JP2013053137A - Salt, resist composition and process for production of resist pattern - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resist composition which sufficiently satisfies a mask error factor (MEF) in the production of a resist pattern and a new salt included in the resist composition.SOLUTION: The salt is shown by formula (I). In formula (I), Qand Qrepresent a fluorine atom or the like. Lrepresents an aliphatic saturated hydrocarbon group or the like, wherein the methylene group in the aliphatic saturated hydrocarbon group may be replaced with an oxygen atom or the like. Lrepresents an aliphatic saturated hydrocarbon group, wherein the methylene group in the aliphatic saturated hydrocarbon group may be replaced with an oxygen atom. -NR- or the like. Rrepresents a hydrogen atom or an alkyl group. The ring W represents an alicyclic ring, wherein the methylene group composing the alicyclic ring may be replaced with an oxygen atom or the like, and the hydrogen atom included in the alicyclic ring may be replaced with a hydroxy group or the like. Rrepresents a univalent organic group including a fluorine substituted aromatic ring, wherein the organic group may have a substituent. Zrepresents an organic counter ion.

Description

  The present invention relates to a resist composition and a novel salt contained in the resist composition.

  A chemically amplified resist composition used for microfabrication of a semiconductor using a lithography technique includes an acid generator composed of a salt, a resin that is insoluble or hardly soluble in an alkaline aqueous solution, and can be dissolved in an alkaline aqueous solution by the action of an acid. And a solvent.

For example, Patent Document 1 describes a resist composition containing an acid generator composed of a salt represented by the following formula (Z1) and a resin that can be dissolved in an alkaline aqueous solution by the action of an acid.

JP 2008-74843 A

  In the conventional resist composition, the mask error factor (MEF) at the time of manufacturing the resist pattern may not be sufficiently satisfied.

［式（Ｉ）中、
Ｑ^１及びＱ^２は、同一又は相異なり、フッ素原子又は炭素数１〜６のペルフルオロアルキル基を表す。
Ｌ^１は、炭素数１〜１７の２価の脂肪族飽和炭化水素基を表し、該２価の脂肪族飽和炭化水素基を構成するメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。
Ｌ^２は、炭素数１〜６の２価の脂肪族飽和炭化水素基を表し、該２価の脂肪族飽和炭化水素基を構成するメチレン基は、酸素原子、カルボニル基又は−ＮＲ^２−に置き換わっていてもよい。
Ｒ^２は、水素原子又は炭素数１〜６のアルキル基を表す。
環Ｗは、炭素数３〜３６の脂肪族環を表し、該脂肪族環を構成するメチレン基は、酸素原子、硫黄原子、カルボニル基又はスルホニル基で置き換わっていてもよく、該脂肪族環に含まれる水素原子は、ヒドロキシ基、炭素数１〜１２のアルキル基、炭素数１〜１２のアルコキシ基、炭素数３〜１２の脂環式炭化水素基又は炭素数６〜１０の芳香族炭化水素基で置換されていてもよい。
Ｒ^１は、フッ素置換芳香環を含む１価の有機基であり、該有機基は置換基を有していてもよい。
Ｚ^＋は、有機対イオンを表す。］
〔２〕前記式（Ｉ）のＲ^１が、式（Ｒ^１−１）又は式（Ｒ^１−２）で表される有機基である、前記〔１〕記載の塩。

（＊は、Ｌ^２との結合手を表す。）
〔３〕前記式（Ｉ）の

で表される部分構造が、
式（Ｉａ１−１）、式（Ｉａ１−２）又は式（Ｉａ１−３）のいずれかで表される構造である、前記〔１〕又は〔２〕記載の塩。

［式（Ｉａ１−１）中、
アダマンタン環を構成するメチレン基は、酸素原子、硫黄原子、カルボニル基又はスルホニル基で置き換わっていてもよく、アダマンタン環に含まれる水素原子は、ヒドロキシ基、炭素数１〜１２のアルキル基、炭素数１〜１２のアルコキシ基、炭素数３〜１２の脂環式炭化水素基又は炭素数６〜１０の芳香族炭化水素基で置換されていてもよい。］

［式（Ｉａ１−２）中、
シクロヘキサン環を構成するメチレン基は、酸素原子、硫黄原子、カルボニル基又はスルホニル基で置き換わっていてもよく、シクロヘキサン環に含まれる水素原子は、ヒドロキシ基、炭素数１〜１２のアルキル基、炭素数１〜１２のアルコキシ基、炭素数３〜１２の脂環式炭化水素基又は炭素数６〜１０の芳香族炭化水素基で置換されていてもよい。］

［式（Ｉａ１−３）中、
ノルボルナン環を構成するメチレン基は、酸素原子、硫黄原子、カルボニル基又はスルホニル基で置き換わっていてもよく、ノルボルナン環に含まれる水素原子は、ヒドロキシ基、炭素数１〜１２のアルキル基、炭素数１〜１２のアルコキシ基、炭素数３〜１２の脂環式炭化水素基又は炭素数６〜１０の芳香族炭化水素基で置換されていてもよい。］
〔４〕前記式（Ｉ）のＬ^１が、
＊−ＣＯ−Ｏ−（ＣＨ_２）_ｕ−
（ｕは０〜６の整数を表す。＊は、Ｑ^１及びＱ^２と結合する炭素原子との結合手を表す。
）である、前記〔１〕〜〔３〕のいずれか記載の塩。
〔５〕前記式（Ｉ）のＬ^２が、
＊−ＣＯ−Ｏ−（ＣＨ_２）_ｖ−又は＊−Ｏ−ＣＨ_２−ＣＯ−Ｏ−
（ｖは０〜４の整数を表す。＊は、Ｗとの結合手を表す。）
である、前記〔１〕〜〔４〕のいずれか記載の塩。
〔６〕前記Ｚ^＋が、トリアリールスルホニウムカチオンである、前記〔１〕〜〔５〕のいずれか記載の塩。
〔７〕前記〔１〕〜〔６〕のいずれか記載の塩を有効成分として含有する酸発生剤。
〔８〕前記〔７〕記載の酸発生剤と、
アルカリ水溶液に不溶又は難溶であり、酸の作用によりアルカリ水溶液に溶解し得る樹脂と、
溶剤とを含有するレジスト組成物。
〔９〕さらに、塩基性化合物を含有する、前記〔８〕記載のレジスト組成物。
〔１０〕（１）前記〔８〕又は〔９〕記載のレジスト組成物を基板上に塗布する工程、
（２）塗布後の組成物を乾燥させて組成物層を形成する工程、
（３）組成物層を露光する工程、
（４）露光後の組成物層を加熱する工程、及び
（５）加熱後の組成物層を現像する工程、
を含むレジストパターンの製造方法。 In view of the above circumstances, the present inventors have intensively studied, and as a result, have reached the present invention. That is, the present invention includes the following inventions.
[1] A salt represented by the formula (I).

[In the formula (I),
Q ¹ and Q ² are the same or different and each represents a fluorine atom or a C 1-6 perfluoroalkyl group.
L ¹ represents a divalent aliphatic saturated hydrocarbon group having 1 to 17 carbon atoms, and the methylene group constituting the divalent aliphatic saturated hydrocarbon group may be replaced by an oxygen atom or a carbonyl group. .
L ² represents a divalent aliphatic saturated hydrocarbon group having 1 to 6 carbon atoms, and the methylene group constituting the divalent aliphatic saturated hydrocarbon group is an oxygen atom, a carbonyl group, or —NR ² —. It may be replaced.
R ² represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
Ring W represents an aliphatic ring having 3 to 36 carbon atoms, and a methylene group constituting the aliphatic ring may be replaced with an oxygen atom, a sulfur atom, a carbonyl group, or a sulfonyl group. The hydrogen atom contained is a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms, or an aromatic hydrocarbon having 6 to 10 carbon atoms. It may be substituted with a group.
R ¹ is a monovalent organic group containing a fluorine-substituted aromatic ring, and the organic group may have a substituent.
Z ⁺ represents an organic counter ion. ]
[2] The salt according to [1], wherein R ^{1 in the} formula (I) is an organic group represented by the formula (R ¹ -1) or the formula (R ¹ -2).

(* Represents a bond with L ² )
[3] In the formula (I)

The partial structure represented by
The salt of the above-mentioned [1] or [2], which is a structure represented by any one of formula (Ia1-1), formula (Ia1-2) or formula (Ia1-3).

[In the formula (Ia1-1),
The methylene group constituting the adamantane ring may be replaced by an oxygen atom, a sulfur atom, a carbonyl group or a sulfonyl group, and the hydrogen atom contained in the adamantane ring is a hydroxy group, an alkyl group having 1 to 12 carbon atoms, a carbon number It may be substituted with an alkoxy group having 1 to 12, an alicyclic hydrocarbon group having 3 to 12 carbon atoms, or an aromatic hydrocarbon group having 6 to 10 carbon atoms. ]

[In the formula (Ia1-2),
The methylene group constituting the cyclohexane ring may be replaced with an oxygen atom, a sulfur atom, a carbonyl group or a sulfonyl group. The hydrogen atom contained in the cyclohexane ring is a hydroxy group, an alkyl group having 1 to 12 carbon atoms, or a carbon number. It may be substituted with an alkoxy group having 1 to 12, an alicyclic hydrocarbon group having 3 to 12 carbon atoms, or an aromatic hydrocarbon group having 6 to 10 carbon atoms. ]

[In the formula (Ia1-3),
The methylene group constituting the norbornane ring may be replaced with an oxygen atom, a sulfur atom, a carbonyl group or a sulfonyl group, and the hydrogen atom contained in the norbornane ring is a hydroxy group, an alkyl group having 1 to 12 carbon atoms, a carbon number It may be substituted with an alkoxy group having 1 to 12, an alicyclic hydrocarbon group having 3 to 12 carbon atoms, or an aromatic hydrocarbon group having 6 to 10 carbon atoms. ]
[4] L ^{1 in the} formula (I) is
_{* -CO-O- (CH 2)} u -
(U represents an integer of 0 to 6. * represents a bond with a carbon atom bonded to Q ¹ and Q ² .
The salt according to any one of [1] to [3].
[5] L ^{2 in the} formula (I) is
_{* -CO-O- (CH 2)} v - or _* -O-CH 2 -CO-O-
(V represents an integer of 0 to 4. * represents a bond with W.)
The salt according to any one of [1] to [4], which is
[6] The salt according to any one of [1] to [5], wherein Z ⁺ is a triarylsulfonium cation.
[7] An acid generator containing the salt according to any one of [1] to [6] as an active ingredient.
[8] The acid generator according to [7],
A resin that is insoluble or hardly soluble in an aqueous alkaline solution and that can be dissolved in an aqueous alkaline solution by the action of an acid;
A resist composition containing a solvent.
[9] The resist composition according to [8], further containing a basic compound.
[10] (1) A step of applying the resist composition according to [8] or [9] on a substrate,
(2) The process of drying the composition after application | coating and forming a composition layer,
(3) a step of exposing the composition layer,
(4) a step of heating the composition layer after exposure, and (5) a step of developing the composition layer after heating,
A method for producing a resist pattern including:

  The resist composition containing the salt of the present invention as an acid generator can produce a resist pattern with an excellent mask error factor (MEF).

The present invention
A salt represented by the formula (I) (hereinafter sometimes referred to as “salt (I)”);
A resist composition containing the salt (I) and a resin that is insoluble or hardly soluble in an alkaline aqueous solution and can be dissolved in an alkaline aqueous solution by the action of an acid (hereinafter sometimes referred to as “resin (A)”). Hereinafter, sometimes referred to as “the present resist composition”);
The resist composition further contains a basic compound (hereinafter sometimes referred to as “basic compound (C)”) and a solvent (hereinafter sometimes referred to as “solvent (D)”). It is preferable.
A method for producing a resist pattern using the present resist composition is provided.
Hereinafter, the salt (I) will be mainly described, and the constituent components of the resist composition other than the salt (I) and the method for preparing the resist composition using them will be described. Finally, a method for producing a resist pattern using the present resist composition will be described.

In the present specification, unless otherwise specified, the following examples of substituents are applied to any chemical structural formula having the same substituents while appropriately selecting the number of carbon atoms. Among the aliphatic hydrocarbon groups, those that can be linear or branched, such as an alkyl group, include any of them. When stereoisomers exist, all stereoisomers are included. In the following examples of substituents, the numerical value attached to “C” indicates the number of carbon atoms of each group.
Further, in the present specification, "(meth) acrylic monomer", "CH ₂ = CH-CO-" or _{"CH 2 = C (CH 3)} -CO- " at least one monomer having the structure Means. Similarly, “(meth) acrylate” and “(meth) acrylic acid” mean “at least one of acrylate and methacrylate” and “at least one of acrylic acid and methacrylic acid”, respectively.

The hydrocarbon group includes an aliphatic hydrocarbon group and an aromatic hydrocarbon group.
The aliphatic hydrocarbon group includes both a chain type and a cyclic type, and includes a combination of a chain type and an alicyclic aliphatic hydrocarbon group unless otherwise defined. Further, these aliphatic hydrocarbon groups may contain a carbon-carbon double bond in a part thereof, but a saturated group (aliphatic saturated hydrocarbon group) is preferable.
Of the chain aliphatic hydrocarbon groups, the monovalent one typically includes an alkyl group.
Examples of the alkyl group include a methyl group (C ₁ ), an ethyl group (C ₂ ), a propyl group (C ₃ ), a butyl group (C ₄ ), a pentyl group (C ₅ ), a hexyl group (C ₆ ), a heptyl group ( C ₇ ), octyl group (C ₈ ), decyl group (C ₁₀ ), dodecyl group (C ₁₂ ), hexadecyl group (C ₁₄ ), pentadecyl group (C ₁₅ ), hexyldecyl group (C ₁₆ ), heptadecyl group ( C ₁₇ ) and octadecyl group (C ₁₈ ).
Examples of the divalent group of chain aliphatic hydrocarbon groups include alkanediyl groups in which one hydrogen atom has been removed from an alkyl group.
Examples of alkanediyl groups include 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 , 17-diyl group, ethane-1,1-diyl group, propane-1,1-diyl group, propane-2,2-diyl group, butane-1,3-diyl group, 2-methylpropane-1,3 - Group, 2-methylpropane-1,2-diyl, pentane-1,4-diyl group and 2-methylbutane-1,4-diyl group.

  The cyclic aliphatic hydrocarbon group (hereinafter sometimes referred to as “alicyclic hydrocarbon group”) typically means a cycloalkyl group, and includes any of the monocyclic and polycyclic groups shown below. Is also included.

As a monovalent alicyclic hydrocarbon group, a monocyclic aliphatic hydrocarbon group represents 1 hydrogen atom of a cycloalkane represented by the following formulas (KA-1) to (KA-7). It is a group that has been removed.

The polycyclic aliphatic hydrocarbon group is a group in which one hydrogen atom of a cycloalkane represented by the following formulas (KA-8) to (KA-22) is removed.

  Examples of the divalent alicyclic hydrocarbon group include groups in which two hydrogen atoms have been removed from the alicyclic hydrocarbon of formula (KA-1) to formula (KA-22).

The aliphatic hydrocarbon group may have a substituent. Such a substituent is defined each time, and examples of the substituent include a halogen atom, a hydroxy group, an alkoxy group, an alkylthio group, an acyl group, an acyloxy group, an aryl group, an aralkyl group, and an aryloxy group. .
Examples of alkoxy groups include methoxy group (C ₁ ), ethoxy group (C ₂ ), propoxy group (C ₃ ), butoxy group (C ₄ ), pentyloxy group (C ₅ ), hexyloxy group (C ₆ ), heptyl Examples thereof include an oxy group (C ₇ ), an octyloxy group (C ₈ ), a decyloxy group (C ₁₀ ), and a dodecyloxy group (C ₁₂ ).
Examples of the alkylthio group include those in which an oxygen atom of an alkoxy group is replaced by a sulfur atom, such as a methylthio group, an ethylthio group, a propylthio group, a butylthio group, a pentylthio group, a hexylthio group, a heptylthio group, an octylthio group, a decylthio group, and the like. Examples include dodecylthio group.
Examples of the acyl group include acetyl group (C ₂ ), propionyl group (C ₃ ), butyryl group (C ₄ ), valeryl group (C ₅ ), hexanoyl group (C ₆ ), heptanoyl group (C ₇ ), octanoyl group ( Includes those in which an alkyl group such as C ₈ ), decanoyl group (C ₁₀ ) and dodecanoyl group (C ₁₂ ) and a carbonyl group are bonded, and those in which an aryl group such as benzoyl group (C ₇ ) and a carbonyl group are bonded Is done.
Examples of the acyloxy group include an acetyloxy group, a propionyloxy group, a butyryloxy group, and an isobutyryloxy group.
Examples of the aralkyl group include benzyl group (C ₇ ), phenethyl group (C ₈ ), phenylpropyl group (C ₉ ), naphthylmethyl group (C ₁₁ ), and naphthylethyl group (C ₁₂ ).
Aryloxy groups include phenyloxy group (C ₆ ), naphthyloxy group (C ₁₀ ), anthryloxy group (C ₁₄ ), biphenyloxy group (C ₁₂ ), phenanthryloxy group (C ₁₄ ) and full A combination of an aryl group such as an oleenyloxy group (C ₁₃ ) and an oxygen atom is exemplified.

A typical example of the aromatic hydrocarbon group is an aryl group.
Examples of the aryl group include a phenyl group (C ₆ ), a naphthyl group (C ₁₀ ), an anthryl group (C ₁₄ ), a biphenyl group (C ₁₂ ), a phenanthryl group (C ₁₄ ), and a fluorenyl group (C ₁₃ ). .

  The aromatic hydrocarbon group may also have a substituent. Although such a substituent is defined each time, a halogen atom, an alkoxy group, an acyl group, an alkyl group, and an aryloxy group can be mentioned. Among these, the alkyl group is the same as those exemplified as the chain aliphatic hydrocarbon group, and among the substituents optionally present in the aromatic hydrocarbon group, those other than the alkyl group are aliphatic hydrocarbon groups. The same thing as what was illustrated as a substituent of is included.

［式（Ｉ）中、
Ｑ^１及びＱ^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。
Ｌ^１は、炭素数１〜１７の２価の脂肪族飽和炭化水素基を表し、該２価の脂肪族飽和炭化水素基を構成するメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。
Ｌ^２は、炭素数１〜６の２価の脂肪族飽和炭化水素基を表し、該２価の脂肪族飽和炭化水素基を構成するメチレン基は、酸素原子、カルボニル基又は−ＮＲ^２−（Ｒ^２は、水素原子又は炭素数１〜６のアルキル基を表す。）に置き換わっていてもよい。
Ｗは、炭素数３〜３６の脂肪族環基を表し、該脂肪族環基を構成するメチレン基は、酸素原子、硫黄原子、カルボニル基又はスルホニル基で置き換わっていてもよく、該脂肪族環に含まれる水素原子は、ヒドロキシ基、炭素数１〜１２のアルキル基、炭素数１〜１２のアルコキシ基、炭素数３〜１２の脂環式炭化水素基又は炭素数６〜１０の芳香族炭化水素基で置換されていてもよい。
Ｒ^１は、フッ素置換芳香環を含む１価の有機基であり、該有機基は置換基を有していてもよい。
Ｚ^＋は、有機対イオンを表す。］
本レジスト組成物に含まれる塩（Ｉ）は、新規且つ酸発生剤として有用な塩であり、本発明は塩（Ｉ）に係る発明を含む。
なお、以下の説明において、塩（Ｉ）から、有機カチオン（Ｚ^＋）を除去してなる負電荷を有するものを、場合により「スルホン酸アニオン」という。 <Salt (I)>

[In the formula (I),
Q ¹ and Q ² each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group.
L ¹ represents a divalent aliphatic saturated hydrocarbon group having 1 to 17 carbon atoms, and the methylene group constituting the divalent aliphatic saturated hydrocarbon group may be replaced by an oxygen atom or a carbonyl group. .
L ² represents a divalent aliphatic saturated hydrocarbon group having 1 to 6 carbon atoms, and the methylene group constituting the divalent aliphatic saturated hydrocarbon group is an oxygen atom, a carbonyl group, or —NR ² — ( R ² represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
W represents an aliphatic ring group having 3 to 36 carbon atoms, and the methylene group constituting the aliphatic ring group may be replaced with an oxygen atom, a sulfur atom, a carbonyl group or a sulfonyl group, The hydrogen atom contained in is a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms, or an aromatic carbon atom having 6 to 10 carbon atoms. It may be substituted with a hydrogen group.
R ¹ is a monovalent organic group containing a fluorine-substituted aromatic ring, and the organic group may have a substituent.
Z ⁺ represents an organic counter ion. ]
The salt (I) contained in the resist composition is a novel and useful salt as an acid generator, and the present invention includes an invention relating to the salt (I).
In the following description, those having a negative charge obtained by removing the organic cation (Z ⁺ ) from the salt (I) are sometimes referred to as “sulfonate anions”.

First, the sulfonate anion constituting the salt (I) will be described.
Q ¹ and Q ² each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group. Examples of the perfluoroalkyl group include those in which all the hydrogen atoms contained in the alkyl group in the alkyl group having 1 to 6 carbon atoms already exemplified are replaced with fluorine atoms. Specific examples include a trifluoromethyl 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. The perfluoroalkyl group has been described above with specific examples. Q ¹ and Q ² are each independently preferably a fluorine atom or a trifluoromethyl group, and both Q ¹ and Q ² are fluorine atoms. Further preferred.

The divalent aliphatic saturated hydrocarbon group represented by L ¹ is an alkanediyl group exemplified above in the range of 1 to 17 carbon atoms, any of the above-mentioned formulas (KA-1) to (KA-22). Examples thereof include a divalent alicyclic hydrocarbon group obtained by removing two hydrogen atoms from a cyclic hydrocarbon. The alkanediyl group may be linear or branched. Further, the divalent aliphatic saturated hydrocarbon group of L ^{1 is} a divalent aliphatic group obtained by arbitrarily combining an alkanediyl group and a divalent alicyclic hydrocarbon group as long as it has a carbon number of 17 or less. It may be a group.

The methylene group constituting the aliphatic saturated hydrocarbon group for L ¹ may be replaced with an oxygen atom or a carbonyl group. Thus, the salt (I) having a group in which a methylene group is replaced with an oxygen atom or a carbonyl group as L ¹ is preferable in view of the ease of production of the salt (I). In addition, the manufacturing method of salt (I) is mentioned later.
Specific examples of the group in which the methylene group constituting the divalent aliphatic saturated hydrocarbon group of L ¹ is replaced with an oxygen atom or a carbonyl group include, for example, the following formulas (b1-1) to (b1-7) ) Or a group represented by any of the above. L ¹ is preferably a group represented by any one of formulas (b1-1) to (b1-4), more preferably represented by formula (b1-1) or formula (b1-3). It is a group. In addition, * which shows the bond in the specific example of Formula (b1-1)-Formula (b1-7) has described the right and left according to Formula (B1). The left * is bonded to the carbon atom of C (Q ¹ ) (Q ² ), and the right * is bonded to the ring W.

式（ｂ１−１）〜式（ｂ１−７）中、
Ｌ^b2は、単結合又は炭素数１〜１５の２価の脂肪族飽和炭化水素基を表す。
Ｌ^b3は、単結合又は炭素数１〜１２の２価の脂肪族飽和炭化水素基を表す。
Ｌ^b4は、炭素数１〜１３の２価の脂肪族飽和炭化水素基を表す。但しＬ^b3及びＬ^b4の合計炭素数の上限は１３である。
Ｌ^b５は、炭素数１〜１５の２価の脂肪族飽和炭化水素基を表す。
Ｌ^b6は、単結合又は炭素数１〜１５の２価の脂肪族飽和炭化水素基を表す。
Ｌ^b7は、炭素数１〜１５の２価の脂肪族飽和炭化水素基を表す。但しＬ^b6及びＬ^b7の合計炭素数の上限は１６である。
Ｌ^b8は、炭素数１〜１４の２価の脂肪族飽和炭化水素基を表す。
Ｌ^b９は、単結合又は炭素数１〜１１の２価の脂肪族飽和炭化水素基を表す。
Ｌ^b10は、炭素数１〜１２の２価の脂肪族飽和炭化水素基を表す。但しＬ^b9及びＬ^b10の合計炭素数の上限は１２である。
Ｌ^b11及びＬ^b12は、それぞれ独立に、単結合又は炭素数１〜１３の２価の脂肪族飽和炭化水素基を表す。
Ｌ^b13は、炭素数１〜１４の２価の脂肪族飽和炭化水素基を表す。但しＬ^b11、Ｌ^b12及びＬ^b13の合計炭素数の上限は１４である。

In formula (b1-1) to formula (b1-7),
L ^b2 represents a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 15 carbon atoms.
L ^b3 represents a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 12 carbon atoms.
L ^b4 represents a divalent aliphatic saturated hydrocarbon group having 1 to 13 carbon atoms. However, the upper limit of the total carbon number of L ^b3 and L ^b4 is 13.
L ^b5 represents a divalent aliphatic saturated hydrocarbon group having 1 to 15 carbon atoms.
L ^b6 represents a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 15 carbon atoms.
L ^b7 represents a divalent aliphatic saturated hydrocarbon group having 1 to 15 carbon atoms. However, the upper limit of the total carbon number of L ^b6 and L ^b7 is 16.
L ^b8 represents a divalent aliphatic saturated hydrocarbon group having 1 to 14 carbon atoms.
L ^b9 represents a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 11 carbon atoms.
L ^b10 represents a divalent aliphatic saturated hydrocarbon group having 1 to 12 carbon atoms. However, the upper limit of the total carbon number of L ^b9 and L ^b10 is 12.
L ^b11 and L ^b12 each independently represent a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 13 carbon atoms.
L ^b13 represents a divalent aliphatic saturated hydrocarbon group having 1 to 14 carbon atoms. However, the upper limit of the total carbon number of L ^b11 , L ^b12 and L ^b13 is 14.

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.

Examples of the divalent group represented by the formula (b1-7) include the following.

Among them, L ¹ is preferably a divalent group represented by the formula (b1-1), and L ^b2 is a single bond or a C 1-6 aliphatic saturated hydrocarbon group (b1-1). More preferably, it is a divalent group represented by
_{* -CO-O- (CH 2)} u -
(U represents an integer of 0 to 6, and * represents a bond with a carbon atom of —C (Q ¹ ) (Q ² ) —)
More preferably, u is 0, ie
* -CO-O-
(* Represents a bond with a carbon atom of —C (Q ¹ ) (Q ² ) —)
It is particularly preferred that

L ² represents a divalent aliphatic saturated hydrocarbon group having 1 to 6 carbon atoms, and the methylene group constituting the divalent aliphatic saturated hydrocarbon group is an oxygen atom, a carbonyl group, or —NR ² — ( R ² represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. In consideration of the ease of manufacture of the salt (I), a methylene group constituting the aliphatic saturated hydrocarbon group, a group replaced by an oxygen atom or a carbonyl group, those having a L ² preferably.

Examples of the group in which the methylene group constituting the aliphatic saturated hydrocarbon group of L ² is replaced by an oxygen atom or a carbonyl group include * -CO—O— (CH ₂ ) _v — (v is an integer of 0 to 4). * —O—CO—, * —O—CH ₂ —CO—O—, * —O—CO—O—, * —O—CO—O—CH ₂ —, * —O—CO—. CH ₂ —O—, * —O—CH ₂ —CO—O—CH ₂ —, * —O—CO—CH ₂ —O—CH ₂ —, * —O—CH ₂ —CH ₂ —O—, etc. Among them, as L ² , * —CO—O— (CH ₂ ) _v — (v represents an integer of 0 to 4.
) Or * —O—CH ₂ —CO—O—.

で表される部分構造で表すと、式（Ｉａ１−１）、式（Ｉａ１−２）又は式（Ｉａ１−３）のいずれかで表される構造を挙げることができる。 Ring W represents an aliphatic ring having 3 to 36 carbon atoms.
The methylene group constituting the aliphatic ring of ring W may be replaced with an oxygen atom, a sulfur atom, a carbonyl group or a sulfonyl group. However, in view of the ease of production of the salt (I), the methylene group is And an aliphatic ring group which is not replaced by an oxygen atom, a sulfur atom, a carbonyl group or a sulfonyl group. Moreover, the hydrogen atom contained in the aliphatic cyclic group of W is a hydroxyl group, a C1-C12 alkyl group, a C1-C12 alkoxy group, a C3-C12 alicyclic hydrocarbon group, or carbon. The aromatic hydrocarbon group of several 6-10 may be substituted. The alkyl group, the alkoxy group, the alicyclic hydrocarbon group, and the aromatic hydrocarbon group include those already exemplified in the above-mentioned range. More preferable rings W are an adamantane ring, a cyclohexane ring and a norbornane group, and this preferable W ring is represented by the formula (I).

And a structure represented by any one of the formulas (Ia1-1), (Ia1-2), and (Ia1-3).

式（Ｉａ１−１）中、
アダマンタン環を構成するメチレン基は、酸素原子、硫黄原子、カルボニル基又はスルホニル基で置き換わっていてもよいが、該メチレン基は、ここに示す基に置換されていないものが好ましい。
該アダマンタン環に含まれる水素原子は、ヒドロキシ基、炭素数１〜１２のアルキル基、炭素数１〜１２のアルコキシ基、炭素数３〜１２の脂環式炭化水素基又は炭素数６〜１０の芳香族炭化水素基で置換されていてもよいが、アダマンタン環に含まれる水素原子は、ここに示す基に置換されていないものが好ましい。

In formula (Ia1-1),
The methylene group constituting the adamantane ring may be replaced with an oxygen atom, a sulfur atom, a carbonyl group or a sulfonyl group, but the methylene group is preferably not substituted with the group shown here.
The hydrogen atom contained in the adamantane ring is a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms, or a carbon atom having 6 to 10 carbon atoms. Although it may be substituted with an aromatic hydrocarbon group, the hydrogen atom contained in the adamantane ring is preferably not substituted with the group shown here.

式（Ｉａ１−２）中、
シクロヘキサン環を構成するメチレン基は、酸素原子、硫黄原子、カルボニル基又はスルホニル基で置き換わっていてもよいが、これらの基にメチレン基が置き換わっていないものが好ましい。
該シクロヘキサン環に含まれる水素原子は、ヒドロキシ基、炭素数１〜１２のアルキル基、炭素数１〜１２のアルコキシ基、炭素数３〜１２の脂環式炭化水素基又は炭素数６〜１０の芳香族炭化水素基で置換されていてもよいが、シクロヘキサン環に含まれる水素原子は、ここに示す基に置換されていないものが好ましい。

In formula (Ia1-2),
The methylene group constituting the cyclohexane ring may be replaced with an oxygen atom, a sulfur atom, a carbonyl group or a sulfonyl group, but those in which the methylene group is not replaced with these groups are preferred.
The hydrogen atom contained in the cyclohexane ring is a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms, or a carbon atom having 6 to 10 carbon atoms. Although it may be substituted with an aromatic hydrocarbon group, it is preferable that the hydrogen atom contained in the cyclohexane ring is not substituted with the group shown here.

式（Ｉａ１−３）中、
ノルボルナン環を構成するメチレン基は、酸素原子、硫黄原子、カルボニル基又はスルホニル基で置き換わっていてもよいが、これらの基にメチレン基が置き換わっていないものが好ましい。
該ノルボルナン環に含まれる水素原子は、ヒドロキシ基、炭素数１〜１２のアルキル基、炭素数１〜１２のアルコキシ基、炭素数３〜１２の脂環式炭化水素基又は炭素数６〜１０の芳香族炭化水素基で置換されていてもよいが、ノルボルナン環に含まれる水素原子は、ここに示す基に置換されていないものが好ましい。

In formula (Ia1-3),
The methylene group constituting the norbornane ring may be replaced with an oxygen atom, a sulfur atom, a carbonyl group or a sulfonyl group, but those in which the methylene group is not replaced with these groups are preferred.
The hydrogen atom contained in the norbornane ring is a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms, or a carbon atom having 6 to 10 carbon atoms. Although it may be substituted with an aromatic hydrocarbon group, it is preferable that the hydrogen atom contained in the norbornane ring is not substituted with the group shown here.

  Among those exemplified by showing the partial structure including the ring W, the structure represented by the formula (Ia1-1) is more preferable.

これらの具体例の中でも、式（Ｒ^１−１）〜式（Ｒ^１−１１）のいずれかで表される有機基が好ましく、式（Ｒ^１−１）〜式（Ｒ^１−６）のいずれかで表される有機基がより好ましく、式（Ｒ^１−１）又は式（Ｒ^１−２）で表される有機基がさらに好ましい。 R ^{1 in} formula (I) is a monovalent organic group containing a fluorine-substituted aromatic ring, and the organic group may have a substituent. More specific examples of R ¹ include those shown in the organic groups represented by the following formulas (R ¹ -1) to (R ¹ -16). Note that * in each of the specific examples of R ¹ is a bond to L ² .

Among these specific examples, an organic group represented by any one of formula (R ¹ -1) to formula (R ¹ -11) is preferable, and those represented by formula (R ¹ -1) to formula (R ¹ -6) The organic group represented by either is more preferable, and the organic group represented by the formula (R ¹ -1) or the formula (R ¹ -2) is more preferable.

The sulfonate anion constituting the salt (I) has been described above with reference to specific examples of Q ¹ , Q ² , L ¹ , L ² , R ¹ and W. Here, the salt (I The specific example of the sulfonate anion which comprises) is shown.

Next, the organic cation (Z ⁺ ) constituting the salt (I) will be described.
Examples of the organic cation represented by Z ⁺ include organic onium cations such as an organic sulfonium cation, an organic iodonium cation, an organic ammonium cation, a benzothiazolium cation, and an organic phosphonium cation. Among these, an organic sulfonium cation and an organic iodonium cation are preferable, and an arylsulfonium cation is more preferable.

More preferably, Z ⁺ represents an organic cation represented by any one of the following formulas (b2-1) to (b2-4) (hereinafter referred to as “cation (b2-1) according to the number of each formula: ], "Cation (b2-2)", "cation (b2-3)" and "cation (b2-4)".

In formula (b2-1) to formula (b2-4),
R ^b4 , R ^b5 and R ^b6 each independently represent an alkyl group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms or an aromatic hydrocarbon group having 6 to 18 carbon atoms, The hydrogen atom contained in the alkyl 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 is included in the alicyclic hydrocarbon group. The hydrogen atom may be substituted with a halogen atom, an acyl group having 2 to 4 carbon atoms or a glycidyloxy group, and the hydrogen atom contained in the aromatic hydrocarbon group is a halogen atom, a hydroxy group, or a carbon number of 1 It may be substituted with an aliphatic hydrocarbon group having 18 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. R ^b4 and R ^b5 may be combined to form a ring containing a sulfur atom.

The ring containing a sulfur atom which R ^b4 and R ^b5 may form together may be any of monocyclic, polycyclic, aromatic, non-aromatic, saturated and unsaturated rings. If it contains one or more sulfur atoms, it may further contain one or more sulfur atoms and / or one or more oxygen atoms. As the ring, a ring having 3 to 18 carbon atoms is preferable, and a ring having 4 to 13 carbon atoms is more preferable.

R ^b7 and R ^b8 each independently represent a hydroxy group, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.
m2 and n2 each independently represent an integer of 0 to 5. When m2 is an integer of 2 or more, the plurality of R ^b7 may be the same or different from each other. When n2 is an integer of 2 or more, the plurality of R ^b8 are the same or different from each other. May be.

R ^b9 and R ^b10 each independently represent an alkyl group having 1 to 18 carbon atoms or an alicyclic hydrocarbon group having 3 to 18 carbon atoms.
R ^b11 represents a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms.
R ^{b9 to} R ^b11 each independently represents an alkyl having 1 to 18 carbon atoms or an alicyclic hydrocarbon group having 3 to 18 carbon atoms. As for carbon number of this alkyl group, 1-12 are preferable. As for carbon number of this alicyclic hydrocarbon group, 4-12 are preferable.
R ^b12 represents an alkyl group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms, and hydrogen contained in the aromatic hydrocarbon group The atom may be substituted with an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or an alkylcarbonyloxy group having 1 to 12 carbon atoms. Good.
R ^b9 and R ^b10 and / or R ^b11 and R ^b12 are independently bonded to each other, and together with the atoms to which they are bonded, a 3- to 12-membered ring (preferably a 3- to 7-membered ring) Ring), and the methylene group contained in these rings may be replaced by an oxygen atom, a sulfur atom or a carbonyl group.

R ^{b13 to} R ^b18 each independently represent a hydroxy group, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.
L ^b11 represents an oxygen atom or a sulfur atom.
o2, p2, s2, and t2 each independently represents an integer of 0 to 5.
q2 and r2 each independently represents an integer of 0 to 4.
u2 represents 0 or 1.
When o2 is 2 or more, the plurality of R ^b13 may be the same or different. When p2 is 2 or more, the plurality of R ^b14 may be the same or different. When s2 is 2 or more, The plurality of R ^b15 may be the same or different, and when t2 is 2 or more, the plurality of R ^b15 may be the same or different.

The alkylcarbonyloxy group for R ^b12 is a group in which the acyl group already exemplified and an oxygen atom are bonded.

Preferred examples of the alkyl group ^{represented by} R ^{b9 to} R ^b12 include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, and an octyl group. And 2-ethylhexyl group.
Preferable examples of the alicyclic hydrocarbon group represented by R ^{b9 to} R ^b11 include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclodecyl group, and an isobornyl group.
Preferred examples of the aromatic hydrocarbon group for R ^b12 include phenyl group, 4-methylphenyl group, 4-ethylphenyl group, 4-tert-butylphenyl group, 4-cyclohexylphenyl group, 4-methoxyphenyl group, And biphenylyl and naphthyl groups.
A group in which an aromatic hydrocarbon group of R ^b12 and an alkyl group are bonded is typically an aralkyl group.

Examples of the ring formed by combining the combination of R ^b9 and R ^b10 include, for example, a thiolane-1-ium ring (tetrahydrothiophenium ring), a thian-1-ium ring, and a 1,4-oxathian-4-ium ring. Etc.
Examples of the ring formed by combining the combination of R ^b11 and R ^b12 include an oxocycloheptane ring, an oxocyclohexane ring, an oxonorbornane ring, and an oxoadamantane ring.

  Specific examples of the organic cation represented by each of the formulas (b2-1) to (b2-4) include cations described in JP2010-204646A.

式（ｂ２−１−１）中、
Ｒ^b19、Ｒ^b20及びＲ^b21は、それぞれ独立に、ハロゲン原子（より好ましくはフッ素原子）、ヒドロキシ基、炭素数１〜１８の脂肪族炭化水素基又は炭素数１〜１２のアルコキシ基を表す。また、Ｒ^b19〜Ｒ^b21から選ばれる２つが一緒になってヘテロ原子を有してもよい環を形成してもよい。
この脂肪族炭化水素基の炭素数は１〜１２であると好ましく、炭素数１〜１２のアルキル基及び炭素数４〜１８の脂環式炭化水素基がより好ましく、さらには置換基として、ハロゲン原子、ヒドロキシ基、炭素数１〜１２のアルコキシ基、炭素数６〜１８の芳香族炭化水素基、炭素数２〜４のアシル基又はグリシジルオキシ基を有していてもよい。
Ｒ^b19〜Ｒ^b21のアルキル基は、炭素数１〜１２の範囲が好ましく、当該アルキル基に含まれる水素原子は、ヒドロキシ基、炭素数１〜１２のアルコキシ基又は炭素数６〜１８の芳香族炭化水素基に置換されていてもよい。
ｖ２、ｗ２及びｘ２は、それぞれ独立に０〜５の整数（好ましくは０又は１）を表す。
ｖ２が２以上のとき、複数のＲ^b19は同一でも異なっていてもよく、ｗ２が２以上のとき、複数のＲ^b20は同一でも異なっていてもよく、ｘ２が２以上のとき、複数のＲ^b21は同一でも異なっていてもよい。
なかでも、Ｒ^b19、Ｒ^b20及び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。 Among the exemplified organic cations, the cation (b2-1) is preferable, and an organic cation represented by the following formula (b2-1-1) [hereinafter, referred to as “cation (b2-1-1)” may be used. ], More preferably a triphenylsulfonium cation (in formula (b2-1-1), v2 = w2 = x2 = 0) or a tolylsulfonium cation (in formula (b2-1-1), v2 = w2 = X2 = 1, and R ^b19 , R ^b20 and R ^b21 are all methyl groups).

In formula (b2-1-1),
R ^b19 , R ^b20 and R ^b21 each independently represent a halogen atom (more preferably a fluorine atom), a hydroxy group, an aliphatic hydrocarbon group having 1 to 18 carbon atoms or an alkoxy group having 1 to 12 carbon atoms. It is also possible to form two of which may have a hetero atom together ring selected from R ^b19 to R ^b21.
The aliphatic hydrocarbon group preferably has 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 12 carbon atoms and an alicyclic hydrocarbon group having 4 to 18 carbon atoms. You may have an atom, a hydroxy group, a C1-C12 alkoxy group, a C6-C18 aromatic hydrocarbon group, a C2-C4 acyl group, or a glycidyloxy group.
The alkyl group of R ^{b19 to} R ^b21 preferably has 1 to 12 carbon atoms, and the hydrogen atom contained in the alkyl group is a hydroxy group, an alkoxy group having 1 to 12 carbon atoms or an aromatic group having 6 to 18 carbon atoms. It may be substituted with a hydrocarbon group.
v2, w2 and x2 each independently represent an integer of 0 to 5 (preferably 0 or 1).
When v2 is 2 or more, a plurality of R ^b19 may be the same or different. When w2 is 2 or more, a plurality of R ^b20 may be the same or different. When x2 is 2 or more, a plurality of R ^{b19 b21} may be the same or different.
Among them, R ^b19 , R ^b20 and R ^b21 are preferably each independently a halogen atom (more preferably a fluorine atom), a hydroxy group, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. It is a group.

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

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

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

As mentioned above, although salt (I) was divided into the sulfonate anion and organic cation which comprise it, the said salt (I) is a combination of a sulfonate anion and an organic cation. These sulfonate anions and organic cations can be arbitrarily combined.
Specific examples of this combination include those listed in Tables 1 to 3 below.

Among the salts (I) shown in combinations in Tables 1 to 3, more preferable salts (I) are specifically shown as follows.

（式中、全ての符号は、それぞれ前記と同義である。）
この反応の溶媒としては、アセトニトリルなどが用いられる。 Subsequently, L ¹ is * —CO—O— (* represents a bond with —C (Q ¹ ) (Q ² ) —), and L ² is * —CO—O— (* represents An embodiment of the method for producing the salt (I) will be described with reference to the salt (I) as an example. This salt (I) can be produced, for example, by reacting a compound represented by the formula (b1-a) with a compound represented by the formula (b1-b) in a solvent. This reaction is shown in the form of a reaction formula as follows.

(Wherein all symbols are as defined above)
As a solvent for this reaction, acetonitrile or the like is used.

この反応の溶媒としては、アセトニトリルなどが用いられる。式（ｂ１−ｃ）で表される化合物は、例えば、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。 The compound represented by the formula (b1-a) can be obtained by reacting the compound represented by the formula (b1-c) with the compound represented by the formula (b1-d) in a solvent. it can. This reaction is shown in the form of a reaction formula as follows.

As a solvent for this reaction, acetonitrile or the like is used. The compound represented by the formula (b1-c) can be synthesized, for example, by the method described in JP 2008-127367 A.

式（ｂ２−ｆ）で表される化合物としては、例えば、以下で表される化合物などが挙げられる。

The salt represented by the formula (b1-b) can be obtained by reacting the compound represented by the formula (b1-e) with the compound represented by the formula (b1-f) in a solvent. . As the solvent, chloroform or the like is used.

As a compound represented by a formula (b2-f), the compound represented by the following etc. is mentioned, for example.

式（ｂ１−ｇ）で表される化合物としては、例えば、以下で表される化合物などが挙げられる。

The compound represented by the formula (b1-e) can be obtained by reacting the compound represented by the formula (b1-g) with the compound represented by the formula (b1-d) in a solvent. it can. As the solvent, chloroform or the like is used.

Examples of the compound represented by the formula (b1-g) include compounds represented by the following.

式（ｂ１−ｈ）で表される化合物としては、例えば、以下で表される化合物などが挙げられる。

The compound represented by the formula (b1-g) can also be obtained, for example, by reducing the compound represented by the formula (b1-h). The reduction is preferably performed in a solvent, and acetonitrile, water and the like are used as the solvent. As the reducing agent, sodium borohydride or the like is used.

Examples of the compound represented by the formula (b1-h) include compounds represented by the following.

<Acid generator other than salt (I)>
The acid generator contained in the resist composition is characterized by containing a salt (I) as an active ingredient, and the salt (I) may be used alone or in combination of two or more. Good. Moreover, the acid generator contained in the resist composition may further contain a known acid generator other than the salt (I). The acid generator other than the salt (I) may be an ionic acid generator or a nonionic generator. The ionic acid generator includes both a cation and an anion constituting the salt (I). Is different, of course
Even an ionic acid generator comprising a combination of the same cation as the organic cation constituting the salt (I) and a known anion other than the sulfonate anion constituting the salt (I),
It may be an ionic acid generator composed of a combination of the same anion as the sulfonate anion constituting the salt (I) and a known cation other than the organic cation constituting the salt (I).
Hereinafter, the acid generator other than the salt (I) contained in the resist composition is sometimes referred to as “acid generator (B)”.

As an acid generator (B), what is represented by either of Formula (B1-1)-Formula (B1-20) is mentioned, for example. Among them, those containing a triphenylsulfonium cation and a tolylsulfonium cation are preferable. Formula (B1-1), Formula (B1-2), Formula (B1-3), Formula (B1-6), and Formula (B1-7) And salts represented by formula (B1-11), formula (B1-12), formula (B1-13) and formula (B1-14), respectively.

  The content of the salt (I) is preferably 10 parts by mass or more, more preferably 30 parts by mass or more with respect to 100 parts by mass of the total amount of the acid generator. Substantially only the salt (I) can be used as an acid generator. Moreover, in order to adjust the characteristic which concerns on this resist composition, you may use an acid generator (B) as mentioned above.

<This resist composition>
The resist composition contains an acid generator containing salt (I) as an active ingredient. Moreover, this resist composition contains resin (A) other than an acid generator. In addition, an additive such as a basic compound called a quencher in the art (hereinafter sometimes referred to as “basic compound (C)”) and a solvent (D) may be contained as necessary. Hereinafter, in addition to the acid generator, the resin (A) and the additive such as the basic compound (C) and the solvent (D) contained in the resist composition will be sequentially described. In the following description, in describing the composition of the present resist composition, the composition obtained by removing the solvent from the present resist composition may be defined as “solid content” of the present resist composition. The content ratio of the solid content to the total mass of the resist composition can be measured by a known analysis means such as liquid chromatography and gas chromatography.

<Resin (A)>
In order to produce a resist pattern by the action of an acid generated from an acid generator, the resin (A) contained in the resist composition is insoluble or hardly soluble in an alkaline aqueous solution as described above. It is preferable that it has a characteristic that it becomes soluble in an alkaline aqueous solution by action (hereinafter referred to as “acid action characteristic” in some cases). Note that “can be dissolved in an alkaline aqueous solution by the action of an acid” means “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”. Means.

The resin (A) having acid action characteristics has an acid labile group (hereinafter, sometimes referred to as “acid labile group”) in its molecule. Such a resin (A) is a monomer having an acid labile group (hereinafter, this monomer is sometimes referred to as “monomer (a1)”, and the structural unit derived from the monomer (a1) is referred to as “structural unit (a1)”. Can be produced by polymerization.
In producing the resin (A) having acid action characteristics, the monomer (a1) may be used alone, or two or more kinds may be used in combination.

<Acid labile group>
The “acid labile group” means a group that has a leaving group, and the leaving group is removed by 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 a group represented by the formula (1) and a group represented by the formula (2).

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

［式（２）中、Ｒ^ａ１’及びＲ^ａ２’は、それぞれ独立に、水素原子又は炭素数１〜１２の炭化水素基を表し、Ｒ^ａ３’は、炭素数１〜２０の炭化水素基を表すか、Ｒ^ａ２’及びＲ^ａ３’は互いに結合して炭素数２〜２０の２価の炭化水素基を形成し、該１価の炭化水素基及び該２価の炭化水素基に含まれるメチレン基は、酸素原子又は硫黄原子で置き換わっていてもよい。＊は結合手を表す。］

In Expression (1), R ^a1 ~R ^a3 each independently represent a cycloaliphatic hydrocarbon radical of the alkyl group or 3 to 20 carbon atoms having 1 to 8 carbon atoms, R ^a1 and R ^a2 are each Bonding to form a divalent hydrocarbon group having 2 to 20 carbon atoms. * Represents a bond. ]

[In formula (2), R ^{a1 ′} and R ^{a2 ′} each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, and R ^{a3 ′} represents a hydrocarbon group having 1 to 20 carbon atoms. R ^{a2 ′} and R ^{a3 ′} are bonded to each other to form a divalent hydrocarbon group having 2 to 20 carbon atoms, and methylene contained in the monovalent hydrocarbon group and the divalent hydrocarbon group. The group may be replaced with an oxygen atom or a sulfur atom. * Represents a bond. ]

式（１）における脂環式炭化水素基は、好ましくは炭素数３〜１６である。 ^Examples of the alkyl group represented by R ^{a1 to} R ^a3 include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, and an octyl group.
The alicyclic hydrocarbon group may be monocyclic or polycyclic, and examples of the monocyclic alicyclic hydrocarbon group include a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. And cycloalkyl groups such as groups. Examples of the polycyclic saturated hydrocarbon group include decahydronaphthyl group, adamantyl group, norbornyl group, and the following groups.

The alicyclic hydrocarbon group in formula (1) preferably has 3 to 16 carbon atoms.

２価の炭化水素基数は、好ましくは炭素数３〜１２である。 In the case where R ^a1 and R ^a2 are bonded to each other to form a divalent hydrocarbon group, examples of the —C (R ^a1 ) (R ^a2 ) (R ^a3 ) group include the following groups.

The number of divalent hydrocarbon groups is preferably 3 to 12 carbon atoms.

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

Examples of the hydrocarbon group for R ^{a1 ′} and R ^{a2 ′} include an alkyl group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group.
Aromatic hydrocarbon groups include phenyl, naphthyl, anthryl, p-methylphenyl, p-tert-butylphenyl, p-adamantylphenyl, tolyl, xylyl, cumenyl, mesityl, biphenyl Groups, phenanthryl groups, 2,6-diethylphenyl groups, aryl groups such as 2-methyl-6-ethylphenyl, and the like.

Preferably, at least one of R ^{a1 ′} and R ^{a2 ′} is a hydrogen atom.
Specific examples of the group represented by the formula (2) include the following groups.

  The monomer (a1) having an acid labile group is preferably a monomer having an alicyclic hydrocarbon group having 5 to 20 carbon atoms. If a resin obtained by polymerizing the monomer (a1) having a bulky structure such as an alicyclic hydrocarbon group is used, the resolution of the resist can be improved.

  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 ( (Meth) acrylic monomer having 1). Here, (meth) acryl represents acryl and / or methacryl.

  As the (meth) acrylic monomer having an acid labile group and an alicyclic hydrocarbon group, a monomer represented by the formula (a1-1) and a monomer represented by the formula (a1-2) are preferable. It is done. 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−を表し、ｋ１は１〜７の整数を表し、＊は−ＣＯ−との結合手を表す。
Ｒ^a4及びＲ^a5は、それぞれ独立に、水素原子又はメチル基を表す。
Ｒ^a6及びＲ^a7は、それぞれ独立に、炭素数１〜８のアルキル基又は炭素数３〜１０の脂環式炭化水素基を表す。
ｍ１は０〜１４の整数を表す。
ｎ１は０〜１０の整数を表す。
ｎ１’は０〜３の整数を表す。］

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

脂環式炭化水素基は、好ましくは炭素数８以下、より好ましくは６以下である。
ｍ１は、好ましくは０〜３の整数、より好ましくは０又は１である。
ｎ１は、好ましくは０〜３の整数、より好ましくは０又は１である。
ｎ１’は、好ましくは０又は１である。 In formula (a1-1) and formula (a1-2), L ^a1 and L ^a2 are preferably —O— or * —O— (CH ₂ ) _k1 —CO—O—, more preferably. -O-. k1 is preferably an integer of 1 to 4, more preferably 1.
R ^a4 and R ^a5 are preferably methyl groups.
^Examples of the alkyl group for R ^a6 and R ^a7 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 alkyl group for R ^a6 and R ^a7 preferably has 6 or less carbon atoms.
The alicyclic hydrocarbon group for R ^a6 and R ^a7 may be monocyclic or polycyclic, and examples of the monocyclic alicyclic hydrocarbon group include a cyclopentyl group, a cyclohexyl group, Examples thereof include cycloalkyl groups such as cycloheptyl group and cyclooctyl group. Examples of the polycyclic saturated hydrocarbon group include decahydronaphthyl group, adamantyl group, norbornyl group, and the following groups.

The alicyclic 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.
n1 ′ is preferably 0 or 1.

Examples of the monomer represented by the formula (a1-1) include monomers described in JP 2010-204646 A. A monomer represented by any one of formula (a1-1-1) to formula (a1-1-8) is preferred, and represented by any one of formula (a1-1-1) to formula (a1-1-4). More preferred is a monomer.

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

  When the resin (A) has the structural unit (a1-1) and / or the structural unit (a1-2), the total content thereof is based on the total structural unit (100 mol%) of the resin (A). The range of 10 to 95 mol% is preferable, the range of 15 to 90 mol% is more preferable, the range of 20 to 85 mol% is more preferable, and the range of 20 to 60 mol% is particularly preferable. When the structural unit (a1) has a structural unit (a1) having an adamantyl group (particularly preferably, the structural unit (a1-1)), the total of the structural units (a1) in the resin (A) The structural unit (a1) having an adamantyl group is preferably 15 mol% or more with respect to (100 mol%). With such a content ratio, the resin (A) having the structural unit (a1) having an adamantyl group tends to have good dry etching resistance of a resist pattern produced from the resist composition containing the resin (A). There is. In addition, in order to make the total content rate of a structural unit (a1-1) and / or a structural unit (a1-2) into the above-mentioned range, when manufacturing resin (A), it is with respect to the usage-amount of all monomers. What is necessary is just to adjust the usage-amount of the monomer which induces | guides | derives a structural unit (a1-1) and / or a structural unit (a1-2).

  The structural unit (a1-1) and the structural unit (a1-2), which are preferable structural units (a1), have been described above. However, the resin (A) has a structural unit (a1) other than these. May be. Hereinafter, the structural unit (a1) other than the structural unit (a1-1) and the structural unit (a1-2) will be described by showing a monomer that induces the structural unit (a1).

［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−ＣＯＯＲ^a13で表される基を表し、Ｒ^a13は、炭素数１〜８の脂肪族炭化水素基を表し、該脂肪族炭化水素基に含まれる水素原子はヒドロキシ基などで置換されていてもよく、該脂肪族炭化水素基を構成するメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。Ｒ^a10、Ｒ^a11及びＲ^a12は、それぞれ独立に、炭素数１〜１２の脂肪族炭化水素基を表すか、或いはＲ^a10及びＲ^a11は互いに結合して環を形成している。該脂肪族炭化水素基及に含まれる水素原子はヒドロキシ基などで置換されていてもよく、該脂肪族炭化水素基を構成するメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。］ The resin (A) may have a structural unit (a1) derived from a monomer represented by the following formula (a1-3) (hereinafter sometimes referred to as “monomer (a1-3)”). Good. In the resin (A) having the structural unit (a1) derived from the monomer (a1-3), the structural unit (a1) contains a rigid norbornane ring in the main chain of the resin (A). This resist composition containing such a resin (A) tends to be able to produce a resist pattern having excellent dry etching resistance.

[In the formula (a1-3),
R ^a9 represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 3 carbon atoms which may have a substituent (for example, a hydroxy group), a carboxy group, a cyano group, or a group represented by —COOR ^a13. , R ^a13 represents an aliphatic hydrocarbon group having 1 to 8 carbon atoms, and a hydrogen atom contained in the aliphatic hydrocarbon group may be substituted with a hydroxy group or the like, and constitutes the aliphatic hydrocarbon group The methylene group may be replaced by an oxygen atom or a carbonyl group. R ^a10 , R ^a11 and R ^a12 each independently represents an aliphatic hydrocarbon group having 1 to 12 carbon atoms, or R ^a10 and R ^a11 are bonded to each other to form a ring. The hydrogen atom contained in the aliphatic hydrocarbon group may be substituted with a hydroxy group or the like, and the methylene group constituting the aliphatic hydrocarbon group may be replaced with an oxygen atom or a carbonyl group. ]

The aliphatic hydrocarbon group which may have a substituent of R ^a9 is typically an alkyl group which may have a substituent, and among these alkyl groups, an alkyl having no substituent The group includes those already exemplified in the range of 1 to 8 carbon atoms. Examples of the substituent, particularly the aliphatic hydrocarbon group (alkyl group) having a hydroxy group include 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.

The aliphatic hydrocarbon groups of R ^{a10 to} R ^a12 are also typically alkyl groups, and specific examples thereof are the same as those of R ^a9 . The ring formed by combining R ^a10 and R ^a11 together with the carbon atom to which they are bonded includes a cyclohexyl ring and an adamantyl ring.

As a monomer (a1-3), what was described in Unexamined-Japanese-Patent No. 2010-204646 is used, for example. Among these, a monomer represented by any of the following formula (a1-3-1), formula (a1-3-2), formula (a1-3-3) and formula (a1-3-4) The monomer represented by formula (a1-3-2) or (a1-3-4) is more preferred, and the monomer represented by formula (a1-3-2) is more preferred.

  When the resin (A) has a structural unit derived from the monomer (a1-3), the content is preferably in the range of 10 to 95 mol% with respect to the total structural unit of the resin (A). The range of 90 mol% is more preferable, and the range of 20 to 85 mol% is more preferable.

［式（ａ１−４）中、
Ｒ¹⁰は、ハロゲン原子を有してもよい炭素数１〜６のアルキル基、水素原子又はハロゲン原子を表す。
ｌ^ａは０〜４の整数を表す。
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し、ｌ^ａが２以上である場合、複数のＲ¹¹は互いに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、置換基を有していてもよい炭素数１〜１７の脂肪族炭化水素基又は単結合を表し、該脂肪族炭化水素基を構成するメチレン基は、酸素原子、硫黄原子、カルボニル基、スルホニル基又は−Ｎ（Ｒ^ｃ）−（ただし、Ｒ^ｃは、水素原子又は炭素数１〜６のアルキル基を表す）で表される基に置き換わっていてもよい。
Ｙ^a3は、置換基を有していてもよい炭素数１〜１８の炭化水素基を表す。］ The resin (A) may have a structural unit (a1) derived from a monomer represented by the following formula (a1-4) (hereinafter sometimes referred to as “monomer (a1-4)”).

[In the formula (a1-4),
R ¹⁰ represents an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, a hydrogen atom or a halogen atom.
l ^a represents an integer of 0 to 4;
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. In the case where l ^a is 2 or more, a plurality of R ¹¹ may be the same as or different from each other.
R ¹² and R ¹³ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms.
X ^a2 represents an ^optionally substituted aliphatic hydrocarbon group having 1 to 17 carbon atoms or a single bond, and the methylene group constituting the aliphatic hydrocarbon group includes an oxygen atom, a sulfur atom, a carbonyl A group, a sulfonyl group, or a group represented by —N (R ^c ) — (wherein R ^c represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms) may be substituted.
Y ^a3 represents an ^optionally substituted hydrocarbon group having 1 to 18 carbon atoms. ]

Among “an alkyl group having 1 to 6 carbon atoms which may have a halogen atom”, the alkyl group includes those already exemplified in the range of 1 to 6 carbon atoms. As the alkyl group having a halogen atom, an alkyl group having a fluorine atom is preferable. For example, a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group, a perfluorotert- Examples thereof include a butyl group, a perfluoropentyl group, and a perfluorohexyl group. Among these, as R < ¹⁰ >, a C1-C4 alkyl group is preferable, a methyl group and an ethyl group are more preferable, and a methyl group is especially preferable.
The alkoxy group of R ¹¹ includes those already exemplified in the range of 1 to 6 carbon atoms. Among them, an alkoxy group having 1 to 4 carbon atoms is preferable, a methoxy group and an ethoxy group are more preferable, and a methoxy group is particularly preferable. .
The acyl group and acyloxy group of R ¹¹ include those already exemplified in the range of 2 to 4 carbon atoms.
The hydrocarbon groups of R ¹² and R ¹³ are those having 1 to 12 carbon atoms, and the hydrocarbon group of Y ^a3 is the aliphatic hydrocarbon group exemplified above in the range of 1 to 18 carbon atoms. Contains any of the aromatic hydrocarbon groups.
The aliphatic hydrocarbon group of X ^a2 is a divalent chain hydrocarbon group, a divalent alicyclic hydrocarbon group, or a divalent group in which a chain hydrocarbon group and an alicyclic hydrocarbon group are combined. And groups obtained by appropriately combining the groups already exemplified in the range of 1 to 17 carbon atoms.

As a monomer (a1-4), the monomer described in Unexamined-Japanese-Patent No. 2010-204646 is mentioned, for example. Any monomer represented by any of the following formulas (a1-4-1) to (a1-4-7) is preferred, and the formulas (a1-4-1) to (a1-4-5) are preferred. A monomer represented by any of the above is more preferred.

  When the resin (A) has a structural unit derived from the monomer (a1-4), the content is preferably in the range of 10 to 95 mol% with respect to the total structural unit of the resin (A). The range of mol% is more preferable, and the range of 20 to 85 mol% is more preferable.

式（ａ１−５）中、
Ｒ^３１は、ハロゲン原子を有してもよい炭素数１〜６のアルキル基、水素原子又はハロゲン原子を表す。
Ｌ^３〜Ｌ^５は、酸素原子、硫黄原子又は＊−Ｏ−（ＣＨ₂）_k4−ＣＯ−Ｏ−で表される基を表す。ここで、ｋ４は１〜７の整数を表し、＊はカルボニル基（−ＣＯ−）との結合手である。
Ｚ^１’は、単結合又は炭素数１〜６のアルカンジイル基であり、該アルカンジイル基中に含まれるメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。
ｓ１及びｓ１’は、それぞれ独立して、０〜４の整数を表す。 As the other monomer (a1), for example, a monomer represented by the formula (a1-5) (hereinafter sometimes referred to as “monomer (a1-5)”) may be used.

In formula (a1-5),
R ³¹ represents a C 1-6 alkyl group which may have a halogen atom, a hydrogen atom or a halogen atom.
L ^{3 to} L ⁵ represent an oxygen atom, a sulfur atom, or a group represented by * —O— (CH ₂ ) _k4 —CO—O—. Here, k4 represents an integer of 1 to 7, and * is a bond with a carbonyl group (—CO—).
Z ^{1 ′} is a single bond or an alkanediyl group having 1 to 6 carbon atoms, and the methylene group contained in the alkanediyl group may be replaced with an oxygen atom or a carbonyl group.
s1 and s1 ′ each independently represents an integer of 0 to 4.

In formula (a1-5), R ³¹ is preferably a hydrogen atom, a methyl group, or a trifluoromethyl group.
L ⁵ is preferably an oxygen atom.
One of L ³ and L ⁴ is preferably an oxygen atom and the other is a sulfur atom.
s1 is preferably 1.
s1 ′ is preferably an integer of 0 to 2.
Z ^{1 ′} is preferably a single bond or * —CH ₂ —CO—O—.

Examples of the monomer (a1-5) include the following monomers.

  When the resin (A) has a structural unit derived from the monomer (a1-5), the content thereof is in the range of 1 to 95 mol% with respect to all the structural units (100 mol%) of the resin (A). Is preferable, the range of 3-90 mol% is more preferable, and the range of 5-85 mol% is further more preferable.

<Acid stable structural unit>
Resin (A) is a structural unit not having an acid labile group in addition to a structural unit (a1) having an acid labile group (hereinafter, sometimes referred to as “acid stable structural unit”). A monomer that can be derived is sometimes referred to as an “acid-stable monomer”. In the resin (A), the acid stable structural unit may have only one type, or may have a plurality of types.

  When the resin (A) has an acid stable structural unit, the content ratio of the acid stable structural unit may be determined based on the content ratio of the structural unit (a1). The ratio of the content ratio of the structural unit (a1) and the content ratio of the acid-stable structural unit is represented by [structural unit (a1)] / [acid-stable structural unit], and preferably 10 to 80 mol% / 90 to It is 20 mol%, More preferably, it is 20-60 mol% / 80-40 mol%. If it does in this way, there exists a tendency for the dry etching tolerance of the resist pattern obtained from this resist composition containing resin (A) to become still better.

Next, a preferable thing is demonstrated among an acid stable structural unit.
The acid stable structural unit is preferably a structural unit having a hydroxy group or a lactone ring. An acid stable structural unit having a hydroxy group (hereinafter sometimes referred to as “acid stable structural unit (a2)”) and / or an acid stable structural unit having a lactone ring (hereinafter referred to as “acid stable structural unit (a3)”). The resin (A) having a composition) may be a coating film formed on the substrate or a composition layer obtained from the coating film when the resist composition containing the resin (A) is applied to the substrate. However, since it has excellent adhesion to the substrate, a resist pattern can be produced with good resolution. In addition, the manufacturing method of the resist pattern using this resist composition here is mentioned later. First, the acid stable structural unit (a2) and the acid stable structural unit (a3) suitable as the acid stable structural unit will be described with specific examples.

<Acid stable structural unit (a2)>
When the acid-stable structural unit (a2) is introduced into the resin (A), a suitable acid-stable structure is used depending on the type of exposure source when producing a resist pattern from the resist composition containing the resin (A). The unit (a2) can be selected. That is, when this resist composition is used for exposure using a KrF excimer laser (wavelength: 248 nm) as an exposure source, or exposure using a high energy beam such as an electron beam or EUV light as an exposure source, an acid stable structural unit ( As a2), it is preferable to introduce an acid stable structural unit (a2-0) having a phenolic hydroxy group into the resin (A).
When using exposure using a short wavelength ArF excimer laser (wavelength: 193 nm) as an exposure source, an acid stable structural unit represented by the formula (a2-1) described later is used as a resin ( It is preferable to introduce into A). Thus, each of the acid stable structural units (a2) possessed by the resin (A) can be selected according to the exposure source used for producing the resist pattern, but the acid stable structural units possessed by the resin (A) ( a2) may have only one type of acid stable structural unit (a2) suitable for the type of exposure source, and two or more types of acid stable structural unit (a2) suitable for the type of exposure source. Or an acid stable structural unit (a2) suitable for the type of exposure source and a combination of other acid stable structural units (a2).

式（ａ２−１）中、
Ｌ^a3は、酸素原子又は＊−Ｏ−（ＣＨ₂）_k2−ＣＯ−Ｏ−（ｋ２は１〜７の整数を表す。）を表し、＊はカルボニル基（−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。 One specific example of the acid stable structural unit (a2) is one represented by the following formula (a2-1) (hereinafter sometimes referred to as “acid stable structural unit (a2-1)”).

In formula (a2-1),
L ^a3 represents an oxygen atom or * —O— (CH ₂ ) _k2 —CO—O— (k2 represents an integer of 1 to 7), and * represents a bond with a carbonyl group (—CO—). Represent.
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.

L ^a3 is preferably an oxygen atom or a group represented by * —O— (CH ₂ ) _k2 —CO—O—, wherein k2 is an integer of 1 to 4, and more preferably an oxygen atom or * —O—CH ₂ —CO—O—, and more preferably an oxygen atom.
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 structural unit (a2-1), the following are mentioned, for example.

  As described above, the exemplified acid stable structural unit (a2-1) is derived from, for example, an acid stable monomer described in JP 2010-204646 A. Among these, the acid stable structural unit represented by any one of formula (a2-1-1), formula (a2-1-2), formula (a2-1-3) and formula (a2-1-4) Are more preferable, and an acid stable structural unit represented by the formula (a2-1-1) or (a2-1-3) is more preferable.

  When the resin (A) has a structural unit derived from the monomer represented by the formula (a2-1), the content ratio is usually 3 to the total structural unit (100 mol%) of the resin (A). It is 45 mol%, preferably 5 to 40 mol%, more preferably 5 to 35 mol%.

式（ａ２−０）中、
Ｒ^a30は、ハロゲン原子を有してもよい炭素数１〜６のアルキル基、水素原子又はハロゲン原子を表す。
Ｒ^a31は、ハロゲン原子、ヒドロキシ基、炭素数１〜６のアルキル基、炭素数１〜６のアルコキシ基、炭素数２〜４のアシル基、炭素数２〜４のアシルオキシ基、アクリロイルオキシ基又はメタクリロイルオキシ基を表す。
ｍａは０〜４の整数を表す。ｍａが２以上の整数である場合、複数のＲ^a31は同一でも異なっていてもよい。 Next, the acid stable structural unit which has a phenolic hydroxy group among the acid stable structural units which have a hydroxy group is demonstrated. The acid stable structural unit is preferably one represented by the following formula (a2-0) (hereinafter sometimes referred to as “acid stable structural unit (a2-0)”).

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

Specific examples of the “alkyl group having 1 to 6 carbon atoms” in the “alkyl group having 1 to 6 carbon atoms which may have a halogen atom” for R ^a30 include those already exemplified in this range. . The “C 1-6 alkyl group having a halogen atom” is one in which at least a part of the hydrogen atoms contained in the C 1-6 alkyl group is substituted with a halogen atom. The specific example of the halogen atom is as already described. Among these, R ^a30 is preferably an alkyl group having 1 to 4 carbon atoms, more preferably a methyl group and an ethyl group, and further preferably a methyl group.
Specific examples of the alkoxy group of R ^a31 include those already exemplified in the range of 1 to 6 carbon atoms. Among these, R ^a31 is preferably an alkoxy group having 1 to 4 carbon atoms, more preferably a methoxy group and an ethoxy group, and further preferably a methoxy group.
ma is preferably 0, 1 or 2, more preferably 0 or 1, and still more preferably 0.
ma is preferably 0, 1 or 2, more preferably 0 or 1, and still more preferably 0.

Among the acid stable structural units (a2-0), the following formulas (a2-0-1), (a2-0-2), (a2-0-3) and (a2-0-4) Those represented by either are preferred.
A monomer capable of deriving such a structural unit is described in, for example, Japanese Patent Application Laid-Open No. 2010-204634.

  Acid-stable monomer capable of deriving acid-stable structural unit (a2-0) such as p-hydroxystyrene and p-hydroxy-α-methylstyrene [hereinafter referred to as “acid-stable monomer (a2)” in some cases. ] In the production of the resin (A), the acid stable structural unit (a2-0) represented by the formula (a2-0-1) or the formula (a2-0-2) is converted into the resin (A). After the phenolic hydroxy group in the acid stable monomer (a2) is protected with a protecting group such as an acetyl group to form a protected acid stable monomer (a2), the protected acid Resin (A) can also be manufactured using a stable monomer (a2). A resin (A) having an acid-stable structural unit (a2-0) can be produced by deprotecting a resin having a structural unit derived from the protected acid-stable monomer (a2) and removing the protecting group. . However, when carrying out the deprotection treatment, it is necessary to carry out the deprotection treatment without significantly damaging the other structural unit (a1).

  When the resin (A) has a structural unit derived from the monomer represented by the formula (a2-0), the content is usually 5 to 90 mol in the total structural unit (100 mol%) of the resin (A). %, Preferably 10 to 85 mol%, more preferably 15 to 80 mol%.

<Acid stable structural unit (a3)>
The lactone ring included in the acid stable structural unit (a3) may be monocyclic such as β-propiolactone ring, γ-butyrolactone ring and δ-valerolactone ring, and the monocyclic lactone ring and other rings Or a condensed ring. Among these lactone rings, a γ-butyrolactone ring and a condensed ring of a γ-butyrolactone ring and another ring are preferable.

［式（ａ３−１）中、
Ｌ^a4は、酸素原子又は＊−Ｏ−（ＣＨ₂）_k3−ＣＯ−Ｏ−（ｋ３は１〜７の整数を表す。）を表す。＊はカルボニル基との結合手を表す。
Ｒ^a18は、水素原子又はメチル基を表す。
ｐ１は０〜５の整数を表す。
Ｒ^a21は炭素数１〜４の脂肪族炭化水素基を表し、ｐ１が２以上の場合、複数のＲ^a21は同一でも異なっていてもよい。
式（ａ３−２）中、
Ｌ^a5は、酸素原子又は＊−Ｏ−（ＣＨ₂）_k3−ＣＯ−Ｏ−（ｋ３は１〜７の整数を表す。）を表す。＊はカルボニル基との結合手を表す。
ｑ１は、０〜３の整数を表す。
Ｒ^a22は、カルボキシ基、シアノ基又は炭素数１〜４の脂肪族炭化水素基を表し、ｑ１が２以上の場合、複数のＲ^a22は同一でも異なっていてもよい。
式（ａ３−３）中、
Ｌ^a6は、酸素原子又は＊−Ｏ−（ＣＨ₂）_k3−ＣＯ−Ｏ−（ｋ３は１〜７の整数を表す。）を表す。＊はカルボニル基との結合手を表す。
Ｒ^a20は、水素原子又はメチル基を表す。
ｒ１は、０〜３の整数を表す。
Ｒ^a23は、カルボキシ基、シアノ基又は炭素数１〜４の脂肪族炭化水素基を表し、ｒ１が２以上の場合、複数のＲ^a23は同一でも異なっていてもよい。］ The acid stable structural unit (a3) is preferably one represented by the following formula (a3-1), formula (a3-2) or formula (a3-3). Resin (A) may have only 1 type among these, and may have 2 or more types. In the following description, what is represented by formula (a3-1) may be referred to as “acid-stable structural unit (a3-1)”, and what is represented by formula (a3-2) is “acid In some cases, it is referred to as “stable structural unit (a3-2)”, and what is represented by the formula (a3-3) may be referred to as “acid stable structural unit (a3-3)”.

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

In formula (a3-1) to formula (a3-3), L ^{a4 to} L ^a6 are the same as those described for L ^a3 in formula (a2-1).
L ^{a4 to} L ^a6 are each independently an oxygen atom or a group represented by * —O— (CH ₂ ) _k3 —CO—O— in which k3 is an integer of 1 to 4, preferably an oxygen atom and * —O—CH ₂ —CO—O— is more preferable, and an oxygen atom is more preferable.
R ^{a18 to} R ^a21 are preferably methyl groups.
R ^a22 and R ^a23 are each independently preferably a carboxy group, a cyano group or a methyl group.
p1, q1 and r1 are preferably integers of 0 to 2, more preferably 0 or 1. When p1 is 2, two R ^a21 may be the same as or different from each other. When q1 is 2, two R ^a22 may be the same as or different from each other, and r1 is 2. Two R ^a23 may be the same or different from each other.

  Hereinafter, preferred examples of the acid stable structural unit (a3-1), the acid stable structural unit (a3-2), and the acid stable structural unit (a3-3) will be shown.

Preferable examples of the acid stable structural unit (a3-1) include the following formula (a3-1-1), formula (a3-1-2), formula (a3-1-3) and formula (a3-1-4). ).

Preferable examples of the acid stable structural unit (a3-2) include the following formula (a3-2-1), formula (a3-2-2), formula (a3-2-3) and formula (a3-2-4). ).

Preferred examples of the acid stable structural unit (a3-3) include the following formula (a3-3-1), formula (a3-3-2), formula (a3-3-3) and formula (a3-3-4). ).

The acid stable structural unit (a3-1), the acid stable structural unit (a3-2), and the acid stable structural unit (a3-3) can be derived from the monomers described in JP2010-204646A.
. Among the specific examples of the acid stable structural unit (a3), the formula (a3-1-1), the formula (a3-1-2), the formula (a3-2-3), and the formula (a3-2-4) The acid stable structural unit represented by any of these is more preferable, and the acid stable structural unit represented by Formula (a3-1-1) or Formula (a3-2-3) is more preferable.

When the resin (A) has an acid stable structural unit (a3), the total content is preferably in the range of 5 to 70 mol% with respect to all the structural units (100 mol%) of the resin (A). The range of 10 to 65 mol% is more preferable, and the range of 10 to 60 mol% is more preferable.
The content of each of the structural unit derived from the monomer (a3-1), the structural unit derived from the monomer (a3-2), and the structural unit derived from the monomer (a3-3) is the total structure of the resin (A). 5-60 mol% is preferable with respect to a unit (100 mol%), the range of 5-50 mol% is more preferable, and the range of 10-50 mol% is more preferable.

<Other acid stable structural units>
The preferred acid stable structural unit (a2) and acid stable structural unit (a3) have been described as the acid stable structural unit possessed by the resin (A). However, the resin (A) contains the acid stable structural unit (a2) and the acid stable structural unit. It may have an acid stable structural unit other than the structural unit (a3). Here, the acid stable structural unit (a4) other than the acid stable structural unit (a2) and the acid stable structural unit (a3) is referred to. Hereinafter, the acid-stable structural unit (a4) will be described by showing an acid-stable monomer (hereinafter sometimes referred to as “acid-stable monomer (a4)”) from which the acid-stable structural unit (a4) can be derived.

［式（ａ４−１）中、
Ｒ^４１は、水素原子又はメチル基を表す。
Ａ^４１は、式（ａ４−ｇ１）で表される基を表す。

（式（ａ４−ｇ１）中、
ｓｓは０〜２の整数を表す。
Ａ^４０及びＡ^４１は、それぞれ独立に、炭素数１〜５の脂肪族炭化水素基を表す。
ｓｓが２のとき、複数存在するＡ^４０は、互いに同一であるか相異なる。
Ｘ^４０は、酸素原子、カルボニル基、カルボニルオキシ基又はオキシカルボニル基を表す。
ｓｓが２のとき、複数存在するＸ^４０は、互いに同一であるか相異なる。）
Ｒ^4２は、フッ素原子を有する炭素数１〜１８の脂肪族炭化水素基を表し、該脂肪族炭化水素基を構成するメチレン基は、酸素原子又はカルボニル基で置き換わっていてもよい。］
Ａ^４１の脂肪族炭化水素基としては、直鎖状であっても、分岐していてもよい。例えば、メチレン基、エチレン基、プロパンジイル基、プロパンジイル基、ブタンジイル基、ペンタンジイル基及びペンタンジイル基等のアルカンジイル基が挙げられる。
Ａ^４１としては、炭素数１〜６のアルカンジイル基が好ましく、炭素数１〜４のアルカンジイル基がより好ましく、エチレン基がさらに好ましい。 A specific example of the acid stable monomer (a4) is, for example, a monomer represented by the following formula (a4-1) (hereinafter sometimes referred to as “monomer (a4-1)”). As will be described later, this monomer (a4-1) preferably has a fluorine atom.

[In the formula (a4-1),
R ⁴¹ represents a hydrogen atom or a methyl group.
A ⁴¹ represents a group represented by the formula (a4-g1).

(In the formula (a4-g1),
ss represents an integer of 0-2.
A ⁴⁰ and A ⁴¹ each independently represent an aliphatic hydrocarbon group having 1 to 5 carbon atoms.
When ss is 2, a plurality of A ⁴⁰ are the same or different from each other.
X ⁴⁰ represents an oxygen atom, a carbonyl group, a carbonyloxy group or an oxycarbonyl group.
When ss is 2, a plurality of X ⁴⁰ are the same or different from each other. )
R ⁴² represents a C 1-18 aliphatic hydrocarbon group having a fluorine atom, and the methylene group constituting the aliphatic hydrocarbon group may be replaced with an oxygen atom or a carbonyl group. ]
The aliphatic hydrocarbon group for A ⁴¹ may be linear or branched. Examples thereof include alkanediyl groups such as a methylene group, ethylene group, propanediyl group, propanediyl group, butanediyl group, pentanediyl group, and pentanediyl group.
The A ^41, preferably alkanediyl group having 1 to 6 carbon atoms, more preferably an alkanediyl group having 1 to 4 carbon atoms, an ethylene group is more preferred.

等が挙げられる。 Specific examples of the group represented by the formula (a4-g1) (hereinafter may be referred to as “group (a4-g1)”) are shown below. In each specific example, * represents a bond.
As the group having an oxygen atom (a4-g1),

Etc.

等が挙げられる。 As the group having a carbonyl group (a4-g1),

Etc.

等が挙げられる。 As the group having a carbonyloxy group (a4-g1),

Etc.

等が挙げられる。 As the group having an oxycarbonyl group (a4-g1),

Etc.

R ⁴² is a group in which at least one of the hydrogen atoms contained in the aliphatic hydrocarbon group is replaced with a fluorine atom. The aliphatic hydrocarbon group may partially have a carbon-carbon unsaturated bond, but is a saturated aliphatic hydrocarbon group having no carbon-carbon unsaturated bond (aliphatic saturated hydrocarbon group). Is preferred. Examples of the aliphatic saturated hydrocarbon group include alkyl groups (straight and branched) and alicyclic hydrocarbon groups, and aliphatic hydrocarbon groups obtained by combining alkyl groups and alicyclic hydrocarbon groups.
Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, and an octyl group.
The alicyclic hydrocarbon group may be monocyclic or polycyclic. Examples of the monocyclic alicyclic hydrocarbon group include cycloalkyl groups such as a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. Examples of the polycyclic alicyclic hydrocarbon group include decahydronaphthyl group, adamantyl group, norbornyl group, and groups shown below.

  Examples of the group in which at least one hydrogen atom contained in the aliphatic hydrocarbon group is replaced with a fluorine atom include a difluoromethyl group, a trifluoromethyl group, a 1,1-difluoroethyl group, a 2,2-difluoroethyl group, 2,2,2-trifluoroethyl group, perfluoroethyl group, 1,1,2,2-tetrafluoropropyl group, 1,1,2,2,3,3-hexafluoropropyl group, perfluoroethylmethyl group, 1- (trifluoromethyl) -1,2,2,2-tetrafluoroethyl group, perfluoropropyl group, 1,1,2,2-tetrafluorobutyl group, 1,1,2,2,3,3- Hexafluorobutyl group, 1,1,2,2,3,3,4,4-octafluorobutyl group, perfluorobutyl group, 1,1-bis (trifluoro) methyl- , 2,2-trifluoroethyl group, 2- (perfluoropropyl) ethyl group, 1,1,2,2,3,3,4,4-octafluoropentyl group, perfluoropentyl group, 1,1,2, 2,3,3,4,4,5,5-decafluoropentyl group, 1,1-bis (trifluoromethyl) -2,2,3,3,3-pentafluoropropyl group, perfluoropentyl group, perfluoro Cyclopentyl group, 2- (perfluorobutyl) ethyl group, 1,1,2,2,3,3,4,4,5,5-decafluorohexyl group, 1,1,2,2,3,3,4 , 4, 5, 5, 6, 6-dodecafluorohexyl group, perfluorocyclohexyl group, perfluoropentylmethyl group, perfluorohexyl group and the like.

（式（ａ−ｇ２）中、
Ａ¹³は、フッ素原子を有していてもよい炭素数１〜１５の２価の脂肪族炭化水素基を表す。
Ｘ¹²は、酸素原子、カルボニル基、カルボニルオキシ基又はオキシカルボニル基を表す。
Ａ¹⁴は、フッ素原子を有していてもよい炭素数１〜１５の１価の脂肪族炭化水素基を表す。
但し、Ａ¹³又はＡ¹⁴の少なくとも一方はフッ素原子を有し、それらの炭素数の合計は１７以下である。） Examples of the group in which the methylene group constituting the aliphatic hydrocarbon group is replaced with an oxygen atom or a carbonyl group include a group represented by the formula (a-g2).

(In the formula (a-g2),
A ¹³ represents a C 1-15 divalent aliphatic hydrocarbon group which may have a fluorine atom.
X ¹² represents an oxygen atom, a carbonyl group, a carbonyloxy group or an oxycarbonyl group.
A ¹⁴ represents a monovalent aliphatic hydrocarbon group having 1 to 15 carbon atoms which may have a fluorine atom.
However, at least one of A ¹³ or A ¹⁴ has a fluorine atom, and the total number of carbon atoms thereof is 17 or less. )

The divalent aliphatic hydrocarbon group having a fluorine atom of A ¹³ is an alkanediyl group having a fluorine atom and a divalent alicyclic hydrocarbon group having a fluorine atom (preferably a cycloalkanediyl having a fluorine atom). Group). The alkanediyl group having a fluorine atom is one in which part or all of the hydrogen atoms contained in the alkanediyl group are substituted with a fluorine atom, and the divalent alicyclic hydrocarbon group having a fluorine atom is 2 Some or all of the hydrogen atoms contained in the valent alicyclic hydrocarbon group are substituted with fluorine atoms.

An aliphatic hydrocarbon group R ⁴² is a fluorine ^atom, and ^{A 41} is an ethylene group (a4-1), the following formula (a4-1-1) ~ formula (a4-1-22) The compound represented by either is mentioned.

The aliphatic hydrocarbon group having a fluorine atom of R ⁴² is a perfluoroalkyl group in which all of the hydrogen atoms contained in the alkyl group are substituted with fluorine atoms (for example, trifluoromethyl group, perfluoroethyl group, perfluoropropyl group, perfluoro group). A butyl group, a perfluoropentyl group, a perfluorohexyl group, a perfluoroheptyl group, a perfluorooctyl group, etc.) or a perfluorocycloalkyl group in which all of the hydrogen atoms contained in the cycloalkyl group are substituted with fluorine atoms is preferred.

The compound in which R ⁴² is a perfluoroalkyl group or a perfluorocycloalkyl group includes the above-described formula (a4-1-3), formula (a4-1-4), formula (a4-1-7), and formula (a4- 1-8), formula (a4-1-11), formula (a4-1-12), formula (a4-1-15), formula (a4-1-16), formula (a4-1-19), A compound represented by any one of formula (a4-1-20), formula (a4-1-21) and formula (a4-1-22) is applicable.

R ⁴² is more preferably a perfluoroalkyl group. More preferably, it is a C1-C6 perfluoroalkyl group, More preferably, it is a C1-C3 perfluoroalkyl group.

［式（ａ４−１’）中、Ａ^１３、Ａ^１４、Ａ^４１、Ｒ^４１及びＸ^１２は、それぞれ前記と同義である。］ The compound (a) in which R ⁴² is the formula (a-g2) is one represented by the following formula (a4-1 ′) (hereinafter sometimes referred to as “compound (a4-1 ′)”). .

[In the formula (a4-1 ′), A ¹³ , A ¹⁴ , A ⁴¹ , R ⁴¹ and X ¹² are as defined above. ]

In the compound (a4-1 ′), both A ¹³ and A ¹⁴ may have a fluorine atom, but A ¹³ is an aliphatic hydrocarbon group having a fluorine atom, or A ¹⁴ has a fluorine atom. What is an aliphatic hydrocarbon group is preferable. Further, it is preferable that A ¹³ is an aliphatic hydrocarbon group having a fluorine atom, among them, A ¹³ is more preferable alkanediyl group having a fluorine atom, and particularly preferred is a perfluoro alkanediyl group . The “perfluoroalkanediyl group” refers to an alkanediyl group in which all hydrogen atoms are substituted with fluorine atoms.

As the compound (a4-1 ′) in which R ⁴² is a perfluoroalkanediyl group and A ⁴¹ is an ethylene group, any of the following formulas (a4-1′-1) to (a4-1′-46) The compound represented by these is mentioned.

The number of carbon atoms of A ¹³ and A ¹⁴ is their sum is arbitrarily selected in the range of 17 or less, the number of carbon atoms of A ¹³ are members preferably 1-6, 1-3 is more preferable.
The number of carbon atoms of A ¹⁴ is preferably 4 to 15, 5 to 12 is more preferable. Further preferred A ¹⁴ is an alicyclic hydrocarbon group having 6 to 12 carbon atoms, and a cyclohexyl group and an adamantyl group are even more preferred.

Preferred examples of * -A ¹³ -X ¹² -A ¹⁴ (* is a bond with a carbonyl group) include the following groups.

このような基を有する化合物（ａ４−１’）は、上述した式（ａ４−１’−７）〜式（ａ４−１’−４２）のいずれかで表される化合物が該当する。

The compound (a4-1 ′) having such a group corresponds to the compound represented by any one of the above-described formula (a4-1′-7) to formula (a4-1′-42).

  When the resin (A) includes a structural unit derived from the compound (a4-1), the content is usually 1 to 20 mol% with respect to all the structural units of the resin (A), and 2 to 15 Mol% is preferable, and 3 to 10 mol% is more preferable.

  As described above, the structural unit (a1-1) or the structural unit (a1-2) suitable as the structural unit (a1) of the resin (A), the other structural unit (a1), and the acid stable structural unit are preferable. Although the acid stable structural unit (a2), the acid stable structural unit (a3), and the acid stable structural unit (a4) have been described in detail, they may have other structural units. Mention may be made of structural units well known in the art.

Moreover, resin which has a structural unit derived from the monomer (a4-1) shown here can also be contained in this resist composition separately from resin (A). In other words, the resin (A) having an acid labile group [structural unit (a1)] in the molecule and the structural unit derived from the monomer (a4-1) having no acid labile group in the molecule. A resin (hereinafter, sometimes referred to as “resin (X)”) may be combined and contained in the resist composition.
In this case, the content ratio of the structural unit derived from the monomer (a4-1) in the resin (X) is preferably 80 mol% or more with respect to all the structural units (100 mol%) of the resin (X). 85 mol% or more is more preferable, and 90 mol% or more is further more preferable.

  In the resist composition, a resin (A) having acid action characteristics and a resin (X) not having acid action characteristics may be used in combination. In this case, as the resin (X), a monomer ( A resin having a structural unit derived from a4-1) can be used. More specifically, the resin (X) preferably has a structural unit derived from the monomer (a4-1 ′) among the structural units derived from the monomer (a4-1). The content ratio of the structural unit derived from the monomer (a4-1) [monomer (a4-1 ′)] with respect to the total structural unit of the resin (X) is, for example, preferably 80 mol% or more, and more preferably 85 mol% or more. 90 mol% or more is more preferable. Resin (X) may consist essentially of a structural unit derived from monomer (a4-1) [monomer (a4-1 ′)]. In addition, as the structural unit that the resin (X) may have other than the structural unit derived from the monomer (a4-1), the above-mentioned acid stable structural unit (a2), acid stable structural unit (a3), and the like Can be mentioned.

Resin (X) is also preferable if it has a structural unit derived from monomer (a4-1) [monomer (a4-1 ′)], but if it consists of a structural unit that does not have an acid labile group, You may further have a structural unit well-known in this technical field.

<Method for producing resin (A)>
The resin (A) is obtained by copolymerizing the monomer (a1) for deriving the structural unit (a1), more preferably the monomer (a1) and an acid stable monomer for deriving the acid stable structural unit. More preferably, the monomer (a1) for deriving the structural unit (a1-1) and / or the structural unit (a1-2), and the acid-stable structural unit (a2) and / or the acid-stable structural unit (a3) are derived. Copolymerized with an acid stable monomer. For example, when the resist composition is used for EUV exposure, the monomer (a1) that induces the structural unit (a1-1) and / or the structural unit (a1-2), and the acid stable structural unit (a2- And an acid-stable monomer derived from 0).
The resin (A) further preferably has a structural unit (a1-1) having an adamantyl group as the structural unit (a1). The resin (A) can be produced by subjecting the monomer as described above to a known polymerization method (for example, radical polymerization method) and polymerizing (copolymerizing) it.
On the other hand, the resin (X) is preferably obtained by polymerizing the monomer (a4-1) [monomer (a4-1 ′)] by a known polymerization method, and this polymerization [production of resin (X)] In addition to monomer (a4-1) [monomer (a4-1 ′)], other acid-stable monomers [for example, monomers that induce acid-stable structural units (a2) or acid-stable structural units (a3)] These may be copolymerized using these.

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). In addition, the weight average molecular weight here is calculated | required as a conversion value of a standard polystyrene reference | standard by gel permeation chromatography analysis. Detailed analysis conditions for this analysis are described in the Examples of the present application.
On the other hand, when the resin (X) is used in the resist composition, the weight average molecular weight of the resin (X) is preferably 8,000 or more (more preferably 10,000 or more), 80,000 or less (more preferably). Is less than 60,000). The means for measuring the weight average molecular weight of the resin (X) is the same as that for the resin (A).

<Basic compound (C)>
The resist composition of the present invention preferably further contains a basic compound (C). The basic compound (C) acts as a quencher.

  The basic compound (C) is preferably a basic nitrogen-containing organic compound, and examples thereof include amines and ammonium salts. Examples of amines include aliphatic amines and aromatic amines. Aliphatic amines include primary amines, secondary amines and tertiary amines. The basic compound (C) is preferably a compound represented by the formula (C1) to a compound represented by the formula (C8), more preferably a compound represented by the formula (C1-1). It is done.

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

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

［式（Ｃ１−１）中、Ｒ^c2及びＲ^c3は、上記と同じ意味を表す。
Ｒ^c4は、炭素数１〜６のアルキル基、炭素数１〜６のアルコキシ基、炭素数５〜１０の脂環式炭化水素又は炭素数６〜１０の芳香族炭化水素基を表す。
ｍ３は０〜３の整数を表し、ｍ３が２以上のとき、複数のＲ^c4は、互いに同一であるか相異なる。］

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

［式（Ｃ２）、式（Ｃ３）及び式（Ｃ４）中、Ｒ^c5、Ｒ^c6、Ｒ^c7及びＲ^c8は、それぞれ独立に、Ｒ^c1と同じ意味を表す。
Ｒ^c9は、炭素数１〜６のアルキル基、炭素数３〜６の脂環式炭化水素基又は炭素数２〜６のアルカノイル基を表す。
ｎ３は０〜８の整数を表し、ｎ３が２以上のとき、複数のＲ^c9の全部又は一部は同じであってもよい。］

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

［式（Ｃ５）及び式（Ｃ６）中、Ｒ^c10、Ｒ^c11、Ｒ^c12、Ｒ^c13及びＲ^c16は、それぞれ独立に、Ｒ^c1と同じ意味を表す。
Ｒ^c14、Ｒ^c15及びＲ^c17は、それぞれ独立に、Ｒ^c4と同じ意味を表す。
ｏ３及びｐ３は、それぞれ独立に０〜３の整数を表し、ｏ３が２以上であるとき、複数のＲ^c14の全部又は一部は同じであってもよい。ｐ３が２以上であるとき、複数のＲ^c15の全部又は一部は同じであってもよい。
Ｌ^c1は、炭素数１〜６のアルカンジイル基、−ＣＯ−、−Ｃ（＝ＮＨ）−、−Ｓ−又はこれらを組合せた２価の基を表す。］

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

［式（Ｃ７）及び式（Ｃ８）中、Ｒ^c18、Ｒ^c19及びＲ^c20は、それぞれ独立に、Ｒ^c4と同じ意味を表す。
ｑ３、ｒ３及びｓ３は、それぞれ独立に０〜３の整数を表し、ｑ３が２以上であるとき、複数のＲ^c18の全部又は一部は同じであってもよい。ｒ３が２以上であるとき、複数のＲ^c19の全部又は一部は同じであってもよい。ｓ３が２以上であるとき、複数のＲ^c20の全部又は一部は同じであってもよい。
Ｌ^c2は、単結合又は炭素数１〜６のアルカンジイル基、−ＣＯ−、−Ｃ（＝ＮＨ）−、−Ｓ−又はこれらを組合せた２価の基を表す。］

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

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

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

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

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

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

<Solvent (D)>
This resist composition preferably further contains a solvent (D). The solvent (D) contained in the resist composition is coated on the substrate in the production of a resist pattern, which will be described later, according to the type and amount of the salt (I) or resin (A). From the standpoint of good coating properties during the process, an optimal one can be selected as appropriate.

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

<Other ingredients>
The resist composition comprises an acid generator and a resin (A) containing salt (I) as an active ingredient, and a solvent (D), an acid generator (B) and a basic compound (C) used as necessary. You may contain the structural component. This component may be referred to as “component (F)”. The component (F) is not particularly limited, and examples thereof include additives known in the resist field, such as polymer compounds other than the resin (A), sensitizers, dissolution inhibitors, surfactants, stabilizers and dyes. It is done.

<Preparation method of the present resist composition>
The present resist composition can be usually prepared by mixing the salt (I) and the resin (A) in the presence of the solvent (D). Furthermore, you may mix an acid generator (B), a basic compound (C), and / or a component (F) as needed as above-mentioned. It is preferable to mix the basic compound (C). The mixing order is arbitrary and is not particularly limited. The temperature at the time of mixing can select the suitable temperature range from the range of 10-40 degreeC according to the solubility with respect to solvent (D), such as a kind (resin (A)), such as resin (A). An appropriate mixing time can be selected from 0.5 to 24 hours depending on the mixing temperature. The mixing means is not particularly limited, and stirring and mixing can be used.
By selecting the amount of each component used when preparing the resist composition of the present invention, the content of each component in the resist composition of the present invention can be adjusted.

  The content ratio of the acid generator in the resist composition is preferably 40% by mass or less, more preferably 35% by mass or less, and preferably 1% by mass or more, more preferably based on the solid content of the resist composition. Is 3% by mass or more.

  The content of the salt (I) is preferably 10 parts by mass or more, more preferably 30 parts by mass or more with respect to 100 parts by mass of the total amount of the acid generator. In the present resist composition, substantially only the salt (I) can be used as an acid generator. As the acid generator other than the salt (I), the acid generator (B) is preferable.

  A preferable range of the content ratio of the resin (A) in the resist composition is determined based on the solid content of the resist composition. Specifically, the resin (A) is preferably 80% by mass or more and 99% by mass or less based on the mass of the solid content. When the resin composition (X) is contained in the resist composition, the content ratio is about 0.1 to 30% by mass, more preferably 0.5 to 20% by mass, based on the content of the resin (A). About 1 to 15% by mass.

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

  The content ratio of the solvent (D) in the present resist composition is 90% by mass or more, preferably 92% by mass or more, more preferably 94% by mass or more, based on the total mass of the present resist composition. 0.9 mass% or less, preferably 99 mass% or less.

  When the resist composition contains the component (F), the appropriate content can be adjusted according to the type of the component (F).

  As described above, each of the acid generator and the resin (A) containing the salt (I) as an active ingredient, and the solvent (D), the basic compound (C) or the ingredient (F) used as necessary is preferably contained. After mixing in an amount, it is preferable to filter using a filter having a pore size of about 0.003 to 0.2 μm.

<Method for producing resist pattern>
Specifically showing a method for producing a resist pattern using the present resist composition,
(1) a step of applying the resist composition on a substrate;
(2) The process of drying the composition after application | coating and forming a composition layer,
(3) a step of exposing the composition layer,
(4) a step of heating the composition layer after exposure, and (5) a step of developing the composition layer after heating. Hereinafter, each of the steps shown here is referred to as “step (1)” to “step (5)”.

  Application of the resist composition of the present invention on the substrate in the step (1) can be performed by a coating apparatus widely used for applying a resist material for fine processing of a semiconductor such as a spin coater. The film thickness of the coating film can be adjusted by variously adjusting the conditions of the coating apparatus (coating conditions), and by performing appropriate preliminary experiments, the coating conditions can be adjusted so that the coating film has a desired film thickness. You can choose. As the substrate before applying the resist composition of the present invention, various substrates to be subjected to fine processing can be selected. The substrate may be washed or an antireflection film may be formed before applying the resist composition of the present invention. For example, a commercially available composition for an organic antireflection film can be used for forming the antireflection film.

In the drying in the step (2), the resist composition of the present invention applied on the substrate, that is, the coating film is dried. Such drying is performed by evaporating the solvent from the coating film by, for example, heating means using a heating device such as a hot plate (so-called pre-baking), decompressing means using a decompressing device, or a combination of these means. It is done by removing. The drying conditions can be selected according to the type of the solvent (E) contained in the resist composition of the present invention. For example, in the case of a heating means using a hot plate, the surface temperature of the hot plate is in the range of about 50 to 200 ° C. It is preferable to do. In the case of the decompression unit, after the substrate on which the coating film is formed is sealed in the decompression device, the internal pressure of the decompression device may be set to about 1 to 1.0 × 10 ⁵ Pa. Thus, by drying the coating film, a composition layer is formed on the substrate.

Step (3) is a step of exposing the composition layer, and preferably a step of exposing the composition layer using an exposure machine. The exposure is performed through a mask (photomask) on which a desired pattern to be finely processed is formed. As an exposure light source of the exposure apparatus, a laser beam emitting in the ultraviolet region such as a KrF excimer laser (wavelength 248 nm), an ArF excimer laser (wavelength 193 nm), an F ₂ excimer laser (wavelength 157 nm), or a solid-state laser light source (YAG In addition, various lasers such as a laser beam from a laser beam from a semiconductor laser or the like to emit a harmonic laser beam in the far ultraviolet region or the vacuum ultraviolet region can be used. The exposure machine may be an immersion exposure machine. The exposure machine may irradiate an electron beam or extreme ultraviolet light (EUV). In this specification, irradiating these radiations may be collectively referred to as “exposure”.
By exposing through a mask, the composition layer has an exposed portion (exposed portion) and an unexposed portion (unexposed portion). In the composition layer of the exposed portion, the salt (I) and the acid generator (B) contained in the composition layer generate an acid upon receiving exposure energy, and further, by the action with the generated acid, “insoluble in an alkaline aqueous solution”. Alternatively, the acid labile group of the resin (A), which is a resin that is hardly soluble and becomes soluble in an alkaline aqueous solution by the action of an acid, generates a hydrophilic group by a deprotection reaction. A certain resin (A) becomes soluble in an alkaline aqueous solution. On the other hand, since the exposure energy is not received in the unexposed area, the resin (A) remains insoluble or hardly soluble in the alkaline aqueous solution. Since the composition layer in the exposed portion and the composition layer in the unexposed portion are significantly different in solubility in an alkaline aqueous solution, a resist pattern can be formed by development with the alkaline aqueous solution.

  Step (4) is a step of heating the composition layer after exposure (so-called post-exposure baking). The heating promotes a deprotecting group reaction that may occur in the exposed area. Such heat treatment is preferably the heating means using the hot plate shown in the step (2). In addition, when performing the heating means using a hot plate in a process (4), about 50-200 degreeC is preferable for the surface temperature of this hot plate, and about 70-150 degreeC is more preferable.

Step (5) is a step of developing the heated composition layer, and preferably the heated composition layer is developed with a developing device. In the step of developing, when the composition layer after heating is brought into contact with an alkaline aqueous solution, the exposed composition layer is dissolved and removed in the alkaline aqueous solution, and the unexposed composition layer remains on the substrate. A resist pattern is manufactured on the substrate.
As the alkaline aqueous solution, those known in this technical field called “alkaline developer” can be used. Examples of the alkaline aqueous solution include an aqueous solution of tetramethylammonium hydroxide and an aqueous solution of (2-hydroxyethyl) trimethylammonium hydroxide (commonly called choline).

  After development, it is preferable to perform a rinsing treatment with ultrapure water or the like. Furthermore, it is preferable to remove moisture remaining on the substrate and the resist pattern.

<Application>
The resist composition of the present invention includes a resist composition for KrF excimer laser exposure, a resist composition for ArF excimer laser exposure, a resist composition for electron beam (EB) irradiation or a resist composition for EUV exposure, and a liquid It is suitable as a resist composition for immersion exposure.

Hereinafter, the present invention will be described in detail by way of examples.
In Examples and Comparative Examples, “%” and “part” representing the content and the amount used 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)

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

式（Ｉ−１−ａ）で表される化合物６．４３部及びクロロホルム３８．６０部を、反応器に仕込み、２３℃で３０分間攪拌した。次いで、式（Ｉ−１−ｂ）で表される化合物５．９１部を添加した。６０℃程度まで昇温し、同温度で２時間攪拌することにより、式（Ｉ−１−ｃ）で表される化合物を含む溶液を得た。得られた式（Ｉ−１−ｃ）で表される化合物を含む溶液に、式（Ｉ−１−ｄ）で表される化合物５．００部及びクロロホルム１５．００部の混合溶液を仕込み、２３℃で２４時間攪拌した。得られた反応物に、イオン交換水２６．８０部を加え、２３℃で３０分間攪拌した。その後、静置し、分液して有機層を得た。このような水洗操作を６回繰り返した。水洗後の有機層を濃縮して得られた濃縮物に、ｎ−ヘプタン６６．１５部を仕込み、２３℃で１時間攪拌した後、ろ過することにより、式（Ｉ−１−ｅ）で表される化合物７．６６部を得た。 Example 1: Synthesis of a salt represented by the formula (I-1)

6.43 parts of the compound represented by the formula (I-1-a) and 38.60 parts of chloroform were charged into a reactor and stirred at 23 ° C. for 30 minutes. Then, 5.91 parts of a compound represented by the formula (I-1-b) was added. The solution was heated to about 60 ° C. and stirred at the same temperature for 2 hours to obtain a solution containing the compound represented by the formula (I-1-c). A solution containing the compound represented by the formula (I-1-c) thus obtained was charged with a mixed solution of 5.00 parts of the compound represented by the formula (I-1-d) and 15.00 parts of chloroform, The mixture was stirred at 23 ° C. for 24 hours. To the obtained reaction product, 26.80 parts of ion-exchanged water was added and stirred at 23 ° C. for 30 minutes. Then, it left still and liquid-separated and obtained the organic layer. Such washing operation was repeated 6 times. The concentrate obtained by concentrating the organic layer after washing with water was charged with 66.15 parts of n-heptane, stirred at 23 ° C. for 1 hour, and then filtered to obtain the formula (I-1-e). 7.66 parts of the compound obtained are obtained.

式（Ｉ−１−ｅ）で表される化合物７．００部及びテトラヒドロフラン３５．００部を、反応器に仕込み、２３℃で３０分間攪拌した。０℃まで冷却し、水素化ホウ素ナトリウム０．３９部及びイオン交換水５．８０部の水溶液を２５分かけて滴下した。更に、０℃で１時間攪拌した後、イオン交換水４８．１９部及び酢酸エチル１４４．５７部を仕込み、２３℃で３０分間攪拌した。その後、静置し、分液して有機層を得た。得られた有機層に、イオン交換水４８．１９部を仕込み、２３℃で３０分間攪拌した。その後、静置し、分液して有機層を得た。このような水洗操作を５回繰り返した。水洗後の有機層を濃縮して得られた濃縮物に、ｎ−ヘプタン３２．７５部を加えて攪拌した。得られた上澄液を除去し、濃縮した。得られた濃縮物を酢酸エチルに溶解した後、濃縮することにより、式（Ｉ−１−ｆ）で表される化合物４．７４部を得た。

7.00 parts of the compound represented by the formula (I-1-e) and 35.00 parts of tetrahydrofuran were charged into a reactor and stirred at 23 ° C. for 30 minutes. The solution was cooled to 0 ° C., and an aqueous solution of sodium borohydride (0.39 parts) and ion-exchanged water (5.80 parts) was added dropwise over 25 minutes. Furthermore, after stirring at 0 ° C. for 1 hour, 48.19 parts of ion-exchanged water and 144.57 parts of ethyl acetate were added and stirred at 23 ° C. for 30 minutes. Then, it left still and liquid-separated and obtained the organic layer. To the obtained organic layer, 48.19 parts of ion-exchanged water was added and stirred at 23 ° C. for 30 minutes. Then, it left still and liquid-separated and obtained the organic layer. Such washing operation was repeated 5 times. To the concentrate obtained by concentrating the organic layer after washing with water, 32.75 parts of n-heptane was added and stirred. The resulting supernatant was removed and concentrated. The obtained concentrate was dissolved in ethyl acetate and then concentrated to obtain 4.74 parts of a compound represented by the formula (I-1-f).

式（Ｉ−１−ｇ）で表される塩３．４９部及びアセトニトリル１７．５０部を、反応器に仕込み、２３℃で３０分間攪拌した。その後、式（Ｉ−１−ｂ）で表される化合物１．５２部を添加し、７０℃程度まで昇温した後、同温度で２時間攪拌し、式（Ｉ−１−ｈ）で表される化合物を含む溶液を得た。得られた式（Ｉ−１−ｈ）で表される化合物を含む溶液に、５０℃で、式（Ｉ−１−ｆ）で表される化合物２．４６部及びクロロホルム７．５７部の混合溶液を１時間かけて滴下し、さらに、６０℃で１２時間攪拌した後、得られた反応物を濃縮した。得られた濃縮物に、クロロホルム６６．９２部及び２％シュウ酸水５０．１９部を加え、２３℃で３０分間攪拌した。その後、静置し、分液して有機層を得た。得られた有機層に、イオン交換水３３．４６部を加え、２３℃で３０分間攪拌した。
その後、静置し、分液して有機層を得た。この水洗操作をさらに５回繰り返した。水洗後の有機層に活性炭０．９７部を仕込み、２３℃で３０分間攪拌し、ろ過した。ろ液を濃縮し、得られた濃縮物に、ｔｅｒｔ−ブチルメチルエーテル１８．７５部を加えて攪拌した。得られた上澄液を除去し、濃縮した。得られた濃縮物をアセトニトリルに溶解した後、濃縮することにより、式（Ｉ−１）で表される塩２．９４部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ２６３．１
ＭＡＳＳ（ＥＳＩ（−）Ｓｐｅｃｔｒｕｍ）：Ｍ⁻ ５０１．１

3.49 parts of the salt represented by the formula (I-1-g) and 17.50 parts of acetonitrile were charged into a reactor and stirred at 23 ° C. for 30 minutes. Thereafter, 1.52 parts of the compound represented by the formula (I-1-b) was added, and the temperature was raised to about 70 ° C., followed by stirring at the same temperature for 2 hours, and the formula (I-1-h). A solution containing the compound to be obtained was obtained. The solution containing the compound represented by the formula (I-1-h) thus obtained was mixed with 2.46 parts of the compound represented by the formula (I-1-f) and 7.57 parts of chloroform at 50 ° C. The solution was added dropwise over 1 hour, and the mixture was further stirred at 60 ° C. for 12 hours, and then the obtained reaction product was concentrated. To the obtained concentrate, 66.92 parts of chloroform and 50.19 parts of 2% oxalic acid water were added and stirred at 23 ° C. for 30 minutes. Then, it left still and liquid-separated and obtained the organic layer. To the obtained organic layer, 33.46 parts of ion-exchanged water was added and stirred at 23 ° C. for 30 minutes.
Then, it left still and liquid-separated and obtained the organic layer. This washing operation was further repeated 5 times. The organic layer after washing was charged with 0.97 parts of activated carbon, stirred at 23 ° C. for 30 minutes, and filtered. The filtrate was concentrated, and 18.75 parts of tert-butyl methyl ether was added to the resulting concentrate and stirred. The resulting supernatant was removed and concentrated. The obtained concentrate was dissolved in acetonitrile and then concentrated to obtain 2.94 parts of the salt represented by the formula (I-1).
MASS (ESI (+) Spectrum): M ⁺ 263.1
MASS (ESI (−) Spectrum): M ^- 501.1

式（Ｉ−４−ａ）で表される化合物５．３９部及びクロロホルム３２．３６部を、反応器に仕込み、２３℃で３０分間攪拌し、式（Ｉ−４−ｂ）で表される化合物４．９５部を添加した。その後、６０℃程度まで昇温し、同温度で２時間攪拌することにより、式（Ｉ−４−ｃ）で表される化合物を含む溶液を得た。得られた式（Ｉ−４−ｃ）で表される化合物を含む溶液に、式（Ｉ−４−ｄ）で表される化合物５．００部及びクロロホルム１５．００部の混合溶液を仕込み、２３℃で４時間攪拌した。得られた反応混合物に、イオン交換水２３．６８部を加え、２３℃で３０分間攪拌した。その後、静置し、分液して有機層を得た。このような水洗操作を６回繰り返した。水洗後の有機層を濃縮することにより、式（Ｉ−４−ｅ）で表される化合物６．９８部を得た。 Example 2: Synthesis of a salt represented by the formula (I-4)

5.39 parts of a compound represented by the formula (I-4-a) and 32.36 parts of chloroform are charged into a reactor, stirred at 23 ° C. for 30 minutes, and represented by the formula (I-4-b). 4.95 parts of compound were added. Then, it heated up to about 60 degreeC and stirred at the same temperature for 2 hours, and the solution containing the compound represented by a formula (I-4-c) was obtained. A solution containing the compound represented by the formula (I-4-c) thus obtained was charged with a mixed solution of 5.00 parts of the compound represented by the formula (I-4-d) and 15.00 parts of chloroform, Stir at 23 ° C. for 4 hours. To the obtained reaction mixture, 23.68 parts of ion-exchanged water was added and stirred at 23 ° C. for 30 minutes. Then, it left still and liquid-separated and obtained the organic layer. Such washing operation was repeated 6 times. The organic layer after washing with water was concentrated to obtain 6.98 parts of a compound represented by the formula (I-4-e).

式（Ｉ−４−ｅ）で表される化合物５．７６部及びアセトニトリル２９．０５部を、反応器に仕込み、２３℃で３０分間攪拌した後、０℃まで冷却し、水素化ホウ素ナトリウム０．２９部及びイオン交換水４．３７部の水溶液を２０分かけて滴下した。更に、０℃で１時間攪拌した後、イオン交換水３９．５２部及び酢酸エチル１１８．５６部を仕込み、２３℃で３０分間攪拌した。その後、静置し、分液して有機層を得た。得られた有機層に、イオン交換水３９．５２部を仕込み、２３℃で３０分間攪拌した。その後、静置し、分液して有機層を得た。このような水洗操作を５回繰り返した。水洗後の有機層を濃縮し、得られた濃縮物に、ｎ−ヘプタン４２．８０部を加えて攪拌した。得られた上澄液を除去し、濃縮した。得られた濃縮物を酢酸エチルに溶解した後、濃縮することにより、式（Ｉ−４−ｆ）で表される化合物４．２３部を得た。

5.76 parts of the compound represented by the formula (I-4-e) and 29.05 parts of acetonitrile were charged into a reactor, stirred at 23 ° C. for 30 minutes, cooled to 0 ° C., sodium borohydride 0 An aqueous solution of .29 parts and 4.37 parts of ion exchange water was added dropwise over 20 minutes. Furthermore, after stirring at 0 ° C. for 1 hour, 39.52 parts of ion-exchanged water and 118.56 parts of ethyl acetate were added and stirred at 23 ° C. for 30 minutes. Then, it left still and liquid-separated and obtained the organic layer. To the obtained organic layer, 39.52 parts of ion-exchanged water was added and stirred at 23 ° C. for 30 minutes. Then, it left still and liquid-separated and obtained the organic layer. Such washing operation was repeated 5 times. The organic layer after washing with water was concentrated, and 42.80 parts of n-heptane was added to the resulting concentrate and stirred. The resulting supernatant was removed and concentrated. The obtained concentrate was dissolved in ethyl acetate and then concentrated to obtain 4.23 parts of a compound represented by the formula (I-4-f).

式（Ｉ−４−ｇ）で表される塩３．４９部及びアセトニトリル１７．５０部を、反応器に仕込み、２３℃で３０分間攪拌した。その後、式（Ｉ−４−ｂ）で表される化合物１．５２部を添加し、７０℃程度まで昇温した後、同温度で２時間攪拌し、式（Ｉ−４−ｈ）で表される化合物を含む溶液を得た。得られた式（Ｉ−４−ｈ）で表される化合物を含む溶液に、５０℃で、式（Ｉ−４−ｆ）で表される化合物２．６９部及びクロロホルム８．０７部の混合溶液を１時間かけて滴下し、さらに、６０℃で１２時間攪拌した後、得られた反応物を濃縮した。得られた濃縮物に、クロロホルム６５．４８部及び２％シュウ酸水５０．２０部を加え、２３℃で３０分間攪拌した。その後、静置し、分液して有機層を得た。得られた有機層に、イオン交換水３５．００部を加え、２３℃で３０分間攪拌した。
その後、静置し、分液して有機層を得た。この水洗操作をさらに５回繰り返した。水洗後の有機層に活性炭１．００部を仕込み、２３℃で３０分間攪拌し、ろ過した。ろ液を濃縮し、得られた濃縮物に、ｔｅｒｔ−ブチルメチルエーテル２０．００部を加えて攪拌した。得られた上澄液を除去し、濃縮した。得られた濃縮物をアセトニトリルに溶解した後、濃縮することにより、式（Ｉ−４）で表される塩２．８３部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ２６３．１
ＭＡＳＳ（ＥＳＩ（−）Ｓｐｅｃｔｒｕｍ）：Ｍ⁻ ５３３．１

3.49 parts of the salt represented by the formula (I-4-g) and 17.50 parts of acetonitrile were charged into a reactor and stirred at 23 ° C. for 30 minutes. Thereafter, 1.52 parts of the compound represented by the formula (I-4-b) was added, the temperature was raised to about 70 ° C., and the mixture was stirred at the same temperature for 2 hours, and represented by the formula (I-4-h). A solution containing the compound to be obtained was obtained. The solution containing the compound represented by the formula (I-4-h) thus obtained was mixed with 2.69 parts of the compound represented by the formula (I-4-f) and 8.07 parts of chloroform at 50 ° C. The solution was added dropwise over 1 hour, and the mixture was further stirred at 60 ° C. for 12 hours, and then the obtained reaction product was concentrated. To the obtained concentrate, 65.48 parts of chloroform and 50.20 parts of 2% oxalic acid water were added and stirred at 23 ° C. for 30 minutes. Then, it left still and liquid-separated and obtained the organic layer. To the obtained organic layer, 35.00 parts of ion-exchanged water was added and stirred at 23 ° C. for 30 minutes.
Then, it left still and liquid-separated and obtained the organic layer. This washing operation was further repeated 5 times. The organic layer after washing with water was charged with 1.00 parts of activated carbon, stirred at 23 ° C. for 30 minutes, and filtered. The filtrate was concentrated, and 20.00 parts of tert-butyl methyl ether was added to the resulting concentrate and stirred. The resulting supernatant was removed and concentrated. The obtained concentrate was dissolved in acetonitrile and then concentrated to obtain 2.83 parts of the salt represented by the formula (I-4).
MASS (ESI (+) Spectrum): M ⁺ 263.1
MASS (ESI (−) Spectrum): M ^- 533.1

式（Ｉ−１４−ｇ）で表される塩３．８２部及びアセトニトリル１９．１２部を、反応器に仕込み、２３℃で３０分間攪拌した。その後、式（Ｉ−１４−ｂ）で表される化合物１．５２部を添加し、７０℃程度まで昇温した後、同温度で２時間攪拌し、式（Ｉ−１４−ｈ）で表される化合物を含む溶液を得た。得られた式（Ｉ−１４−ｈ）で表される化合物を含む溶液に、５０℃で、式（Ｉ−４−ｆ）で表される化合物２．６９部及びクロロホルム８．０７部の混合溶液を１時間かけて滴下し、さらに、６０℃で１２時間攪拌した後、得られた反応物を濃縮した。得られた濃縮物に、クロロホルム７０部及び２％シュウ酸水５０部を加え、２３℃で３０分間攪拌した。その後、静置し、分液して有機層を得た。得られた有機層に、イオン交換水３５部を加え、２３℃で３０分間攪拌した。その後、静置し、分液して有機層を得た。この水洗操作をさらに５回繰り返した。水洗後の有機層に活性炭１．００部を仕込み、２３℃で３０分間攪拌し、ろ過した。ろ液を濃縮し、得られた濃縮物に、ｔｅｒｔ−ブチルメチルエーテル２０部を加えて攪拌した。得られた上澄液を除去し、濃縮した。得られた濃縮物をアセトニトリルに溶解した後、濃縮することにより、式（Ｉ−１４）で表される塩２．９８部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ３０５．１
ＭＡＳＳ（ＥＳＩ（−）Ｓｐｅｃｔｒｕｍ）：Ｍ⁻ ５３３．１ Example 3: Synthesis of salt represented by formula (I-14)

3.82 parts of the salt represented by the formula (I-14-g) and 19.12 parts of acetonitrile were charged into a reactor and stirred at 23 ° C. for 30 minutes. Thereafter, 1.52 parts of the compound represented by the formula (I-14-b) was added, and the temperature was raised to about 70 ° C., followed by stirring at the same temperature for 2 hours, and represented by the formula (I-14-h). A solution containing the compound to be obtained was obtained. The solution containing the compound represented by the formula (I-14-h) thus obtained was mixed with 2.69 parts of the compound represented by the formula (I-4-f) and 8.07 parts of chloroform at 50 ° C. The solution was added dropwise over 1 hour, and the mixture was further stirred at 60 ° C. for 12 hours, and then the obtained reaction product was concentrated. To the obtained concentrate, 70 parts of chloroform and 50 parts of 2% oxalic acid water were added and stirred at 23 ° C. for 30 minutes. Then, it left still and liquid-separated and obtained the organic layer. To the obtained organic layer, 35 parts of ion-exchanged water was added and stirred at 23 ° C. for 30 minutes. Then, it left still and liquid-separated and obtained the organic layer. This washing operation was further repeated 5 times. The organic layer after washing with water was charged with 1.00 parts of activated carbon, stirred at 23 ° C. for 30 minutes, and filtered. The filtrate was concentrated, and 20 parts of tert-butyl methyl ether was added to the resulting concentrate and stirred. The resulting supernatant was removed and concentrated. The obtained concentrate was dissolved in acetonitrile and then concentrated to obtain 2.98 parts of the salt represented by the formula (I-14).
MASS (ESI (+) Spectrum): M ⁺ 305.1
MASS (ESI (−) Spectrum): M ^- 533.1

以下、これらの化合物をその式番号に応じて、「モノマー（ａ１−１−２）」などという。 Synthesis of Resin (A) The compounds used for the synthesis of resin (A) are shown below.

Hereinafter, these compounds are referred to as “monomer (a1-1-2)” or the like according to the formula number.

Synthesis Example 1: [Synthesis of Resin A1]
The monomer (a1-1-3), the monomer (a1-2-3), the monomer (a2-1-1), the monomer (a3-1-1) and the monomer (a3-2-3) are mixed in a molar ratio [ Monomer (a1-1-3): monomer (a1-2-3): monomer (a2-1-1): monomer (a3-1-1): monomer (a3-2-3)] is 30:14 : 6: 20: 30 The mixture was further mixed, and 1.5 mass times of dioxane was further mixed with this monomer mixture with respect to the total mass of all monomers. Into the obtained mixture, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were respectively added to 1.00 mol% and 3.00 mol% with respect to the total number of moles of all monomers. It added so that it might become. This was polymerized by heating at 73 ° C. for about 5 hours. Thereafter, the polymerization reaction solution was poured into a large amount of a mixed solvent of methanol and water (mass ratio methanol: water = 4: 1) to precipitate the resin. This resin was filtered and collected. It is again dissolved in dioxane, poured into a mixed solvent of a large amount of methanol and water to precipitate the resin, and the precipitated resin is filtered and collected twice to perform reprecipitation purification, and the weight average molecular weight is 8 the copolymer is .1 × 10 ³ was obtained in a yield of 65%. This copolymer is monomer (a1-1-3), monomer (a1-2-3), monomer (a2-1-1), monomer (a3-1-1), monomer (a3-2-3). These have the following structural units derived from each, and this is designated as resin A1.

Synthesis Example 2: [Synthesis of Resin A2]
Monomer (a1-1-2), monomer (a1-2-3), monomer (a2-1-1), monomer (a3-1-1) and monomer (a3-2-3) are mixed in a molar ratio [ Monomer (a1-1-2): monomer (a1-2-3): monomer (a2-1-1): monomer (a3-1-1): monomer (a3-2-3)] is 30:14 : 6: 20: 30 The mixture was further mixed, and 1.5 mass times of dioxane was further mixed with this monomer mixture with respect to the total mass of all monomers. Into the obtained mixture, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were respectively added to 1.00 mol% and 3.00 mol% with respect to the total number of moles of all monomers. It added so that it might become. This was polymerized by heating at 73 ° C. for about 5 hours. Thereafter, the polymerization reaction solution was poured into a large amount of a mixed solvent of methanol and water (mass ratio methanol: water = 4: 1) to precipitate the resin. This resin was filtered and collected. Again, it is dissolved in dioxane, poured into a large amount of methanol / water mixed solvent to precipitate the resin, and the precipitated resin is filtered and collected twice to perform reprecipitation purification, and the weight average molecular weight is 7 A copolymer of .8 × 10 ³ was obtained with a yield of 68%. This copolymer is monomer (a1-1-2), monomer (a1-2-3), monomer (a2-1-1), monomer (a3-1-1), monomer (a3-2-3). These have the following structural units derived from each, and this is designated as resin A2.

Synthesis Example 3: [Synthesis of Resin A3]
Monomer (1-1-2), monomer (a2-1-1) and monomer (a3-1-1) are mixed in a molar ratio [monomer (1-1-2): monomer (a2-1-1): Monomer (a3-1-1)] was mixed so as to be 50:25:25, and 1.5 mass times dioxane was further mixed with respect to the total mass of all monomers. To the obtained mixture, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) were added as initiators in proportions of 1 mol% and 3 mol%, respectively, with respect to the total number of moles of all monomers. Then, this was heated at 80 ° C. for about 8 hours to carry out polymerization. Thereafter, the polymerization reaction solution was poured into a large amount of a mixed solvent of methanol and water (mass ratio methanol: water = 4: 1) to precipitate the resin. This resin was filtered and collected. Again, the obtained resin is dissolved in dioxane, poured into a large amount of methanol / water mixed solvent to precipitate the resin, and the precipitated resin is filtered and recovered three times for reprecipitation purification. A copolymer having a weight average molecular weight of about 9.2 × 10 ³ was obtained in a yield of 60%. This copolymer has structural units derived from the following monomers derived from the monomer (1-1-2), the monomer (a2-1-1) and the monomer (a3-1-1), respectively. Yes, this is resin A3.

Synthesis Example 4 [Synthesis of Resin A4]
As the monomer, using monomer (a1-1-3), monomer (a1-2-3), monomer (a2-1-1), monomer (a3-2-3) and monomer (a3-1-1), The molar ratio (monomer (a1-1-3): monomer (a1-2-3): monomer (a2-1-1): monomer (a3-2-3): monomer (a3-1-1)) , 30: 14: 6: 20: 30, and 1.5 mass times dioxane of the total monomer amount was added to make a solution. To this solution, 1 mol% and 3 mol% of azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added to the total monomer amount, respectively, and these were heated at 75 ° C. for about 5 hours. did. The obtained reaction mixture was poured into a large amount of methanol / water mixed solvent to precipitate the resin, and this resin was filtered. The obtained resin was dissolved again in dioxane, and the resulting solution was poured into a methanol / water mixed solvent to precipitate the resin, followed by two reprecipitation operations of filtering the resin, and a weight average molecular weight of 7.0. A × 10 ³ resin A4 (copolymer) was obtained in a yield of 60%. This resin A4 has the following structural units.

Synthesis Example 5 [Synthesis of Resin A5]
As the monomer, using monomer (a1-1-3), monomer (a1-5-1), monomer (a2-1-1), monomer (a3-2-3) and monomer (a3-1-1), The molar ratio (monomer (a1-1-3): monomer (a1-5-1): monomer (a2-1-1): monomer (a3-2-3): monomer (a3-1-1)) , 30: 14: 6: 20: 30, and 1.5 mass times dioxane of the total monomer amount was added to make a solution. To this solution, 1 mol% and 3 mol% of azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added to the total monomer amount, respectively, and these were heated at 75 ° C. for about 5 hours. did. The obtained reaction mixture was poured into a large amount of methanol / water mixed solvent to precipitate the resin, and this resin was filtered. The obtained resin was again dissolved in dioxane, and the resulting solution was poured into a methanol / water mixed solvent to precipitate the resin, followed by two reprecipitation operations of filtering the resin, and a weight average molecular weight of 7.4. × give 10 ^third resin A5 (copolymer) in 62% yield. This resin A5 has the following structural units.

Synthesis Example 6 [Synthesis of Resin X1]
Monomer (a4-1-7) was used as a monomer, and 1.5 mass times dioxane of the total monomer amount was added to prepare a solution. Azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added to the solution in an amount of 0.7 mol% and 2.1 mol%, respectively, with respect to the total monomer amount, and these were added at 75 ° C. Heated for about 5 hours. The obtained reaction mixture was poured into a large amount of methanol / water mixed solvent to precipitate the resin, and this resin was filtered.
The resin thus obtained was dissolved again in dioxane, and the solution obtained by pouring the solution into a methanol / water mixed solvent was precipitated twice, and the resin was filtered twice to perform the reprecipitation operation twice. 8 × 10 ⁴ resin X1 was obtained with a yield of 77%. This resin X1 has the following structural units.

Examples 4 to 15 and Comparative Example 1: Preparation of Resist Composition As shown in Table 7, the components were mixed and dissolved, and further filtered through a fluororesin filter having a pore size of 0.2 μm to obtain a resist composition. Prepared.

Ｂ１−１１：

<Acid generator>
I-1: Salt represented by formula (I-1) I-4: Salt represented by formula (I-4) I-14: Salt represented by formula (I-14) B1-3:

B1-11:

<Resin>
A1: Resin A1
A2: Resin A2
A3: Resin A3
A4: Resin A4
A5: Resin A5
X1: Resin X1
<Basic compound: Quencher>
C1: 2,6-Diisopropylaniline

＜溶剤＞
プロピレングリコールモノメチルエーテルアセテート ２６５．０部
プロピレングリコールモノメチルエーテル ２０．０部
２−ヘプタノン ２０．０部
γ−ブチロラクトン ３．５部

<Solvent>
Propylene glycol monomethyl ether acetate 265.0 parts Propylene glycol monomethyl ether 20.0 parts 2-heptanone 20.0 parts γ-butyrolactone 3.5 parts

<Manufacture of resist pattern and its evaluation>
An organic antireflection film having a thickness of 780 mm is formed by applying a composition for organic antireflection film (ARC-29; manufactured by Nissan Chemical Co., Ltd.) to a silicon wafer and baking it at 205 ° C. for 60 seconds. Formed. Subsequently, the resist composition was spin-coated on the organic antireflection film so that the film thickness after drying (pre-baking) was 85 nm. The silicon wafer coated with the resist composition was pre-baked on a direct hot plate at a temperature described in the column “PB” in Table 4 for 60 seconds to form a resist film (composition layer). ArF excimer laser stepper for immersion exposure (XT: 1900 Gi; manufactured by ASML, NA = 1.35, 3/4 Annular XY polarized light) on a silicon wafer on which a resist film is formed, and a contact hole pattern (hole pitch 95 nm) Using a mask for forming a hole diameter of 60 nm), the exposure amount was changed stepwise. Note that ultrapure water was used as the immersion medium.
After the exposure, the silicon wafer was post-exposure baked on a hot plate for 60 seconds at the temperature described in the “PEB” column of Table 4. Next, this silicon wafer was subjected to paddle development for 60 seconds with a 2.38% tetramethylammonium hydroxide aqueous solution to obtain a resist pattern.

  In resist pattern formation from each resist composition, the exposure amount at which the hole diameter of a resist pattern formed using a mask having a mask hole diameter of 60 nm was 50 nm was defined as effective sensitivity.

  In manufacturing the resist pattern as described above, the following items were evaluated.

Mask error factor (MEF) evaluation: With regard to effective sensitivity, resist patterns were formed with masks having mask hole diameters of 62 nm, 61 nm, 60 nm, 59 nm, and 58 nm, respectively (pitch is 95 nm). The mask hole diameter was plotted on the horizontal axis, and the hole diameter of the resist pattern formed from the mask of each mask hole diameter was plotted on the vertical axis, and the slope of the regression line obtained from the plot was calculated as MEF. Tilt is
◎ less than 2.5
○ from 2.5 to 3.0
A value larger than 3.0 was judged as x.

  By using the acid generator containing the salt (I) of the present invention as an active ingredient in a resist composition containing the acid generator, a resist pattern can be produced with an excellent mask error factor (MEF). Therefore, the salt (I) of the present invention is extremely useful for fine processing of semiconductors.

Claims (10)

A salt represented by the formula (I).

[In the formula (I),
Q ¹ and Q ² are the same or different and each represents a fluorine atom or a C 1-6 perfluoroalkyl group.
L ¹ represents a divalent aliphatic saturated hydrocarbon group having 1 to 17 carbon atoms, and the methylene group constituting the divalent aliphatic saturated hydrocarbon group may be replaced by an oxygen atom or a carbonyl group. .
L ² represents a divalent aliphatic saturated hydrocarbon group having 1 to 6 carbon atoms, and the methylene group constituting the divalent aliphatic saturated hydrocarbon group is an oxygen atom, a carbonyl group, or —NR ² —. It may be replaced.
R ² represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
Ring W represents an aliphatic ring having 3 to 36 carbon atoms, and a methylene group constituting the aliphatic ring may be replaced with an oxygen atom, a sulfur atom, a carbonyl group, or a sulfonyl group. The hydrogen atom contained is a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms, or an aromatic hydrocarbon having 6 to 10 carbon atoms. It may be substituted with a group.
R ¹ is a monovalent organic group containing a fluorine-substituted aromatic ring, and the organic group may have a substituent.
Z ⁺ represents an organic counter ion. ] The salt according to claim 1, wherein R ^{1 in the} formula (I) is an organic group represented by the formula (R ¹ -1) or the formula (R ¹ -2).

(* Represents a bond with L ² ) Of the formula (I)

The partial structure represented by
The salt according to claim 1 or 2, which has a structure represented by any one of formula (Ia1-1), formula (Ia1-2) or formula (Ia1-3).

[In the formula (Ia1-1),
The methylene group constituting the adamantane ring may be replaced by an oxygen atom, a sulfur atom, a carbonyl group or a sulfonyl group, and the hydrogen atom contained in the adamantane ring is a hydroxy group, an alkyl group having 1 to 12 carbon atoms, a carbon number It may be substituted with an alkoxy group having 1 to 12, an alicyclic hydrocarbon group having 3 to 12 carbon atoms, or an aromatic hydrocarbon group having 6 to 10 carbon atoms. ]

[In the formula (Ia1-2),
The methylene group constituting the cyclohexane ring may be replaced with an oxygen atom, a sulfur atom, a carbonyl group or a sulfonyl group. The hydrogen atom contained in the cyclohexane ring is a hydroxy group, an alkyl group having 1 to 12 carbon atoms, or a carbon number. It may be substituted with an alkoxy group having 1 to 12, an alicyclic hydrocarbon group having 3 to 12 carbon atoms, or an aromatic hydrocarbon group having 6 to 10 carbon atoms. ]

[In Formula (Ia1-3), the methylene group constituting the ring may be replaced by an oxygen atom, a sulfur atom, a carbonyl group or a sulfonyl group, and the hydrogen atom contained in the norbornane ring is a hydroxy group, a carbon number It may be substituted with an alkyl group having 1 to 12, an alkoxy group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms, or an aromatic hydrocarbon group having 6 to 10 carbon atoms. ] L ^{1 in the} formula (I) is
_{* -CO-O- (CH 2)} u -
(U represents an integer of 0 to 6. * represents a bond with a carbon atom bonded to Q ¹ and Q ² .
The salt according to any one of claims 1 to 3. L ^{2 in the} formula (I) is
_{* -CO-O- (CH 2)} v - or _* -O-CH 2 -CO-O-
(V represents an integer of 0 to 4. * represents a bond with the ring W.)
The salt according to any one of claims 1 to 4. The salt according to any one of claims 1 to 5, wherein Z ⁺ is a triarylsulfonium cation.   The acid generator which contains the salt in any one of Claims 1-6 as an active ingredient. An acid generator according to claim 7;
A resist composition containing a resin that is insoluble or hardly soluble in an alkaline aqueous solution and that can be dissolved in an alkaline aqueous solution by the action of an acid.   The resist composition according to claim 8, further comprising a basic compound. (1) The process of apply | coating the resist composition of Claim 8 or 9 on a board | substrate,
(2) The process of drying the composition after application | coating and forming a composition layer,
(3) a step of exposing the composition layer,
(4) a step of heating the composition layer after exposure, and (5) a step of developing the composition layer after heating,
A method for producing a resist pattern including: