JP2012121879A - Salt, resist composition and method for producing resist pattern - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an acid generator capable of producing a resist pattern having excellent line edge roughness (LER), and to provide a resist composition containing the same.SOLUTION: The salt is represented by formula (I), wherein Rand Reach independently represent fluorine atom or a 1-6C perfluoroalkyl. Lrepresents a single bond or divalent 1-17C saturated hydrocarbon group or the like. Y represents a 1-18C aliphatic hydrocarbon group, a 3-18C alicyclic hydrocarbon group which may have a substituent, or the like. Zrepresents an organic cation having a pyridine ring.

Description

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

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

JP 2007-161707 A

  In the conventional resist compositions containing the above-mentioned acid generator, the line pattern roughness (LER) of the resulting resist pattern may not always be sufficiently satisfied.

［式（Ｉ）中、
Ｒ^１及びＲ^２は、それぞれ独立に、フッ素原子又は炭素数１〜６のペルフルオロアルキル基を表す。
Ｌ^１は、単結合又は２価の炭素数１〜１７の飽和炭化水素基を表し、該２価の飽和炭化水素基に含まれる水素原子はフッ素原子で置換されていてもよく、該２価の飽和炭化水素基を構成しているメチレン基は、酸素原子又はカルボニル基で置き換わっていてもよい。
Ｙは、炭素数１〜１８の脂肪族炭化水素基又は置換基を有していてもよい炭素数３〜１８の脂環式炭化水素基を表し、該脂肪族炭化水素基及び該脂環式炭化水素基を構成しているメチレン基は、酸素原子、スルホニル基又はカルボニル基で置き換わっていてもよい。
Ｚ^１+は、ピリジン環を有する有機カチオンを表す。］
〔２〕前記Ｚ^１+が、式（Ｉ−Ｚ^１−１）で表される有機カチオンである前記〔１〕記載の塩。

［式（Ｉ−Ｚ^１−１）中、
Ｒ^３及びＲ^４は、それぞれ独立に、水素原子、ハロゲン原子、ヒドロキシ基、シアノ基、炭素数１〜１０のアルキル基、炭素数１〜４のアルコキシ基又は炭素数２〜５のアシル基を表す。］
〔３〕前記Ｚ^１+が、式（Ｉ−Ｚ^１−１−１）で表される有機カチオンである前記〔１〕記載の塩。

〔４〕前記Ｌ¹が、＊−ＣＯ−Ｏ−（ＣＨ_２）_ｎ−（＊は、−Ｃ（Ｒ^１）（Ｒ^２）−との結合手を表し、ｎは０又は１を表す。）で表される基である前記〔１〕〜前記〔３〕のいずれか記載の塩。
〔５〕前記〔１〕〜前記〔４〕のいずれか記載の塩を含有する酸発生剤。
〔６〕前記〔５〕記載の酸発生剤と樹脂とを含み、該樹脂は酸に不安定な基を有し、かつアルカリ水溶液に不溶又は難溶な樹脂であり、酸との作用によりアルカリ水溶液で溶解し得る樹脂であるレジスト組成物。
〔７〕（１）前記〔６〕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）組成物層に露光機を用いて露光する工程、
（４）露光後の組成物層を加熱する工程、
（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 represented by the formula (I).

[In the formula (I),
R ¹ and R ² each independently represents a fluorine atom or a C 1-6 perfluoroalkyl group.
L ¹ represents a single bond or a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, a hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with a fluorine atom, and the divalent The methylene group constituting the saturated hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
Y represents an aliphatic hydrocarbon group having 1 to 18 carbon atoms or an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent, and the aliphatic hydrocarbon group and the alicyclic group. The methylene group constituting the hydrocarbon group may be replaced with an oxygen atom, a sulfonyl group or a carbonyl group.
Z ¹⁺ represents an organic cation having a pyridine ring. ]
[2] The salt according to [1], wherein Z ¹⁺ is an organic cation represented by the formula (I-Z ¹ -1).

[In the formula (I-Z ¹ -1),
R ³ and R ⁴ each independently represent a hydrogen atom, a halogen atom, a hydroxy group, a cyano group, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or an acyl group having 2 to 5 carbon atoms. To express. ]
[3] The salt according to [1], wherein Z ¹⁺ is an organic cation represented by the formula (I-Z ¹ -1-1).

[4] L ¹ represents * —CO—O— (CH ₂ ) _n — (* represents a bond with —C (R ¹ ) (R ² ) —, and n represents 0 or 1. The salt according to any one of [1] to [3] above, which is a group represented by:
[5] An acid generator containing the salt according to any one of [1] to [4].
[6] The acid generator according to [5] and a resin, wherein the resin has an acid labile group and is insoluble or hardly soluble in an aqueous alkali solution. A resist composition, which is a resin that can be dissolved in an aqueous solution.
[7] (1) A step of applying the resist composition according to [6] on a substrate,
(2) The process of drying the composition after application | coating and forming a composition layer,
(3) a step of exposing the composition layer using an exposure machine;
(4) A step of heating the composition layer after exposure,
(5) a step of developing the composition layer after heating;
A method for producing a resist pattern including:

  If the resist composition containing the salt of the present invention is used as an acid generator, a resist pattern having excellent line edge roughness (LER) can be produced.

［式（Ｉ）中、
Ｒ^１及びＲ^２は、それぞれ独立に、フッ素原子又は炭素数１〜６のペルフルオロアルキル基を表す。
Ｌ^１は、単結合又は２価の炭素数１〜１７の飽和炭化水素基を表し、該２価の飽和炭化水素基に含まれる水素原子はフッ素原子で置換されていてもよく、該２価の飽和炭化水素基を構成しているメチレン基は、酸素原子又はカルボニル基で置き換わっていてもよい。
Ｙは、炭素数１〜１８の脂肪族炭化水素基又は置換基を有していてもよい炭素数３〜１８の脂環式炭化水素基を表し、該脂肪族炭化水素基及び該脂環式炭化水素基を構成しているメチレン基は、酸素原子、スルホニル基又はカルボニル基で置き換わっていてもよい。
Ｚ^１+は、ピリジン環を有する有機カチオンを表す。］
なお、以下の説明において、塩（Ｉ）のうち、正電荷を有するＺ^１+で示される有機カチオンを除去してなる負電荷を有するものを「スルホン酸アニオン」ということがある。 <Salt>
The salt of the present invention is a salt represented by the formula (I) (hereinafter sometimes referred to as “salt (I)”).

[In the formula (I),
R ¹ and R ² each independently represents a fluorine atom or a C 1-6 perfluoroalkyl group.
L ¹ represents a single bond or a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, a hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with a fluorine atom, and the divalent The methylene group constituting the saturated hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
Y represents an aliphatic hydrocarbon group having 1 to 18 carbon atoms or an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent, and the aliphatic hydrocarbon group and the alicyclic group. The methylene group constituting the hydrocarbon group may be replaced with an oxygen atom, a sulfonyl group or a carbonyl group.
Z ¹⁺ represents an organic cation having a pyridine ring. ]
In the following description, the salt (I) having a negative charge obtained by removing an organic cation represented by Z ¹⁺ having a positive charge may be referred to as a “sulfonate anion”.

Examples of the C 1-6 perfluoroalkyl group represented by R ¹ and R ² include trifluoromethyl group, perfluoroethyl group, perfluoropropyl group, perfluoroisopropyl group, perfluorobutyl group, perfluoro sec-butyl group, Examples thereof include a perfluoro tert-butyl group, a perfluoropentyl group, and a perfluorohexyl group.
As an acid generator used in the resist composition of the present invention, R ¹ and R ² are each independently preferably a trifluoromethyl group or a salt (I) which is a fluorine atom, and both are salts (I) which are both a fluorine atom. Is more preferable.

Examples of the divalent saturated hydrocarbon group having 1 to 17 carbon atoms represented by L ¹ include a linear alkanediyl group, a branched alkanediyl group, a monocyclic or polycyclic divalent alicyclic carbonization. A hydrogen group may be mentioned, and two or more of these groups may be combined. Specific divalent saturated hydrocarbon groups are shown below.
Methylene group, ethylene group, propane-1,3-diyl group, propane-1,2-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group , Heptane-1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group, dodecane-1, 12-diyl group, tridecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, hexadecane-1,16-diyl group, heptadecane-1,17-diyl group, Linear alkanediyl groups such as ethane-1,1-diyl group, propane-1,1-diyl group and propane-2,2-diyl group;
An alkyl group (particularly an alkyl group having 1 to 4 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group); Branched alkylene groups having a side chain of, for example, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1, Branched alkanediyl groups such as 4-diyl group, 2-methylbutane-1,4-diyl group;
Cyclobutane-1,3-diyl group, cyclopentane-1,3-diyl group, cyclohexane-1,2-diyl group, 1-methylcyclohexane-1,2-diyl group, cyclohexane-1,4-diyl group, cyclo A monocyclic divalent alicyclic hydrocarbon group which is a cycloalkanediyl group such as an octane-1,2-diyl group or a cyclooctane-1,5-diyl group;
Norbornane-2,3-diyl group, norbornane-1,4-diyl group, norbornane-2,5-diyl group, adamantane-1,2-diyl group, adamantane-1,5-diyl group and adamantane-2,6 -A polycyclic divalent alicyclic hydrocarbon group such as diyl;

式（ｂ１−１）〜式（ｂ１−６）中、
Ｌ^b2は、単結合又は炭素数１〜１５の２価の飽和炭化水素基を表す。
Ｌ^b3は、単結合又は炭素数１〜１２の２価の飽和炭化水素基を表す。
Ｌ^b4は、炭素数１〜１３の２価の飽和炭化水素基を表す。但しＬ^b3及びＬ^b4の合計炭素数の上限は１３である。
Ｌ^b５は、炭素数１〜１５の２価の飽和炭化水素基を表す。
Ｌ^b6は、単結合又は炭素数１〜１５の２価の飽和炭化水素基を表す。
Ｌ^b7は、炭素数１〜１５の２価の飽和炭化水素基を表す。但しＬ^b6及びＬ^b7の合計炭素数の上限は１６である。
Ｌ^b8は、炭素数１〜１４の２価の飽和炭化水素基を表す。
Ｌ^b9及びＬ^b10は、それぞれ独立に、炭素数１〜１１の２価の飽和炭化水素基を表す。但しＬ^b9及びＬ^b10の合計炭素数の上限は１２である。
本発明のレジスト組成物に用いる酸発生剤としては、これらの中でも、式（ｂ１−１）で表される２価の基をＬ¹として有する塩（Ｉ）が好ましく、Ｌ^b2が単結合又はメチレン基である式（ｂ１−１）で表される２価の基をＬ¹として有する塩（Ｉ）がより好ましい。 Examples of the group in which the methylene group constituting the divalent saturated hydrocarbon group having 1 to 17 carbon atoms represented by L ¹ is replaced by an oxygen atom or a carbonyl group include the following formula (b1-1): To a group represented by any one of formulas (b1-6). L ¹ is preferably a group represented by any one of formulas (b1-1) to (b1-4), more preferably a group represented by formula (b1-1) or a formula (b1-2). ) with a group represented, more preferably a group represented by the formula (b1-1), even more preferably _{* -CO-O- (CH 2)} n - (* is, -C (R ¹ ) represents a bond with (R ² ) —, and n represents 0 or 1.). In addition, Formula (b1-1)-Formula (b1-6) have described the right and left according to Formula (I), and are each represented by the following formula among two bonds shown by *. When the group represents L ¹ , the left bond is bonded to the carbon atom of C (R ¹ ) (R ² ), and the right bond is bonded to Y. The same applies to specific examples of the following formulas (b1-1) to (b1-6).

In formula (b1-1) to formula (b1-6),
L ^b2 represents a single bond or a divalent saturated hydrocarbon group having 1 to 15 carbon atoms.
L ^b3 represents a single bond or a divalent saturated hydrocarbon group having 1 to 12 carbon atoms.
L ^b4 represents a divalent saturated hydrocarbon group having 1 to 13 carbon atoms. However, the upper limit of the total carbon number of L ^b3 and L ^b4 is 13.
L ^b5 represents a divalent saturated hydrocarbon group having 1 to 15 carbon atoms.
L ^b6 represents a single bond or a divalent saturated hydrocarbon group having 1 to 15 carbon atoms.
L ^b7 represents a divalent saturated hydrocarbon group having 1 to 15 carbon atoms. However, the upper limit of the total carbon number of L ^b6 and L ^b7 is 16.
L ^b8 represents a divalent saturated hydrocarbon group having 1 to 14 carbon atoms.
L ^b9 and L ^b10 each independently represent a divalent saturated hydrocarbon group having 1 to 11 carbon atoms. However, the upper limit of the total carbon number of L ^b9 and L ^b10 is 12.
Among these, as the acid generator used in the resist composition of the present invention, a salt (I) having a divalent group represented by the formula (b1-1) as L ¹ is preferable, and L ^b2 is a single bond or A salt (I) having a divalent group represented by the formula (b1-1) which is a methylene group as L ¹ is more preferable.

Here, specific examples of divalent groups respectively represented by formula (b1-1) to formula (b1-6) are given. The definition of * is as described above.
Examples of the divalent group represented by the formula (b1-1) include the following.

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

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

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

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

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

Examples of L ¹ in which a hydrogen atom is substituted with a fluorine atom include the following.

  Y represents an aliphatic hydrocarbon group having 1 to 18 carbon atoms or an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent.

  As a C1-C18 aliphatic hydrocarbon group represented by Y, an alkyl group is preferable and a C1-C6 alkyl group is more preferable. The alkyl group may be linear or branched.

As a C3-C18 alicyclic hydrocarbon group represented by Y, a cycloalkyl group is preferable and a C3-C12 cycloalkyl group is more preferable. The cycloalkyl group may be monocyclic or polycyclic. Further, a cycloalkyl group is not limited to a cycloalkyl group having a carbon atom only as an atom constituting a ring, and a group formed by bonding an alkyl group having 1 to 12 carbon atoms to a carbon atom of an atom constituting a ring. The alicyclic hydrocarbon group optionally has a substituent. In the present specification, the “alicyclic hydrocarbon group having a substituent” means a group in which a hydrogen atom in the alicyclic hydrocarbon group is substituted with a substituent. Examples of the substituent include a halogen atom (excluding a fluorine atom), a hydroxy group, an alkoxy group having 1 to 12 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, and an aralkyl having 7 to 21 carbon atoms. A group represented by a group, an acyl group having 2 to 4 carbon atoms, a glycidyloxy group or — (CH ₂ ) _j2 —O—CO—R ⁱ¹ (wherein R ⁱ¹ is an aliphatic carbon atom having 1 to 16 carbon atoms) Represents a hydrogen group, an alicyclic hydrocarbon group having 3 to 16 carbon atoms or an aromatic hydrocarbon group having 6 to 18 carbon atoms, j2 represents an integer of 0 to 4). The aromatic hydrocarbon group having 6 to 18 carbon atoms and the aralkyl group having 7 to 21 carbon atoms, which are substituents of the alicyclic hydrocarbon group, include, for example, an alkyl group having 1 to 8 carbon atoms, a halogen atom, or a hydroxy group. It may have a group.

When the aliphatic hydrocarbon group or alicyclic hydrocarbon group represented by Y includes a methylene group, the methylene group may be replaced with an oxygen atom, a sulfonyl group (—SO ₂ —), or a carbonyl group. Examples of the group in which the methylene group constituting the alicyclic hydrocarbon group is replaced by an oxygen atom, a sulfonyl group or a carbonyl group include a cyclic ether group (one of the methylene groups contained in the alicyclic hydrocarbon group). Or a group in which two are replaced by oxygen atoms), a cyclic ketone group (a group in which one or two of the methylene groups contained in the alicyclic hydrocarbon group are replaced by carbonyl groups), or a sultone ring group (included in the alicyclic group). Two adjacent methylene groups in the methylene group are groups in which oxygen atoms and sulfonyl groups are substituted, respectively, and lactone ring groups (two adjacent methylene groups in the methylene groups contained in the alicyclic group are oxygen atoms, respectively. And groups in which atoms and carbonyl groups are substituted).

Ｙとしては、これらの例示の中でも、式（Ｙ１）〜式（Ｙ１９）及び式（Ｙ２７）〜式（Ｙ２９）のいずれかで表される基が好ましく、式（Ｙ１１）、式（Ｙ１４）、式（Ｙ１５）、式（Ｙ１９）、式（Ｙ２７）、式（Ｙ２８）又は式（Ｙ２９）で表される基がより好ましく、式（Ｙ１１）又は式（Ｙ１４）で表される基がさらに好ましい。 Examples of the alicyclic hydrocarbon group for Y include groups represented by any of formulas (Y1) to (Y29). Here, the groups represented by the formula (Y12) to the formula (Y26) were each replaced by 1 to 3 methylene groups contained in the alicyclic hydrocarbon group with an oxygen atom, a sulfonyl group, or a carbonyl group. It corresponds to the group. In the groups represented by these formulas (Y1) to (Y29), * represents a bond to L ¹ .

Among these examples, Y is preferably a group represented by any one of formula (Y1) to formula (Y19) and formula (Y27) to formula (Y29). Formula (Y11), formula (Y14), A group represented by formula (Y15), formula (Y19), formula (Y27), formula (Y28) or formula (Y29) is more preferred, and a group represented by formula (Y11) or formula (Y14) is more preferred. .

Examples of the alicyclic hydrocarbon group having a hydroxy group include the following.

Examples of the alicyclic hydrocarbon group having an aromatic hydrocarbon group having 6 to 18 carbon atoms include the following.

Examples of the alicyclic hydrocarbon group having a group represented by — (CH ₂ ) _j2 —O—CO—R ⁱ¹ include the following.

  Y is preferably an adamantyl group which may have a substituent, and more preferably an adamantyl group or a hydroxyadamantyl group.

As the sulfonate anion, a sulfonate anion represented by any one of formulas (b1-1-1) to (b1-1-9) is preferable. R ⁱ² and R ⁱ³ are each independently the same as those exemplified as the substituent that the alicyclic hydrocarbon group represented by Y may have, and an alkyl group having 1 to 4 carbon atoms. And a hydroxy group are preferable, and a methyl group and a hydroxy group are more preferable.

Examples of the sulfonate anion in which Y is an aliphatic hydrocarbon group or an unsubstituted alicyclic hydrocarbon group, and L ¹ is a group represented by the formula (b1-1) include the following. .

A sulfonate anion in which Y is an alicyclic hydrocarbon group having a group represented by — (CH ₂ ) _j2 —O—CO—R ⁱ¹ , and L ¹ is a group represented by the formula (b1-1) For example, the following may be mentioned.

Examples of the sulfonate anion in which Y is an alicyclic hydrocarbon group having a hydroxy group and L ¹ is a group represented by the formula (b1-1) include the following.

As the sulfonate anion, Y is an alicyclic hydrocarbon group having an aromatic hydrocarbon group or an alicyclic hydrocarbon group having an aralkyl group, and L ¹ is a group represented by the formula (b1-1). For example, the following may be mentioned.

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

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

Examples of the sulfonate anion in which Y is a cyclic ketone group and L ¹ is a group represented by the formula (b1-1) include the following.

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

Examples of the sulfonate anion in which Y is an aliphatic hydrocarbon group or an unsubstituted alicyclic hydrocarbon group, and L ¹ is a group represented by the formula (b1-2) include the following. .

A sulfonate anion in which Y is an alicyclic hydrocarbon group having a group represented by — (CH ₂ ) _j2 —O—CO—R ⁱ¹ , and L ¹ is a group represented by the formula (b1-2) For example, the following may be mentioned.

Examples of the sulfonate anion in which Y is an alicyclic hydrocarbon group having a hydroxy group and L ¹ is a group represented by the formula (b1-2) include the following.

Examples of the sulfonate anion in which Y is an alicyclic hydrocarbon group having an aromatic hydrocarbon group and L ¹ is a group represented by the formula (b1-2) include the following.

Examples of the sulfonate anion in which Y is a cyclic ether group and L ¹ is a group represented by the formula (b1-2) include the following.

Examples of the sulfonate anion in which Y is a lactone ring group and L ¹ is a group represented by the formula (b1-2) include the following.

Examples of the sulfonate anion in which Y is a cyclic ketone group and L ¹ is a group represented by the formula (b1-2) include the following.

Examples of the sulfonate anion in which Y is a sultone ring group and L ¹ is a group represented by the formula (b1-2) include the following.

Examples of the sulfonate anion in which Y is an aliphatic hydrocarbon group or an unsubstituted alicyclic hydrocarbon group and L ¹ is a group represented by the formula (b1-3) include the following. .

Examples of the sulfonate anion in which Y is an alicyclic hydrocarbon group having an alkoxy group and L ¹ is a group represented by the formula (b1-3) include the following.

Examples of the sulfonate anion in which Y is an alicyclic hydrocarbon group having a hydroxy group and L ¹ is a group represented by the formula (b1-3) include the following.

Examples of the sulfonate anion in which Y is a cyclic ketone group and L ¹ is a group represented by the formula (b1-3) include the following.

Examples of the sulfonate anion in which Y is an unsubstituted alicyclic hydrocarbon group and L ¹ is a group represented by the formula (b1-4) include the following.

Examples of the sulfonate anion in which Y is an alicyclic hydrocarbon group having an alkoxy group and L ¹ is a group represented by the formula (b1-4) include the following.

Examples of the sulfonate anion in which Y is an alicyclic hydrocarbon group having a hydroxy group and L ¹ is a group represented by the formula (b1-4) include the following.

Examples of the sulfonate anion in which Y is a cyclic ketone group and L ¹ is a group represented by the formula (b1-4) include the following.

Among the sulfonic acid anions exemplified above, those in which L ¹ is a group represented by the formula (b1-1) are preferable. More preferred sulfonate anions are shown below.

Z ¹⁺ is an organic cation having one or more pyridine rings.
Examples of such organic cations include organic onium cations such as organic sulfonium cations, organic iodonium cations, organic ammonium cations, benzothiazolium cations, and organic phosphonium cations. Among these, an organic sulfonium cation or an organic iodonium cation is preferable, an organic sulfonium cation is more preferable, and an arylsulfonium cation is more preferable.

Examples of Z ¹⁺ include the following cations.

［式（Ｉ−Ｚ^１−１）中、
Ｒ^３及びＲ^４は、それぞれ独立に、水素原子、ハロゲン原子、ヒドロキシ基、シアノ基、炭素数１〜１０のアルキル基、炭素数１〜４のアルコキシ基又は炭素数２〜５のアシル基を表す。］
Ｒ^３及びＲ^４で示される炭素数１〜１０のアルキル基としては、例えば、メチル基、エチル基、プロピル基、ブチル基等が挙げられる。好ましくはメチル基又はブチル基である。
炭素数１〜４のアルコキシ基としては、例えば、メトキシ基、エトキシ基、プロポキシ基、ブトキシ基が挙げられる。好ましくはメトキシ基又はブトキシ基である。
炭素数２〜５のアシル基としては、例えば、アセチル基、ベンジル基が挙げられる。好ましくはアセチル基である。 An organic cation represented by the formula (I-Z ¹ -1) is preferred.

[In the formula (I-Z ¹ -1),
R ³ and R ⁴ each independently represent a hydrogen atom, a halogen atom, a hydroxy group, a cyano group, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or an acyl group having 2 to 5 carbon atoms. To express. ]
Examples of the alkyl group having 1 to 10 carbon atoms represented by R ³ and R ^4, for example, a methyl group, an ethyl group, a propyl group, a butyl group. A methyl group or a butyl group is preferred.
Examples of the alkoxy group having 1 to 4 carbon atoms include a methoxy group, an ethoxy group, a propoxy group, and a butoxy group. A methoxy group or a butoxy group is preferable.
Examples of the acyl group having 2 to 5 carbon atoms include an acetyl group and a benzyl group. Preferably it is an acetyl group.

Among these, an organic cation represented by the formula (I-Z ¹ -1-1) is more preferable.

  As salt (I), the salt which consists of a sulfonate anion and organic cation of the following Tables 1-3 is mentioned, for example.

Of these, the salts shown below are preferred.

（式中、Ｒ^１、Ｒ^２、Ｌ^１及びＹは、それぞれ前記と同義である。Ｘはハロゲン原子を表す。）
溶剤としては、クロロホルム等が挙げられる。
式（Ｉａ−ｂ）で表される塩としては、例えば特開２００８−２０９９１７号公報に記載された方法によって製造することができる。 Next, the manufacturing method of salt (I) is demonstrated.
For example, the salt represented by the formula (Ia) can be produced by reacting the salt represented by the formula (Ia-a) with the salt represented by the formula (Ia-b) in a solvent. .

(In the formula, R ¹ , R ² , L ¹ and Y have the same meanings as described above. X represents a halogen atom.)
Examples of the solvent include chloroform.
As a salt represented by a formula (Ia-b), it can manufacture by the method described in Unexamined-Japanese-Patent No. 2008-209917, for example.

（式中、Ｘは、それぞれ上記と同じ意味を表す。）
溶剤としては、テトラヒドロフラン等が挙げられる。 The salt represented by the formula (Ia-a) is obtained by reacting the compound represented by the formula (I1-d) with the compound represented by the formula (I1-e) in the presence of trimethylsilyl halide in a solvent. Can be manufactured.

(In the formula, each X represents the same meaning as described above.)
Tetrahydrofuran etc. are mentioned as a solvent.

酸化剤としては、過酸化水素等が挙げられる。
溶剤としては、アセトン等が挙げられる。 The compound represented by the formula (I1-d) can be produced by reacting the compound represented by the formula (I1-c) in a solvent in the presence of an oxidizing agent.

Examples of the oxidizing agent include hydrogen peroxide.
Acetone etc. are mentioned as a solvent.

触媒としては、カリウムｔ−ブトキシド、テトラキス(トリフェニルホスフィン)パラジウム（０）等が挙げられる。
溶剤としては、エタノール等が挙げられる。 The compound represented by the formula (I1-c) is produced by reacting the compound represented by the formula (I1-a) and the compound represented by the formula (I1-b) in a solvent in the presence of a catalyst. can do.

Examples of the catalyst include potassium t-butoxide, tetrakis (triphenylphosphine) palladium (0), and the like.
Examples of the solvent include ethanol.

<Acid generator>
The acid generator of the present invention contains a salt (I). When the salt (I) is used as an acid generator, it may be used alone or in combination. In addition, the acid generator of the present invention further includes a salt known as an acid generator other than the salt (I) (for example, an organic cation contained in the salt (I) and a known anion (sulfone contained in the salt (I)). A salt composed of an anion other than the acid anion), a sulfonate anion contained in the salt (I), and a known cation (such as a salt composed of a cation other than the organic cation contained in the salt (I)). Hereinafter, salts other than the salt (I) contained in the acid generator of the present invention may be referred to as “acid generator (B)”.

  Examples of the acid generator (B) used in combination with the salt (I) include a compound comprising a sulfonate anion and a triarylsulfonium cation contained in the salt (I). For example, what is represented by Formula (B1-1)-Formula (B1-17) is mentioned. Among them, those containing a triphenylsulfonium cation and a tolylsulfonium cation are preferable. Formula (B1-1), Formula (B1-2), Formula (B1-3), Formula (B1-6), and Formula (B1-7) And salts represented by formula (B1-11), formula (B1-12), formula (B1-13) or formula (B1-14), respectively.

  When the acid generator of the present invention contains the salt (I) and the acid generator (B), the content of the salt (I) is preferably 10 parts by mass or more with respect to 100 parts by mass of the total amount of the acid generator ( More preferably, it is 30 parts by mass or more), preferably 90 parts by mass or less (more preferably 70 parts by mass or less).

<Resist composition>
Next, the resist composition of the present invention will be described. The resist composition of the present invention comprises the acid generator of the present invention and a resin, and the resin has an acid-labile group and is a resin that is insoluble or hardly soluble in an alkaline aqueous solution. It is a resin (hereinafter referred to as “resin (A)”) that can be dissolved in an alkaline aqueous solution by action.

<Resin (A)>
The resin (A) is insoluble or hardly soluble in an alkaline aqueous solution, and has a characteristic of being soluble in an alkaline aqueous solution by the action of an acid. “Becomes soluble in an alkaline aqueous solution by the action of an acid” means insoluble or hardly soluble in an alkaline aqueous solution before contact with an acid, but becomes soluble in an alkaline aqueous solution after contact with an acid. . In such a resin (A), a part or all of the hydrophilic group in the molecule is protected by a protecting group that can be removed by contact with an acid, and the resin (A) is in contact with an acid. Then, the protective group is eliminated and a hydrophilic group is generated, so that the resin (A) becomes soluble in an alkaline aqueous solution. Hereinafter, the hydrophilic group protected by the protecting group may be referred to as an “acid labile group”. Examples of the hydrophilic group include a hydroxy group or a carboxy group, and a carboxy group is more preferable.
The resin (A) can be produced by polymerizing a monomer having an acid labile group (hereinafter referred to as “monomer (a1)”). In the polymerization, only one type of monomer (a1) may be used, or two or more types may be used in combination.

<Monomer (a1)>
As already explained, the monomer (a1) has an acid labile group. The acid labile group in the case where the hydrophilic group is a carboxy group is such that the hydrogen atom of the carboxy group is replaced with an organic residue, and the carbon atom of the organic residue bonded to the oxy group is a tertiary carbon atom. Groups (ie esters of tertiary alcohols). Among such acid labile groups, preferred acid labile groups are, for example, those represented by the following formula (1) (hereinafter sometimes referred to as “acid labile groups (1)”).

In formula (1), R ^{a1 to} R ^a3 each independently represent an alkyl group having 1 to 8 carbon atoms or an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or R ^a1 and R ^a2 are Bond to each other to form a ring having 3 to 20 carbon atoms together with the carbon atom to which they are bonded. When the ring formed by combining R ^a1 and R ^a2 , the alkyl group or the alicyclic hydrocarbon group has a methylene group, the methylene group is replaced by an oxygen atom, a sulfur atom or a carbonyl group. Also good. * Represents a bond.

^Examples of the alkyl group represented by R ^{a1 to} R ^a3 include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, and an octyl group.

Ｒ^a1〜Ｒ^a3の脂環式炭化水素基は、その炭素数が３〜１６の範囲であると好ましい。 The alicyclic hydrocarbon group of R ^{a1 to} R ^a3 may be monocyclic or polycyclic. Examples of the monocyclic alicyclic hydrocarbon group include cycloalkyl groups such as a cyclopentyl group, a cyclohexyl group, a methylcyclohexyl group, a dimethylcyclohexyl group, a cycloheptyl group, and a cyclooctyl group. Examples of the polycyclic alicyclic hydrocarbon group include decahydronaphthyl group, adamantyl group, norbornyl group and methylnorbornyl group, and groups shown below.

The alicyclic hydrocarbon group represented by R ^{a1 to} R ^a3 preferably has 3 to 16 carbon atoms.

When R ^a1 and R ^a2 are bonded to each other to form a ring, examples of the group represented by —C (R ^a1 ) (R ^a2 ) (R ^a3 ) include groups represented by the following formulae. The number of carbon atoms in such a ring is preferably 3-12.

Specific examples of the acid labile group (1) include a 1,1-dialkylalkoxycarbonyl group (a group in which R ^{a1 to} R ^a3 are all alkyl groups in the formula (1), one of these alkyl groups is tert -Butoxycarbonyl group is preferable.), 2-alkyladamantan-2-yloxycarbonyl group (in formula (1), R ^a1 and R ^a2 are bonded to each other, and together with the carbon atom to which they are bonded, an adamantyl ring is formed) 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 adamantyl). Group which is a group).

On the other hand, examples of the acid labile group in the case where the hydrophilic group is a hydroxy group include those in which a hydrogen atom of the hydroxy group is replaced with an organic residue to become a group containing an acetal structure or a ketal structure. Among such acid labile groups, preferred acid labile groups are, for example, those represented by the following formula (2) (hereinafter sometimes referred to as “acid labile groups (2)”).

In formula (2), R ^{b1 to} R ^b2 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, and R ^b3 represents a hydrocarbon group having 1 to 20 carbon atoms, or , R ^b2 and R ^b3 are bonded to each other to form a ring having 3 to 20 carbon atoms together with the carbon atom and the oxygen atom to which they are bonded. When R ^b2 and R ^b3 have a ring formed by bonding to each other or the hydrocarbon group methylene group, the methylene group may be replaced by an oxygen atom, a sulfur atom or a carbonyl group. * Represents a bond.

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

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

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

  The monomer (a1) is preferably a monomer having both an acid labile group (1) and / or an acid labile group (2) and a carbon-carbon double bond in the molecule, and the acid labile group (1 ) And / or an acid labile group (2) and a (meth) acryl group in the molecule, more preferably a (meth) acrylic monomer having an acid labile group (1). It is.

  Among the (meth) acrylic monomers having an acid labile group (1), those having an acid labile group (1) having an aliphatic ring having 5 to 20 carbon atoms are preferred. If a resist pattern is produced using this resist composition containing the resin (A) obtained by polymerizing the monomer (a1) having a sterically bulky aliphatic ring, the resist pattern can be produced with higher resolution. Can do.

式（ａ１−１）及び式（ａ１−２）中、
Ｌ^a1及びＬ^a2は、それぞれ独立に、酸素原子又は＊−Ｏ−（ＣＨ₂）_k1−ＣＯ−Ｏ−で表される基を表す。ここで、ｋ１は１〜７の整数を表し、＊はカルボニル基（−ＣＯ−）との結合手である。
Ｒ^a4及びＲ^a5は、それぞれ独立に、水素原子又はメチル基を表す。
Ｒ^a6及びＲ^a7は、それぞれ独立に、炭素数１〜８のアルキル基又は炭素数３〜１０の脂環式炭化水素基を表す。
ｍ１は０〜１４の整数を表す。
ｎ１は０〜１０の整数を表す。
ｎ２は０又は１の整数を表す。
なお、式（ａ１−１）においてアダマンタン環にある「−（ＣＨ_３）_ｍ１」の表記は、アダマンタン環にあるメチレン基及び／又はメチン基の水素原子が、メチル基に置き換わっており、アダマンタン環に結合しているメチル基の個数がｍ１個であることを意味する。 Among (meth) acrylic monomers having an acid labile group (1) having a partial structure of an aliphatic ring, a monomer represented by the formula (a1-1) (hereinafter referred to as “monomer (a1-1)”) Or a monomer represented by formula (a1-2) (hereinafter may be referred to as “monomer (a1-2)”). When manufacturing resin (A), these may be used independently and may use 2 or more types together.

In formula (a1-1) and formula (a1-2),
L ^a1 and L ^a2 each independently represent an oxygen atom or a group represented by * —O— (CH ₂ ) _k1 —CO—O—. Here, k1 represents an integer of 1 to 7, and * is a bond with a carbonyl group (—CO—).
R ^a4 and R ^a5 each independently represent a hydrogen atom or a methyl group.
R ^a6 and R ^a7 each independently represent an alkyl group having 1 to 8 carbon atoms or an alicyclic hydrocarbon group having 3 to 10 carbon atoms.
m1 represents the integer of 0-14.
n1 represents an integer of 0 to 10.
n2 represents an integer of 0 or 1.
In addition, in the formula (a1-1), the notation “— (CH ₃ ) _m1 ” in the adamantane ring means that the hydrogen atom of the methylene group and / or methine group in the adamantane ring is replaced with a methyl group, This means that the number of methyl groups bonded to is m1.

ｍ１は、好ましくは０〜３の整数、より好ましくは０又は１である。
ｎ１は、好ましくは０〜３の整数、より好ましくは０又は１である。
＊は、アダマンタン環又はシクロヘキサン環との結合手を表す。 L ^a1 and L ^a2 are preferably an oxygen atom or * —O— (CH ₂ ) _f1 —CO—O— (where f1 represents an integer of 1 to 4, * represents a carbonyl group (—CO—) and A group represented by formula (1), and more preferably an oxygen atom. f1 is more preferably 1.
R ^a4 and R ^a5 are preferably methyl groups.
Examples of the aliphatic hydrocarbon group for R ^a6 and R ^a7 include an alkyl group, and more specifically, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, and an octyl group. Groups and the like. The alkyl group for R ^a6 or R ^a7 is preferably a group having 6 or less carbon atoms. The alicyclic hydrocarbon group for R ^a6 or R ^a7 preferably has 8 or less carbon atoms, more preferably 6 or less.
When R ^a6 or R ^a7 is an alicyclic hydrocarbon group, the alicyclic hydrocarbon group may be monocyclic or polycyclic. Examples of the monocyclic alicyclic hydrocarbon group include cycloalkyl groups such as a cyclopentyl group, a cyclohexyl group, a methylcyclohexyl group, a dimethylcyclohexyl group, a cycloheptyl group, and a cyclooctyl group. Examples of the polycyclic alicyclic hydrocarbon group include a decahydronaphthyl group, an adamantyl group, a norbornyl group, a methylnorbornyl group, and the following groups.

m1 is preferably an integer of 0 to 3, more preferably 0 or 1.
n1 is preferably an integer of 0 to 3, more preferably 0 or 1.
* Represents a bond with an adamantane ring or a cyclohexane ring.

Examples of the monomer represented by the formula (a1-1) include monomers described in JP 2010-204646 A. Monomers represented by the following formulas (a1-1-1) to (a1-1-6) are preferred, and monomers represented by the following formulas (a1-1-1) to (a1-1-3) are more preferred. .

Examples of the monomer represented by the formula (a1-2) include 1-ethylcyclopentan-1-yl (meth) acrylate, 1-ethylcyclohexane-1-yl (meth) acrylate, 1-ethylcycloheptane-1 -Yl (meth) acrylate, 1-methylcyclopentan-1-yl (meth) acrylate, 1-isopropylcyclopentan-1-yl (meth) acrylate and the like. Monomers represented by the following formulas (a1-2-1) to (a1-2-6) are preferred, and monomers represented by the following formulas (a1-2-3) to (a1-2-4) are more preferred. A monomer represented by the following formula (a1-2-3) is more preferable.

  When the resin (A) is produced using the monomer (a1-1) and / or the monomer (a1-2), when the total structural unit of the obtained resin (A) is 100 mol%, it is derived from these monomers. The total content of structural units is preferably in the range of 10 to 95 mol%, more preferably in the range of 15 to 90 mol%, and still more preferably in the range of 20 to 85 mol%. In order to bring the total content of the structural unit derived from the monomer (a1-1) and / or the structural unit derived from the monomer (a1-2) into such a range, when producing the resin (A) In addition, the amount of the monomer (a1-1) and / or the monomer (a1-2) used may be adjusted with respect to the amount of all the monomers used.

  As described above, the (meth) acrylic monomer suitable as the monomer (a1) has been described. For the production of the resin (A), in addition to the (meth) acrylic monomer, an acid labile group (1) and carbon-carbon are used. Other monomers having a double bond in the molecule can also be used. Hereinafter, typical examples of such other monomers will be described.

式（ａ１−３）中、
Ｒ^a9は、水素原子、ヒドロキシ基を有していてもよい炭素数１〜３のアルキル基、カルボキシ基、シアノ基又は−ＣＯＯＲ^a13を表す。
Ｒ^a13は、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、炭素数１〜８のアルキル基と炭素数３〜２０の脂環式炭化水素基とからなる基を表し、該アルキル基及び該脂環式炭化水素基に含まれる水素原子は、ヒドロキシ基で置換されていてもよく、該アルキル基及び該脂環式炭化水素基にを構成しているメチレン基は、酸素原子又はカルボニル基で置き換わっていてもよい。
Ｒ^a10、Ｒ^a11及びＲ^a12は、それぞれ独立に、炭素数１〜１２のアルキル基又は炭素数３〜２０の脂環式炭化水素基を表すか、或いは、Ｒ^a10及びＲ^a11が互いに結合して、これらが結合している炭素原子とともに、炭素数３〜２０の環を形成している。該アルキル基及び該脂環式炭化水素基に含まれる水素原子は、ヒドロキシ基等で置換されていてもよく、該脂肪族炭化水素基及び該脂環式炭化水素基を構成しているメチレン基は、酸素原子又はカルボニル基で置き換わっていてもよい。 Furthermore, as a monomer having both an acid labile group (1) and a carbon-carbon double bond in the molecule, for example, a monomer having a norbornene ring represented by the following formula (a1-3) (hereinafter referred to as “monomer ( a1-3) ”)).

In formula (a1-3),
R ^a9 represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms which may have a hydroxy group, a carboxy group, a cyano group or —COOR ^a13 .
R ^a13 is an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or an alkyl group having 1 to 8 carbon atoms and an alicyclic hydrocarbon group having 3 to 20 carbon atoms. A hydrogen atom contained in the alkyl group and the alicyclic hydrocarbon group may be substituted with a hydroxy group, and constitutes the alkyl group and the alicyclic hydrocarbon group. The methylene group may be replaced with an oxygen atom or a carbonyl group.
R ^a10 , R ^a11 and R ^a12 each independently represents an alkyl group having 1 to 12 carbon atoms or an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or R ^a10 and R ^a11 are bonded to each other. Thus, a ring having 3 to 20 carbon atoms is formed together with the carbon atom to which they are bonded. A hydrogen atom contained in the alkyl group and the alicyclic hydrocarbon group may be substituted with a hydroxy group or the like, and the methylene group constituting the aliphatic hydrocarbon group and the alicyclic hydrocarbon group May be replaced by an oxygen atom or a carbonyl group.

^Examples of —COOR ^a13 for R ^a9 include groups in which a carbonyl group is bonded to an alkoxy group such as a methoxycarbonyl group and an ethoxycarbonyl group.

Examples of the alkyl group which may have a hydroxy group of R ^a9 include a methyl group, an ethyl group, a propyl group, a hydroxymethyl group and a 2-hydroxyethyl group.
^Examples of the group ^consisting of an alkyl group represented by R ^a13 , an alicyclic hydrocarbon group, and an alkyl group having 1 to 8 carbon atoms and an alicyclic hydrocarbon group having 3 to 20 carbon atoms include, for example, a methyl group, an ethyl group, and propyl Group, cyclopentyl group, cyclopropyl group, adamantyl group, adamantylmethyl group, 1-adamantyl-1-methylethyl group, 2-oxo-oxolan-3-yl group and 2-oxo-oxolan-4-yl group It is done.
Examples of R ^{a10 to} R ^a12 include a methyl group, an ethyl group, a cyclohexyl group, a methylcyclohexyl group, a hydroxycyclohexyl group, an oxocyclohexyl group, and an adamantyl group.
The ring formed by combining R ^a10 and R ^a11 with each other is preferably an aliphatic ring, and specific examples include a cyclohexane ring and an adamantane ring.

  Specific examples of the monomer (a1-3) include: 5-norbornene-2-carboxylic acid-tert-butyl, 5-norbornene-2-carboxylic acid 1-cyclohexyl-1-methylethyl, 5-norbornene-2-carboxylic acid Acid 1-methylcyclohexyl, 5-norbornene-2-carboxylic acid 2-methyl-2-adamantyl, 5-norbornene-2-carboxylic acid 2-ethyl-2-adamantyl, 5-norbornene-2-carboxylic acid 1- (4 -Methylcyclohexyl) -1-methylethyl, 5-norbornene-2-carboxylic acid 1- (4-hydroxycyclohexyl) -1-methylethyl, 5-norbornene-2-carboxylic acid 1-methyl-1- (4-oxo Cyclohexyl) ethyl and 5-norbornene-2-carboxylic acid 1- (1-adamantyl) -1- Chiruechiru, and the like.

  When the resin (A) is produced using the monomer (a1-3), the resin (A) includes a sterically bulky structural unit derived from the monomer (a1-3). If a resist pattern is manufactured using this resist composition containing resin (A) which has this structural unit, a resist pattern can be obtained with higher resolution. Furthermore, since a rigid norbornane ring can be introduced into the main chain of the resin (A) by using the monomer (a1-3), the resist pattern obtained from the resist composition containing the resin (A) has a dry etching resistance. Tend to be better.

  As described above, the monomer (a1) relative to the total structural unit (100 mol%) of the resin (A) is that the resist pattern can be produced with good resolution and that a resist pattern excellent in dry etching resistance can be easily obtained. The content of the structural unit derived from -3) is preferably in the range of 10 to 95 mol%, more preferably in the range of 15 to 90 mol%, and still more preferably in the range of 20 to 85 mol%.

［式（ａ１−４）中、
Ｒ^a32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^a33は、ハロゲン原子、ヒドロキシ基、炭素数１〜６のアルキル基、炭素数１〜６のアルコキシ基、炭素数２〜４のアシル基、炭素数２〜４のアシルオキシ基、アクリロイル基又はメタクリロイル基を表す。
ｌａは０〜４の整数を表す。ｌａが２以上である場合、複数のＲ^a33は互いに同一であっても異なってもよい。
Ｒ^a34及びＲ^a35はそれぞれ独立に、水素原子又は炭素数１〜１２の炭化水素基を表す。
Ｘ^a2は、単結合又は２価の炭素数１〜１７の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、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のアシル基又は炭素数２〜４のアシルオキシ基で置換されていてもよく、該飽和炭化水素基にメチレン基が含まれる場合、そのメチレン基は、カルボニル基、酸素原子、硫黄原子、スルホニル基（−ＳＯ_２−）又は−Ｎ（Ｒ^ｃ）−で表される基で置き換わっていてもよい。ここで、Ｒ^ｃは、水素原子又は炭素数１〜６のアルキル基を表す。
Ｙ^a3は、炭素数１〜１２のアルキル基、炭素数３〜１８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を表し、該アルキル基、該脂環式炭化水素基及び該芳香族炭化水素基の各々に含まれる水素原子は、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のアシル基又は炭素数２〜４のアシルオキシ基で置換されていてもよい。］ As a monomer having both an acid labile group (2) and a carbon-carbon double bond in the molecule, a monomer represented by the following formula (a1-4) (hereinafter referred to as “monomer (a1-4)”) May also be used).

[In the formula (a1-4),
R ^a32 represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom.
R ^a33 is a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an acyl group having 2 to 4 carbon atoms, an acyloxy group having 2 to 4 carbon atoms, an acryloyl group, or methacryloyl. Represents a group.
la represents an integer of 0 to 4. When la is 2 or more, the plurality of R ^a33 may be the same as or different from each other.
R ^a34 and R ^a35 each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms.
X ^a2 represents a single bond or a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group is a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, When the methylene group is contained in the saturated hydrocarbon group, the methylene group may be substituted with an alkoxy group having 1 to 6 carbon atoms, an acyl group having 2 to 4 carbon atoms, or an acyloxy group having 2 to 4 carbon atoms. May be replaced by a group represented by a carbonyl group, an oxygen atom, a sulfur atom, a sulfonyl group (—SO ₂ —) or —N (R ^c ) —. Here, R ^c represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
Y ^a3 represents an alkyl group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms, and the alkyl group or the alicyclic hydrocarbon group. Group and each aromatic hydrocarbon group include a hydrogen atom, 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, or It may be substituted with an acyloxy group having 2 to 4 carbon atoms. ]

^Examples of the alkyl group for R ^a32 and R ^a33 include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a pentyl group, and a hexyl group. When R ^a32 and R ^a33 are alkyl groups, an alkyl group having 1 to 4 carbon atoms is preferable, a methyl group or an ethyl group is more preferable, and a methyl group is further preferable.
Examples of the halogen atom for R ^a32 and R ^a33 include a fluorine atom, a chlorine atom, and a bromine atom.
Examples of the alkyl group ^optionally having a halogen atom of R ^a32 include a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group, and a perfluorotert-butyl group. Perfluoropentyl group, perfluorohexyl group, trichloromethyl group, tribromomethyl group, triiodomethyl group and the like.
Examples of the alkoxy group for R ^a33 include methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, sec-butoxy group, tert-butoxy group, n-pentoxy group and n-hexoxy group. Can be mentioned.
Examples of the acyl group for R ^a33 include an acetyl group, a propionyl group, and a butyryl group.
Examples of the acyloxy group for R ^a33 include an acetyloxy group, a propionyloxy group, and a butyryloxy group.
Examples of the hydrocarbon group R ^a34 and R ^a35, for example, an alkyl group, alicyclic hydrocarbon group and aromatic hydrocarbon group. The alkyl group includes those described as the alkyl groups of R ^a6 and R ^a7 of the monomer (a1-1) except that the upper limit of the carbon number is different, and specific examples thereof are also exemplified as the alkyl groups of R ^a6 and R ^a7. Including As the alkyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, octyl group and 2-ethylhexyl group are preferable. The alicyclic hydrocarbon group includes those described as the alicyclic hydrocarbon groups of R ^a6 and R ^a7 of the monomer (a1-1) except that the upper limit of the carbon number is different, and specific examples thereof are also R ^a6. And those exemplified as the alicyclic hydrocarbon group for R ^a7 . As the alicyclic hydrocarbon group, a cyclohexyl group, an adamantyl group, a 2-alkyladamantan-2-yl group, a 1- (adamantan-1-yl) alkane-1-yl group, an isobornyl group, and the like are preferable. The aromatic hydrocarbon group is typically an aryl group, specifically, a phenyl group, a naphthyl group, an anthryl group, a p-methylphenyl group, a p-tert-butylphenyl group, a p-adamantylphenyl group. , Tolyl group, xylyl group, cumenyl group, mesityl group, biphenyl group, phenanthryl group, 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl and the like.

R ^a32 and R ^a33 are preferably an alkyl group having 1 to 4 carbon atoms, more preferably a methyl group or an ethyl group, and particularly preferably a methyl group.
R ^a33 is more preferably a methoxy group or an ethoxy group, and particularly preferably a methoxy group.
The R ^a34 and R ^a35, isopropyl group, n- butyl group, sec- butyl group, tert- butyl group, a pentyl group, a hexyl group, an octyl group, a 2-ethylhexyl group, a cyclohexyl group, an adamantyl group, 2-alkyl - A 2-adamantyl group, a 1- (1-adamantyl) -1-alkyl group, an isobornyl group, and the like are preferable.

As described above, X ^a2 and Y ^a3 may have a hydrogen atom contained therein substituted by a halogen atom, a hydroxy group, or the like. When a hydrogen atom is substituted in this way, the substituent is A hydroxy group is preferred.

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

  When the resin (A) has a structural unit derived from the monomer (a1-4), the content thereof is in the range of 10 to 95 mol% with respect to all the structural units (100 mol%) of the resin (A). Is preferable, the range of 15-90 mol% is more preferable, and the range of 20-85 mol% is further more preferable.

式（ａ１−５）中、
Ｒ³¹としては、Ｒ^５と同じものが挙げられ、水素原子又はメチル基であることが好ましい。
Ｌ^２及びＬ^３は、一方が酸素原子、他方が硫黄原子であることが好ましい。
Ｌ^４は、酸素原子又は硫黄原子であり、酸素原子が好ましい。
ｓ１は、１が好ましい。
ｓ２は、０〜２の整数が好ましい。
Ｚ^１は、単結合、＊−（ＣＨ_２）_n4−Ｏ−又は＊−（ＣＨ_２）_n4−ＣＯ−Ｏ−（各ｎ４は１〜４の整数であり、１が好ましい。各＊は、Ｌ^４との結合手を表す。）である。 Furthermore, as a monomer having both an acid labile group (2) and a carbon-carbon double bond in the molecule, a monomer represented by the formula (a1-5) (hereinafter referred to as “monomer (a1-5)”) In some cases).

In formula (a1-5),
R ³¹ may be the same as R ^5, and is preferably a hydrogen atom or a methyl group.
One of L ² and L ³ is preferably an oxygen atom and the other is a sulfur atom.
L ⁴ is an oxygen atom or a sulfur atom, preferably an oxygen atom.
s1 is preferably 1.
s2 is preferably an integer of 0 to 2.
Z ¹ is a single bond, * — (CH ₂ ) _n4 —O— or * — (CH ₂ ) _n4 —CO—O— (each n4 is an integer of 1 to 4, and is preferably 1. Each * is represents a bond to L ^4.) it is.

As a monomer (a1-5), the following are mentioned, for example.

  When the resin (A) has a structural unit derived from the monomer (a1-5), the content thereof is in the range of 10 to 95 mol% with respect to all the structural units (100 mol%) of the resin (A). Is preferable, the range of 15-90 mol% is more preferable, and the range of 20-85 mol% is further more preferable.

<Acid stable monomer>
The resin (A) is preferably a copolymer obtained by using a monomer having no acid labile group (hereinafter sometimes referred to as “acid-stable monomer”) in addition to the monomer (a1). In addition, as an additive used in the resist composition, a resin obtained from an acid stable monomer may be used.

  When the resin (A) is produced by using an acid-stable monomer in combination, the amount of the acid-stable monomer may be determined based on the amount of the monomer (a1) used. The ratio of the amount of monomer (a1) used and the amount of acid-stable monomer used is represented by [monomer (a1)] / [acid-stable monomer], preferably 10 to 80 mol% / 90 to 20 mol%, More preferably, it is 20-60 mol% / 80-40 mol%. Moreover, when using the monomer (especially monomer (a1-1)) which has an adamantyl group for a monomer (a1), it has an adamantyl group with respect to the total amount (100 mol%) of this monomer (a1) usage-amount. The amount of the monomer used is preferably 15 mol% or more. If it does in this way, there exists a tendency for the dry etching tolerance of the resist pattern obtained from the resist composition containing resin (A) to become more favorable.

  As the acid stable monomer, those having a hydroxy group or a lactone ring in the molecule are preferable. Acid-stable monomer having a hydroxy group (hereinafter sometimes referred to as “acid-stable monomer (a2)”) and / or acid-stable monomer having a lactone ring (hereinafter referred to as “acid-stable monomer (a3)”) The resin (A) having a structural unit derived from.) Is a coating film formed on the substrate or a composition layer obtained from the coating film when a resist composition containing the resin (A) is applied to the substrate. Since the adhesion between the substrate and the substrate is excellent, a resist pattern can be manufactured with high resolution.

<Acid stable monomer (a2)>
When this resist composition is used for KrF excimer laser exposure (wavelength: 248 nm), high energy beam exposure such as electron beam or EUV light, the acid stable monomer having a phenolic hydroxy group as the acid stable monomer (a2) It is preferable to use (a2-0) [for example, hydroxystyrenes] for the production of the resin (A).
On the other hand, when short-wave ArF excimer laser exposure (wavelength: 193 nm) is used, an acid-stable monomer represented by the formula (a2-1) described later is used as the acid-stable monomer (a2) in the production of the resin (A). It is preferable to use it. As described above, the acid-stable monomer (a2) used for the production of the resin (A) can be preferably selected depending on the exposure source used for producing the resist pattern. The acid-stable monomer (a2) The resin (A) may be produced using only one kind of monomer suitable for the kind of the resin, or the resin (A) may be produced using two or more kinds of suitable monomers for the kind of the exposure source. Alternatively, the resin (A) may be produced by using two or more types in combination of a suitable monomer according to the type of the exposure source and the other acid stable monomer (a2).

［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、アクリロイル基又はメタクリロイル基を表す。
ｍａは０〜４の整数を表す。ｍａが２以上の整数である場合、複数のＲ^a31は互いに同一であっても異なってもよい。］ The acid stable monomer (a2) may be referred to as a styrene monomer such as p- or m-hydroxystyrene represented by the following formula (a2-0) (hereinafter referred to as “acid stable monomer (a2-0)”). .). In addition, this formula (a2-0) is shown in a form in which the phenolic hydroxy group is not protected by a protecting group.

[In the formula (a2-0),
R ^a30 represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have 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 acryloyl group, or methacryloyl. Represents a group.
ma represents an integer of 0 to 4. When ma is an integer of 2 or more, the plurality of R ^a31 may be the same as or different from each other. ]

^Examples of the halogen atom of R ^a30 and the alkyl group having 1 to 6 carbon atoms which may have a halogen atom include the same groups as those exemplified in the description of R ^a32 of the monomer (a1-4). Among these, R ^a30 is preferably an alkyl group having 1 to 4 carbon atoms, more preferably a methyl group or an ethyl group, and further preferably a methyl group.
As the alkyl group for R ^a31 , an alkyl group having 1 to 4 carbon atoms is preferable, an alkyl group having 1 or 2 carbon atoms is more preferable, and a methyl group is further preferable.
Examples of the alkoxy group for R ^a31 include the same groups as those exemplified in the description of R ^a33 of the monomer (a1-4). Among these, R ^a31 is preferably an alkoxy group having 1 to 4 carbon atoms, more preferably a methoxy group or an ethoxy group, and further preferably a methoxy group.
ma is preferably 0, 1 or 2, more preferably 0 or 1, and still more preferably 0.

  When obtaining a copolymer resin having a structural unit derived from such an acid-stable monomer (a2-0), radical polymerization of the corresponding (meth) acrylic acid ester monomer and acetoxystyrene and / or other polymerizable monomer And then deacetylated with a base.

As an acid stable monomer (a2-0), the monomer described in Unexamined-Japanese-Patent No. 2010-204634 is mentioned, for example. Monomers represented by the following formulas (a2-0-1) and (a2-0-2) are preferred. When manufacturing resin (A), what protected the phenolic hydroxy group in these with the suitable protective group can also be used.

  When the resin (A) has a structural unit derived from the acid-stable monomer (a2-0), the content thereof is 5 to 95 mol% with respect to the total structural unit (100 mol%) of the resin (A). Is preferable, the range of 10 to 80 mol% is more preferable, and the range of 15 to 80 mol% is more preferable.

式（ａ２−１）中、
Ｌ^a3は、酸素原子又は＊−Ｏ−（ＣＨ₂）_k2−ＣＯ−Ｏ−を表し、
ｋ２は１〜７の整数を表す。＊はカルボニル基（−ＣＯ−）との結合手を表す。
Ｒ^a14は、水素原子又はメチル基を表す。
Ｒ^a15及びＲ^a16は、それぞれ独立に、水素原子、メチル基又はヒドロキシ基を表す。
ｏ１は、０〜１０の整数を表す。 The acid stable monomer (a2-1) is represented by the following formula (a2-1).

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

In the formula (a2-1), L ^a3 is preferably an oxygen atom or _{* -O- (CH 2) f2 -CO} -O- ( where f2 is an integer of 1 to 4), more Preferably it is an oxygen atom.
R ^a14 is preferably a methyl group.
R ^a15 is preferably a hydrogen atom.
R ^a16 is preferably a hydrogen atom or a hydroxy group.
o1 is preferably an integer of 0 to 3, more preferably 0 or 1.

As an acid stable monomer (a2-1), the monomer described in Unexamined-Japanese-Patent No. 2010-204646 is mentioned, for example. Monomers represented by the following formulas (a2-1-1) to (a2-1-6) are preferable, respectively, and monomers represented by the following formulas (a2-1-1) to (a2-1-4) are respectively used. More preferred are monomers represented by the following formulas (a2-1-1) or (a2-1-3), respectively.

  When the resin (A) has a structural unit derived from the acid-stable monomer (a2-1), the content thereof is 3 to 40 mol% with respect to the total structural unit (100 mol%) of the resin (A). The range of 5 to 35 mol% is more preferable, the range of 5 to 30 mol% is more preferable, and the range of 5 to 20 mol% is more preferable.

<Acid stable monomer (a3)>
The acid stable monomer (a3) is an acid stable monomer containing a lactone ring. Such a lactone ring may be a monocyclic ring such as a β-propiolactone ring, a γ-butyrolactone ring and a δ-valerolactone ring, or may be a condensed ring of a monocyclic lactone ring and another ring. Among these lactone rings, a γ-butyrolactone ring and a condensed ring of a γ-butyrolactone ring and another ring are preferable.

式（ａ３−１）、式（ａ３−２）及び式（ａ３−３）のいずれか中、
Ｌ^a4、Ｌ^a5及びＬ^a6（以下、「Ｒ^a18〜Ｒ^a20」のように表記する。）は、それぞれ独立に、酸素原子又は＊−Ｏ−（ＣＨ₂）_k3−ＣＯ−Ｏ−を表す。
ｋ３は１〜７の整数を表す。＊は−ＣＯ−との結合手を表す。
Ｒ^a18、Ｒ^a19及びＲ^a20（以下、「Ｒ^a18〜Ｒ^a20」のように表記する。）は、それぞれ独立に、水素原子又はメチル基を表す。
Ｒ^a21は、炭素数１〜４の脂肪族炭化水素基を表す。
ｐ１は０〜５の整数を表す。
Ｒ^a22及びＲ^a23は、それぞれ独立に、カルボキシ基、シアノ基又は炭素数１〜４の脂肪族炭化水素基を表す。
ｑ１及びｒ１は、それぞれ独立に０〜３の整数を表す。
ｐ１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。
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。
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。 The acid stable monomer (a3) is preferably one represented by the following formula (a3-1), formula (a3-2) or formula (a3-3). In manufacture of resin (A), only 1 type may be used among these and 2 or more types may be used together. In the following description, the acid stable monomer (a3) represented by the formula (a3-1) may be referred to as “acid stable monomer (a3-1)”, and the acid stability represented by the formula (a3-2) may be referred to. The monomer (a3) may be referred to as “acid-stable monomer (a3-2)”, and the acid-stable monomer (a3) represented by formula (a3-3) may be referred to as “acid-stable monomer (a3-3)”. .

In any one of formula (a3-1), formula (a3-2) and formula (a3-3),
L ^a4 , L ^a5 and L ^a6 (hereinafter referred to as “R ^{a18 to} R ^a20 ”) each independently represent an oxygen atom or * —O— (CH ₂ ) _k3 —CO—O—. .
k3 represents an integer of 1 to 7. * Represents a bond with -CO-.
R ^a18 , R ^a19 and R ^a20 (hereinafter referred to as “R ^{a18 to} R ^a20 ”) each independently represent a hydrogen atom or a methyl group.
R ^a21 represents an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
p1 represents an integer of 0 to 5.
R ^a22 and R ^a23 each independently represent a carboxy group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
q1 and r1 each independently represents an integer of 0 to 3.
When p1 is 2 or more, the plurality of R ^a21 may be the same as or different from each other.
When q1 is 2 or more, the plurality of R ^a22 may be the same as or different from each other.
When r1 is 2 or more, the plurality of R ^a23 may be the same as or different from each other.

In formula (a3-1) to formula (a3-3), examples of L ^a4 , L ^a5, and L ^a6 include those described for L ^a3 .
L ^a4 , L ^a5 and L ^a6 are each independently preferably an oxygen atom or * —O— (CH ₂ ) _d1 —CO—O— (where d1 is an integer of 1 to 4). More preferably an oxygen atom.
R ^{a18 to} R ^a21 are preferably each independently a methyl group.
R ^a22 and R ^a23 are each independently preferably a carboxy group, a cyano group or a methyl group.
p1, q1 and r1 are each independently preferably an integer of 0 to 2, more preferably 0 or 1.

Examples of the acid stable monomer (a3) include monomers described in JP 2010-204646 A. The following formulas (a3-1-1) to (a3-1-4), (a3-2-1) to (a3-2-4), (a3-3-1) to (a3-3-4), respectively Are preferable, and monomers represented by the following formulas (a3-1-1) to (a3-1-2) and (a3-2-3) to (a3-2-4) are more preferable, respectively. More preferably, monomers represented by the following formula (a3-1-1) or (a3-2-3), respectively.

The resin (A) is a structural unit selected from the group consisting of a structural unit derived from the monomer (a3-1), a structural unit derived from the monomer (a3-2), and a structural unit derived from the monomer (a3-3) [ In the case of having the structural unit derived from the acid-stable monomer (a3)], the total content thereof is preferably from 5 to 60 mol%, more preferably from 5 to 55, based on all structural units (100 mol%) of the resin (A). The range of mol% is more preferable, the range of 10-50 mol% is more preferable, and the range of 15-50 mol% is still more preferable.
The content of each of the structural unit derived from the monomer (a3-1), the structural unit derived from the monomer (a3-2), and the structural unit derived from the monomer (a3-3) is the total structure of the resin (A). 5-60 mol% is preferable with respect to a unit (100 mol%), the range of 10-50 mol% is more preferable, and the range of 15-50 mol% is especially preferable.

<Acid-stable monomer (a4)>
For the production of the resin (A), acid-stable monomers other than the acid-stable monomers described above can also be used. Hereinafter, such an acid stable monomer may be referred to as “acid stable monomer (a4)”.

式（ａ４−３）中、
Ｒ^a25及びＲ^a26は、それぞれ独立に、水素原子、ヒドロキシ基を有していてもよい炭素数１〜３のアルキル基、シアノ基、カルボキシ基又は−ＣＯＯＲ^a27を表すか、或いはＲ^a25及びＲ^a26は互いに結合して−ＣＯ−Ｏ−ＣＯ−を形成する。
Ｒ^a27は、炭素数１〜１８のアルキル基、炭素数３〜２０の脂環式炭化水素基又は炭素数１〜８のアルキル基と炭素数３〜２０の脂環式炭化水素基とからなる基を表す。該アルキル基及び該脂環式炭化水素基を構成しているメチレン基は、酸素原子又はカルボニル基で置き換わっていてもよい。但し−ＣＯＯＲ^a27が酸不安定基となるものは除く（例えば、Ｒ^a27は、第三級炭素原子が−Ｏ−と結合するものを含まない） As the acid stable monomer (a4), maleic anhydride represented by the following formula (a4-1), itaconic anhydride represented by the following formula (a4-2), and formula (a4-3) shown below And an acid-stable monomer having a norbornene ring (hereinafter sometimes referred to as “acid-stable monomer (a4-3)”).

In formula (a4-3),
R ^a25 and R ^a26 each independently represent a hydrogen atom, an alkyl group having 1 to 3 carbon atoms which may have a hydroxy group, a cyano group, a carboxy group or —COOR ^a27 , or R ^a25 and R ^{a26 a26} combine with each other to form —CO—O—CO—.
R ^a27 is ^composed of an alkyl group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or an alkyl group having 1 to 8 carbon atoms and an alicyclic hydrocarbon group having 3 to 20 carbon atoms. Represents a group. The methylene group constituting the alkyl group and the alicyclic hydrocarbon group may be replaced with an oxygen atom or a carbonyl group. However, those in which —COOR ^a27 is an acid labile group are excluded (for example, R ^a27 does not include those in which a tertiary carbon atom is bonded to —O—).

In R ^a25 and R ^a26 of the monomer (a4-3), ^examples of the alkyl group which may have a hydroxy group include a methyl group, an ethyl group, a propyl group, a hydroxymethyl group, and a 2-hydroxyethyl group. Can be mentioned.
The alkyl group for R ^a27 is preferably a group having 1 to 8 carbon atoms, more preferably a group having 1 to 6 carbon atoms. The alicyclic hydrocarbon group is preferably a group having 4 to 18 carbon atoms, more preferably a group having 4 to 12 carbon atoms. ^Examples of R ^a27 include a methyl group, an ethyl group, a propyl group, a cyclopentyl group, a cyclopropyl group, an adamantyl group, an adamantylmethyl group, and 1-adamantyl) -1-methylethyl group, 2-oxo-oxolane-3- Yl group and 2-oxo-oxolan-4-yl group.

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

  The resin (A) is a structural unit derived from maleic anhydride represented by the formula (a4-1), a structural unit derived from itaconic anhydride represented by the formula (a4-2), and a monomer (a4-3). In the case where it has a structural unit selected from the group consisting of structural units derived from (a structural unit derived from an acid-stable monomer (a4)), the total content is based on all structural units (100 mol%) of the resin (A). On the other hand, the range of 2-40 mol% is preferable, the range of 3-30 mol% is more preferable, and the range of 5-20 mol% is further more preferable.

式（ａ４−４）中、
Ｌ^a7は、酸素原子又は＊−Ｏ−（ＣＨ₂）_k4−ＣＯ−Ｏ−を表し、
ｋ４は１〜７の整数を表す。＊はカルボニル基（−ＣＯ−）との結合手を表す。
Ｒ^a28は、水素原子又はメチル基を表す。
Ｗ¹⁶は、置換基を有していてもよいスルトン環を含む残基を表す。 Furthermore, examples of the acid stable monomer (a4) include an acid stable monomer having a sultone ring represented by the formula (a4-4) (hereinafter sometimes referred to as “acid stable monomer (a4-4)”). Can be mentioned.

In formula (a4-4),
L ^a7 represents an oxygen atom or * —O— (CH ₂ ) _k4 —CO—O—,
k4 represents an integer of 1 to 7. * Represents a bond with a carbonyl group (—CO—).
R ^a28 represents a hydrogen atom or a methyl group.
W ¹⁶ represents a residue containing a sultone ring which may have a substituent.

置換基を有していてもよいスルトン環を含む残基とは、上述の結合手に置き換わった以外の水素原子がさらに置換基で置換されたものであり、該置換基としては、ヒドロキシ基、シアノ基、炭素数１〜６のアルキル基、炭素数１〜６のフッ素化アルキル基、炭素数１〜６のヒドロキシアルキル基、炭素数１〜６のアルコキシ基、炭素数１〜７のアルコキシカルボニル基、炭素数１〜７のアシル基及び炭素数１〜８のアシルオキシ基が挙げられる。 Examples of the sultone ring include those shown below. A typical example of a residue containing a sultone ring is one in which one of the hydrogen atoms in the sultone ring shown below is replaced with a bond.

The residue containing a sultone ring which may have a substituent is a group in which a hydrogen atom other than the above-described bond is further substituted with a substituent, such as a hydroxy group, Cyano group, alkyl group having 1 to 6 carbon atoms, fluorinated alkyl group having 1 to 6 carbon atoms, hydroxyalkyl group having 1 to 6 carbon atoms, alkoxy group having 1 to 6 carbon atoms, alkoxycarbonyl having 1 to 7 carbon atoms Group, an acyl group having 1 to 7 carbon atoms, and an acyloxy group having 1 to 8 carbon atoms.

Examples of the monomer represented by the formula (a4-4) include the following.

  When the resin (A) has a structural unit derived from the acid-stable monomer (a4-4), the content thereof is 2 to 40 mol% with respect to the total structural unit (100 mol%) of the resin (A). The range is preferably 3 to 35 mol%, more preferably 5 to 30 mol%.

In addition, as the acid stable monomer (a4), for example, a monomer having a fluorine atom as shown below [hereinafter referred to as “monomer (a4-5)” may be used. ].

Among the monomers (a4-5), (meth) acrylic acid 5- (3,3,3-trifluoro-2-hydroxy-2- [tri] having a monocyclic or polycyclic alicyclic hydrocarbon group Fluoromethyl] propyl) bicyclo [2.2.1] hept-2-yl, 6- (3,3,3-trifluoro-2-hydroxy-2- [trifluoromethyl] propyl) bicyclo (meth) acrylate [2.2.1] Hept-2-yl and 4,4-bis (trifluoromethyl) -3-oxatricyclo [4.2.1.0 ^2,5 ] nonyl (meth) acrylate are preferred.

  When the resin (A) has a structural unit derived from the monomer (a4-5), the total content thereof is 1 to 20 mol% with respect to all the structural units (100 mol%) of the resin (A). The range is preferable, the range of 2 to 15 mol% is more preferable, and the range of 3 to 10 mol% is more preferable.

  A preferred resin (A) is a copolymer obtained by polymerizing the monomer (a1), the acid stable monomer (a2) and / or the acid stable monomer (a3). In this preferable copolymer, it is preferable to use at least one of the above-mentioned monomer (a1-1) and monomer (a1-2) as monomer (a1), and it is more preferable to use monomer (a1-1). . The acid stable monomer (a2) is preferably an acid stable monomer (a2-1), and the acid stable monomer (a3) is at least one of an acid stable monomer (a3-1) and an acid stable monomer (a3-2). Is preferred.

Resin (A) uses monomer (a1) and, if necessary, an acid-stable monomer selected from the group consisting of acid-stable monomer (a2), acid-stable monomer (a3) and acid-stable monomer (a4), After adjusting the amount of use such that these are suitable for the total structural unit of the resin (A) as described above, it can be produced by a known polymerization method (for example, radical polymerization method).
The weight average molecular weight of the resin (A) is preferably 2,500 or more, more preferably 3,000 or more. The upper limit of the weight average molecular weight is preferably 50,000 or less, and more preferably 30,000 or less. In addition, the weight average molecular weight here is calculated | required as a conversion value of a standard polystyrene reference | standard by gel permeation chromatography analysis, and the detailed analysis conditions of this analysis are explained in full detail in the Example of this application.

<Basic Compound (hereinafter referred to as “Basic Compound (C)”)>
The resist composition of the present invention preferably further contains a basic compound (C). The term “basic compound” as used herein refers to a compound having a property of capturing an acid (hereinafter sometimes referred to as “quencher”), particularly, to capture an acid generated from the acid generator already described. It means a compound having properties. The content of the basic compound (C) may be 0.01 to 1% by mass based on the solid content of the resist composition.

ここで、Ａｒ^c1は、芳香族炭化水素基を表す。
Ｒ^c5及びＲ^c6は、それぞれ独立に、水素原子、アルキル基（好ましくは、炭素数１〜６のアルキル基である。）、脂環式炭化水素基（好ましくは、炭素数５〜１０の脂環式炭化水素基である。）又は芳香族炭化水素基（好ましくは、炭素数６〜１０の芳香族炭化水素基である。）を表す。但し、該アルキル基、該脂環式炭化水素基及び該芳香族炭化水素基にある水素原子は、ヒドロキシ基、アミノ基、又は炭素数１〜６のアルコキシ基で置換されていてもよく、このアミノ基はさらに、炭素数１〜４のアルキル基を有していてもよい。
Ｒ^c7は、アルキル基（好ましくは、炭素数１〜６のアルキル基である。）、炭素数１〜６のアルコキシ基、脂環式炭化水素基（好ましくは、炭素数５〜１０の脂環式炭化水素基であり、さらに好ましくは、炭素数５〜１０のシクロアルキル基である。）、芳香族炭化水素基（好ましくは、炭素数６〜１０の芳香族炭化水素基である。）又はニトロ基を表す。但し、ここでいうアルキル基、アルコキシ基、脂環式炭化水素基及び芳香族炭化水素基にある水素原子も、ヒドロキシ基、アミノ基、又は炭素数１〜６のアルコキシ基で置換されていてもよく、該アミノ基はさらに、炭素数１〜４のアルキル基を有していてもよい。
ｍ３は０〜３の整数を表す。ｍ３が２以上のとき、複数のＲ^c7は、互いに同一でも異なってもよい。 The basic compound (C) is preferably a basic nitrogen-containing organic compound, and examples thereof include amines and ammonium hydroxides. The amine may be an aliphatic amine or an aromatic amine. The aliphatic amine may be any of primary amine, secondary amine and tertiary amine. The aromatic amine may be any of an amino group bonded to an aromatic ring such as aniline and a heteroaromatic amine such as pyridine. Preferred basic compounds (C) include aromatic amines represented by the following formula (C2), and more preferred basic compounds (C) include anilines represented by the following formula (C2-1). .

Here, Ar ^c1 represents an aromatic hydrocarbon group.
R ^c5 and R ^c6 each independently represent a hydrogen atom, an alkyl group (preferably an alkyl group having 1 to 6 carbon atoms), an alicyclic hydrocarbon group (preferably an aliphatic group having 5 to 10 carbon atoms). A cyclic hydrocarbon group) or an aromatic hydrocarbon group (preferably an aromatic hydrocarbon group having 6 to 10 carbon atoms). However, the hydrogen atom in the alkyl group, the alicyclic hydrocarbon group, and the aromatic hydrocarbon group may be substituted with a hydroxy group, an amino group, or an alkoxy group having 1 to 6 carbon atoms. The amino group may further have an alkyl group having 1 to 4 carbon atoms.
R ^c7 is an alkyl group (preferably an alkyl group having 1 to 6 carbon atoms), an alkoxy group having 1 to 6 carbon atoms, or an alicyclic hydrocarbon group (preferably an alicyclic group having 5 to 10 carbon atoms). Or a cycloalkyl group having 5 to 10 carbon atoms), an aromatic hydrocarbon group (preferably an aromatic hydrocarbon group having 6 to 10 carbon atoms) or Represents a nitro group. However, the hydrogen atom in the alkyl group, alkoxy group, alicyclic hydrocarbon group and aromatic hydrocarbon group referred to here may also be substituted with a hydroxy group, an amino group, or an alkoxy group having 1 to 6 carbon atoms. The amino group may further have an alkyl group having 1 to 4 carbon atoms.
m3 represents an integer of 0 to 3. When m3 is 2 or more, the plurality of R ^c7 may be the same as or different from each other.

Examples of the aromatic amine represented by the formula (C2) include 1-naphthylamine and 2-naphthylamine.
Examples of the anilines represented by the formula (C2-1) include aniline, diisopropylaniline, 2-, 3- or 4-methylaniline, 4-nitroaniline, N-methylaniline, N, N-dimethylaniline and diphenylamine. Is mentioned.

式中、
Ｒ^c8と、芳香族炭素と結合するＲ^c20、Ｒ^c21、Ｒ^c23、Ｒ^c24、Ｒ^c25、Ｒ^c26、Ｒ^c27及びＲ^c28は、互いに独立に、Ｒ^c7で説明したいずれかの基を表す。
窒素原子と結合するＲ^c9、Ｒ^c10、Ｒ^c11、Ｒ^c12、Ｒ^c13、Ｒ^c14、Ｒ^c16、Ｒ^c19及びＲ^c22は、互いに同一でも異なってもよく、Ｒ^c5及びＲ^c6で説明したいずれかの基を表す。
ｏ３、ｐ３、ｑ３、ｒ３、ｓ３、ｔ３及びｕ３は、それぞれ独立に０〜３の整数を表す。ｏ３が２以上であるとき、複数のＲ^c20は互いに同一でも異なってもよく、ｐ３が２以上であるとき、複数のＲ^c21は互いに同一でも異なってもよく、ｑ３が２以上であるとき、複数のＲ^c24は互いに同一でも異なってもよく、ｒ３が２以上であるとき、複数のＲ^c25は互いに同一でも異なってもよく、ｓ３が２以上であるとき、複数のＲ^c26は互いに同一でも異なってもよく、ｔ３が２以上であるとき、複数のＲ^c27は互いに同一でも異なってもよく、ｕ３が２以上であるとき、複数のＲ^c28は互いに同一でも異なってもよい。
Ｒ^c15は、アルキル基（好ましくは、炭素数１〜６のアルキル基である。）、脂環式炭化水素基（好ましくは、炭素数３〜６の脂環式炭化水素基である。）又はアルカノイル基（好ましくは、炭素数２〜６のアルカノイル基である。）を表す。
ｎ３は０〜８の整数を表す。ｎ３が２以上のとき、複数のＲ^c15は、互いに同一でも異なってもよい。
Ｌ^c1及びＬ^c2は、それぞれ独立に、２価のアルキレン基（好ましくは、炭素数１〜６のアルキレン基である。）、カルボニル基、−Ｃ（＝ＮＨ）−、−Ｃ（＝ＮＲ^c3）−（但し、Ｒ^c3は、炭素数１〜４のアルキル基を表す。）、チオキシ基、ジスルフィド結合（−Ｓ−Ｓ−）又はこれらの組合せを表す。 In addition, a compound represented by any one of the following formulas (C3) to (C11) (hereinafter referred to as “compound (C3)” to “compound (C11)” depending on the formula number) Can also be used.

Where
And ^{R c8, R c20, R c21} , R c23, R c24, R c25, R c26, R c27 and R ^{c 28} to bind to aromatic carbon, independently of each other, represent any of the groups described in R ^c7 .
R ^c9 , R ^c10 , R ^c11 , R ^c12 , R ^c13 , R ^c14 , R ^c16 , R ^c19 and R ^c22 bonded to the nitrogen atom may be the same as or different from each other, and any of those described for R ^c5 and R ^c6 Represents the group.
o3, p3, q3, r3, s3, t3 and u3 each independently represents an integer of 0 to 3. When o3 is 2 or more, the plurality of R ^c20 may be the same or different from each other. When p3 is 2 or more, the plurality of R ^c21 may be the same or different from each other, and when q3 is 2 or more, multiple R ^c24 may be the same or different from each other, when r3 is 2 or more, plural R ^c25 may be the same or different from each other, when s3 is 2 or more, even the plurality of R ^{c 26} identical to one another When t3 is 2 or more, the plurality of R ^c27 may be the same as or different from each other. When ^u3 is 2 or more, the plurality of R ^c28 may be the same or different from each other.
R ^c15 is an alkyl group (preferably an alkyl group having 1 to 6 carbon atoms), an alicyclic hydrocarbon group (preferably an alicyclic hydrocarbon group having 3 to 6 carbon atoms) or An alkanoyl group (preferably an alkanoyl group having 2 to 6 carbon atoms) is represented.
n3 represents an integer of 0 to 8. When n3 is 2 or more, the plurality of R ^c15 may be the same as or different from each other.
L ^c1 and L ^c2 are each independently a divalent alkylene group (preferably an alkylene group having 1 to 6 carbon atoms), a carbonyl group, —C (═NH) —, —C (═NR ^c3 )-(Wherein R ^c3 represents an alkyl group having 1 to 4 carbon atoms), a thioxy group, a disulfide bond (—S—S—) or a combination thereof.

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

Examples of the compound (C4) include piperazine.
Examples of the compound (C5) include morpholine.
Examples of the compound (C6) include piperidine and hindered amine compounds having a piperidine skeleton described in JP-A No. 11-52575.
Examples of the compound (C7) include 2,2′-methylenebisaniline.
Examples of the compound (C8) include imidazole and 4-methylimidazole.
Examples of the compound (C9) include pyridine and 4-methylpyridine.
Examples of the compound (C10) include 1,2-di (2-pyridyl) ethane, 1,2-di (4-pyridyl) ethane, 1,2-di (2-pyridyl) ethene, and 1,2-di. (4-pyridyl) ethene, 1,3-di (4-pyridyl) propane, 1,2-di (4-pyridyloxy) ethane, di (2-pyridyl) ketone, 4,4′-dipyridyl sulfide, 4, 4'-dipyridyl disulfide, 2,2'-dipyridylamine, 2,2'-dipicolylamine and the like can be mentioned.
Examples of the compound (C11) include bipyridine.

  Examples of ammonium salts include tetramethylammonium hydroxide, tetraisopropylammonium hydroxide, tetrabutylammonium hydroxide, tetrahexylammonium hydroxide, tetraoctylammonium hydroxide, phenyltrimethylammonium hydroxide, and 3- (trifluoromethyl) phenyl. Examples thereof include trimethylammonium hydroxide, tetra-n-butylammonium salicylate and choline.

  Of these, diisopropylaniline is preferable as the basic compound (C) used in the resist composition of the present invention, and 2,6-diisopropylaniline is more preferable.

<Solvent (hereinafter referred to as “solvent (D)”)>
The resist composition of the present invention preferably contains a solvent (D). The solvent (D) is a resist pattern, which will be described later, according to the type and amount of the salt (I) used, the type and amount of the resin (A), and the type and amount of the acid generator (B). In this production, an optimum one can be appropriately selected from the viewpoint that the coatability when the resist composition is coated on the substrate is improved.

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

<Other ingredients>
The resist composition of the present invention comprises a salt (I), a resin (A), a solvent (D), an acid generator (B), and a basic compound (C) other than the salt (I) and the resin (A) as necessary. Ingredients may be included. This component may be referred to as “component (F)”. Examples of the component (F) include additives known in the art, for example, polymer compounds other than the resin (A), sensitizers, dissolution inhibitors, surfactants, stabilizers, and dyes.

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

  The content of the solvent (D) is preferably 90% by mass or more, more preferably 92% by mass or more, still more preferably 94% by mass or more, based on the total mass of the resist composition of the present invention, and 99.9. It is preferably at most mass%, more preferably at most 99 mass%. This resist composition containing the solvent (D) with such a content easily forms a composition layer having a thickness of about 30 to 300 nm in the production of a resist pattern.

It is preferable that content of resin (A) with respect to the resist composition of this invention is 80 to 99 mass% with respect to the total mass of solid content of this resist composition.
In the present specification, “solid content of the composition” means the total of resist composition components excluding the solvent (D) described later. For example, in the resist composition of the present invention in which the content of the solvent (D) is 90% by mass, the solid content of the resist composition corresponds to 10% by mass. The solid content of the composition and the content of each component relative thereto can be measured by known analytical means such as liquid chromatography or gas chromatography, for example.

  The content of the salt (I) in the resist composition of the present invention is preferably 1 part by mass or more, more preferably 3 parts by mass with respect to 100 parts by mass of the resin (A) contained in the resist composition of the present invention. Part or more, preferably 30 parts by mass or less, more preferably 25 parts by mass or less.

  When the acid generator (B) is used in the resist composition of the present invention, a preferable range of the mass contained is selected with respect to the total mass of the resin (A) contained in the resist composition of the present invention. Specifically, the acid generator (B) is preferably 1 part by mass or more and more preferably 3 parts by mass or more with respect to 100 parts by mass of the resin (A). The acid generator (B) is preferably 30 parts by mass or less, more preferably 25 parts by mass or less, relative to 100 parts by mass of the resin (A).

  When the basic compound (C) is used in the resist composition of the present invention, a preferable range of the content thereof is selected with respect to the total mass of the solid content of the resist composition of the present invention. Specifically, the content of the basic compound (C) with respect to the total mass of the solid content is preferably about 0.01 to 1% by mass. As described above, the content of the basic compound (C) is preferably lower than the total content of the salt (I) and the acid generator (B).

  The suitable content of each of the salt (I) and the resin (A) and the acid generator (B) and the basic compound (C) used as necessary is also suitable for preparing the resist composition of the present invention. It can be controlled by the amount of each used. After preparing the resist composition of the present invention, the resist composition of the present invention can be obtained by subjecting it to known analysis means such as gas chromatography and liquid chromatography.

  In addition, when using a component (F) for the resist composition of this invention, suitable content can be adjusted according to the kind of the said component (F).

  Thus, preferable content of each of the salt (I), the resin (A) and the solvent (D), and the acid generator (B), basic compound (C) or component (F) used as necessary. It is preferable to filter using a filter having a pore size of about 0.01 to 0.2 μm.

<Method for producing resist pattern>
Then, the manufacturing method of the resist pattern using the resist composition of this invention is demonstrated.
The method for producing a resist pattern of the present invention comprises:
(1) A step of applying the resist composition of the present invention on a substrate,
(2) The process of drying the composition after application | coating and forming a composition layer,
(3) a step of exposing the composition layer using an exposure machine;
(4) A step of heating the composition layer after exposure,
(5) It includes a step of developing the composition layer after heating.

  The application of the resist composition of the present invention on the substrate in the step (1) can be performed by a coating apparatus widely used for applying a resist material for semiconductor microfabrication, such as a spin coater. Thus, a coating film made of a resist composition is formed on the substrate. The film thickness of the coating film can be adjusted by variously adjusting the conditions (coating conditions) of the coating apparatus, and by applying an appropriate preliminary experiment, the coating film can be applied to have a desired film thickness. You can choose the conditions. As the substrate before applying the resist composition of the present invention, various substrates to be subjected to fine processing can be selected. In addition, before apply | coating the resist composition of this invention, a board | substrate can be wash | cleaned or an antireflection film can also be formed. For example, a commercially available composition for an organic antireflection film can be used for forming the antireflection film.

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

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

  In step (4), the composition layer after exposure is subjected to heat treatment (so-called post-exposure baking). The heat treatment is preferably the heating means using the hot plate shown in the step (2). When performing a heating means using a hot plate in the step (4), the surface temperature of the hot plate is preferably about 50 to 200 ° C, more preferably about 70 to 150 ° C. The deprotection reaction is promoted by the heat treatment.

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

  After development, the manufactured resist pattern is preferably rinsed with ultrapure water or the like. Furthermore, it is preferable to remove moisture remaining on the substrate and the resist pattern.

<Application>
The resist composition of the present invention 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) irradiation, or a resist composition for an EUV exposure machine. It is.

The present invention will be described more specifically with reference to examples. In the examples, “%” and “parts” representing the content or amount used are based on mass unless otherwise specified. The composition ratio of the resin (A) (copolymerization ratio of the structural unit derived from each monomer used for the production of the resin (A) to the resin (A)) is determined by liquid chromatography using the amount of unreacted monomer in the reaction solution after the completion of polymerization. The measurement was performed using a graph, and the amount of monomer used for the polymerization was determined from the obtained results. 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 H _XL -M x 3 + guardcolumn (manufactured by Tosoh Corporation)
Eluent: Tetrahydrofuran Flow rate: 1.0 mL / min
Detector: RI detector Column temperature: 40 ° C
Injection volume: 100 μl
Molecular weight standard: Standard polystyrene (manufactured by Tosoh Corporation)

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

Example 1: Synthesis of a salt represented by the formula (I1)

式（Ｉ１−ａ）で表される化合物２５．００部、式（Ｉ１−ｂ）で表される化合物４１．２９部及びエタノール１２５部からなる溶液に、カリウムｔ−ブトキシド５０．４７部及びテトラキス（トリフェニルホスフィン）パラジウム（０）２．６０部を添加し、これを８０℃で８時間還流した。更に、テトラキス（トリフェニルホスフィン）パラジウム（０）７．８０部を添加し、これを８０℃で６時間還流した。得られた反応物を濃縮した後、酢酸エチル２６２．９８部及びイオン交換水８７．６６部を仕込み、２３℃で３０分間攪拌した。得られたマスを濾過して濾液を回収した。得られた濾液が２層に分離していたので、有機層を分液して取り出し、更に、該有機層にイオン交換水８７．６６部を添加し、水洗した。この操作を３回繰り返した。回収された有機層に、活性炭２．７８部を仕込み、２３℃で３０分間攪拌した後、濾過して濾液を回収した。得られた濾液を濃縮することにより、式（Ｉ１−ｃ）で表される化合物２８．５６部を得た。

In a solution comprising 25.00 parts of the compound represented by formula (I1-a), 41.29 parts of the compound represented by formula (I1-b) and 125 parts of ethanol, 50.47 parts of potassium t-butoxide and tetrakis were added. 2.60 parts of (triphenylphosphine) palladium (0) was added, and this was refluxed at 80 ° C. for 8 hours. Further, 7.80 parts of tetrakis (triphenylphosphine) palladium (0) was added, and this was refluxed at 80 ° C. for 6 hours. After concentrating the obtained reaction product, 262.98 parts of ethyl acetate and 87.66 parts of ion-exchanged water were added and stirred at 23 ° C. for 30 minutes. The resulting mass was filtered to collect the filtrate. Since the obtained filtrate was separated into two layers, the organic layer was separated and taken out. Further, 87.66 parts of ion-exchanged water was added to the organic layer and washed with water. This operation was repeated three times. The recovered organic layer was charged with 2.78 parts of activated carbon, stirred at 23 ° C. for 30 minutes, and then filtered to recover the filtrate. The obtained filtrate was concentrated to obtain 28.56 parts of a compound represented by the formula (I1-c).

式（Ｉ１−ｃ）で表される化合物４．２６部及びアセトン２５部からなる溶液に、過酸化水素２．５０部（純度３１％）を滴下し、これを２３℃で５時間攪拌した。得られた反応物に、酢酸エチル１２５部及びイオン交換水６２．５部を仕込み、２３℃で３０分間攪拌した。得られたマスを濾過して濾液を回収した。得られた濾液が２層に分離していたので、有機層を分液して取り出し、更に、該有機層にイオン交換水４１．６７部を添加し、水洗した。この操作を５回繰り返した。回収された有機層を濃縮した後、ｎ−ヘプタン２１．２５部を添加し攪拌した。上澄み液を除いた後、更に酢酸エチル２０部を加えて２３℃で３０分間攪拌した後、濾過して濾液を回収した。得られた濾液を濃縮することにより、式（Ｉ１−ｄ）で表される化合物１．２４部を得た。

To a solution consisting of 4.26 parts of the compound represented by the formula (I1-c) and 25 parts of acetone, 2.50 parts of hydrogen peroxide (purity 31%) was added dropwise and stirred at 23 ° C. for 5 hours. The obtained reaction product was charged with 125 parts of ethyl acetate and 62.5 parts of ion-exchanged water and stirred at 23 ° C. for 30 minutes. The resulting mass was filtered to collect the filtrate. Since the obtained filtrate was separated into two layers, the organic layer was separated and taken out, and 41.67 parts of ion-exchanged water was further added to the organic layer and washed with water. This operation was repeated 5 times. After the collected organic layer was concentrated, 21.25 parts of n-heptane was added and stirred. After removing the supernatant, 20 parts of ethyl acetate was further added and stirred at 23 ° C. for 30 minutes, followed by filtration to recover the filtrate. The obtained filtrate was concentrated to obtain 1.24 parts of a compound represented by the formula (I1-d).

式（Ｉ１−ｄ）で表される化合物１．２４部及びテトラヒドロフラン１０部からなる溶液に、トリメチルシリルクロライド０．８５部を滴下し、更に、式（Ｉ１−ｅ）で表される化合物２．２２部（純度３２％）を滴下し、これを２３℃で１２時間攪拌した。得られた混合溶液に、式（Ｉ１−ｅ）で表される化合物４．４４部（純度３２％）を滴下し、これを７０℃で３時間還流した。得られた反応物を２３℃まで冷却し、１Ｎ塩酸１０部を滴下し、２３℃で３０分間攪拌した後、２層に分離したので上層を回収した。回収された上層に、ｔｅｒｔ−ブチルメチルエーテル１０部を加えて２３℃で３０分間攪拌した後、ｔｅｒｔ−ブチルメチルエーテル層を取り除いた。回収された層に、クロロホルム３０部を加えて２３℃で３０分間攪拌した後、２層に分離したのでクロロホルム層を回収し、濃縮することにより、式（Ｉ１−ｆ）で表される塩０．５０部を得た。

To a solution consisting of 1.24 parts of the compound represented by the formula (I1-d) and 10 parts of tetrahydrofuran, 0.85 part of trimethylsilyl chloride is added dropwise, and further a compound 2.22 represented by the formula (I1-e). Parts (purity 32%) were added dropwise, and the mixture was stirred at 23 ° C. for 12 hours. To the obtained mixed solution, 4.44 parts (purity 32%) of the compound represented by the formula (I1-e) was dropped, and this was refluxed at 70 ° C. for 3 hours. The obtained reaction product was cooled to 23 ° C., 10 parts of 1N hydrochloric acid was added dropwise, stirred at 23 ° C. for 30 minutes, and then separated into two layers, so that the upper layer was recovered. 10 parts of tert-butyl methyl ether was added to the recovered upper layer and stirred at 23 ° C. for 30 minutes, and then the tert-butyl methyl ether layer was removed. To the recovered layer, 30 parts of chloroform was added and stirred at 23 ° C. for 30 minutes, and then separated into two layers. The chloroform layer was recovered and concentrated to obtain a salt 0 represented by the formula (I1-f). .50 parts were obtained.

特開２００８−２０９９１７号公報に記載された方法によって得られた式（Ｉ１−ｇ）で表される塩０．６１部及びクロロホルム３１．４８部を仕込み、２３℃で３０分間攪拌した後、式（Ｉ１−ｆ）で表される塩０．５０部及びイオン交換水１０部を仕込み、２３℃で３０分間攪拌した。得られた混合溶液に、３５％塩酸０．１７部を添加し、これを２３℃で１２時間攪拌した。得られた反応マスに、２８％アンモニア水０．５部を添加し、２３℃で３０分間攪拌した後、２層に分離したので、クロロホルム層を分液して取り出し、更に、該クロロホルム層にイオン交換水１５．７４部を添加し、水洗した。この操作を５回繰り返した。クロロホルム層を濃縮し、得られた残渣に、ｔｅｒｔ−ブチルメチルエーテル１８．２０部を加えて２３℃で３０分間攪拌した。上澄み液を除いた後、濃縮し、更にアセトニトリル１０部を加えて２３℃で３０分間攪拌した後、濃縮することにより、式（Ｉ１）で表される塩０．１５部を得た。

0.61 part of a salt represented by the formula (I1-g) obtained by the method described in JP-A-2008-209917 and 31.48 parts of chloroform were charged and stirred at 23 ° C. for 30 minutes. 0.50 part of the salt represented by (I1-f) and 10 parts of ion-exchanged water were charged and stirred at 23 ° C. for 30 minutes. To the obtained mixed solution, 0.17 part of 35% hydrochloric acid was added, and this was stirred at 23 ° C. for 12 hours. To the obtained reaction mass, 0.5 part of 28% ammonia water was added, and the mixture was stirred at 23 ° C. for 30 minutes and then separated into two layers. The chloroform layer was separated and removed, and the chloroform layer was further separated. Ion exchange water 15.74 parts was added and washed with water. This operation was repeated 5 times. The chloroform layer was concentrated, 18.20 parts of tert-butyl methyl ether was added to the resulting residue, and the mixture was stirred at 23 ° C. for 30 minutes. After removing the supernatant, the mixture was concentrated, further 10 parts of acetonitrile was added, and the mixture was stirred at 23 ° C. for 30 minutes and then concentrated to obtain 0.15 parts of the salt represented by the formula (I1).

MASS (ESI (+) Spectrum): M ⁺ 264.1
MASS (ESI (−) Spectrum): M ^- 339.1

特開２００８−２０９９１７号公報に記載された方法によって得られた式（Ｉ２−ｇ）で表される塩０．５８部及びクロロホルム３０部を仕込み、２３℃で３０分間攪拌した後、式（Ｉ１−ｆ）で表される塩０．５０部及びイオン交換水１０部を仕込み、２３℃で３０分間攪拌した。得られた混合溶液に、３５％塩酸０．１７部を添加し、これを２３℃で１２時間攪拌した。得られた反応マスに、２８％アンモニア水０．５部を添加し、２３℃で３０分間攪拌した後、２層に分離したので、クロロホルム層を分液して取り出し、更に、該クロロホルム層にイオン交換水１５部を添加し、水洗した。この操作を５回繰り返した。クロロホルム層を濃縮し、得られた残渣に、ｔｅｒｔ−ブチルメチルエーテル２０部を加えて２３℃で３０分間攪拌した。上澄み液を除いた後、濃縮し、更にアセトニトリル１０部を加えて２３℃で３０分間攪拌した後、濃縮することにより、式（Ｉ２）で表される塩０．１４部を得た。 Example 2: Synthesis of a salt represented by the formula (I2)

After adding 0.58 part of the salt represented by the formula (I2-g) obtained by the method described in JP-A-2008-209917 and 30 parts of chloroform and stirring at 23 ° C. for 30 minutes, the formula (I1 0.50 part of the salt represented by -f) and 10 parts of ion-exchanged water were charged and stirred at 23 ° C for 30 minutes. To the obtained mixed solution, 0.17 part of 35% hydrochloric acid was added, and this was stirred at 23 ° C. for 12 hours. To the obtained reaction mass, 0.5 part of 28% ammonia water was added, and the mixture was stirred at 23 ° C. for 30 minutes and then separated into two layers. The chloroform layer was separated and removed, and the chloroform layer was further separated. 15 parts of ion exchange water was added and washed with water. This operation was repeated 5 times. The chloroform layer was concentrated, 20 parts of tert-butyl methyl ether was added to the resulting residue, and the mixture was stirred at 23 ° C. for 30 minutes. After removing the supernatant, the mixture was concentrated, further 10 parts of acetonitrile was added, and the mixture was stirred at 23 ° C. for 30 minutes and then concentrated to obtain 0.14 parts of the salt represented by the formula (I2).

MASS (ESI (+) Spectrum): M ⁺ 264.1
MASS (ESI (-) Spectrum): M ^- 323.0

以下、これらのモノマーを「モノマー（Ａ）」〜「モノマー（Ｅ）」という。
〔樹脂Ａ１の合成〕
モノマー（Ａ）、モノマー（Ｅ）、モノマー（Ｂ）、モノマー（Ｃ）及びモノマー（Ｄ）を、モル比３０：１４：６：２０：３０の割合で仕込んだ。次いで、全モノマーの合計質量に対して、１．５質量倍のジオキサンを加えた。得られた混合物に、開始剤としてアゾビスイソブチロニトリルとアゾビス（２，４−ジメチルバレロニトリル）とを全モノマーの合計モル数に対して、それぞれ、１ｍｏｌ％と３ｍｏｌ％との割合で添加し、これを７５℃で約５時間加熱した。その後、反応液を、大量のメタノールと水との混合溶媒（４：１）に注いで沈殿させる操作を３回行うことにより精製し、重量平均分子量が約７．２×１０^３である共重合体を収率７８％で得た。この共重合体は、次式の構造単位を有するものであり、これを樹脂Ａ１とする。

Synthesis Example 1 (Synthesis of Resin (A))
The monomers used are shown below.

Hereinafter, these monomers are referred to as “monomer (A)” to “monomer (E)”.
[Synthesis of Resin A1]
Monomer (A), monomer (E), monomer (B), monomer (C) and monomer (D) were charged at a molar ratio of 30: 14: 6: 20: 30. Subsequently, 1.5 mass times dioxane was added with respect to the total mass of all the monomers. To the obtained mixture, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) were added as initiators in proportions of 1 mol% and 3 mol%, respectively, with respect to the total number of moles of all monomers. This was heated at 75 ° C. for about 5 hours. Thereafter, the reaction solution is purified by pouring it into a large amount of methanol / water mixed solvent (4: 1) and precipitating three times, and the weight average molecular weight is about 7.2 × 10 ^3. The coalescence was obtained with a yield of 78%. This copolymer has a structural unit of the following formula, and this is designated as resin A1.

[Synthesis of Resin A2]
Monomer (A), monomer (B) and monomer (C) were charged in a molar ratio of 50:25:25, and then 1.5 mass times dioxane was added to the total mass of all monomers. To the obtained mixture, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) were added as initiators in proportions of 1 mol% and 3 mol%, respectively, with respect to the total number of moles of all monomers. This was heated at 80 ° C. for about 8 hours. Thereafter, the reaction solution is purified by pouring it into a large amount of methanol / water mixed solvent (3: 1) and precipitating three times, and the weight average molecular weight is about 9.2 × 10 ^3. The coalescence was obtained in 60% yield. This copolymer has a structural unit of the following formula, and this is designated as resin A2.

Examples 3 to 9 and Comparative Example 1
<Preparation of resist composition>
As shown in Table 4, the following components were mixed, and the obtained mixture was filtered through a fluororesin filter having a pore size of 0.2 μm to prepare a resist composition.

Ｉ２：

Ｂ１：

Ｂ２：

<Resin>
Resin A1 or A2
<Acid generator>
I1:

I2:

B1:

B2:

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

<Manufacture of resist pattern and its evaluation>
An organic antireflective coating composition [ARC-29; manufactured by Nissan Chemical Co., Ltd.] was applied onto a 12-inch silicon wafer and baked at 205 ° C. for 60 seconds to obtain a thickness of 780 mm. An organic antireflection film was formed. Subsequently, the resist composition was spin-coated on the organic antireflection film so that the film thickness after drying (pre-baking) was 85 nm.
After applying the resist composition, the obtained silicon wafer was pre-baked (PB) for 60 seconds at a temperature described in the “PB” column of Table 4 on a direct hot plate. Using the ArF excimer stepper for immersion exposure [XT: 1900 Gi; manufactured by ASML, NA = 1.35, 3/4 Annular XY polarized light] on the wafer on which the resist composition film is thus formed, the exposure amount is stepwise. The line and space pattern was subjected to immersion exposure. Note that ultrapure water was used as the immersion medium.
After the exposure, post-exposure baking (PEB) was performed for 60 seconds on a hot plate at the temperature described in the “PEB” column of Table 4, and then with an aqueous 2.38 mass% tetramethylammonium hydroxide solution for 60 seconds. Paddle development was performed to obtain a resist pattern.

  In each resist film, the exposure amount at which the 50 nm line and space pattern becomes an exposure amount of 1: 1 was defined as the effective sensitivity.

Line edge roughness evaluation (LER): The wall surface of the resist pattern after the lithography process is observed with a scanning electron microscope.
If it is less than 3.5 nm, ◎◎,
Those exceeding 3.5 nm and 4 nm or less
O exceeding 4 nm and 4.5 nm or less
X exceeding 4.5 nm,
Table 5 shows the results of the evaluation.

  If the resist composition containing the salt of the present invention is used as an acid generator, a resist pattern having excellent line edge roughness (LER) can be produced.

Claims (7)

A salt represented by the formula (I).

[In the formula (I),
R ¹ and R ² each independently represents a fluorine atom or a C 1-6 perfluoroalkyl group.
L ¹ represents a single bond or a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, a hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with a fluorine atom, and the divalent The methylene group constituting the saturated hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
Y represents an aliphatic hydrocarbon group having 1 to 18 carbon atoms or an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent, and the aliphatic hydrocarbon group and the alicyclic group. The methylene group constituting the hydrocarbon group may be replaced with an oxygen atom, a sulfonyl group or a carbonyl group.
Z ¹⁺ represents an organic cation having a pyridine ring. ] The salt according to claim 1, wherein Z ¹⁺ is an organic cation represented by the formula (I-Z ¹ -1).

[In the formula (I-Z ¹ -1),
R ³ and R ⁴ each independently represent a hydrogen atom, a halogen atom, a hydroxy group, a cyano group, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or an acyl group having 2 to 5 carbon atoms. To express. ] The salt according to claim 1, wherein Z ¹⁺ is an organic cation represented by the formula (I-Z ¹ -1-1).

The L ¹ is represented by * —CO—O— (CH ₂ ) _n — (* represents a bond with —C (R ¹ ) (R ² ) —, and n represents 0 or 1). The salt according to claim 1, which is a group to be formed.   The acid generator containing the salt in any one of Claims 1-4.   A resin comprising an acid generator according to claim 5 and a resin, wherein the resin has an acid labile group and is insoluble or hardly soluble in an alkaline aqueous solution, and is dissolved in an alkaline aqueous solution by the action of an acid. A resist composition which is a resin to be obtained. (1) The process of apply | coating the resist composition of Claim 6 on a board | substrate,
(2) The process of drying the composition after application | coating and forming a composition layer,
(3) a step of exposing the composition layer using an exposure machine;
(4) A step of heating the composition layer after exposure,
(5) a step of developing the composition layer after heating;
A method for producing a resist pattern including: