JP2018012688A - Salt, acid generator, resist composition, and method for producing resist pattern - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a salt capable of producing a resist pattern with good CD uniformity (CDU), and a resist composition containing the salt.SOLUTION: The salt has a group represented by formula (aa1) [where Xand Xeach independently represent an oxygen atom or a sulfur atom; ring Wrepresents a 3-36C heterocyclic ring having an ester bond or a thioester bond in the ring structure, wherein -CH- contained in the heterocyclic ring may be substituted with -O-, -S-, -CO- or -SO- and the heterocyclic ring may have a substituent; ring Wrepresents a 3-36C alicyclic hydrocarbon group which may have a substituent, wherein -CH- contained in the alicyclic hydrocarbon group may be substituted with -O-, -S-, -CO- or -SO-, provided that the ring Whas at least one base-dissociable group; and * represents a bond].SELECTED DRAWING: None

Description

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

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

JP 2014-189534 A

  In the resist composition containing the above salt, the CD uniformity (CDU) of the resulting resist pattern may not always be satisfied.

［式（ａａ１）中、
Ｘ^a及びＸ^bは、それぞれ独立に、酸素原子又は硫黄原子を表す。
環Ｗ^１は、エステル結合又はチオエステル結合を環の構成に有する炭素数３〜３６の複素環を表し、該複素環に含まれる−ＣＨ_２−は、−Ｏ−、−Ｓ−、−ＣＯ−又は−ＳＯ_２−で置換されていてもよく、該複素環は置換基を有していてもよい。
環Ｗ^２は、置換基を有していてもよい炭素数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、−Ｏ−、−Ｓ−、−ＣＯ−又は−ＳＯ_２−で置換されていてもよい。ただし、環Ｗ^２は、少なくとも１つの塩基解離性基を有する。
＊は、結合手を表す。］
［２］ 式（ａａ１）で表される基を有するアニオンとカチオンとからなる［１］に記載の塩。
［３］ 式（ａａ１）で表される基を有するアニオンが、式（ａａ１）で表される基とスルホナートとを有するアニオンである［２］に記載の塩。
［４］ 式（ａａ１）で表される基を有する塩が、式（ａａ２）で表されるアニオンを有する塩である［１］に記載の塩。

［式（ａａ２）中、
Ｘ^a、Ｘ^b、環Ｗ^１及び環Ｗ^２は、上記と同じ意味を表す。
Ｌ^b1は、炭素数１〜２４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−に置き換わっていてもよく、該飽和炭化水素基に含まれる水素原子は、フッ素原子又はヒドロキシ基で置換されていてもよい。
Ｑ¹及びＱ²は、それぞれ独立に、フッ素原子又は炭素数１〜６のペルフルオロアルキル基を表す。］
［５］ 塩基解離性基が、式（Ｂａ）で表される基又は式（Ｂｂ）で表される基である［１］〜［４］のいずれか記載の塩。

［式（Ｂａ）中、Ｒ²³は、フッ素原子を有する炭素数１〜６のアルキル基を表す。
式（Ｂｂ）中、Ｒ²⁴は、フッ素原子を有する炭素数１〜６のアルキル基を表す。
Ｒ²⁵及びＲ²⁶は、それぞれ独立に、フッ素原子を有していてもよい炭素数１〜６のアルキル基、水素原子又はフッ素原子を表す。］
［６］ 環Ｗ^１が、式（Ｗ−１）で表される複素環又は式（Ｗ−２）で表される複素環である［１］〜［５］のいずれかに記載の塩。

［式（Ｗ−１）及び式（Ｗ−２）中、
複素環に含まれる水素原子は、ヒドロキシ基、シアノ基、カルボキシル基、炭素数１〜１２のアルキル基、炭素数１〜１２のアルコキシ基、炭素数３〜１２の脂環式炭化水素基、又は炭素数６〜１０の芳香族炭化水素基で置換されていてもよい。］
［７］ 環Ｗ^２が、式（ｗ１−１）で表される環、式（ｗ１−２）で表される環、式（ｗ１−３）で表される環又は式（ｗ１−６）で表される環である［１］〜［６］のいずれかに記載の塩。

［式（ｗ１−１）、式（ｗ１−２）、式（ｗ１−３）及び式（ｗ１−６）中、
環に含まれる−ＣＨ_２−は、−Ｏ−、−Ｓ−、−ＣＯ−又は−ＳＯ_２−で置換されていてもよく、
環は少なくとも１つの塩基解離性基を有しており、ヒドロキシ基、炭素数１〜１２のアルキル基、炭素数１〜１２のアルコキシ基、炭素数２〜１３のアルコキシカルボニル基、炭素数２〜１３のアルキルカルボニル基、炭素数２〜１３のアルキルカルボニルオキシ基、炭素数３〜１２の脂環式炭化水素基及び炭素数６〜１０の芳香族炭化水素基からなる群より選ばれる１以上の置換基を有していてもよい。］
［８］ Ｌ^b1が、＊１−ＣＯ−Ｏ−（ＣＨ₂）_t−（ｔは０〜６のいずれかの整数を表す。＊１は、−Ｃ（Ｑ¹）（Ｑ²）−との結合手を表す。）である［５］〜［７］のいずれかに記載の塩。
［９］ ［１］〜［８］のいずれかに記載の塩を含有する酸発生剤。
［１０］ ［９］に記載の酸発生剤と酸不安定基を有する樹脂とを含有するレジスト組成物。
［１１］ さらに、酸発生剤から発生する酸よりも酸性度の弱い酸を発生する塩を含有する［１０］に記載のレジスト組成物。
［１２］（１）［１０］又は［１１］記載のレジスト組成物を基板上に塗布する工程、
（２）塗布後の組成物を乾燥させて組成物層を形成する工程、
（３）組成物層に露光する工程、
（４）露光後の組成物層を加熱する工程、及び
（５）加熱後の組成物層を現像する工程、
を含むレジストパターンの製造方法。 The present invention includes the following inventions.
[1] A salt having a group represented by the formula (aa1).

[In the formula (aa1),
X ^a and X ^b each independently represent an oxygen atom or a sulfur atom.
Ring W ¹ represents a C3-C36 heterocyclic ring having an ester bond or a thioester bond in the ring structure, and —CH ₂ — contained in the heterocyclic ring is —O—, —S—, —CO—. or -SO 2 _- may be substituted with, the heterocyclic ring may have a substituent.
Ring W ² represents an alicyclic hydrocarbon group having 3 to 36 carbon atoms which may have a substituent, and —CH ₂ — contained in the alicyclic hydrocarbon group is —O—, — S -, - CO- or -SO ₂ - may be substituted with. However, the ring W ² has at least one base-dissociable group.
* Represents a bond. ]
[2] The salt according to [1], comprising an anion having a group represented by the formula (aa1) and a cation.
[3] The salt according to [2], wherein the anion having a group represented by the formula (aa1) is an anion having a group represented by the formula (aa1) and a sulfonate.
[4] The salt according to [1], wherein the salt having a group represented by the formula (aa1) is a salt having an anion represented by the formula (aa2).

[In the formula (aa2),
X ^a , X ^b , ring W ¹ and ring W ² represent the same meaning as described above.
L ^b1 represents a divalent saturated hydrocarbon group having 1 to 24 carbon atoms, and —CH ₂ — contained in the saturated hydrocarbon group may be replaced by —O— or —CO—, and The hydrogen atom contained in the hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
Q ¹ and Q ² each independently represents a fluorine atom or a C 1-6 perfluoroalkyl group. ]
[5] The salt according to any one of [1] to [4], wherein the base dissociable group is a group represented by the formula (Ba) or a group represented by the formula (Bb).

[In Formula (Ba), R ²³ represents a C 1-6 alkyl group having a fluorine atom.
In the formula (Bb), R ²⁴ represents a C 1-6 alkyl group having a fluorine atom.
R ²⁵ and R ²⁶ each independently represents an alkyl group having 1 to 6 carbon atoms which may have a fluorine atom, a hydrogen atom or a fluorine atom. ]
[6] The salt according to any one of [1] to [5], wherein the ring W ¹ is a heterocycle represented by the formula (W-1) or a heterocycle represented by the formula (W-2).

[In Formula (W-1) and Formula (W-2),
The hydrogen atom contained in the heterocyclic ring is a hydroxy group, a cyano group, a carboxyl group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms, or It may be substituted with an aromatic hydrocarbon group having 6 to 10 carbon atoms. ]
[7] Ring W ² is a ring represented by formula (w1-1), a ring represented by formula (w1-2), a ring represented by formula (w1-3), or formula (w1-6) The salt according to any one of [1] to [6], which is a ring represented by:

[In formula (w1-1), formula (w1-2), formula (w1-3) and formula (w1-6),
—CH ₂ — contained in the ring may be substituted with —O—, —S—, —CO— or —SO ₂ —,
The ring has at least one base dissociable group, and is a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alkoxycarbonyl group having 2 to 13 carbon atoms, or 2 to 2 carbon atoms. One or more selected from the group consisting of 13 alkylcarbonyl groups, C2-13 alkylcarbonyloxy groups, C3-12 alicyclic hydrocarbon groups, and C6-10 aromatic hydrocarbon groups It may have a substituent. ]
[8] L ^b1 represents * 1-CO—O— (CH ₂ ) _t — (t represents an integer of 0 to 6. * 1 represents —C (Q ¹ ) (Q ² ) — The salt according to any one of [5] to [7].
[9] An acid generator containing the salt according to any one of [1] to [8].
[10] A resist composition comprising the acid generator according to [9] and a resin having an acid labile group.
[11] The resist composition according to [10], further comprising a salt that generates an acid having a lower acidity than an acid generated from an acid generator.
[12] (1) A step of applying the resist composition according to [10] or [11] on a substrate,
(2) The process of drying the composition after application | coating and forming a composition layer,
(3) a step of exposing the composition layer;
(4) a step of heating the composition layer after exposure, and (5) a step of developing the composition layer after heating,
A method for producing a resist pattern including:

  A salt capable of producing a resist pattern with good CD uniformity (CDU) is provided.

In the present specification, "(meth) acrylic monomer" means at least one monomer having a "CH ₂ = CH-CO-" or _{"CH 2 = C (CH 3)} -CO- " structure of To do. 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. Moreover, in the group described in the present specification, any group that can take both a linear structure and a branched structure may be used. When stereoisomers exist, all stereoisomers are included.
In the present specification, the “solid content of the resist composition” means the total of components excluding the solvent (E) described later from the total amount of the resist composition.

［式（ａａ１）中、
Ｘ^a及びＸ^bは、それぞれ独立に、酸素原子又は硫黄原子を表す。
環Ｗ^１は、エステル結合又はチオエステル結合を環の構成に有する炭素数３〜３６の複素環を表し、該複素環に含まれる−ＣＨ_２−は、−Ｏ−、−Ｓ−、−ＣＯ−又は−ＳＯ_２−で置換されていてもよく、該複素環は置換基を有していてもよい。
環Ｗ^２は、置換基を有していてもよい炭素数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、−Ｏ−、−Ｓ−、−ＣＯ−又は−ＳＯ_２−で置換されていてもよい。ただし、環Ｗ^２は、少なくとも１つの塩基解離性基を有する。
＊は、結合手を表す。］ <Salt (aa)>
The salt of the present invention is a salt having a group represented by the following formula (aa1) (hereinafter sometimes referred to as “salt (aa)”).

[In the formula (aa1),
X ^a and X ^b each independently represent an oxygen atom or a sulfur atom.
Ring W ¹ represents a C3-C36 heterocyclic ring having an ester bond or a thioester bond in the ring structure, and —CH ₂ — contained in the heterocyclic ring is —O—, —S—, —CO—. or -SO 2 _- may be substituted with, the heterocyclic ring may have a substituent.
Ring W ² represents an alicyclic hydrocarbon group having 3 to 36 carbon atoms which may have a substituent, and —CH ₂ — contained in the alicyclic hydrocarbon group is —O—, — S -, - CO- or -SO ₂ - may be substituted with. However, the ring W ² has at least one base-dissociable group.
* Represents a bond. ]

X ^a and X ^b are preferably the same atom, and more preferably an oxygen atom.

Ring W ¹ represents a heterocycle of 3 to 36 carbon atoms containing an ester bond or thioester bond to the configuration of the ring. The heterocyclic ring in the ring W ¹ may be monocyclic or polycyclic.
Examples of the ring W ¹ include a lactone ring, a thiolactone ring, a condensed ring of a lactone ring and other rings, a condensed ring of a thiolactone ring and other rings, and the like. -The heterocyclic ring represented by Formula (W-15) is mentioned. Especially, the heterocyclic ring represented by Formula (W-1) or the heterocyclic ring represented by Formula (W-2) is preferable.

炭素数６〜１０の芳香族炭化水素基としては、フェニル基、ナフチル基が挙げられる。
これらを組み合わせた基としては、メトキシメチル基、メトキシエチル基、エトキシエチル基、エトキシメチル基等の炭素数２〜２４のアルコキシアルキル基；メトキシメトキシ基、メトキシエトキシ基、エトキシメトキシ基、エトキシエトキシ基等の炭素数２〜２４のアルコキシアルコキシ基；ヒドロキシメチル基、ヒドロキシエチル基等の炭素数１〜１２のヒドロキシアルキル基等が挙げられる。
環Ｗ^１の置換基は、ヒドロキシ基、シアノ基又は炭素数１〜１２のアルコキシ基であることが好ましく、ヒドロキシ基又はシアノ基であることがより好ましく、ヒドロキシ基であることがさらに好ましい。 The heterocyclic ring represented by ring W ¹ may have a substituent, and examples of the substituent include groups described in group A.
Group A: hydroxy group, cyano group, alkyl group having 1 to 12 carbon atoms, alkoxy group having 1 to 12 carbon atoms, alicyclic hydrocarbon group having 3 to 12 carbon atoms, aromatic hydrocarbon having 6 to 10 carbon atoms A group consisting of a group and a group obtained by combining these groups.
Examples of the alkyl group having 1 to 12 carbon atoms include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, and dodecyl group. .
Examples of the alkoxy group having 1 to 12 carbon atoms include methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, hexyloxy group, octyloxy group, 2-ethylhexyloxy group, nonyloxy group, decyloxy group, undecyloxy group Group, dodecyloxy group and the like.
Examples of the alicyclic hydrocarbon group having 3 to 12 carbon atoms include the following groups. * Is a bond with a ring.

Examples of the aromatic hydrocarbon group having 6 to 10 carbon atoms include a phenyl group and a naphthyl group.
Examples of the combination of these groups include alkoxyalkyl groups having 2 to 24 carbon atoms such as methoxymethyl group, methoxyethyl group, ethoxyethyl group, ethoxymethyl group; methoxymethoxy group, methoxyethoxy group, ethoxymethoxy group, ethoxyethoxy group Examples thereof include C2-C24 alkoxyalkoxy groups such as hydroxymethyl groups and hydroxyethyl groups such as hydroxyethyl groups.
The substituent of ring W ¹ is preferably a hydroxy group, a cyano group or an alkoxy group having 1 to 12 carbon atoms, more preferably a hydroxy group or a cyano group, and further preferably a hydroxy group.

［式（ｗ１−１）〜式（ｗ１−１１）中、
環に含まれる−ＣＨ_２−は、−Ｏ−、−Ｓ−、−ＣＯ−又は−ＳＯ_２−で置換されていてもよく、
環に含まれる少なくとも１つの水素原子は、塩基解離性基で置換される。塩基解離性基で置換された水素原子以外の水素原子は、ヒドロキシ基、炭素数１〜１２のアルキル基、炭素数１〜１２のアルコキシ基、炭素数２〜１３のアルコキシカルボニル基、炭素数２〜１３のアルキルカルボニル基、炭素数２〜１３のアルキルカルボニルオキシ基、炭素数３〜１２の脂環式炭化水素基又は炭素数６〜１０の芳香族炭化水素基で置換されていてもよい。］ The alicyclic hydrocarbon group in the ring W ² may be monocyclic or polycyclic. Specific examples include groups derived from the rings represented by formulas (w1-1) to (w1-11), and alicyclic hydrocarbon groups having 3 to 18 carbon atoms are preferable. A ring represented by (w1-1), a ring represented by formula (w1-2) or a ring represented by formula (w1-3) is preferred.

[In Formula (w1-1)-Formula (w1-11),
—CH ₂ — contained in the ring may be substituted with —O—, —S—, —CO— or —SO ₂ —,
At least one hydrogen atom contained in the ring is substituted with a base dissociable group. A hydrogen atom other than a hydrogen atom substituted with a base dissociable group is a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alkoxycarbonyl group having 2 to 13 carbon atoms, or 2 carbon atoms. It may be substituted with ˜13 alkylcarbonyl group, C2-C13 alkylcarbonyloxy group, C3-C12 alicyclic hydrocarbon group or C6-C10 aromatic hydrocarbon group. ]

Examples of the alkylcarbonyl group having 2 to 13 carbon atoms include an acetyl group, a propionyl group, and a butyryl group.
Examples of the alkylcarbonyloxy group having 2 to 13 carbon atoms include methylcarbonyloxy group, ethylcarbonyloxy group, n-propylcarbonyloxy group, isopropylcarbonyloxy group, n-butylcarbonyloxy group, sec-butylcarbonyloxy group, tert -A butyl carbonyloxy group, a pentyl carbonyloxy group, a hexyl carbonyloxy group, an octyl carbonyloxy group, a 2-ethylhexyl carbonyloxy group, etc. are mentioned.
Examples of the alkoxycarbonyl group having 2 to 13 carbon atoms include methoxycarbonyl group, ethoxycarbonyl group, propoxycarbonyl group, butoxycarbonyl group, pentyloxycarbonyl group, hexyloxycarbonyl group, octyloxycarbonyl group, 2-ethylhexyloxycarbonyl group, Nonyloxycarbonyl group, decyloxycarbonyl group, undecyloxycarbonyl group, dodecyloxycarbonyl group and the like can be mentioned.
As a C1-C12 alkyl group, the same thing as the C1-C12 alkyl group as described in the group A is mentioned.
As a C1-C12 alkoxy group, the same thing as the C1-C12 alkoxy group of the group A is mentioned.
Examples of the alicyclic hydrocarbon group having 3 to 12 carbon atoms include the same alicyclic hydrocarbon groups having 3 to 12 carbon atoms described in Group A.
Examples of the aromatic hydrocarbon group having 6 to 10 carbon atoms include the same aromatic hydrocarbon groups having 6 to 10 carbon atoms as described in Group A.

Ring W ² is preferably an alicyclic hydrocarbon group having 3 to 18 carbon atoms. The ring represented by formula (w1-1), the ring represented by formula (w1-2), and formula (w1) -3) or a ring represented by formula (w1-6) is more preferred, a ring represented by formula (w1-2) or a ring represented by formula (w1-6) Is more preferable.

［式（Ｂａ）中、Ｒ²³は、フッ素原子を有する炭素数１〜６のアルキル基を表す。
式（Ｂｂ）中、Ｒ²⁴は、フッ素原子を有する炭素数１〜６のアルキル基を表す。
Ｒ²⁵及びＲ²⁶は、それぞれ独立に、フッ素原子を有していてもよい炭素数１〜６のアルキル基、水素原子又はフッ素原子を表す。］ At least one hydrogen atom contained in the alicyclic hydrocarbon group represented by ring W ² is substituted with a base dissociable group. The alicyclic hydrocarbon group represented by ring W ² may have a plurality of base dissociable groups, but preferably has one.
The base dissociable group means a group having a leaving group and forming a hydrophilic group (for example, a hydroxy group or a carboxy group) by leaving the leaving group by contact with an alkali.
The base dissociable group is preferably a group represented by the formula (Ba) or a group represented by the formula (Bb).

[In Formula (Ba), R ²³ represents a C 1-6 alkyl group having a fluorine atom.
In the formula (Bb), R ²⁴ represents a C 1-6 alkyl group having a fluorine atom.
R ²⁵ and R ²⁶ each independently represents an alkyl group having 1 to 6 carbon atoms which may have a fluorine atom, a hydrogen atom or a fluorine atom. ]

Examples of the alkyl group having a fluorine atom represented by R ²³ , R ²⁴ , R ²⁵ and R ²⁶ include 1,1,1-trifluoroethyl group, perfluoroethyl group, 1,1,1,2,2 -Pentafluoropropyl group, 2-trifluoromethyl-1,1,1-trifluoroethyl group, perfluoropropyl group, 1,1,1,2,2,3,3-peptafluorobutyl group, perfluorobutyl group 1,1,1,2,2,3,3,4,4-nonafluoropentyl group, perfluoropentyl group, perfluorohexyl group and the like, preferably a C 1-6 perfluoroalkyl group. .
R ²⁵ and R ²⁶ are preferably each independently a hydrogen atom or a fluorine atom.

For example, the group represented by the formula (Ba) is decomposed by the action of an alkali to generate a hydroxy group. The group represented by the formula (Bb) is decomposed by the action of an alkali to generate a carboxy group. The cleavage of the base dissociable group in the salt (aa) can be confirmed according to the method described in JP2013-041269A.
The term “cleavage” means that the bond is broken and divided into a plurality of molecules, and does not include a ring-opening reaction.
As the alkali, tetramethylammonium hydroxide is preferable.

  The anion in the salt (aa) may have a group represented by the formula (aa1), and the cation may have a group represented by the formula (aa). The salt (aa) is preferably a salt composed of an anion having a group represented by the formula (aa1) and a cation, and comprises an anion having a group represented by the formula (aa1) and a sulfonate and a cation. More preferably, it is a salt.

［式（ａａ２）中、
Ｘ^a、Ｘ^b、環Ｗ^１及び環Ｗ^２は、上記と同じ意味を表す。
Ｌ^b1は、炭素数１〜２４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−に置き換わっていてもよく、該飽和炭化水素基に含まれる水素原子は、フッ素原子又はヒドロキシ基で置換されていてもよい。
Ｑ¹及びＱ²は、それぞれ独立に、フッ素原子又は炭素数１〜６のペルフルオロアルキル基を表す。］ The salt (aa) having a group represented by the formula (aa1) is preferably a salt having an anion represented by the formula (aa2).

[In the formula (aa2),
X ^a , X ^b , ring W ¹ and ring W ² represent the same meaning as described above.
L ^b1 represents a divalent saturated hydrocarbon group having 1 to 24 carbon atoms, and —CH ₂ — contained in the saturated hydrocarbon group may be replaced by —O— or —CO—, and The hydrogen atom contained in the hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
Q ¹ and Q ² each independently represents a fluorine atom or a C 1-6 perfluoroalkyl group. ]

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

Examples of the divalent saturated hydrocarbon group represented by L ^b1 include alkanediyl groups, monocyclic or polycyclic divalent alicyclic saturated hydrocarbon groups, and two or more of these groups. May be combined.
Specifically, methylene group, ethylene group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1 , 7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group, dodecane-1,12-diyl group , Tridecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, hexadecane-1,16-diyl group and heptadecane-1,17-diyl group Alkanediyl group;
Ethane-1,1-diyl group, propane-1,1-diyl group, propane-1,2-diyl group, propane-2,2-diyl group, pentane-2,4-diyl group, 2-methylpropane- Branched alkanediyl groups such as 1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl group, 2-methylbutane-1,4-diyl group;
Monocyclic 2 which is a cycloalkanediyl group such as cyclobutane-1,3-diyl group, cyclopentane-1,3-diyl group, cyclohexane-1,4-diyl group, cyclooctane-1,5-diyl group Valent alicyclic saturated hydrocarbon group;
Polycyclic divalent alicyclic saturated hydrocarbon such as norbornane-1,4-diyl group, norbornane-2,5-diyl group, adamantane-1,5-diyl group, adamantane-2,6-diyl group, etc. Groups and the like.

式（ｂ１−１）中、
Ｌ^b2は、単結合又は炭素数１〜２２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水素原子は、フッ素原子に置換されていてもよい。
Ｌ^b3は、単結合又は炭素数１〜２２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水素原子は、フッ素原子又はヒドロキシ基に置換されていてもよく、該飽和炭化水素基に含まれるメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。
ただし、Ｌ^b2とＬ^b3との炭素数合計は、２２以下である。
式（ｂ１−２）中、
Ｌ^b4は、単結合又は炭素数１〜２２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水素原子は、フッ素原子に置換されていてもよい。
Ｌ^b5は、単結合又は炭素数１〜２２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水素原子は、フッ素原子又はヒドロキシ基に置換されていてもよく、該飽和炭化水素基に含まれるメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。
ただし、Ｌ^b4とＬ^b5との炭素数合計は、２２以下である。
式（ｂ１−３）中、
Ｌ^b6は、単結合又は炭素数１〜２３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水素原子は、フッ素原子又はヒドロキシ基に置換されていてもよい。
Ｌ^b7は、単結合又は炭素数１〜２３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水素原子は、フッ素原子又はヒドロキシ基に置換されていてもよく、該飽和炭化水素基に含まれるメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。
ただし、Ｌ^b6とＬ^b7との炭素数合計は、２３以下である。 Examples of the group in which —CH ₂ — contained in the divalent saturated hydrocarbon group represented by L ^b1 is replaced by —O— or —CO— include any of the formulas (b1-1) to (b1-3) The group represented by is mentioned. In the formulas (b1-1) to (b1-3) and the following specific examples, * represents a bond with -W.

In formula (b1-1),
L ^b2 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b3 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, The methylene group contained in the hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
However, the total number of carbon atoms of L ^b2 and L ^b3 is 22 or less.
In formula (b1-2),
L ^b4 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b5 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, The methylene group contained in the hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
However, the total carbon number of L ^b4 and L ^b5 is 22 or less.
In formula (b1-3),
L ^b6 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
L ^b7 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, The methylene group contained in the hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
However, the total carbon number of L ^b6 and L ^b7 is 23 or less.

In formulas (b1-1) to (b1-3), when the methylene group contained in the saturated hydrocarbon group is replaced with an oxygen atom or a carbonyl group, the number of carbons before the replacement is represented by the saturated hydrocarbon group. The number of carbons.
Examples of the divalent saturated hydrocarbon group include the same divalent saturated hydrocarbon groups as those represented by L ^b1 .

L ^b2 is preferably a single bond.
L ^b3 is preferably a divalent saturated hydrocarbon group having 1 to 4 carbon atoms.
L ^b4 is preferably a C 1-8 divalent saturated hydrocarbon group, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b5 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b6 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 4 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b7 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group The methylene group contained in the saturated hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
Among these, a group represented by the formula (b1-1) or the formula (b1-3) is preferable.

式（ｂ１−４）中、
Ｌ^b8は、単結合又は炭素数１〜２２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水素原子は、フッ素原子又はヒドロキシ基に置換されていてもよい。
式（ｂ１−５）中、
Ｌ^b9は、炭素数１〜２０の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれるメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。
Ｌ^b10は、単結合又は炭素数１〜１９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水素原子は、フッ素原子又はヒドロキシ基に置換されていてもよい。
ただし、Ｌ^b9及びＬ^b10の合計炭素数は２０以下である。
式（ｂ１−６）中、
Ｌ^b11は、炭素数１〜２１の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれるメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。
Ｌ^b12は、単結合又は炭素数１〜２０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水素原子は、フッ素原子又はヒドロキシ基に置換されていてもよい。
ただし、Ｌ^b11及びＬ^b12の合計炭素数は２１以下である。
式（ｂ１−７）中、
Ｌ^b13は、炭素数１〜１９の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれるメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。
Ｌ^b14は、単結合又は炭素数１〜１８の２価の飽和炭化水素基を表す。
Ｌ^b15は、単結合又は炭素数１〜１８の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子又はヒドロキシ基に置換されていてもよい。
ただし、Ｌ^b13、Ｌ^b14及びＬ^b15の合計炭素数は１９以下である。
式（ｂ１−８）中、
Ｌ^b16は、炭素数１〜１８の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれるメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。
Ｌ^b17は、炭素数１〜１８の２価の飽和炭化水素基を表す。
Ｌ^b18は、単結合又は炭素数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水素原子は、フッ素原子又はヒドロキシ基に置換されていてもよい。
ただし、Ｌ^b16、Ｌ^b17及びＬ^b18の合計炭素数は１９以下である。 Examples of formula (b1-1) include groups represented by formula (b1-4) to formula (b1-8).

In formula (b1-4),
L ^b8 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
In formula (b1-5),
L ^b9 represents a C 1-20 divalent saturated hydrocarbon group, and the methylene group contained in the saturated hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
L ^b10 represents a single bond or a divalent saturated hydrocarbon group having 1 to 19 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
However, the total carbon number of L ^b9 and L ^b10 is 20 or less.
In formula (b1-6),
L ^b11 represents a divalent saturated hydrocarbon group having 1 to 21 carbon atoms, and the methylene group contained in the saturated hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
L ^b12 represents a single bond or a ^C 1-20 divalent saturated hydrocarbon group, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
However, the total carbon number of L ^b11 and L ^b12 is 21 or less.
In formula (b1-7),
L ^b13 represents a divalent saturated hydrocarbon group having 1 to 19 carbon atoms, and the methylene group contained in the saturated hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
L ^b14 represents a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms.
L ^b15 represents a single bond or a C 1-18 divalent saturated hydrocarbon group, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
However, the total carbon number of L ^b13 , L ^b14 and L ^b15 is 19 or less.
In formula (b1-8),
L ^b16 represents a C 1-18 divalent saturated hydrocarbon group, and the methylene group contained in the saturated hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
L ^b17 represents a divalent saturated hydrocarbon group having 1 to 18 carbon atoms.
L ^b18 represents a single bond or a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
However, the total carbon number of L ^b16 , L ^b17 and L ^b18 is 19 or less.

L ^b8 is preferably a divalent saturated hydrocarbon group having 1 to 4 carbon atoms.
L ^b9 is preferably a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b10 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 19 carbon atoms, and more preferably a single bond or a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b11 is preferably a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b12 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b13 is preferably a divalent saturated hydrocarbon group having 1 to 12 carbon atoms.
L ^b14 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 6 carbon atoms.
L ^b15 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and more preferably a single bond or a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b16 preferably represents a divalent saturated hydrocarbon group having 1 to 12 carbon atoms.
L ^b17 preferably represents a ^C 1-6 divalent saturated hydrocarbon group.
L ^b18 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, and more preferably a single bond or a divalent saturated hydrocarbon group having 1 to 4 carbon atoms.

式（ｂ１−９）中、
Ｌ^b19は、単結合又は炭素数１〜２３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水素原子は、フッ素原子に置換されていてもよい。
Ｌ^b20は、単結合又は炭素数１〜２３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水素原子は、フッ素原子、ヒドロキシ基又はアルキルカルボニルオキシ基に置換されていてもよい。該アルキルカルボニルオキシ基に含まれるメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよく、該アルキルカルボニルオキシ基に含まれる水素原子は、ヒドロキシ基に置換されていてもよい。
ただし、Ｌ^b19及びＬ^b20の合計炭素数は２３以下である。
式（ｂ１−１０）中、
Ｌ^b21は、単結合又は炭素数１〜２１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水素原子は、フッ素原子に置換されていてもよい。
Ｌ^b22は、単結合又は炭素数１〜２１の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれるメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。
Ｌ^b23は、単結合又は炭素数１〜２１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水素原子は、フッ素原子、ヒドロキシ基又はアルキルカルボニルオキシ基に置換されていてもよい。該アルキルカルボニルオキシ基に含まれるメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよく、該アルキルカルボニルオキシ基に含まれる水素原子は、ヒドロキシ基に置換されていてもよい。
ただし、Ｌ^b21、Ｌ^b22及びＬ^b23の合計炭素数は２１以下である。
式（ｂ１−１１）中、
Ｌ^b24は、単結合又は炭素数１〜２０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水素原子は、フッ素原子に置換されていてもよい。
Ｌ^b25は、炭素数１〜２１の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれるメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。
Ｌ^b26は、単結合又は炭素数１〜２０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水素原子は、フッ素原子、ヒドロキシ基又はアルキルカルボニルオキシ基に置換されていてもよい。該アルキルカルボニルオキシ基に含まれるメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよく、該アルキルカルボニルオキシ基に含まれる水素原子は、ヒドロキシ基に置換されていてもよい。
ただし、Ｌ^b24、Ｌ^b25及びＬ^b26の合計炭素数は２１以下である。 Examples of formula (b1-3) include groups represented by formula (b1-9) to formula (b1-11), respectively.

In formula (b1-9),
L ^b19 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b20 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group is substituted with a fluorine atom, a hydroxy group or an alkylcarbonyloxy group. Also good. The methylene group contained in the alkylcarbonyloxy group may be replaced with an oxygen atom or a carbonyl group, and the hydrogen atom contained in the alkylcarbonyloxy group may be substituted with a hydroxy group.
However, the total carbon number of L ^b19 and L ^b20 is 23 or less.
In formula (b1-10),
L ^b21 represents a single bond or a divalent saturated hydrocarbon group having 1 to ²¹ carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b22 represents a single bond or a divalent saturated hydrocarbon group having 1 to 21 carbon atoms, and the methylene group contained in the saturated hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
L ^b23 represents a single bond or a divalent saturated hydrocarbon group having 1 to ²¹ carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group is substituted with a fluorine atom, a hydroxy group or an alkylcarbonyloxy group. Also good. The methylene group contained in the alkylcarbonyloxy group may be replaced with an oxygen atom or a carbonyl group, and the hydrogen atom contained in the alkylcarbonyloxy group may be substituted with a hydroxy group.
However, the total carbon number of L ^b21 , L ^b22 and L ^b23 is 21 or less.
In formula (b1-11),
L ^b24 represents a single bond or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b25 represents a divalent saturated hydrocarbon group having 1 to 21 carbon atoms, and the methylene group contained in the saturated hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
L ^b26 represents a single bond or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group is substituted with a fluorine atom, a hydroxy group or an alkylcarbonyloxy group. Also good. The methylene group contained in the alkylcarbonyloxy group may be replaced with an oxygen atom or a carbonyl group, and the hydrogen atom contained in the alkylcarbonyloxy group may be substituted with a hydroxy group.
However, L ^b24, the total number of carbon atoms of L ^b25 and L ^b26 is 21 or less.

  In the formulas (b1-10) and (b1-11), when a hydrogen atom contained in the saturated hydrocarbon group is substituted with an alkylcarbonyloxy group, the number of carbon atoms in the alkylcarbonyloxy group, in the ester bond Including the number of CO and O, the carbon number of the saturated hydrocarbon group.

  Examples of the alkylcarbonyloxy group include an acetyloxy group, a propionyloxy group, a butyryloxy group, a cyclohexylcarbonyloxy group, and an adamantylcarbonyloxy group.

Of the groups represented by formula (b1-1), examples of the group represented by formula (b1-4) include the following.

Of the groups represented by the formula (b1-1), examples of the group represented by the formula (b1-5) include the following.

Of the groups represented by formula (b1-1), examples of the group represented by formula (b1-6) include the following.

Of the groups represented by the formula (b1-1), examples of the group represented by the formula (b1-7) include the following.

Of the groups represented by the formula (b1-1), examples of the group represented by the formula (b1-8) include the following.

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

Of the groups represented by formula (b1-3), examples of the group represented by formula (b1-9) include the following.

Of the groups represented by the formula (b1-3), examples of the group represented by the formula (b1-10) include the following.

Of the groups represented by formula (b1-3), examples of the group represented by formula (b1-11) include the following.

As L ^b1 , * 1-CO—O— (CH ₂ ) _t — (t represents an integer of 0 to 6. * 1 represents a bond with —C (Q ¹ ) (Q ² ) —. Represents a hand).

Examples of the anion represented by the formula (aa2) include the following anions.

The cation in the salt (aa) is preferably an organic cation. Examples of the organic cation include an organic onium cation, an organic sulfonium cation, an organic iodonium cation, an organic ammonium cation, a benzothiazolium cation, and an organic phosphonium cation. Among these, an organic sulfonium cation and an organic iodonium cation are preferable, and an arylsulfonium cation is more preferable.
Among these, a cation represented by any one of the formulas (b2-1) to (b2-4) (hereinafter may be referred to as “cation (b2-1)” or the like depending on the formula number) is preferable.

式（ｂ２−１）〜式（ｂ２−４）において、
Ｒ^b4〜Ｒ^b6は、それぞれ独立に、炭素数１〜３０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を表し、該脂肪族炭化水素基に含まれる水素原子は、ヒドロキシ基、炭素数１〜１２のアルコキシ基、炭素数３〜１２の脂環式炭化水素基又は炭素数６〜１８の芳香族炭化水素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水素原子は、ハロゲン原子、炭素数１〜１８の脂肪族炭化水素基、炭素数２〜４のアルキルカルボニル基又はグリシジルオキシ基で置換されていてもよく、該芳香族炭化水素基に含まれる水素原子は、ハロゲン原子、ヒドロキシ基又は炭素数１〜１２のアルコキシ基で置換されていてもよい。
Ｒ^b4とＲ^b5とは、一緒になってそれらが結合する硫黄原子を含む環を形成してもよく、該環に含まれるメチレン基は、酸素原子、スルフィニル基又はカルボニル基に置き換わってもよい。

In formula (b2-1) to formula (b2-4),
R ^{b4 to} R ^b6 each independently represents an aliphatic hydrocarbon group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 36 carbon atoms, or an aromatic hydrocarbon group having 6 to 36 carbon atoms, The hydrogen atom contained in the aliphatic hydrocarbon group is a hydroxy group, an alkoxy group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms. The hydrogen atom contained in the alicyclic hydrocarbon group which may be substituted is a halogen atom, an aliphatic hydrocarbon group having 1 to 18 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms or a glycidyloxy group. The hydrogen atom contained in the aromatic hydrocarbon group may be substituted with a halogen atom, a hydroxy group, or an alkoxy group having 1 to 12 carbon atoms.
R ^b4 and R ^b5 together may form a ring containing a sulfur atom to which they are bonded, and the methylene group contained in the ring may be replaced with an oxygen atom, a sulfinyl group or a carbonyl group. .

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

R ^b9 and R ^b10 each independently represent an aliphatic hydrocarbon group having 1 to 36 carbon atoms or an alicyclic hydrocarbon group having 3 to 36 carbon atoms.
R ^b9 and R ^b10 together may form a ring containing a sulfur atom to which they are bonded, and the methylene group contained in the ring may be replaced with an oxygen atom, a sulfinyl group or a carbonyl group. .
R ^b11 represents a hydrogen atom, 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 18 carbon atoms.
R ^b12 represents an aliphatic hydrocarbon group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms, and is included in the aliphatic hydrocarbon The hydrogen atom may be substituted with an aromatic hydrocarbon group having 6 to 18 carbon atoms, and the hydrogen atom contained in the aromatic hydrocarbon group is an alkoxy group having 1 to 12 carbon atoms or 1 to 1 carbon atoms. It may be substituted with 12 alkylcarbonyloxy groups.
R ^b11 and R ^b12 may together form a ring containing —CH—CO— to which they are bonded, and the methylene group contained in the ring is bonded to an oxygen atom, a sulfinyl group or a carbonyl group. It may be replaced.

R ^{b13 to} R ^b18 each independently represent a hydroxy group, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.
L ^b31 represents a sulfur atom or an oxygen atom.
o2, p2, s2, and t2 each independently represents an integer of 0 to 5.
q2 and r2 each independently represents an integer of 0 to 4.
u2 represents 0 or 1.
When o2 is 2 or more, multiple R ^b13 are the same or different, when p2 is 2 or more, multiple R ^b14 are the same or different, and when q2 is 2 or more, multiple R ^b15 are the same or different , When r2 is 2 or more, a plurality of R ^b16 are the same or different, when s2 is 2 or more, a plurality of R ^b17 are the same or different, and when t2 is 2 or more, a plurality of R ^b18 are the same or different Different.

特に、Ｒ^b9〜Ｒ^b12の脂環式炭化水素基は、好ましくは炭素数３〜１８、より好ましくは炭素数４〜１２である。 Examples of the aliphatic hydrocarbon group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, and n-octyl group. Group and an alkyl group of 2-ethylhexyl group. In particular, the aliphatic hydrocarbon group represented by R ^{b9 to} R ^b12 preferably has 1 to 12 carbon atoms.
The alicyclic hydrocarbon group may be monocyclic or polycyclic, and the monocyclic alicyclic hydrocarbon group may be a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cyclo group. Examples thereof include cycloalkyl groups such as heptyl group, cyclooctyl group and cyclodecyl group. Examples of the polycyclic alicyclic hydrocarbon group include decahydronaphthyl group, adamantyl group, norbornyl group, and the following groups.

In particular, the alicyclic hydrocarbon group of R ^{b9 to} R ^b12 preferably has 3 to 18 carbon atoms, more preferably 4 to 12 carbon atoms.

  Examples of the alicyclic hydrocarbon group in which a hydrogen atom is substituted with an aliphatic hydrocarbon group include a methylcyclohexyl group, a dimethylcyclohexyl group, a 2-alkyladamantan-2-yl group, a methylnorbornyl group, and an isobornyl group. Is mentioned. In the alicyclic hydrocarbon group in which a hydrogen atom is substituted with an aliphatic hydrocarbon group, the total number of carbon atoms of the alicyclic hydrocarbon group and the aliphatic hydrocarbon group is preferably 20 or less.

As aromatic hydrocarbon group, phenyl group, tolyl group, xylyl group, cumenyl group, mesityl group, p-ethylphenyl group, p-tert-butylphenyl group, p-cyclohexylphenyl group, p-adamantylphenyl group , Aryl groups such as a biphenylyl group, a naphthyl group, a phenanthryl group, a 2,6-diethylphenyl group, and a 2-methyl-6-ethylphenyl group.
When the aromatic hydrocarbon group includes an aliphatic hydrocarbon group or an alicyclic hydrocarbon group, the aliphatic hydrocarbon group having 1 to 18 carbon atoms and the alicyclic hydrocarbon having 3 to 18 carbon atoms Groups are preferred.
Examples of the aromatic hydrocarbon group in which a hydrogen atom is substituted with an alkoxy group include a p-methoxyphenyl group.
Examples of the aliphatic hydrocarbon group in which a hydrogen atom is substituted with an aromatic hydrocarbon group include aralkyl groups such as a benzyl group, a phenethyl group, a phenylpropyl group, a trityl group, a naphthylmethyl group, and a naphthylethyl group.

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

The ring containing a sulfur atom formed by combining R ^b4 and R ^b5 may be any of monocyclic, polycyclic, aromatic, non-aromatic, saturated and unsaturated rings. . Examples of the ring include a ring having 3 to 18 carbon atoms, and a ring having 4 to 18 carbon atoms is preferable. Moreover, the ring containing a sulfur atom includes a 3-membered ring to a 12-membered ring, preferably a 3-membered ring to a 7-membered ring, and examples thereof include the following rings.

The ring formed by combining R ^b9 and R ^b10 may be any of monocyclic, polycyclic, aromatic, non-aromatic, saturated and unsaturated rings. This ring includes a 3-membered ring to a 12-membered ring, preferably a 3-membered ring to a 7-membered ring. Examples thereof include a thiolane-1-ium ring (tetrahydrothiophenium ring), a thian-1-ium ring, and a 1,4-oxathian-4-ium ring.
The ring formed by ^combining R ^b11 and R ^b12 may be any of monocyclic, polycyclic, aromatic, non-aromatic, saturated and unsaturated rings. This ring includes a 3-membered ring to a 12-membered ring, preferably a 3-membered ring to a 7-membered ring. Examples thereof include an oxocycloheptane ring, an oxocyclohexane ring, an oxonorbornane ring, and an oxoadamantane ring.

  Among the cation (b2-1) to cation (b2-4), the cation (b2-1) is preferable.

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

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

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

Examples of the cation (b2-4) include the following cations.

The salt (aa) can be arbitrarily combined with the anions and cations described above. These anions and cations can be arbitrarily combined.
Examples of the salt (aa) include the salts described in Tables 1 to 4.
The salt (aa-1) in Table 1 represents the following salt.

  Especially, salt (aa) is salt (I-1), salt (I-3), salt (I-5), salt (I-6), salt (I-9), salt (I-10). , Salt (I-21), salt (I-23), salt (I-25), salt (I-26), salt (I-29), salt (I-30), salt (I-41), Salt (I-43), salt (I-45), salt (I-46), salt (I-49), salt (I-50), salt (I-61), salt (I-63), salt (I-65), salt (I-66), salt (I-69), salt (I-70), salt (I-81), salt (I-83), salt (I-85), salt ( I-86), salt (I-89), salt (I-90), salt (I-101), salt (I-103), salt (I-105), salt (I-106), salt (I -109), salt (I-110), salt (I-121), salt (I-123), salt (I-125), salt (I-1 6), salt (I-129) and salts (I-130) are preferred.

（式中、Ｘ^ａ、Ｘ^ｂ、Ｌ^ｂ１、Ｑ^１、Ｑ^２、環Ｗ^１、環Ｗ^２、Ｒ²³及びＺ^＋は上記と同じ意味を表す。）
溶媒としては、クロロホルム、アセトニトリル等が挙げられる。
塩基触媒としては、Ｎ−メチルピロリジン等が挙げられる。 <Method for producing salt (aa)>
A salt (I1) composed of an anion represented by the formula (aa2) having a group represented by the formula (Ba) and an organic cation (Z ⁺ ) having a base labile group is represented by the formula (I1-a). Can be produced by reacting the salt represented by the formula (I1-b) with a basic catalyst in a solvent.

(In the formula, X ^a , X ^b , L ^b1 , Q ¹ , Q ² , ring W ¹ , ring W ² , R ²³ and Z ⁺ represent the same meaning as described above.)
Examples of the solvent include chloroform and acetonitrile.
Examples of the base catalyst include N-methylpyrrolidine.

式（Ｉ１−ｂ）で表される化合物としては、ヘプタフルオロブチリルクロリドなどが挙げられる。 Examples of the salt represented by the formula (I1-a) include a compound represented by the following formula.

Examples of the compound represented by the formula (I1-b) include heptafluorobutyryl chloride.

（式中、Ｘ^ａ、Ｘ^ｂ、Ｌ^ｂ１、Ｑ^１、Ｑ^２、環Ｗ^１、環Ｗ^２、Ｒ²⁴、Ｒ²⁵、Ｒ²⁶及びＺ^＋は上記と同じ意味を表す。）
溶媒としては、クロロホルム、アセトニトリル等が挙げられる。 A salt (I2) composed of an anion represented by formula (aa2) having a group represented by formula (Bb) and an organic cation (Z ⁺ ), wherein the base labile group is represented by formula (I2-a). It can manufacture by making it react with the compound represented by a formula (I2-b), after making the salt and carbonyldiimidazole react in a solvent.

(Wherein, X ^a , X ^b , L ^b1 , Q ¹ , Q ² , ring W ¹ , ring W ² , R ²⁴ , R ²⁵ , R ²⁶ and Z ⁺ represent the same meaning as described above)
Examples of the solvent include chloroform and acetonitrile.

式（Ｉ２−ｂ）で表される化合物としては、下記式で表される化合物等が挙げられ、市場より容易に入手できる。

Examples of the salt represented by the formula (I2-a) include compounds represented by the following formula, and the compounds can be synthesized with reference to JP-A No. 2014-189534.

Examples of the compound represented by the formula (I2-b) include compounds represented by the following formulas, and are easily available from the market.

[Resist composition]
The resist composition of the present invention contains a resin having an acid labile group (hereinafter sometimes referred to as “resin (A)”) and a salt (aa). Here, the “acid labile group” has a leaving group, the leaving group is eliminated by contact with an acid, and the structural unit has a hydrophilic group (for example, a hydroxy group or a carboxy group). Means a group that converts to
The resist composition is further an acid generator known in the resist field (hereinafter sometimes referred to as an acid generator (B)). A quencher (hereinafter sometimes referred to as “quencher (C)”) and a solvent (hereinafter also referred to as “solvent (E)”) may be contained.

<Acid generator (B)>
The acid generator (B) may be either nonionic or ionic. Nonionic acid generators include organic halides, sulfonate esters (for example, 2-nitrobenzyl ester, aromatic sulfonate, oxime sulfonate, N-sulfonyloxyimide, N-sulfonyloxyimide, sulfonyloxyketone, diazonaphthoquinone 4). -Sulfonates), sulfones (e.g. disulfone, ketosulfone, sulfonyldiazomethane) and the like. Examples of the ionic acid generator include ionic acid generators comprising a combination of a known cation and a known anion, and onium salts containing an onium cation (eg, diazonium salts, phosphonium salts, sulfonium salts, iodonium salts) are representative Is. Examples of the anion of the onium salt include a sulfonate anion, a sulfonylimide anion, and a sulfonylmethide anion.

  As the acid generator (B), JP-A-63-26653, JP-A-55-164824, JP-A-62-69263, JP-A-63-146038, JP-A-63-163452, Kaisho 62-153853, JP 63-146029, U.S. Pat. No. 3,779,778, U.S. Pat. No. 3,849,137, German Patent 3914407, European Patent 126,712, etc. And the acid generators described in JP2013-68914A, JP2013-3155A, JP2013-11905A, and the like.

［式（Ｂ１）中、
Ｑ^１１及びＱ^１２は、それぞれ独立に、フッ素原子又は炭素数１〜６のペルフルオロアルキル基を表す。
Ｌ^Ｂ１は、炭素数１〜２４の２価の飽和炭化水素基を表し、該２価の飽和炭化水素基に含まれる−ＣＨ_２−は−Ｏ−又は−ＣＯ−に置き換わっていてもよく、該２価の飽和炭化水素基に含まれる水素原子はフッ素原子又はヒドロキシ基で置換されていてもよい。
Ｙは、置換基を有していてもよいメチル基又は置換基を有していてもよい炭素数３〜１８の脂環式炭化水素基を表し、該脂環式炭化水素基に含まれる−ＣＨ_２−は、−Ｏ−、−ＳＯ_２−又は−ＣＯ−に置き換わっていてもよい。
Ｚ^＋は、有機カチオンを表す。］ Examples of the acid generator (B) include organic sulfonates, preferably fluorine-containing acid generators, more preferably an acid generator represented by the formula (B1) (hereinafter referred to as “acid generator ( B1) ”may be mentioned).

[In the formula (B1),
Q ¹¹ and Q ¹² each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group.
L ^B1 represents a divalent saturated hydrocarbon group having 1 to 24 carbon atoms, and —CH ₂ — contained in the divalent saturated hydrocarbon group may be replaced by —O— or —CO—, The hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
Y represents an optionally substituted methyl group or an optionally substituted alicyclic hydrocarbon group having 3 to 18 carbon atoms, and is included in the alicyclic hydrocarbon group − CH ₂ — may be replaced by —O—, —SO ₂ — or —CO—.
Z ⁺ represents an organic cation. ]

Examples of the perfluoroalkyl group for Q ¹¹ and Q ¹² include the same groups as those described for the perfluoroalkyl group represented by Q ¹ and Q ² .
Q ¹¹ and Q ¹² are each independently preferably a fluorine atom or a trifluoromethyl group, and more preferably a fluorine atom. More preferably, Q ¹¹ and Q ¹² are both fluorine atoms.

Examples of the divalent saturated hydrocarbon group represented by L ^B1 include the same divalent saturated hydrocarbon groups represented by L ^b1 .
The group in which —CH ₂ — contained in the divalent saturated hydrocarbon group represented by L ^B1 is replaced by —O— or —CO— is contained in the divalent saturated hydrocarbon group represented by L ^b1. And the same group in which —CH ₂ — is replaced by —O— or —CO—. Specific examples include groups represented by the above-described formulas (b1-1) to (b1-3). In addition, when L ^B1 is a group represented by formula (b1-1) to formula (b1-3), * in the group represented by formula (b1-1) to formula (b1-3) is Y and Represents the bond hand.
L ^B1 is preferably any one of groups represented by formula (b1-1) to formula (b1-3), * 2-CO—O— (CH ₂ ) _t1 —, * 2- (CH _{2) t2 -O-CO- (.} t1 is .t2 representing an integer of 0 to 6 represents an integer of any of 1 to 6 * ^{2, -C (Q 11) (Q} 12) - It is more preferable that the bond is

The monovalent alicyclic hydrocarbon group represented by Y may be monocyclic, polycyclic or spirocyclic. Specific examples include groups represented by formula (Y1) to formula (Y38).
When —CH ₂ — contained in the alicyclic hydrocarbon group represented by Y is replaced by —O—, —SO ₂ — or —CO—, the number may be one or two or more. .

  Among them, a group represented by any one of Formula (Y1) to Formula (Y20), Formula (Y30), or Formula (Y31) is preferable, and Formula (Y11), Formula (Y15), Formula (Y Y16), a group represented by the formula (Y19), a formula (Y30) or a formula (Y31) can be mentioned, and a group represented by the formula (Y11), the formula (Y15) or the formula (Y30) is more preferable. It is done.

As a substituent of the alicyclic hydrocarbon group of Y, a halogen atom, a hydroxy group, an alkyl group having 1 to 12 carbon atoms which may have a hydroxy group, an alicyclic hydrocarbon group having 3 to 16 carbon atoms , An alkoxy group having 1 to 12 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, an aralkyl group having 7 to 21 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms, a glycidyloxy group, or — (CH ₂ ). _{ja ′} —O—CO—R ^{b1 ′} group (wherein R ^{b1 ′} is an alkyl group having 1 to 16 carbon atoms, an alicyclic hydrocarbon group having 3 to 16 carbon atoms, or an aromatic group having 6 to 18 carbon atoms) Represents a hydrocarbon group, and ja ′ represents an integer of 0 to 4).

Examples of the alkyl group having a hydroxy group include a hydroxymethyl group and a hydroxyethyl group.
Examples of the alkoxy group include methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, hexyloxy group, heptyloxy group, octyloxy group, decyloxy group and dodecyloxy group.
Aromatic hydrocarbon groups include phenyl, naphthyl, anthryl, p-methylphenyl, p-tert-butylphenyl, p-adamantylphenyl; tolyl, xylyl, cumenyl, mesityl, biphenyl Groups, phenanthryl groups, 2,6-diethylphenyl groups, aryl groups such as 2-methyl-6-ethylphenyl, and the like.
Examples of the aralkyl group include benzyl group, phenethyl group, phenylpropyl group, naphthylmethyl group, and naphthylethyl group.
Examples of the alkylcarbonyl group include an acetyl group, a propionyl group, and a butyryl group.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

Examples of Y include the following.

Y is preferably a monovalent alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent, and more preferably an adamantyl group which may have a substituent (these —CH ₂ — constituting the group may be replaced by —O—, —SO ₂ — or —CO—. More preferably, adamantyl group, hydroxyadamantyl group or oxoadamantyl group or It is a group.

  Examples of the anion of the salt represented by the formula (B1) include formulas (B1-A-1) to (B1-A-54). Anions represented by formula (B1-A-1) to formula (B1-A-54) [hereinafter referred to as “anions (B1-A-1)” depending on the formula number, etc.). ] Is preferable, Formula (B1-A-1)-Formula (B1-A-4), Formula (B1-A-9), Formula (B1-A-10), Formula (B1-A-24)-Formula It is represented by any one of (B1-A-33), formula (IA-36) to formula (IA-40), formula (B1-A-47) to formula (B1-A-55). An anion is more preferable.

Here, R ^{i2 to} R ⁱ⁷ are, for example, an alkyl group having 1 to 4 carbon atoms, preferably a methyl group or an ethyl group.
R ⁱ⁸ is, for example, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, preferably an alkyl group having 1 to 4 carbon atoms, an alicyclic hydrocarbon group having 5 to 12 carbon atoms, or a combination thereof. It is a group to be formed, more preferably a methyl group, an ethyl group, a cyclohexyl group or an adamantyl group.
L ⁴⁴ is a single bond or an alkanediyl group having 1 to 4 carbon atoms.
Q ¹¹ and Q ¹² are the same as described above.

Examples of the anion in the salt represented by the formula (B1) include anions represented by the formulas (B1a-1) to (B1a-34).

  Especially, it is represented by any one of formula (B1a-1) to formula (B1a-3) and formula (B1a-7) to formula (B1a-19), formula (B1a-22) to formula (B1a-34). An anion is preferred.

Examples of the organic cation for Z ⁺ include the same organic cation as exemplified for the organic cation in the salt (aa).

Specific examples of the acid generator (B) include those represented by the formula (B1-1) to the formula (B1-48), respectively. Among them, the formula (B1-1) containing an arylsulfonium cation Formula (B1-3), Formula (B1-5) to Formula (B1-7), Formula (B1-11) to Formula (B1-14), Formula (B1-17), Formula (B1-20) to Formula Particularly preferred are those represented by (B1-26), formula (B1-29), and formula (B1-31) to formula (B1-48).

The salt (aa) can act as an acid generator in the resist composition. Two or more salts (aa) may be contained.
The content of the salt (aa) is preferably 1 to 40 parts by mass and more preferably 2 to 35 parts by mass with respect to 100 parts by mass of the resin (A).
The acid generator (B) may contain 2 or more types.
The content of the acid generator (B) is preferably 1 to 40 parts by mass and more preferably 3 to 35 parts by mass with respect to 100 parts by mass of the resin (A).
In the resist composition, the content of the salt (aa) and the acid generator (B) is preferably 1.5% by mass or more (more preferably 3% by mass or more), preferably with respect to the resin (A). 40% by mass or less (more preferably 35% by mass or less).
When both the salt (aa) and the acid generator (B) are contained, it is preferable that the content ratio of the acid generator (B) is large.

<Resin (A)>
The resin (A) has a structural unit having an acid labile group (hereinafter sometimes referred to as “structural unit (a1)”). The resin (A) preferably further contains a structural unit other than the structural unit (a1). The structural unit other than the structural unit (a1) includes a structural unit having no acid labile group (hereinafter sometimes referred to as “structural unit (s)”), a structural unit (a1), and a structural unit other than the structural unit (s). Examples thereof include a structural unit (hereinafter sometimes referred to as “structural unit (t)”) and other structural units derived from monomers known in the art.

［式（１）中、Ｒ^a1〜Ｒ^a3は、それぞれ独立に、炭素数１〜８のアルキル基、炭素数３〜２０の脂環式炭化水素基又はこれらを組み合わせた基を表すか、Ｒ^a1及びＲ^a2は互いに結合してそれらが結合する炭素原子とともに炭素数３〜２０の２価の脂環式炭化水素基を形成する。
ｎａは、０又は１を表す。
＊は酸素原子又は硫黄原子との結合手を表す。］

［式（２）中、Ｒ^a1’及びＲ^a2’は、それぞれ独立に、水素原子又は炭素数１〜１２の炭化水素基を表し、Ｒ^a3’は、炭素数１〜２０の炭化水素基を表すか、Ｒ^a2’及びＲ^a3’は互いに結合してそれらが結合する炭素原子及びＸとともに炭素数３〜２０の２価の複素環基を形成し、該炭化水素基及び該２価の複素環基に含まれる−ＣＨ₂−は、−Ｏ−又は−Ｓ−で置き換わってもよい。
Ｘは、酸素原子又は硫黄原子を表す。
＊は酸素原子又は硫黄原子との結合手を表す。］ <Structural unit (a1)>
The structural unit (a1) is derived from a monomer having an acid labile group (hereinafter sometimes referred to as “monomer (a1)”).
The leaving group of the acid labile group contained in the resin (A) is preferably a group represented by the formula (1) and / or a group represented by the formula (2).

[In the formula (1), R ^{a1 to} R ^a3 each independently represents an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or a combination of these, or R ^a1 and R ^a2 are bonded to each other to form a divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms together with the carbon atom to which they are bonded.
na represents 0 or 1.
* Represents a bond with an oxygen atom or a sulfur atom. ]

[In Formula (2), R ^{a1 ′} and R ^{a2 ′} each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, and R ^{a3 ′} represents a hydrocarbon group having 1 to 20 carbon atoms. R ^{a2 ′} and R ^{a3 ′} are bonded to each other to form a divalent heterocyclic group having 3 to 20 carbon atoms together with the carbon atom to which they are bonded and X, and the hydrocarbon group and the divalent —CH ₂ — contained in the ring group may be replaced by —O— or —S—.
X represents an oxygen atom or a sulfur atom.
* Represents a bond with an oxygen atom or a sulfur atom. ]

アルキル基と脂環式炭化水素基とを組み合わせた基としては、例えば、メチルシクロヘキシル基、ジメチルシクロへキシル基、メチルノルボルニル基、シクロヘキシルメチル基、アダマンチルメチル基、ノルボルニルエチル基等が挙げられる。
ｎａは、好ましくは０である。 ^Examples of the alkyl group represented by R ^{a1 to} R ^a3 include a methyl group, an ethyl group, a propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, and an n-octyl group.
The alicyclic hydrocarbon group for R ^{a1 to} R ^a3 may be monocyclic or polycyclic. Examples of the monocyclic alicyclic hydrocarbon group include cycloalkyl groups such as a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. Examples of the polycyclic alicyclic hydrocarbon group include decahydronaphthyl group, adamantyl group, norbornyl group, and the following groups (* represents a bond). The alicyclic hydrocarbon group of R ^{a1 to} R ^a3 is preferably an alicyclic hydrocarbon group having 3 to 16 carbon atoms.

Examples of the group obtained by combining an alkyl group and an alicyclic hydrocarbon group include a methylcyclohexyl group, a dimethylcyclohexyl group, a methylnorbornyl group, a cyclohexylmethyl group, an adamantylmethyl group, and a norbornylethyl group. Can be mentioned.
na is preferably 0.

Examples of —C (R ^a1 ) (R ^a2 ) (R ^a3 ) when R ^a1 and R ^a2 are bonded to each other to form a divalent alicyclic hydrocarbon group include the following groups. The divalent alicyclic hydrocarbon group preferably has 3 to 12 carbon atoms. * Represents a bond with -O-.

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

Ｒ^a1’及びＲ^a2’のうち、少なくとも１つは水素原子であることが好ましい。 Examples of the hydrocarbon group of R ^{a1 ′ to} R ^{a3 ′} include an alkyl group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and a group formed by combining these.
Examples of the alkyl group and alicyclic hydrocarbon group are the same as those described above.
Aromatic hydrocarbon groups include phenyl, naphthyl, anthryl, p-methylphenyl, p-tert-butylphenyl, p-adamantylphenyl, tolyl, xylyl, cumenyl, mesityl, biphenyl Groups, phenanthryl groups, 2,6-diethylphenyl groups, aryl groups such as 2-methyl-6-ethylphenyl, and the like.
^{Examples of the} divalent heterocyclic group formed together with the carbon atom to which R ^{a2 ′} and R ^{a3 ′} are bonded to each other and X are bonded to each other include the following groups. * Represents a bond.

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

Specific examples of the group represented by the formula (2) include the following groups. * Represents a bond.

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

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

  As a structural unit derived from a (meth) acrylic monomer having a group represented by the formula (1), a structural unit represented by the formula (a1-0) is preferably represented by the formula (a1-1). The structural unit represented by a structural unit or a formula (a1-2) is mentioned. These may be used alone or in combination of two or more. In this specification, the structural unit represented by formula (a1-0), the structural unit represented by formula (a1-1), and the structural unit represented by formula (a1-2) are each represented by structural unit (a1). -0), structural unit (a1-1), and structural unit (a1-2).

［式（ａ１−０）中、
Ｌ^a01は、酸素原子又は^＊−Ｏ−（ＣＨ₂）_k01−ＣＯ−Ｏ−を表し、ｋ０１は１〜７のいずれかの整数を表し、＊はカルボニル基との結合手を表す。
Ｒ^a01は、水素原子又はメチル基を表す。
Ｒ^a02、Ｒ^a03及びＲ^a04は、それぞれ独立に、炭素数１〜８のアルキル基、炭素数３〜１８の脂環式炭化水素基又はこれらを組み合わせた基を表す。］

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

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

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

L ^a01 is preferably an oxygen atom or ^* —O— (CH ₂ ) _k01 —CO—O— (where k01 is preferably an integer of 1 to 4, more preferably 1. ), More preferably an oxygen atom.
Examples of the alkyl group of R ^a02 , R ^a03, and R ^a04 , the alicyclic hydrocarbon group, and a group obtained by combining these include the same groups as those described for R ^{a1 to} R ^a3 in formula (1).
The alkyl group for R ^a02 , R ^a03 and R ^a04 preferably has 6 or less carbon atoms.
The alicyclic hydrocarbon group ^{represented by} R ^a02 , R ^a03 and R ^a04 preferably has 8 or less carbon atoms, more preferably 6 or less.
The group combining the alkyl group and the alicyclic hydrocarbon group preferably has a total carbon number of 18 or less, combining the alkyl group and the alicyclic hydrocarbon group. Examples of such groups include a methylcyclohexyl group, a dimethylcyclohexyl group, a methylnorbornyl group, a methyladamantyl group, a cyclohexylmethyl group, a methylcyclohexylmethyl group, an adamantylmethyl group, and a norbornylmethyl group. It is done.
R ^a02 and R ^a03 are preferably an alkyl group having 1 to 6 carbon atoms, more preferably a methyl group or an ethyl group.
R ^a04 is preferably an alkyl group having 1 to 6 carbon atoms or an alicyclic hydrocarbon group having 5 to 12 carbon atoms, and more preferably a methyl group, an ethyl group, a cyclohexyl group, or an adamantyl group.

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

As the structural unit (a1-0), for example, a structural unit represented by any one of formulas (a1-0-1) to (a1-0-12) is preferable, and formula (a1-0-1) to The structural unit represented by any one of formulas (a1-0-10) is more preferable.

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

Examples of the structural unit (a1-1) include structural units derived from monomers described in JP 2010-204646 A. Among these, a monomer represented by any one of formula (a1-1-1) to formula (a1-1-8) is preferable, and any one of formula (a1-1-1) to formula (a1-1-4) is preferable. The monomer represented by is more preferable.

The structural unit (a1-2) is preferably a structural unit represented by any one of formulas (a1-2-1) to (a1-2-12), and includes formula (a1-2-3) and formula (a1). -2-4), structural units represented by formula (a1-2-9) and formula (a1-2-10) are more preferred, and formula (a1-2-3) and formula (a1-2-9) Is more preferable.

  When the resin (A) includes the structural unit (a1-0) and / or the structural unit (a1-1) and / or the structural unit (a1-2), the total content thereof is the total structure of the resin (A). It is 10-95 mol% normally with respect to a unit, Preferably it is 15-90 mol%, More preferably, it is 20-85 mol%.

式（ａ１−５）中、
Ｒ^a8は、ハロゲン原子を有していてもよい炭素数１〜６のアルキル基、水素原子又はハロゲン原子を表す。
Ｚ^a1は、単結合又は＊−（ＣＨ₂）_h3−ＣＯ−Ｌ⁵⁴−を表し、ｈ３は１〜４のいずれかの整数を表し、＊は、Ｌ⁵¹との結合手を表す。
Ｌ⁵¹、Ｌ⁵²、Ｌ⁵³及びＬ⁵⁴は、それぞれ独立に、−Ｏ−又は−Ｓ−を表す。
ｓ１は、１〜３のいずれかの整数を表す。
ｓ１’は、０〜３のいずれかの整数を表す。 As a structural unit derived from a (meth) acrylic monomer having a group represented by the formula (2), a structural unit represented by the formula (a1-5) (hereinafter referred to as “structural unit (a1-5)”) Is also included).

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

Examples of the halogen atom include a fluorine atom and a chlorine atom, and a fluorine atom is preferable.
Examples of the alkyl group having 1 to 6 carbon atoms which may have a halogen atom include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, fluoromethyl and trifluoro A methyl group is mentioned.
In formula (a1-5), R ^a8 is preferably a hydrogen atom, a methyl group or a trifluoromethyl group.
L ⁵¹ is preferably an oxygen atom.
Of L ⁵² and L ⁵³ , one is preferably —O— and the other is preferably —S—.
s1 is preferably 1.
s1 ′ is preferably an integer of 0 to 2.
Z ^a1 is preferably a single bond or * —CH ₂ —CO—O—.

As a monomer which introduce | transduces structural unit (a1-5), the monomer described in Unexamined-Japanese-Patent No. 2010-61117 is mentioned, for example. Among these, structural units each represented by formula (a1-5-1) to formula (a1-5-4) are preferable, and are represented by formula (a1-5-1) or formula (a1-5-2). A structural unit is more preferable.

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

Furthermore, examples of the structural unit (a1) include the following groups. When the resin (A) includes the following structural units, the content thereof is preferably 10 to 95 mol%, more preferably 15 to 90 mol%, more preferably 20 to 85, based on all the structural units of the resin (A). More preferred is mol%.

  The structural unit (a) having an acid labile group in the resin (A) includes the structural unit (a1-0), the structural unit (a1-1), the structural unit (a1-2), and the structural unit (a1-5). At least one selected from the group consisting of) is more preferable, at least two or more are more preferable, and a combination of the structural unit (a1-1) and the structural unit (a1-2) is even more preferable.

<Structural unit (s)>
The structural unit (s) is derived from a monomer having no acid labile group (hereinafter sometimes referred to as “monomer (s)”). As the monomer for deriving the structural unit (s), a monomer having no acid labile group known in the resist field can be used.
As the structural unit (s), a structural unit having a hydroxy group or a lactone ring and having no acid labile group is preferable. A structure having a hydroxy group and having no acid labile group (hereinafter sometimes referred to as “structural unit (a2)”) and / or a lactone ring and having no acid labile group If a resin having a unit (hereinafter sometimes referred to as “structural unit (a3)”) is used in the resist composition of the present invention, the resolution of the resist pattern and the adhesion to the substrate can be improved.

<Structural unit (a2)>
The hydroxy group contained in the structural unit (a2) may be an alcoholic hydroxy group or a phenolic hydroxy group.
When a resist pattern is produced from the resist composition of the present invention, when a high energy beam such as a KrF excimer laser (248 nm), an electron beam or EUV (ultra-ultraviolet light) is used as an exposure light source, the structural unit (a2) It is preferable to use the structural unit (a2) having a phenolic hydroxy group. Further, when an ArF excimer laser (193 nm) or the like is used, the structural unit (a2) having an alcoholic hydroxy group is preferable as the structural unit (a2). As a structural unit (a2), 1 type may be included independently and 2 or more types may be included.

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

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

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

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

As a structural unit (a2-1), the structural unit derived from the monomer described in Unexamined-Japanese-Patent No. 2010-204646 is mentioned, for example. A structural unit represented by any one of formula (a2-1-1) to formula (a2-1-6) is preferred, and any one of formula (a2-1-1) to formula (a2-1-4) The structural unit represented is more preferable, and the structural unit represented by the formula (a2-1-1) or the formula (a2-1-3) is more preferable.

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

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

  The structural unit (a3) is preferably a structural unit represented by the formula (a3-1), the formula (a3-2), the formula (a3-3), or the formula (a3-4). One of these may be contained alone, or two or more thereof may be contained.

［式（ａ３−１）中、
Ｌ^a4は、−Ｏ−又は^＊−Ｏ−（ＣＨ₂）_k3−ＣＯ−Ｏ−（ｋ３は１〜７のいずれかの整数を表す。
）で表される基を表す。＊はカルボニル基との結合手を表す。
Ｒ^a18は、水素原子又はメチル基を表す。
Ｒ^a21は炭素数１〜４の脂肪族炭化水素基を表す。
ｐ１は０〜５のいずれかの整数を表す。ｐ１が２以上のとき、複数のＲ^a21は互いに同一又は相異なる。
式（ａ３−２）中、
Ｌ^a5は、−Ｏ−又は^＊−Ｏ−（ＣＨ₂）_k3−ＣＯ−Ｏ−（ｋ３は１〜７のいずれかの整数を表す。
）で表される基を表す。＊はカルボニル基との結合手を表す。
Ｒ^a19は、水素原子又はメチル基を表す。
Ｒ^a22は、カルボキシ基、シアノ基又は炭素数１〜４の脂肪族炭化水素基を表す。
ｑ１は、０〜３のいずれかの整数を表す。ｑ１が２以上のとき、複数のＲ^a22は互いに同一又は相異なる。
式（ａ３−３）中、
Ｌ^a6は、−Ｏ−又は^＊−Ｏ−（ＣＨ₂）_k3−ＣＯ−Ｏ−（ｋ３は１〜７のいずれかの整数を表す。
）で表される基を表す。＊はカルボニル基との結合手を表す。
Ｒ^a20は、水素原子又はメチル基を表す。
Ｒ^a23は、カルボキシ基、シアノ基又は炭素数１〜４の脂肪族炭化水素基を表す。
ｒ１は、０〜３のいずれかの整数を表す。ｒ１が２以上のとき、複数のＲ^a23は互いに同一又は相異なる。
式（ａ３−４）中、
Ｒ^a24は、ハロゲン原子を有していてもよい炭素数１〜６のアルキル基、水素原子又はハロゲン原子を表す。
Ｌ^a7は、−Ｏ−、^＊−Ｏ−Ｌ^a8−Ｏ−、^＊−Ｏ−Ｌ^a8−ＣＯ−Ｏ−、^＊−Ｏ−Ｌ^a8−ＣＯ−Ｏ−Ｌ^a9−ＣＯ−Ｏ−又は^＊−Ｏ−Ｌ^a8−Ｏ−ＣＯ−Ｌ^a9−Ｏ−を表す。
＊はカルボニル基との結合手を表す。
Ｌ^a8及びＬ^a9は、それぞれ独立に、炭素数１〜６のアルカンジイル基を表す。］

[In the formula (a3-1),
L ^a4 represents —O— or ^* —O— (CH ₂ ) _k3 —CO—O— (k3 represents an integer of 1 to 7).
) Represents a group represented by * Represents a bond with a carbonyl group.
R ^a18 represents a hydrogen atom or a methyl group.
R ^a21 represents an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
p1 represents any integer of 0 to 5. When p1 is 2 or more, the plurality of R ^a21 are the same or different from each other.
In formula (a3-2),
L ^a5 represents —O— or ^* —O— (CH ₂ ) _k3 —CO—O— (k3 represents an integer of 1 to 7).
) Represents a group represented by * Represents a bond with a carbonyl group.
R ^a19 represents a hydrogen atom or a methyl group.
R ^a22 represents a carboxy group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
q1 represents any integer of 0 to 3. When q1 is 2 or more, the plurality of R ^a22 are the same or different from each other.
In formula (a3-3),
L ^a6 represents —O— or ^* —O— (CH ₂ ) _k3 —CO—O— (k3 represents an integer of 1 to 7).
) Represents a group represented by * Represents a bond with a carbonyl group.
R ^a20 represents a hydrogen atom or a methyl group.
R ^a23 represents a carboxy group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
r1 represents any integer of 0 to 3. When r1 is 2 or more, the plurality of R ^a23 are the same or different from each other.
In formula (a3-4),
R ^a24 represents a C 1-6 alkyl group ^optionally having a halogen atom, a hydrogen atom, or a halogen atom.
L ^a7 is —O—, ^* —O—L ^a8 —O—, ^* —O—L ^a8 —CO—O—, ^* —O—L ^a8 —CO—O—L ^a9 —CO—O— or ^* —O—L ^a8 —O—CO—L ^a9 —O— is represented.
* Represents a bond with a carbonyl group.
L ^a8 and L ^a9 each independently represent an alkanediyl group having 1 to 6 carbon atoms. ]

Examples of the aliphatic hydrocarbon group for R ^a21 , R ^a22 and R ^a23 include alkyl groups such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group and tert-butyl group. Can be mentioned.
Examples of the halogen atom for R ^a24 include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
^Examples of the alkyl group for R ^a24 include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, and n-hexyl group. , Preferably it is a C1-C4 alkyl group, More preferably, it is a methyl group or an ethyl group.
Examples of the alkyl group having a halogen atom of R ^a24 include trifluoromethyl group, perfluoroethyl group, perfluoropropyl group, perfluoroisopropyl group, perfluorobutyl group, perfluorosec-butyl group, perfluorotert-butyl group, perfluoropentyl group, perfluoro group. A hexyl group, a trichloromethyl group, a tribromomethyl group, a triiodomethyl group, etc. are mentioned.

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

In formula (a3-1) to formula (a3-3), L ^{a4 to} L ^a6 are preferably each independently, preferably —O— or k3 is an integer of 1 to 4 * —O—. A group represented by (CH ₂ ) _k3 —CO—O—, more preferably —O— and * —O—CH ₂ —CO—O—, still more preferably an oxygen atom.
R ^{a18 to} R ^a21 are preferably methyl groups.
R ^a22 and R ^a23 are each independently preferably a carboxy group, a cyano group or a methyl group.
p1, q1 and r1 are each independently preferably an integer of 0 to 2, more preferably 0 or 1.

（式中、Ｒ^ａ２４、Ｌ^ａ７は、上記と同じ意味を表す。） In formula (a3-4),
R ^a24 is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom, a methyl group or an ethyl group, and still more preferably a hydrogen atom or a methyl group.
L ^a7 is preferably —O— or ^* —O—L ^a8 —CO—O—, and more preferably —O—, —O—CH ₂ —CO—O— or —O—C ₂ H. _4- CO-O-.
In formula (a3-4), formula (a3-4) ′ is particularly preferred.

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

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

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

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

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

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

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

Examples of the aliphatic saturated hydrocarbon group for L ⁴ include an alkanediyl group having 1 to 4 carbon atoms, such as a methylene group, an ethylene group, a propane-1,3-diyl group, and a butane-1,4-diyl group. Having a side chain of an alkyl group (particularly, methyl group, ethyl group, etc.), ethane-1,1-diyl group, propane-1, Examples thereof include branched alkanediyl groups such as 2-diyl group, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group and 2-methylpropane-1,2-diyl group.

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

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

Examples of the structural unit (a4-0) include the structural units shown below and a structural unit in which a methyl group corresponding to R ⁵ in the following structural units is replaced with a hydrogen atom.

［式（ａ４−１）中、
Ｒ^a41は、水素原子又はメチル基を表す。
Ｒ^a42は、置換基を有していてもよい炭素数１〜２０の炭化水素基を表し、該炭化水素基に含まれる−ＣＨ₂−は、−Ｏ−又は−ＣＯ−に置き換わっていてもよい。
Ａ^a41は、置換基を有していてもよい炭素数１〜６のアルカンジイル基又は式（ａ−ｇ１）で表される基を表す。ただし、Ａ^ａ４１及びＲ^ａ４２のうち少なくとも１つは、置換基としてハロゲン原子（好ましくはフッ素原子）を有する。

〔式（ａ−ｇ１）中、
ｓは０又は１を表す。
Ａ^a42及びＡ^a44は、それぞれ独立に、置換基を有していてもよい炭素数１〜５の２価の脂肪族炭化水素基を表す。
Ａ^a43は、単結合又は置換基を有していてもよい炭素数１〜５の２価の脂肪族炭化水素基を表す。
Ｘ^a41及びＸ^a42は、それぞれ独立に、−Ｏ−、−ＣＯ−、−ＣＯ−Ｏ−又は−Ｏ−ＣＯ−を表す。
ただし、Ａ^a42、Ａ^a43、Ａ^a44、Ｘ^a41及びＸ^a42の炭素数の合計は７以下である。〕
＊は結合手であり、右側の＊が−Ｏ−ＣＯ−Ｒ^a42との結合手である。］ As the structural unit (a4), a structural unit represented by formula (a4-1) can be given.

[In the formula (a4-1),
R ^a41 represents a hydrogen atom or a methyl group.
R ^a42 represents an ^optionally substituted hydrocarbon group having 1 to 20 carbon atoms, and —CH ₂ — contained in the hydrocarbon group may be replaced by —O— or —CO—. Good.
A ^a41 represents an ^optionally substituted alkanediyl group having 1 to 6 carbon atoms or a group represented by the formula (a-g1). However, at least one of A ^a41 and R ^a42 has a halogen atom (preferably a fluorine atom) as a substituent.

[In the formula (a-g1),
s represents 0 or 1.
A ^a42 and A ^a44 each independently represent a ^C 1-5 divalent aliphatic hydrocarbon group which may have a substituent.
A ^a43 represents a ^C1-C5 divalent aliphatic hydrocarbon group which may have a single bond or a substituent.
X ^a41 and X ^a42 each independently represent —O—, —CO—, ^—CO —O— or —O—CO—.
However, the total number of carbon atoms of A ^a42 , A ^a43 , A ^a44 , X ^a41 and X ^a42 is 7 or less. ]
* Is a bond, and * on the right side is a bond with —O—CO—R ^a42 . ]

^Examples of the hydrocarbon group for R ^a42 include chain and cyclic aliphatic hydrocarbon groups, aromatic hydrocarbon groups, and groups formed by combining these.
The chain and cyclic aliphatic hydrocarbon groups may have a carbon-carbon unsaturated bond, but the chain and cyclic aliphatic saturated hydrocarbon groups are preferable. The aliphatic saturated hydrocarbon group includes a straight chain or branched alkyl group and a monocyclic or polycyclic alicyclic hydrocarbon group, and an aliphatic group formed by combining an alkyl group and an alicyclic hydrocarbon group. Group hydrocarbon group and the like.

芳香族炭化水素基としては、フェニル基、ナフチル基、アントリル基、ビフェニリル基、フェナントリル基及びフルオレニル基が挙げられる。 Examples of chain aliphatic hydrocarbon groups include methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, and n-decyl. Group, n-dodecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group and n-octadecyl group. Cyclic aliphatic hydrocarbon groups include cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group and other cycloalkyl groups; decahydronaphthyl group, adamantyl group, norbornyl group and the following groups (* is a bond) And a polycyclic alicyclic hydrocarbon group such as).

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

［式（ａ−ｇ３）中、
Ｘ^a43は、酸素原子、カルボニル基、カルボニルオキシ基又はオキシカルボニル基を表す。
Ａ^a45は、少なくとも１つのハロゲン原子を有する炭素数１〜１７の脂肪族炭化水素基を表す。
＊は結合手を表す。］ The hydrocarbon group for R ^a42 is preferably a chain or cyclic aliphatic hydrocarbon group or a group formed by a combination thereof, and may have a carbon-carbon unsaturated bond. And a cyclic aliphatic saturated hydrocarbon group and a group formed by combining these are more preferable.
R ^a42 includes a halogen atom or a group represented by the formula (a-g3) as a substituent. As a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom are mentioned, Preferably it is a fluorine atom.

[In the formula (a-g3),
X ^a43 represents an oxygen atom, a carbonyl group, a carbonyloxy group or an oxycarbonyl group.
A ^a45 represents a C ^1-17 aliphatic hydrocarbon group having at least one halogen atom.
* Represents a bond. ]

^As the aliphatic hydrocarbon group for A ^a45, the same groups as those exemplified for R ^a42 can be mentioned.
R ^a42 is preferably an aliphatic hydrocarbon group which may have a halogen atom, more preferably an alkyl group having a halogen atom and / or an aliphatic hydrocarbon group having a group represented by the formula (a-g3). preferable.
When R ^a42 is an aliphatic hydrocarbon group having a halogen atom, it is preferably an aliphatic hydrocarbon group having a fluorine atom, more preferably a perfluoroalkyl group or a perfluorocycloalkyl group, and still more preferably a carbon number. It is a 1-6 perfluoroalkyl group, Most preferably, it is a C1-C3 perfluoroalkyl group. Examples of the perfluoroalkyl group include a perfluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluorobutyl group, a perfluoropentyl group, a perfluorohexyl group, a perfluoroheptyl group, and a perfluorooctyl group. Examples of the perfluorocycloalkyl group include a perfluorocyclohexyl group.
When R ^a42 is an aliphatic hydrocarbon group having a group represented by the formula (a-g3), including the carbon number contained in the group represented by the formula (a-g3), the aliphatic hydrocarbon The total carbon number of the group is preferably 15 or less, more preferably 12 or less. When it has a group represented by the formula (a-g3) as a substituent, the number is preferably 1.

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

[In the formula (a-g2),
A ^a46 represents an aliphatic hydrocarbon group having 1 to 17 carbon atoms which may have a halogen atom.
X ^a44 represents a carbonyloxy group or an oxycarbonyl group.
A ^a47 represents an aliphatic hydrocarbon group having 1 to 17 carbon atoms which may have a halogen atom.
However, the total number of carbon atoms of A ^a46 , A ^a47, and X ^a44 is 18 or less, and at least one of A ^a46 and A ^a47 has at least one halogen atom.
* Represents a bond with a carbonyl group. ]

1-6 are preferable and, as for carbon number of the aliphatic hydrocarbon group of ^Aa46 , 1-3 are more preferable.
4-15 are preferable, as for carbon number of the aliphatic hydrocarbon group of ^Aa47 , 5-12 are more preferable, and ^Aa47 has a cyclohexyl group or an adamantyl group further more preferable.

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

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

The aliphatic hydrocarbon group of A ^a42 , A ^a43 and A ^{a44 in} the group (a-g1) may have a carbon-carbon unsaturated bond, but a linear and cyclic aliphatic saturated hydrocarbon group In addition, groups formed by combining them are preferred. The aliphatic saturated hydrocarbon group is formed by combining a linear or branched alkyl group and a monocyclic or polycyclic alicyclic hydrocarbon group, and an alkyl group and an alicyclic hydrocarbon group. An aliphatic hydrocarbon group etc. are mentioned. Specifically, methylene group, ethylene group, propane-1,3-diyl group, propane-1,2-diyl group, butane-1,4-diyl group, 1-methylpropane-1,3-diyl group, Examples include 2-methylpropane-1,3-diyl group and 2-methylpropane-1,2-diyl group.
^Examples of the substituent for the aliphatic hydrocarbon group of A ^a42 , A ^a43 and A ^a44 include a hydroxy group and an alkoxy group having 1 to 6 carbon atoms.
s is preferably 0.

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

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

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

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

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

Examples of the hydrocarbon group having a fluorine atom for R ^f2 include an alkyl group having a fluorine atom and an alicyclic hydrocarbon group having a fluorine atom.
Examples of the alkyl group having a fluorine atom include a difluoromethyl group, a trifluoromethyl group, a 1,1-difluoroethyl group, a 2,2-difluoroethyl group, a 2,2,2-trifluoroethyl group, a perfluoroethyl group, 1 , 1,2,2-tetrafluoropropyl group, 1,1,2,2,3,3-hexafluoropropyl group, perfluoroethylmethyl group, 1- (trifluoromethyl) -1,2,2,2- Tetrafluoroethyl group, 1- (trifluoromethyl) -2,2,2-trifluoroethyl group, perfluoropropyl group, 1,1,2,2-tetrafluorobutyl group, 1,1,2,2,3 , 3-hexafluorobutyl group, 1,1,2,2,3,3,4,4-octafluorobutyl group, perfluorobutyl group, 1,1-bis (trifluoro) methyl 2,2,2-trifluoroethyl group, 2- (perfluoropropyl) ethyl group, 1,1,2,2,3,3,4,4-octafluoropentyl group, perfluoropentyl group, 1,1,2 , 2,3,3,4,4,5,5-decafluoropentyl group, 1,1-bis (trifluoromethyl) -2,2,3,3,3-pentafluoropropyl group, 2- (perfluoro Butyl) ethyl group, 1,1,2,2,3,3,4,4,5,5-decafluorohexyl group, 1,1,2,2,3,3,4,4,5,5 Fluorinated alkyl groups such as 6,6-dodecafluorohexyl group, perfluoropentylmethyl group and perfluorohexyl group can be mentioned.
Examples of the alicyclic hydrocarbon group having a fluorine atom include fluorinated cycloalkyl groups such as a perfluorocyclohexyl group and a perfluoroadamantyl group.

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

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

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

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

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

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

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

Examples of the structural unit represented by the formula (a4-2) include the structural units shown below and a structural unit in which a methyl group corresponding to R ^f1 in the following structural units is replaced with a hydrogen atom.

The structural unit represented by formula (a4-3), a methyl group have structural units replaced by a hydrogen atom corresponding to R ^f11 in the structural unit and the following structural units shown below.

Examples of the structural unit (a4) include the structural units described below and structural units in which a methyl group bonded to the main chain is replaced with a hydrogen atom.

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

［式（ａ５−１）中、
Ｒ⁵¹は、水素原子又はメチル基を表す。
Ｒ⁵²は、炭素数３〜１８の脂環式炭化水素基を表し、該脂環式炭化水素基に含まれる水素原子は炭素数１〜８の脂肪族炭化水素基で置換されていてもよい。但し、Ｌ⁵¹との結合位置にある炭素原子に結合する水素原子は、炭素数１〜８の脂肪族炭化水素基で置換されない。
Ｌ⁵¹は、単結合又は炭素数１〜１８の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれるメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。］ <Structural unit (a5)>
Examples of the non-leaving hydrocarbon group that the structural unit (a5) has include a linear, branched, or cyclic hydrocarbon group. Among these, the structural unit (a5) preferably includes an alicyclic hydrocarbon group.
As a structural unit (a5), the structural unit represented by a formula (a5-1) is mentioned, for example.

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

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

Examples of the divalent saturated hydrocarbon group for L ⁵¹ include a divalent aliphatic saturated hydrocarbon group and a divalent alicyclic saturated hydrocarbon group, preferably a divalent aliphatic saturated hydrocarbon group. .
Examples of the divalent aliphatic saturated hydrocarbon group include alkanediyl groups such as a methylene group, an ethylene group, a propanediyl group, a butanediyl group, and a pentanediyl group.
The divalent alicyclic saturated hydrocarbon group may be monocyclic or polycyclic. Examples of the monocyclic alicyclic saturated hydrocarbon group include cycloalkanediyl groups such as cyclopentanediyl group and cyclohexanediyl group. Examples of the polycyclic divalent alicyclic saturated hydrocarbon group include an adamantanediyl group and a norbornanediyl group.

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

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

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

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

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

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

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

L ⁵¹ is preferably a single bond or a group represented by the formula (L1-1).

As the structural unit (a5-1), structural units shown below and structural units in which a methyl group corresponding to R ⁵¹ in the following structural units is replaced with a hydrogen atom can be mentioned.

  When the resin (A) has the structural unit (a5), the content is preferably 1 to 30 mol%, more preferably 2 to 20 mol%, based on all structural units of the resin (A). More preferred is ˜15 mol%.

The resin (A) is preferably a resin composed of the structural unit (a1) and the structural unit (s), that is, a copolymer of the monomer (a1) and the monomer (s).
The structural unit (s) is preferably at least one of the structural unit (a2) and the structural unit (a3). The structural unit (a2) is preferably a structural unit represented by the formula (a2-1).
The structural unit (a3) is preferably selected from the structural unit represented by the formula (a3-1), the structural unit represented by the formula (a3-2), and the structural unit represented by the formula (a3-4). At least one kind.

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

<Resin other than resin (A)>
The resist composition of the present invention may contain a resin other than the resin (A). Examples of such a resin include a resin containing the structural unit (a4) (however, the structural unit (a1) is not included, and may be referred to as “resin (X)” hereinafter).
In the resin (X), the content of the structural unit (a4) is preferably 40 mol% or more, more preferably 45 mol% or more, and still more preferably 50 mol% or more with respect to all the structural units of the resin (X). .
Examples of the structural unit that the resin (X) may further include a structural unit derived from the structural unit (a2), the structural unit (a3), and other known monomers.
The weight average molecular weight of the resin (X) is preferably 6,000 or more (more preferably 7,000 or more) and 80,000 or less (more preferably 60,000 or less). The means for measuring the weight average molecular weight of the resin (X) is the same as that for the resin (A).
When the resist composition contains the resin (X), the content thereof is preferably 1 to 60 parts by mass, more preferably 2 to 50 parts by mass with respect to 100 parts by mass of the resin (A). Preferably it is 2-40 mass parts, Most preferably, it is 3-30 mass parts.

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

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

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

<Quencher (C)>
Examples of the quencher (C) include a salt that generates an acid having a lower acidity than an acid generated from the salt (aa) and the acid generator (B), or a basic nitrogen-containing organic compound.

<Basic nitrogen-containing organic compound>
Examples of the basic nitrogen-containing organic compound include amines and ammonium salts. Examples of amines include aliphatic amines and aromatic amines. Aliphatic amines include primary amines, secondary amines and tertiary amines.
Specifically, 1-naphthylamine, 2-naphthylamine, aniline, diisopropylaniline, 2-, 3- or 4-methylaniline, 4-nitroaniline, N-methylaniline, N, N-dimethylaniline, diphenylamine, hexylamine , Heptylamine, octylamine, nonylamine, decylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, triethylamine, trimethylamine, tripropylamine, tributylamine, tripentylamine, trihexylamine, Triheptylamine, trioctylamine, trinonylamine, tridecylamine, methyldibutylamine, methyldipentylamine, methyldihexylamine, methyl Cyclohexylamine, methyldiheptylamine, methyldioctylamine, methyldinonylamine, methyldidecylamine, ethyldibutylamine, ethyldipentylamine, ethyldihexylamine, ethyldiheptylamine, ethyldioctylamine, ethyldinonylamine, ethyldinonylamine Decylamine, dicyclohexylmethylamine, tris [2- (2-methoxyethoxy) ethyl] amine, triisopropanolamine, ethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4′-diamino-1,2-diphenylethane, 4 4,4′-diamino-3,3′-dimethyldiphenylmethane, 4,4′-diamino-3,3′-diethyldiphenylmethane, piperazine, morpholine, piperidine and JP-A-11-52575 Hindered amine compounds having a piperidine skeleton described in the publication, imidazole, 4-methylimidazole, pyridine, 4-methylpyridine, 1,2-di (2-pyridyl) ethane, 1,2-di (4-pyridyl) ethane 1,2-di (2-pyridyl) ethene, 1,2-di (4-pyridyl) ethene, 1,3-di (4-pyridyl) propane, 1,2-di (4-pyridyloxy) ethane, Examples include di (2-pyridyl) ketone, 4,4′-dipyridyl sulfide, 4,4′-dipyridyl disulfide, 2,2′-dipyridylamine, 2,2′-dipicolylamine, bipyridine, and preferably diisopropyl. Aniline is exemplified, and 2,6-diisopropylaniline is particularly preferred.

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

<Salt that generates acid with low acidity>
The acidity in a salt that generates an acid having a weaker acidity than the acid generated from the salt (aa) and the acid generator (B) is represented by an acid dissociation constant (pKa). The salt that generates an acid having a lower acidity than the acid generated from the salt (aa) and the acid generator (B) is a salt in which the acid dissociation constant of the acid generated from the salt is usually −3 <pKa, A salt of −1 <pKa <7 is preferable, and a salt of 0 <pKa <5 is more preferable. Examples of the salt that generates an acid having a lower acidity than the acid generated from the acid generator (B) include salts represented by the following formulas, JP2012-229206A, JP2012-6908A, Examples thereof include salts described in JP 2012-72109 A, JP 2011-39502 A, and JP 2011-191745 A.

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

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

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

[Resist pattern manufacturing method]
The method for producing a resist pattern of the present invention comprises:
(1) A step of applying the resist composition of the present invention on a substrate,
(2) The process of drying the composition after application | coating and forming a composition layer,
(3) a step of exposing the composition layer;
(4) a step of heating the composition layer after exposure, and (5) a step of developing the composition layer after heating.

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

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

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

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

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

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

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

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

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

The present invention will be described more specifically with reference to examples. In the examples, “%” and “parts” representing the content or amount used are based on mass unless otherwise specified.
The weight average molecular weight is a value determined by gel permeation chromatography. The analysis conditions for gel permeation chromatography are as follows.
Column: TSKgel Multipore HXL-M x 3 + guardcolumn (manufactured by Tosoh Corporation)
Eluent: Tetrahydrofuran Flow rate: 1.0 mL / min
Detector: RI detector Column temperature: 40 ° C
Injection volume: 100 μl
Molecular weight standard: Standard polystyrene (manufactured by Tosoh Corporation)

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

式（Ｉ−１−ａ）で表される塩１．８部、クロロホルム１０部及びピリジン０．６部を混合し、２３℃で３０分間攪拌した後、５℃まで冷却した。得られた混合溶液に、式（Ｉ−１−ｂ）で表される化合物１．２部を１時間かけて滴下し、さらに２３℃で１時間攪拌した。得られた反応溶液を濃縮した後、得られた濃縮残渣に、クロロホルム４０部及び５％シュウ酸水溶液２．８部を仕込み、２３℃で３０分間攪拌し、分液することにより有機層を回収した。回収された有機層に、イオン交換水２０部を仕込み２３℃で３０分間攪拌し、分液することにより有機層を回収した。この水洗の操作を５回行った。得られた有機層を濃縮した後、濃縮残渣にアセトニトリル１．４５部及び酢酸エチル２２部を加えて攪拌した後、上澄液を除去した。得られた残渣をアセトニトリルに溶解し、濃縮することにより、式（Ｉ−１）で表される塩１．４５部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ２６３．１
ＭＡＳＳ（ＥＳＩ（−）Ｓｐｅｃｔｒｕｍ）：Ｍ⁻ ６２７．０ Example 1: Synthesis of a salt represented by the formula (I-1)

1.8 parts of the salt represented by the formula (I-1-a), 10 parts of chloroform and 0.6 part of pyridine were mixed, stirred at 23 ° C. for 30 minutes, and then cooled to 5 ° C. To the obtained mixed solution, 1.2 parts of the compound represented by the formula (I-1-b) was added dropwise over 1 hour, and the mixture was further stirred at 23 ° C. for 1 hour. After concentrating the obtained reaction solution, 40 parts of chloroform and 2.8 parts of 5% aqueous oxalic acid solution were added to the resulting concentrated residue, stirred at 23 ° C. for 30 minutes, and separated to recover the organic layer. did. To the collected organic layer, 20 parts of ion-exchanged water was charged, stirred at 23 ° C. for 30 minutes, and separated to recover the organic layer. This washing operation was performed 5 times. After the obtained organic layer was concentrated, 1.45 parts of acetonitrile and 22 parts of ethyl acetate were added to the concentrated residue and stirred, and then the supernatant was removed. The obtained residue was dissolved in acetonitrile and concentrated to obtain 1.45 parts of the salt represented by the formula (I-1).
MASS (ESI (+) Spectrum): M ⁺ 263.1
MASS (ESI (−) Spectrum): M ^- 627.0

式（Ｉ−８１−ａ）で表される塩１．７４部、クロロホルム１０部及びピリジン０．５９部を混合し、２３℃で３０分間攪拌した後、５℃まで冷却した。得られた混合溶液に、式（Ｉ−１−ｂ）で表される化合物１．１５部を１時間かけて滴下し、さらに２３℃で１時間攪拌した。得られた反応溶液を濃縮した後、得られた濃縮残渣に、クロロホルム４０部及び５％シュウ酸水溶液２．８部を仕込み、２３℃で３０分間攪拌し、分液することにより有機層を回収した。回収された有機層に、イオン交換水２０部を仕込み２３℃で３０分間攪拌し、分液することにより有機層を回収した。この水洗の操作を５回行った。得られた有機層を濃縮した後、濃縮残渣にアセトニトリル１部及びｔｅｒｔ−ブチルメチルエーテル３０部を加えて攪拌した後、上澄液を除去した。得られた残渣をアセトニトリルに溶解し、濃縮することにより、式（Ｉ−８１）で表される塩１．３２部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ２３７．１
ＭＡＳＳ（ＥＳＩ（−）Ｓｐｅｃｔｒｕｍ）：Ｍ⁻ ６２７．０ Example 2: Synthesis of salt represented by formula (I-81)

1.74 parts of the salt represented by the formula (I-81-a), 10 parts of chloroform and 0.59 parts of pyridine were mixed, stirred at 23 ° C. for 30 minutes, and then cooled to 5 ° C. To the obtained mixed solution, 1.15 parts of the compound represented by the formula (I-1-b) was added dropwise over 1 hour, and the mixture was further stirred at 23 ° C. for 1 hour. After concentrating the obtained reaction solution, 40 parts of chloroform and 2.8 parts of 5% aqueous oxalic acid solution were added to the resulting concentrated residue, stirred at 23 ° C. for 30 minutes, and separated to recover the organic layer. did. To the collected organic layer, 20 parts of ion-exchanged water was charged, stirred at 23 ° C. for 30 minutes, and separated to recover the organic layer. This washing operation was performed 5 times. After concentrating the obtained organic layer, 1 part of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentrated residue and stirred, and then the supernatant was removed. The obtained residue was dissolved in acetonitrile and concentrated to obtain 1.32 parts of the salt represented by the formula (I-81).
MASS (ESI (+) Spectrum): M ⁺ 237.1
MASS (ESI (−) Spectrum): M ^- 627.0

式（Ｉ−８１−ａ）で表される塩１．７４部、クロロホルム１０部及びピリジン０．５９部を混合し、２３℃で３０分間攪拌した後、５℃まで冷却した。得られた混合溶液に、式（Ｉ−８５−ｂ）で表される化合物１．５２部を１時間かけて滴下し、さらに２３℃で１時間攪拌した。得られた反応溶液を濃縮した後、得られた濃縮残渣に、クロロホルム４０部及び５％シュウ酸水溶液２．８部を仕込み、２３℃で３０分間攪拌し、分液することにより有機層を回収した。回収された有機層に、イオン交換水２０部を仕込み２３℃で３０分間攪拌し、分液することにより有機層を回収した。この水洗の操作を５回行った。得られた有機層を濃縮した後、濃縮残渣にアセトニトリル１部及びｔｅｒｔ−ブチルメチルエーテル３０部を加えて攪拌した後、上澄液を除去した。得られた残渣をアセトニトリルに溶解し、濃縮することにより、式（Ｉ−８５）で表される塩１．２５部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ２３７．１
ＭＡＳＳ（ＥＳＩ（−）Ｓｐｅｃｔｒｕｍ）：Ｍ⁻ ６７７．０ Example 3: Synthesis of a salt represented by the formula (I-85)

1.74 parts of the salt represented by the formula (I-81-a), 10 parts of chloroform and 0.59 parts of pyridine were mixed, stirred at 23 ° C. for 30 minutes, and then cooled to 5 ° C. To the obtained mixed solution, 1.52 parts of the compound represented by the formula (I-85-b) was added dropwise over 1 hour, and the mixture was further stirred at 23 ° C. for 1 hour. After concentrating the obtained reaction solution, 40 parts of chloroform and 2.8 parts of 5% aqueous oxalic acid solution were added to the resulting concentrated residue, stirred at 23 ° C. for 30 minutes, and separated to recover the organic layer. did. To the collected organic layer, 20 parts of ion-exchanged water was charged, stirred at 23 ° C. for 30 minutes, and separated to recover the organic layer. This washing operation was performed 5 times. After concentrating the obtained organic layer, 1 part of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentrated residue and stirred, and then the supernatant was removed. The obtained residue was dissolved in acetonitrile and concentrated to obtain 1.25 parts of the salt represented by the formula (I-85).
MASS (ESI (+) Spectrum): M ⁺ 237.1
MASS (ESI (−) Spectrum): M ^- 677.0

式（Ｉ−８１−ａ）で表される塩１．７４部、クロロホルム１０部及びピリジン０．５９部を混合し、２３℃で３０分間攪拌した後、５℃まで冷却した。得られた混合溶液に、式（Ｉ−８９−ｂ）で表される化合物１．３９部を１時間かけて滴下し、さらに２３℃で１時間攪拌した。得られた反応溶液を濃縮した後、得られた濃縮残渣に、クロロホルム４０部及び５％シュウ酸水溶液２．８部を仕込み、２３℃で３０分間攪拌し、分液することにより有機層を回収した。回収された有機層に、イオン交換水２０部を仕込み２３℃で３０分間攪拌し、分液することにより有機層を回収した。この水洗の操作を５回行った。得られた有機層を濃縮した後、濃縮残渣にアセトニトリル１部及びｔｅｒｔ−ブチルメチルエーテル３０部を加えて攪拌した後、上澄液を除去した。得られた残渣をアセトニトリルに溶解し、濃縮することにより、式（Ｉ−８９）で表される塩１．０８部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ２３７．１
ＭＡＳＳ（ＥＳＩ（−）Ｓｐｅｃｔｒｕｍ）：Ｍ⁻ ６５９．１ Example 4: Synthesis of salt represented by formula (I-89)

1.74 parts of the salt represented by the formula (I-81-a), 10 parts of chloroform and 0.59 parts of pyridine were mixed, stirred at 23 ° C. for 30 minutes, and then cooled to 5 ° C. To the obtained mixed solution, 1.39 parts of the compound represented by the formula (I-89-b) was added dropwise over 1 hour, and the mixture was further stirred at 23 ° C. for 1 hour. After concentrating the obtained reaction solution, 40 parts of chloroform and 2.8 parts of 5% aqueous oxalic acid solution were added to the resulting concentrated residue, stirred at 23 ° C. for 30 minutes, and separated to recover the organic layer. did. To the collected organic layer, 20 parts of ion-exchanged water was charged, stirred at 23 ° C. for 30 minutes, and separated to recover the organic layer. This washing operation was performed 5 times. After concentrating the obtained organic layer, 1 part of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentrated residue and stirred, and then the supernatant was removed. The obtained residue was dissolved in acetonitrile and concentrated to obtain 1.08 parts of the salt represented by the formula (I-89).
MASS (ESI (+) Spectrum): M ⁺ 237.1
MASS (ESI (−) Spectrum): M ^- 659.1

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

Synthesis Example 1: Synthesis of Resin A1 As the monomer, monomer (a1-1-3), monomer (a1-2-9), monomer (a2-1-3) and monomer (a3-4-2) were used. The molar ratio [monomer (a1-1-3): monomer (a1-2-9): monomer (a2-1-3): monomer (a3-4-2)] is 45: 14: 2.5: 38. The resulting mixture was mixed with propylene glycol monomethyl ether acetate having a mass ratio of 1.5 times the total monomer amount to obtain a solution. To this solution, 1 mol% and 3 mol% of azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added to the total monomer amount, respectively, and these were heated at 73 ° C. for about 5 hours. did. The obtained reaction mixture was poured into a large amount of methanol / water mixed solvent to precipitate the resin, and this resin was filtered. The obtained resin was again dissolved in propylene glycol monomethyl ether acetate, and the resulting solution was poured into a methanol / water mixed solvent to precipitate the resin, followed by reprecipitation operation of filtering the resin twice. Resin A1 having a molecular weight of 7.6 × 10 ³ was obtained in a yield of 68%. This resin A1 has the following structural units.

Synthesis Example 2: Synthesis of Resin X1 Monomer (a4-1-7) was used as a monomer, and 1.5 mass times of methyl isobutyl ketone as a total monomer amount was added to obtain a solution. To this solution, 0.7 mol% and 2.1 mol% of azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile), respectively, as initiators were added with respect to the total monomer amount, and these were added at 75 ° C. Heated for about 5 hours. The obtained reaction mixture was poured into a large amount of a methanol / water mixed solvent to precipitate a resin, and this resin was filtered to obtain a resin X1 having a weight average molecular weight of 1.7 × 10 ^{4 in} a yield of 77%. This resin X1 has the following structural units.

Synthesis Example 3: Synthesis of Resin X2 Monomer (a5-1-1) and monomer (a4-0-12) were used as monomers, and the molar ratio [monomer (a5-1-1): monomer (a4-0- 12)] was 50:50, and methyl isobutyl ketone 1.2 mass times the total monomer amount was added to obtain a solution. To this solution, 3 mol% of azobis (2,4-dimethylvaleronitrile) as an initiator was added based on the total amount of monomers, and heated at 70 ° C. for about 5 hours. The obtained reaction mixture was poured into a large amount of a methanol / water mixed solvent to precipitate a resin, and this resin was filtered to obtain a resin X having a weight average molecular weight of 1.0 × 10 ^{4 in} a yield of 91%. This resin X2 has the following structural units.

<Preparation of resist composition>
As shown in Table 5, the following components were mixed, and the resulting mixture was filtered through a fluororesin filter having a pore size of 0.2 μm to prepare a resist composition.

<Resin>
A1, X1, X2: Resin A1, Resin X1, Resin X2
<Salt (aa)>
I-1: Salt represented by formula (I-1) I-81: Salt represented by formula (I-81) I-85: Salt represented by formula (I-85) I-89: Formula Salt represented by (I-89) <Acid generator (B)>
B1-21: a salt represented by the formula (B1-21) (synthesized according to Examples in JP 2012-224611 A)
B1-22: a salt represented by the formula (B1-22) (synthesized according to Examples in JP 2012-224611 A)
IX-1: synthesized according to the examples of JP-A-2014-189534

<Quencher (C)>
D1: (Tokyo Chemical Industry Co., Ltd.)

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

<Manufacture of resist pattern and its evaluation>
An organic antireflective coating composition (ARC-29; manufactured by Nissan Chemical Co., Ltd.) is applied to a silicon wafer and baked at 205 ° C. for 60 seconds to form an organic reflective film having a thickness of 78 nm on the wafer. A prevention film was formed. Next, on the organic antireflection film, the above resist composition was applied (spin coated) so that the film thickness after drying was 85 nm. After coating, the silicon wafer was pre-baked on a direct hot plate at the temperature described in the “PB” column of Table 5 for 60 seconds to form a composition layer. ArF excimer stepper for immersion exposure (XT: 1900 Gi; manufactured by ASML, NA = 1.35, 3/4 Annular XY polarized light) on a silicon wafer on which the composition layer is formed, and a contact hole pattern (hole pitch 90 nm) Using a mask for forming a hole diameter of 55 nm), the exposure amount was changed stepwise. Note that ultrapure water was used as the immersion medium.
After the exposure, post-exposure baking was performed for 60 seconds on the hot plate at the temperature described in the “PEB” column of Table 5. Next, the composition layer on the silicon wafer is developed by using a butyl acetate (manufactured by Tokyo Chemical Industry Co., Ltd.) as a developing solution by a dynamic dispensing method at 23 ° C. for 20 seconds, thereby forming a negative resist pattern. Manufactured.

  In the resist pattern obtained after development, the exposure amount at which the hole diameter formed using the mask was 50 nm was defined as the effective sensitivity.

<Evaluation of CD uniformity (CDU)>
In terms of effective sensitivity, the hole diameter of a pattern formed with a mask having a hole diameter of 55 nm was measured 24 times per hole, and the average value was taken as the average hole diameter of one hole. A standard deviation is obtained using a population obtained by measuring 400 average hole diameters of a pattern formed with a mask having a hole diameter of 55 nm in the same wafer,
When the standard deviation is 1.70 nm or less,
The case where the standard deviation was larger than 1.70 nm was judged as “x”.
The results are shown in Table 6. Numerical values in parentheses indicate standard deviation (nm).

<Manufacture of resist pattern and its evaluation>
An organic antireflection film having a thickness of 780 mm is formed by applying a composition for organic antireflection film (ARC-29; manufactured by Nissan Chemical Co., Ltd.) to a silicon wafer and baking it at 205 ° C. for 60 seconds. Formed. Subsequently, the resist composition was spin-coated on the organic antireflection film so that the film thickness after drying (pre-baking) was 85 nm. The silicon wafer coated with the resist composition was pre-baked on a direct hot plate at the temperature described in the “PB” column of Table 5 for 60 seconds to form a resist film (composition layer). An ArF excimer laser stepper for immersion exposure (XT: 1900 Gi; manufactured by ASML, NA = 1.35, 3/4 Annular XY polarized light) on a silicon wafer on which a resist film is formed, and a contact hole pattern (hole pitch 150 nm) Using a mask for forming a hole diameter of 75 nm), the exposure amount was changed stepwise. Note that ultrapure water was used as the immersion medium.
After the exposure, the silicon wafer was post-exposure baked for 60 seconds at a temperature described in the “PEB” column of Table 5 on a hot plate. Next, this silicon wafer was subjected to paddle development for 60 seconds with a 2.38% tetramethylammonium hydroxide aqueous solution to obtain a resist pattern.

In the formation of a resist pattern from each resist composition, the exposure amount at which the hole diameter of a pattern formed with a mask having a hole diameter of 75 nm was 55 nm was defined as effective sensitivity.
In manufacturing the resist pattern as described above, the following items were evaluated.

<Evaluation of CD uniformity (CDU)>
In terms of effective sensitivity, the hole diameter of a pattern formed with a mask having a hole diameter of 75 nm was measured 24 times per hole, and the average value was taken as the average hole diameter of one hole. Obtain a standard deviation using a population of 400 measured average hole diameters of patterns formed with a mask with a hole diameter of 75 nm in the same wafer,
When the standard deviation is 1.80 nm or less,
The case where the standard deviation was larger than 1.80 nm was judged as “x”.
The results are shown in Table 7. Numerical values in parentheses indicate standard deviation (nm).

  Since the resist composition containing the salt of the present invention can produce a resist pattern with good CD uniformity, it is suitable for fine processing of semiconductors.

Claims (12)

A salt having a group represented by the formula (aa1).

[In the formula (aa1),
X ^a and X ^b each independently represent an oxygen atom or a sulfur atom.
Ring W ¹ represents a C3-C36 heterocyclic ring having an ester bond or a thioester bond in the ring structure, and —CH ₂ — contained in the heterocyclic ring is —O—, —S—, —CO—. or -SO 2 _- may be substituted with, the heterocyclic ring may have a substituent.
Ring W ² represents an alicyclic hydrocarbon group having 3 to 36 carbon atoms which may have a substituent, and —CH ₂ — contained in the alicyclic hydrocarbon group is —O—, — S -, - CO- or -SO ₂ - may be substituted with. However, the ring W ² has at least one base-dissociable group.
* Represents a bond. ]   The salt according to claim 1, comprising an anion having a group represented by the formula (aa1) and a cation.   The salt according to claim 2, wherein the anion having a group represented by the formula (aa1) is an anion having a group represented by the formula (aa1) and a sulfonate. The salt according to claim 1, wherein the salt having a group represented by the formula (aa1) is a salt having an anion represented by the formula (aa2).

[In the formula (aa2),
X ^a , X ^b , ring W ¹ and ring W ² represent the same meaning as described above.
L ^b1 represents a divalent saturated hydrocarbon group having 1 to 24 carbon atoms, and —CH ₂ — contained in the saturated hydrocarbon group may be replaced by —O— or —CO—, and The hydrogen atom contained in the hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
Q ¹ and Q ² each independently represents a fluorine atom or a C 1-6 perfluoroalkyl group. ] The salt according to any one of claims 1 to 4, wherein the base dissociable group is a group represented by the formula (Ba) or a group represented by the formula (Bb).

[In Formula (Ba), R ²³ represents a C 1-6 alkyl group having a fluorine atom.
In the formula (Bb), R ²⁴ represents a C 1-6 alkyl group having a fluorine atom.
R ²⁵ and R ²⁶ each independently represents an alkyl group having 1 to 6 carbon atoms which may have a fluorine atom, a hydrogen atom or a fluorine atom. ] Ring W ¹ is A salt according to claim 1 is a heterocyclic ring represented by formula (W-1) represented by heterocycle or formula (W-2).

[In Formula (W-1) and Formula (W-2),
The hydrogen atom contained in the heterocyclic ring is a hydroxy group, a cyano group, a carboxyl group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms, or It may be substituted with an aromatic hydrocarbon group having 6 to 10 carbon atoms. ] Ring ^{W 2} is represented by Formula ring represented by (W1-1), the ring represented by the formula (w1-2), ring or the formula represented by the formula (w1-3) (w1-6) The salt according to any one of claims 1 to 6, wherein the salt is a ring.

[In formula (w1-1), formula (w1-2), formula (w1-3) and formula (w1-6),
—CH ₂ — contained in the ring may be substituted with —O—, —S—, —CO— or —SO ₂ —,
The ring has at least one base dissociable group, and is a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alkoxycarbonyl group having 2 to 13 carbon atoms, or 2 to 2 carbon atoms. One or more selected from the group consisting of 13 alkylcarbonyl groups, C2-13 alkylcarbonyloxy groups, C3-12 alicyclic hydrocarbon groups, and C6-10 aromatic hydrocarbon groups It may have a substituent. ] L ^b1 represents * 1-CO—O— (CH ₂ ) _t — (t represents an integer of 0 to 6. * 1 represents a bond to —C (Q ¹ ) (Q ² ) —. The salt according to any one of claims 5 to 7.   The acid generator containing the salt in any one of Claims 1-8.   A resist composition comprising the acid generator according to claim 9 and a resin having an acid labile group.   Furthermore, the resist composition of Claim 10 containing the salt which generate | occur | produces the acid whose acidity is weaker than the acid generated from an acid generator. (1) The process of apply | coating the resist composition of Claim 10 or 11 on a board | substrate,
(2) The process of drying the composition after application | coating and forming a composition layer,
(3) a step of exposing the composition layer;
(4) a step of heating the composition layer after exposure, and (5) a step of developing the composition layer after heating,
A method for producing a resist pattern including: