JP2021155428A - Salt, acid generator, resist composition, and method for producing resist pattern - Google Patents

Abstract

To provide a salt capable of producing a resist pattern having a good mask error factor (MEF) and a resist composition containing the salt.SOLUTION: The salt has an anion represented by formula (aa2) [where, in the formula(aa2), Xa and Xb each independently represent an oxygen atom or a sulfur atom; ring W1 and ring W2 each independently represent a ring represented by formula (w1-1) or the like; a hydrogen atom contained in the ring may be substituted with a hydroxy group or the like; Lb1 represents a group represented by formula (b1-2) or the like; and Q1 and Q2 each independently represent a fluorine atom or a C1-6 perfluoroalkyl group].SELECTED DRAWING: None

Description

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

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

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

Japanese Unexamined Patent Publication No. 2011-37837 Japanese Unexamined Patent Publication No. 2012-193160

In the resist composition containing the above salt, the mask error factor (MEF) of the obtained resist pattern may not always be satisfactory.

［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及び環Ｗ^２は、それぞれ独立に、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のアシル基、炭素数２〜１３のアシルオキシ基、炭素数３〜１２の脂環式炭化水素基、炭素数６〜１０の芳香族炭化水素基又はこれらを組み合わせた基で置換されていてもよい。
＊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］〜［３］のいずれかに記載の塩。

［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、互いに独立に、フッ素原子又は炭素数１〜６のペルフルオロアルキル基を表す。］
［５］環Ｗ^１及び環Ｗ^２が、それぞれ独立に、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］〜［４］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のアシル基、炭素数２〜１３のアシルオキシ基、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。］
［６］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［４］又は［５］に記載の塩。
［７］［１］〜［６］のいずれかに記載の塩を含有する酸発生剤。
［８］［７］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。
［９］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［８］に記載のレジスト組成物。
［１０］（１）［８］又は［９］記載のレジスト組成物を基板上に塗布する工程、
（２）塗布後の組成物を乾燥させて組成物層を形成する工程、
（３）組成物層に露光する工程、
（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 equation (aa1),
X ^a and X ^b independently represent an oxygen atom or a sulfur atom, respectively.
Ring W ¹ and ring W ² independently represent an alicyclic hydrocarbon group having 3 to 36 carbon atoms, and the hydrogen atom contained in the alicyclic hydrocarbon group is a hydroxy group and 1 to 12 carbon atoms. Alkoxy group, alkoxy group having 1 to 12 carbon atoms, alkoxycarbonyl group having 2 to 13 carbon atoms, acyl group having 2 to 13 carbon atoms, acyloxy group having 2 to 13 carbon atoms, alicyclic group having 3 to 12 carbon atoms. It may be substituted with a hydrocarbon group, an aromatic hydrocarbon group having 6 to 10 carbon atoms, or a group in which these are combined.
* Represents a bond. ]
[2] The salt according to [1], which comprises an anion and a cation having a group represented by the formula (aa1).
[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 sulfonate.
[4] The salt according to any one of [1] to [3], wherein the salt having a group represented by the formula (aa1) is a salt having an anion represented by the formula (aa2).

[In equation (aa2),
X ^a , X ^b , ring W ¹ and ring W ² have the same meanings as described above.
L ^b1 represents a divalent saturated hydrocarbon group having 1 to 24 carbon atoms, and the methylene group contained in the saturated hydrocarbon group may be replaced with an oxygen atom or a carbonyl group, and the saturated hydrocarbon group may be used. The contained hydrogen atom may be substituted with a fluorine atom or a hydroxy group.
Q ¹ and Q ² independently represent a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms. ]
[5] ring ^{W 1} and ring ^{W 2} are each independently represented by Formula ring represented by (W1-1), the ring represented by the formula (w1-2), formula (W1-3) The salt according to any one of [1] to [4], which is a ring or a ring represented by the formula (w1-6).

[In the formula (w1-1), the formula (w1-2), the formula (w1-3) and the formula (w1-6),
The hydrogen atom contained in the ring 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, an acyl group having 2 to 13 carbon atoms, and a carbon number of carbon atoms. It may be substituted with an acyloxy group of 2 to 13, an alicyclic hydrocarbon group having 3 to 12 carbon atoms, or an aromatic hydrocarbon group having 6 to 10 carbon atoms. ]
[6] 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 [4] or [5].
[7] An acid generator containing the salt according to any one of [1] to [6].
[8] A resist composition containing the acid generator according to [7] and a resin having an acid unstable group.
[9] The resist composition according to [8], which further contains a salt that generates an acid having a weaker acidity than the acid generated from the acid generator.
[10] (1) A step of applying the resist composition according to [8] or [9] onto a substrate.
(2) A step of drying the applied composition to form a composition layer,
(3) 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.

Provided is a salt capable of producing a resist pattern of good mask error factor (MEF).

As used herein, the term "(meth) acrylic monomer" means at least one type of monomer having a structure of _{"CH 2} = CH-CO-" or "CH ₂ = C (CH _{3) -CO-".} 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. In addition, any of the groups described in the present specification that can have both a linear structure and a branched structure may be used. If a steric isomer is present, it includes all the steric isomers.
In the present specification, the "solid content of the resist composition" means the total amount of the 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及び環Ｗ^２は、それぞれ独立に、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のアシル基、炭素数２〜１３のアシルオキシ基、炭素数３〜１２の脂環式炭化水素基、炭素数６〜１０の芳香族炭化水素基又はこれらを組み合わせた基で置換されていてもよい。
＊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, may be referred to as “salt (aa)”).

[In equation (aa1),
X ^a and X ^b independently represent an oxygen atom or a sulfur atom, respectively.
Ring W ¹ and ring W ² independently represent an alicyclic hydrocarbon group having 3 to 36 carbon atoms, and the hydrogen atom contained in the alicyclic hydrocarbon group is a hydroxy group and 1 to 12 carbon atoms. Alkoxy group, alkoxy group having 1 to 12 carbon atoms, alkoxycarbonyl group having 2 to 13 carbon atoms, acyl group having 2 to 13 carbon atoms, acyloxy group having 2 to 13 carbon atoms, alicyclic group having 3 to 12 carbon atoms. It may be substituted with a hydrocarbon group, an aromatic hydrocarbon group having 6 to 10 carbon atoms, or a group in which these are combined.
* Represents a bond. ]

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

［式（ｗ１−１）〜式（ｗ１−１１）中、
環に含まれる水素原子は、ヒドロキシ基、炭素数１〜１２のアルキル基、炭素数１〜１２のアルコキシ基、炭素数３〜１２の脂環式炭化水素基又は炭素数６〜１０の芳香族炭化水素基で置換されていてもよい。］ The alicyclic hydrocarbon groups represented by the ring W ¹ and ring W ^2, may be a monocyclic, may be a polycyclic, and specifically, the formula (W1-1) Examples thereof include groups derived from the ring represented by the formula (w1-11).
It is preferable that the ring W ¹ and the ring W ² are independently alicyclic hydrocarbon groups having 3 to 18 carbon atoms, and the ring represented by the formula (w1-1) and the ring W1-2 are represented by the formula (w1-2). more preferably a ring represented by the ring or the formula (W1-3) represented, ring ^{W 1} ring is more preferably represented by the formula (w1-2), ring ^{W 2} is formula (W1- The ring represented by 1) is more preferable.

[In equations (w1-1) to (w1-11),
The hydrogen atom contained in the ring is a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms, or an aromatic having 6 to 10 carbon atoms. It may be substituted with a hydrocarbon group. ]

環Ｗ^１及び環Ｗ^２の置換基である炭素数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。
環Ｗ^１及び環Ｗ^２の置換基である炭素数２〜１３のアルコキシカルボニル基としては、メトキシカルボニル基、エトキシカルボニル基、プロポキシカルボニル基、ブトキシカルボニル基、ペンチルオキシカルボニル基、ヘキシルオキシカルボニル基、オクチルオキシカルボニル基、２−エチルヘキシルオキシカルボニル基、ノニルオキシカルボニル基、デシルオキシカルボニル基、ウンデシルオキシカルボニル基及びドデシルオキシカルボニル基等が挙げられる。
環Ｗ^１及び環Ｗ^２の置換基である炭素数２〜１３のアシル基としては、アセチル基、プロピオニル基及びブチリル基等が挙げられる。
環Ｗ^１及び環Ｗ^２の置換基である炭素数２〜１３のアシルオキシ基としては、アセチルオキシ基、プロピオニルオキシ基及びブチリルオキシ基等が挙げられる。
環Ｗ^１及び環Ｗ^２における、置換基を組み合わせた基としては、炭素数１〜１２のアルコキシ基と炭素数１〜１２のアルキル基とを組み合わせた基、ヒドロキシ基と炭素数１〜１２のアルキル基とを組み合わせた基、炭素数１〜１２のアルコキシ基と炭素数１〜１２のアルコキシ基とを組み合わせた基、炭素数１〜１２のアルコキシ基と炭素数２〜１３のアシル基とを組み合わせた基、炭素数１〜１２のアルコキシ基と炭素数２〜１３のアシルオキシ基とを組み合わせた基、炭素数１〜１２のアルキル基と炭素数６〜１０の芳香族炭化水素基とを組み合わせた基等が挙げられる。
炭素数１〜１２のアルコキシ基と炭素数１〜１２のアルキル基とを組み合わせた基と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等が挙げられる。
ヒドロキシ基と炭素数１〜１２のアルキル基とを組み合わせた基としては、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。
炭素数１〜１２のアルコキシ基と炭素数１〜１２のアルコキシ基とを組み合わせた基としては、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等が挙げられる。
炭素数１〜１２のアルコキシ基と炭素数２〜１３のアシル基とを組み合わせた基とを組み合わせた基とを組み合わせた基としては、メトキシアセチル基、メトキシプロピオニル基、エトキシアセチル基、エトキシプロピオニル基等の炭素数３〜２５のアルコキシアシル基等が挙げられる。
炭素数１〜１２のアルコキシ基と炭素数２〜１３のアシルオキシ基とを組み合わせた基とを組み合わせた基とを組み合わせた基としては、メトキシアセチルオキシ基、メトキシプロピオニルオキシ基、エトキシアセチルオキシ基、エトキシプロピオニルオキシ基等の炭素数２〜２４のアルコキシアシルオキシ基等が挙げられる。
炭素数１〜１２のアルキル基と炭素数６〜１０の芳香族炭化水素基とを組み合わせた基としては、ベンジル基等の炭素数７〜２２のアラルキル基等が挙げられる。
環Ｗ^１及び環Ｗ^２が有する置換基は、ヒドロキシ基、炭素数１〜１２アルコキシ基、炭素数２〜１３のアシルオキシ基、炭素数２〜２４のアルコキシアルキル基、炭素数２〜２４のアルコキシアルコキシ基又はシアノ基であることが好ましく、ヒドロキシ基、炭素数１〜１２アルコキシ基、炭素数２〜１３のアシルオキシ基、炭素数２〜２４のアルコキシアルキル基又は炭素数２〜２４のアルコキシアルコキシ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。 Examples of the alkyl group having 1 to 12 carbon atoms which is a substituent of the ring W ¹ and the ring W ² include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group and a nonyl group. Examples thereof include a decyl group, an undecyl group and a dodecyl group.
Examples of the alkoxy group having 1 to 12 carbon atoms which is a substituent of the ring W ¹ and the ring W ² include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, an octyloxy group and a 2-ethylhexyl. Examples thereof include an oxy group, a nonyloxy group, a decyloxy group, an undecyloxy group and a dodecyloxy group.
Examples of the alicyclic hydrocarbon group having 3 to 12 carbon atoms, which is a substituent of the ring W ¹ and the ring W ^{2, include the groups shown below.} * Is a bond with the ring.

Examples of the aromatic hydrocarbon group having 6 to 10 carbon atoms, which is a substituent of the ring W ¹ and the ring W ^{2, include a phenyl group and a naphthyl group.}
Examples of the alkoxycarbonyl group having 2 to 13 carbon atoms which is a substituent of the ring W ¹ and the ring W ² include a methoxycarbonyl group, an ethoxycarbonyl group, a propoxycarbonyl group, a butoxycarbonyl group, a pentyloxycarbonyl group, and a hexyloxycarbonyl group. Examples thereof include an octyloxycarbonyl group, a 2-ethylhexyloxycarbonyl group, a nonyloxycarbonyl group, a decyloxycarbonyl group, an undecyloxycarbonyl group and a dodecyloxycarbonyl group.
Examples of the acyl group having 2 to 13 carbon atoms which is a substituent of the ring W ¹ and the ring W ^{2 include an acetyl group, a propionyl group and a butyryl group.}
Examples of the acyloxy group having 2 to 13 carbon atoms which is a substituent of the ring W ¹ and the ring W ^{2 include an acetyloxy group, a propionyloxy group and a butyryloxy group.}
In the ring W ¹ and ring W ^2, as a group which combines substituents, a group composed of a combination of an alkyl group having from 1 to 12 alkoxy groups and the carbon atoms of 1 to 12 carbon atoms, hydroxy groups and having 1 to 12 carbon atoms A group combining an alkyl group, an alkoxy group having 1 to 12 carbon atoms and an alkoxy group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms and an acyl group having 2 to 13 carbon atoms. Combined group, a group combining an alkoxy group having 1 to 12 carbon atoms and an acyloxy group having 2 to 13 carbon atoms, an alkyl group having 1 to 12 carbon atoms and an aromatic hydrocarbon group having 6 to 10 carbon atoms in combination. Examples include the group.
Examples of the group combining an alkoxy group having 1 to 12 carbon atoms and an alkyl group having 1 to 12 carbon atoms include a methoxymethyl group, a methoxyethyl group, an ethoxyethyl group, an ethoxymethyl group and the like having 2 carbon atoms. Examples thereof include ~ 24 alkoxyalkyl groups.
Examples of the group in which the hydroxy group and the alkyl group having 1 to 12 carbon atoms are combined include a hydroxyalkyl group having 1 to 12 carbon atoms such as a hydroxymethyl group and a hydroxyethyl group.
Examples of the group in which an alkoxy group having 1 to 12 carbon atoms and an alkoxy group having 1 to 12 carbon atoms are combined include an alkoxyalkoxy group having 2 to 24 carbon atoms such as a methoxymethoxy group, a methoxyethoxy group, an ethoxymethoxy group, and an ethoxyethoxy group. The group and the like can be mentioned.
Examples of the group in which a combination of an alkoxy group having 1 to 12 carbon atoms and an acyl group having 2 to 13 carbon atoms are combined are a methoxyacetyl group, a methoxypropionyl group, an ethoxyacetyl group, or an ethoxypropionyl group. Examples thereof include an alkoxyacyl group having 3 to 25 carbon atoms.
Examples of the group combining a group obtained by combining an alkoxy group having 1 to 12 carbon atoms and an acyloxy group having 2 to 13 carbon atoms include a methoxyacetyloxy group, a methoxypropionyloxy group, and an ethoxyacetyloxy group. Examples thereof include an alkoxyacyloxy group having 2 to 24 carbon atoms such as an ethoxypropionyloxy group.
Examples of the group in which an alkyl group having 1 to 12 carbon atoms and an aromatic hydrocarbon group having 6 to 10 carbon atoms are combined include an aralkyl group having 7 to 22 carbon atoms such as a benzyl group.
The substituents of the rings W ¹ and W ² are a hydroxy group, an alkoxy group having 1 to 12 carbon atoms, an acyloxy group having 2 to 13 carbon atoms, an alkoxyalkyl group having 2 to 24 carbon atoms, and an alkoxy group having 2 to 24 carbon atoms. It is preferably an alkoxy group or a cyano group, and is preferably a hydroxy group, an alkoxy group having 1 to 12 carbon atoms, an acyloxy group having 2 to 13 carbon atoms, an alkoxyalkyl group having 2 to 24 carbon atoms, or an alkoxyalkoxy group having 2 to 24 carbon atoms. Is more preferable, and a hydroxy group is further preferable.

Ring ^{W 1} is preferably an alicyclic hydrocarbon group having 3 to 18 carbon atoms, the ring of formula (W1-1), the ring represented by the formula (w1-2), formula (w1 A ring represented by -3) or a ring represented by the formula (w1-6) is more preferable, and a ring represented by the formula (w1-2) or a ring represented by the formula (w1-6) is used. Is even more preferable.
The ring W ² is preferably an alicyclic hydrocarbon group having 3 to 18 carbon atoms, and is preferably a ring represented by the formula (w1-1), a ring represented by the formula (w1-2), and a formula (w1). A ring represented by -3) or a ring represented by the formula (w1-6) is more preferable, and a ring represented by the formula (w1-1) or a ring represented by the formula (w1-2). Is even more preferable.

The anion in the salt (aa) may have a group represented by the formula (aa1), or 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 is composed of an anion having a group represented by the formula (aa1) and a sulfonate, and a cation. It is more preferable that it is a salt.

［式（ａａ２）中、
Ｑ¹、Ｑ²、Ｌ^b1、Ｘ^a、Ｘ^b、環Ｗ^１及び環Ｗ^２は、上記と同じ意味を表す。］ The salt (aa) having a group represented by the formula (aa1) is preferably a salt having an anion represented by the formula (aa2).

[In equation (aa2),
Q ¹ , Q ² , L ^b1 , X ^a , X ^b , ring W ¹ and ring W ² have the same meanings as described above. ]

The perfluoroalkyl group represented by Q ¹ and Q ^2, a trifluoromethyl group, perfluoroethyl group, perfluoropropyl group, perfluoroisopropyl group, perfluorobutyl group, a perfluoro sec- butyl group, perfluoro-tert- butyl group, perfluoropentyl Examples include groups and perfluorohexyl groups.
Q ¹ and Q ² are each independently a fluorine atom or a trifluoromethyl group is preferable, Q ¹ and Q ² are both fluorine atoms it is more preferable.

Examples of the divalent saturated hydrocarbon group represented by L ^b1 include an alkanediyl group, a monocyclic or polycyclic divalent alicyclic saturated hydrocarbon group, and two or more of these groups. May be a combination of.
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, Nonan-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. Alcandiyl 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, etc. Valuable alicyclic saturated hydrocarbon group;
Polycyclic divalent alicyclic saturated hydrocarbons such as norbornane-1,4-diyl group, norbornane-2,5-diyl group, adamantane-1,5-diyl group, and adamantane-2,6-diyl group. The group etc. can be mentioned.

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。 Any of the formulas (b1-1) to (b1-3) can be used as the group in which _{−CH 2} − contained in the divalent saturated hydrocarbon group represented by L ^{b1 is replaced by −O− or −CO−.} 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 equation (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-bonded or 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, and the saturated hydrocarbon group may be substituted. 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 equation (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-bonded or 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, and the saturated hydrocarbon group may be substituted. 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 b4} and L ^{b5 is 22 or less.}
In equation (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-bonded or 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, and the saturated hydrocarbon group may be substituted. 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 b6} and L ^{b7 is 23 or less.}

In the 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 carbon atoms before the replacement is the saturated hydrocarbon group. The number of carbon atoms in.
Examples of the divalent saturated hydrocarbon group include those similar to the divalent saturated hydrocarbon group of ^{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 divalent saturated hydrocarbon group having 1 to 8 carbon atoms, 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.
Of these, groups represented by the formula (b1-1) or the formula (b1-3) are 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す。
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す。
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す。
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す。
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 the formula (b1-1) include groups represented by the formulas (b1-4) to (b1-8).

In equation (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 equation (b1-5),
L ^b9 represents a divalent saturated hydrocarbon group having 1 to 20 carbon atoms.
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 number of carbon atoms of ^{L b9} and L ^{b10 is 20 or less.}
In equation (b1-6),
L ^b11 represents a divalent saturated hydrocarbon group having 1 to 21 carbon atoms.
L ^b12 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 or a hydroxy group.
However, the total number of carbon atoms of ^{L b11} and L ^{b12 is 21 or less.}
In equation (b1-7),
L ^b13 represents a divalent saturated hydrocarbon group having 1 to 19 carbon atoms.
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 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.
However, the total number of carbon atoms of ^{L b13} , L ^b14 and L ^{b15 is 19 or less.}
In equation (b1-8),
L ^b16 represents a divalent saturated hydrocarbon group having 1 to 18 carbon atoms.
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 divalent saturated hydrocarbon group having 1 to 6 carbon atoms.
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シルオキシ基に置換されていてもよい。該アシ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、該アシ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す。
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シルオキシ基に置換されていてもよい。該アシ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、該アシ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す。
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シルオキシ基に置換されていてもよい。該アシ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、該アシ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 the formula (b1-3) include groups represented by the formulas (b1-9) to (b1-11).

In equation (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 may be substituted with a fluorine atom, a hydroxy group or an acyloxy group. .. The methylene group contained in the acyloxy group may be replaced with an oxygen atom or a carbonyl group, and the hydrogen atom contained in the acyloxy group may be replaced with a hydroxy group.
However, the total number of carbon atoms of ^{L b19} and L ^{b20 is 23 or less.}
In equation (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.
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 may be substituted with a fluorine atom, a hydroxy group or an acyloxy group. .. The methylene group contained in the acyloxy group may be replaced with an oxygen atom or a carbonyl group, and the hydrogen atom contained in the acyloxy group may be replaced with a hydroxy group.
However, the total carbon number of ^{L b21} , L ^b22 and L ^{b23 is 21 or less.}
In equation (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.
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 may be substituted with a fluorine atom, a hydroxy group or an acyloxy group. .. The methylene group contained in the acyloxy group may be replaced with an oxygen atom or a carbonyl group, and the hydrogen atom contained in the acyloxy group may be replaced 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 the hydrogen atom contained in the saturated hydrocarbon group is substituted with an acyloxy group, the number of carbon atoms of the acyloxy group, CO and O in the ester bond The number of carbon atoms of the saturated hydrocarbon group is taken into consideration, including the number of carbon atoms of the saturated hydrocarbon group.

Examples of the acyloxy group include an acetyloxy group, a propionyloxy group, a butyryloxy group, a cyclohexylcarbonyloxy group, an adamantylcarbonyloxy group and the like.
Examples of the acyloxy group having a substituent include an oxoadamantylcarbonyloxy group, a hydroxyadamantylcarbonyloxy group, an oxocyclohexylcarbonyloxy group, a hydroxycyclohexylcarbonyloxy group and the like.

Among the groups represented by the formula (b1-1), the groups represented by the formula (b1-4) include the following.

Among the groups represented by the formula (b1-1), the groups represented by the formula (b1-5) include the following.

Among the groups represented by the formula (b1-1), the groups represented by the formula (b1-6) include the following.

Among the groups represented by the formula (b1-1), the groups represented by the formula (b1-7) include the following.

Among the groups represented by the formula (b1-1), the groups represented by the formula (b1-8) include the following.

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

Among the groups represented by the formula (b1-3), the groups represented by the formula (b1-9) include the following.

Among the groups represented by the formula (b1-3), the groups represented by the formula (b1-10) include the following.

Among the groups represented by the formula (b1-3), the groups represented by the formula (b1-11) include the following.

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

Examples of the anion represented by the formula (aa2) include the following anions. Among them, the anion represented by the formula (aa1-1), the anion represented by the formula (aa1-2), the anion represented by the formula (aa1-8), and the anion represented by the formula (aa1-31). , The anion represented by the formula (aa1-33) and the anion represented by the formula (aa1-41) are preferable.

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 iodine cation, an organic ammonium cation, a benzothiazolium cation, an organic phosphonium cation and the like. Among these, an organic sulfonium cation and an organic iodonium cation are preferable, and an aryl sulfonium cation is more preferable.
Among them, a cation represented by any 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のアシ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 equations (b2-1) to (b2-4),
R ^{b4 to} R ^b6 independently represent 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. It may be substituted, and the hydrogen atom contained in the alicyclic hydrocarbon group is substituted with a halogen atom, an aliphatic hydrocarbon group having 1 to 18 carbon atoms, an acyl 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 may be combined to 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 independently represent a hydroxy group, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.
m2 and n2 each independently represent an integer of 0 to 5.
When m2 is 2 or more, the plurality of R ^b7s may be the same or different, and when n2 is 2 or more, the plurality of R ^b8s may be the same or different.

R ^b9 and R ^b10 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 may be combined to 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 contained in the aliphatic hydrocarbon group. 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 may be an alkoxy group having 1 to 12 carbon atoms or 1 to 12 carbon atoms. It may be substituted with 12 alkylcarbonyloxy groups.
R ^b11 and R ^b12 may be combined to form a ring containing -CH-CO- to which they are bonded, and the methylene group contained in the ring may be an oxygen atom, a sulfinyl group or a carbonyl group. It may be replaced.

R ^{b13 to} R ^b18 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 represent an integer of 0 to 5.
q2 and r2 each independently represent an integer of 0 to 4.
u2 represents 0 or 1.
When o2 is 2 or more, a plurality of R ^b13s are the same or different, when p2 is 2 or more, a plurality of R ^b14s are the same or different, and when q2 is 2 or more, a plurality of R ^b15s are the same or different. when r2 is 2 or more, plural R ^b16 same or different, when s2 is 2 or more, plural R ^b17 same or different, when t2 is 2 or more, plural R ^b18 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。 The aliphatic hydrocarbon group includes 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. Alkyl groups of groups and 2-ethylhexyl groups can be mentioned. In particular, ^{the aliphatic hydrocarbon groups of R b9 to} R ^b12 preferably have 1 to 12 carbon atoms.
The alicyclic hydrocarbon group may be either monocyclic or polycyclic, and the monocyclic alicyclic hydrocarbon group includes a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cyclo. Cycloalkyl groups such as heptyl group, cyclooctyl group and cyclodecyl group can be mentioned. Examples of the polycyclic alicyclic hydrocarbon group include a decahydronaphthyl group, an adamantyl group, a norbornyl group and the following groups.

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

Examples of the alicyclic hydrocarbon group in which the 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, an isobornyl group and the like. Can be mentioned. In the alicyclic hydrocarbon group in which the 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.

Examples of the aromatic hydrocarbon group include a phenyl group, a tolyl group, a xsilyl group, a cumenyl group, a mesityl group, a p-ethylphenyl group, a p-tert-butylphenyl group, a p-cyclohexylphenyl group and a p-adamantylphenyl group. , Biphenylyl group, naphthyl group, phenanthryl group, 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl group and other aryl groups.
When the aromatic hydrocarbon group contains an aliphatic hydrocarbon group or an alicyclic hydrocarbon group, the aliphatic hydrocarbon group having 1 to 18 carbon atoms and the alicyclic hydrocarbon group having 3 to 18 carbon atoms are used. Groups are preferred.
Examples of the aromatic hydrocarbon group in which the hydrogen atom is substituted with an alkoxy group include a p-methoxyphenyl group.
Examples of the aliphatic hydrocarbon group in which the hydrogen atom is substituted with an aromatic hydrocarbon group include an aralkyl group 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 a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, an octyloxy group, a decyloxy group and a dodecyloxy group.
Examples of the acyl 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, and 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 R b4} and R ^b5 together may be a monocyclic, polycyclic, aromatic, non-aromatic, saturated or unsaturated ring. .. Examples of this ring include a ring having 3 to 18 carbon atoms, preferably a ring having 4 to 18 carbon atoms. Further, the ring containing a sulfur atom may be 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 R b9} and R ^b10 together may be any of monocyclic, polycyclic, aromatic, non-aromatic, saturated and unsaturated rings. This ring may be a 3-membered ring to a 12-membered ring, preferably a 3-membered ring to a 7-membered ring. For example, a thiolan-1-ium ring (tetrahydrothiophenium ring), a thian-1-ium ring, a 1,4-oxatian-4-ium ring and the like can be mentioned.
The ^{ring formed by R b11} and R ^b12 together may be monocyclic, polycyclic, aromatic, non-aromatic, saturated or unsaturated. This ring may be 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 cations (b2-1) to cations (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 optionally combine the above-mentioned anions and cations. These anions and cations can be combined arbitrarily.
Examples of the salt (aa) include the salts shown in Tables 1 to 6.
The salt (aa-1) in Table 1 represents the following salt.

Among them, the salt (aa) includes salt (aa-1), salt (aa-2), salt (aa-7), salt (aa-8), salt (aa-9), and salt (aa-10). , Salt (aa-11), salt (aa-12), salt (aa-31), salt (aa-32), salt (aa-37), salt (aa-38), salt (aa-39), Salt (aa-40), salt (aa-41), salt (aa-42), salt (aa-61), salt (aa-62), salt (aa-67), salt (aa-68), salt (Aa-69), salt (aa-70), salt (aa-71), salt (aa-72), salt (aa-91), salt (aa-92), salt (aa-97), salt (aa-69) aa-98), salt (aa-99), salt (aa-100), salt (aa-101), salt (aa-102), salt (aa-121), salt (aa-122), salt (aa) -123), salt (aa-124), salt (aa-125), salt (aa-126), salt (aa-127), salt (aa-128), salt (aa-129), salt (aa-) 131), salt (aa-137), salt (aa-138), salt (aa-139), salt (aa-140), salt (aa-141), salt (aa-142), salt (aa-143) ), Salt (aa-144), salt (aa-145), salt (aa-147), salt (aa-153), salt (aa-154), salt (aa-155), salt (aa-156). , Salt (aa-157), salt (aa-158), salt (aa-159), salt (aa-160), salt (aa-161), salt (aa-163), salt (aa-169), Salt (aa-170), salt (aa-171), salt (aa-172), salt (aa-173), salt (aa-174), salt (aa-175), salt (aa-176), salt (Aa-177) and salt (aa-179) are preferred, salt (aa-1), salt (aa-2), salt (aa-62), salt (aa-68), salt (aa-155), Salt (aa-157), salt (aa-161), and salt (aa-163) are more preferred.

<Manufacturing method of salt (aa)>
From the group represented by the anion represented by the formula (aa2) (L ^b1 represents * -CO-O-, * represents ^{the bonding position with Q 1} Q ² ) and the organic cation (Z ⁺ ). A method for producing a salt (aa) (sometimes referred to as a salt represented by the formula (I1)) will be described.

［式中、全ての符号は、それぞれ前記と同じ意味を表す。］
反応温度は通常、２０℃〜２００℃の範囲内である。 The salt represented by the formula (I1) is obtained by, for example, reacting a salt represented by the formula (I1-a) with a compound represented by the formula (I1-b) in a solvent such as acetonitrile. Can be manufactured.

[In the formula, all the symbols have the same meanings as described above. ]
The reaction temperature is usually in the range of 20 ° C to 200 ° C.

Examples of the compound represented by the formula (I1-a) include compounds represented by the following formula, which can be synthesized according to the method described in JP-A-2012-193160.

［式中、全ての符号は、それぞれ前記と同じ意味を表す。］
反応温度は通常、２０℃〜２００℃の範囲内である。
この反応における酸触媒としては、硫酸、ｐ−トルエンスルホン酸等が挙げられる。
この反応における溶媒としては、クロロホルム、アセトニトリル、ジメチルホルムアミド等が挙げられる。 The compound represented by the formula (I1-b) is obtained by reacting the compound represented by the formula (I1-e) with the compound represented by the formula (I1-f) in a solvent under an acid catalyst. Can be manufactured by

[In the formula, all the symbols have the same meanings as described above. ]
The reaction temperature is usually in the range of 20 ° C to 200 ° C.
Examples of the acid catalyst in this reaction include sulfuric acid, p-toluenesulfonic acid and the like.
Examples of the solvent in this reaction include chloroform, acetonitrile, dimethylformamide and the like.

式（Ｉ１−ｆ）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することができる。

Examples of the compound represented by the formula (I1-e) include compounds represented by the following formula, which can be easily obtained from the market.

Examples of the compound represented by the formula (I1-f) include compounds represented by the following formula, which can be easily obtained from the market.

<Acid generator>
The salt (aa) of the present invention can act as an acid generator in the resist composition. When the salt (a) is used as an acid generator in the resist composition, it may contain one or more kinds of salts (aa), or an acid generator known in the resist field other than the salt (aa). May be further contained.

<Resist composition>
The resist composition contains the salt (aa) of the present invention and a resin having an acid unstable group (hereinafter, may be referred to as "resin (A)"). Here, the "acid-unstable group" means a group having a leaving group, and the leaving group is removed by contact with an acid to form a hydrophilic group (for example, a hydroxy group or a carboxy group).
The resist composition of the present invention may contain an acid generator known in the resist field (hereinafter, may be referred to as "acid generator (B)") as an acid generator other than the salt (aa).
The resist composition preferably contains a quencher (hereinafter sometimes referred to as "quencher (C)") and preferably contains a solvent (hereinafter sometimes referred to as "solvent (E)").

<Resin (A)>
The resin (A) has a structural unit having an acid unstable group (hereinafter, may be referred to as “structural unit (a1)”). The resin (A) preferably further contains a structural unit other than the structural unit (a1). As the structural unit other than the structural unit (a1), a structural unit having no acid-labile group (hereinafter, may be referred to as “structural unit (s)”) and other structural units (hereinafter, “structural unit (t)””. In some cases).

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

［式（２）中、Ｒ^a1’及びＲ^a2’は、それぞれ独立に、水素原子又は炭素数１〜１２の炭化水素基を表し、Ｒ^a3’は、炭素数１〜２０の炭化水素基を表すか、Ｒ^a2’及びＲ^a3’は互いに結合してそれらが結合する炭素原子とともに炭素数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メチレン基は、酸素原子又は硫黄原子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。
＊は結合手を表す。］ <Structural unit (a1)>
The structural unit (a1) is derived from a monomer having an acid unstable group (hereinafter, may be referred to as “monomer (a1)”).
In the resin (A), the acid unstable group contained in the structural unit (a1) is preferably a group represented by the following formula (1) and / or a group represented by the formula (2).

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

[In the 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. Represented, 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 the hydrocarbon group and the divalent heterocyclic group. The methylene group contained in may be replaced with an oxygen atom or a sulfur atom.
X represents an oxygen atom or a sulfur atom.
* Represents a bond. ]

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、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 of 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, an n-octyl group and the like.
The alicyclic hydrocarbon groups of R ^{a1 to} R ^a3 may be either monocyclic or polycyclic. Examples of the monocyclic alicyclic hydrocarbon group include cycloalkyl groups such as cyclopentyl group, cyclohexyl group, cycloheptyl group and cyclooctyl group. Examples of the polycyclic alicyclic hydrocarbon group include a decahydronaphthyl group, an adamantyl group, a norbornyl group and the following groups (* indicates a bond). The alicyclic hydrocarbon groups of R ^{a1 to} R ^a3 have preferably 3 to 16 carbon atoms.

Examples of the group in which the alkyl group and the alicyclic hydrocarbon group are combined include a methylcyclohexyl group, a dimethylcyclohexyl group, a methylnorbornyl group, a cyclohexylmethyl group, an adamantylmethyl group, a norbornylethyl group and the like. ..
na is preferably 0.

^{Examples of -C (R a1} ) (R ^a2 ) (R ^a3 ) in the case where R ^a1 and R a ² 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-. Alkyl adamantan-2-yloxycarbonyl group (in formula (1), R ^a1 , R ^a2 and the carbon atom to which they are bonded form an adamantyl group, and R ^a3 is an alkyl group) and 1- (adamantan-). 1-yl) -1-alkylalkoxycarbonyl group (in the formula (1), R ^a1 and R ^a2 are alkyl groups and R ^a3 is an adamantyl group) and the like.

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 R ^{a1 '~R a3',} an alkyl group, an alicyclic hydrocarbon group, and a group formed by combining an aromatic hydrocarbon group and thereof.
Examples of the alkyl group and the alicyclic hydrocarbon group include the same as above.
Examples of the aromatic hydrocarbon group include a phenyl group, a naphthyl group, an anthryl group, a p-methylphenyl group, a p-tert-butylphenyl group, a p-adamantylphenyl group, a trill group, a xsilyl group, a cumenyl group, a mesityl group and a biphenyl group. Examples thereof include an aryl group such as a group, a phenanthryl group, a 2,6-diethylphenyl group and 2-methyl-6-ethylphenyl.
^{Examples of the} divalent heterocyclic group formed by R ^a2'and R a3'bonding to each other together with the carbon atom and X to which they are bonded include the following groups. * Represents a bond.

Of R ^{a1 'and} R ^a2', it is preferable that at least one is 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 unstable group and an ethylenically unsaturated bond, and more preferably a (meth) acrylic monomer having an acid unstable group.

Among the (meth) acrylic monomers having an acid unstable 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 the structural unit derived from the (meth) acrylic monomer having a group represented by the formula (1), the structural unit represented by the formula (a1-0) is preferably represented by the formula (a1-1). Examples thereof include a structural unit or a structural unit represented by the formula (a1-2). These may be used alone or in combination of two or more. In the present specification, the structural unit represented by the formula (a1-0), the structural unit represented by the formula (a1-1), and the structural unit represented by the formula (a1-2) are each structural unit (a1). −0), structural unit (a1-1) and structural unit (a1-2), monomer for inducing structural unit (a1-0), monomer for inducing structural unit (a1-1) and structural unit (a1-) The monomer that induces 2) may be referred to as a monomer (a1-0), a monomer (a1-1), and a monomer (a1-2), respectively.

［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 equation (a1-0),
L ^a01 represents an oxygen atom or _{^{* -O- (CH 2) k01 -CO}} -O- the stands, k01 represents an integer of 1-7, * represents a bond to a carbonyl group.
R ^a01 represents a hydrogen atom or a methyl group.
R ^a02 , R ^a03, and R ^a04 independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a group combining these groups. ]

^La01 is preferably an oxygen atom or ^* -O- (CH ₂ ) _k01- CO-O-, and more preferably an oxygen atom. k01 is preferably an integer of 1 to 4, more preferably 1.
Examples of the alkyl group of R ^a02 , R ^a03 and R ^a04 , the alicyclic hydrocarbon group and the group combining these groups include the same groups as those mentioned in ^{R a1 to} R ^{a3 of the formula (1).}
The alkyl groups of R ^a02 , R ^a03 and R ^a04 preferably have 6 or less carbon atoms.
The alicyclic hydrocarbon groups of R ^a02 , R ^a03 and R ^a04 preferably have 3 to 8 carbon atoms, and more preferably 3 to 6 carbon atoms.
The group in which the alkyl group and the alicyclic hydrocarbon group are combined preferably has a total carbon number of 18 or less in combination with these alkyl groups and the alicyclic hydrocarbon group. Examples of such a group include a methylcyclohexyl group, a dimethylcyclohexyl group, a methylnorbornyl group and the like.
R ^a02 and R ^a03 are preferably alkyl groups having 1 to 6 carbon atoms, and more preferably methyl groups or ethyl groups.
^Ra04 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.

［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 the formula (a1-1) and the formula (a1-2),
^La1 and ^La2 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 independently represent a hydrogen atom or a methyl group.
R ^a6 and R ^a7 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 them.
m1 represents any integer from 0 to 14.
n1 represents any integer from 0 to 10.
n1'represents an integer of 0 to 3. ]

^La1 and ^La2 are preferably −O− or ^* −O− (CH ₂ ) _{k1 ′} −CO−O−, and more preferably −O−. k1'is an integer of any of 1 to 4, preferably 1.
R ^a4 and R ^a5 are preferably methyl groups.
The alkyl groups of R ^a6 and R ^a7 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. Examples thereof include an n-heptyl group, a 2-ethylhexyl group and an n-octyl group.
The alicyclic hydrocarbon group of R ^a6 and R ^a7 may be either a monocyclic group or a polycyclic group, and examples of the monocyclic alicyclic hydrocarbon group include a cyclopropyl group, a cyclobutyl group and a cyclopentyl group. , Cycloalkyl group, methylcyclohexyl group, dimethylcyclohexyl group, cycloheptyl group, cyclooctyl group, cycloheptyl group, cyclodecyl group and the like. Examples of the polycyclic alicyclic hydrocarbon group include a decahydronaphthyl group, an adamantyl group, a 2-alkyladamantan-2-yl group, a 1- (adamantan-1-yl) alkane-1-yl group, and a norbornyl group. Groups, methylnorbornyl groups, isobornyl groups and the like can be mentioned.
Examples of the group formed by combining the alkyl group of R ^a6 and R ^a7 and the alicyclic hydrocarbon group include an aralkyl group, and a benzyl group, a phenethyl group and the like.
The number of carbon atoms of the alkyl groups of ^{R a6} and R ^{a7 is preferably 6 or less.}
The alicyclic hydrocarbon groups of R ^a6 and R ^a7 have preferably 3 to 8 carbon atoms, more preferably 3 to 6 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, and more preferably 0 or 1.
n1'is preferably 0 or 1, more preferably 1.

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

In the above structural units, structural units in which a methyl group is replaced by a hydrogen atom corresponding to R ^a01 may be mentioned as specific examples of the structural units (a1-0).

Examples of the monomer (a1-1) include the monomers described in JP-A-2010-204646, and preferably any one of the formulas (a1-1-1) to (a1-1-8). Examples thereof include monomers represented by, and more preferably, monomers represented by any of the formulas (a1-1-1) to (a1-1-4).

Examples of the monomer (a1-2) include 1-methylcyclopentane-1-yl (meth) acrylate, 1-ethylcyclopentane-1-yl (meth) acrylate, and 1-methylcyclohexane-1-yl (meth). Acrylate, 1-ethylcyclohexane-1-yl (meth) acrylate, 1-ethylcycloheptane-1-yl (meth) acrylate, 1-ethylcyclooctane-1-yl (meth) acrylate, 1-isopropylcyclopentane-1 -Il (meth) acrylate, 1-isopropylcyclohexane-1-yl (meth) acrylate and the like can be mentioned, and are preferably represented by any of the formulas (a1-2-1) to (a1-2-12). The monomers are more preferably represented by the formula (a1-2-3), the formula (a1-2-4), the formula (a1-2-9) or the formula (a1-2-10). Examples thereof are more preferably monomers represented by the formula (a1-2-3) or the formula (a1-2-9).

When the resin (A) contains a structural unit (a1-0) and / or a structural unit (a1-1) and / or a structural unit (a1-2), the total content of these is the total structure of the resin (A). It is usually 10 to 95 mol%, preferably 15 to 90 mol%, and more preferably 20 to 85 mol% with respect to the total of the units.

［式（ａ１−５）中、
Ｒ^a8は、ハロゲン原子を有してもよい炭素数１〜６のアルキル基、水素原子又はハロゲン原子を表す。
Ｚ^a1は、単結合又は＊−（ＣＨ₂）_h3−ＣＯ−Ｌ⁵⁴−を表し、ｈ３は１〜４の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。 Examples of the structural unit having an acid unstable group include a structural unit represented by the formula (a1-5) (hereinafter, may be referred to as “structural unit (a1-5)”).

[In equation (a1-5),
R ^a8 represents an alkyl group having 1 to 6 carbon atoms, a hydrogen atom or a halogen atom which may have 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 with ^{L 51.}
L ⁵¹ , L ⁵² , L ⁵³ and L ⁵⁴ independently represent -O- or -S-, respectively.
s1 represents an integer of 1 to 3.
s1'represents an integer of 0 to 3.

In the formula (a1-5), R ^a8 represents a hydrogen atom, a methyl group or a trifluoromethyl group.
L ⁵¹ is preferably an oxygen atom.
It is preferable that one of L ⁵² and L ⁵³ is -O- and the other is -S-.
As s1, 1 is preferable.
As s1', any integer of 0 to 2 is preferable.
As Z ^a1 , a single bond or * -CH _2- CO-O- is preferable.

Examples of the monomer for deriving the structural unit (a1-5) include the monomers described in JP-A-2010-61117. Among them, the monomers represented by the formulas (a1-5-1) to (a1-5-2) are preferable, and the monomers represented by the formula (a1-5-1) or the formula (a1-5-2) are preferable. Is more preferable.

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

Further, as the structural unit (a1), the following structural units can also be mentioned.

樹脂（Ａ）が上記構造単位を含む場合、その含有率は、樹脂（Ａ）の全構造単位に対して、１０〜９５モル％が好ましく、１５〜９０モル％がより好ましく、２０〜８５モル％がさらに好ましい。

When the resin (A) contains the above structural units, the content thereof is preferably 10 to 95 mol%, more preferably 15 to 90 mol%, and 20 to 85 mol% with respect to all the structural units of the resin (A). % Is more preferable.

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

<Structural unit having no acid unstable group (s)>
The structural unit (s) is derived from a monomer having no acid-labile group (hereinafter, may be referred to as “monomer (s)”). As the monomer (s) for deriving the structural unit (s), a monomer having no acid unstable 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 unstable group is preferable. A structure having a hydroxy group and no acid-labile group (hereinafter sometimes referred to as "structural unit (a2)") and / or a lactone ring and 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 ray such as a KrF excimer laser (248 nm), an electron beam or EUV (ultraviolet light) is used as an exposure light source, the structural unit (a2) is used. , It is preferable to contain a structural unit (a2) having a phenolic hydroxy group. When an ArF excimer laser (193 nm) or the like is used, it is preferable that the structural unit (a2) includes a structural unit (a2) having an alcoholic hydroxy group, which is represented by the formula (a2-1) described later. It is more preferable to include structural units. As the structural unit (a2), one type may be contained alone, or two or more types may be included.

［式（ａ２−０）中、
Ｒ^a30は、水素原子、ハロゲン原子又はハロゲン原子を有してもよい炭素数１〜６のアルキル基を表す。
Ｒ^a31は、ハロゲン原子、ヒドロキシ基、炭素数１〜６のアルキル基、炭素数１〜６のアルコキシ基、炭素数２〜４のアシル基、炭素数２〜４のアシルオキシ基、アクリロイルオキシ基又はメタクリロイルオキシ基を表す。
ｍａは０〜４のいずれかの整数を表す。ｍａが２以上の整数である場合、複数のＲ^a31は互いに同一であっても異なってもよい。］ Examples of the structural unit (a2) having a phenolic hydroxy group include a structural unit represented by the formula (a2-0) (hereinafter, may be referred to as “structural unit (a2-0)”).

[In equation (a2-0),
^Ra30 represents an alkyl group having 1 to 6 carbon atoms which may have a hydrogen atom, a halogen atom or a halogen atom.
R ^a31 is a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an acyl group having 2 to 4 carbon atoms, an acyloxy group having 2 to 4 carbon atoms, an acryloyloxy group or Represents a methacryloyloxy group.
ma represents any integer from 0 to 4. When ma is an integer of 2 or more, the plurality of Ra ^31s may be the same or different from each other. ]

Examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, an n-pentyl group, an n-hexyl group and the like.
Examples of the halogen atom include a fluorine atom, a chlorine atom and a bromine atom.
Examples of the alkyl group having 1 to 6 carbon atoms which may have a halogen atom include a trifluoromethyl group, a difluoromethyl group, a methyl group, a perfluoroethyl group, a 1,1,1-trifluoroethyl group and 1,1,1. 2,2-Tetrafluoroethyl group, ethyl group, perfluoropropyl group, 1,1,1,2,2-pentafluoropropyl group, propyl group, perfluorobutyl group, 1,1,2,2,3,3 4,4-Octafluorobutyl group, butyl group, perfluoropentyl group, 1,1,1,2,2,3,3,4,4-nonafluoropentyl group, n-pentyl group, n-hexyl group, n -Perfluorohexyl group and the like can be mentioned. R ^a30 is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom, a methyl group or an ethyl group, and even more preferably a hydrogen atom or a methyl group.
^Examples of the alkoxy group of Ra31 include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group and a hexyloxy group. Of these, an alkoxy group having 1 to 4 carbon atoms is preferable, a methoxy group or an ethoxy group is more preferable, and a methoxy group is even more preferable.
Examples of the acyl group include an acetyl group, a propionyl group and a butyryl group.
Examples of the acyloxy group include an acetyloxy group, a propionyloxy group, a butyryloxy group and the like.
The ma is preferably 0, 1 or 2, more preferably 0 or 1, and even more preferably 0.

中でも、式（ａ２−０−１）又は式（ａ２−０−２）で表されるものがより好ましい。
構造単位（ａ２−０）を誘導するモノマーとしては、例えば、特開２０１０−２０４６３４号公報に記載されているモノマーが挙げられる。 Among them, as the structural unit (a2-0) having a phenolic hydroxy group, the structural unit represented by the following is preferable.

Of these, those represented by the formula (a2-0-1) or the formula (a2-0-2) are more preferable.
Examples of the monomer for inducing the structural unit (a2-0) include the monomers described in JP-A-2010-204634.

The resin (A) containing the structural unit (a2) having a phenolic hydroxy group uses a monomer in which the phenolic hydroxy group of the monomer for inducing the structural unit (a2) having a phenolic hydroxy group is protected with a protecting group. It can be produced by carrying out a polymerization reaction and then performing a deprotection treatment. However, when performing the deprotection treatment, it is necessary to carry out the deprotection treatment so as not to significantly impair the acid unstable group of the structural unit (a1). Examples of such a protecting group include an acetyl group and the like.

When the resin (A) has a structural unit (a2-0) having a phenolic hydroxy group, the content thereof is preferably 5 to 95 mol%, preferably 10 to 95 mol%, based on the total structural units of the resin (A). 80 mol% is more preferable, and 15 to 80 mol% is even 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, may be referred to as “structural unit (a2-1)”).

[In equation (a2-1),
^La3 represents −O− or * −O− (CH ₂ ) _k2 −CO−O−.
k2 represents any integer from 1 to 7. * Represents a bond with -CO-.
R ^a14 represents a hydrogen atom or a methyl group.
R ^a15 and R ^a16 independently represent a hydrogen atom, a methyl group or a hydroxy group, respectively.
o1 represents any integer from 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 -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.

アルコール性ヒドロキシ基を有する構造単位（ａ２）を誘導するモノマーとしては、例えば、特開２０１０−２０４６４６号公報に記載されたモノマーが挙げられる。 Examples of the monomer for inducing the structural unit (a2-1) include the monomers described in JP-A-2010-204646. Monomers represented by any of the formulas (a2-1-1) to (a2-1-6) are preferable, and the monomers represented by any of the formulas (a2-1-1) to (a2-1-4) are represented. The structural unit to be formed is more preferable, and the structural unit represented by the formula (a2-1-1) or the formula (a2-1-3) is further preferable.

Examples of the monomer for inducing the structural unit (a2) having an alcoholic hydroxy group include the monomers described in JP-A-2010-204646.

When the resin (A) contains a structural unit (a2) having an alcoholic hydroxy group, the content thereof is usually 1 to 45 mol%, preferably 1 to 45 mol%, based on the total structural units of the resin (A). It is 40 mol%, more preferably 1 to 35 mol%, still more preferably 2 to 20 mol%.

<Structural unit (a3)>
The lactone ring of the structural unit (a3) may be a monocyclic ring such as a β-propiolactone ring, a γ-butyrolactone ring, or a δ-valerolactone ring, or a fused ring of a monocyclic lactone ring and another ring. However, the lactone ring preferably includes a γ-butyrolactone ring, an adamantan lactone ring, or a crosslinked ring containing a γ-butyrolactone ring structure.

［式（ａ３−１）中、
Ｌ^ａ４は、−Ｏ−又は＊−Ｏ−（ＣＨ_２）_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は互いに同一であっても異なってもよい。
式（ａ３−２）中、
Ｌ^ａ５は、−Ｏ−又は＊−Ｏ−（ＣＨ_２）_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は互いに同一であっても異なってもよい。
式（ａ３−３）中、
Ｌ^ａ６は、−Ｏ−又は＊−Ｏ−（ＣＨ_２）_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は互いに同一であっても異なってもよい。
式（ａ３−４）中、
Ｒ^ａ２４は、ハロゲン原子を有してもよい炭素数１〜６のアルキル基、水素原子又はハロゲン原子を表す。
Ｒ^ａ２５は、カルボキシ基、シアノ基又は炭素数１〜４の脂肪族炭化水素基を表す。
Ｌ^ａ７は、−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、互いに独立に、炭素数１〜６のアルカンジイル基を表す。
ｗ１は、０〜８のいずれかの整数を表す。ｗ１が２以上のとき、複数のＲ^ａ２５は互いに同一であってもよく、異なってもよい。］ 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). The resin (A) may contain one of these types alone, or may contain two or more types of the resin (A).

[In equation (a3-1),
^La4 represents a group represented by −O− or * −O− (CH ₂ ) _k3 −CO−O− (k3 represents an integer of any of 1 to 7). * Represents a bond with a carbonyl group.
R ^a18 represents a hydrogen atom or a methyl group.
Ra ²¹ represents an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
p1 represents any integer from 0 to 5. When p1 is 2 or more, the plurality of Ra ^21s may be the same or different from each other.
In formula (a3-2),
^La5 represents a group represented by −O− or * −O− (CH ₂ ) _k3 −CO−O− (k3 represents an integer of any of 1 to 7). * Represents a bond with a carbonyl group.
Ra ¹⁹ represents a hydrogen atom or a methyl group.
^Ra22 represents a carboxy group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
q1 represents any integer from 0 to 3. When q1 is 2 or more, the plurality of Ra ^22s may be the same or different from each other.
In formula (a3-3),
^La6 represents a group represented by −O− or * −O− (CH ₂ ) _k3 −CO−O− (k3 represents an integer of any of 1 to 7). * Represents a bond with a carbonyl group.
R ^a20 represents a hydrogen atom or a methyl group.
^Ra23 represents a carboxy group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
r1 represents any integer from 0 to 3. When r1 is 2 or more, the plurality of Ra ^23s may be the same or different from each other.
In formula (a3-4),
^Ra24 represents an alkyl group having 1 to 6 carbon atoms, a hydrogen atom or a halogen atom which may have a halogen atom.
^Ra25 represents a carboxy group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
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-represented.
* Represents a bond with a carbonyl group.
^La8 and ^La9 represent an alkanediyl group having 1 to 6 carbon atoms independently of each other.
w1 represents any integer from 0 to 8. When w1 is 2 or more, the plurality of Ra ^25s may be the same or different from each other. ]

The aliphatic hydrocarbon groups of 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 of Ra24} include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
^Examples of the alkyl group of R a24 include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group and an n-hexyl group. , Preferably an alkyl group having 1 to 4 carbon atoms, and more preferably a methyl group or an ethyl group.
^{Alkyl groups having a halogen atom of Ra24} include trifluoromethyl group, perfluoroethyl group, perfluoropropyl group, perfluoroisopropyl group, perfluorobutyl group, perfluorosec-butyl group, perfluorotert-butyl group, perfluoropentyl group and perfluoro. Examples thereof include a hexyl group, a trichloromethyl group, a tribromomethyl group, and a triiodomethyl group.

The ^{alkanediyl groups of La8} and ^La9 include methylene group, ethylene group, propane-1,3-diyl group, propane-1,2-diyl group, butane-1,4-diyl group and 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, Examples thereof include 4-diyl group and 2-methylbutane-1,4-diyl group.

In the formula (a3-1) ~ formula ^(a3-3), L a4 ^{~L a6,} independently of one another, preferably -O- or, k3 is a integer of 1 to 4 * -O- ( CH ₂ ) _{A group represented by 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 independent of each other, preferably a carboxy group, a cyano group or a methyl group.
p1, q1 and r1 are independent of each other, preferably an integer of 0 to 2, and more preferably 0 or 1.

（式中、Ｒ^ａ２４、Ｌ^ａ７は、上記と同じ意味を表す。） In the 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, more preferably a hydrogen atom or a methyl group Is.
L ^a7 is preferably -O- or ^{* -O-L} a8 ^-CO-O-, more preferably an _{-O -, - O-CH 2} -CO-O- or _-O-C 2 _{H 4} - It is CO-O-.
^Ra25 is preferably a carboxy group, a cyano group or a methyl group.
w1 is preferably an integer of 0 to 2, more preferably 0 or 1.
In particular, the formula (a3-4) is preferably the formula (a3-4)'.

(In the formula, ^Ra24 and ^La7 have the same meanings as above.)

Examples of the monomer for deriving the structural unit (a3) include the monomers described in JP-A-2010-204646, the monomers described in JP-A-2000-122294, and the monomers described in JP-A-2012-41274. Can be mentioned. The structural unit (a3) includes formulas (a3-1-1) to formulas (a3-1-6), formulas (a3-2-1) to formulas (a3-2-4), and formulas (a3-3-3). 1) The structural unit represented by any of the formulas (a3-3-4) and the formulas (a3-4-1) to (a3-4-12) is preferable, and the formula (a3-1-1), It is represented by any of the formulas (a3-1-2), formulas (a3-2-3) to formulas (a3-2-4) and formulas (a3-4-1) to formulas (a3-4-12). The structural unit is more preferable, and the structural unit represented by any of the formulas (a3-4-1) to (a3-4-12) is more preferable, and the structural units represented by the formulas (a3-4-1) to (a3-4-1) are more preferable. The structural unit represented by any of 4-6) is even more preferable.
The structural unit (a3) may contain one type alone or two or more types. Examples of the structural unit (a3) include the following structural units.

In the structural unit represented by the following formula (a3-4-1) ~ formula (a3-4-12), compound methyl group corresponding to R ^a24 is replaced by a hydrogen atom, the structural unit (a3-4 ) Can be given as a specific example.

When the resin (A) contains the structural unit (a3), the total content thereof is usually 5 to 70 mol%, preferably 10 to 65 mol%, based on all the structural units of the resin (A). , More preferably 10 to 60 mol%.
, The content of each of the structural units represented by the formula (a3-1), the formula (a3-2), the formula (a3-3) and the formula (a3-4) is based on the total structural unit of the resin (A). It is usually 5 to 60 mol%, preferably 5 to 50 mol%, and more preferably 10 to 50 mol%.

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

［式（ａ４−０）中、
Ｒ^５は、水素原子又はメチル基を表す。
Ｌ^５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。
Ｌ^３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５〜１２のペルフルオロシクロアルカンジイル基を表す。
Ｒ^６は、水素原子又はフッ素原子を表す。］ <Structural unit (a4)>
As the halogen atom in the structural unit (a4), a fluorine atom is preferable. Examples of the structural unit (a4) include a structural unit represented by the formula (a4-0).

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

Examples of the aliphatic saturated hydrocarbon group of L ^5, include alkanediyl group having 1 to 4 carbon atoms, e.g., methylene group, ethylene group, propane-1,3-diyl, butane-1,4-diyl group Such as linear alkanediyl group, linear alkanediyl group having an alkyl group (among others, methyl group, ethyl group, etc.) side chain, ethane-1,1-diyl group, propane-1,2 Examples thereof include branched alkanediyl groups such as −diyl group, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group and 2-methylpropane-1,2-diyl group.

The perfluoro alkanediyl group L ^3, difluoromethylene group, a perfluoroalkyl ethylene group, perfluoroethyl fluoro methylene group, perfluoro-1,3-diyl group, perfluoro-1,2-diyl group, 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-3,3-diyl group, perfluorooctane-4,4-diyl group and the like can be mentioned.
The perfluorocycloalkanes diyl group L ^3, perfluoro-cyclohexane diyl group, perfluoro cyclopentanediyl group, perfluoro cycloheptane-diyl group, a perfluoroalkyl adamantane-diyl group and the like.

L ⁵ 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 perfluoroalkanediyl group having 1 to 6 carbon atoms, and more preferably a perfluoroalkanediyl group having 1 to 3 carbon atoms.

Examples of the structural unit (a4-0) include the following.

In the above structural unit, a structural unit in ^{which the methyl group corresponding to R 5} is replaced with a hydrogen atom can also be mentioned as a specific example of the structural unit (a4-0).

［式（ａ４−１）中、
Ｒ^ａ４１は、水素原子又はメチル基を表す。
Ｒ^a42は、置換基を有していてもよい炭素数１〜２０の炭化水素基を表し、該炭化水素基に含まれる−ＣＨ₂−は、−Ｏ−又は−ＣＯ−に置き換わっていてもよい。
Ａ^a41は、置換基を有していてもよい炭素数１〜６のアルカンジイル基又は式（ａ−ｇ１）で表される基を表す。

〔式（ａ−ｇ１）中、
ｓは０又は１を表す。
Ａ^a42及びＡ^a44は、それぞれ独立に、置換基を有していてもよい炭素数１〜５の２価の脂肪族炭化水素基を表す。
Ａ^a43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又は単結合を表す。
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６以下である。〕
ただし、Ａ^a41及びＲ^a42のうち少なくとも一方は、置換基としてハロゲン原子を有する基である。
＊、＊＊は結合手であり、＊が−Ｏ−ＣＯ−Ｒ^ａ４２との結合手である。］
ｓは０が好ましい。 Examples of the structural unit (a4) include a structural unit represented by the formula (a4-1).

[In equation (a4-1),
R ^a41 represents a hydrogen atom or a methyl group.
R ^a42 represents a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, and −CH ₂ − contained in the hydrocarbon group may be replaced with −O− or −CO−. good.
A ^a41 represents an alkanediyl group having 1 to 6 carbon atoms which may have a substituent or a group represented by the formula (ag1).

[In the formula (ag1),
s represents 0 or 1.
A ^a42 and A ^a44 each independently represent a divalent aliphatic hydrocarbon group having 1 to 5 carbon atoms which may have a substituent.
A ^a43 represents a divalent aliphatic hydrocarbon group or a single bond having 1 to 5 carbon atoms which may have a substituent.
X ^a41 and X ^a42 independently represent -O-, -CO-, -CO-O- or -O-CO-, respectively.
However, the total number of carbon atoms of ^{A a42} , A ^a43 , A ^a44 , X ^a41 and X ^{a42 is 6 or less.} ]
However, ^{at least one of A a41} and R ^a42 is a group having a halogen atom as a substituent.
* And ** are bonds, and * is a bond with -O-CO-R ^a42 . ]
s is preferably 0.

芳香族炭化水素基としては、例えば、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等が挙げられる。 ^Examples of the hydrocarbon group of R a42 include a chain type and a ring type aliphatic hydrocarbon group, an aromatic hydrocarbon group, and a group formed by combining these groups. Chain-type aliphatic hydrocarbon groups include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, decyl group, dodecyl group, hexadecyl group, pentadecyl group and hexyldecyl group. , Alkyl groups such as heptadecyl group and octadecyl group. Cyclic alicyclic aliphatic hydrocarbon groups include cycloalkyl groups such as cyclopentyl group, cyclohexyl group, cycloheptyl group and cyclooctyl group; decahydronaphthyl group, adamantyl group, norbornyl group and the following groups (*). Represents a bond.) And other polycyclic alicyclic hydrocarbon groups can be mentioned.

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。
＊はカルボニル基との結合手を表す。］ ^Examples of the substituent of R a42 include a halogen atom and a group represented by the formula (ag3). Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and a fluorine atom is preferable.

[In the formula (ag3),
X ^a43 represents an oxygen atom, a carbonyl group, a carbonyloxy group or an oxycarbonyl group.
A ^a45 represents an aliphatic hydrocarbon group having 1 to 17 carbon atoms having at least one halogen atom.
* Represents a bond with a carbonyl group. ]

Examples of the aliphatic hydrocarbon group of A ^{a45 include} the same groups as those exemplified in ^{R a42.}
R ^a42 is preferably an aliphatic hydrocarbon group which may have a halogen atom, and more preferably an alkyl group having a halogen atom and / or an aliphatic hydrocarbon group having a group represented by the formula (ag3). ..

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 further preferably having a carbon number of carbons. It is a perfluoroalkyl group of 1 to 6, and particularly preferably a perfluoroalkyl group having 1 to 3 carbon atoms. 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 (ag3), the aliphatic hydrocarbon includes the number of carbon atoms contained in the group represented by the formula (ag3). The total carbon number of the group is preferably 15 or less, more preferably 12 or less. When the group represented by the formula (ag3) is used as a substituent, the number thereof is preferably one.

［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。］ When R ^a42 is an aliphatic hydrocarbon group having a group represented by the formula ( ^{ag3), R a42} is more preferably a group represented by the formula (ag2).

[In the formula (ag2),
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. ]

The aliphatic hydrocarbon group of A ^a46 preferably has 1 to 6 carbon atoms, more preferably 1 to 3 carbon atoms.
The aliphatic hydrocarbon group of A ^a47 preferably has 4 to 15 carbon atoms, more preferably 5 to 12 carbon atoms, and even more preferably a cyclohexyl group or an adamantyl group.

Examples of the group represented by the formula (ag2) include the following groups.

The ^{alkanediyl group of A a41} includes a methylene group, an ethylene group, a propane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, and a hexane-1,6-diyl group. Linear alkanediyl groups such as propane-1,2-diyl group, butane-1,3-diyl group, 2-methylpropane-1,2-diyl group, 1-methylbutane-1,4-diyl group, etc. Examples thereof 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 further preferably an ethylene group.

^{The aliphatic hydrocarbon groups of A a42} , A ^a43 and A ^{a44 in} the group represented by the formula (a-g1) (hereinafter, sometimes referred to as "group (ag1)") include a methylene group and an ethylene group. , Propane-1,3-diyl group, propane-1,2-diyl group, butane-1,4-diyl group, 1-methylpropane-1,3-diyl group, 2-methylpropane-1,3-diyl group Examples include a group, a 2-methylpropane-1,2-diyl group and the like. Examples of these substituents include a hydroxy group and an alkoxy group having 1 to 6 carbon atoms.

^{Examples of the group (ag1) in} which X a42 is an oxygen atom include the following groups. In the following examples, * and ** represent the bond, respectively, and ** is the bond with -O-CO-R ^a42 .

^{Examples of the group (ag1) in} which X a42 is a carbonyl group include the following groups.

^{Examples of the group (ag1) in} which X a42 is a carbonyloxy group include the following groups.

^{Examples of the group (ag1) in} which X a42 is an oxycarbonyl group include the following groups.

［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), the structural unit represented by the formula (a4-2) and the formula (a4-3) is preferable.

[In equation (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 hydrocarbon group having 1 to 10 carbon atoms having a fluorine atom. ]

The ^{alkanediyl group of A f1} includes 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. , Hexine-1,6-diyl group and other linear alkanediyl groups; 1-methylpropane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2 Examples thereof include branched alkanediyl groups such as −diyl group, 1-methylbutane-1,4-diyl group and 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 type, a cyclic type and a group formed by a combination thereof. As the aliphatic hydrocarbon group, an alkyl group and an alicyclic hydrocarbon group are preferable.
Alkyl groups 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 -Ethylhexyl groups can be mentioned.
The alicyclic hydrocarbon group may be either a monocyclic group or a polycyclic group, and the monocyclic alicyclic hydrocarbon group includes a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group and a methylcyclohexyl group. , Cycloalkyl groups such as dimethylcyclohexyl group, cycloheptyl group, cyclooctyl group, cycloheptyl group and cyclodecyl group. Examples of the polycyclic alicyclic hydrocarbon group include a decahydronaphthyl group, an adamantyl group, a 2-alkyladamantan-2-yl group, a 1- (adamantan-1-yl) alkane-1-yl group, and a norbornyl group. Examples thereof include a methylnorbornyl group and an isobornyl group.

Examples of the hydrocarbon group having a fluorine atom of R ^f2 include an alkyl group having a fluorine atom and an alicyclic hydrocarbon group having a fluorine atom.
Specifically, 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, and a 2,2,2-trifluoroethyl group. Perfluoroethyl group, 1,1,2,2-tetrafluoropropyl group, 1,1,2,2,3,3-hexafluoropropyl group, perfluoroethylmethyl group, 1- (trifluoromethyl) -1,2 , 2,2-Tetrafluoroethyl group, Perfluoropropyl group, 1,1,2,2-Tetrafluorobutyl group, 1,1,2,2,3,3-Hexafluorobutyl group, 1,1,2, 2,3,3,4,5-octafluorobutyl group, perfluorobutyl group, 1,1-bis (trifluoro) methyl-2,2,2-trifluoroethyl group, 2- (perfluoropropyl) ethyl group, 1,1,2,2,3,3,4,5-octafluoropentyl group, perfluoropentyl group, 1,1,2,2,3,3,4,5,5-decafluoropentyl group, 1,1-bis (trifluoromethyl) -2,2,3,3,3-pentafluoropropyl group, perfluoropentyl group, 2- (perfluorobutyl) ethyl group, 1,1,2,2,3,3 , 4,4,5,5-decafluorohexyl group, 1,1,2,2,3,3,4,5,5,6,6-dodecafluorohexyl group, perfluoropentylmethyl group and perfluorohexyl Fluoroalkyl groups such as groups can be mentioned.
Examples of the alicyclic hydrocarbon group having a fluorine atom include a cycloalkyl fluoride group such as a perfluorocyclohexyl group and a perfluoroadamantyl group.

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

［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 equation (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 of A f11 include the same groups as the alkanediyl group of A ^f1 .

The aliphatic hydrocarbon group of A ^f13 includes either a chain type or a cyclic type, and a divalent aliphatic hydrocarbon group formed by combining them. This 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 an alkanediyl group such as a methylene group, an ethylene group, a propanediyl group, a butanjiyl group and a pentandiyl group; a difluoromethylene group and a perfluoroethylene group. Examples thereof include a perfluoroalkandyl group such as a group, a perfluoropropanediyl group, a perfluorobutandyl group and a 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 adamantandiyl group, a norbornanediyl group, and a perfluoroadamantandiyl group.

The aliphatic hydrocarbon group of A ^f14 includes either a chain type or a cyclic type, and an aliphatic hydrocarbon group formed by combining them. This 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.
Chain-type aliphatic hydrocarbon groups that may have a fluorine atom include trifluoromethyl group, difluoromethyl group, methyl group, perfluoroethyl group, 1,1,1-trifluoroethyl group, and 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, Examples thereof include a heptyl group, a perfluoroheptyl group, an octyl group and a perfluorooctyl group.
The cyclic aliphatic hydrocarbon group which may have a fluorine atom may be a group containing either a monocyclic or polycyclic group. 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, a perfluoroadamantylmethyl group and the like.

In the formula (a4-3), examples of ^{A f11,} ethylene group is preferable.
The aliphatic hydrocarbon group of A ^f13 preferably has 1 to 6 carbon atoms, and more preferably 2 to 3 carbon atoms.
The aliphatic hydrocarbon group of A ^f14 preferably has 3 to 12 carbon atoms, and more preferably 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 structural units represented by the formulas (a4-1-1) to (a4-1-22).

Examples of the structural unit represented by the formula (a4-3) include structural units represented by the formulas (a4-1'-1) to (a4-1'-22).

［式（ａ４−４）中、
Ｒ^f21は、水素原子又はメチル基を表す。
Ａ^f21は、−（ＣＨ_２）_ｊ１−、−（ＣＨ_２）_ｊ２−Ｏ−（ＣＨ_２）_ｊ３−又は−（ＣＨ_２）_ｊ４−ＣＯ−Ｏ−（ＣＨ_２）_ｊ５−を表す。
ｊ１〜ｊ５は、それぞれ独立に、１〜６のいずれかの整数を表す。
Ｒ^f22は、フッ素原子を有する炭素数１〜１０の炭化水素基を表す。］ The structural unit (a4) may be a structural unit represented by the formula (a4-4).

[In equation (a4-4),
R ^f21 represents a hydrogen atom or a methyl group.
A ^f21 represents − (CH ₂ ) _j1 −, − (CH ₂ ) _j2 −O− (CH ₂ ) _j3 − or − (CH ₂ ) _j4 −CO−O− (CH ₂ ) _j5- .
j1 to j5 each independently represent an integer of 1 to 6.
R ^f22 represents a hydrocarbon group having 1 to 10 carbon atoms having a fluorine atom. ]

^Examples of the hydrocarbon group having a fluorine atom of R ^{f22 include the same hydrocarbon group as R f2} in the formula (a4-2). R ^f22 is preferably an alkyl group having 1 to 10 carbon atoms having a fluorine atom or an alicyclic hydrocarbon group having 1 to 10 carbon atoms having a fluorine atom, and an alkyl group having 1 to 10 carbon atoms having a fluorine atom is more preferable. Preferably, an alkyl group having 1 to 6 carbon atoms having a fluorine atom is more preferable.

In the formula (a4-4), as A ^f21 , − (CH ₂ ) _j1 − is preferable, an ethylene group or a methylene group is more preferable, and a methylene group is further preferable.

Examples of the structural unit represented by the formula (a4-4) include the following structural units.

When the resin (A) has a structural unit (a4), the content thereof is preferably 1 to 20 mol%, more preferably 2 to 15 mol%, and 3) with respect to all the structural units of the resin (A). 10 mol% is more preferable.

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

[In equation (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 the hydrogen atom contained in the alicyclic hydrocarbon group is substituted with an aliphatic hydrocarbon group or a hydroxy group having 1 to 8 carbon atoms. You may. However, ^{the hydrogen atom bonded to the carbon atom at the bonding position with L 55} is not replaced by an aliphatic hydrocarbon group having 1 to 8 carbon atoms.
L ⁵⁵ represents a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, 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 of R ⁵² may be either a monocyclic or polycyclic group. 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 a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a pentyl group and a hexyl group. , Alkyl groups such as octyl group and 2-ethylhexyl group.
Examples of the alicyclic hydrocarbon group having a substituent include a 3-hydroxyadamantyl group and a 3-methyladamantyl group.
R ⁵² is preferably an unsubstituted alicyclic hydrocarbon group having 3 to 18 carbon atoms, and more preferably an adamantyl group, a norbornyl group or a cyclohexyl group.

Examples of the divalent saturated hydrocarbon group of L ⁵⁵ include a divalent aliphatic saturated hydrocarbon group and a divalent alicyclic saturated hydrocarbon group, and a divalent aliphatic saturated hydrocarbon group is preferable. ..
Examples of the divalent aliphatic saturated hydrocarbon group include an alkanediyl group such as a methylene group, an ethylene group, a propanediyl group, a butanjiyl group and a pentandiyl group.
The divalent alicyclic saturated hydrocarbon group may be either monocyclic or polycyclic. Examples of the monocyclic alicyclic saturated hydrocarbon group include a cycloalkanediyl group such as a cyclopentanediyl group and a cyclohexanediyl group. Examples of the polycyclic divalent alicyclic saturated hydrocarbon group include an adamantandiyl 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^x1及びＬ^x2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、互いに独立に、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 the 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 number of carbon atoms 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 number of carbon atoms of ^{L x1} and L ^{x2 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 number of carbon atoms of ^{L x5} , L ^x6 and L ^{x7 is 15 or less.}
In formula (L1-4),
L ^x8 and L ^x9 represent a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 12 carbon atoms independently of each other.
W ^{x 1} represents a divalent alicyclic saturated hydrocarbon group having 3 to 15 carbon atoms.
However, the total number of carbon atoms of ^{L x8} , L ^x9 and W ^{x1 is 15 or less.}

L ^{x 1} is preferably a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, and 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, and more preferably a single bond.
L ^x3 is preferably a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms.
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, and 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, and 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, and 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, and more preferably a single bond or a methylene group.
W ^{x 1} is preferably a divalent alicyclic saturated hydrocarbon group having 3 to 10 carbon atoms, and more preferably a cyclohexanediyl group or an adamantandiyl group.

Examples of the group represented by the formula (L1-1) include the divalent groups shown below.

Examples of the group represented by the formula (L1-2) include the following divalent groups.

Examples of the group represented by the formula (L1-3) include the divalent groups shown below.

Examples of the group represented by the formula (L1-4) include the divalent groups shown below.

L ⁵⁵ is preferably a single bond, a methylene group, an ethylene group or a group represented by the formula (L1-1), and more preferably a single bond or a group represented by the formula (L1-1). ..

Examples of the structural unit (a5-1) include the following.

When the resin (A) has a structural unit (a5), the content thereof is preferably 1 to 30 mol%, more preferably 2 to 20 mol%, and 3) with respect to all the structural units of the resin (A). ~ 15 mol% is more preferred.

The resin (A) may have a structural unit other than the above-mentioned structural unit, and examples of such a structural unit include structural units well known in the art.

The resin (A) is preferably a resin composed of a structural unit (a1) and a structural unit (s), that is, a copolymer of a monomer (a1) and a monomer (s).
The structural unit (a1) is preferably at least one selected from the structural unit (a1-1) and the structural unit (a1-2) (preferably the structural unit having a cyclohexyl group and a cyclopentyl group), and more preferably the structural unit (a1). It is at least two kinds selected from a1-1) or a structural unit (a1-1) and a structural unit (a1-2) (preferably the structural unit having a cyclohexyl group and a cyclopentyl group).
The structural unit (s) is preferably at least one of the structural unit (a2) and the structural unit (a3). The structural unit (a2) is preferably a structural unit represented by the formula (a2-1). The structural unit (a3) is preferably a structural unit represented by the formulas (a3-1-1) to (a3-1-4), and the formulas (a3-2-1) to (a3-2-4). And at least one selected from the structural units represented by the formulas (a3-4-1) to (a3-4-2).

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, a radical polymerization method) using a monomer for inducing these structural units. can do. The content of each structural unit of the resin (A) can be adjusted by adjusting the amount of the monomer used for the polymerization.
The weight average molecular weight of the resin (A) is preferably 2,000 or more (more preferably 2,500 or more, still more preferably 3,000 or more) and 50,000 or less (more preferably 30,000 or less, still more preferable. Is 15,000 or less). In the present specification, the weight average molecular weight is a value obtained by gel permeation chromatography under the conditions described in Examples.

<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 a structural unit (t).

As the resin other than the resin (A), a resin containing a structural unit (a4) (however, it does not contain the structural unit (a1); hereinafter may be referred to as “resin (X)”) is preferable. In the resin (X), the content of the structural unit (a4) is preferably 40 mol% or more, more preferably 45 mol% or more, still more preferably 50 mol% or more, based on all the structural units of the resin (X). ..
Examples of the structural unit that the resin (X) may further include include a structural unit (a2), a structural unit (a3), and a structural unit derived from other known monomers.
The weight average molecular weight of the resin (X) is preferably 8,000 or more (more preferably 10,000 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 of the resin (A).
When the resist composition contains the resin (X), the content thereof is preferably 1 to 60 parts by mass, more preferably 1 to 50 parts by mass, and further, with respect to 100 parts by mass of the resin (A). It is preferably 1 to 40 parts by mass, and particularly preferably 2 to 30 parts by mass.

The total content of the resin (A) and the resin other than the resin (A) is preferably 80% by mass or more and 99% by mass or less with respect to the solid content of the resist composition. The solid content of the resist composition and the content of the resin relative to the solid content can be measured by a known analytical means such as liquid chromatography or gas chromatography.

<Acid generator>
The acid generator (B) may be an ionic acid generator or a nonionic acid generator. Preferably, it is an ionic acid generator. Examples of the ionic acid generator include an ionic acid generator composed of a combination of a known cation and a known anion.

Examples of the acid generator (B) include organic sulfonium salts, and examples thereof include acid generators described in JP2013-68914, JP2013-3155, JP2013-1905 and the like. Specific examples thereof include salts represented by any of the formulas (B1-1) to (B1-40). Of these, those containing an arylsulfonium cation are preferable, and formulas (B1-1), formulas (B1-2), formulas (B1-3), formulas (B1-6), formulas (B1-7), and formulas (B1-11) are preferable. ), Equation (B1-12), Equation (B1-13), Equation (B1-14), Equation (B1-20), Equation (B1-21), Equation (B1-22), Equation (B1-23). , Equation (B1-24), Equation (B1-25), Equation (B1-26), Equation (B1-29), Equation (B1-31), Equation (B1-32), Equation (B1-33), Any of formula (B1-34), formula (B1-35), formula (B1-36), formula (B1-37), formula (B1-38), formula (B1-39) or formula (B1-40) The salt represented by is more preferable.

In the resist composition of the present invention, the content of the salt (aa) is preferably 0.1% by mass or more and 35% by mass or less, and 0.5% by mass or more and 30% by mass or less, based on the solid content of the resist composition. The following is more preferable, and 1% by mass or more and 25% by mass or less is further preferable.
When the acid generator (B) is contained, the total content of the salt (aa) and the acid generator (B) is preferably 1.5 parts by mass or more with respect to 100 parts by mass of the resin (A). (More preferably 3 parts by mass or more), preferably 40 parts by mass or less (more preferably 35 parts by mass or less).

The content of the acid generator (B) is preferably 1 part by mass or more (more preferably 3 parts by mass or more), preferably 30 parts by mass or less (more preferably 25 parts by mass) with respect to 100 parts by mass of the resin (A). (Below). The resist composition of the present invention may contain one kind of the acid generator (B) alone, or may contain a plurality of kinds.
In the resist composition of the present invention, the content ratio (mass ratio; salt (aa): acid generator (B)) of the salt (aa) to the acid generator (B) is usually 1:99 to 100. : 0, preferably 1:99 to 99: 1, more preferably 2:98 to 98: 2, and even more preferably 5:95 to 95: 5.

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

Examples of the solvent (E) include glycol ether esters such as ethyl cellosolve acetate, methyl cellosolve acetate and propylene glycol monomethyl ether acetate; glycol ethers such as propylene glycol monomethyl ether; ethyl lactate, butyl acetate, amyl acetate and ethyl pyruvate. Esters; ketones such as acetone, methylisobutylketone, 2-heptanone and cyclohexanone; cyclic esters such as γ-butyrolactone; and the like. One type of solvent (E) may be contained alone, or two or more types may be contained.

<Quencher (C)>
Examples of the quencher (C) include a basic nitrogen-containing organic compound or a salt that generates an acid having a weaker acidity than the acid generated from an acid generator. The content of the quencher (C) is preferably about 0.01 to 5% by mass based on the solid content of the resist composition.
Examples of the basic nitrogen-containing organic compound include amine and ammonium salts. Examples of amines include aliphatic amines and aromatic amines. Aliphatic amines include primary amines, secondary amines and tertiary amines.

Examples of amines include 1-naphthylamine, 2-naphthylamine, aniline, diisopropylaniline, 2-,3- or 4-methylaniline, 4-nitroaniline, N-methylaniline, N, N-dimethylaniline, diphenylamine, hexylamine, Heptylamine, octylamine, nonylamine, decylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, triethylamine, trimethylamine, tripropylamine, tributylamine, trypentylamine, trihexylamine, tri Heptylamine, trioctylamine, trinonylamine, tridecylamine, methyldibutylamine, methyldipentylamine, methyldihexylamine, methyldicyclohexylamine, methyldiheptylamine, methyldioctylamine, methyldinonylamine, methyldidecylamine, Ethyldibutylamine, ethyldipentylamine, ethyldihexylamine, ethyldiheptylamine, ethyldioctylamine, ethyldinonylamine, ethyldidecylamine, dicyclohexylmethylamine, tris [2- (2-methoxyethoxy) ethyl] amine, tri Isopropanolamine, ethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4'-diamino-1,2-diphenylethane, 4,4'-diamino-3,3'-dimethyldiphenylmethane, 4,4'-diamino-3 , 3'-diethyldiphenylmethane, 2,2'-methylenebisaniline, imidazole, 4-methylimidazole, pyridine, 4-methylpyridine, 1,2-di (2-pyridyl) ethane, 1,2-di (4-di) Pyridyl) ethane, 1,2-di (2-pyridyl) ethene, 1,2-di (4-pyridyl) ethane, 1,3-di (4-pyridyl) propane, 1,2-di (4-pyridyloxy) ) Ethan, di (2-pyridyl) ketone, 4,4'-dipyridyl sulfide, 4,4'-dipyridyl disulfide, 2,2'-dipyridylamine, 2,2'-dipicorylamine, bipyridine and the like. Diisopropylaniline is preferable, and 2,6-diisopropylaniline is more preferable.

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

<Salt that generates acid with weak acidity>
The acidity of a salt that produces an acid that is weaker than the acid generated by the salt (aa) and the acid generator (B) is indicated by the acid dissociation constant (pKa). A salt that generates an acid having a weaker acidity than the acid generated from the salt (aa) and the acid generator (B) usually has an acid dissociation constant of -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 weaker acidity than the acid generated from the salt (aa) and the acid generator (B) include a salt represented by the following formula and a compound represented by the formula (D) (hereinafter, weak acid). Intramolecular salt (D),), and JP-A-2012-229206, JP-A-2012-6908, JP-A-2012-72109, JP-A-2011-39502 and JP-A-2011- Examples thereof include salts described in Japanese Patent Application Laid-Open No. 191745. It is preferably a salt having a weak acid content represented by the formula (D).

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

[In formula (D),
R ^D1 and R ^D2 independently have a monovalent hydrocarbon group having 1 to 12 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an acyl group having 2 to 7 carbon atoms, and an acyloxy group having 2 to 7 carbon atoms. Represents an alkoxycarbonyl group, a nitro group or a halogen atom having 2 to 7 carbon atoms.
m'and n'independently represent an integer of 0 to 4, and when m'is 2 or more, a plurality of ^RD1s are the same or different, and when n'is 2 or more, a plurality of RD1s are the same or different. R ^D2 is the same or different. ]

^{The hydrocarbon groups of RD1} and ^RD2 in the compound represented by the formula (D) include a monovalent aliphatic hydrocarbon group, a monovalent alicyclic hydrocarbon group, and a monovalent aromatic hydrocarbon group. Examples thereof include groups formed by combining these.
Examples of the monovalent aliphatic hydrocarbon group include alkyl groups such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, t-butyl group, pentyl group, hexyl group and nonyl group.
The monovalent alicyclic hydrocarbon group may be either a monocyclic or polycyclic group, and may be saturated or unsaturated. Examples thereof include cycloalkyl groups such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cyclononyl group and cyclododecyl group, norbonyl group and adamantyl group.
Examples of the monovalent aromatic hydrocarbon group include phenyl group, 1-naphthyl group, 2-naphthyl group, 2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 4-ethylphenyl group and 4-. Propylphenyl group, 4-isopropylphenyl group, 4-butylphenyl group, 4-t-butylphenyl group, 4-hexylphenyl group, 4-cyclohexylphenyl group, anthryl group, p-adamantylphenyl group, trill group, xsilyl group , Cumenyl group, mesityl group, biphenyl group, phenanthryl group, aryl group such as 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl and the like.
Examples of the group formed by combining these groups include an alkyl-cycloalkyl group, a cycloalkyl-alkyl group, and an aralkyl group (for example, a phenylmethyl group, a 1-phenylethyl group, a 2-phenylethyl group, and a 1-phenyl-1 group. -Propyl group, 1-phenyl-2-propyl group, 2-phenyl-2-propyl group, 3-phenyl-1-propyl group, 4-phenyl-1-butyl group, 5-phenyl-1-pentyl group, 6 −Phenyl-1-hexyl group, etc.) and the like.

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

In the formula (D), ^RD1 and ^RD2 independently have an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and 2 carbon atoms, respectively. Preferred are an acyl group of ~ 4; an acyloxy group having 2-4 carbon atoms, an alkoxycarbonyl group having 2-4 carbon atoms, a nitro group or a halogen atom.
m'and n'are each independently preferably an integer of 0 to 2, and more preferably 0.

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

The weak acid intramolecular salt (D) can be produced by the method described in "Tetrahedron Vol. 45, No. 19, p6281-6296". Further, as the weak acid intramolecular salt (D), a commercially available compound can be used.

The content of the salt that generates a weakly acidic acid, for example, the weak acid intramolecular salt (D), is preferably 0.01 to 5% by mass, more preferably 0.01, based on the solid content of the resist composition. ~ 3% by mass.

<Other ingredients>
The resist composition of the present invention may contain components other than the above-mentioned components (hereinafter, may be referred to as "other components (F)"), if necessary. The other component (F) is not particularly limited, and additives known in the resist field, such as sensitizers, dissolution inhibitors, surfactants, stabilizers, dyes, and the like can be used.

<Preparation of resist composition>
The resist composition of the present invention comprises a resin (A), a salt (aa) of the present invention, a resin other than the resin (A) used as needed, an acid generator (B), a solvent (E), and a citric acid. It can be prepared by mixing a salt that generates a weakly acidic acid such as char (C) and a weak acid intramolecular salt (D) and other components (F). The mixing order is arbitrary and is not particularly limited. The temperature at the time of mixing can be selected from 10 to 40 ° C., depending on the type of resin or the like and the solubility of the resin or the like in the solvent (E). The 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 or the like 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.

<Manufacturing method of resist pattern>
The method for producing a resist pattern of the present invention is
(1) A step of applying the resist composition of the present invention on a substrate,
(2) A step of drying the applied composition to form a composition layer,
(3) Step of exposing the composition layer,
It includes (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 device such as a spin coater. Examples of the substrate include an inorganic substrate such as a silicon wafer. The substrate may be washed before the resist composition is applied, 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 prebaking), or by 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 at the time of vacuum drying is preferably about 1~1.0 × 10 ⁵ Pa.

The obtained composition layer is usually exposed to an exposure machine. The exposure machine may be an immersion exposure machine. The exposure light source includes a KrF excimer laser (wavelength 248 nm), an ArF excimer laser (wavelength 193 nm), an F ₂ excimer laser (wavelength 157 nm) that emits laser light in the ultraviolet region, and a solid-state laser light source (YAG or semiconductor laser). Etc.), and various ones such as those that radiate harmonic laser light in the far ultraviolet region or vacuum ultraviolet region by wavelength conversion, those that irradiate electron beams, super-ultraviolet light (EUV), etc. are used. Can be done. In addition, in this specification, irradiating these radiations may be generically referred to as "exposure". At the time of exposure, the exposure is usually performed through a mask corresponding to the required pattern. When the exposure light source is an electron beam, the exposure may be performed by drawing directly without using a mask.

The exposed composition layer is heat treated (so-called post-exposure bake) to promote the deprotection reaction at the acid-labile group. The heating temperature is usually about 50 to 200 ° C, preferably about 70 to 150 ° C.

The composition layer after heating is usually developed using a developing solution using a developing device. Examples of the developing method include a dip method, a paddle method, a spray method, and a dynamic dispense method. The developing temperature is preferably, for example, 5 to 60 ° C., and the developing time is preferably, for example, 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 the resist composition of the present invention, an alkaline developer is used as the developer. The alkaline developer may be any alkaline aqueous solution used in this field. For example, an aqueous solution of tetramethylammonium hydroxide or (2-hydroxyethyl) trimethylammonium hydroxide (commonly known as choline) can be mentioned. The alkaline developer may contain a surfactant.
After development, it is preferable to wash the resist pattern with ultrapure water and then remove the substrate and water remaining on the pattern.

When a negative resist pattern is produced from the resist composition of the present invention, a developer containing an organic solvent (hereinafter, may be referred to as "organic developer") is used as the developer.
Examples of the organic solvent contained in the organic developing solution include a ketone solvent such as 2-hexanone and 2-heptanone; a glycol ether ester solvent such as propylene glycol monomethyl ether acetate; an ester solvent such as butyl acetate; and a glycol such as propylene glycol monomethyl ether. Examples include ether solvents; amide solvents such as N and N-dimethylacetamide; aromatic hydrocarbon solvents such as anisole.
The content of the organic solvent in the organic developer 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 further preferably substantially only the organic solvent.
Among them, as the organic developer, a developer containing butyl acetate and / or 2-heptanone is preferable. The total content of butyl acetate and 2-heptanone in the organic developer is preferably 50% by mass or more and 100% by mass or less, more preferably 90% by mass or more and 100% by mass or less, and substantially butyl acetate and / or 2 -It is even more preferable that it is only heptanone.
The organic developer may contain a surfactant. Further, the organic developer may contain a small amount of water.
At the time of development, the development may be stopped by substituting with a solvent of a type different from that of 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 cleaning, it is preferable to remove the rinse liquid remaining on the substrate and the pattern.

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

The present invention will be described in more detail with reference to examples. In the examples, "%" and "part" representing the content or the 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)
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)

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

式（ａａ−１−ａ）で表される化合物８．００部、式（ａａ−１−ｂ）で表される化合物１０．５６部、クロロホルム４０部及び硫酸０．５２２部を添加し、モレキュラーシーブ２０ｍｌ存在下、２時間還流攪拌した。得られた反応物を２３℃まで冷却し、クロロホルム１２５部を添加撹拌後、さらに、１０％炭酸カリウム水溶液３６．８部を加え、２３℃で３０分間攪拌した。その後、静置し、分液した。回収された有機層に、イオン交換水５０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３回行った。得られた有機層を濃縮することにより、式（ａａ−１−ｃ）で表される化合物１２．５８部を得た。 Example 1: Synthesis of salt represented by the formula (aa-1)

8.00 parts of the compound represented by the formula (aa-1-a), 10.56 parts of the compound represented by the formula (aa-1-b), 40 parts of chloroform and 0.522 parts of sulfuric acid were added, and the mixture was added. The mixture was refluxed and stirred for 2 hours in the presence of 20 ml of sheave. The obtained reaction product was cooled to 23 ° C., 125 parts of chloroform was added and stirred, then 36.8 parts of a 10% potassium carbonate aqueous solution was added, and the mixture was stirred at 23 ° C. for 30 minutes. Then, it was allowed to stand and the liquid was separated. 50 parts of ion-exchanged water was added to the recovered organic layer, and the mixture was stirred at 23 ° C. for 30 minutes and separated to recover the organic layer. This washing operation was performed three times. By concentrating the obtained organic layer, 12.58 parts of the compound represented by the formula (aa-1-c) was obtained.

式（ａａ−１−ｄ）で表される塩６．００部及びアセトニトリル３０部を添加し、２３℃で３０分間攪拌した。得られた混合溶液に、式（ａａ−１−ｅ）で表される化合物３．３３部を添加し、さらに、７０℃で２時間攪拌することにより、式（ａａ−１−ｆ）で表される塩を含む溶液を得た。

6.00 parts of the salt represented by the formula (aa-1-d) and 30 parts of acetonitrile were added, and the mixture was stirred at 23 ° C. for 30 minutes. To the obtained mixed solution, 3.33 parts of the compound represented by the formula (aa-1-e) was added, and the mixture was further stirred at 70 ° C. for 2 hours to be represented by the formula (aa-1-f). A solution containing the salt to be grown was obtained.

得られた式（ａａ−１−ｆ）で表される塩を含む溶液に、式（ａａ−１−ｃ）で表される化合物５．４３部を添加し、さらに、８０℃で３時間攪拌し、濃縮した。得られた濃縮物に、クロロホルム１４５部及びイオン交換水７２部を加えて２３℃で３０分間攪拌し、分液して有機層を取り出した。得られた有機層にイオン交換水７２部を加えて２３℃で３０分間攪拌し、分液して有機層を取り出した。この操作を５回繰り返した。得られた有機層を濃縮し、得られた残渣に、アセトニトリル１２．９８部及びｔｅｒｔ−ブチルメチルエーテル１２９．８０部を加えて攪拌し、上澄液を除去した。得られた残渣を濃縮することにより、式（ａａ−１）で表される塩６．１４部を得た。

To the obtained solution containing the salt represented by the formula (aa-1-f), 5.43 parts of the compound represented by the formula (aa-1-c) was added, and the mixture was further stirred at 80 ° C. for 3 hours. And concentrated. To the obtained concentrate, 145 parts of chloroform and 72 parts of ion-exchanged water were added, and the mixture was stirred at 23 ° C. for 30 minutes, separated into liquids, and the organic layer was taken out. 72 parts of ion-exchanged water was added to the obtained organic layer, and the mixture was stirred at 23 ° C. for 30 minutes, separated into liquids, and the organic layer was taken out. This operation was repeated 5 times. The obtained organic layer was concentrated, 12.98 parts of acetonitrile and 129.80 parts of tert-butyl methyl ether were added to the obtained residue, and the mixture was stirred to remove the supernatant. By concentrating the obtained residue, 6.14 parts of a salt represented by the formula (aa-1) was obtained.

MASS (ESI (+) Spectrum): M ⁺ 263.1
MASS (ESI (-) Spectrum): M ^- 421.1

式（ａａ−２−ａ）で表される化合物８．００部、式（ａａ−２−ｂ）で表される化合物９．５４部、クロロホルム４０部及び硫酸０．４７２部を添加し、モレキュラーシーブ２０ｍｌ存在下、２時間還流攪拌した。得られた反応物を２３℃まで冷却し、クロロホルム１２５部を添加撹拌後、さらに、１０％炭酸カリウム水溶液３３．３部を加え、２３℃で３０分間攪拌した。その後、静置し、分液した。回収された有機層に、イオン交換水５０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３回行った。得られた有機層を濃縮することにより、式（ａａ−２−ｃ）で表される化合物１２．５３部を得た。 Example 2: Synthesis of salt represented by the formula (aa-2)

8.00 parts of the compound represented by the formula (aa-2-a), 9.54 parts of the compound represented by the formula (aa-2-b), 40 parts of chloroform and 0.472 parts of sulfuric acid were added, and the mixture was added. The mixture was refluxed and stirred for 2 hours in the presence of 20 ml of sheave. The obtained reaction product was cooled to 23 ° C., 125 parts of chloroform was added and stirred, then 33.3 parts of a 10% potassium carbonate aqueous solution was added, and the mixture was stirred at 23 ° C. for 30 minutes. Then, it was allowed to stand and the liquid was separated. 50 parts of ion-exchanged water was added to the recovered organic layer, and the mixture was stirred at 23 ° C. for 30 minutes and separated to recover the organic layer. This washing operation was performed three times. By concentrating the obtained organic layer, 12.53 parts of the compound represented by the formula (aa-2-c) was obtained.

式（ａａ−２−ｄ）で表される塩６．００部及びアセトニトリル３０部を添加し、２３℃で３０分間攪拌した。得られた混合溶液に、式（ａａ−２−ｅ）で表される化合物３．３３部を添加し、さらに、７０℃で２時間攪拌することにより、式（ａａ−２−ｆ）で表される塩を含む溶液を得た。

6.00 parts of the salt represented by the formula (aa-2-d) and 30 parts of acetonitrile were added, and the mixture was stirred at 23 ° C. for 30 minutes. To the obtained mixed solution, 3.33 parts of the compound represented by the formula (aa-2-e) was added, and the mixture was further stirred at 70 ° C. for 2 hours to be represented by the formula (aa-2-f). A solution containing the salt to be added was obtained.

得られた式（ａａ−２−ｆ）で表される塩を含む溶液に、式（ａａ−２−ｃ）で表される化合物５．７５部を添加し、さらに、８０℃で３時間攪拌し、濃縮した。得られた濃縮物に、クロロホルム１４５部及びイオン交換水７５部を加えて２３℃で３０分間攪拌し、分液して有機層を取り出した。得られた有機層にイオン交換水７５部を加えて２３℃で３０分間攪拌し、分液して有機層を取り出した。この操作を５回繰り返した。得られた有機層を濃縮し、得られた残渣に、アセトニトリル１３．４５部及びｔｅｒｔ−ブチルメチルエーテル１３４．５０部を加えて攪拌し、上澄液を除去した。得られた残渣を濃縮することにより、式（ａａ−２）で表される塩７．７２部を得た。

5.75 parts of the compound represented by the formula (aa-2-c) is added to the obtained solution containing the salt represented by the formula (aa-2-f), and the mixture is further stirred at 80 ° C. for 3 hours. And concentrated. To the obtained concentrate, 145 parts of chloroform and 75 parts of ion-exchanged water were added, and the mixture was stirred at 23 ° C. for 30 minutes and separated to remove the organic layer. 75 parts of ion-exchanged water was added to the obtained organic layer, and the mixture was stirred at 23 ° C. for 30 minutes, separated into liquids, and the organic layer was taken out. This operation was repeated 5 times. The obtained organic layer was concentrated, 13.45 parts of acetonitrile and 134.50 parts of tert-butyl methyl ether were added to the obtained residue, and the mixture was stirred to remove the supernatant. By concentrating the obtained residue, 7.72 parts of a salt represented by the formula (aa-2) was obtained.

MASS (ESI (+) Spectrum): M ⁺ 263.1
MASS (ESI (-) Spectrum): M ^- 437.1

式（ａａ−６２−ａ）で表される塩９．３９部及びアセトニトリル５０部を添加し、２３℃で３０分間攪拌した。得られた混合溶液に、式（ａａ−６２−ｂ）で表される化合物４．０４部を添加し、さらに、７０℃で２時間攪拌することにより、式（ａａ−６２−ｃ）で表される塩を含む溶液を得た。 Example 3: Synthesis of salt represented by formula (aa-62)

9.39 parts of salt and 50 parts of acetonitrile represented by the formula (aa-62-a) were added, and the mixture was stirred at 23 ° C. for 30 minutes. To the obtained mixed solution, 4.04 parts of the compound represented by the formula (aa-62-b) was added, and the mixture was further stirred at 70 ° C. for 2 hours to be represented by the formula (aa-62-c). A solution containing the salt to be added was obtained.

得られた式（ａａ−６２−ｃ）で表される塩を含む溶液に、式（ａａ−２−ｃ）で表される化合物５．７５部を添加し、さらに、２３℃で１８時間攪拌し、濃縮した。得られた濃縮物に、クロロホルム１００部及びイオン交換水３５部を加えて２３℃で３０分間攪拌し、分液して有機層を取り出した。得られた有機層にイオン交換水３５部を加えて２３℃で３０分間攪拌し、分液して有機層を取り出した。この操作を５回繰り返した。得られた有機層を濃縮し、得られた残渣に、ｔｅｒｔ−ブチルメチルエーテル３０部を加えて攪拌し、上澄液を除去した。得られた残渣を濃縮することにより、式（ａａ−６２）で表される塩９．１１部を得た。

To the obtained solution containing the salt represented by the formula (aa-62-c), 5.75 parts of the compound represented by the formula (aa-2-c) was added, and the mixture was further stirred at 23 ° C. for 18 hours. And concentrated. To the obtained concentrate, 100 parts of chloroform and 35 parts of ion-exchanged water were added, and the mixture was stirred at 23 ° C. for 30 minutes and separated to remove the organic layer. 35 parts of ion-exchanged water was added to the obtained organic layer, and the mixture was stirred at 23 ° C. for 30 minutes, separated into liquids, and the organic layer was taken out. This operation was repeated 5 times. The obtained organic layer was concentrated, 30 parts of tert-butyl methyl ether was added to the obtained residue, and the mixture was stirred to remove the supernatant. By concentrating the obtained residue, 9/11 parts of a salt represented by the formula (aa-62) was obtained.

MASS (ESI (+) Spectrum): M ⁺ 237.1
MASS (ESI (-) Spectrum): M ^- 437.1

式（ａａ−６２）で表される塩５．４４部及びクロロホルム３０部を混合し、２３℃で３０分間攪拌した後、５℃まで冷却した。得られた混合物に、式（ａａ−１５５−ａ）で表される化合物０．８７部及びｐ−トルエンスルホン酸０．２部を仕込み、１０℃で２時間攪拌した。得られた混合物にイオン交換水３０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３０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。回収された有機層を濃縮し、濃縮マスをカラム（関東化学 シリカゲル６０Ｎ（球状、中性）１００−２１０μｍ 展開溶媒：クロロホルム／メタノール＝１／１）分取することにより、式（ａａ−１５５）で表される塩１．０４部を得た。
ＭＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ２３７．１
ＭＳ（ＥＳＩ（−）Ｓｐｅｃｔｒｕｍ）：Ｍ⁻ ５０９．２ Example 4: Synthesis of salt represented by the formula (aa-155)

5.44 parts of the salt represented by the formula (aa-62) and 30 parts of chloroform were mixed, stirred at 23 ° C. for 30 minutes, and then cooled to 5 ° C. To the obtained mixture was charged 0.87 part of the compound represented by the formula (aa-155-a) and 0.2 part of p-toluenesulfonic acid, and the mixture was stirred at 10 ° C. for 2 hours. 30 parts of ion-exchanged water was added to the obtained mixture, and the mixture was stirred at 23 ° C. for 30 minutes and separated to recover the organic layer. 30 parts of ion-exchanged water was charged into the recovered organic layer, stirred at 23 ° C. for 30 minutes, and separated to recover the organic layer. This washing operation was performed 5 times. The recovered organic layer is concentrated, and the concentrated mass is separated by a column (Kanto Chemical silica gel 60N (spherical, neutral) 100-210 μm developing solvent: chloroform / methanol = 1/1) to formula (aa-155). 1.04 parts of salt represented by is obtained.
MS (ESI (+) Electrospray ^{): M + 237.1}
MS (ESI (-) Electrospray): M ^- 509.2

式（ａａ−６２）で表される塩４．５３部、クロロホルム２５部及びピリジン１．５９部を混合し、２３℃で３０分間攪拌した後、５℃まで冷却した。得られた混合物に、式（ａａ−１５７−ａ）で表される化合物１．０３部を１時間かけて滴下し、さらに２３℃で３時間攪拌した後、濃縮した。得られた濃縮残にクロロホルム６０部及びイオン交換水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。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、濃縮残に酢酸エチル３０部を加えて攪拌した後、上澄液を除去した。得られた有機層を濃縮した後、濃縮残に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（ａａ−１５７）で表される塩２．８１部を得た。
ＭＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ２３７．１
ＭＳ（ＥＳＩ（−）Ｓｐｅｃｔｒｕｍ）：Ｍ⁻ ４７９．１ Example 5: Synthesis of salt represented by the formula (aa-157)

4.53 parts of salt represented by the formula (aa-62), 25 parts of chloroform and 1.59 parts of pyridine were mixed, stirred at 23 ° C. for 30 minutes, and then cooled to 5 ° C. To the obtained mixture, 1.03 part of the compound represented by the formula (aa-157-a) was added dropwise over 1 hour, and the mixture was further stirred at 23 ° C. for 3 hours and then concentrated. 60 parts of chloroform and 20 parts of ion-exchanged water were added to the obtained concentrated residue, and the mixture was stirred at 23 ° C. for 30 minutes and separated to recover the organic layer. Twenty parts of ion-exchanged water was charged into the recovered organic layer, 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, 30 parts of ethyl acetate was added to the concentrated residue and stirred, and then the supernatant was removed. After concentrating the obtained organic layer, 30 parts of tert-butyl methyl ether was added to the concentrated residue and stirred, and then the supernatant was removed. The obtained residue was dissolved in acetonitrile and concentrated to obtain 2.81 parts of a salt represented by the formula (aa-157).
MS (ESI (+) Electrospray ^{): M + 237.1}
MS (ESI (-) Electrospray ^{): M-479.1}

式（ａａ−６８−ａ）で表される塩９．０７部及びアセトニトリル５０部を添加し、２３℃で３０分間攪拌した。得られた混合溶液に、式（ａａ−６８−ｂ）で表される化合物４．０４部を添加し、さらに、７０℃で２時間攪拌することにより、式（ａａ−６８−ｃ）で表される塩を含む溶液を得た。 Example 6: Synthesis of salt represented by formula (aa-68)

9.07 parts of salt represented by the formula (aa-68-a) and 50 parts of acetonitrile were added, and the mixture was stirred at 23 ° C. for 30 minutes. To the obtained mixed solution, 4.04 parts of the compound represented by the formula (aa-68-b) was added, and the mixture was further stirred at 70 ° C. for 2 hours to be represented by the formula (aa-68-c). A solution containing the salt to be added was obtained.

得られた式（ａａ−６８−ｃ）で表される塩を含む溶液に、式（ａａ−２−ｃ）で表される化合物５．７５部を添加し、さらに、２３℃で１８時間攪拌し、濃縮した。得られた濃縮物に、クロロホルム１００部及びイオン交換水３５部を加えて２３℃で３０分間攪拌し、分液して有機層を取り出した。得られた有機層にイオン交換水３５部を加えて２３℃で３０分間攪拌し、分液して有機層を取り出した。この操作を５回繰り返した。得られた有機層を濃縮し、得られた残渣に、ｔｅｒｔ−ブチルメチルエーテル３０部を加えて攪拌し、上澄液を除去した。得られた残渣を濃縮することにより、式（ａａ−６８）で表される塩８．４８部を得た。

To the obtained solution containing the salt represented by the formula (aa-68-c), 5.75 parts of the compound represented by the formula (aa-2-c) was added, and the mixture was further stirred at 23 ° C. for 18 hours. And concentrated. To the obtained concentrate, 100 parts of chloroform and 35 parts of ion-exchanged water were added, and the mixture was stirred at 23 ° C. for 30 minutes and separated to remove the organic layer. 35 parts of ion-exchanged water was added to the obtained organic layer, and the mixture was stirred at 23 ° C. for 30 minutes, separated into liquids, and the organic layer was taken out. This operation was repeated 5 times. The obtained organic layer was concentrated, 30 parts of tert-butyl methyl ether was added to the obtained residue, and the mixture was stirred to remove the supernatant. By concentrating the obtained residue, 8.48 parts of a salt represented by the formula (aa-68) was obtained.

MASS (ESI (+) Spectrum): M ⁺ 237.1
MASS (ESI (-) Spectrum): M ^- 467.1

式（ａａ−６８）で表される塩５．５８部及びクロロホルム３０部を混合し、２３℃で３０分間攪拌した後、５℃まで冷却した。得られた混合物に、式（ａａ−１５５−ａ）で表される化合物０．８７部及びｐ−トルエンスルホン酸０．２部を仕込み、１０℃で２時間攪拌した。得られた混合物にイオン交換水３０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３０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。回収された有機層を濃縮し、濃縮マスをカラム（関東化学 シリカゲル６０Ｎ（球状、中性）１００−２１０μｍ 展開溶媒：クロロホルム／メタノール＝１／１）分取することにより、式（ａａ−１６３）で表される塩１．０４部を得た。
ＭＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ２３７．１
ＭＳ（ＥＳＩ（−）Ｓｐｅｃｔｒｕｍ）：Ｍ⁻ ５３９．２ Example 7: Synthesis of salt represented by the formula (aa-163)

5.58 parts of the salt represented by the formula (aa-68) and 30 parts of chloroform were mixed, stirred at 23 ° C. for 30 minutes, and then cooled to 5 ° C. To the obtained mixture was charged 0.87 part of the compound represented by the formula (aa-155-a) and 0.2 part of p-toluenesulfonic acid, and the mixture was stirred at 10 ° C. for 2 hours. 30 parts of ion-exchanged water was added to the obtained mixture, and the mixture was stirred at 23 ° C. for 30 minutes and separated to recover the organic layer. 30 parts of ion-exchanged water was charged into the recovered organic layer, stirred at 23 ° C. for 30 minutes, and separated to recover the organic layer. This washing operation was performed 5 times. The recovered organic layer is concentrated, and the concentrated mass is separated into a column (Kanto Chemical silica gel 60N (spherical, neutral) 100-210 μm developing solvent: chloroform / methanol = 1/1) to formula (aa-163). 1.04 parts of salt represented by is obtained.
MS (ESI (+) Electrospray ^{): M + 237.1}
MS (ESI (-) Spectrum): M ^- 539.2

式（ａａ−６８）で表される塩４．７３部、クロロホルム２５部及びピリジン１．５９部を混合し、２３℃で３０分間攪拌した後、５℃まで冷却した。得られた混合物に、式（ａａ−１５７−ａ）で表される化合物１．０３部を１時間かけて滴下し、さらに２３℃で３時間攪拌した後、濃縮した。得られた濃縮残にクロロホルム６０部及びイオン交換水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。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、濃縮残に酢酸エチル３０部を加えて攪拌した後、上澄液を除去した。得られた有機層を濃縮した後、濃縮残に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（ａａ−１６１）で表される塩２．２６部を得た。
ＭＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ２３７．１
ＭＳ（ＥＳＩ（−）Ｓｐｅｃｔｒｕｍ）：Ｍ⁻ ５０９．１ Example 8: Synthesis of salt represented by the formula (aa-161)

4.73 parts of the salt represented by the formula (aa-68), 25 parts of chloroform and 1.59 parts of pyridine were mixed, stirred at 23 ° C. for 30 minutes, and then cooled to 5 ° C. To the obtained mixture, 1.03 part of the compound represented by the formula (aa-157-a) was added dropwise over 1 hour, and the mixture was further stirred at 23 ° C. for 3 hours and then concentrated. 60 parts of chloroform and 20 parts of ion-exchanged water were added to the obtained concentrated residue, and the mixture was stirred at 23 ° C. for 30 minutes and separated to recover the organic layer. Twenty parts of ion-exchanged water was charged into the recovered organic layer, 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, 30 parts of ethyl acetate was added to the concentrated residue and stirred, and then the supernatant was removed. After concentrating the obtained organic layer, 30 parts of tert-butyl methyl ether was added to the concentrated residue and stirred, and then the supernatant was removed. The obtained residue was dissolved in acetonitrile and concentrated to obtain 2.26 parts of a salt represented by the formula (aa-161).
MS (ESI (+) Electrospray ^{): M + 237.1}
MS (ESI (-) Electrospray ^{): M-509.1}

Synthesis of Resin The compounds (monomers) used for the synthesis of the resin (A) are shown below. Hereinafter, these compounds are referred to as "monomers (a1-1-3)" and the like according to their formula numbers.

Synthesis Example 1: Synthesis of resin A1 As a monomer, a monomer (a1-1-3), a monomer (a1-2-9), a monomer (a2-1-3), and a monomer (a3-4-2) are 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 mixture was mixed so as to have a concentration of 5, and propylene glycol monomethyl ether acetate 1.5% by mass of the total amount of the monomers was added to prepare a solution. To this solution, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added in an amount of 1 mol% and 3 mol%, respectively, based on the total amount of monomers, and these were heated at 73 ° C. for about 5 hours. bottom. The obtained reaction mixture was poured into a large amount of methanol / water mixed solvent to precipitate a resin, and the resin was filtered. The obtained resin is dissolved again in propylene glycol monomethyl ether acetate, and the obtained solution is poured into a methanol / water mixed solvent to precipitate the resin, and the reprecipitation operation of filtering the resin is performed twice, and the weight average is obtained. the resin A1 having a molecular weight of 7.6 × 10 ³ was obtained in 68% yield. This resin A1 has the following structural units.

Synthesis Example 2: Synthesis of resin X1 Monomer (a5-1-1) and monomer (a4-0-12) are used as monomers, and their molar ratio [monomer (a5-1-1): monomer (a4-0-). 12)] was mixed so that the ratio was 50:50, and 1.2% by mass of methyl isobutyl ketone was added to prepare a solution. Azobis (2,4-dimethylvaleronitrile) as an initiator was added to this solution in an amount of 3 mol% based on the total amount of monomers, and the mixture was heated at 70 ° C. for about 5 hours. The reaction mixture obtained, the resin was precipitated by pouring into a large amount of methanol / water mixed solvent, the resin was filtered, to obtain a resin X having a weight-average molecular weight 1.0 × 10 ⁴ in 91% yield. This resin X1 has the following structural units.

<Preparation of resist composition>
As shown in Table 7, each of the following components was mixed, and the obtained mixture was filtered through a fluororesin filter having a pore size of 0.2 μm to prepare a resist composition.

<Resin>
A1, X1: Resin A1, Resin X1
<Salt (aa)>
aa-1: Salt represented by the formula (aa-1) aa-2: Salt represented by the formula (aa-2) aa-62: Salt represented by the formula (aa-62) aa-68: Formula Salt represented by (aa-68) aa-155: Salt represented by formula (aa-155) aa-157: Salt represented by formula (aa-157) aa-161: Formula (aa-161) Salt represented by aa-163: Salt represented by the formula (aa-163) <acid generator (B)>
B1-21: Salt represented by the formula (B1-21) (synthesized according to an example of JP2012-224611)
B1-22: Salt represented by the formula (B1-22) (synthesized according to an example of JP2012-224611)
IX-1: Synthesized according to the examples of JP2011-37837. IX-2: Synthesized according to the examples of JP2012-193160. IX-3: Synthesized according to the examples of JP2012-193160. Synthetic

<Compound (D)>
D1: (manufactured by 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

<Manufacturing of resist pattern and its evaluation>
An organic antireflection film composition (ARC-29; manufactured by Nissan Chemical Industries, Ltd.) is applied to a silicon wafer and baked at 205 ° C. for 60 seconds to produce organic reflection on the wafer with a film thickness of 78 nm. An anti-reflective film was formed. Next, the above resist composition was applied (spin coated) on the organic antireflection film so that the film thickness after drying was 85 nm. After coating, the silicon wafer was prebaked on a direct hot plate at the temperature listed in the “PB” column of Table 7 for 60 seconds to form a composition layer. A contact hole pattern (hole pitch 90 nm) was used on a silicon wafer on which a composition layer was formed with an ArF excimer stepper for immersion exposure (XT: 1900 Gi; manufactured by ASML, NA = 1.35, 3/4 Anal XY polarization). / Using a mask for forming a hole diameter of 55 nm), the exposure amount was changed stepwise for exposure. Ultrapure water was used as the immersion medium.
After the exposure, post-exposure baking was performed on a hot plate at the temperature listed in the “PEB” column of Table 7 for 60 seconds. Next, the composition layer on the silicon wafer was developed by the dynamic dispensing method at 23 ° C. for 20 seconds using butyl acetate (manufactured by Tokyo Chemical Industry Co., Ltd.) as a developing solution to form a negative resist pattern. Manufactured.

In the resist pattern obtained after development, the exposure amount at which the hole diameter formed by using the mask was 45 nm was defined as the effective sensitivity.

<Mask error factor (MEF) evaluation>
In terms of effective sensitivity, a resist pattern was formed using masks having mask hole diameters (hole diameters of translucent portions of the mask) of 57 nm, 56 nm, 55 nm, 54 nm, and 53 nm (hole pitches are all 90 nm), respectively. The slope of the regression line when the hole diameter of the resist pattern formed (transferred) on the substrate by exposure was plotted on the vertical axis with the mask hole diameter on the horizontal axis was calculated as the MEF value.
Those with a MEF value of 5.0 or less are evaluated as having a good MEF, and are marked with ○.
Those having a MEF value of more than 5.0 were evaluated as having poor MEF and were evaluated as x.
The results are shown in Table 8. The numbers in parentheses indicate the MEF value.

The resist composition containing the salt of the present invention is suitable for microfabrication of semiconductors because a resist pattern can be produced with a good mask error factor (MEF).

Claims (8)

A salt having an anion represented by the formula (aa2).

[In equation (aa2),
X ^a and X ^b independently represent an oxygen atom or a sulfur atom, and X ^a and X ^b are bonded to two consecutive carbon atoms in ring W ^1.
Ring W ¹ and ring W ² independently represent a ring represented by any of the formulas (w1-1) to (w1-11), and the hydrogen atom contained in the ring is a hydroxy group or a carbon. 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, an acyl group having 2 to 13 carbon atoms, an acyloxy group having 2 to 13 carbon atoms, and 3 to 12 carbon atoms. It may be substituted with an alicyclic hydrocarbon group of 6 to 10 or an aromatic hydrocarbon group having 6 to 10 carbon atoms.

L ^b1 represents a group represented by any of the formulas (b1-2) and formulas (b1-5) to (b1-11).
Q ¹ and Q ² independently represent a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms. ]

[In equation (b1-2),
L ^b4 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms.
L ^b5 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms.
However, the total number of carbon atoms of ^{L b4} and L ^{b5 is 22 or less.}
* Represents a bond with ring W ^1. ]

[In equation (b1-5),
L ^b9 represents a divalent saturated hydrocarbon group having 1 to 20 carbon atoms.
L ^b10 represents a single bond or a divalent saturated hydrocarbon group having 1 to 19 carbon atoms.
However, the total number of carbon atoms of ^{L b9} and L ^{b10 is 20 or less.}
In equation (b1-6),
L ^b11 represents a divalent saturated hydrocarbon group having 1 to 21 carbon atoms.
L ^b12 represents a single bond or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms.
However, the total number of carbon atoms of ^{L b11} and L ^{b12 is 21 or less.}
In equation (b1-7),
L ^b13 represents a divalent saturated hydrocarbon group having 1 to 19 carbon atoms.
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 divalent saturated hydrocarbon group having 1 to 18 carbon atoms.
However, the total number of carbon atoms of ^{L b13} , L ^b14 and L ^{b15 is 19 or less.}
In equation (b1-8),
L ^b16 represents a divalent saturated hydrocarbon group having 1 to 18 carbon atoms.
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.
However, the total carbon number of ^{L b16} , L ^b17 and L ^{b18 is 19 or less.}
* Represents a bond with ring W ^1. ]

[In equation (b1-9),
L ^b19 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms.
L ^b20 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms.
However, the total number of carbon atoms of ^{L b19} and L ^{b20 is 23 or less.}
In equation (b1-10),
L ^b21 represents a single bond or a divalent saturated hydrocarbon group having 1 to 21 carbon atoms.
L ^b22 represents a single bond or a divalent saturated hydrocarbon group having 1 to 21 carbon atoms.
L ^b23 represents a single bond or a divalent saturated hydrocarbon group having 1 to 21 carbon atoms.
However, the total carbon number of ^{L b21} , L ^b22 and L ^{b23 is 21 or less.}
In equation (b1-11),
L ^b24 represents a single bond or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms.
L ^b25 represents a divalent saturated hydrocarbon group having 1 to 21 carbon atoms.
L ^b26 represents a single bond or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms.
However, L ^b24, the total number of carbon atoms of L ^b25 and L ^b26 is 21 or less.
* Represents a bond with ring W ^1. ] Rings W ¹ and W ² are independently represented by a ring represented by the formula (w1-1), a ring represented by the formula (w1-2), a ring represented by the formula (w1-3), or a formula. The salt according to claim 1, which is a ring represented by (w1-6).

[In the formula (w1-1), the formula (w1-2), the formula (w1-3) and the formula (w1-6),
The hydrogen atom contained in the ring 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, an acyl group having 2 to 13 carbon atoms, and a carbon number of carbon atoms. It may be substituted with an acyloxy group of 2 to 13, an alicyclic hydrocarbon group having 3 to 12 carbon atoms, or an aromatic hydrocarbon group having 6 to 10 carbon atoms. ] L ^b1 is a group represented by the formula (b1-2), L ^b4 is a divalent saturated hydrocarbon group ^{having 1 to 8 carbon atoms, and L b5} is a single bond or 1 to 8 carbon atoms. The salt according to claim 1 or 2, which is a divalent saturated hydrocarbon group of the above. L ^b1 is a group represented by any of the formulas (b1-5) to (b1-8), L ^b9 is a divalent saturated hydrocarbon group having 1 to 8 carbon atoms, and L ^b10. Is a single bond or a divalent saturated hydrocarbon group ^{having 1 to 8 carbon atoms, L b11} is a divalent saturated hydrocarbon group having 1 to 8 carbon atoms, and L ^b12 is a single bond or a divalent saturated hydrocarbon group having 1 to 8 carbon atoms. It is a divalent saturated hydrocarbon group of 1 to 8, L ^b13 is a divalent saturated hydrocarbon group having 1 to 12 carbon atoms, and L ^b14 is a single bond or a divalent saturated hydrocarbon group having 1 to 6 carbon atoms. It is a saturated hydrocarbon group, L ^b15 is a single bond or a divalent saturated hydrocarbon group having 1 to 8 carbon atoms, and L ^b16 is a divalent saturated hydrocarbon group having 1 to 12 carbon atoms. L ^b17 is a divalent saturated hydrocarbon group having 1 to 6 carbon atoms, L ^b18 is as claimed in claim 1 or 2 is a single bond or a divalent saturated hydrocarbon group having 1 to 4 carbon atoms salt. An acid generator containing the salt according to any one of claims 1 to 4. A resist composition containing the acid generator according to claim 5 and a resin having an acid unstable group. The resist composition according to claim 6, further comprising a salt that generates an acid having a weaker acidity than the acid generated from the acid generator. (1) A step of applying the resist composition according to claim 6 or 7 onto a substrate.
(2) A step of drying the applied composition to form a composition layer,
(3) 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.