated cyclic hydrocarbon group may be substituted with a halogen atom, an acyl group having 2 to 4 carbon atoms, or a glycidyloxy group.
v2 to x2 each independently represents an integer of 0 to 5 (preferably 0 or 1). When any one of v2 to x2 is 2 or more, any one of the plurality of R ^{b19 to} R ^b21 may be the same as or different from each other.
Among them, R ^{b19 to} R ^b21 are preferably each independently a halogen atom (more preferably a fluorine atom), a hydroxy group, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. .

Specific examples of the cation (b2-1-1) include the following.

Specific examples of the cation (b2-2) include the following.

Specific examples of the cation (b2-3) include the following.

Specific examples of the cation (b2-4) include the following.

  The salt represented by the formula (I) is a combination of the above-mentioned anions and cations. Although the above-mentioned anion and cation can be combined arbitrarily, the salt represented below is preferable.

［式中、Ｒ^b19〜Ｒ^b21、ｖ２〜ｘ２は前記と同じ意味を表す。］

[ ^Wherein , R ^{b19 to} R ^b21 and v2 to x2 represent the same meaning as described above. ]

Furthermore, the following salts are more preferable.

式（ＩＡ−２）で表される化合物としては、４−メタクリロイルオキシ−１−ナフトール、５−メタクリロイルオキシ−１−ナフトール、４−ヒドロキシ−１−ビニルナフタレン、２−ヒドロキシ−６−ビニルナフタレンなどが挙げられる。 Salt represented by the formula (I) are, for example, ^{X 1} is the formula ^(X 1 -1), a group represented by ^{(-CO-O-X 11 -} ) ^{a, X 11} is a single bond formula ( The salt represented by IA) can be obtained by reacting the salt represented by the formula (IA-1) and the compound represented by the formula (IA-2) in a solvent. Examples of the solvent include acetonitrile.

Examples of the compound represented by the formula (IA-2) include 4-methacryloyloxy-1-naphthol, 5-methacryloyloxy-1-naphthol, 4-hydroxy-1-vinylnaphthalene, 2-hydroxy-6-vinylnaphthalene and the like. Is mentioned.

A salt represented by the formula (IA-1) is obtained by reacting a salt represented by the formula (IA-3) and a compound represented by the formula (IA-4) (carbonyldiimidazole) in a solvent. Can be manufactured. Examples of the solvent include acetonitrile.
The salt represented by the formula (IA-3) can be synthesized by the method described in JP-A-2008-127367.

式（ＩＢ−２）で表される化合物としては、４−メタクリロイルオキシ−１−ナフトール、５−メタクリロイルオキシ−１−ナフトール、４−ヒドロキシ−１−ビニルナフタレン、２−ヒドロキシ−６−ビニルナフタレンなどが挙げられる。 For example, X ¹ is a group represented by the formula (X ¹ -2) (—CO—O—X ¹³ —CO—O—X ¹² —), and X ¹² is a single bond represented by the formula (IB). The salt obtained can be obtained by reacting the salt represented by the formula (IB-1) and the compound represented by the formula (IB-2) in a solvent. Examples of the solvent include acetonitrile.

Examples of the compound represented by the formula (IB-2) include 4-methacryloyloxy-1-naphthol, 5-methacryloyloxy-1-naphthol, 4-hydroxy-1-vinylnaphthalene, 2-hydroxy-6-vinylnaphthalene and the like. Is mentioned.

The salt represented by the formula (IB-1) is obtained by, for example, reacting a salt represented by the formula (IB-3) with a compound represented by the formula (IB-4) (carbonyldiimidazole) in a solvent. Can be manufactured. Examples of the solvent include acetonitrile.

式（ＩＢ−５）で表される塩は、特開２００８−１２７３６７号公報に記載された方法で合成することができる。
式（ＩＢ−６）で表される化合物としては、ブロモ酢酸等が挙げられる。 The salt represented by the formula (IB-3) can be obtained by reacting the salt represented by the formula (IB-5) with the compound represented by the formula (IB-6) in the presence of a catalyst. Here, examples of the catalyst include potassium iodide and potassium carbonate. Examples of the solvent include dimethylformamide.

The salt represented by the formula (IB-5) can be synthesized by the method described in JP-A-2008-127367.
Examples of the compound represented by the formula (IB-6) include bromoacetic acid.

  The acid generator of the present invention contains a salt represented by the formula (I). When used as an acid generator, the salt represented by the formula (I) may be used alone or in combination of two or more.

<Polymer (D)>
The polymer of the present invention is a polymer containing a structural unit derived from the salt represented by the formula (I).
The polymer of the present invention may contain a structural unit derived from a monomer different from the salt represented by the formula (I).
When the polymer includes a structural unit derived from a monomer different from the salt represented by the formula (I), the content of the structural unit derived from the salt represented by the formula (I) in the polymer is In all the units, it is usually 1 to 30 mol%, preferably 2 to 20 mol%, more preferably 3 to 10 mol%.
A monomer different from the salt represented by the formula (I) will be described below.

  The polymer is preferably a polymer that becomes alkali-soluble by the action of an acid. A polymer that becomes alkali-soluble by the action of an acid can be produced by polymerizing a monomer having an acid-labile group (hereinafter sometimes referred to as “monomer having an acid-labile group (a1)”). It becomes alkali-soluble by the action of acid. The phrase “becomes soluble in an alkali by the action of an acid” means “being insoluble or hardly soluble in an alkaline aqueous solution before contact with an acid, but soluble in an alkaline aqueous solution after contact with an acid”. . As the monomer (a1) having an acid labile group, one type may be used alone, or two or more types may be used in combination.

<Monomer (a1) having an acid labile group>
The term “acid-labile group” means a group that cleaves a leaving group upon contact with an acid to form a hydrophilic group (for example, a hydroxy group or a carboxy group). Examples of the acid labile group include an alkoxycarbonyl group represented by the formula (1) in which —O— is bonded to a tertiary carbon atom (excluding a bridgehead carbon atom of a bridged cyclic hydrocarbon group) (ie, An ester bond having a tertiary alcohol residue). Hereinafter, the group represented by the formula (1) may be referred to as “acid-labile group (1)”.

式（１）中、Ｒ^a1〜Ｒ^a3は、それぞれ独立に、炭素数１〜８の脂肪族炭化水素基又は炭素数３〜２０の飽和環状炭化水素基を表すか或いはＲ^a1及びＲ^a2は互いに結合して炭素数３〜２０の環を形成する。＊は結合手を表す（以下同じ）。

In the formula (1), R ^{a1 to} R ^a3 each independently represent an aliphatic hydrocarbon group having 1 to 8 carbon atoms or a saturated cyclic hydrocarbon group having 3 to 20 carbon atoms, or R ^a1 and R ^a2 are Bond to each other to form a ring having 3 to 20 carbon atoms. * Represents a bond (same below).

式（１）では、飽和環状炭化水素基の炭素数は、好ましくは炭素数１〜１６である。 Examples of the aliphatic hydrocarbon group include an alkyl group, and examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, and an octyl group.
The saturated cyclic hydrocarbon group may be monocyclic or polycyclic, for example, a cycloalkyl group (for example, a cyclopentyl group, a cyclohexyl group, a methylcyclohexyl group, a dimethylcyclohexyl group, a cycloheptyl group, Monocyclic saturated cyclic hydrocarbon groups such as cyclooctyl groups; groups obtained by hydrogenating condensed aromatic hydrocarbon groups (for example, hydronaphthyl groups), bridged cyclic hydrocarbon groups (for example, adamantyl groups, norbornyl) Group, methyl norbornyl group) and the like. Further, a group in which a bridging ring (for example, norbornane ring) and a single ring (for example, cycloheptane ring, cyclohexane ring) or polycyclic (for example, decahydronaphthalene ring) or a bridging ring are condensed as described below. Groups; groups in which these are combined (methylcyclohexyl group, dimethylcyclohexyl group, methylnorbornyl group) and the like.

In the formula (1), the saturated cyclic hydrocarbon group preferably has 1 to 16 carbon atoms.

Examples of the ring formed by combining R ^a1 and R ^a2 with each other include a saturated cyclic hydrocarbon group and an aromatic hydrocarbon group. The number of carbon atoms in the ring is preferably 3 to 12 carbon atoms.

Examples of the acid labile group (1) include a 1,1-dialkylalkoxycarbonyl group (in the group (1), R ^{a1 to} R ^a3 are alkyl groups, preferably a tert-butoxycarbonyl group), 2-alkyl-2-adamantyloxycarbonyl group (in the formula (1), R ^a1 , R ^a2 and a carbon atom form an adamantyl group, and R ^a3 is an alkyl group) and 1- (1-adamantyl)- 1-alkylalkoxycarbonyl groups (in the formula (1), R ^a1 and R ^a2 are alkyl groups and R ^a3 is an adamantyl group) and the like.

  The monomer (a1) having an acid labile group is preferably a monomer having an acid labile group (1) and a carbon-carbon double bond, more preferably an acid labile group (1). (Meth) acrylic monomer having

  Among the (meth) acrylic monomers having the acid-labile group (1), those having a saturated cyclic hydrocarbon group having 5 to 20 carbon atoms are preferred. If a polymer obtained by polymerizing the monomer (a1) having a bulky structure such as a saturated cyclic hydrocarbon group is used, the resolution of the resist can be improved.

  Among the (meth) acrylic monomers having the acid labile group (1) and the saturated cyclic hydrocarbon group, the acid labile group represented by the formula (a1-1) or the formula (a1-2) Monomers having are preferred. These may be used alone or in combination of two or more.

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−を表す。
ｋ１は１〜７の整数を表す。＊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の脂肪族炭化水素基又は炭素数３〜１０の飽和環状炭化水素基を表す。
ｍ１は０〜１４の整数を表す。
ｎ１は０〜１０の整数を表す。

In formula (a1-1) and formula (a1-2),
L ^a1 and L ^a2 each independently represent —O— or ^* —O— (CH ₂ ) _k1 —CO—O—.
k1 represents an integer of 1 to 7. * Represents a bond with -CO-.
R ^a4 and R ^a5 each independently represent a hydrogen atom or a methyl group.
R ^a6 and R ^a7 each independently represent an aliphatic hydrocarbon group having 1 to 8 carbon atoms or a saturated cyclic hydrocarbon group having 3 to 10 carbon atoms.
m1 represents the integer of 0-14.
n1 represents an integer of 0 to 10.

In the formula (a1-1) and the formula (a1-2), L ^a1 and L ^a2 are preferably, -O- or _{-O- (CH 2) f1 -CO-} O- and is (wherein f1 is 1 to 4), and more preferably -O-.
R ^a4 and R ^a5 are preferably methyl groups.
The aliphatic hydrocarbon group represented by R ^a6 and R ^a7 preferably has 6 or less carbon atoms. The saturated cyclic hydrocarbon group preferably has 8 or less carbon atoms, more preferably 6 or less.
m1 is preferably an integer of 0 to 3, more preferably 0 or 1.
n1 is preferably an integer of 0 to 3, more preferably 0 or 1.
k1 is preferably an integer of 1 to 4, more preferably 1.

  As a monomer (a1-1) which has an adamantyl group, the following are mentioned, for example. Among them, 2-methyl-2-adamantyl (meth) acrylate, 2-ethyl-2-adamantyl (meth) acrylate and 2-isopropyl-2-adamantyl (meth) acrylate are preferable, and those in the form of methacrylate are more preferable.

  As a monomer (a1-2) which has a cyclohexyl group, the following are mentioned, for example. Among these, 1-ethyl-1-cyclohexyl (meth) acrylate is preferable, and 1-ethyl-1-cyclohexyl methacrylate is more preferable.

  Content of the structural unit derived from the monomer represented by the formula (a1-1) or the formula (a1-2) in the polymer is usually 10 to 95 mol%, preferably 15 in all units of the polymer. It is -90 mol%, More preferably, it is 20-85 mol%.

  Examples of the monomer having an acid labile group (1) and a carbon-carbon double bond include a monomer having a norbornene ring represented by the formula (a1-3). Since the polymer having a structural unit derived from the monomer represented by the formula (a1-3) having an acid labile group has a bulky structure, the resolution of the resist can be improved. Furthermore, the monomer represented by the formula (a1-3) having an acid-labile group can improve the resistance to dry etching of a resist by introducing a rigid norbornane ring into the main chain of the polymer.

式（ａ１−３）中、
Ｒ^a9は、水素原子、置換基（例えば、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、シアノ基又は炭素数１〜８のアルコキシカルボニル基（−ＣＯＯＲ^a13）を表し、Ｒ^a13は、炭素数１〜８の脂肪族炭化水素基又は炭素数３〜８の飽和環状炭化水素基を表し、前記脂肪族炭化水素基及び前記飽和環状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、前記脂肪族炭化水素基及び前記飽和環状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^a10〜Ｒ^a12は、それぞれ独立に、炭素数１〜１２の脂肪族炭化水素基又は炭素数３〜１２の飽和環状炭化水素基を表すか、或いはＲ^a10及びＲ^a11は互いに結合して炭素数３〜２０の環を形成し、前記脂肪族炭化水素基及び前記飽和環状炭化水素基の水素原子はヒドロキシ基等で置換されていてもよく、前記脂肪族炭化水素基及び前記飽和環状炭化水素基の−ＣＨ_２−は−Ｏ−又は−ＣＯ−で置き換わっていてもよい。

In formula (a1-3),
R ^a9 is a hydrogen atom, an aliphatic hydrocarbon group having 1 to 3 carbon atoms, a carboxy group, a cyano group, or an alkoxycarbonyl group having 1 to 8 carbon atoms (which may have a substituent (for example, a hydroxy group) ( -COOR ^a13 ), R ^a13 represents an aliphatic hydrocarbon group having 1 to 8 carbon atoms or a saturated cyclic hydrocarbon group having 3 to 8 carbon atoms, and the aliphatic hydrocarbon group and the saturated cyclic hydrocarbon group. The hydrogen atom contained in may be substituted with a hydroxy group, and —CH ₂ — contained in the aliphatic hydrocarbon group and the saturated cyclic hydrocarbon group may be replaced with —O— or —CO—. .
R ^{a10 to} R ^a12 each independently represents an aliphatic hydrocarbon group having 1 to 12 carbon atoms or a saturated cyclic hydrocarbon group having 3 to 12 carbon atoms, or R ^a10 and R ^a11 are bonded to each other to form carbon. A ring of formula 3 to 20 is formed, and a hydrogen atom of the aliphatic hydrocarbon group and the saturated cyclic hydrocarbon group may be substituted with a hydroxy group or the like, and the aliphatic hydrocarbon group and the saturated cyclic hydrocarbon The group —CH ₂ — may be replaced by —O— or —CO—.

  Here, examples of the alkoxycarbonyl group include groups in which a carbonyl group is bonded to an alkoxy group such as a methoxycarbonyl group or an ethoxycarbonyl group.

Examples of the aliphatic hydrocarbon group which may have a substituent for R ^a9 include a methyl group, an ethyl group, a propyl group, a hydroxymethyl group, and a 2-hydroxyethyl group.
^Examples of R ^a13 include a methyl group, an ethyl group, a propyl group, a 2-oxo-oxolan-3-yl group, and a 2-oxo-oxolan-4-yl group.
Examples of R ^{a10 to} R ^a12 include a methyl group, an ethyl group, a cyclohexyl group, a methylcyclohexyl group, a hydroxycyclohexyl group, an oxocyclohexyl group, and an adamantyl group.
Examples of the ring formed by R ^a10 , R ^a11 and the carbon to which they are bonded include saturated cyclic hydrocarbon groups, and specific examples include a cyclohexyl group and an adamantyl group.

  Examples of the monomer (a1-3) having a norbornene ring include, for example, 5-norbornene-2-carboxylic acid-tert-butyl, 5-norbornene-2-carboxylic acid 1-cyclohexyl-1-methylethyl, 5-norbornene-2 -1-methylcyclohexyl carboxylate, 2-methyl-2-adamantyl 5-norbornene-2-carboxylate, 2-ethyl-2-adamantyl 5-norbornene-2-carboxylate, 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 -Oxocyclohexyl) ethyl, 5-norbornene-2-carboxylic acid 1- (1-adap Pentyl) -1-methylethyl and the like.

  The content of the structural unit derived from the monomer represented by the formula (a1-3) in the polymer is usually 10 to 95 mol%, preferably 15 to 90 mol%, in all units of the polymer. More preferably, it is 20-85 mol%.

［式（ａ１−４）中、
Ｒ¹⁰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。
Ｒ¹¹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、アクリロイル基又はメタクリロイル基を表す。
ｌａは０〜４の整数を表す。ｌａが２以上の整数である場合、複数のＲ¹¹は同一であっても異なってもよい。
Ｒ¹²及びＲ¹³はそれぞれ独立に、水素原子又は炭素数１〜１２の炭化水素基を表す。
Ｘ^ａ２は、単結合又は置換基を有していてもよい２価の炭素数１〜１７の飽和炭化水素基を表し、前記飽和炭化水素基に含まれる−ＣＨ_２−は−ＣＯ−、−Ｏ−、−Ｓ−、−ＳＯ_２−又は−Ｎ（Ｒ^ｃ）−で置き換わっていてもよい。Ｒ^ｃは、水素原子又は炭素数１〜６のアルキル基を表す。
Ｙ^ａ３は、炭素数１〜１２の脂肪族炭化水素基、炭素数３〜１８の飽和環状炭化水素基又は炭素数６〜１８の芳香族炭化水素基であり、前記脂肪族炭化水素基、飽和環状炭化水素基及び芳香族炭化水素基は、置換基を有していてもよい。］ Examples of the monomer having the acid labile group (1) and the carbon-carbon double bond include a monomer (a1-4) represented by the formula (a1-4).

[In the formula (a1-4),
R ¹⁰ represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom.
R ¹¹ 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 acryloyl group, or methacryloyl. Represents a group.
la represents an integer of 0 to 4. When la is an integer of 2 or more, the plurality of R ¹¹ may be the same or different.
R ¹² and R ¹³ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms.
X ^a2 represents a single bond or a divalent saturated hydrocarbon group having 1 to 17 carbon atoms which may have a substituent, and —CH ₂ — contained in the saturated hydrocarbon group is —CO—, — O—, —S—, —SO ₂ — or —N (R ^c ) — may be substituted. R ^c represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
Y ^a3 is an aliphatic hydrocarbon group having 1 to 12 carbon atoms, a saturated cyclic hydrocarbon group having 3 to 18 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms, and the aliphatic hydrocarbon group, saturated The cyclic hydrocarbon group and the aromatic hydrocarbon group may have a substituent. ]

Examples of the alkyl group that may have a halogen atom include a perfluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group, a perfluorotert-butyl group, and a perfluoropentyl group. Perfluorohexyl group, perchloromethyl group, perbromomethyl group, periodomethyl group and the like.
Examples of the alkoxy group include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, a sec-butoxy group, a tert-butoxy group, an n-pentoxy group, and an n-hexoxy group. .
Examples of the acyl group include acetyl, propionyl, butyryl and the like.
Examples of the acyloxy group include acetyloxy, propionyloxy, butyryloxy and the like.
Examples of the hydrocarbon group include an aliphatic hydrocarbon group, a saturated cyclic hydrocarbon group, and an aromatic hydrocarbon group.
As aromatic hydrocarbon group, phenyl group, naphthyl group, anthranyl group, p-methylphenyl group, p-tert-butylphenyl group, p-adamantylphenyl group, tolyl group, xylyl group, cumenyl group, mesityl group, biphenyl Groups, anthryl groups, phenanthryl groups, 2,6-diethylphenyl groups, aryl groups such as 2-methyl-6-ethylphenyl, and the like.

The alkyl group for R ¹⁰ and R ¹¹ preferably has 1 to 4 carbon atoms, more preferably 1 or 2 carbon atoms, and particularly preferably a methyl group.
As the alkoxy group for R ¹¹ , C 1 or 2 is more preferable, and a methoxy group is particularly preferable.
Examples of the hydrocarbon group for R ¹² and R ¹³ include isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, octyl group, 2-ethylhexyl group, cyclohexyl group, adamantyl group, A 2-alkyl-2-adamantyl group, a 1- (1-adamantyl) -1-alkyl group, an isobornyl group, and the like are preferable.
Examples of the substituent that X ^a2 and Y ^a3 may have include 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, A C2-C4 acyloxy group etc. are mentioned. Of these, a hydroxy group is preferable.

  As a monomer (a1-4), the following monomers are mentioned, for example.

  The content of the structural unit derived from the monomer represented by the formula (a1-4) in the polymer is usually 10 to 95 mol%, preferably 15 to 90 mol%, in all units of the polymer. More preferably, it is 20-85 mol%.

The polymer is preferably a salt represented by the formula (I), a monomer (a1) having an acid labile group, a monomer having no acid labile group (hereinafter referred to as “acid stable monomer”) In some cases). An acid stable monomer may be used individually by 1 type, and may use 2 or more types together.
When the resin (A) is a copolymer of a monomer (a1) having an acid labile group and an acid stable monomer, the structural units derived from the monomer (a1) having an acid labile group are all Preferably it is 10-80 mol% with respect to 100 mol% of structural units, More preferably, it is 20-60 mol%. Further, the structural unit derived from the monomer having an adamantyl group (particularly the monomer (a1-1) having an acid labile group) is converted to 15 mol per 100 mol% of the monomer (a1) having an acid labile group. It is preferable to set it as mol% or more. When the ratio of the monomer having an adamantyl group increases, the dry etching resistance of the resist is improved.

  As the acid stable monomer, those having a hydroxy group or a lactone ring are preferred. Derived from an acid stable monomer having a hydroxy group (hereinafter referred to as “acid stable monomer having a hydroxy group (a2)”) or an acid stable monomer having a lactone ring (hereinafter referred to as “acid stable monomer having a lactone ring (a3)”) If the polymer which has a structural unit to use is used, the resolution of a resist and the adhesiveness to a board | substrate can be improved.

<Acid-stable monomer having a hydroxy group (a2)>
When the resist composition is used for KrF excimer laser exposure (248 nm), high energy beam exposure such as electron beam or EUV light, the acid-stable monomer (a2) having a hydroxy group has an acid having a phenolic hydroxyl group which is a hydroxystyrene. It is preferable to use a stable monomer (a2-0). When using short wavelength ArF excimer laser exposure (193 nm) or the like, an acid stable monomer having a hydroxyadamantyl group represented by formula (a2-1) should be used as the acid stable monomer having a hydroxy group (a2). Is preferred. The acid-stable monomer (a2) having a hydroxy group may be used alone or in combination of two or more.

  Examples of the monomer (a2-0) having a phenolic hydroxyl group include styrene monomers such as p- or m-hydroxystyrene represented by the formula (a2-0).

［式（ａ２−０）中、
Ｒ^８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^９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、アクリロイル基又はメタクリロイル基を表す。
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^９は同一であっても異なってもよい。］

[In the formula (a2-0),
R ⁸ represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom.
R ⁹ 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 acryloyl group, or methacryloyl. Represents a group.
ma represents an integer of 0 to 4. When ma is an integer of 2 or more, the plurality of R ⁹ may be the same or different. ]

As the alkyl group for R ^8, an alkyl group having 1 to 4 carbon atoms is preferable, an alkyl group having 1 or 2 carbon atoms is more preferable, and a methyl group is particularly preferable.
Moreover, as an alkoxy group, a C1-C4 alkoxy group is preferable, a C1-C2 alkoxy group is more preferable, and a methoxy group is especially preferable.
ma is preferably 0 to 2, more preferably 0 or 1, and particularly preferably 0.

When obtaining a polymer having a structural unit derived from a monomer having such a phenolic hydroxyl group, the corresponding (meth) acrylic acid ester monomer, acetoxystyrene, and styrene are radically polymerized and then deacetylated with an acid. Can be obtained by:
Examples of the monomer having a phenolic hydroxyl group include the following monomers.

  Of the above monomers, 4-hydroxystyrene or 4-hydroxy-α-methylstyrene is particularly preferred.

  The content of the structural unit derived from the monomer represented by the formula (a2-0) in the polymer is usually from 5 to 90 mol%, preferably from 10 to 85 mol%, in all units of the polymer. More preferably, it is 15-80 mol%.

  Examples of the acid stable monomer having a hydroxyadamantyl group include a monomer represented by the formula (a2-1).

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。

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.

  As an acid stable monomer (a2-1) which has a hydroxyadamantyl group, the following are mentioned, for example. Among them, 3-hydroxy-1-adamantyl (meth) acrylate, 3,5-dihydroxy-1-adamantyl (meth) acrylate, and 1- (3,5-dihydroxy-1-adamantyloxycarbonyl) methyl (meth) acrylate are Preferably, 3-hydroxy-1-adamantyl (meth) acrylate and 3,5-dihydroxy-1-adamantyl (meth) acrylate are more preferable, 3-hydroxy-1-adamantyl methacrylate and 3,5-dihydroxy-1-adamantyl methacrylate Is more preferable.

  The content of the structural unit derived from the monomer represented by the formula (a2-1) in the polymer is usually 3 to 40 mol%, preferably 5 to 35 mol% in all units of the polymer. More preferably, it is 5-30 mol%.

<Acid-stable monomer having a lactone ring (a3)>
The lactone ring possessed by the acid stable monomer (a3) may be, for example, a monocycle such as a β-propiolactone ring, γ-butyrolactone ring, or δ-valerolactone ring. The condensed ring may be used. Among these lactone rings, a γ-butyrolactone ring and a condensed ring of a γ-butyrolactone ring and another ring are preferable.

  The acid-stable monomer (a3) having a lactone ring is preferably represented by the formula (a3-1), the formula (a3-2) or the formula (a3-3). These 1 type may be used independently and may use 2 or more types together.

式（ａ３−１）〜式（ａ３−３）中、
Ｌ^a4〜Ｌ^a6は、それぞれ独立に、−Ｏ−又は^＊−Ｏ−（ＣＨ₂）_k3−ＣＯ−Ｏ−を表す。
ｋ３は１〜７の整数を表す。＊は−ＣＯ−との結合手を表す。
Ｒ^a18〜Ｒ^a20は、それぞれ独立に、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。
Ｒ^a22及びＲ^a23は、それぞれ独立に、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及びｒ１は、それぞれ独立に０〜３の整数を表す。ｐ１、ｑ１又はｒ１が２以上のとき、それぞれ、複数のＲ^a21、Ｒ^a22又はＲ^a23は、互いに同一でも異なってもよい。

In formula (a3-1) to formula (a3-3),
L ^{a4 to} L ^a6 each independently represent —O— or ^* —O— (CH ₂ ) _k3 —CO—O—.
k3 represents an integer of 1 to 7. * Represents a bond with -CO-.
R ^{a18 to} R ^a20 each independently 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.
R ^a22 and R ^a23 each independently represent a carboxy group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
q1 and r1 each independently represents an integer of 0 to 3. When p1, q1 or r1 is 2 or more, a plurality of R ^a21 , R ^a22 or R ^a23 may be the same as or different from each other.

In the formula (a3-1) to the formula (a3-3), examples of L ^{a4 to} L ^a6 include those described for L ^a3 .
L ^{a4 to} L ^a6 are each independently preferably —O— or ^* —O— (CH ₂ ) _d1 —CO—O— (the d1 is an integer of 1 to 4), more preferably. Is —O—.
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 to r1 are each independently preferably 0 to 2, more preferably 0 or 1.

  Examples of the acid stable monomer (a3-1) having a γ-butyrolactone ring include the following.

  As the acid stable monomer (a3-1) having a γ-butyrolactone ring, an acid labile monomer can also be exemplified. For example, the following are mentioned.

  Examples of the acid stable monomer (a3-2) having a condensed ring of γ-butyrolactone ring and norbornane ring include the following.

  As the acid stable monomer (a3-2) having a condensed ring of γ-butyrolactone ring and norbornane ring, an acid labile monomer can be exemplified. For example, the following are mentioned.

  Examples of the acid stable monomer (a3-3) having a condensed ring of γ-butyrolactone ring and cyclohexane ring include the following.

  An acid labile monomer can also be exemplified as the monomer (a3-3) having a condensed ring of γ-butyrolactone ring and cyclohexane ring. For example, the following are mentioned.

Among acid-stable monomers (a3) having a lactone ring, (meth) acrylic acid (5-oxo-4-oxatricyclo [4.2.1.0 ^3,7 ] nonan-2-yl, (meth) acrylic Acid tetrahydro-2-oxo-3-furyl, 2- (5-oxo-4-oxatricyclo [4.2.1.0 ^3,7 ] nonan-2-yloxy) -2-oxoethyl (meth) acrylate Are preferred, and those in the form of methacrylate are more preferred.

  Content of the structural unit derived from the monomer represented by the formula (a3-1), the formula (a3-2) or the formula (a3-3) in the polymer is usually 5 to 60 mol in all units of the polymer. %, Preferably 10 to 55 mol%, more preferably 15 to 50 mol%.

<Other acid stable monomers (a4)>
Examples of the other acid stable monomer (a4) include maleic anhydride represented by formula (a4-1), itaconic anhydride represented by formula (a4-2), and formula (a4-3). And acid-stable monomers having a norbornene ring.

式（ａ４−３）中、
Ｒ^a25及びＲ^a26は、それぞれ独立に、水素原子、置換基（例えば、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、シアノ基、カルボキシ基又はアルコキシカルボニル基（−ＣＯＯＲ^a27）を表すか、或いはＲ^a25及びＲ^a26は互いに結合して−ＣＯ−Ｏ−ＣＯ−を形成し、
Ｒ^a27は、炭素数１〜１８の脂肪族炭化水素基又は炭素数３〜１８の飽和環状炭化水素基を表し、脂肪族炭化水素基及び飽和環状炭化水素基の−ＣＨ_２−は、−Ｏ−又は−ＣＯ−で置き換わっていてもよい。但し−ＣＯＯＲ^a27が酸不安定基となるものは除く（即ちＲ^a27は、３級炭素原子が−Ｏ−と結合するものを含まない）。

In formula (a4-3),
R ^a25 and R ^a26 each independently represent a hydrogen atom, an aliphatic hydrocarbon group having 1 to 3 carbon atoms which may have a substituent (for example, a hydroxy group), a cyano group, a carboxy group, or an alkoxycarbonyl group. (—COOR ^a27 ) or R ^a25 and R ^a26 combine with each other to form —CO—O—CO—,
R ^a27 represents an aliphatic hydrocarbon group having 1 to 18 carbon atoms or a saturated cyclic hydrocarbon group having 3 to 18 carbon atoms, and —CH ₂ — of the aliphatic hydrocarbon group and the saturated cyclic hydrocarbon group is —O _2. -Or -CO- may be substituted. However, those in which —COOR ^a27 is an acid labile group are excluded (that is, R ^a27 does not include those in which a tertiary carbon atom is bonded to —O—).

^Examples of the aliphatic hydrocarbon group which may have a substituent for R ^a25 and R ^a26 include a methyl group, an ethyl group, a propyl group, a hydroxymethyl group, and a 2-hydroxyethyl group.
The aliphatic hydrocarbon group for R ^a27 preferably has 1 to 8 carbon atoms, more preferably 1 to 6 carbon atoms. The saturated cyclic hydrocarbon group preferably has 4 to 18 carbon atoms, more preferably 4 to 12 carbon atoms.
^Examples of R ^a27 include a methyl group, an ethyl group, a propyl group, a 2-oxo-oxolan-3-yl group, and a 2-oxo-oxolan-4-yl group.

  Examples of the acid-stable monomer (a4-3) having a norbornene ring include 2-norbornene, 2-hydroxy-5-norbornene, 5-norbornene-2-carboxylic acid, methyl 5-norbornene-2-carboxylate, 5- Examples include norbornene-2-carboxylic acid 2-hydroxy-1-ethyl, 5-norbornene-2-methanol, and 5-norbornene-2,3-dicarboxylic acid anhydride.

  The content of the structural unit derived from the monomer represented by formula (a4-1), formula (a4-2) or formula (a4-3) in the polymer is usually 2 to 40 mol in all units of the polymer. %, Preferably 3 to 30 mol%, more preferably 5 to 20 mol%.

  Preferred polymers are at least a salt represented by the formula (I), a monomer (a1) having an acid labile group, an acid stable monomer (a2) having a hydroxy group, and / or an acid stable monomer having a lactone ring. It is a copolymer obtained by polymerizing (a3). In this preferred copolymer, the monomer (a1) having an acid labile group is more preferably at least one of a monomer (a1-1) having an adamantyl group and a monomer (a1-2) having a cyclohexyl group. A species (more preferably a monomer (a1-1) having an adamantyl group), and an acid stable monomer (a2) having a hydroxy group, preferably an acid stable monomer (a2-1) having a hydroxyadamantyl group, and a lactone The acid-stable monomer (a3) having a ring is more preferably an acid-stable monomer (a3-1) having a γ-butyrolactone ring and an acid-stable monomer (a3-2) having a condensed ring of a γ-butyrolactone ring and a norbornane ring At least one of the following. The polymer (D) can be produced by a known polymerization method (for example, radical polymerization method).

  The weight average molecular weight of the polymer (D) is preferably 2,500 or more (more preferably 3,000 or more) and 50,000 or less (more preferably 30,000 or less).

<First resist composition>
The first resist composition of the present invention contains an acid generator containing a salt represented by the formula (I) and a resin, and may further contain other acid generators.

  The content of the acid generator containing the salt represented by the formula (I) as an active ingredient is preferably 1 part by mass or more (more preferably 3 parts by mass or more) with respect to 100 parts by mass of the resin (A) described later. ), Preferably 30 parts by mass or less (more preferably 25 parts by mass or less).

<Resin (hereinafter sometimes referred to as “resin (A)”>
The resin contained in the first resist composition of the present invention is a resin containing a structural unit derived from a monomer different from the salt represented by the formula (I) in the polymer.

  A preferred resin (A) is a copolymer obtained by polymerizing at least a monomer (a1) having an acid labile group, an acid stable monomer (a2) having a hydroxy group, and / or an acid stable monomer (a3) having a lactone ring. It is a polymer. In this preferred copolymer, the monomer (a1) having an acid labile group is more preferably at least one of a monomer (a1-1) having an adamantyl group and a monomer (a1-2) having a cyclohexyl group. A species (more preferably a monomer (a1-1) having an adamantyl group), and an acid stable monomer (a2) having a hydroxy group, preferably an acid stable monomer (a2-1) having a hydroxyadamantyl group, and a lactone The acid-stable monomer (a3) having a ring is more preferably an acid-stable monomer (a3-1) having a γ-butyrolactone ring and an acid-stable monomer (a3-2) having a condensed ring of a γ-butyrolactone ring and a norbornane ring At least one of the following. Resin (A) can be manufactured by a well-known polymerization method (for example, radical polymerization method).

The weight average molecular weight of the resin (A) is preferably 2,500 or more (more preferably 3,000 or more) and 50,000 or less (more preferably 30,000 or less).
It is preferable that content of resin (A) is 80 mass% or more in solid content of a composition.
In the present specification, the “solid content in the composition” means the total of resist composition components excluding the solvent (E) described later. The solid content in the composition and the content of the resin (A) relative thereto can be measured by a known analysis means such as liquid chromatography or gas chromatography.

<Other acid generators (hereinafter sometimes referred to as “acid generator (B)”)>
The acid generator (B) is classified into a nonionic type and an ionic type. Nonionic acid generators include organic halides, sulfonate esters (for example, 2-nitrobenzyl ester, aromatic sulfonate, oxime sulfonate, N-sulfonyloxyimide, N-sulfonyloxyimide, sulfonyloxyketone, DNQ 4- Sulfonate), sulfones (for example, disulfone, ketosulfone, sulfonyldiazomethane) and the like. The ionic acid generator is typically an onium salt containing an onium cation (for example, diazonium salt, phosphonium salt, sulfonium salt, iodonium salt). Examples of the anion of the onium salt include a sulfonate anion, a sulfonylimide anion, and a sulfonylmethide anion.

  Examples of the acid generator (B) include not only an acid generator (particularly a photoacid generator) used in the resist field, but also a photoinitiator for photocationic polymerization, a photodecolorant for dyes, or a photochromic agent. Known compounds that generate an acid by radiation (light) and mixtures thereof can also be used as appropriate. For example, JP-A 63-26653, JP-A 55-164824, JP-A 62-69263, JP-A 63-146038, JP-A 63-163452, JP-A 62-153853, Acid can be obtained by radiation described in Japanese Utility Model Laid-Open No. 63-146029, U.S. Pat. No. 3,779,778, U.S. Pat. The resulting compound can be used.

  The acid generator (B) is preferably a fluorine-containing acid generator, more preferably a sulfonate represented by the formula (B1) (hereinafter sometimes referred to as “acid generator (B1)”).

［式（Ｂ１）中、
Ｑ¹及びＱ²は、それぞれ独立に、フッ素原子又は炭素数１〜６のペルフルオロアルキル基を表す。
Ｌ^b1は、単結合又は２価の炭素数１〜１７の飽和炭化水素基を表し、前記２価の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。
Ｙは、置換基を有していてもよい炭素数１〜１８の脂肪族炭化水素基又は置換基を有していてもよい炭素数３〜１８の飽和環状炭化水素基を表し、前記脂肪族炭化水素基及び前記飽和環状炭化水素基に含まれる−ＣＨ_２−は、−Ｏ−、−ＳＯ_２−又は−ＣＯ−で置き換わっていてもよい。
Ｚ⁺は、有機カチオンを表す。］

[In the formula (B1),
Q ¹ and Q ² each independently represents a fluorine atom or a C 1-6 perfluoroalkyl group.
L ^b1 represents a single bond or a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, and —CH ₂ — contained in the divalent saturated hydrocarbon group is replaced by —O— or —CO—. May be.
Y represents an aliphatic hydrocarbon group having 1 to 18 carbon atoms which may have a substituent or a saturated cyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent, and the aliphatic group —CH ₂ — contained in the hydrocarbon group and the saturated cyclic hydrocarbon group may be replaced by —O—, —SO ₂ — or —CO—.
Z ⁺ represents an organic cation. ]

Examples of the perfluoroalkyl group include a perfluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluoro sec-butyl group, a perfluoro tert-butyl group, a perfluoropentyl group, and a perfluorohexyl group. It is done.
In formula (B1), Q ¹ and Q ² are each independently preferably a perfluoromethyl group or a fluorine atom, more preferably a fluorine atom.

Examples of the divalent saturated hydrocarbon group include a linear alkylene group, a branched alkylene group, a monocyclic or polycyclic saturated cyclic hydrocarbon group, and a combination of two or more of these groups But you can.
Specifically, methylene group, ethylene group, propane-1,3-diyl group, propane-1,2-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1 , 6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group , Dodecane-1,12-diyl group, tridecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, hexadecane-1,16-diyl group, heptadecane-1, Linear alkylene groups such as 17-diyl group, methylidene group, ethylidene group, propylidene group, 2-propylidene group;
On the side of an alkyl group (particularly an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group) Having a chain, for example, 1-methyl-1,3-propylene group, 2-methyl-1,3-propylene group, 2-methyl-1,2-propylene group, 1-methyl-1,4-butylene Group, branched alkylene such as 2-methyl-1,4-butylene group;
Monocyclic saturated cyclic hydrocarbon groups which are cycloalkylene groups such as 1,3-cyclobutylene group, 1,3-cyclopentylene group, 1,4-cyclohexylene group, 1,5-cyclooctylene group;
Examples thereof include polycyclic saturated cyclic hydrocarbon groups such as 1,4-norbornylene group, 2,5-norbornylene group, 1,5-adamantylene group, 2,6-adamantylene group and the like.

Examples of the group in which —CH ₂ — contained in the saturated hydrocarbon group of L ^b1 is replaced by —O— or —CO— include formula (b1-1) to formula (b1-6). L ^b1 is preferably any one of formulas (b1-1) to (b1-4), more preferably formula (b1-1) or formula (b1-2). Incidentally, the formula (b1-1) ~ formula (b1-6) are described together the left and right in the equation (B1), the left ^{C (Q 1) (Q 2} ) - bound to, the right side Combines with -Y. The same applies to specific examples of the following formulas (b1-1) to (b1-6).

式（ｂ１−１）〜式（ｂ１−６）中、
Ｌ^b2は、単結合又は炭素数１〜１５の飽和炭化水素基を表す。
Ｌ^b3は、単結合又は炭素数１〜１２の飽和炭化水素基を表す。
Ｌ^b4は、炭素数１〜１３の飽和炭化水素基を表す。但しＬ^b3及びＬ^b4の炭素数上限は１３である。
Ｌ^b5は、炭素数１〜１５の飽和炭化水素基を表す。
Ｌ^b6及びＬ^b7は、それぞれ独立に、炭素数１〜１５の飽和炭化水素基を表す。但しＬ^b6及びＬ^b7の炭素数上限は１６である。
Ｌ^b8は、炭素数１〜１４の飽和炭化水素基を表す。
Ｌ^b9及びＬ^b10は、それぞれ独立に、炭素数１〜１１の飽和炭化水素基を表す。但しＬ^ｂ９及びＬ^ｂ１０の炭素数上限は１２である。
中でも、式（ｂ１−１）で表される２価の基が好ましく、Ｌ^b2が単結合又は−ＣＨ_２−である式（ｂ１−１）で表される２価の基がより好ましい。

In formula (b1-1) to formula (b1-6),
L ^b2 represents a single bond or a saturated hydrocarbon group having 1 to 15 carbon atoms.
L ^b3 represents a single bond or a saturated hydrocarbon group having 1 to 12 carbon atoms.
L ^b4 represents a saturated hydrocarbon group having 1 to 13 carbon atoms. However, the upper limit of the carbon number of L ^b3 and L ^b4 is 13.
L ^b5 represents a saturated hydrocarbon group having 1 to 15 carbon atoms.
L ^b6 and L ^b7 each independently represent a saturated hydrocarbon group having 1 to 15 carbon atoms. However, the upper limit of the carbon number of L ^b6 and L ^b7 is 16.
L ^b8 represents a saturated hydrocarbon group having 1 to 14 carbon atoms.
L ^b9 and L ^b10 each independently represent a saturated hydrocarbon group having 1 to 11 carbon atoms. However, the upper limit of the carbon number of L ^b9 and L ^b10 is 12.
Among these, a divalent group represented by the formula (b1-1) is preferable, and a divalent group represented by the formula (b1-1) in which L ^b2 is a single bond or —CH ₂ — is more preferable.

Examples of the divalent group represented by the formula (b1-1) include the following.

Examples of the divalent group represented by the formula (b1-2) include the following.

Examples of the divalent group represented by the formula (b1-3) include the following.

Examples of the divalent group represented by the formula (b1-4) include the following.

Examples of the divalent group represented by the formula (b1-5) include the following.

Examples of the divalent group represented by the formula (b1-6) include the following.

The saturated hydrocarbon group for L ^b1 may have a substituent. Examples of the substituent include a halogen atom, a hydroxy group, a carboxy group, an aromatic hydrocarbon group having 6 to 18 carbon atoms, an aralkyl group having 7 to 21 carbon atoms, an acyl group having 2 to 4 carbon atoms, and a glycidyloxy group. Is mentioned.
Examples of the aralkyl group include benzyl, phenethyl, phenylpropyl, trityl, naphthylmethyl group, naphthylethyl group, and the like.

As the aliphatic hydrocarbon group for Y, an alkyl group having 1 to 6 carbon atoms is preferable.
Examples of the substituent of the aliphatic hydrocarbon group and the saturated cyclic hydrocarbon group include a halogen atom (excluding a fluorine atom), a hydroxy group, an oxo group, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, and a hydroxy group. C1-C12 aliphatic hydrocarbon group, C3-C16 saturated cyclic hydrocarbon group, C1-C12 alkoxy group, C6-C18 aromatic hydrocarbon group, C7-C21 An aralkyl group, an acyl group having 2 to 4 carbon atoms, a glycidyloxy group, or — (CH ₂ ) _j2 —O—CO—R ^b1 group (wherein R ^b1 is an aliphatic hydrocarbon group having 1 to 16 carbon atoms) Represents a saturated cyclic hydrocarbon group having 3 to 16 carbon atoms or an aromatic hydrocarbon group having 6 to 18 carbon atoms, j2 represents an integer of 0 to 4). The aliphatic hydrocarbon group, saturated cyclic hydrocarbon group, aromatic hydrocarbon group, aralkyl group, and the like, which are substituents for Y, may further have a substituent. Examples of the substituent include an alkyl group, a halogen atom, a hydroxy group, and an oxo group.
Examples of the hydroxy group-containing aliphatic hydrocarbon group include a hydroxymethyl group and a hydroxyethyl group.

In particular, examples of the saturated cyclic hydrocarbon group for Y include groups represented by formulas (Y1) to (Y26).

  Especially, it is preferably a group represented by any one of formulas (Y1) to (Y19), more preferably represented by formula (Y11), formula (Y14), formula (Y15) or formula (Y19). And more preferably a group represented by formula (Y11) or formula (Y14).

Examples of Y that is a saturated cyclic hydrocarbon group substituted with an aliphatic hydrocarbon group include the following.

  Examples of Y that is a saturated cyclic hydrocarbon group substituted with a hydroxy group or a hydroxy group-containing aliphatic hydrocarbon group include the following.

  Examples of Y, which is a saturated cyclic hydrocarbon group substituted with an aromatic hydrocarbon group, include the following.

Examples of Y that is a saturated cyclic hydrocarbon group substituted by — (CH ₂ ) _j2 —O—CO—R ^b1 group include the following.

  Y is preferably an adamantyl group which may have a substituent (for example, an oxo group or the like), more preferably an adamantyl group or an oxoadamantyl group.

Examples of the sulfonate anion in the salt represented by the formula (B1) include, for example, the following formulas (b1-1-1) to (b1-1-1-) in which the substituent L ^b1 is the formula (b1-1). The anion represented by 9) is preferred. In the following formulae, the definition of the substituent has the same meaning as described above, and the substituents R ^b2 and R ^b3 each independently represent an aliphatic hydrocarbon group having 1 to 4 carbon atoms (preferably a methyl group). .

Saturated cyclic substituted with a sulfonate anion or an aliphatic hydrocarbon group containing Y which is an aliphatic hydrocarbon group or an unsubstituted saturated cyclic hydrocarbon group and a divalent group represented by the formula (b1-1) Examples of the sulfonate anion containing Y which is a hydrocarbon group and the divalent group represented by the formula (b1-1) include the following.

As the sulfonate anion containing Y which is a saturated cyclic hydrocarbon group substituted with — (CH ₂ ) _j2 —O—CO—R ^b1 group and a divalent group represented by the formula (b1-1), For example, the following are mentioned.

  Examples of the sulfonate anion containing Y which is a saturated cyclic hydrocarbon group substituted with a hydroxy group or a hydroxy group-containing aliphatic hydrocarbon group and a divalent group represented by the formula (b1-1) include the following: Things.

  Examples of the sulfonate anion containing Y which is a saturated cyclic hydrocarbon group substituted with an aromatic hydrocarbon group or an aralkyl group and a divalent group represented by the formula (b1-1) include the following. It is done.

Examples of the sulfonate anion containing Y which is a cyclic ether and the divalent group represented by the formula (b1-1) include the following.

Examples of the sulfonate anion containing Y which is a lactone ring and the divalent group represented by the formula (b1-1) include the following.

  Examples of the sulfonate anion containing Y which is a saturated cyclic hydrocarbon having an oxo group and a divalent group represented by the formula (b1-1) include the following.

Examples of the sulfonate anion containing Y which is a sultone ring and the divalent group represented by the formula (b1-1) include the following.

Saturated cyclic substituted with a sulfonate anion or an aliphatic hydrocarbon group containing Y which is an aliphatic hydrocarbon group or an unsubstituted saturated cyclic hydrocarbon group and a divalent group represented by the formula (b1-2) Examples of the sulfonate anion containing Y which is a hydrocarbon group and the divalent group represented by the formula (b1-2) include the following.

As the sulfonate anion containing Y which is a saturated cyclic hydrocarbon group substituted with — (CH ₂ ) _j2 —O—CO—R ^b1 group and a divalent group represented by the formula (b1-2), For example, the following are mentioned.

  Examples of the sulfonate anion containing Y which is a saturated cyclic hydrocarbon group substituted with a hydroxy group or a hydroxy group-containing aliphatic hydrocarbon group and a divalent group represented by the formula (b1-2) include the following: Things.

  Examples of the sulfonate anion containing Y, which is a saturated cyclic hydrocarbon group substituted with an aromatic hydrocarbon group, and a divalent group represented by the formula (b1-2) include the following.

  Examples of the sulfonate anion containing Y which is a cyclic ether and the divalent group represented by the formula (b1-2) include the following.

  Examples of the sulfonate anion containing Y which is a lactone ring and the divalent group represented by the formula (b1-2) include the following.

  Examples of the sulfonate anion containing Y having an oxo group and the divalent group represented by the formula (b1-2) include the following.

  Examples of the sulfonate anion containing Y which is a sultone ring and the divalent group represented by the formula (b1-2) include the following.

  Y which is an aliphatic hydrocarbon group or a saturated cyclic hydrocarbon group substituted with a sulfonate anion or an aliphatic hydrocarbon group containing an unsubstituted Y and a divalent group represented by the formula (b1-3) Examples of the sulfonate anion containing the divalent group represented by the formula (b1-3) include the following.

  Examples of the sulfonate anion containing Y, which is a saturated cyclic hydrocarbon group substituted with an alkoxy group, and a divalent group represented by the formula (b1-3) include the following.

  Examples of the sulfonate anion containing Y which is a saturated cyclic hydrocarbon group substituted with a hydroxy group or a hydroxy group-containing aliphatic hydrocarbon group and a divalent group represented by the formula (b1-3) include the following: Things.

  Examples of the sulfonate anion containing Y having an oxo group and the divalent group represented by the formula (b1-3) include the following.

  Examples of the sulfonate anion containing Y, which is a saturated cyclic hydrocarbon group substituted with an aliphatic hydrocarbon group, and a divalent group represented by the formula (b1-4) include the following.

  Examples of the sulfonate anion containing Y which is a saturated cyclic hydrocarbon group substituted with an alkoxy group and a divalent group represented by the formula (b1-4) include the following.

  Examples of the sulfonate anion containing Y which is a saturated cyclic hydrocarbon group substituted with a hydroxy group or a hydroxy group-containing aliphatic hydrocarbon group and a divalent group represented by the formula (b1-4) include the following: Things.

  Examples of the sulfonate anion containing Y which is a saturated cyclic hydrocarbon group having an oxo group and a divalent group represented by the formula (b1-4) include the following.

Among these, the following sulfonate anions having a divalent group represented by the formula (b1-1) are more preferable.

^{Examples of the} cation contained in the acid generator (B) include the same cation as Z ¹⁺ .

  The acid generator (B1) is a combination of the above-described sulfonate anion and organic cation. The above-mentioned anion and cation can be arbitrarily combined, but any one of anion (b1-1-1) to anion (b1-1-9) and a cation (b2-1-1), and an anion ( A combination of any one of b1-1-3) to (b1-1-5) and a cation (b2-3) is preferable.

  Preferred acid generators (B1) are those represented by formula (B1-1) to formula (B1-17). Among them, acid generators (B1-1), (B1-2), (B1-6), (B1-11), (B1-12), (B1-13) and (B1-14) containing a triphenylsulfonium cation ) Is more preferable.

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

<Second resist composition>
The second resist composition of the present invention contains the polymer (D) and may further contain an acid generator.
The content of the polymer is preferably 80% by mass or more in the solid content of the composition.
In the present specification, the “solid content in the composition” means the total of resist composition components excluding the solvent (E) described later. The solid content in the composition and the content of the resin (A) relative thereto can be measured by a known analysis means such as liquid chromatography or gas chromatography.

Examples of the acid generator contained in the second resist composition include a salt represented by the formula (I) and an acid generator (B).
The content of the acid generator is preferably 1 part by mass or more (more preferably 3 parts by mass or more), preferably 30 parts by mass or less (more preferably 25 parts by mass or less) with respect to 100 parts by mass of the polymer (D). ).

<Basic compound (hereinafter sometimes referred to as “basic compound (C)”)>
The resist composition of the present invention suitably contains a basic compound (C).
The content of the basic compound (C) is preferably about 0.01 to 1% by mass based on the solid content of the resist composition.

  The basic compound (C) is preferably a basic nitrogen-containing organic compound (for example, an amine). The amine may be an aliphatic amine or an aromatic amine. As the aliphatic amine, any of primary amine, secondary amine and tertiary amine can be used. The aromatic amine may be any of an amino group bonded to an aromatic ring such as aniline and a heteroaromatic amine such as pyridine. Preferable basic compound (C) includes an aromatic amine represented by the formula (C2), particularly an aniline represented by the formula (C2-1).

ここで、Ａｒ^c1は、芳香族炭化水素基を表す。
Ｒ^c5及びＲ^c6は、それぞれ独立に、水素原子、脂肪族炭化水素基（好ましくはアルキル基又はシクロアルキル基）、飽和環状炭化水素基又は芳香族炭化水素基を表す。但し前記脂肪族炭化水素基、前記飽和環状炭化水素基又は前記芳香族炭化水素基の水素原子は、ヒドロキシ基、アミノ基、又は炭素数１〜６のアルコキシ基で置換されていてもよく、前記アミノ基は、炭素数１〜４のアルキル基で置換されていてもよい。
前記脂肪族炭化水素基は、好ましくは炭素数１〜６程度であり、前記飽和環状炭化水素基は、好ましくは炭素数５〜１０程度であり、前記芳香族炭化水素基は、好ましくは炭素数６〜１０程度である。
Ｒ^c7は、脂肪族炭化水素基（好ましくはアルキル基）、アルコキシ基、飽和環状炭化水素基（好ましくはシクロアルキル基）又は芳香族炭化水素基を表す。但し脂肪族炭化水素基、アルコキシ基、飽和環状炭化水素基及び芳香族炭化水素基の水素原子は、上記と同様の置換基を有していてもよい。
ｍ３は０〜３の整数を表す。ｍ３が２以上のとき、複数のＲ^c7は、互いに同一でも異なってもよい。
Ｒ^c7の脂肪族炭化水素基、飽和環状炭化水素基及び芳香族炭化水素基の好ましい炭素数は、上記と同じであり、Ｒ^c7のアルコキシ基は、好ましくは炭素数１〜６程度である。

Here, Ar ^c1 represents an aromatic hydrocarbon group.
R ^c5 and R ^c6 each independently represents a hydrogen atom, an aliphatic hydrocarbon group (preferably an alkyl group or a cycloalkyl group), a saturated cyclic hydrocarbon group or an aromatic hydrocarbon group. However, the hydrogen atom of the aliphatic hydrocarbon group, the saturated cyclic hydrocarbon group or the aromatic hydrocarbon group may be substituted with a hydroxy group, an amino group, or an alkoxy group having 1 to 6 carbon atoms, The amino group may be substituted with an alkyl group having 1 to 4 carbon atoms.
The aliphatic hydrocarbon group preferably has about 1 to 6 carbon atoms, the saturated cyclic hydrocarbon group preferably has about 5 to 10 carbon atoms, and the aromatic hydrocarbon group preferably has about carbon atoms. It is about 6-10.
R ^c7 represents an aliphatic hydrocarbon group (preferably an alkyl group), an alkoxy group, a saturated cyclic hydrocarbon group (preferably a cycloalkyl group) or an aromatic hydrocarbon group. However, the hydrogen atom of an aliphatic hydrocarbon group, an alkoxy group, a saturated cyclic hydrocarbon group, and an aromatic hydrocarbon group may have a substituent similar to the above.
m3 represents an integer of 0 to 3. When m3 is 2 or more, the plurality of R ^c7 may be the same as or different from each other.
Aliphatic hydrocarbon group R ^c7, preferable number of carbon atoms of the saturated cyclic hydrocarbon group and the aromatic hydrocarbon group are the same as above, an alkoxy group of R ^c7 is independently in, preferably about 1 to 6 carbon atoms.

Examples of the aromatic amine (C2) include 1-naphthylamine and 2-naphthylamine.
Examples of aniline (C2-1) include aniline, diisopropylaniline, 2-, 3- or 4-methylaniline, 4-nitroaniline, N-methylaniline, N, N-dimethylaniline, diphenylamine and the like.
Of these, diisopropylaniline (particularly 2,6-diisopropylaniline) is preferable.

ここで、
Ｒ^c8は、上記Ｒ^c7で説明したいずれかの基を表す。
窒素原子と結合するＲ^c9、Ｒ^c10、Ｒ^c11〜Ｒ^c14、Ｒ^c16〜Ｒ^c19及びＲ^c22は、それぞれ独立に、Ｒ^c5及びＲ^c6で説明したいずれかの基を表す。
芳香族炭素と結合するＲ^c20、Ｒ^c21、Ｒ^c23〜Ｒ^c28は、それぞれ独立に、Ｒ^c7で説明したいずれかの基を表す。
ｏ３〜ｕ３は、それぞれ独立に０〜３の整数を表す。ｏ３〜ｕ３のいずれかが２以上であるとき、それぞれ、複数のＲ^c20〜Ｒ^c28のいずれかは互いに同一でも異なってもよい。
Ｒ^c15は、脂肪族炭化水素基、飽和環状炭化水素基又はアルカノイル基を表す。
ｎ３は０〜８の整数を表す。ｎ３が２以上のとき、複数のＲ^c15は、互いに同一でも異なってもよい。
Ｒ^c15の脂肪族炭化水素基は、好ましくは炭素数１〜６程度であり、飽和環状炭化水素基は、好ましくは炭素数３〜６程度であり、アルカノイル基は、好ましくは炭素数２〜６程度である。
Ｌ^c1及びＬ^c2は、それぞれ独立に、２価の脂肪族炭化水素基（好ましくはアルキレン基）、−ＣＯ−、−Ｃ（＝ＮＨ）−、−Ｃ（＝ＮＲ^c3）−、−Ｓ−、−Ｓ−Ｓ−又はこれらの組合せを表す。前記２価の脂肪族炭化水素基は、好ましくは炭素数１〜６程度である。
Ｒ^c3は、炭素数１〜４のアルキル基を表す。 Examples of the basic compound (C) include compounds represented by the formulas (C3) to (C11).

here,
R ^c8 represents any of the groups described for R ^c7 above.
R ^c9 , R ^c10 , R ^{c11 to} R ^c14 , R ^{c16 to} R ^c19 and R ^c22 bonded to the nitrogen atom each independently represent any of the groups described for R ^c5 and R ^c6 .
R ^c20 , R ^c21 and R ^{c23 to} R ^c28 bonded to the aromatic carbon each independently represents any of the groups described for R ^c7 .
o3 to u3 each independently represents an integer of 0 to 3. When any of o3 to u3 is 2 or more, any of the plurality of R ^{c20 to} R ^c28 may be the same as or different from each other.
R ^c15 represents an aliphatic hydrocarbon group, a saturated cyclic hydrocarbon group or an alkanoyl group.
n3 represents an integer of 0 to 8. When n3 is 2 or more, the plurality of R ^c15 may be the same as or different from each other.
The aliphatic hydrocarbon group represented by R ^c15 preferably has about 1 to 6 carbon atoms, the saturated cyclic hydrocarbon group preferably has about 3 to 6 carbon atoms, and the alkanoyl group preferably has 2 to 6 carbon atoms. Degree.
L ^c1 and L ^c2 are each independently a divalent aliphatic hydrocarbon group (preferably an alkylene group), —CO—, —C (═NH) —, —C (═NR ^c3 ) —, —S—. , -SS- or a combination thereof. The divalent aliphatic hydrocarbon group preferably has about 1 to 6 carbon atoms.
R ^c3 represents an alkyl group having 1 to 4 carbon atoms.

  Examples of the compound (C3) include hexylamine, heptylamine, octylamine, nonylamine, decylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, triethylamine, trimethylamine, tripropylamine, Tributylamine, tripentylamine, trihexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, methyldibutylamine, methyldipentylamine, methyldihexylamine, methyldicyclohexylamine, methyldiheptylamine, methyldioctyl Amine, methyl dinonyl amine, methyl didecyl amine, ethyl dibutyl amine, ethyl dipentyl amine, ethyl di Silamine, ethyldiheptylamine, ethyldioctylamine, ethyldinonylamine, ethyldidecylamine, dicyclohexylmethylamine, tris [2- (2-methoxyethoxy) ethyl] amine, triisopropanolamine ethylenediamine, tetramethylenediamine, hexamethylene Examples include diamine, 4,4′-diamino-1,2-diphenylethane, 4,4′-diamino-3,3′-dimethyldiphenylmethane, 4,4′-diamino-3,3′-diethyldiphenylmethane, and the like.

Examples of the compound (C4) include piperazine.
Examples of the compound (C5) include morpholine.
Examples of the compound (C6) include piperidine and hindered amine compounds having a piperidine skeleton described in JP-A No. 11-52575.
Examples of the compound (C7) include 2,2′-methylenebisaniline.
Examples of the compound (C8) include imidazole and 4-methylimidazole.
Examples of the compound (C9) include pyridine and 4-methylpyridine.
Examples of the compound (C10) include 1,2-di (2-pyridyl) ethane, 1,2-di (4-pyridyl) ethane, 1,2-di (2-pyridyl) ethene, and 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'-dipicolylamine and the like can be mentioned.
Examples of the compound (C11) include bipyridine.

<Solvent (sometimes referred to as "solvent (E)")
The resist composition of the present invention may contain the solvent (E) in an amount of 90% by mass or more in the composition. The resist composition of the present invention containing the solvent (E) is suitable for producing a thin film resist. The content of the solvent (E) is 90% by mass or more (preferably 92% by mass or more, more preferably 94% by mass or more) and 99.9% by mass or less (preferably 99% by mass or less) in the composition.
The content of the solvent (E) can be measured by a known analysis means such as liquid chromatography or 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 And esters such as ethyl pyruvate; ketones such as acetone, methyl isobutyl ketone, 2-heptanone and cyclohexanone; cyclic esters such as γ-butyrolactone; A solvent (E) may be used individually by 1 type, and may use 2 or more types together.

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

<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 mentioned above 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 using an exposure machine;
(4) A step of heating the composition layer after exposure,
(5) The process which develops the composition layer after a heating using a image development apparatus is included.

  Application of the resist composition onto the substrate can be performed by a commonly used apparatus such as a spin coater.

The composition after application is dried to remove the solvent. The removal of the solvent is performed, for example, by evaporating the solvent using a heating device such as a hot plate or by using a decompression device to form a composition layer from which the solvent has been removed. As for the temperature in this case, about 50-200 degreeC is illustrated, for example. The pressure is exemplified by about 1 to 1.0 × 10 ⁵ Pa.

The obtained composition layer is exposed using an exposure machine. The exposure machine may be an immersion exposure machine. At this time, exposure is usually performed through a mask corresponding to a required pattern. The exposure light source emits ultraviolet laser light such as KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), F ₂ laser (wavelength 157 nm), solid-state laser light source (YAG or semiconductor laser, etc.) Various types of laser beam can be used, such as those that convert the wavelength of the laser beam from) to radiate a harmonic laser beam in the far ultraviolet region or the vacuum ultraviolet region.

The composition layer after the exposure is subjected to heat treatment for promoting the deprotection group reaction. As heating temperature, it is about 50-200 degreeC normally, Preferably it is about 70-150 degreeC.
The heated composition layer is usually developed using an alkali developer using a developing device.
The alkaline developer used here may be various alkaline aqueous solutions used in this field. Examples thereof include an aqueous solution of tetramethylammonium hydroxide and (2-hydroxyethyl) trimethylammonium hydroxide (commonly called choline).
After development, it is preferable to rinse with ultrapure water to remove water remaining on the substrate and the pattern.

<Application>
The resist composition of the present invention is suitable as a resist composition for KrF excimer laser exposure, a resist composition for ArF excimer laser exposure, a resist composition for EB, or a resist composition for EUV exposure machines.

Hereinafter, the present invention will be described in detail by way of examples.
In Examples and Comparative Examples, “%” and “part” representing content and use amount are based on mass unless otherwise specified.
The weight average molecular weight is a value obtained by gel permeation chromatography (HLC-8120GPC, manufactured by Tosoh Corporation, three columns are “TSKgel Multipore HXL-M”, and the solvent is tetrahydrofuran) using polystyrene as a standard product.
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)

式（ＩＩ−１）で表される塩を、特開２００８−１２７３６７号公報に記載された方法で合成した。式（ＩＩ−１）で表される塩２０．００部、アセトニトリル８０．００部、式（ＩＩＩ−１）で表される化合物（商品名：カルボニルジイミダゾール 東京化成製）８．８８部を仕込み、８０℃で３０分間攪拌した後、得られた反応物を２３℃まで冷却し、ろ過して、式（ＩＶ−１）で表される塩を含有する溶液１０３．３１部を得た。

式（ＩＶ−１）で表される塩を含有する溶液１０３．３１部及び式（Ｖ−１）で表される化合物（商品名：４−メタクリロイルオキシ−１−ナフトール 川崎化成工業製）９．８９部を仕込み、２３℃で１時間攪拌した後、更に、トリフルオロ酢酸９．３６部を加えて、２３℃で３時間攪拌した後、ろ過した。回収された濾液を濃縮し、得られた濃縮物に、クロロホルム３００部及びイオン交換水７０部を仕込み、３０分間攪拌した後、分液した。この水洗操作を３回繰り返した。回収された有機層を濃縮した後、酢酸エチル６０部を加えて攪拌し、上澄液を除去した。得られた残渣にｔｅｒｔ−ブチルメチルエーテル１００部を加えて攪拌した後、上澄液を除去した。得られた残渣をクロロホルムに溶解し、濃縮してすることにより、式（Ｉ−１）で表される塩６．０３部を得た。 Example 1: [Synthesis of a salt represented by the formula (I-1)]

A salt represented by the formula (II-1) was synthesized by the method described in JP-A-2008-127367. 20.00 parts of a salt represented by the formula (II-1), 80.00 parts of acetonitrile, and 8.88 parts of a compound represented by the formula (III-1) (trade name: carbonyldiimidazole manufactured by Tokyo Chemical Industry Co., Ltd.) After stirring at 80 ° C. for 30 minutes, the obtained reaction product was cooled to 23 ° C. and filtered to obtain 103.31 parts of a solution containing a salt represented by the formula (IV-1).

8. 103.31 parts of a solution containing a salt represented by the formula (IV-1) and a compound represented by the formula (V-1) (trade name: 4-methacryloyloxy-1-naphthol manufactured by Kawasaki Chemical Industries) After 89 parts were charged and stirred at 23 ° C. for 1 hour, 9.36 parts of trifluoroacetic acid was further added and stirred at 23 ° C. for 3 hours, followed by filtration. The collected filtrate was concentrated, and 300 parts of chloroform and 70 parts of ion-exchanged water were added to the resulting concentrate, and the mixture was stirred for 30 minutes and then separated. This washing operation was repeated three times. After the collected organic layer was concentrated, 60 parts of ethyl acetate was added and stirred, and the supernatant was removed. After adding 100 parts of tert-butyl methyl ether to the resulting residue and stirring, the supernatant was removed. The obtained residue was dissolved in chloroform and concentrated to obtain 6.03 parts of the salt represented by the formula (I-1).

MS (ESI (+) Spectrum): M ⁺ 263.1
MS (ESI (-) Spectrum): M ^- 385.0

式（ＩＩ−２）で表される塩を、特開２００８−１２７３６７号公報に記載された方法で合成した。式（ＩＩ−２）で表される塩２０．００部、アセトニトリル８０．００部、式（ＩＩＩ−２）で表される化合物（商品名：カルボニルジイミダゾール 東京化成製）８．８８部を仕込み、８０℃で３０分間攪拌した後、得られた反応物を２３℃まで冷却し、ろ過して、式（ＩＶ−２）で表される塩を含有する溶液１０３．８９部を得た。

式（ＩＶ−２）で表される塩を含有する溶液１０３．８９部及び式（Ｖ−２）で表される化合物（商品名：６−ヒドロキシ−２−ビニルナフタレン 東ソー有機化学製）７．３８部を仕込み、２３℃で３時間攪拌した後、ろ過した。回収された濾液を濃縮し、得られた濃縮物に、クロロホルム３００部及びイオン交換水７０部を仕込み、３０分間攪拌した後、分液した。この水洗操作を３回繰り返した。回収された有機層を濃縮した後、酢酸エチル６０部を加えて攪拌し、上澄液を除去した。得られた残渣にｔｅｒｔ−ブチルメチルエーテル１００部を加えて攪拌した後、上澄液を除去した。得られた残渣をクロロホルムに溶解し、濃縮してすることにより、式（Ｉ−２）で表される塩４．２５部を得た。 Example 2: [Synthesis of salt represented by formula (I-2)]

The salt represented by the formula (II-2) was synthesized by the method described in JP 2008-127367 A. 20.00 parts of a salt represented by the formula (II-2), 80.00 parts of acetonitrile, and 8.88 parts of a compound represented by the formula (III-2) (trade name: carbonyldiimidazole manufactured by Tokyo Chemical Industry Co., Ltd.) After stirring at 80 ° C. for 30 minutes, the obtained reaction product was cooled to 23 ° C. and filtered to obtain 103.89 parts of a solution containing a salt represented by the formula (IV-2).

6. 103.89 parts of a solution containing a salt represented by the formula (IV-2) and a compound represented by the formula (V-2) (trade name: 6-hydroxy-2-vinylnaphthalene, manufactured by Tosoh Organic Chemical Co., Ltd.) 38 parts were charged and stirred at 23 ° C. for 3 hours, followed by filtration. The collected filtrate was concentrated, and 300 parts of chloroform and 70 parts of ion-exchanged water were added to the resulting concentrate, and the mixture was stirred for 30 minutes and then separated. This washing operation was repeated three times. After the collected organic layer was concentrated, 60 parts of ethyl acetate was added and stirred, and the supernatant was removed. After adding 100 parts of tert-butyl methyl ether to the resulting residue and stirring, the supernatant was removed. The obtained residue was dissolved in chloroform and concentrated to obtain 4.25 parts of the salt represented by the formula (I-2).

MS (ESI (+) Spectrum): M ⁺ 263.1
MS (ESI (-) Spectrum): M ^- 327.0

式（ＩＩ−３）で表される塩２０．００部、アセトニトリル８０．００部、式（ＩＩＩ−３）で表される化合物（商品名：カルボニルジイミダゾール 東京化成製）７．７７部を仕込み、８０℃で３０分間攪拌した後、得られた反応物を２３℃まで冷却し、ろ過して、式（ＩＶ−１）で表される塩を含有する溶液１０２．６８部を得た。

式（ＩＶ−３）で表される塩を含有する溶液１０２．６８部及び式（Ｖ−３）で表される化合物１０．４１部を仕込み、２３℃で１時間攪拌した後、更に、トリフルオロ酢酸９．３６部を加えて、２３℃で３時間攪拌した後、ろ過した。回収された濾液を濃縮し、得られた濃縮物に、クロロホルム３００部及びイオン交換水７０部を仕込み、３０分間攪拌した後、分液した。この水洗操作を３回繰り返した。回収された有機層を濃縮した後、酢酸エチル６０部を加えて攪拌し、上澄液を除去した。得られた残渣にｔｅｒｔ−ブチルメチルエーテル１００部を加えて攪拌した後、上澄液を除去した。得られた残渣をクロロホルムに溶解し、濃縮してすることにより、式（Ｉ−３）で表される塩２５．４９部を得た。 Example 3: [Synthesis of salt represented by formula (I-3)]

20.00 parts of salt represented by the formula (II-3), 80.00 parts of acetonitrile, and 7.77 parts of a compound represented by the formula (III-3) (trade name: carbonyldiimidazole manufactured by Tokyo Chemical Industry Co., Ltd.) After stirring at 80 ° C. for 30 minutes, the obtained reaction product was cooled to 23 ° C. and filtered to obtain 102.68 parts of a solution containing a salt represented by the formula (IV-1).

After charging 102.68 parts of a solution containing a salt represented by the formula (IV-3) and 10.41 parts of a compound represented by the formula (V-3) and stirring at 23 ° C. for 1 hour, 9.36 parts of fluoroacetic acid was added and stirred at 23 ° C. for 3 hours, followed by filtration. The collected filtrate was concentrated, and 300 parts of chloroform and 70 parts of ion-exchanged water were added to the resulting concentrate, and the mixture was stirred for 30 minutes and then separated. This washing operation was repeated three times. After the collected organic layer was concentrated, 60 parts of ethyl acetate was added and stirred, and the supernatant was removed. After adding 100 parts of tert-butyl methyl ether to the resulting residue and stirring, the supernatant was removed. The obtained residue was dissolved in chloroform and concentrated to obtain 25.49 parts of the salt represented by the formula (I-3).

MS (ESI (+) Spectrum): M ⁺ 263.1
MS (ESI (-) Spectrum): M ^- 385.0

式（ＩＩ−４）で表される塩２１．９２部、アセトニトリル８７．６８部、式（ＩＩＩ−１）で表される化合物（商品名：カルボニルジイミダゾール 東京化成製）７．７７部を仕込み、８０℃で３０分間攪拌した後、得られた反応物を２３℃まで冷却し、ろ過して、式（ＩＶ−１）で表される塩を含有する溶液１１５．３６部を得た。

式（ＩＶ−４）で表される塩を含有する溶液１１５．３６部及び式（Ｖ−４）で表される化合物１０．４１部を仕込み、２３℃で１時間攪拌した後、更に、トリフルオロ酢酸９．３６部を加えて、２３℃で３時間攪拌した後、ろ過した。回収された濾液を濃縮し、得られた濃縮物に、クロロホルム３００部及びイオン交換水７０部を仕込み、３０分間攪拌した後、分液した。この水洗操作を３回繰り返した。回収された有機層を濃縮した後、酢酸エチル６０部を加えて攪拌し、上澄液を除去した。得られた残渣にｔｅｒｔ−ブチルメチルエーテル１００部を加えて攪拌した後、上澄液を除去した。得られた残渣をクロロホルムに溶解し、濃縮してすることにより、式（Ｉ−４）で表される塩２６．１５部を得た。 Example 4: [Synthesis of salt represented by formula (I-4)]

First, 21.92 parts of a salt represented by the formula (II-4), 87.68 parts of acetonitrile, and 7.77 parts of a compound represented by the formula (III-1) (trade name: carbonyldiimidazole manufactured by Tokyo Chemical Industry Co., Ltd.) are charged. After stirring at 80 ° C. for 30 minutes, the obtained reaction product was cooled to 23 ° C. and filtered to obtain 115.36 parts of a solution containing a salt represented by the formula (IV-1).

A solution containing 115.36 parts of a salt represented by the formula (IV-4) and 10.41 parts of a compound represented by the formula (V-4) were charged and stirred at 23 ° C. for 1 hour. 9.36 parts of fluoroacetic acid was added and stirred at 23 ° C. for 3 hours, followed by filtration. The collected filtrate was concentrated, and 300 parts of chloroform and 70 parts of ion-exchanged water were added to the resulting concentrate, and the mixture was stirred for 30 minutes and then separated. This washing operation was repeated three times. After the collected organic layer was concentrated, 60 parts of ethyl acetate was added and stirred, and the supernatant was removed. After adding 100 parts of tert-butyl methyl ether to the resulting residue and stirring, the supernatant was removed. The obtained residue was dissolved in chloroform and concentrated to obtain 26.15 parts of the salt represented by the formula (I-4).

MS (ESI (+) Spectrum): M ⁺ 305.1
MS (ESI (-) Spectrum): M ^- 385.0

式（Ａ）で表される化合物１５．００部、式（Ｂ）で表される化合物９．９７部、式（Ｃ）で表される化合物３．３５部及び式（Ｉ−１）で表される塩４．６０部を、（モル比５５：３０：１０：５の割合）仕込み、次いで、全モノマーの合計質量に対して、２質量倍のアセトニトリル６５．８５部を加えた。得られた混合物に、開始剤としてアゾビスイソブチロニトリル２．８０部を（全モノマーの合計モル数に対して１２ｍｏｌ％の割合）添加し、これを６時間加熱還流した。その後、反応液を、大量のメタノールと水との混合溶媒（３：１）に注いで沈殿させる操作を３回行うことにより精製、ろ過し、共重合体を得た。
得られた共重合体と、全モノマーの合計質量に対して３質量倍のメチルイソブチルケトン９８．７８部と、全モノマーの合計質量に対して３質量％の割合でｐ−トルエンスルホン酸０．９９部と、全モノマーの合計質量に対して３質量倍のイオン交換水９８．７８部を添加し、２３℃で６時間攪拌した。その後、分液を行い、得られた有機層に、イオン交換水９８．７８部を添加し、水洗を行った。この水洗を４回行った。得られた有機層を濃縮し、残渣にｎ−ヘプタン４２８．０４部を添加した。得られた混合物を、２３℃で３０分間攪拌した後、ろ過し、重量平均分子量が約３．７×１０^３の共重合体２３．８２部を得た。この共重合体は、次式の構造単位を有するものであり、これを重合体Ｄ１とする。 Example 5: [Synthesis of polymer D1]

15.00 parts of the compound represented by the formula (A), 9.97 parts of the compound represented by the formula (B), 3.35 parts of the compound represented by the formula (C) and the formula (I-1) 4.60 parts of the resulting salt was charged (in a molar ratio of 55: 30: 10: 5), and then 65.85 parts of acetonitrile twice the total mass of all monomers were added. To the obtained mixture, 2.80 parts of azobisisobutyronitrile (a ratio of 12 mol% based on the total number of moles of all monomers) was added as an initiator, and this was heated to reflux for 6 hours. Thereafter, the reaction solution was purified and filtered by performing an operation of pouring it into a large amount of a mixed solvent of methanol and water (3: 1) for precipitation three times to obtain a copolymer.
The obtained copolymer, 98.78 parts of methyl isobutyl ketone 3 times by mass with respect to the total mass of all monomers, and p-toluenesulfonic acid at a ratio of 3% by mass with respect to the total mass of all monomers, 99 parts and 98.78 parts of ion-exchanged water 3 times as much as the total mass of all monomers were added and stirred at 23 ° C. for 6 hours. Thereafter, liquid separation was performed, and 98.78 parts of ion-exchanged water was added to the obtained organic layer, followed by washing with water. This washing with water was performed 4 times. The obtained organic layer was concentrated, and 428.04 parts of n-heptane was added to the residue. The resulting mixture was stirred at 23 ° C. for 30 minutes and then filtered to obtain 23.82 parts of a copolymer having a weight average molecular weight of about 3.7 × 10 ³ . This copolymer has a structural unit of the following formula, and this is designated as polymer D1.

式（Ａ）で表される化合物１５．００部、式（Ｂ）で表される化合物９．９７部、式（Ｃ）で表される化合物３．３５部及び式（Ｉ−２）で表される塩４．１９部を、（モル比５５：３０：１０：５の割合）仕込み、次いで、全モノマーの合計質量に対して、２質量倍のアセトニトリル６５．０３部を加えた。得られた混合物に、開始剤としてアゾビスイソブチロニトリル２．８０部を（全モノマーの合計モル数に対して１２ｍｏｌ％の割合）添加し、これを６時間加熱還流した。その後、反応液を、大量のメタノールと水との混合溶媒（３：１）に注いで沈殿させる操作を３回行うことにより精製、ろ過し、共重合体を得た。
得られた共重合体と、全モノマーの合計質量に対して３質量倍のメチルイソブチルケトン９７．５４部と、全モノマーの合計質量に対して３質量％の割合でｐ−トルエンスルホン酸０．９８部と、全モノマーの合計質量に対して３質量倍のイオン交換水９７．５４部を添加し、２３℃で６時間攪拌した。その後、分液を行い、得られた有機層に、イオン交換水９７．５４部を添加し、水洗を行った。この水洗を４回行った。得られた有機層を濃縮し、残渣にｎ−ヘプタン４２２．６９部を添加した。得られた混合物を、２３℃で３０分間攪拌した後、ろ過し、重量平均分子量が約３．９×１０^３の共重合体２０．１４部を得た。この共重合体は、次式の構造単位を有するものであり、これを重合体Ｄ２とする。 Example 6: [Synthesis of polymer D2]

15.00 parts of the compound represented by the formula (A), 9.97 parts of the compound represented by the formula (B), 3.35 parts of the compound represented by the formula (C) and the formula (I-2) 4.19 parts of the salt to be prepared (molar ratio 55: 30: 10: 5 ratio) were charged, and then 65.03 parts of acetonitrile twice as much as the total mass of all monomers were added. To the obtained mixture, 2.80 parts of azobisisobutyronitrile (a ratio of 12 mol% based on the total number of moles of all monomers) was added as an initiator, and this was heated to reflux for 6 hours. Thereafter, the reaction solution was purified and filtered by performing an operation of pouring it into a large amount of a mixed solvent of methanol and water (3: 1) for precipitation three times to obtain a copolymer.
The obtained copolymer, 97.54 parts of methyl isobutyl ketone 3 times by mass with respect to the total mass of all monomers, and p-toluenesulfonic acid at a ratio of 3% by mass with respect to the total mass of all monomers 98 parts and 97.54 parts of ion-exchanged water 3 times as much as the total mass of all monomers were added and stirred at 23 ° C. for 6 hours. Thereafter, liquid separation was performed, and 97.54 parts of ion-exchanged water was added to the obtained organic layer, followed by washing with water. This washing with water was performed 4 times. The obtained organic layer was concentrated, and 422.69 parts of n-heptane was added to the residue. The obtained mixture was stirred at 23 ° C. for 30 minutes and then filtered to obtain 20.14 parts of a copolymer having a weight average molecular weight of about 3.9 × 10 ³ . This copolymer has a structural unit of the following formula, and this is designated as polymer D2.

式（Ａ）で表される化合物１５．００部、式（Ｂ）で表される化合物９．９７部、式（Ｃ）で表される化合物３．３５部及び式（Ｉ−３）で表される塩４．６０部を、（モル比５５：３０：１０：５の割合）仕込み、次いで、全モノマーの合計質量に対して、２質量倍のアセトニトリル６５．８５部を加えた。得られた混合物に、開始剤としてアゾビスイソブチロニトリル２．８０部を（全モノマーの合計モル数に対して１２ｍｏｌ％の割合）添加し、これを６時間加熱還流した。その後、反応液を、大量のメタノールと水との混合溶媒（３：１）に注いで沈殿させる操作を３回行うことにより精製、ろ過し、共重合体を得た。
得られた共重合体と、全モノマーの合計質量に対して３質量倍のメチルイソブチルケトン９８．７８部と、全モノマーの合計質量に対して３質量％の割合でｐ−トルエンスルホン酸０．９９部と、全モノマーの合計質量に対して３質量倍のイオン交換水９８．７８部を添加し、２３℃で６時間攪拌した。その後、分液を行い、得られた有機層に、イオン交換水９８．７８部を添加し、水洗を行った。この水洗を４回行った。得られた有機層を濃縮し、残渣にｎ−ヘプタン４３０部を添加した。得られた混合物を、２３℃で３０分間攪拌した後、ろ過し、重量平均分子量が約３．９×１０^３の共重合体２４．１２部を得た。この共重合体は、次式の構造単位を有するものであり、これを重合体Ｄ３とする。 Example 7: [Synthesis of polymer D3]

15.00 parts of the compound represented by the formula (A), 9.97 parts of the compound represented by the formula (B), 3.35 parts of the compound represented by the formula (C) and the formula (I-3) 4.60 parts of the resulting salt was charged (in a molar ratio of 55: 30: 10: 5), and then 65.85 parts of acetonitrile twice the total mass of all monomers were added. To the obtained mixture, 2.80 parts of azobisisobutyronitrile (a ratio of 12 mol% based on the total number of moles of all monomers) was added as an initiator, and this was heated to reflux for 6 hours. Thereafter, the reaction solution was purified and filtered by performing an operation of pouring it into a large amount of a mixed solvent of methanol and water (3: 1) for precipitation three times to obtain a copolymer.
The obtained copolymer, 98.78 parts of methyl isobutyl ketone 3 times by mass with respect to the total mass of all monomers, and p-toluenesulfonic acid at a ratio of 3% by mass with respect to the total mass of all monomers, 99 parts and 98.78 parts of ion-exchanged water 3 times as much as the total mass of all monomers were added and stirred at 23 ° C. for 6 hours. Thereafter, liquid separation was performed, and 98.78 parts of ion-exchanged water was added to the obtained organic layer, followed by washing with water. This washing with water was performed 4 times. The obtained organic layer was concentrated, and 430 parts of n-heptane was added to the residue. The resulting mixture was stirred at 23 ° C. for 30 minutes and then filtered to obtain 24.12 parts of a copolymer having a weight average molecular weight of about 3.9 × 10 ³ . This copolymer has a structural unit of the following formula, and this is designated as polymer D3.

式（Ａ）で表される化合物１５．００部、式（Ｂ）で表される化合物９．９７部、式（Ｃ）で表される化合物３．３５部及び式（Ｉ−４）で表される塩４．９０部を、（モル比５５：３０：１０：５の割合）仕込み、次いで、全モノマーの合計質量に対して、２質量倍のアセトニトリル６６．４４部を加えた。得られた混合物に、開始剤としてアゾビスイソブチロニトリル２．８０部を（全モノマーの合計モル数に対して１２ｍｏｌ％の割合）添加し、これを６時間加熱還流した。その後、反応液を、大量のメタノールと水との混合溶媒（３：１）に注いで沈殿させる操作を３回行うことにより精製、ろ過し、共重合体を得た。
得られた共重合体と、全モノマーの合計質量に対して３質量倍のメチルイソブチルケトン９９．６６部と、全モノマーの合計質量に対して３質量％の割合でｐ−トルエンスルホン酸１．００部と、全モノマーの合計質量に対して３質量倍のイオン交換水９９．６６部を添加し、２３℃で６時間攪拌した。その後、分液を行い、得られた有機層に、イオン交換水９９．６６部を添加し、水洗を行った。この水洗を４回行った。得られた有機層を濃縮し、残渣にｎ−ヘプタン４５０部を添加した。得られた混合物を、２３℃で３０分間攪拌した後、ろ過し、重量平均分子量が約３．８×１０^３の共重合体２５．２２部を得た。この共重合体は、次式の構造単位を有するものであり、これを重合体Ｄ４とする。 Example 8: [Synthesis of polymer D4]

15.00 parts of the compound represented by the formula (A), 9.97 parts of the compound represented by the formula (B), 3.35 parts of the compound represented by the formula (C) and the formula (I-4) 4.90 parts of the salt to be prepared (molar ratio 55: 30: 10: 5 ratio) were charged, and then 66.44 parts of acetonitrile twice as much as the total mass of all monomers were added. To the obtained mixture, 2.80 parts of azobisisobutyronitrile (a ratio of 12 mol% based on the total number of moles of all monomers) was added as an initiator, and this was heated to reflux for 6 hours. Thereafter, the reaction solution was purified and filtered by performing an operation of pouring it into a large amount of a mixed solvent of methanol and water (3: 1) for precipitation three times to obtain a copolymer.
1. The obtained copolymer, 99.66 parts of methyl isobutyl ketone 3 times by mass with respect to the total mass of all monomers, and p-toluenesulfonic acid at a ratio of 3% by mass with respect to the total mass of all monomers. 00 parts and 99.66 parts of ion-exchanged water 3 times as much as the total mass of all monomers were added and stirred at 23 ° C. for 6 hours. Thereafter, liquid separation was performed, and 99.66 parts of ion-exchanged water was added to the obtained organic layer, followed by washing with water. This washing with water was performed 4 times. The obtained organic layer was concentrated, and 450 parts of n-heptane was added to the residue. The resulting mixture was stirred at 23 ° C. for 30 minutes and then filtered to obtain 25.22 parts of a copolymer having a weight average molecular weight of about 3.8 × 10 ³ . This copolymer has a structural unit of the following formula, and this is designated as polymer D4.

[Synthesis of Resin A1]
39.7 g (0.16 mol) of 2-ethyl-2-adamantyl methacrylate and 103.8 g (0.64 mol) of p-acetoxystyrene were dissolved in 265 g of isopropanol, and the solution was heated to 75 ° C. under a nitrogen atmosphere. The temperature rose. A solution prepared by dissolving 11.05 g (0.048 mol) of dimethyl 2,2-azobis (2-methylpropionate) as a radical initiator in 22.11 g of isopropanol was added dropwise to the solution. The resulting reaction solution was heated to reflux for 12 hours. After cooling, the reaction solution was poured into a large amount of methanol, and the polymer was precipitated and filtered. The obtained copolymer of 2-ethyl-2-adamantyl methacrylate and p-acetoxystyrene was 250 g (containing methanol).
250 g of the obtained copolymer and 10.3 g (0.084 mol) of 4-dimethylaminopyridine were added to 202 g of methanol and heated to reflux for 20 hours. After cooling, the reaction solution was neutralized with 7.6 g (0.126 mol) of glacial acetic acid and poured into a large amount of water to cause precipitation. The precipitated polymer was separated by filtration, dissolved in acetone, then poured into a large amount of water to precipitate and repeated and purified three times. The obtained copolymer of 2-ethyl-2-adamantyl methacrylate and p-hydroxystyrene was 95.9 g. The weight average molecular weight was about 8.6 × 10 ³ (in terms of GPC polystyrene), and the copolymerization ratio was about 20:80. This resin is referred to as Resin A1.

[Synthesis of Resin A2]
Similar to the synthesis of Resin B1, except that the amounts of 2-ethyl-2-adamantyl methacrylate and p-acetoxystyrene used were changed to 59.6 g (0.24 mol) and 90.8 g (0.56 mol). Then, 102.8 g of a copolymer of 2-ethyl-2-adamantyl methacrylate and p-hydroxystyrene was obtained. The weight average molecular weight was about 8.2 × 10 ³ (in terms of GPC polystyrene), and the copolymerization ratio was about 30:70. This resin is referred to as Resin A2.

  The following components were mixed and dissolved, and further filtered through a fluororesin filter having a pore size of 0.2 μm to prepare a resist solution. In Table 1, “-” indicates that the content is 0.

Ｂ２：トリフェニルスルホニウム２，４，６−トリイソプロピルベンゼンスルホネート
Ｂ３：ビス（シクロヘキシルスルホニウム）ジアゾメタン
＜重合体＞
Ｄ１：重合体Ｄ１
Ｄ２：重合体Ｄ２
Ｄ３：重合体Ｄ３
Ｄ４：重合体Ｄ４
＜樹脂＞
Ａ１：樹脂Ａ１
Ａ２：樹脂Ａ２
＜塩基性化合物：クエンチャー＞
Ｃ１：２，６−ジイソプロピルアニリン
Ｃ２：テトラブチルアンモニウムヒドロキシド
＜溶剤＞
プロピレングリコールモノメチルエーテルアセテート ４００．０部
プロピレングリコールモノメチルエーテル １００．０部
γ−ブチロラクトン ５．０部 <Acid generator>
I-1: Salt represented by formula (I-1) I-2: Salt B1 represented by formula (I-2)

B2: Triphenylsulfonium 2,4,6-triisopropylbenzenesulfonate B3: Bis (cyclohexylsulfonium) diazomethane <polymer>
D1: Polymer D1
D2: Polymer D2
D3: Polymer D3
D4: Polymer D4
<Resin>
A1: Resin A1
A2: Resin A2
<Basic compound: Quencher>
C1: 2,6-diisopropylaniline C2: tetrabutylammonium hydroxide <solvent>
Propylene glycol monomethyl ether acetate 400.0 parts Propylene glycol monomethyl ether 100.0 parts γ-butyrolactone 5.0 parts

(Evaluation as a resist composition for electron beams)
A silicon wafer was treated on a direct hot plate with hexamethyldisilazane at 90 ° C. for 60 seconds, and the resist solution was spin-coated so that the film thickness after drying was 0.06 μm. After application of the resist solution, pre-baking was performed for 60 seconds on a direct hot plate at the temperature shown in the “PB” column of Table 2. Each wafer on which the resist film was thus formed was exposed to a line-and-space pattern using an electron beam drawing machine [“HL-800D 50 keV” manufactured by Hitachi, Ltd.] with the exposure amount being changed stepwise.
After the exposure, post-exposure baking was performed for 60 seconds at the temperature shown in the “PEB” column of Table 2 on a hot plate, and paddle development was further performed for 60 seconds with an aqueous 2.38 wt% tetramethylammonium hydroxide solution.
The developed pattern on the silicon substrate was observed with a scanning electron microscope. The results are shown in Table 2.

  Resolution evaluation: 100 nm line and space pattern was exposed at an exposure amount of 1: 1, and the resist pattern was observed with a scanning electron microscope. Those that resolved 70 nm were marked as ◯ and those that were not resolved ×.

(Evaluation as a resist composition for EUV)
The silicon wafer was treated on a direct hot plate with hexamethyldisilazane at 90 ° C. for 60 seconds, and then the resist solution was spin-coated so that the film thickness after drying was 0.05 μm.
After applying the resist solution, it was pre-baked on a direct hot plate for 60 seconds at the temperature shown in the “PB” column of Table 3. Each wafer on which the resist film was formed in this manner was exposed to a line-and-space pattern using an EUV exposure machine while changing the exposure stepwise.
After the exposure, post-exposure baking was performed for 60 seconds at a temperature shown in the “PEB” column of Table 3 on a hot plate, and paddle development was further performed for 60 seconds with a 2.38 wt% tetramethylammonium hydroxide aqueous solution.
The developed pattern on the silicon substrate was observed with a scanning electron microscope. The results are shown in Table 3.

  Resolution evaluation: The pattern when exposed with an exposure amount at which a 50 nm line and space pattern was 1: 1 was observed with a scanning electron microscope. What resolved 40 nm was set as (circle) and what was not resolved x.

  According to the salt of the present invention, a resist pattern having excellent resolution can be produced from a resist composition containing the salt.

Claims (9)

A salt represented by the formula (I).

[In the formula (I),
R ¹ and R ² each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group.
R ³ represents a hydrogen atom or a methyl group.
X ¹ represents a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, a hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with a fluorine atom, and the divalent saturated —CH ₂ — contained in the hydrocarbon group may be replaced by —O— or —CO—.
X ² represents a divalent aromatic hydrocarbon group having 10 to 14 carbon atoms.
X ³ represents a single bond, ^{* 1} —CO—O— ^{* 2} or ^{* 1} —CO—O— (CH ₂ ) _k —CO—O— ^{* 2} .
* 1 represents a bond with —C (R ³ ) ═CH ₂ . * 2 represents a bond to ^{X 2.}
k represents an integer of 1 to 6.
Z ^{1 +} represents an organic counter ion. ] X ¹ is ^{* 1} —CO—O— ^{* 2} (* 1 represents a bond with —C (R ¹ ) (R ² ) —, and * 2 represents a bond with X ² ). The salt according to claim 1. The salt according to claim 1 or 2, wherein Z ^{1 +} is a triarylsulfonium cation.   The acid generator which contains the salt in any one of Claims 1-3 as an active ingredient.   The polymer which has a structural unit derived from the salt in any one of Claims 1-3.   A resist composition comprising: the acid generator according to claim 4; and a resin having an acid-labile group and insoluble or hardly soluble in an alkaline aqueous solution and capable of being dissolved in an alkaline aqueous solution by the action of an acid.   A resist composition comprising the polymer according to claim 5.   Furthermore, the resist composition of Claim 6 or 7 containing a basic compound. (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 using an exposure machine;
(4) A step of heating the composition layer after exposure,
(5) a step of developing the heated composition layer using a developing device;
A method for producing a resist pattern including: