JP2011102959A - Resist composition and pattern forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resist composition which forms a pattern having an excellent shape and DOF. <P>SOLUTION: The resist composition includes an acid generator (A) having a salt represented by formula (I) as an effective component and a resin (B) having a repeating unit derived from a compound represented by formula (aa). In the formula (I), Q<SP>1</SP>and Q<SP>2</SP>represent F or perfluoroalkyl; X<SP>1</SP>represents a divalent saturated hydrocarbon group which may have a substituent, -CH<SB>2</SB>- in the group may be substituted by -O- or -CO-; Y<SP>1</SP>represents an aliphatic hydrocarbon which may have a substituent or the like, -CH<SB>2</SB>- in the group may be substituted by -CO-, -O- or the like; R<SP>c</SP>represents H or alkyl; Z<SP>+</SP>represents an organic counter cation; T represents an alicyclic hydrocarbon group which may have a substituent, -CH<SB>2</SB>- contained in the group has been substituted by at least one -SO<SB>2</SB>-; and R<SP>1</SP>represents H, a halogen atom or alkyl which may have a halogen atom. In the formula (aa), T represents a 4C-36C alicyclic hydrocarbon group; R<SP>c</SP>represents H or 1C-6C alkyl; and R<SP>1</SP>represents H, a halogen atom or 1C-6C alkyl which may have a halogen atom. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a resist composition and a pattern forming method.

A resist composition used for fine processing of a semiconductor using a lithography technique contains a salt that generates an acid upon exposure and a resin.

In Patent Document 1, the following monomer A, monomer J, and monomer G are charged in a molar ratio of 52.6: 15.8: 31.6 and polymerized, and acid generation represented by Y1 below A resist composition containing an agent is described.

JP 2009-62491 A

  In the conventional resist composition, the pattern shape and DOF obtained may not always be satisfactory.

［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。
Ｘ^１は、置換基を有していてもよい炭素数１〜１７の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる−ＣＨ_２−は、−Ｏ−又は−ＣＯ−で置き換わっていてもよい。
Ｙ^１は、炭素数１〜３６の脂肪族炭化水素基、炭素数３〜３６の脂環式炭化水素基又は炭素数６〜３６の芳香族炭化水素基であり、該脂肪族炭化水素基、脂環式炭化水素基及び芳香族炭化水素基は、置換基を有していてもよく、該脂肪族炭化水素基及び該脂環式炭化水素基に含まれる−ＣＨ_２−は、−ＣＯ−、−Ｏ−、−Ｓ−、−ＳＯ_２−又は−Ｎ（Ｒ^ｃ）−で置き換わっていてもよい。
Ｒ^ｃは、水素原子又は炭素数１〜６のアルキル基を表す。
Ｚ^＋は、有機対カチオンを表す。］

［式（ａａ）中、
Ｔは、炭素数４〜３６の脂環式炭化水素基を表し、該脂環式炭化水素基に含まれる水素原子は、ハロゲン原子、水酸基、ハロゲン原子又は水酸基で置換されていてもよい炭素数１〜１２のアルキル基、炭素数１〜１２のアルコキシ基、炭素数６〜１２のアリール基、炭素数７〜１２のアラルキル基、グリシジルオキシ基、炭素数２〜４のアシル基、アルコキシカルボニル基、アルカノイルオキシアルキル基又はシアノ基で置換されていてもよく、該脂環式炭化水素基に含まれる−ＣＨ_２−は、少なくとも１つの−ＳＯ_２−で置き換わっており、さらに、−ＣＯ−、−Ｏ−、−Ｓ−、−ＳＯ_２−又は−Ｎ（Ｒ^ｃ）−で置き換わっていてもよい。
Ｒ^ｃは、水素原子又は炭素数１〜６のアルキル基を表す。
Ｒ^１は、水素原子、ハロゲン原子またはハロゲン原子を有してもよい炭素数１〜６のアルキル基を表す。］ The present invention includes the following inventions.
[1] A resist composition containing an acid generator (A) containing a salt represented by formula (I) as an active ingredient and a resin (B) having a repeating unit derived from a compound represented by formula (aa) .

[In the formula (I),
Q ¹ and Q ² each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group.
X ¹ represents a C 1-17 divalent saturated hydrocarbon group which may have a substituent, and —CH ₂ — contained in the saturated hydrocarbon group is —O— or —CO—. It may be replaced with.
Y ¹ is an aliphatic hydrocarbon group having 1 to 36 carbon atoms, an alicyclic hydrocarbon group having 3 to 36 carbon atoms, or an aromatic hydrocarbon group having 6 to 36 carbon atoms, the aliphatic hydrocarbon group, The alicyclic hydrocarbon group and the aromatic hydrocarbon group may have a substituent, and —CH ₂ — contained in the aliphatic hydrocarbon group and the alicyclic hydrocarbon group is —CO—. , —O—, —S—, —SO ₂ — or —N (R ^c ) — may be substituted.
R ^c represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
Z ⁺ represents an organic counter cation. ]

[In the formula (aa)
T represents an alicyclic hydrocarbon group having 4 to 36 carbon atoms, and the hydrogen atom contained in the alicyclic hydrocarbon group may be substituted with a halogen atom, a hydroxyl group, a halogen atom or a hydroxyl group. An alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, a glycidyloxy group, an acyl group having 2 to 4 carbon atoms, and an alkoxycarbonyl group , An alkanoyloxyalkyl group or a cyano group, and —CH ₂ — contained in the alicyclic hydrocarbon group is replaced by at least one —SO ₂ —, and —CO—, -O -, - S -, - SO 2 - or -N ^{(R c)} - it may be replaced by.
R ^c represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
R ¹ represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom. ]

［式（Ｔ１）中、
環に含まれる水素原子は、ハロゲン原子、水酸基、ハロゲン原子又は水酸基で置換されていてもよい炭素数１〜１２のアルキル基、炭素数１〜１２のアルコキシ基、炭素数６〜１２のアリール基、炭素数７〜１２のアラルキル基、グリシジルオキシ基、炭素数２〜４のアシル基、アルコキシカルボニル基、アルカノイルオキシアルキル基又はシアノ基で置換されていてもよく、環に含まれる−ＣＨ_２−は、少なくとも１つの−ＳＯ_２−で置き換わっており、さらに、−ＣＯ−、−Ｏ−、−Ｓ−、−ＳＯ_２−又は−Ｎ（Ｒ^ｃ）−で置き換わっていてもよい。
Ｒ^ｃは、上記と同じ意味を表す。
＊は、酸素原子との結合手を表す。
Ｔ^１は、酸素原子又は−ＣＨ_２−を表す。］ [2] The resist composition according to [1], wherein T is a group represented by the formula (T1).

[In the formula (T1),
The hydrogen atom contained in the ring is a halogen atom, a hydroxyl group, an alkyl group having 1 to 12 carbon atoms which may be substituted with a halogen atom or a hydroxyl group, an alkoxy group having 1 to 12 carbon atoms, or an aryl group having 6 to 12 carbon atoms. , An aralkyl group having 7 to 12 carbon atoms, a glycidyloxy group, an acyl group having 2 to 4 carbon atoms, an alkoxycarbonyl group, an alkanoyloxyalkyl group, or a cyano group, and —CH ₂ — included in the ring Is replaced by at least one —SO ₂ —, and may be further replaced by —CO—, —O—, —S—, —SO ₂ — or —N (R ^c ) —.
R ^c represents the same meaning as described above.
* Represents a bond with an oxygen atom.
T ¹ represents an oxygen atom or —CH ₂ —. ]

［式（Ｔ２）中、
環に含まれる水素原子は、ハロゲン原子、水酸基、ハロゲン原子又は水酸基で置換されていてもよい炭素数１〜１２のアルキル基、炭素数１〜１２のアルコキシ基、炭素数６〜１２のアリール基、炭素数７〜１２のアラルキル基、グリシジルオキシ基、炭素数２〜４のアシル基、アルコキシカルボニル基、アルカノイルオキシアルキル基又はシアノ基で置換されていてもよく、環に含まれる−ＣＨ_２−は、カルボニル基、酸素原子、硫黄原子、−ＳＯ_２−又は−Ｎ（Ｒ^ｃ）−で置き換わっていてもよい。
Ｒ^ｃ及び＊は、上記と同じ意味を表す。］ [3] The resist composition of [1] or [2], wherein T is a group represented by the formula (T2).

[In the formula (T2),
The hydrogen atom contained in the ring is a halogen atom, a hydroxyl group, an alkyl group having 1 to 12 carbon atoms which may be substituted with a halogen atom or a hydroxyl group, an alkoxy group having 1 to 12 carbon atoms, or an aryl group having 6 to 12 carbon atoms. , An aralkyl group having 7 to 12 carbon atoms, a glycidyloxy group, an acyl group having 2 to 4 carbon atoms, an alkoxycarbonyl group, an alkanoyloxyalkyl group, or a cyano group, and —CH ₂ — included in the ring May be replaced by a carbonyl group, an oxygen atom, a sulfur atom, —SO ₂ — or —N (R ^c ) —.
R ^c and * represent the same meaning as described above. ]

  [4] The resin (B) is a resin further having an acid labile group, insoluble or hardly soluble in an aqueous alkali solution, and soluble in an aqueous alkali solution by the action of an acid. 3] The resist composition.

  [5] The resist composition according to any one of [1] to [4], further containing a basic compound.

［式（ａａ）中、
Ｔは、炭素数４〜３６の脂環式炭化水素基を表し、該脂環式炭化水素基に含まれる水素原子は、ハロゲン原子、水酸基、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６〜１２のアリール基、炭素数７〜１２のアラルキル基、グリシジルオキシ基又は炭素数２〜４のアシル基で置換されていてもよく、該脂環式炭化水素基に含まれる−ＣＨ_２−は、少なくとも１つの−ＳＯ_２−で置換されており、さらに、カルボニル基、酸素原子、硫黄原子、−ＳＯ_２−又は−Ｎ（Ｒ^ｃ）−で置換されていてもよい。
Ｒ^ｃは、水素原子又は炭素数１〜６のアルキル基を表す。
Ｒ^１は、水素原子、ハロゲン原子またはハロゲン原子を有してもよい炭素数１〜６のアルキル基を表す。］ [6] (1) The process of apply | coating the resist composition containing resin (B) which has a repeating unit derived from the compound represented by Formula (aa) on a board | substrate,
(2) a step of removing the solvent from the composition after coating to form a composition layer;
(3) a step of exposing the composition layer using an exposure machine;
(4) A step of heating the composition layer after exposure,
(5) A pattern forming method including a step of developing the heated composition layer using a developing device.

[In the formula (aa)
T represents an alicyclic hydrocarbon group having 4 to 36 carbon atoms, and the hydrogen atom contained in the alicyclic hydrocarbon group includes a halogen atom, a hydroxyl group, an alkyl group having 1 to 12 carbon atoms, and 1 to 1 carbon atoms. The alicyclic hydrocarbon group may be substituted with an alkoxy group having 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, a glycidyloxy group, or an acyl group having 2 to 4 carbon atoms. —CH ₂ — contained in is substituted with at least one —SO ₂ —, and further substituted with a carbonyl group, an oxygen atom, a sulfur atom, —SO ₂ — or —N (R ^c ) —. Also good.
R ^c represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
R ¹ represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom. ]

［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。
Ｘ^１は、置換基を有していてもよい炭素数１〜１７の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる−ＣＨ_２−は、−Ｏ−又は−ＣＯ−で置き換わっていてもよい。
Ｙ^１は、炭素数１〜３６の脂肪族炭化水素基、炭素数３〜３６の脂環式炭化水素基又は炭素数６〜３６の芳香族炭化水素基であり、該脂肪族炭化水素基、脂環式炭化水素基及び芳香族炭化水素基は、置換基を有していてもよく、該脂肪族炭化水素基及び該脂環式炭化水素基に含まれる−ＣＨ_２−は、−ＣＯ−、−Ｏ−、−Ｓ−、−ＳＯ_２−又は−Ｎ（Ｒ^ｃ）−で置き換わっていてもよい。
Ｒ^ｃは、水素原子又は炭素数１〜６のアルキル基を表す。
Ｚ^＋は、有機対カチオンを表す。］ [7] The pattern forming method according to [6], wherein the resist composition further contains an acid generator (A) containing a salt represented by formula (I) as an active ingredient.

[In the formula (I),
Q ¹ and Q ² each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group.
X ¹ represents a C 1-17 divalent saturated hydrocarbon group which may have a substituent, and —CH ₂ — contained in the saturated hydrocarbon group is —O— or —CO—. It may be replaced with.
Y ¹ is an aliphatic hydrocarbon group having 1 to 36 carbon atoms, an alicyclic hydrocarbon group having 3 to 36 carbon atoms, or an aromatic hydrocarbon group having 6 to 36 carbon atoms, the aliphatic hydrocarbon group, The alicyclic hydrocarbon group and the aromatic hydrocarbon group may have a substituent, and —CH ₂ — contained in the aliphatic hydrocarbon group and the alicyclic hydrocarbon group is —CO—. , —O—, —S—, —SO ₂ — or —N (R ^c ) — may be substituted.
R ^c represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
Z ⁺ represents an organic counter cation. ]

  According to the resist composition of the present invention, a pattern having an excellent shape and DOF can be formed.

In this specification, unless otherwise specified, specific chemical substituents described later can be applied to any chemical structural formula having the same substituents while appropriately selecting the number of carbon atoms. Those which can take any of linear, branched or cyclic are included unless otherwise specified, and in the same group, linear, branched and / or cyclic partial structures are mixed. It may be. When stereoisomers exist, all of those stereoisomers are included.
Further, "(meth) acrylic monomer" means at least one monomer having a structure of "CH ₂ = CH-CO-" or _{"CH 2 = C (CH 3)} -CO- ". 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.

［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。
Ｘ^１は、置換基を有していてもよい炭素数１〜１７の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる−ＣＨ_２−は、−Ｏ−又は−ＣＯ−で置き換わっていてもよい。
Ｙ^１は、炭素数１〜３６の脂肪族炭化水素基、炭素数３〜３６の脂環式炭化水素基又は炭素数６〜３６の芳香族炭化水素基であり、該脂肪族炭化水素基、脂環式炭化水素基及び芳香族炭化水素基は、置換基を有していてもよく、該脂肪族炭化水素基及び該脂環式炭化水素基に含まれる−ＣＨ_２−は、−ＣＯ−、−Ｏ−、−Ｓ−、−ＳＯ_２−又は−Ｎ（Ｒ^ｃ）−で置き換わっていてもよい。
Ｒ^ｃは、水素原子又は炭素数１〜６のアルキル基を表す。
Ｚ^＋は、有機対カチオンを表す。］ The resist composition of the present invention comprises an acid generator (A) containing a salt represented by formula (I) as an active ingredient, and a resin (B) having a repeating unit derived from a compound represented by formula (aa) Containing.
<Salt represented by formula (I) (hereinafter sometimes referred to as salt (I))>

[In the formula (I),
Q ¹ and Q ² each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group.
X ¹ represents a C 1-17 divalent saturated hydrocarbon group which may have a substituent, and —CH ₂ — contained in the saturated hydrocarbon group is —O— or —CO—. It may be replaced with.
Y ¹ is an aliphatic hydrocarbon group having 1 to 36 carbon atoms, an alicyclic hydrocarbon group having 3 to 36 carbon atoms, or an aromatic hydrocarbon group having 6 to 36 carbon atoms, the aliphatic hydrocarbon group, The alicyclic hydrocarbon group and the aromatic hydrocarbon group may have a substituent, and —CH ₂ — contained in the aliphatic hydrocarbon group and the alicyclic hydrocarbon group is —CO—. , —O—, —S—, —SO ₂ — or —N (R ^c ) — may be substituted.
R ^c represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
Z ⁺ represents an organic counter cation. ]

  Examples of perfluoroalkyl groups include perfluoromethyl group, perfluoroethyl group, perfluoro-n-propyl group, perfluoroisopropyl group, perfluoro-n-butyl group, perfluoro-sec-butyl group, perfluoro-tert-butyl group, perfluoro-n- A pentyl group, a perfluoro-n-hexyl group, etc. are mentioned. Of these, a perfluoromethyl group is preferable.

Examples of the saturated hydrocarbon group include divalent groups including an alkylene group having 1 to 17 carbon atoms and a cycloalkylene group.
Examples of the alkylene group include a methylene group, an ethylene group, a propylene group, an isopropylene group, a sec-butylene group, and a tert-butylene group.

［式（Ｘ^１−Ａ）〜式（Ｘ^１−Ｃ）中、
Ｘ^１Ａ及びＸ^１Ｂは、それぞれ独立に、置換基を有していてもよい炭素数１〜６のアルキレン基を表し、該アルキレン基に含まれる−ＣＨ_２−は、−Ｏ−又は−ＣＯ−で置き換わっていてもよい。ただし、式（Ｘ^１−Ａ）〜式（Ｘ^１−Ｃ）で表される基の炭素数は１〜１７である。］ Examples of the divalent group containing a cycloalkylene group include groups represented by the formula (X ¹ -A) to the formula (X ¹ -C).

[In the formula (X ¹ -A) to formula (X ¹ -C),
X ^1A and X ^1B each independently represents an optionally substituted alkylene group having 1 to 6 carbon atoms, and —CH ₂ — contained in the alkylene group is —O— or —CO—. It may be replaced with. However, the number of carbon atoms of the group represented by the formula ^(X 1 -A) ~ Formula ^(X 1 -C) is 1 to 17. ]

Examples of the aliphatic hydrocarbon group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, heptyl. And alkyl groups such as 2-ethylhexyl group, octyl group, nonyl group, decyl group, undecyl group and dodecyl group.
Examples of the alicyclic hydrocarbon group include cycloalkyl such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclononyl group, cyclodecyl group, norbornyl group, adamantyl group, and isobornyl group. Groups.

  As an aromatic hydrocarbon group, aryl groups, such as a phenyl group, a naphthyl group, an anthranyl group, etc. are mentioned, for example.

In the anion of the salt represented by the formula (I) as the active ingredient of the acid generator (A), Q ¹ and Q ² are preferably each independently a fluorine atom or —CF ₃ , and both are fluorine atoms. Is more preferable.

Examples of the substituent in X ¹ include a halogen atom, a hydroxyl group, a carboxyl group, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, and an aromatic group having 6 to 20 carbon atoms. Examples thereof include a hydrocarbon group, an aralkyl group having 7 to 21 carbon atoms, a glycidyloxy group, and an acyl group having 2 to 4 carbon atoms.

Examples of the halogen atom include fluorine, chlorine, bromine and iodine atoms.
Examples of the aralkyl group include benzyl, phenethyl, phenylpropyl, trityl, naphthylmethyl group, naphthylethyl group, and the like.
Examples of the acyl group include an acetyl group, a propionyl group, and a butyryl group.

X ¹ represents —CO—O—X ¹⁰ —, —CO—O—X ¹⁰ —CO—O—, —X ¹⁰ —O—CO—, —X ¹⁰ —O—X ¹¹ —, —CO—O—. (X ¹¹ —O) _y —X ¹⁰ — is suitable. ^{Especially, -CO-O-X 10 -} , - CO-O-X 10 -CO-O -, - CO-O- (X 11 -O) y -X 10 - are preferred.
^{However, X 10} and ^{X 11} represents a single bond or an alkylene group having 1 to 16 carbon atoms. y is an integer of 0-2.

Specific examples of X ¹ include the following groups.

Examples of the substituent that may be substituted with the aliphatic hydrocarbon group, alicyclic hydrocarbon group, and aromatic hydrocarbon group of Y ¹ include, for example, a halogen atom (excluding a fluorine atom), a hydroxyl group, and a carbon number of 1 to 12 aliphatic hydrocarbon groups, alkoxy groups having 1 to 12 carbon atoms, aromatic hydrocarbon groups having 6 to 20 carbon atoms, aralkyl groups having 7 to 21 carbon atoms, glycidyloxy groups, and acyl groups having 2 to 4 carbon atoms 1 or more selected from the group consisting of.

As the alkoxy group, methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, sec-butoxy group, tert-butoxy group, n-pentyloxy group, n-hexyloxy group, heptyloxy group Octyloxy group, 2-ethylhexyloxy group, nonyloxy group, decyloxy group, undecyloxy group, dodecyloxy group and the like.
Among these, Y ¹ is suitably an alicyclic hydrocarbon group having 4 to 36 carbon atoms which may have a substituent.

［式（Ｙ１）中、
環Ｗ’は、炭素数３〜３６の脂環式炭化水素基を表し、該脂環式炭化水素基に含まれる−ＣＨ_２−は、−ＣＯ−、−Ｏ−、−Ｓ−、−ＳＯ_２−又は−Ｎ（Ｒ^ｃ）−で置き換わっていてもよい。
Ｒ^ｂは、互いに独立に、ハロゲン原子、直鎖状又は分岐状の炭素数１〜１２の脂肪族炭化水素基、炭素数６〜２０の芳香族炭化水素基、炭素数７〜２１のアラルキル基、グリシジルオキシ基あるいは炭素数２〜４のアシル基を表す。
ｘは、０〜８の整数を表す。ｘが２以上の場合、複数のＲ^ｂは、同一でも異なってもよい。
Ｒ^ａは、水素原子あるいは直鎖状又は分岐状の炭素数１〜６の炭化水素基を表すか、環Ｗ’に含まれる炭素原子と互いに結合して環を形成していてもよい。
Ｒ^ｃは、水素原子又は炭素数１〜６のアルキル基を表す。] Y ¹ is preferably a group represented by the formula (Y1).

[In the formula (Y1),
Ring W ′ represents an alicyclic hydrocarbon group having 3 to 36 carbon atoms, and —CH ₂ — contained in the alicyclic hydrocarbon group is —CO—, —O—, —S—, —SO. _It may be replaced by _2- or -N (R ^c )-.
R ^b is independently of each other a halogen atom, a linear or branched aliphatic hydrocarbon group having 1 to 12 carbon atoms, an aromatic hydrocarbon group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 21 carbon atoms. Represents a glycidyloxy group or an acyl group having 2 to 4 carbon atoms.
x represents an integer of 0 to 8. When x is 2 or more, the plurality of R ^b may be the same or different.
R ^a represents a hydrogen atom or a linear or branched hydrocarbon group having 1 to 6 carbon atoms, or may be bonded to a carbon atom contained in the ring W ′ to form a ring.
R ^c represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. ]

  Examples of the hydrocarbon group include an aliphatic hydrocarbon, an alicyclic hydrocarbon, an aromatic hydrocarbon, or a group obtained by combining these.

In the formula (Y1), R ^b may be a halogen atom, but does not contain a fluorine atom.
x preferably represents an integer of 0 to 6, more preferably an integer of 0 to 4.
Examples of the ring W ′ include formula (W1) to formula (W50). Of these, groups represented by formulas (W1) to (W19) are preferable, and groups represented by formula (W12), formula (W15), formula (W16), and formula (W19) are more preferable. .

The hydrogen atom contained in the ring W ′ is not substituted or substituted only with a hydrocarbon group (—CH ₂ — contained in the hydrocarbon group may be substituted with an oxygen atom or the like) Y Examples of ¹ include the following groups.

Examples of Y ¹ in which a hydrogen atom contained in ring W ′ is substituted with a hydroxyl group or a group containing a hydroxyl group (however, having no lactone structure) include the following groups.

Examples of Y ¹ having a lactone structure in which two adjacent —CH ₂ — contained in the ring W ′ are substituted with a carbonyl group and an oxygen atom include the following groups.

Examples of Y ¹ having a ketone structure in which one —CH ₂ — contained in the ring W ′ is substituted with a carbonyl group include the following groups.

Examples of Y ¹ in which the hydrogen atom contained in the ring W ′ is substituted with an aromatic hydrocarbon group or a group having an aromatic ring include the following groups.

Examples of Y ¹ having an ether structure in which one —CH ₂ — contained in the ring W ′ is substituted with an oxygen atom include the following groups.

Examples of Y ¹ in which one —CH ₂ — contained in the ring W ′ is substituted with —SO ₂ — include the following groups.

Examples of Y ¹ in which one —CH ₂ — contained in ring W ′ is substituted with an oxygen atom and one —CH ₂ — is substituted with —SO ₂ — include the following groups.

In an oxygen atom, one -CH ₂ - - 2 two -CH ₂ - contained in the ring W 'is the -SO ₂ - is ^{Y 1} substituted with, for example, include the following groups.

A is -O-, 1 single -CH ₂ - - 1 one -CH ₂ - contained in the ring W 'is is -CO-, 1 single -CH ₂ - is a ^{Y 1} substituted with, - is -SO ₂ For example, the following groups are mentioned.

Examples of Y ¹ in which one —CH ₂ — contained in the ring W ′ is substituted with —N (R ^c ) — include the following groups.

［式（Ｙ２）及び式（Ｙ３）中、
環に含まれる水素原子は、ハロゲン原子（フッ素原子を除く）、水酸基、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６〜１２のアリール基、炭素数７〜１２のアラルキル基、グリシジルオキシ基又は炭素数２〜４のアシル基で置換されていてもよく、環に含まれる−ＣＨ_２−は、−ＣＯ−、−Ｏ−、−Ｓ−又は−Ｎ（Ｒ^ｃ）−で置き換わっていてもよい。
Ｒ^ｃは、上記と同じ意味である。
＊は、Ｘ^１との結合手を表す。］ Among these, Y ¹ is more preferably a group represented by the formula (Y2) or the formula (Y3).

[In Formula (Y2) and Formula (Y3),
The hydrogen atom contained in the ring is a halogen atom (excluding a fluorine atom), a hydroxyl group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or 7 to 7 carbon atoms. 12 aralkyl group may be substituted with a glycidyloxy group or an acyl group having 2 to 4 carbon atoms, -CH ₂ contained in the ring - is, -CO -, - O -, - S- or -N ( R ^c ) — may be replaced.
R ^c has the same meaning as described above.
* Represents a bond to ^{X 1.} ]

  Examples of the anion of the salt represented by the formula (I) include the following formula (IA), formula (IB), formula (IC), formula (ID) and the like. Among these, anions represented by formula (IA) and formula (IB) are suitable.

［式（ＩＡ）、式（ＩＢ）、式（ＩＣ）及び式（ＩＤ）中、
Ｑ^１、Ｑ^２及びＹ^１は、式（Ｉ）における定義と同じである。
Ｘ¹⁰、Ｘ¹¹及びＸ¹²は、互いに独立に、単結合、直鎖状又は分岐状の炭素数１〜１６のアルキレン基を表す。］

[In formula (IA), formula (IB), formula (IC) and formula (ID),
Q ¹ , Q ² and Y ¹ are the same as defined in formula (I).
X ¹⁰ , X ¹¹ and X ¹² each independently represent a single bond, a linear or branched alkylene group having 1 to 16 carbon atoms. ]

In formula (IA), a hydrogen atom contained in ring W ′ is substituted only with a hydrocarbon group (—CH ₂ — contained in the hydrocarbon group may be substituted with an oxygen atom or the like) as an anion Examples include the following.

  In the formula (IA), examples of the anion in which the hydrogen atom contained in the ring W ′ is substituted with a hydroxyl group or a group containing a hydroxyl group (but not having a lactone structure) include the following.

In formula (IA), examples of the anion having a lactone structure in which two adjacent —CH ₂ — contained in the ring W ′ are substituted with an oxygen atom and a carbonyl group include the following.

In formula (IA), examples of the anion having a ketone structure in which —CH ₂ — contained in ring W ′ is substituted with a carbonyl group include the following.

  In formula (IA), examples of the anion in which the hydrogen atom contained in ring W ′ is substituted with an aromatic hydrocarbon group or a group having an aromatic ring include the following.

In the formula (IA), examples of the anion having an ether structure in which —CH ₂ — contained in the ring W ′ is substituted with an oxygen atom include the followings.

Furthermore, examples of the anion represented by the formula (IA) include the following.

In formula (IB), the hydrogen atom contained in ring W ′ is not substituted or substituted only with a hydrocarbon group (the —CH ₂ — contained in ring W ′ may be substituted with an oxygen atom or the like). Good) Examples of anions include the following.

  In formula (IB), examples of the anion in which the hydrogen atom contained in ring W ′ is substituted with a hydroxyl group or a group containing a hydroxyl group include the following.

Examples of the anion having a lactone structure in which two adjacent —CH ₂ — contained in the ring W ′ in the formula (IB) are substituted with an oxygen atom and a carbonyl group include the following.

In formula (IB), examples of the anion having a ketone structure in which one —CH ₂ — contained in ring W ′ is substituted with a carbonyl group include the following.

  In the formula (IB), examples of the anion in which the hydrogen atom contained in the ring W ′ is substituted with an aromatic hydrocarbon group include the following.

Furthermore, examples of the anion represented by the formula (IB) include the following.

In the formula (IC), the hydrogen atom contained in the ring W ′ is not substituted or substituted only with a hydrocarbon group (the —CH ₂ — contained in the ring W ′ may be substituted with an oxygen atom or the like). Good) Examples of anions include the following.

  In formula (IC), examples of the anion in which the hydrogen atom contained in ring W ′ is substituted with a hydroxyl group or a group containing a hydroxyl group include the following.

In formula (IC), examples of the anion having a ketone structure in which one —CH ₂ — contained in ring W ′ is substituted with a carbonyl group include the following.

Furthermore, examples of the anion represented by the formula (IC) include the following.

In the formula (ID), the hydrogen atom contained in the ring W ′ is not substituted or substituted only with a hydrocarbon group (the —CH ₂ — contained in the ring W ′ may be substituted with an oxygen atom or the like). Good) Examples of anions include the following.

  In formula (ID), examples of the anion in which the hydrogen atom contained in ring W ′ is substituted with a hydroxyl group or a group containing a hydroxyl group include the following.

In the formula (ID), examples of the anion having a ketone structure in which one —CH ₂ — contained in the ring W ′ is substituted with a carbonyl group include the following.

Furthermore, examples of the anion represented by the formula (ID) include the following.

Examples of Z ^{+ in the} salt represented by the formula (I) include cations such as the formula (IXz), the formula (IXb), the formula (IXc), and the formula (IXd).

［式（ＩＸｚ）中、
Ｐ^ａ、Ｐ^ｂ及びＰ^ｃは、互いに独立に、直鎖状又は分岐状の炭素数１〜３０のアルキル基、炭素数３〜３０の脂環式炭化水素基あるいは炭素数６〜２０の芳香族炭化水素基を表す。
Ｐ^ａ、Ｐ^ｂ及びＰ^ｃのいずれかがアルキル基である場合、該アルキル基は、水酸基、直鎖状又は分岐状の炭素数１〜１２のアルコキシ基あるいは炭素数３〜１２の環式炭化水素基で置換されていてもよく、
Ｐ^ａ、Ｐ^ｂ及びＰ^ｃのいずれかが脂環式炭化水素基又は芳香族炭化水素である場合には、水素原子、水酸基、ハロゲン原子、直鎖状又は分岐状の炭素数１〜１２のアルキル基、直鎖状又は分岐状の炭素数１〜１２のアルコキシ基あるいは炭素数４〜３６の脂環式炭化水素を表し、該脂環式炭化水素基に含まれる水素原子は、ハロゲン原子、水酸基、直鎖状又は分岐状の炭素数１〜１２のアルキル基、直鎖状又は分岐状の炭素数１〜１２のアルコキシ基、炭素数６〜１２のアリール基、炭素数７〜１２のアラルキル基、グリシジルオキシ基あるいは炭素数２〜４のアシル基で置換されていてもよい。
式（ＩＸｂ）中、Ｐ^４及びＰ^５は、互いに独立に、水素原子、水酸基、直鎖状又は分岐状の炭素数１〜１２のアルキル基あるいは炭素数１〜１２のアルコキシ基を表す。

[In the formula (IXz),
P ^a , P ^b and P ^c are each independently a linear or branched alkyl group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 30 carbon atoms or an aromatic group having 6 to 20 carbon atoms. Represents a group hydrocarbon group.
When any one of P ^a , P ^b and P ^c is an alkyl group, the alkyl group is a hydroxyl group, a linear or branched alkoxy group having 1 to 12 carbon atoms, or a cyclic carbonization having 3 to 12 carbon atoms. May be substituted with a hydrogen group,
When any of P ^a , P ^b and P ^c is an alicyclic hydrocarbon group or an aromatic hydrocarbon, a hydrogen atom, a hydroxyl group, a halogen atom, a linear or branched ^C 1-12 carbon atom Represents an alkyl group, a linear or branched alkoxy group having 1 to 12 carbon atoms or an alicyclic hydrocarbon having 4 to 36 carbon atoms, and the hydrogen atom contained in the alicyclic hydrocarbon group is a halogen atom, Hydroxyl group, linear or branched alkyl group having 1 to 12 carbon atoms, linear or branched alkoxy group having 1 to 12 carbon atoms, aryl group having 6 to 12 carbon atoms, aralkyl having 7 to 12 carbon atoms Group, a glycidyloxy group, or an acyl group having 2 to 4 carbon atoms.
In formula (IXb), P ⁴ and P ⁵ each independently represent a hydrogen atom, a hydroxyl group, a linear or branched alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.

In formula (IXc),
P ⁶ and P ⁷ each independently represent a linear or branched alkyl group having 1 to 12 carbon atoms or a cycloalkyl group having 3 to 12 carbon atoms, or P ⁶ and P ⁷ are combined together. A ring having 3 to 12 carbon atoms may be formed.
P ⁸ represents a hydrogen atom, and P ⁹ is a linear or branched alkyl group having 1 to 12 carbon atoms and a C 6 to 20 carbon atom that may be substituted with a cycloalkyl group having 3 to 12 carbon atoms. Or P ⁸ and P ⁹ may be combined to form a ring having 3 to 12 carbon atoms.

In formula (IXd),
P ¹⁰ to P ²¹ are independently of each other, represent a hydrogen atom, a hydroxyl group, an alkyl group or an alkoxy group having 1 to 12 carbon atoms having 1 to 12 carbon atoms.
E represents a sulfur atom or an oxygen atom.
m represents 0 or 1. ]

The alkyl group, alicyclic hydrocarbon group, aromatic hydrocarbon group, alkoxy group, cycloalkyl group and the like are the same as described above.
Examples of the cyclic hydrocarbon group include an alicyclic hydrocarbon group and an aromatic hydrocarbon group. Examples of the ring include a 3-membered ring to a 12-membered ring (preferably a 3-membered ring to a 7-membered ring). These rings —CH ₂ — may be replaced by —O—, —S— or —CO—. Specifically, a thiolane-1-ium ring (tetrahydrothiophenium ring), a thian-1-ium ring, a 1,4-oxathian-4-ium ring, an oxocycloheptane ring, an oxocyclohexane ring, an oxonorbornane ring, Examples thereof include an oxoadamantane ring.

  Among the cations represented by the formula (IXz), for example, a cation represented by the formula (IXa) is preferable.

［式（ＩＸａ）中、
Ｐ^１〜Ｐ^３は、互いに独立に、水素原子、水酸基、ハロゲン原子、直鎖状又は分岐状の炭素数１〜１２のアルキル基、直鎖状又は分岐状の炭素数１〜１２のアルコキシ基あるいは炭素数４〜３６の脂環式炭化水素を表し、該脂環式炭化水素基に含まれる水素原子は、ハロゲン原子、水酸基、直鎖状又は分岐状の炭素数１〜１２のアルキル基、直鎖状又は分岐状の炭素数１〜１２のアルコキシ基、炭素数６〜１２のアリール基、炭素数７〜１２のアラルキル基、グリシジルオキシ基あるいは炭素数２〜４のアシル基で置換されていてもよい。］

[In the formula (IXa)
P ^{1 to} P ³ are each independently a hydrogen atom, a hydroxyl group, a halogen atom, a linear or branched alkyl group having 1 to 12 carbon atoms, or a linear or branched alkoxy group having 1 to 12 carbon atoms. Alternatively, it represents an alicyclic hydrocarbon having 4 to 36 carbon atoms, and the hydrogen atom contained in the alicyclic hydrocarbon group is a halogen atom, a hydroxyl group, a linear or branched alkyl group having 1 to 12 carbon atoms, It is substituted with a linear or branched alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, a glycidyloxy group, or an acyl group having 2 to 4 carbon atoms. May be. ]

  In particular, those containing an adamantyl skeleton and an isobornyl skeleton are suitable as the alicyclic hydrocarbon group, preferably a 2-alkyl-2-adamantyl group, a 1- (1-adamantyl) -1-alkyl group, an isobornyl group, and the like. Is mentioned.

Examples of the cation represented by the formula (IXa) include the followings.

  Among the cations represented by the formula (IXa), the cation represented by the formula (IXe) is preferably used because of its easy production.

［式（ＩＸｅ）中、
Ｐ^２２、Ｐ^２３及びＰ^２４は、互いに独立に、水素原子、水酸基、ハロゲン原子、直鎖状又は分岐状の炭素数１〜１２のアルキル基あるいは直鎖状又は分岐状の炭素数１〜１２のアルコキシ基を表す。］

[In the formula (IXe)
P ²² , P ²³ and P ²⁴ are each independently a hydrogen atom, a hydroxyl group, a halogen atom, a linear or branched alkyl group having 1 to 12 carbon atoms, or a linear or branched carbon number 1 to 12. Represents an alkoxy group. ]

Examples of the cation represented by the formula (IXb) include the followings.

Examples of the cation represented by the formula (IXc) include the followings.

Examples of the cation represented by the formula (IXd) include the followings.

なかでも、Ｚ^＋は、アリールスルホニウムカチオンであるものが好ましい。

Among these, Z ⁺ is preferably an arylsulfonium cation.

The anions and cations described above can be arbitrarily combined.
For example, the salt represented by the formula (I) includes compounds represented by the formula (Xa) to the formula (Xo).

［式（Ｘａ）〜（Ｘｏ）中、
Ｐ^２５、Ｐ^２６及びＰ^２７は、互いに独立に、水素原子、直鎖状又は分岐状の炭素数１〜４の脂肪族炭化水素基あるいは炭素数４〜３６の脂環式炭化水素基を表す。
Ｐ^２８及びＰ^２９は、互いに独立に、直鎖状又は分岐状の炭素数１〜１２の脂肪族炭化水素基あるいは炭素数４〜３６の脂環式炭化水素基を表すか、あるいはＰ^２８とＰ^２９とが一緒になってＳ^＋を含んで炭素数２〜６の環を形成してもよい。
Ｐ^３０は、直鎖状又は分岐状の炭素数１〜１２の脂肪族炭化水素基、炭素数４〜３６の脂環式炭化水素基あるいは置換されていてもよい炭素数６〜２０の芳香族炭化水素基を表すか、あるいはＰ^３０とＰ^３１とが一緒になって炭素数３〜１２の環を形成してもよい。ここで、該環に含まれる−ＣＨ_２−は、任意に、−ＣＯ−、−Ｏ−、−Ｓ−、−ＳＯ_２−又は−Ｎ（Ｒ^ｃ）−で置き換わっていてもよい。
Ｑ^１、Ｑ^２及びＲ^ｃは、上記と同義である。
Ｘ^１３は、単結合または−ＣＨ_２−を表す。］

[In the formulas (Xa) to (Xo),
P ²⁵ , P ²⁶ and P ²⁷ each independently represent a hydrogen atom, a linear or branched aliphatic hydrocarbon group having 1 to 4 carbon atoms or an alicyclic hydrocarbon group having 4 to 36 carbon atoms. .
P ²⁸ and P ²⁹ each independently represent a linear or branched aliphatic hydrocarbon group having 1 to 12 carbon atoms or an alicyclic hydrocarbon group having 4 to 36 carbon atoms, or P ²⁸ and may form a ring of 2 to 6 carbon atoms include S ⁺ and P ²⁹ together.
P ³⁰ is a linear or branched aliphatic hydrocarbon group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 4 to 36 carbon atoms, or an optionally substituted aromatic group having 6 to 20 carbon atoms. It may represent a hydrocarbon group, or P ³⁰ and P ³¹ may form a ring having 3 to 12 carbon atoms together. Here, —CH ₂ — contained in the ring may be optionally replaced with —CO—, —O—, —S—, —SO ₂ — or —N (R ^c ) —.
Q ¹ , Q ² and R ^c are as defined above.
X ¹³ represents a single bond or —CH ₂ —. ]

Examples of the ring and P ²⁸ and P ²⁹ are formed together, such as tetrahydrothiophenium group.
Examples of the ring formed by combining P ³⁰ and P ³¹ include the groups of the above-described formulas (W13) to (W15).

Among the above combinations, the following salts can be mentioned.

  The salt represented by the formula (I) can be produced, for example, according to the method described in JP 2008-209917 A.

  In the resist composition of this invention, it is preferable that content of an acid generator (A) is 1-20 mass parts with respect to 100 mass parts of resin (B), Furthermore, it is 1-15 mass parts. Is more preferable.

  In the resist composition of the present invention, the salt represented by the formula (I), which is an acid generator, generates an acid upon exposure, and catalytically reacts with a group in the resin that is unstable to the acid. It is cleaved by action to make the resin soluble in an alkaline aqueous solution. Such a resist composition is suitable as a chemically amplified positive resist composition.

  In the resist composition of the present invention, as an acid generator, in addition to the salt represented by the formula (I), a photo-initiator for photocationic polymerization, a photoinitiator for photoradical polymerization, and photo-extinction of dyes. A known compound that generates an acid upon irradiation with actinic rays or radiation used for a colorant, a photochromic agent, a microresist, or the like and a mixture thereof may be appropriately selected and used.

Examples thereof include diazonium salts, phosphonium salts, sulfonium salts, iodonium salts, imide sulfonates, oxime sulfonates, diazodisulfones, disulfones, and o-nitrobenzyl sulfonates.
Examples of compounds in which a group or a compound that generates an acid upon irradiation with actinic rays or radiation is introduced into the main chain or side chain of the polymer include, for example, US Pat. No. 3,849,137 and German Patent No. 3914407. JP, 63-26653, JP, 55-164824, JP, 62-69263, JP, 63-146038, JP, 63-163452, JP, 62-153853, The compounds described in Japanese Utility Model Laid-Open No. 63-146029 can be used.
Further, compounds capable of generating an acid by light described in US Pat. No. 3,779,778, European Patent 126,712 and the like may be used.

［式（ａａ）中、
Ｔは、炭素数４〜３６の脂環式炭化水素基を表し、該脂環式炭化水素基に含まれる水素原子は、ハロゲン原子、水酸基、ハロゲン原子又は水酸基で置換されていてもよい炭素数１〜１２のアルキル基、炭素数１〜１２のアルコキシ基、炭素数６〜１２のアリール基、炭素数７〜１２のアラルキル基、グリシジルオキシ基、炭素数２〜４のアシル基、アルコキシカルボニル基、アルカノイルオキシアルキル基又はシアノ基で置換されていてもよく、該脂環式炭化水素基に含まれる−ＣＨ_２−は、少なくとも１つの−ＳＯ_２−で置き換わっており、さらに、−ＣＯ−、−Ｏ−、−Ｓ−、−ＳＯ_２−又は−Ｎ（Ｒ^ｃ）−で置き換わっていてもよい。
Ｒ^ｃは、水素原子又は炭素数１〜６のアルキル基を表す。
Ｒ^１は、水素原子、ハロゲン原子またはハロゲン原子を有してもよい炭素数１〜６のアルキル基を表す。］ The resin (B) has a repeating unit derived from the compound represented by the formula (aa).
<Resin having a repeating unit derived from the compound represented by the formula (aa)>

[In the formula (aa)
T represents an alicyclic hydrocarbon group having 4 to 36 carbon atoms, and the hydrogen atom contained in the alicyclic hydrocarbon group may be substituted with a halogen atom, a hydroxyl group, a halogen atom or a hydroxyl group. An alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, a glycidyloxy group, an acyl group having 2 to 4 carbon atoms, and an alkoxycarbonyl group , An alkanoyloxyalkyl group or a cyano group, and —CH ₂ — contained in the alicyclic hydrocarbon group is replaced by at least one —SO ₂ —, and —CO—, -O -, - S -, - SO 2 - or -N ^{(R c)} - it may be replaced by.
R ^c represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
R ¹ represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom. ]

Examples of the alkyl group which may be substituted with a halogen atom include a perfluoromethyl group, a perfluoroethyl group, a perfluoro-n-propyl group, a perfluoroisopropyl group, a perfluoro-n-butyl group, a perfluoro-sec-butyl group, and a perfluoro-tert. -Butyl group, perfluoro-n-pentyl group, perfluoro-n-hexyl group, perchloromethyl group, perchloroethyl group, perbromomethyl group, perbromoethyl group and the like can be mentioned.
Examples of the alkyl group which may be substituted with a hydroxyl group include a hydroxymethyl group and a 2-hydroxyethyl group.
Examples of the alkoxycarbonyl group include groups in which a carbonyl group is bonded to the aforementioned alkoxy group such as a methoxycarbonyl group and an ethoxycarbonyl group.
As the alkanoyloxyalkyl group, acetyloxymethyl group, propionyloxymethyl group, butyryloxymethyl group, acetyloxyethyl group, propionyloxyethyl group, butyryloxyethyl group, acetyloxypropyl group, propionyloxypropityl group, And a butyryloxypropytyl group.

In the compound represented by the formula (aa), R ¹ is preferably a hydrogen atom or a methyl group.
T is suitably a group represented by the formula (T0), and in particular, a group represented by the formula (T0a) is suitable.
Moreover, T is preferably a group represented by the formula (T1), and among them, a group represented by the formula (T1a) is preferable.
Further, T is more preferably a group represented by the formula (T2), and more preferably a group represented by the formula (T2a).

［式中、
環に含まれる水素原子は、ハロゲン原子、水酸基、ハロゲン原子又は水酸基で置換されていてもよい炭素数１〜１２のアルキル基、炭素数１〜１２のアルコキシ基、炭素数６〜１２のアリール基、炭素数７〜１２のアラルキル基、グリシジルオキシ基、炭素数２〜４のアシル基、アルコキシカルボニル基、アルカノイルオキシアルキル基又はシアノ基で置換されていてもよく、環に含まれる−ＣＨ_２−は、少なくとも１つの−ＳＯ_２−で置き換わっており、さらに、−ＣＯ−、−Ｏ−、−Ｓ−、−ＳＯ_２−又は−Ｎ（Ｒ^ｃ）−で置き換わっていてもよい。
Ｒ^ｃは、上記と同じ意味を表す。
＊は、酸素原子との結合手を表す。
Ｔ^１は、酸素原子又は−ＣＨ_２−を表す。］

[Where:
The hydrogen atom contained in the ring is a halogen atom, a hydroxyl group, an alkyl group having 1 to 12 carbon atoms which may be substituted with a halogen atom or a hydroxyl group, an alkoxy group having 1 to 12 carbon atoms, or an aryl group having 6 to 12 carbon atoms. , An aralkyl group having 7 to 12 carbon atoms, a glycidyloxy group, an acyl group having 2 to 4 carbon atoms, an alkoxycarbonyl group, an alkanoyloxyalkyl group or a cyano group, and —CH ₂ — contained in the ring Is replaced by at least one —SO ₂ —, and may be further replaced by —CO—, —O—, —S—, —SO ₂ — or —N (R ^c ) —.
R ^c represents the same meaning as described above.
* Represents a bond with an oxygen atom.
T ¹ represents an oxygen atom or —CH ₂ —. ]

Examples of T include the following. * Indicates a binding site with an oxygen atom.

  In addition to the groups exemplified above, as shown in the following compounds, a halogen atom, a hydroxyl group, an alkyl group having 1 to 12 carbon atoms which may be substituted with a halogen atom or a hydroxyl group, and alkoxy having 1 to 12 carbon atoms Group, aryl group having 6 to 12 carbon atoms, aralkyl group having 7 to 12 carbon atoms, glycidyloxy group, acyl group having 2 to 4 carbon atoms, alkoxycarbonyl group, alkanoyloxyalkyl group or cyano group Good.

Examples of the compound represented by the formula (aa) include the following compounds.

The compound represented by the formula (aa) described above can be produced by a method known in the art.
The content of the repeating unit derived from the compound represented by the formula (aa) in the resin is usually 2 to 40 mol%, preferably 3 to 35 mol%, more preferably 5 in all units of the resin. ˜30 mol%.

［式（ｂｂ）中、
Ｒ^１、Ｚ^２は、上記と同じ意味を表す。
Ｘは、−Ｏ−、−Ｓ−又は−ＣＨ_２−を表す。］ The resin (B) preferably further contains a repeating unit derived from a compound having a norbornane lactone structure in addition to the repeating unit derived from the compound represented by the formula (aa).
Examples of the compound having a norbornane lactone structure include a compound represented by the formula (bb).

[In the formula (bb),
R ¹ and Z ² represent the same meaning as described above.
X is, -O -, - S- or represents -CH ₂ -. ]

R ¹ is preferably a hydrogen atom or a methyl group.
Examples of the compound represented by the formula (bb) include the following compounds.

  The content of the repeating unit derived from the compound represented by the formula (bb) in the resin is usually 5 to 50 mol%, preferably 10 to 45 mol%, more preferably 15 in all units of the resin. -40 mol%.

The resin (B) preferably further contains a structural unit derived from a compound having an adamantyl group substituted with at least two hydroxyl groups.
Examples of the compound having an adamantyl group substituted with at least two hydroxyl groups include a compound represented by the formula (cc).

［式（ｃｃ）中、
Ｒ^１及びＺ^２は、上記と同じ意味を表す。
Ｒ^２及びＲ^３は、互いに独立に、水素原子、メチル基又は水酸基を表す。ただし、Ｒ^２及びＲ^３の少なくともいずれか一方は、水酸基を表す。
Ｒ^４は、炭素数１〜６のアルキル基を表す。
ｎは、０〜１０の整数を表す。］

[In the formula (cc),
R ¹ and Z ² represent the same meaning as described above.
R ² and R ³ each independently represent a hydrogen atom, a methyl group or a hydroxyl group. However, at least one of R ² and R ³ represents a hydroxyl group.
R ⁴ represents an alkyl group having 1 to 6 carbon atoms.
n represents an integer of 0 to 10. ]

R ¹ and R ⁴ are preferably a hydrogen atom or a methyl group.

Examples of the compound represented by the formula (cc) include the following compounds.

  The content of the repeating unit derived from the compound represented by the formula (cc) in the resin is usually 3 to 40 mol%, preferably 5 to 35 mol%, more preferably 5 in the total unit of the resin. ˜30 mol%.

The resin (B) preferably further has an acid labile group.
The resin (B) is a resin that is insoluble or hardly soluble in an aqueous alkali solution, and is preferably a resin that can be dissolved in an aqueous alkali solution by acting with an acid.

  A resin having an “acid-labile group” is one in which part or all of the hydrophilic group in the molecule is protected by a protecting group that can be removed by contact with an acid. Upon contact, the protecting group is removed and the resin is converted to a resin soluble in an aqueous alkali solution. Hereinafter, the hydrophilic group protected by the protecting group is referred to as “acid-labile group”. Examples of the hydrophilic group include a hydroxy group or a carboxy group, and a carboxy group is more preferable.

式（１）中、
Ｒ^ａ１、Ｒ^ａ２及びＲ^ａ３は、それぞれ独立に、炭素数１〜８の脂肪族炭化水素基又は炭素数３〜２０の脂環基を表すか、或いは、Ｒ^a1及びＲ^a2は互いに結合して、それらが結合する炭素原子とともに炭素数３〜２０の環を形成する。Ｒ^a1及びＲ^a2が互いに結合して形成される環、該脂肪族炭化水素基又は該脂環基がメチレン基を有する場合、それに含まれる−ＣＨ_２−は、−Ｏ−、−Ｓ−又は−ＣＯ−で置き換わっていてもよい。＊は結合手を表す。 When the hydrophilic group is a carboxy group, the acid labile group is such that the hydrogen atom of the carboxy group is replaced with an organic residue, and the atom of the organic residue bonded to the oxy group is a tertiary carbon atom. Groups. Among such acid labile groups, preferred acid labile groups are, for example, those represented by the following formula (1) (hereinafter sometimes referred to as “acid labile group (1)”) It is said.)

In formula (1),
R ^a1 , R ^a2 and R ^a3 each independently represent an aliphatic hydrocarbon group having 1 to 8 carbon atoms or an alicyclic group having 3 to 20 carbon atoms, or R ^a1 and R ^a2 are bonded to each other. Thus, a ring having 3 to 20 carbon atoms is formed together with the carbon atom to which they are bonded. When the ring formed by combining R ^a1 and R ^a2 , the aliphatic hydrocarbon group or the alicyclic group has a methylene group, —CH ₂ — contained therein is —O—, —S— or It may be replaced by -CO-. * Represents a bond.

この脂環基は、好ましくは炭素数が１〜１６である。 Examples of the aliphatic hydrocarbon group represented by R ^{a1 to} R ^a3 include alkyl groups such as 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 group of R ^{a1 to} R ^a3 may be monocyclic or polycyclic. Examples of the monocyclic alicyclic group include cycloalkyl groups such as a cyclopentyl group, a cyclohexyl group, a methylcyclohexyl group, a dimethylcyclohexyl group, a cycloheptyl group, and a cyclooctyl group. Examples of the polycyclic alicyclic group include a decahydronaphthyl group, an adamantyl group, a norbornyl group, a methylnorbornyl group, and groups shown below.

This alicyclic group preferably has 1 to 16 carbon atoms.

式（１）では、このような環の炭素数は、好ましくは３〜１２である。 When R ^a1 and R ^a2 are bonded to each other to form a ring, examples of the —C (R ^a1 ) (R ^a2 ) (R ^a3 ) group include the following groups.

In the formula (1), the number of carbon atoms in such a ring is preferably 3-12.

Specific examples of the acid labile group (1) are:
1,1-dialkylalkoxycarbonyl group (in formula (1), R ^{a1 to} R ^a3 are all alkyl groups, and one of these alkyl groups is preferably a tert-butoxycarbonyl group),
2-alkyl-2-adamantyloxycarbonyl group (in the formula (1), R ^a1 and R ^a2 are bonded to each other to form an adamantyl ring together with the carbon atom to which they are bonded, and R ^a3 is an alkyl group) and 1- (1-adamantyl) -1-alkylalkoxycarbonyl group (in the formula (1), R ^a1 and R ^a2 are alkyl groups, and R ^a3 is an adamantyl group).

The resin (B) can be produced by addition polymerization of a monomer having an acid labile group and an olefinic double bond.
Such monomers include bulky groups such as alicyclic structures such as 2-alkyl-2-adamantyl groups and 1- (1-adamantyl) -1-alkylalkyl groups as acid labile groups. Monomers are preferred because the resolution of the resulting resist tends to be excellent.

  Specific examples of the monomer containing a bulky group include 2-alkyl-2-adamantyl (meth) acrylate, 1- (1-adamantyl) -1-alkylalkyl (meth) acrylate, and 5-norbornene-2. -2-alkyl-2-adamantyl carboxylate, 1- (1-adamantyl) -1-alkylalkyl 5-norbornene-2-carboxylate, 2-alkyl-2-adamantyl α-chloroacrylate, α-chloroacrylic acid 1- (1-adamantyl) -1-alkylalkyl and the like.

  In particular, when 2-alkyl-2-adamantyl (meth) acrylate or 2-alkyl-2-adamantyl α-chloroacrylate is used as a monomer, it is preferable because the resolution of the resulting resist tends to be excellent.

  Specifically, as 2-alkyl-2-adamantyl (meth) acrylate, for example, 2-methyl-2-adamantyl acrylate, 2-methyl-2-adamantyl methacrylate, 2-ethyl-2-acrylate Examples include adamantyl, 2-ethyl-2-adamantyl methacrylate, 2-n-butyl-2-adamantyl acrylate, and the like. Examples of the α-chloro-2-alkyl-2-adamantyl α-chloroacrylate include 2-methyl-2-adamantyl α-chloroacrylate, 2-ethyl-2-adamantyl α-chloroacrylate, and the like.

  Among these, when 2-ethyl-2-adamantyl (meth) acrylate or 2-isopropyl-2-adamantyl (meth) acrylate is used, the resulting resist tends to have excellent sensitivity and heat resistance. preferable.

  (Meth) acrylic acid 2-alkyl-2-adamantyl can be usually produced by a reaction of 2-alkyl-2-adamantanol or a metal salt thereof with acrylic acid halide or methacrylic acid halide.

  Examples of the monomer having an acid labile group other than the above include monomers represented by the formula (g) having an acetal type labile group (2).

式（２）中、
Ｒ^b1及びＲ^b2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^b3は、炭素数１〜２０の炭化水素基を表すか、あるいは、Ｒ^b2及びＲ^b3は互いに結合して、それらが各々結合する炭素原子及び酸素原子とともに炭素数３〜２０の環を形成する。Ｒ^b2及びＲ^b3は互いに結合して形成される環又は該炭化水素基メチレン基を有する場合、それに含まれる−ＣＨ_２−は、−Ｏ−、−Ｓ−又は−ＣＯ−で置き換わっていてもよい。＊は結合手を表す。 In the case where the hydrophilic group is a hydroxy group, examples of the acid labile group include those in which the hydrogen atom of the hydroxy group is replaced with an organic residue to become a group containing an acetal structure. Among such acid labile groups, preferred acid labile groups are, for example, those represented by the following formula (2) (hereinafter referred to as “acid labile group (2)” in some cases. ).

In formula (2),
R ^b1 and R ^b2 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, R ^b3 represents a hydrocarbon group having 1 to 20 carbon atoms, or R ^b2 and R ^b3 Are bonded to each other to form a ring having 3 to 20 carbon atoms together with the carbon atom and the oxygen atom to which they are bonded. When R ^b2 and R ^b3 have a ring formed by bonding to each other or the hydrocarbon group methylene group, —CH ₂ — contained therein may be replaced by —O—, —S— or —CO—. Good. * Represents a bond.

Examples of the hydrocarbon group of R ^{b1 to} R ^b3 include an aliphatic hydrocarbon group, an alicyclic group, and an aromatic hydrocarbon group. Here, the aliphatic hydrocarbon group and the alicyclic group are the same as those described as the groups R ^{a1 to} R ^a3 . Examples of the aromatic hydrocarbon group include phenyl group, naphthyl group, anthranyl group, p-methylphenyl group, p-tert-butylphenyl group, p-adamantylphenyl group, tolyl group, xylyl group, cumenyl group, mesityl group, Examples thereof include aryl groups such as biphenyl group, anthryl group, phenanthryl group, 2,6-diethylphenyl group, and 2-methyl-6-ethylphenyl.
At least one of R ^{b1 to} R ^b2 is preferably a hydrogen atom.

Examples of the acid labile group (2) include the following groups.

［式（ｇ）中、Ｒ^10aは、水素原子、ハロゲン原子又はハロゲン原子を有してもよい炭素数１〜６のアルキル基を表す。
Ｒ^11aは、それぞれ独立に、ハロゲン原子、水酸基、炭素数１〜６のアルキル基、炭素数１〜６のアルコキシ基、炭素数２〜４のアシル基、炭素数２〜４のアシルオキシ基、アクリロイル基又はメタクリロイル基を表す。
ｌ^ａは０〜４の整数を表す。ｌ^ａが２以上の整数である場合、複数のＲ^11aは同一の種類の基であっても異なる種類の基であってもよい。
Ｒ^12a及びＲ^13aはそれぞれ独立に、水素原子又は炭素数１〜１２の炭化水素基を表す。
Ｘ^ａ２は、単結合又は置換基を有していてもよい炭素数１〜１７の飽和炭化水素基を表し、該飽和炭化水素基に含まれる−ＣＨ_２−は−ＣＯ−、−Ｏ−、−Ｓ−、−ＳＯ_２−又は−Ｎ（Ｒ^ｃ）−で置き換わっていてもよい。
Ｒ^ｃは、水素原子又は炭素数１〜６のアルキル基を表す。
Ｙ^ａ３は、炭素数１〜１２の脂肪族炭化水素基、炭素数３〜１８の飽和環状炭化水素基又は炭素数６〜１８の芳香族炭化水素基であり、該脂肪族炭化水素基、飽和環状炭化水素基及び芳香族炭化水素基は、置換基を有していてもよい。］ The monomers represented by the formula (g) are as follows.

[In Formula (g), R ^<10a > represents a C1-C6 alkyl group which may have a hydrogen atom, a halogen atom, or a halogen atom.
R ^11a is independently a halogen atom, a hydroxyl 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, or acryloyl. Represents a group or a methacryloyl group.
l ^a represents an integer of 0 to 4; If l ^a is an integer of 2 or more, plural R ^11a may be the same kind a group even if different types of groups.
R ^12a and R ^13a each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms.
X ^a2 represents a C1-C17 saturated hydrocarbon group which may have a single bond or a substituent, and —CH ₂ — contained in the saturated hydrocarbon group is —CO—, —O—, -S -, - SO ₂ - or -N ^{(R c)} - may be replaced by.
R ^c represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
Y ^a3 is an aliphatic hydrocarbon group having 1 to 12 carbon atoms, a saturated cyclic hydrocarbon group having 3 to 18 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms, and the aliphatic hydrocarbon group, saturated The cyclic hydrocarbon group and the aromatic hydrocarbon group may have a substituent. ]

Examples of the acyloxy group include acetyloxy, propionyloxy, butyryloxy and the like.
Examples of the hydrocarbon group include an aliphatic hydrocarbon, an alicyclic hydrocarbon, an aromatic hydrocarbon, or a group obtained by combining these. Among them, methyl groups, ethyl groups, n-propyl groups, isopropyl groups, n-butyl groups, sec-butyl groups, tert-butyl groups, pentyl groups, hexyl groups, octyl groups, 2-ethylhexyl groups and other alkyl groups, An alicyclic hydrocarbon such as a cyclohexyl group, adamantyl group, 2-alkyl-2-adamantyl group, 1- (1-adamantyl) -1-alkyl group, and isobornyl group is preferred.
The saturated cyclic hydrocarbon group may be monocyclic or polycyclic.
The monocyclic saturated cyclic hydrocarbon group includes a cycloalkyl group (for example, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, methylcyclohexyl group, dimethylcyclohexyl group, cycloheptyl group, methylcycloheptyl group). Group, cyclooctyl group, cyclononyl group, cyclodecyl group), cycloalkenyl group (for example, cyclopentenyl group, cyclohexenyl group, cycloheptenyl group, cyclooctenyl group) and the like.
Examples of the polycyclic saturated cyclic hydrocarbon group include a group obtained by hydrogenating a condensed aromatic hydrocarbon group (for example, hydronaphthyl group), a bridged cyclic hydrocarbon group (for example, 1-adamantyl group, 2-adamantyl group). Group, norbornyl group, methylnorbornyl, isobornyl group) and the like. Further, a bridged ring (for example, norbornane ring) and a monocyclic (for example, cycloheptane ring or cyclohexane ring) or polycyclic (for example, decahydronaphthalene ring) group or a group in which bridged rings are condensed Are also included in the saturated cyclic hydrocarbon group.

Examples of the substituent for Y ^a3 include a halogen atom, a hydroxyl group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, A glycidyloxy group, a C2-C4 acyl group, a cyano group, etc. are mentioned.
In the monomer (g), the alkyl group and the alkoxy group are preferably groups having 1 to 4 carbon atoms, more preferably groups having 1 to 2 carbon atoms, and even more preferably groups having 1 carbon atom.

Examples of the monomer (g) include the following monomers.

  The content of the repeating unit derived from the monomer having an acid labile group in the resin is usually 10 to 95 mol%, preferably 15 to 90 mol%, more preferably 20 in all units of the resin. -85 mol%.

  Resin (B) is derived from an acid-stable monomer in addition to a repeating unit derived from the compound represented by formula (aa) and a repeating unit derived from a monomer having an acid-labile group. Repeating units may be included. Here, the structure derived from an acid-stable monomer means a structure that is not cleaved by an acid generator.

The content of the repeating unit derived from the monomer having an acid-stable group in the resin is usually from 5 to 90 mol%, preferably from 10 to 85 mol%, more preferably from 15 to 15 mol% in all the units of the resin. 80 mol%.
Specifically, a repeating unit derived from a monomer having a free carboxylic acid group such as acrylic acid or methacrylic acid, a repeating unit derived from an aliphatic unsaturated dicarboxylic anhydride such as maleic anhydride or itaconic anhydride , A repeating unit derived from 2-norbornene, a repeating unit derived from (meth) acrylonitrile, an alkyl ester or 1-adamantyl ester in which the carbon atom adjacent to the oxygen atom is a secondary or tertiary carbon atom (meth) Derived from a repeating unit derived from an acrylate ester, a repeating unit derived from a styrene monomer such as p- or m-hydroxystyrene, and a (meth) acryloyloxy-γ-butyrolactone in which the lactone ring may be substituted with an alkyl group And the like. In the 1-adamantyl ester, the carbon atom adjacent to the oxygen atom is a quaternary carbon atom. However, the 1-adamantyl ester is an acid-stable group, and a hydroxyl group or the like may be bonded to the 1-adamantyl ester.

  Acid stable monomers include 3-hydroxy-1-adamantyl (meth) acrylate, 3,5-dihydroxy-1-adamantyl (meth) acrylate, α- (meth) acryloyloxy-γ-butyrolactone, β- ( (Meth) acryloyloxy-γ-butyrolactone, a monomer that gives a repeating unit represented by formula (a), a monomer that gives a repeating unit represented by formula (b), hydroxystyrene, norbornene, etc., and has an olefinic double bond in the molecule Examples include alicyclic compounds, aliphatic unsaturated dicarboxylic anhydrides such as maleic anhydride, itaconic anhydride, and the like.

  Among these, in particular, a repeating unit derived from a styrene monomer such as p- or m-hydroxystyrene, a repeating unit derived from 3-hydroxy-1-adamantyl (meth) acrylate, and (meth) acrylic acid 3,5 Obtained from a resin containing any one of a repeating unit derived from -dihydroxy-1-adamantyl, a repeating unit represented by formula (a), a repeating unit represented by formula (b1), and a repeating unit represented by formula (b2) The resist is preferable because the adhesion to the substrate and the resolution of the resist tend to be improved.

（式中、
Ｌ^１〜Ｌ^３は、それぞれ独立に、酸素原子、カルボニル基、−Ｎ（Ｒ^ｃ）−、直鎖又は分枝の炭素数１〜１７のアルカンジイル基又はこれらの組合せを表し、
Ｒ^ｃは、水素原子又は炭素数１〜６の脂肪族炭化水素を表す。
Ｒ^２〜Ｒ^４は、それぞれ独立に、水素原子又はメチル基を表す。
Ｒ^５は、炭素数１〜４の脂肪族炭化水素基を表し、
Ｒ^５は、水素原子、直鎖又は分枝の炭素数１〜６の脂肪族炭化水素基を表す。
Ｒ^６及びＲ^７は、それぞれ独立に、カルボキシ基、シアノ基又は炭素数１〜４の脂肪族炭化水素基を表し、
ｑは０〜５の整数を表す。
ｓ及びｔは、それぞれ独立に０〜３の整数を表す。
ｑ、ｓ及びｔが２以上のとき、それぞれ、複数のＲ^５、Ｒ^６及びＲ^７は、互いに同一でも異なってもよい。）

(Where
L ^{1 to} L ³ each independently represents an oxygen atom, a carbonyl group, —N (R ^c ) —, a linear or branched alkanediyl group having 1 to 17 carbon atoms, or a combination thereof,
R ^c represents a hydrogen atom or an aliphatic hydrocarbon having 1 to 6 carbon atoms.
R ^{2 to} R ⁴ each independently represent a hydrogen atom or a methyl group.
R ⁵ represents an aliphatic hydrocarbon group having 1 to 4 carbon atoms,
R ⁵ represents a hydrogen atom, a linear or branched aliphatic hydrocarbon group having 1 to 6 carbon atoms.
R ⁶ and R ⁷ each independently represent a carboxy group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms,
q represents an integer of 0 to 5.
s and t each independently represent an integer of 0 to 3.
When q, s, and t are 2 or more, the plurality of R ⁵ , R ^6, and R ⁷ may be the same or different from each other. )

Here, as the linear alkanediyl group, 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- A diyl group, a heptadecane-1,17-diyl group, etc. are mentioned.
Examples of the branched alkanediyl group include a linear alkanediyl group, a C _1-4 alkyl group (for example, methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec-butyl group, tert-butyl group, etc. For example, 1-methyl-1,3-propylene group, 2-methyl-1,3-propylene group, 2-methyl-1,2-propylene group, 1-methyl-1, 4-butylene group, 2-methyl-1,4-butylene group and the like can be mentioned.

  Monomers such as (meth) acrylic acid 3-hydroxy-1-adamantyl and (meth) acrylic acid 3,5-dihydroxy-1-adamantyl are commercially available. For example, it can also be produced by reacting the corresponding hydroxyadamantane with (meth) acrylic acid or its halide.

  In addition, a monomer such as (meth) acryloyloxy-γ-butyrolactone is obtained by reacting α- or β-bromo-γ-butyrolactone, which may have a lactone ring substituted with an alkyl group, with acrylic acid or methacrylic acid, or a lactone ring. Can be produced by reacting an α- or β-hydroxy-γ-butyrolactone optionally substituted with an alkyl group with an acrylic acid halide or methacrylic acid halide.

  Examples of the monomer that gives the repeating unit represented by the formulas (b1) and (b2) include (meth) acrylic acid esters of alicyclic lactones having the following hydroxyl groups, and mixtures thereof. These esters can be produced, for example, by a reaction between a corresponding alicyclic lactone having a hydroxyl group and (meth) acrylic acid (see, for example, JP-A No. 2000-26446).

  Here, as (meth) acryloyloxy-γ-butyrolactone, for example, α-acryloyloxy-γ-butyrolactone, α-methacryloyloxy-γ-butyrolactone, α-acryloyloxy-β, β-dimethyl-γ-butyrolactone, α- Methacryloyloxy-β, β-dimethyl-γ-butyrolactone, α-acryloyloxy-α-methyl-γ-butyrolactone, α-methacryloyloxy-α-methyl-γ-butyrolactone, β-acryloyloxy-γ-butyrolactone, β- Examples include methacryloyloxy-γ-butyrolactone, β-methacryloyloxy-α-methyl-γ-butyrolactone, and the like.

  The content of the repeating unit represented by the formula (a), the repeating unit represented by the formula (b1), and the repeating unit represented by the formula (b2) in the resin is usually 5 to 50 mol% in the total units of the resin. , Preferably it is 10-45 mol%, More preferably, it is 15-40 mol%.

In the case of KrF excimer laser exposure and EUV exposure, sufficient transmittance can be obtained even when a repeating unit derived from a styrene monomer such as p- or m-hydroxystyrene is used as the resin repeating unit. Such a copolymer resin can be obtained by radically polymerizing the corresponding (meth) acrylic acid ester monomer, acetoxystyrene, and styrene and then deacetylating with an acid.
Examples of the monomer that gives a repeating unit derived from a styrene monomer include the following compounds.

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

  The content of the repeating unit derived from the styrenic monomer in the resin is usually from 5 to 90 mol%, preferably from 10 to 85 mol%, more preferably from 15 to 80 mol%, in all units of the resin. .

  Moreover, since the resin containing a repeating unit derived from 2-norbornene has an alicyclic skeleton directly in its main chain, it has a strong structure and exhibits excellent dry etching resistance. The repeating unit derived from 2-norbornene can be introduced into the main chain by radical polymerization using, in addition to the corresponding 2-norbornene, an aliphatic unsaturated dicarboxylic acid anhydride such as maleic anhydride or itaconic anhydride. Therefore, the one formed by opening the double bond of the norbornene structure can be represented by the formula (c), and the one formed by opening the double bond of maleic anhydride and itaconic anhydride is respectively It can represent with Formula (d) and Formula (e).

ここで、式（ｃ）中のＲ⁵及びＲ⁶は、互いに独立に、水素原子、炭素数１〜３のアルキル基、カルボキシル基、シアノ基もしくは−ＣＯＯＵ（Ｕはアルコール残基である）を表すか、あるいは、Ｒ⁵及びＲ⁶が結合して、−Ｃ（＝Ｏ）ＯＣ（＝Ｏ）−で示されるカルボン酸無水物残基を表す。
Ｒ⁵及びＲ⁶が基−ＣＯＯＵである場合は、カルボキシル基がエステル基となったものであり、Ｕに相当するアルコール残基としては、例えば、置換されていてもよい炭素数１〜８程度のアルキル基、２−オキソオキソラン−３−又は−４−イル基などを挙げることができる。ここで、該アルキル基は、水酸基や脂環式炭化水素残基などが置換基として結合していてもよい。
Ｒ⁵及びＲ⁶がアルキル基である場合の具体例としては、メチル基、エチル基、プロピル基などが挙げられ、水酸基が結合したアルキル基の具体例としては、ヒドロキシメチル基、２−ヒドロキシエチル基などが挙げられる。

Here, R ⁵ and R ⁶ in formula (c) are each independently a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, a carboxyl group, a cyano group, or —COOU (U is an alcohol residue). Or R ⁵ and R ⁶ are bonded to each other to represent a carboxylic anhydride residue represented by —C (═O) OC (═O) —.
When R ⁵ and R ⁶ are a group —COOU, the carboxyl group is an ester group, and the alcohol residue corresponding to U has, for example, about 1 to 8 carbon atoms that may be substituted. And an alkyl group, a 2-oxooxolan-3- or -4-yl group. Here, in the alkyl group, a hydroxyl group, an alicyclic hydrocarbon residue, or the like may be bonded as a substituent.
Specific examples when R ⁵ and R ⁶ are alkyl groups include a methyl group, an ethyl group, and a propyl group. Specific examples of the alkyl group to which a hydroxyl group is bonded include a hydroxymethyl group and 2-hydroxyethyl group. Group and the like.

Thus, specific examples of the norbornene structure represented by the formula (c), which is a monomer that gives a stable repeating unit to an acid, include the following compounds.
2-norbornene,
2-hydroxy-5-norbornene,
5-norbornene-2-carboxylic acid,
Methyl 5-norbornene-2-carboxylate,
2-hydroxy-1-ethyl 5-norbornene-2-carboxylate,
5-norbornene-2-methanol,
5-norbornene-2,3-dicarboxylic anhydride.

In addition, in U of —COOU of R ⁵ and R ^{6 in} the formula (c), if it is an acid-labile group such as an alicyclic ester in which the carbon atom adjacent to the oxygen atom is a quaternary carbon atom, Even though it has a norbornene structure, it is a repeating unit having an acid labile group. Examples of the monomer containing a norbornene structure and an acid labile group include, for example, 5-norbornene-2-carboxylic acid-t-butyl, 5-norbornene-2-carboxylic acid 1-cyclohexyl-1-methylethyl, and 5-norbornene. 2-carboxylate 1-methylcyclohexyl, 5-norbornene-2-carboxylic acid 2-methyl-2-adamantyl, 5-norbornene-2-carboxylic acid 2-ethyl-2-adamantyl, 5-norbornene-2-carboxylic acid 1- (4-methylcyclohexyl) -1-methylethyl, 5-norbornene-2-carboxylic acid 1- (4-hydroxycyclohexyl) -1-methylethyl, 5-norbornene-2-carboxylic acid 1-methyl-1- (4-Oxocyclohexyl) ethyl, 5-norbornene-2-carboxylic acid 1- (1-adama) Chill) -1-methylethyl and the like.

  The content of the repeating unit represented by the formula (c), (d) or (e) in the resin is usually 2 to 40 mol%, preferably 3 to 30 mol%, in all units of the resin. More preferably, it is 5-20 mol%.

  Furthermore, you may contain the repeating unit containing a repeating unit represented by a formula (dd), and a fluorine atom as an acid stable group.

[In the formula (dd),
R ⁹ represents a hydrogen atom, a methyl group or a trifluoromethyl group.
AR represents a linear, branched or cyclic hydrocarbon group having 1 to 30 carbon atoms, and at least one hydrogen atom contained in the hydrocarbon group is substituted with a fluorine atom. —CH ₂ — contained in the hydrocarbon group may be substituted with —O—, —S— or —N (R ^c ) —, and the hydrogen atom contained in the hydrocarbon group may be a hydroxyl group or a straight It may be substituted with a chain or branched aliphatic hydrocarbon group having 1 to 6 carbon atoms. R ^c represents the same meaning as described above. ]

  Specific examples of the monomer that gives the repeating unit represented by the formula (dd) include the following monomers.

  The content of the repeating unit represented by the formula (dd) in the resin is usually 1 to 30 mol%, preferably 2 to 20 mol%, and more preferably in all units of the resin.

  In particular, as a repeating unit derived from a monomer having an acid labile group, 2-alkyl-2-adamantyl methacrylate, 2-alkyl-2-adamantyl acrylate 1- (1-adamantyl) -1- In the case of containing a repeating unit derived from alkylalkyl, 2-alkyl-2-adamantyl methacrylate 1- (1-adamantyl) -1-alkylalkyl acrylate, among the repeating units constituting the resin, the repeating unit If it is 15 mol% or more, the resin has an alicyclic group, so that it has a sturdy structure, which is advantageous in terms of dry etching resistance of the resist to be provided.

  In addition, when using an alicyclic compound having an olefinic double bond in the molecule and an aliphatic unsaturated dicarboxylic acid anhydride as monomers, these tend to be difficult to undergo addition polymerization. These are preferably used in excess.

  Further, as the monomer used, monomers having the same olefinic double bond but different acid labile groups may be used in combination, or monomers having the same acid labile group but different olefinic double bonds may be used. You may use together, and you may use together the monomer from which the combination of an acid labile group and an olefinic double bond differs.

  The weight average molecular weight of the resin (B) is preferably 2,500 or more and 100,000 or less, more preferably 2,700 or more and 50,000 or less, and further preferably 3,000 or more and 40,000 or less. .

  When the above-mentioned composition containing the acid generator (A) and the resin (B) is used as a resist composition, it contains a basic compound, preferably a basic nitrogen-containing organic compound, particularly preferably an amine or ammonium salt. Let By adding a basic compound as a quencher, it is possible to improve the performance degradation due to the deactivation of the acid accompanying the holding after exposure. Specific examples of the basic compound used for the quencher include those represented by the following formulas.

In the formula, R ¹¹ , R ¹² , R ¹⁷ , R ¹⁸ and R ¹⁹ are each independently a hydrogen atom, an aliphatic hydrocarbon group having 1 to 6 carbon atoms, or an alicyclic hydrocarbon group having 5 to 10 carbon atoms. Alternatively, it represents an aromatic hydrocarbon group having 6 to 20 carbon atoms. The hydrogen atom of the aliphatic hydrocarbon group, the hydrogen atom of the alicyclic hydrocarbon group, and the hydrogen atom of the aromatic hydrocarbon group may be substituted with a hydroxyl group, an amino group, or an alkoxy group having 1 to 6 carbon atoms. Good. The hydrogen atom of the amino group may be substituted with an aliphatic hydrocarbon group having 1 to 4 carbon atoms.

R ^{13 to} R ¹⁵ are each independently a hydrogen atom, a linear or branched aliphatic hydrocarbon group having 1 to 6 carbon atoms, a linear or branched alkoxy group having 1 to 6 carbon atoms, carbon It represents an alicyclic hydrocarbon group having 5 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 20 carbon atoms or a nitro group. The hydrogen atom of the aliphatic hydrocarbon group, the hydrogen atom of the alicyclic hydrocarbon group, the hydrogen atom of the aromatic hydrocarbon group and the hydrogen atom of the alkoxy group are independently of each other a hydroxyl group, an amino group or a straight chain. Or a branched or branched alkoxy group having 1 to 6 carbon atoms. The hydrogen atom of the amino group may be substituted with a linear or branched aliphatic hydrocarbon group having 1 to 4 carbon atoms. Alternatively, R ¹³ and R ¹⁴ may be bonded to form an aromatic ring.

R ¹⁶ and R ²⁰ represent a linear or branched aliphatic hydrocarbon group having 1 to 6 carbon atoms or an alicyclic hydrocarbon group having 5 to 10 carbon atoms. The hydrogen atom of the aliphatic hydrocarbon group or the hydrogen atom of the alicyclic hydrocarbon group is independently substituted with a hydroxyl group, an amino group, or a linear or branched alkoxy group having 1 to 6 carbon atoms. May be. The hydrogen atom of the amino group may be substituted with a linear or branched aliphatic hydrocarbon group having 1 to 4 carbon atoms.

  W represents an alkylene group having 2 to 6 carbon atoms, a carbonyl group, an imino group, a sulfanediyl group, or a disulfanediyl group.

  Examples of the aromatic ring include those similar to the aromatic hydrocarbon described above.

  Specific examples of such compounds include hexylamine, heptylamine, octylamine, nonylamine, decylamine, aniline, 2-, 3- or 4-methylaniline, 4-nitroaniline, diisopropylaniline, 1- or 2- Naphthylamine, ethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4′-diamino-1,2-diphenylethane, 4,4′-diamino-3,3′-dimethyldiphenylmethane, 4,4′-diamino-3, 3'-diethyldiphenylmethane, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, N-methylaniline, piperidine, diphenylamine, triethylamine, trimethylamine, tripro Ruamine, tributylamine, tripentylamine, trihexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, methyldibutylamine, methyldipentylamine, methyldihexylamine, methyldicyclohexylamine, methyldiheptylamine, Methyldioctylamine, methyldinonylamine, methyldidecylamine, ethyldibutylamine, ethyldipentylamine, ethyldihexylamine, ethyldiheptylamine, ethyldioctylamine, ethyldinonylamine, ethyldidecylamine, dicyclohexylmethylamine, tris [2- (2-methoxyethoxy) ethyl] amine, triisopropanolamine, N, N-dimethylaniline, 2,6-diisopropylaniline Imidazole, pyridine, 4-methylpyridine, 4-methylimidazole, bipyridine, 2,2′-dipyridylamine, di-2-pyridyl ketone, 1,2-di (2-pyridyl) ethane, 1,2-di (4 -Pyridyl) ethane, 1,3-di (4-pyridyl) propane, 1,2-bis (2-pyridyl) ethylene, 1,2-bis (4-pyridyl) ethylene, 1,2-bis (4-pyridyl) Oxy) ethane, 4,4′-dipyridyl sulfide, 4,4′-dipyridyl disulfide, 1,2-bis (4-pyridyl) ethylene, 2,2′-dipiconylamine, 3,3′-dipiconylamine, Tetramethylammonium hydroxide, tetraisopropylammonium hydroxide, tetrabutylammonium hydroxide, tetra-n-hexylammonium Examples thereof include hydroxide, tetra-n-octylammonium hydroxide, phenyltrimethylammonium hydroxide, 3-trifluoromethylphenyltrimethylammonium hydroxide, (2-hydroxyethyl) trimethylammonium hydroxide (common name: choline), and the like. . Of these, the basic compound is preferably diisopropylaniline.

  Furthermore, a hindered amine compound having a piperidine skeleton as disclosed in JP-A-11-52575 can be used as a quencher.

The resist composition of the present invention preferably contains the resin in the range of about 80 to 99.9% by weight and the acid generator in the range of about 0.1 to 20% by weight based on the total solid content.
Further, when a basic compound that is a quencher is used as the chemically amplified resist composition, it is preferably contained in a range of about 0.01 to 1% by weight based on the total solid content of the resist composition.
The resist composition can further contain small amounts of various additives such as sensitizers, dissolution inhibitors, other resins, surfactants, stabilizers, and dyes as necessary.

  The resist composition of the present invention is usually used as a resist solution composition in a state in which each of the above components is dissolved in a solvent, and is usually used in industrial processes such as spin coating on a substrate such as a silicon wafer. Applied by. The solvent used here may be any solvent that dissolves each component, has an appropriate drying rate, and gives a uniform and smooth coating film after the solvent evaporates, and is usually used industrially in this field. A solvent can be used.

  For example, 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, esters such as ethyl lactate, butyl acetate, amyl acetate and ethyl pyruvate And ketones such as acetone, methyl isobutyl ketone, 2-heptanone and cyclohexanone, and cyclic esters such as γ-butyrolactone. These solvents can be used alone or in combination of two or more.

The pattern forming method of the present invention comprises:
(1) An acid generator (A) containing, as an active ingredient, a resist composition containing a resin (B) having a repeating unit derived from the compound represented by formula (aa) or a salt represented by formula (I) A step of applying a resist composition containing
(2) a step of removing the solvent from the composition after coating to form a composition layer;
(3) a step of exposing the composition layer using an exposure machine (or an immersion exposure machine);
(4) A step of heating the composition layer after exposure,
(5) The process which develops the composition layer after a heating using a image development apparatus is included.

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

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

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

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

  The resist composition of the present invention is particularly useful for a chemically amplified photoresist composition, and is used in a wide range of applications such as semiconductor microfabrication, production of circuit boards such as liquid crystal and thermal head, and other photofabrication processes. Can be suitably used. In particular, since it has a good shape and excellent DOF, it can be used as a chemically amplified photoresist composition suitable for excimer laser lithography such as ArF and KrF, ArF immersion exposure lithography, and EUV exposure lithography. In addition to immersion exposure, it can also be used for dry exposure. Furthermore, it can be used for double imaging and is industrially useful.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these.
In Examples and Comparative Examples, “%” and “part” representing content and use amount are based on mass unless otherwise specified.

The weight average molecular weight is a value obtained by gel permeation chromatography (HLC-8120GPC type, manufactured by Tosoh Corporation, column: “TSKgel Multipore HXL-M”, 3 eluents: tetrahydrofuran) using polystyrene as a standard product. .
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 NMR (GX-270 type or EX-270 type manufactured by JEOL Ltd.) and mass spectrometry (LC: Agilent 1100 type, MASS: Agilent LC / MSD type or LC / MSD TOF type).

[Synthesis of Acid Generator A1]
To 100 parts of difluoro (fluorosulfonyl) acetic acid methyl ester and 150 parts of ion-exchanged water, 230 parts of a 30% aqueous sodium hydroxide solution was added dropwise in an ice bath. The mixture was refluxed at 100 ° C. for 3 hours, cooled, and neutralized with 88 parts of concentrated hydrochloric acid. The obtained solution was concentrated to obtain 164.4 parts of difluorosulfoacetate sodium salt (containing inorganic salt, purity 62.7%). To 1.9 parts of the obtained difluorosulfoacetic acid sodium salt (purity 62.7%) and 9.5 parts of N, N-dimethylformamide, 1.0 part of 1,1′-carbonyldiimidazole was added and added for 2 hours. Stir. To this solution, 0.2 parts of sodium hydride was added to 1.1 parts of 3-hydroxyadamantyl methanol and 5.5 parts of N, N-dimethylformamide, and the mixture was added to the solution stirred for 2 hours. After stirring for 15 hours, the resulting difluorosulfoacetic acid-3-hydroxy-1-adamantylmethyl ester sodium salt was used as such for the next reaction.

  To the obtained difluorosulfoacetate-3-hydroxy-1-adamantylmethyl ester sodium salt solution, 17.2 parts of chloroform and 2.9 parts of 14.8% aqueous triphenylsulfonium chloride were added. After stirring for 15 hours, the mixture was separated, and the aqueous layer was extracted with 6.5 parts of chloroform. The organic layers were combined and washed with ion exchange water, and the resulting organic layer was concentrated. Triphenylsulfonium 1-((3-hydroxyadamantyl) methoxycarbonyl) difluoromethanesulfonate (A1) 0.2 was added as a white solid by adding 5.0 parts of tert-butyl methyl ether to the concentrate, stirring and filtering. Got a part.

化合物（ａａ−１−ｂ）３０.００部、モノクロロベンゼン１２０．００部及び化合物（ａａ−１−ａ）１６.００部を仕込み、攪拌下、２３℃で硫酸１.４０部を仕込み、１２５℃に昇温、濃縮した。得られた反応物に、モレキュラーシーブ（４Ａ 和光純薬）４．００部を添加し、１２５℃で８時間還流脱水し、濃縮した。得られた濃縮物に、クロロホルム１６６部及びイオン交換水８３部を添加して洗浄し、分液して有機層を回収した。この水洗を計６回行った。回収された有機層に、活性炭１．６６部を添加し、攪拌し、ろ過した。回収されたろ液を濃縮することにより、淡黄色オイル４２.２６部を得た。
得られた淡黄色オイルにアセトニトリル４２.２６部を添加し、均一化し、メチル−ｔ−ブチルエーテルを１２６.７８部加え、撹拌して静置した。二層に分離した下層を回収し、さらにアセトニトリル４２.２６部を添加し、均一化した。その後、メチル−ｔ−ブチルエーテルを１２６.７８部加え撹拌し、静置した。二層に分離した下層を集め濃縮し、撹拌してろ過した。これにより、白色固体として、化合物（ａａ−１−１）８.５３部（収率２０％）を得た。化合物（ａａ−１−１）をＡ２とした。 [Synthesis of Acid Generator A2]

10.00 parts of compound (aa-1-b), 120.00 parts of monochlorobenzene and 16.0 parts of compound (aa-1-a) were charged, and 1.40 parts of sulfuric acid were charged at 23 ° C. with stirring. The temperature was raised to ° C and concentrated. To the resulting reaction product, 4.00 parts of molecular sieve (4A Wako Pure Chemical Industries, Ltd.) was added, dehydrated at 125 ° C. for 8 hours, and concentrated. To the obtained concentrate, 166 parts of chloroform and 83 parts of ion-exchanged water were added, washed, and separated to recover the organic layer. This washing with water was performed a total of 6 times. To the collected organic layer, 1.66 parts of activated carbon was added, stirred and filtered. The collected filtrate was concentrated to obtain 42.26 parts of pale yellow oil.
To the obtained pale yellow oil, 42.26 parts of acetonitrile was added and homogenized, and 126.78 parts of methyl-t-butyl ether was added, stirred and allowed to stand. The lower layer separated into two layers was recovered, and 42.26 parts of acetonitrile was further added to make uniform. Thereafter, 126.78 parts of methyl-t-butyl ether was added and stirred and allowed to stand. The lower layer separated into two layers was collected, concentrated, stirred and filtered. This obtained 8.53 parts (yield 20%) of compound (aa-1-1) as a white solid. Compound (aa-1-1) was designated as A2.

MS (ESI (+) Spectrum): M ⁺ 263.1
MS (ESI (-) Spectrum): M ^- 347.0
¹ H-NMR (chloroform-d, internal standard substance tetramethylsilane): δ (ppm) 1.77-1.79 (m, 1H), 2.03-2.07 (m, 1H), 2.16 -2.21 (m, 1H), 2.27-2.29 (m, 1H), 2.65 (m, 1H), 3.45-3.47 (m, 1H), 3.50-3 .53 (m, 1H), 4.77 (m, 1H), 4.82-4.83 (m, 1H), 7.71-7.81 (m, 15H)

  The following compound G corresponds to the compound represented by the formula (aa) of the present invention.

[Synthesis of Resin B1]
Monomer E, monomer F, monomer B, monomer G, and monomer D were charged at a molar ratio of 28: 14: 6: 21: 31, and 1.5 weight times dioxane of the total monomer amount was added to obtain a solution. 1 mol% and 3 mol% of azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added to the total monomer amount, respectively, and heated at 75 ° C. for about 5 hours. Thereafter, the reaction solution was purified by pouring it into a mixed solvent of a large amount of methanol and water three times to obtain a copolymer having a weight average molecular weight of 8.0 × 10 ^{3 in} a yield of 70%. . This copolymer has a repeating unit derived from the monomer of the following formula, and this is designated as resin B1.

[Synthesis of Resin B2]
Monomer F, monomer E, monomer B, monomer G and monomer C are charged in a molar ratio of 40: 10: 8: 26: 16, and then 1.2 mass times dioxane with respect to the total mass of all monomers. Was added. 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. This was heated at 75 ° C. for about 5 hours. Thereafter, the reaction solution was purified by pouring it into a large amount of methanol / water mixed solvent and precipitating three times to obtain a copolymer having a weight average molecular weight of about 7.0 × 10 ^{3 in} a yield of 60%. I got it. The obtained copolymer has a structural unit derived from each monomer of the following formula, and this was designated as resin B2.

[Synthesis of Resin B3]
Monomer F, monomer E, monomer B, monomer G and monomer C are charged at a molar ratio of 40: 10: 8: 16: 26, and then 1.2 mass times dioxane with respect to the total mass of all monomers. Was added. 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. This was heated at 75 ° C. for about 5 hours. Thereafter, the reaction solution was purified by pouring it into a large amount of methanol / water mixed solvent for precipitation three times to obtain a copolymer having a weight average molecular weight of about 6.8 × 10 ^{3 in} a yield of 68%. I got it. The obtained copolymer has a structural unit derived from each monomer of the following formula, and this was designated as resin B3.

[Synthesis of Resin B4]
Monomer F, monomer E, monomer B, monomer G, monomer D and monomer C are charged in a molar ratio of 40: 10: 8: 10: 22: 10, and then 1. Two times as much dioxane was added. 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. This was heated at 75 ° C. for about 5 hours. Thereafter, the reaction solution was purified by pouring it into a large amount of methanol / water mixed solvent and precipitating three times to obtain a copolymer having a weight average molecular weight of about 6.9 × 10 ^{3 in} a yield of 70%. I got it. The obtained copolymer has a structural unit derived from each monomer of the following formula, and this was designated as resin B4.

[Synthesis of Resin B5]
Monomer E, monomer F, monomer I, monomer G and monomer D are charged in a molar ratio of 40: 10: 8: 26: 16, and then 1.2 mass times dioxane with respect to the total mass of all monomers. Was added. 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. This was heated at 75 ° C. for about 5 hours. Thereafter, the reaction solution was purified by pouring it into a large amount of methanol / water mixed solvent and precipitating three times to obtain a copolymer having a weight average molecular weight of about 7.4 × 10 ^{3 in} a yield of 68%. I got it. The obtained copolymer has a structural unit derived from each monomer of the following formula, and this was designated as resin B5.

[Synthesis of Resin B6]
Monomer E, monomer F, monomer I, monomer G and monomer D are charged in a molar ratio of 40: 10: 5: 25: 20, and then 1.2 mass times dioxane with respect to the total mass of all monomers. Was added. 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. This was heated at 75 ° C. for about 5 hours. Thereafter, the reaction solution was purified by pouring it into a large amount of methanol / water mixed solvent and precipitating three times to obtain a copolymer having a weight average molecular weight of about 7.2 × 10 ^{3 in} a yield of 72%. Got in. The obtained copolymer has a structural unit derived from each monomer of the following formula, and this was designated as resin B6.

[Synthesis of Resin B7]
Monomer E, monomer F, monomer I, monomer B, monomer G and monomer D are charged in a molar ratio of 40: 10: 4: 4: 22: 20, and then 1. Two times as much dioxane was added. 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. This was heated at 75 ° C. for about 5 hours. Then, the reaction solution was purified by performing the operation of pouring into a large amount of methanol / water mixed solvent and precipitating three times to obtain a copolymer having a weight average molecular weight of about 7.3 × 10 ^{3 in} a yield of 65%. I got it. The obtained copolymer has a structural unit derived from each monomer of the following formula, and this was designated as resin B7.

[Synthesis of Resin B8]
Monomer A, monomer F, monomer B, monomer G, and monomer D were charged at a molar ratio of 30: 14: 6: 20: 30, and 1.5 weight times dioxane of the total monomer amount was added to obtain a solution. 1 mol% and 3 mol% of azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added to the total monomer amount, respectively, and heated at 75 ° C. for about 5 hours. Thereafter, the reaction solution was purified by pouring it into a mixed solvent of a large amount of methanol and water three times to obtain a copolymer having a weight average molecular weight of 7.0 × 10 ³ at a yield of 78%. . This copolymer has a repeating unit derived from the monomer of the following formula, and this is designated as resin B8.

[Synthesis of Resin B9]
Monomer A, monomer J, and monomer G were charged at a molar ratio of 52.6: 15.8: 31.6, and 1.5 times by weight of dioxane was added to the total monomer amount to obtain a solution. 1 mol% and 3 mol% of azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added to the total monomer amount, respectively, and heated at 78 ° C. for about 5 hours. Thereafter, the reaction solution was purified by pouring it into a mixed solvent of a large amount of methanol and water three times to obtain a copolymer having a weight average molecular weight of 7.3 × 10 ^{3 in} a yield of 68%. . This copolymer has a repeating unit derived from the monomer of the following formula, and this is designated as resin B9.

[Synthesis of Resin X1]
Monomer E, monomer F, monomer B, monomer C, and monomer D were charged at a molar ratio of 28: 14: 6: 21: 31, and 1.5 weight times dioxane of the total monomer amount was added to obtain a solution. 1 mol% and 3 mol% of azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added to the total monomer amount, respectively, and heated at 75 ° C. for about 5 hours. Thereafter, the reaction solution was purified by pouring it into a mixed solvent of a large amount of methanol and water three times to obtain a copolymer having a weight average molecular weight of 8.5 × 10 ^{3 in} a yield of 74%. . This copolymer has each structural repeating unit derived from the monomer of the following formula, and this is designated as resin X1.

[Synthesis of Resin X2]
Monomer A, monomer B, and monomer D were charged at a molar ratio of 50:25:25, and 1.5 weight times dioxane of the total monomer amount was added to prepare a solution. 1 mol% and 3 mol% of azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added to the total monomer amount, respectively, and heated at 77 ° C. for about 5 hours. Thereafter, the reaction solution was purified by pouring it into a mixed solvent of a large amount of methanol and water three times to obtain a copolymer having a weight average molecular weight of 8.1 × 10 ^{3 in} a yield of 55%. . This copolymer has a repeating unit derived from the monomer of the following formula, and this is designated as resin X2.

Examples and Comparative Examples The following components were mixed and dissolved, and further filtered through a fluororesin filter having a pore size of 0.2 μm to prepare a resist composition.

Ａ２：

<Acid generator>
A1:

A2:

Ａ４：

Ａ５：

Ａ６：

A3:

A4:

A5:

A6:

Y1:

<Basic compound: Quencher>
Q1: 2,6-diisopropylaniline <Solvent of resist composition in Table 1>
Propylene glycol monomethyl ether acetate 265 parts 2-heptanone 20.0 parts Propylene glycol monomethyl ether 20.0 parts γ-butyrolactone 3.5 parts <Solvent of resist composition in Table 2>
Propylene glycol monomethyl ether acetate 264 parts 2-heptanone 20.0 parts Propylene glycol monomethyl ether 20.0 parts γ-butyrolactone 3.5 parts <Solvents of resist compositions in Tables 3 to 5>
Propylene glycol monomethyl ether acetate 265 parts 2-heptanone 20.0 parts Propylene glycol monomethyl ether 20.0 parts γ-butyrolactone 3.5 parts

(Evaluation of resist composition)
An organic antireflective coating composition (ARC-29; manufactured by Nissan Chemical Co., Ltd.) is applied to a silicon wafer and baked at 205 ° C. for 60 seconds to form an organic antireflective coating having a thickness of 78 nm. Formed.
Next, the above resist composition was spin-coated on the organic antireflection film so that the film thickness after drying was 85 nm.

After applying the resist composition, the obtained silicon wafer was pre-baked (PB) for 60 seconds at a temperature described in the “PB” column of Table 1 on a direct hot plate. Using an ArF excimer stepper (FPA5000-AS3; manufactured by Canon Inc., NA = 0.75, 2/3 Annual) on the silicon wafer on which the resist composition film was formed in this manner, the exposure amount was changed stepwise. The line and space pattern was exposed.
After exposure, post-exposure baking (PEB) was performed for 60 seconds on a hot plate at the temperature described in the “PEB” column of Table 1, and further with a 2.38 wt% tetramethylammonium hydroxide aqueous solution for 60 seconds. Paddle development was performed.

The dark field pattern after development on the organic antireflection film substrate was observed with a scanning electron microscope. The results are shown in Table 2.
The dark field pattern referred to here is obtained by exposure and development through a reticle having a glass surface (translucent portion) formed in a line shape on the outside with a chromium layer (light-shielding layer) as a base. Accordingly, after exposure and development, the resist layer around the line and space pattern remains.
Effective sensitivity: The exposure amount at which a 100 nm line and space pattern is 1: 1 is shown.

  Shape evaluation: Exposure was performed with an exposure amount at which a 100 nm line and space pattern was 1: 1, and the resist pattern was observed with a scanning electron microscope. A case where the top shape and the skirt shape were close to a rectangle was good, and a case where the top shape was round or close to a T-shape or a skirt was seen was judged as x.

Focus margin evaluation (DOF): A range in which the line width is 90 nm ± 5% when the focus is shaken with an exposure amount at which the line width of a line-and-space pattern with a mask size of 90 nm is 90 nm (approximately 85.5%). ~ 94.5nm) as the line width index, ◎ when the DOF is 0.90μm or more, ◯ when the DOF is 0.60μm or more and less than 0.90μm, DOF is 0.30μm or more and less than 0.60μm Some were marked as Δ, and less than 0.30 μm as x.
These results are shown in Table 6.

(Evaluation of immersion resist composition)
Similar to the above-described examples, an organic antireflection film and a resist composition film were formed on a silicon wafer.
The obtained silicon wafer was pre-baked (PB) for 60 seconds on a direct hot plate at the temperature described in the “PB” column of Table 2. An ArF excimer stepper for immersion exposure [XT: 1900 Gi; manufactured by ASML, NA = 1.35, 3/4 Annular XY deflection] was used on the silicon wafer on which the film of the resist composition was thus formed. The line and space pattern was exposed by changing the exposure amount stepwise.
After the exposure, post exposure bake (PEB) is performed on the hot plate at the temperature described in the “PEB” column of Table 2 for 60 seconds, and further with a 2.38 wt% tetramethylammonium hydroxide aqueous solution for 60 seconds. Paddle development was performed.

Effective sensitivity: The exposure amount at which the line and space pattern of 50 nm is 1: 1 is shown.
Evaluation of resolution: In terms of effective sensitivity, the resist pattern was observed with a scanning electron microscope, and a resolution of 45 nm was evaluated as ◯ and a resolution of 45 nm was not evaluated as ×.

  Pattern collapse evaluation (PCM): In a 45 nm line and space pattern, when the exposure amount is increased, the pattern width disappears when the line width becomes thinner than 38 nm, and the pattern disappearance due to falling or peeling is not observed. Then, the case where pattern disappearance due to falling or peeling was observed was taken as x.

Focus margin evaluation (DOF): When the focus is moved in the effective sensitivity, the range (47.5-52.5 nm) where the line width is 50 nm ± 5% is used as the line width index, and the DOF is 0.15 μm or more. Is ◯, 0.10 μm or more and less than 0.15 μm is Δ, and 0.10 μm or less is ×.
These results are shown in Table 7.

(Evaluation of immersion resist composition)
Similar to the above-described examples, an organic antireflection film and a resist composition film were formed on a silicon wafer.
The obtained resist composition film was pre-baked on a direct hot plate at a temperature described in the “PB” column of Table 3 for 60 seconds to form a resist film. An ArF excimer stepper for immersion exposure (XT: 1900 Gi; manufactured by ASML, NA = 1.35, 3/4 Annular XY deflection) is used to form a contact hole pattern (hole pitch 100 nm / hole) on a silicon wafer on which a resist film is formed. Using a mask for forming a hole diameter of 70 nm, exposure was performed while changing the exposure amount stepwise.
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 3.
Next, this silicon wafer was subjected to paddle development for 60 seconds with a 2.38% tetramethylammonium hydroxide aqueous solution.

  In each resist film, an exposure amount at which the hole diameter of a pattern formed with a mask having a hole diameter of 70 nm was 55 nm was defined as effective sensitivity.

  Evaluation of resolution: In the case of resolving a pattern formed with a mask having a hole diameter smaller than 67 nm with reference to a pattern formed with a mask having a hole diameter of 70 nm as a reference in effective sensitivity. ◯, Δ when a pattern formed with a mask having a hole diameter of 67 nm or more and less than 70 nm is resolved, and × when a pattern formed with a mask with a hole diameter smaller than 70 nm is not resolved.

  Pattern evaluation (PCM): In a hole pattern formed with a mask having a hole diameter of 70 nm, when the exposure amount is increased, the pattern is formed even if the hole line width is larger than 60 nm. A pattern in which a pattern with a width exceeding 57 nm and 60 nm or less was formed was indicated by Δ, and a pattern having a line width of 57 nm or less and connected to an adjacent pattern or a pattern disappearance due to peeling was indicated by ×.

Mask error factor (MEF) evaluation: In the effective sensitivity, the mask hole diameter of a pattern formed with a mask having a hole diameter of 72 nm, 71 nm, 70 nm, 69 nm, and 68 nm, respectively, is plotted on the horizontal axis, and the hole diameter of each pattern is plotted on the vertical axis. The slope of the straight line when plotted was calculated as MEF. A case where the slope was less than 2.8 was judged as ◯, a case where the slope was 2.8 or more and less than 3.0 was judged as Δ, and a case where the slope was larger than 3.0 was judged as ×.
These results are shown in Table 8.

(Evaluation of immersion resist composition)
Similar to the above-described examples, an organic antireflection film and a resist composition film were formed on a silicon wafer.
The obtained silicon wafer was pre-baked (PB) for 60 seconds on a direct hot plate at the temperature described in the “PB” column of Table 4. A contact hole is formed on the silicon wafer on which the resist composition film is formed in this manner, using an ArF excimer stepper for immersion exposure (XT: 1900 Gi; manufactured by ASML, NA = 1.35, 3/4 Annular XY deflection). Using a mask for forming a pattern (hole pitch 100 nm / hole diameter 70 nm), exposure was carried out while changing the exposure amount stepwise.
After the exposure, post-exposure baking (PEB) was performed for 60 seconds on the hot plate at the temperature described in the “PEB” column of Table 4, and further with a 2.38 wt% tetramethylammonium hydroxide aqueous solution for 60 seconds. Paddle development was performed.

  In each resist film, an exposure amount at which the hole diameter of a pattern formed with a mask having a hole diameter of 70 nm was 55 nm was defined as effective sensitivity.

  Evaluation of resolution: In the case of resolving a pattern formed with a mask having a hole diameter smaller than 67 nm with reference to a pattern formed with a mask having a hole diameter of 70 nm as a reference in effective sensitivity. ◯, Δ when a pattern formed with a mask having a hole diameter of 67 nm or more and less than 70 nm is resolved, and × when a pattern formed with a mask with a hole diameter smaller than 70 nm is not resolved.

Focus margin (DOF) evaluation: In the effective sensitivity, the focus range where the hole diameter is 52.2 nm or more and 57.7 nm or less is set as DOF, and when DOF is larger than 0.18 μm, ○, 0.15 μm or more and 0.18 μm or less The case was judged as Δ, and the case less than 0.15 μm was judged as x.
These results are shown in Table 9.

(Evaluation of immersion resist composition)
Similar to the above-described examples, an organic antireflection film and a resist composition film were formed on a silicon wafer.
The obtained silicon wafer was pre-baked (PB) for 60 seconds on the direct hot plate at the temperature described in the “PB” column of Table 5. An ArF excimer stepper for immersion exposure [XT: 1900 Gi; manufactured by ASML, NA = 1.35, 3/4 Annular XY deflection] was used on the silicon wafer on which the film of the resist composition was thus formed. The line and space pattern was subjected to immersion exposure by changing the exposure amount stepwise.
After exposure, on the hot plate, post exposure bake (PEB) was performed for 60 seconds at the temperature described in the “PEB” column of Table 5, and further with a 2.38 wt% tetramethylammonium hydroxide aqueous solution for 60 seconds. Paddle development was performed.

Effective sensitivity: The exposure amount at which the line and space pattern of 50 nm is 1: 1 is shown.
Evaluation of resolution: In terms of effective sensitivity, the resist pattern was observed with a scanning electron microscope, and a resolution of 45 nm was evaluated as ◯ and a resolution of 45 nm was not evaluated as ×.

  Shape evaluation: A 50 nm line and space pattern was observed with a scanning electron microscope. A case where the top shape and the skirt shape were close to a rectangle was good, and a case where the top shape was round or close to a T-shape or a skirt was seen was judged as x.

Focus margin evaluation (DOF): When the focus is moved in the effective sensitivity, the range (47.5-52.5 nm) where the line width is 50 nm ± 5% is used as the line width index, and the DOF is 0.15 μm or more. Is ◯, 0.10 μm or more and less than 0.15 μm is Δ, and 0.10 μm or less is ×.
These results are shown in Table 10.

  According to the resist composition of the present invention, a pattern having an excellent shape and DOF can be formed.

Claims (7)

A resist composition comprising an acid generator (A) containing a salt represented by formula (I) as an active ingredient and a resin (B) having a repeating unit derived from a compound represented by formula (aa).

[In the formula (I),
Q ¹ and Q ² each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group.
X ¹ represents a C 1-17 divalent saturated hydrocarbon group which may have a substituent, and —CH ₂ — contained in the saturated hydrocarbon group is —O— or —CO—. It may be replaced with.
Y ¹ is an aliphatic hydrocarbon group having 1 to 36 carbon atoms, an alicyclic hydrocarbon group having 3 to 36 carbon atoms, or an aromatic hydrocarbon group having 6 to 36 carbon atoms, the aliphatic hydrocarbon group, The alicyclic hydrocarbon group and the aromatic hydrocarbon group may have a substituent, and —CH ₂ — contained in the aliphatic hydrocarbon group and the alicyclic hydrocarbon group is —CO—. , —O—, —S—, —SO ₂ — or —N (R ^c ) — may be substituted.
R ^c represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
Z ⁺ represents an organic counter cation. ]

[In the formula (aa)
T represents an alicyclic hydrocarbon group having 4 to 36 carbon atoms, and the hydrogen atom contained in the alicyclic hydrocarbon group may be substituted with a halogen atom, a hydroxyl group, a halogen atom or a hydroxyl group. An alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, a glycidyloxy group, an acyl group having 2 to 4 carbon atoms, and an alkoxycarbonyl group , An alkanoyloxyalkyl group or a cyano group, and —CH ₂ — contained in the alicyclic hydrocarbon group is replaced by at least one —SO ₂ —, and —CO—, -O -, - S -, - SO 2 - or -N ^{(R c)} - it may be replaced by.
R ^c represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
R ¹ represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom. ] The resist composition according to claim 1, wherein T is a group represented by the formula (T1).

[In the formula (T1),
The hydrogen atom contained in the ring is a halogen atom, a hydroxyl group, an alkyl group having 1 to 12 carbon atoms which may be substituted with a halogen atom or a hydroxyl group, an alkoxy group having 1 to 12 carbon atoms, or an aryl group having 6 to 12 carbon atoms. , An aralkyl group having 7 to 12 carbon atoms, a glycidyloxy group, an acyl group having 2 to 4 carbon atoms, an alkoxycarbonyl group, an alkanoyloxyalkyl group, or a cyano group, and —CH ₂ — included in the ring Is replaced by at least one —SO ₂ —, and may be further replaced by —CO—, —O—, —S—, —SO ₂ — or —N (R ^c ) —.
R ^c represents the same meaning as described above.
* Represents a bond with an oxygen atom.
T ¹ represents an oxygen atom or —CH ₂ —. ] The resist composition according to claim 1, wherein T is a group represented by the formula (T2).

[In the formula (T2),
The hydrogen atom contained in the ring is a halogen atom, a hydroxyl group, an alkyl group having 1 to 12 carbon atoms which may be substituted with a halogen atom or a hydroxyl group, an alkoxy group having 1 to 12 carbon atoms, or an aryl group having 6 to 12 carbon atoms. , An aralkyl group having 7 to 12 carbon atoms, a glycidyloxy group, an acyl group having 2 to 4 carbon atoms, an alkoxycarbonyl group, an alkanoyloxyalkyl group, or a cyano group, and —CH ₂ — included in the ring May be replaced by a carbonyl group, an oxygen atom, a sulfur atom, —SO ₂ — or —N (R ^c ) —.
R ^c and * represent the same meaning as described above. ]   The resin (B) is a resin that further has an acid-labile group, 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. The resist composition described in 1.   Furthermore, the resist composition in any one of Claims 1-4 containing a basic compound. (1) The process of apply | coating the resist composition containing resin (B) which has a repeating unit derived from the compound represented by Formula (aa) on a board | substrate,
(2) a step of removing the solvent from the composition after coating to form a composition layer;
(3) a step of exposing the composition layer using an exposure machine;
(4) A step of heating the composition layer after exposure,
(5) A pattern forming method including a step of developing the heated composition layer using a developing device.

[In the formula (aa)
T represents an alicyclic hydrocarbon group having 4 to 36 carbon atoms, and the hydrogen atom contained in the alicyclic hydrocarbon group includes a halogen atom, a hydroxyl group, an alkyl group having 1 to 12 carbon atoms, and 1 to 1 carbon atoms. The alicyclic hydrocarbon group may be substituted with an alkoxy group having 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, a glycidyloxy group, or an acyl group having 2 to 4 carbon atoms. —CH ₂ — contained in is substituted with at least one —SO ₂ —, and further substituted with a carbonyl group, an oxygen atom, a sulfur atom, —SO ₂ — or —N (R ^c ) —. Also good.
R ^c represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
R ¹ represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom. ] The pattern formation method of Claim 6 in which a resist composition contains the acid generator (A) which uses the salt represented by Formula (I) as an active ingredient further.

[In the formula (I),
Q ¹ and Q ² each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group.
X ¹ represents a C 1-17 divalent saturated hydrocarbon group which may have a substituent, and —CH ₂ — contained in the saturated hydrocarbon group is —O— or —CO—. It may be replaced with.
Y ¹ is an aliphatic hydrocarbon group having 1 to 36 carbon atoms, an alicyclic hydrocarbon group having 3 to 36 carbon atoms, or an aromatic hydrocarbon group having 6 to 36 carbon atoms, the aliphatic hydrocarbon group, The alicyclic hydrocarbon group and the aromatic hydrocarbon group may have a substituent, and —CH ₂ — contained in the aliphatic hydrocarbon group and the alicyclic hydrocarbon group is —CO—. , —O—, —S—, —SO ₂ — or —N (R ^c ) — may be substituted.
R ^c represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
Z ⁺ represents an organic counter cation. ]