JP2012042933A - Resist composition and manufacturing method of resist pattern - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resist composition capable of manufacturing a resist pattern excellent in line edge roughness (LER).SOLUTION: A resist composition includes (A) resin having a structural unit derived from a chemical compound represented by the formula (a) and (B) salt represented by the formula (B1).

Description

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

In recent years, as a semiconductor microfabrication technique, an optical lithography technique using an exposure source of short wavelength light such as an ArF excimer laser (wavelength: 193 nm) has been actively studied, and a resist composition is used for the optical lithography technique. Examples of such a resist composition include triphenylsulfonium perfluorobutanesulfonate, a monomer represented by formula (A), a monomer B represented by formula (B), and a monomer represented by formula (a-1). Resist compositions containing a copolymer are known. (Patent Document 1)

International Publication No. 2007/094474 Pamphlet (Example)

  With the above-described resist compositions known hitherto, the line edge roughness (LER) of the resulting resist pattern has not always been satisfactory.

［式（ａ）中、
Ｒ^１は、水素原子又はメチル基を表す。
環Ｗは、炭素数４〜３６の脂環式炭化水素環を表し、該脂環式炭化水素環に含まれるメチレン基は、酸素原子、硫黄原子、カルボニル基又はスルホニル基に置き換わっていてもよい。
Ｘ^ｘは、単結合又は−Ａ−ＣＯ−Ｏ−を表す。
Ａは炭素数１〜１０の炭化水素基を表す。］

［式（Ｂ１）中、
Ｑ¹及びＱ²は、それぞれ独立に、フッ素原子又は炭素数１〜６のペルフルオロアルキル基を表す。
Ｌ^b1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メチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。
Ｙは、置換基を有していてもよい炭素数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に含まれるメチレン基は、酸素原子、スルホニル基又はカルボニル基に置き換わっていてもよく、該脂環式炭化水素基に含まれるメチレン基は、酸素原子、スルホニル基又はカルボニル基に置き換わっていてもよい。
Ｚ⁺は、有機カチオンを表す。］
〔２〕前記式（ａ）における

［式中、Ｗは上記と同じ意味を表す。＊は結合手を表す。］
で表される基が、式（ａ−１Ａ）で表される基又は式（ａ−２Ａ）で表される基である〔１〕記載のレジスト組成物。

［式（ａ−１Ａ）中、
アダマンタン環に含まれるメチレン基は、酸素原子、硫黄原子、カルボニル基又はスルホニル基に置き換わっていてもよい。アダマンタン環に含まれる水素原子は、ヒドロキシ基、炭素数１〜１２のアルキル基、炭素数１〜１２のアルコキシ基、炭素数３〜１２の脂環式炭化水素基又は炭素数６〜１０の芳香族炭化水素基に置き換わっていてもよい。＊は結合手を表す。］

［式（ａ−２Ａ）中、
シクロヘキサン環に含まれるメチレン基は、酸素原子、硫黄原子、カルボニル基又はスルホニル基に置き換わっていてもよい。シクロヘキサン環に含まれる水素原子は、ヒドロキシ基、炭素数１〜１２のアルキル基、炭素数１〜１２のアルコキシ基、炭素数３〜１２の脂環式炭化水素基又は炭素数６〜１０の芳香族炭化水素基に置き換わっていてもよい。
］
〔３〕前記（Ａ）が、式（ａ）で表される化合物に由来する構造単位に加え、式（ａ１−１）で表される化合物に由来する構造単位及び式（ａ１−２）で表される化合物に由来する構造単位からなる群より選ばれる少なくとも１種を有する樹脂である前記〔１〕又は〔２〕記載のレジスト組成物。

［式（ａ１−１）中、
Ｌ^a1は、酸素原子又は^＊−Ｏ−（ＣＨ₂）_k1−ＣＯ−Ｏ−で表される基を表す。＊はカルボニル基との結合手を表す。
ｋ１は１〜７の整数を表す。
Ｒ^a4は、水素原子又はメチル基を表す。
Ｒ^a6は、炭素数１〜８の脂肪族炭化水素基又は炭素数３〜１０の脂環式炭化水素基を表す。
ｍ１は０〜１４の整数を表す。
式（ａ１−２）中、
Ｌ^a2は、酸素原子又は^＊−Ｏ−（ＣＨ₂）_k２−ＣＯ−Ｏ−で表される基を表す。＊はカルボニル基との結合手である。
ｋ２は１〜７の整数を表す。
Ｒ^a5は、水素原子又はメチル基を表す。
Ｒ^a7は、炭素数１〜８の脂肪族炭化水素基又は炭素数３〜１０の脂環式炭化水素基を表す。
ｎ１は０〜１０の整数を表す。
ｎ１’は０〜３の整数を表す。］
〔４〕前記（Ａ）が、式（ａ）で表される化合物に由来する構造単位に加え、式（ａ３−１）で表される化合物に由来する構造単位、式（ａ３−２）で表される化合物に由来する構造単位及び式（ａ３−３）で表される化合物に由来する構造単位からなる群より選ばれる少なくとも１種を有する樹脂である前記〔１〕〜〔３〕のいずれか記載のレジスト組成物。

［式（ａ３−１）中、
Ｌ^a4は、酸素原子又は^＊−Ｏ−（ＣＨ₂）_k3−ＣＯ−Ｏ−を表す。＊はカルボニル基との結合手を表す。
ｋ３は１〜７の整数を表す。
Ｒ^a18は、水素原子又はメチル基を表す。
Ｒ^a21は、炭素数１〜４の脂肪族炭化水素基を表す。ｐ１は０〜５の整数を表し、ｐ１が２以上のとき、複数のＲ^a21は同一であっても異なってもよい。
式（ａ３−２）中、
Ｌ^a5は、酸素原子又は^＊−Ｏ−（ＣＨ₂）_k3−ＣＯ−Ｏ−を表す。＊はカルボニル基との結合手を表す。
Ｒ^a22は、カルボキシ基、シアノ基又は炭素数１〜４の脂肪族炭化水素基を表す。ｑ１は、０〜３の整数を表し、ｑ１が２以上のとき、複数のＲ^a22は同一であっても異なってもよい。
式（ａ３−３）中、
Ｌ^a6は、酸素原子又は^＊−Ｏ−（ＣＨ₂）_k3−ＣＯ−Ｏ−を表す。＊はカルボニル基との結合手を表す。
Ｒ^a20は、水素原子又はメチル基を表す。
Ｒ^a23は、カルボキシ基、シアノ基又は炭素数１〜４の脂肪族炭化水素基を表す。ｒ１は、０〜３の整数を表し、ｒ１が２以上のとき、複数のＲ^a23は同一であっても異なってもよい。］
〔５〕前記（Ｂ）が、前記式（Ｂ１）のＹが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である塩を含む前記〔１〕〜〔４〕のいずれか記載のレジスト組成物。
〔６〕（１）前記〔１〕〜〔５〕のいずれか記載のレジスト組成物を基板上に塗布する工程、
（２）塗布後の組成物を乾燥させて組成物層を形成する工程、
（３）組成物層を露光する工程、
（４）露光後の組成物層を加熱する工程、
（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 resist composition comprising (A) a resin having a structural unit derived from a compound represented by formula (a) and (B) a salt represented by formula (B1).

[In the formula (a),
R ¹ represents a hydrogen atom or a methyl group.
Ring W represents an alicyclic hydrocarbon ring having 4 to 36 carbon atoms, and the methylene group contained in the alicyclic hydrocarbon ring may be replaced with an oxygen atom, a sulfur atom, a carbonyl group or a sulfonyl group. .
X ^x represents a single bond or -A-CO-O-.
A represents a C1-C10 hydrocarbon group. ]

[In the formula (B1),
Q ¹ and Q ² each independently represents a fluorine atom or a C 1-6 perfluoroalkyl group.
L ^b1 represents a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, and the methylene group contained in 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 which may have a substituent or an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent; The methylene group contained in the aromatic hydrocarbon group may be replaced with an oxygen atom, a sulfonyl group or a carbonyl group, and the methylene group contained in the alicyclic hydrocarbon group is substituted with an oxygen atom, a sulfonyl group or a carbonyl group. It may be.
Z ⁺ represents an organic cation. ]
[2] In the formula (a)

[Wherein W represents the same meaning as described above. * Represents a bond. ]
The resist composition according to [1], wherein the group represented by formula (a) is a group represented by formula (a-1A) or a group represented by formula (a-2A).

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

[In the formula (a-2A),
The methylene group contained in the cyclohexane ring may be replaced with an oxygen atom, a sulfur atom, a carbonyl group or a sulfonyl group. The hydrogen atom contained in the cyclohexane ring is a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms, or an aromatic group having 6 to 10 carbon atoms. It may be replaced by a group hydrocarbon group.
]
[3] In addition to the structural unit derived from the compound represented by formula (a), (A) is a structural unit derived from the compound represented by formula (a1-1) and formula (a1-2). The resist composition according to [1] or [2], wherein the resist composition is a resin having at least one selected from the group consisting of structural units derived from the compound represented.

[In the formula (a1-1),
L ^a1 represents an oxygen atom or a group represented by ^* —O— (CH ₂ ) _k1 —CO—O—. * Represents a bond with a carbonyl group.
k1 represents an integer of 1 to 7.
R ^a4 represents a hydrogen atom or a methyl group.
R ^a6 represents an aliphatic hydrocarbon 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.
In formula (a1-2),
L ^a2 represents an oxygen atom or a group represented by ^* —O— (CH ₂ ) _k2 —CO—O—. * Is a bond to a carbonyl group.
k2 represents an integer of 1 to 7.
R ^a5 represents a hydrogen atom or a methyl group.
R ^a7 represents an aliphatic hydrocarbon group having 1 to 8 carbon atoms or an alicyclic hydrocarbon group having 3 to 10 carbon atoms.
n1 represents an integer of 0 to 10.
n1 ′ represents an integer of 0 to 3. ]
[4] In addition to the structural unit derived from the compound represented by the formula (a), the structural unit derived from the compound represented by the formula (a3-1) (A) is represented by the formula (a3-2). Any of the above [1] to [3], which is a resin having at least one selected from the group consisting of a structural unit derived from a compound represented by the formula and a structural unit derived from a compound represented by formula (a3-3) A resist composition as described above.

[In the formula (a3-1),
L ^a4 represents an oxygen atom or ^* —O— (CH ₂ ) _k3 —CO—O—. * Represents a bond with a carbonyl group.
k3 represents an integer of 1 to 7.
R ^a18 represents a hydrogen atom or a methyl group.
R ^a21 represents an aliphatic hydrocarbon group having 1 to 4 carbon atoms. p1 represents an integer of 0 to 5, and when p1 is 2 or more, a plurality of R ^a21 may be the same or different.
In formula (a3-2),
L ^a5 represents an oxygen atom or ^* —O— (CH ₂ ) _k3 —CO—O—. * Represents a bond with a carbonyl group.
R ^a22 represents a carboxy group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms. q1 represents an integer of 0 to 3, and when q1 is 2 or more, a plurality of ^Ra22s may be the same or different.
In formula (a3-3),
L ^a6 represents an oxygen atom or ^* —O— (CH ₂ ) _k3 —CO—O—. * Represents a bond with a carbonyl group.
R ^a20 represents a hydrogen atom or a methyl group.
R ^a23 represents a carboxy group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms. r1 represents an integer of 0 to 3, and when r1 is 2 or more, a plurality of ^Ra23s may be the same or different. ]
[5] The above (1) to [4], wherein (B) includes a salt in which Y in the formula (B1) is an optionally substituted alicyclic hydrocarbon group having 3 to 18 carbon atoms. ] The resist composition in any one of these.
[6] (1) A step of applying the resist composition according to any one of [1] to [5] on a substrate,
(2) The process of drying the composition after application | coating and forming a composition layer,
(3) a step of exposing the composition layer,
(4) A step of heating the composition layer after exposure,
(5) A method for producing a resist pattern including a step of developing the composition layer after heating.

  According to the resist composition of the present invention, a resist pattern having excellent line edge roughness (LER) can be produced.

<Resist composition>
The resist composition of the present invention (hereinafter sometimes referred to as “the present resist composition”)
(A) A resin having a structural unit derived from the compound represented by formula (a) (hereinafter, sometimes referred to as “resin (A)”) and (B) a salt represented by formula (B1).
Further, the resist composition of the present invention preferably further contains a solvent and / or a basic compound.

式（ａ）中、
Ｒ^１は、水素原子又はメチル基を表す。
環Ｗは、炭素数４〜３６の２価の脂環式炭化水素環を表し、該脂環式炭化水素環に含まれるメチレン基は、酸素原子（−Ｏ−、本明細書では、該酸素原子を「−Ｏ−」で示すことがある。）、硫黄原子（−Ｓ−、本明細書では、該硫黄原子を「−Ｓ−」で示すことがある。）、カルボニル基（−ＣＯ−、本明細書では、該カルボニル基を「−ＣＯ−」で示すことがある。）又はスルホニル基（−ＳＯ_２−、本明細書では、該スルホニル基を「−ＳＯ_２−」で示すことがある。）に置き換わっていてもよい。
Ｘ^ｘは、単結合又は−Ａ−ＣＯ−Ｏ−基を表す。
Ａは炭素数１〜１０の炭化水素基を表す。 <Resin (A)>
The resin (A) has a structural unit derived from the compound represented by the formula (a) (hereinafter sometimes referred to as “compound (a)”).

In formula (a),
R ¹ represents a hydrogen atom or a methyl group.
Ring W represents a divalent alicyclic hydrocarbon ring having 4 to 36 carbon atoms, and the methylene group contained in the alicyclic hydrocarbon ring is an oxygen atom (—O—, in the present specification, the oxygen An atom may be represented by “—O—”), a sulfur atom (—S—, in the present specification, the sulfur atom may be represented by “—S—”), a carbonyl group (—CO—). In the present specification, the carbonyl group may be represented by “—CO—”) or a sulfonyl group (—SO ₂ —, and in the present specification, the sulfonyl group may be represented by “—SO ₂ —”). Yes).
X ^x represents a single bond or a -A-CO-O- group.
A represents a C1-C10 hydrocarbon group.

で示される部分構造は、環Ｗを構成する炭素原子のうちの１つと、Ｘ^ｘ及びブチロラクトンイル基とが結合していることを示す。なお、環Ｗの「脂環式炭化水素環」とは、この環が芳香族性を有さない限り、上述のとおり該環に含まれるメチレン基が、酸素原子、硫黄原子、カルボニル基又はスルホニル基に置き換わっていてもよい。 In formula (a):

Partial structure represented in the with one of one of the carbon atoms constituting the ring W, indicating that the X ^x and butyrolactone-yl groups are attached. The “alicyclic hydrocarbon ring” of ring W means that, as long as the ring does not have aromaticity, the methylene group contained in the ring is an oxygen atom, a sulfur atom, a carbonyl group or a sulfonyl group as described above. It may be replaced with a group.

  W represents an alicyclic hydrocarbon ring having 4 to 36 carbon atoms. The carbon number is more preferably 5 to 18, and further preferably 6 to 12 carbon atoms. Preferred alicyclic hydrocarbon rings include an adamantane ring, a cyclohexane ring and a norbornene ring, and among these, an adamantane ring and a cyclohexane ring are particularly preferred. In addition, carbon number here means carbon number before the methylene group contained in a ring is replaced by the above groups.

（式中、＊は結合手を表す。）
で示される基は、式（ａ−１Ａ）で表される基又は式（ａ−２Ａ）で表される基であると好ましい。

［式（ａ−１Ａ）中、
アダマンタン環に含まれるメチレン基は、酸素原子、硫黄原子、カルボニル基又はスルホニル基に置き換わっていてもよい。アダマンタン環に含まれる水素原子は、ヒドロキシ基、炭素数１〜１２のアルキル基、炭素数１〜１２のアルコキシ基、炭素数３〜１２の脂環式炭化水素基又は炭素数６〜１０の芳香族炭化水素基に置き換わっていてもよい。＊は結合手を表す。］
なお、アダマンタン環に含まれるメチレン基が、酸素原子、硫黄原子、カルボニル基又はスルホニル基に置き換わる場合、置き換えられるメチレン基の個数は最大２個程度である。 A group containing W, ie in formula (a)

(In the formula, * represents a bond.)
Is preferably a group represented by the formula (a-1A) or a group represented by the formula (a-2A).

[In the formula (a-1A),
The methylene group contained in the adamantane ring may be replaced with an oxygen atom, a sulfur atom, a carbonyl group or a sulfonyl group. The hydrogen atom contained in the adamantane ring is a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms, or an aromatic group having 6 to 10 carbon atoms. It may be replaced by a group hydrocarbon group. * Represents a bond. ]
When the methylene group contained in the adamantane ring is replaced with an oxygen atom, a sulfur atom, a carbonyl group or a sulfonyl group, the maximum number of methylene groups to be replaced is about two.

［式（ａ−２Ａ）中、
シクロヘキサン環に含まれるメチレン基は、酸素原子、硫黄原子、カルボニル基又はスルホニル基に置き換わっていてもよい。シクロヘキサン環に含まれる水素原子は、ヒドロキシ基、炭素数１〜１２のアルキル基、炭素数１〜１２のアルコキシ基、炭素数３〜１２の脂環式炭化水素基又は炭素数６〜１０の芳香族炭化水素基に置き換わっていてもよい。
］
なお、シクロヘキサン環に含まれるメチレン基が、酸素原子、硫黄原子、カルボニル基又はスルホニル基に置き換わる場合、置き換えられるメチレン基の個数は最大２個程度である。

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

When the hydrogen atom contained in the adamantane ring of the formula (a-1A) is replaced with a group selected from the group consisting of an alkyl group, an alkoxy group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group, the substitution The number is about 3 at the maximum. When the number of substitutions is 2 or more, the plurality of substituted groups may be the same or different. The “hydrogen atom contained in the adamantane ring” herein refers to a hydrogen atom bonded to a carbon atom that is an atom constituting the ring of the adamantane ring.
Similarly, when the hydrogen atom in the cyclohexane ring of the formula (a-2A) is replaced with a group selected from the group consisting of an alkyl group, an alkoxy group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group, The maximum number of substitutions is about 3. When the number of substitutions is 2 or more, the plurality of substituted groups may be the same or different. Here, the “hydrogen atom in the cyclohexane ring” refers to a hydrogen atom bonded to a carbon atom that is an atom constituting the ring of the cyclohexane ring.

芳香族炭化水素基としては、フェニル基及びナフチル基などが挙げられる。 In the group (substituent) in which the hydrogen atom contained in the adamantane ring of the formula (a-1A) or the cyclohexane ring of the formula (a-2A) may be replaced, the alkyl group includes a methyl group, an ethyl group, a propyl group, Examples thereof include a butyl group and a hexyl group, and these alkyl groups may be linear or branched.
Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a hexyloxy group, and an octyloxy group. These alkoxy groups may be linear or branched.
Examples of the alicyclic hydrocarbon group include the groups shown below.

Examples of the aromatic hydrocarbon group include a phenyl group and a naphthyl group.

［式中、Ｘ^Ｘ１及びＸ^Ｘ２は、それぞれ独立に、単結合又は置換基を有していてもよい炭素数１〜６のアルカンジイル基を表し、ともに単結合であることはない。ただし、式（Ｘ^ｘ−Ａ）〜式（Ｘ^ｘ−Ｃ）で表される基の総炭素数は６〜２０である。］
Ｘ^ｘは単結合であるか、Ａがアルカンジイル基である−Ａ−ＣＯ−Ｏ−で表される基が好ましい。 X ^{x in} formula (a) is a single bond or a group represented by -A-CO-O- (A is as defined above). Examples of the hydrocarbon group for A include an alkanediyl group, a cycloalkanediyl group, and a divalent group obtained by combining these. Examples of the alkanediyl group include methylene group, ethylene group, propane-1,3-diyl group, propane-1,2-diyl group, 2-methylpropane-1,3-diyl group and 2-methylpropane- C1-C10 alkanediyl groups, such as a 1, 2- diyl group, are mentioned. The cycloalkanediyl group may be a polycyclic group such as an adamantanediyl group without being trapped by a monocyclic group such as a cyclohexanediyl group. Examples of the divalent group in which the alkanediyl group and the cycloalkanediyl group are combined include groups represented by the formula (X ^x -A), the formula (X ^x -B), or the formula (X ^x -C). It is done.

[ ^Wherein , X ^X1 and X ^X2 each independently represent a single bond or an alkanediyl group having 1 to 6 carbon atoms which may have a substituent, and are not both single bonds. However, the total number of carbon atoms of the groups represented by the formulas (X ^x -A) to (X ^x -C) is 6 to 20. ]
X ^x is preferably a single bond or a group represented by —A—CO—O— in which A is an alkanediyl group.

Examples of the compound (a) include the following compounds.

  A compound (a) can be manufactured according to the method described in the said patent document 1, for example.

  In the resin (A), the total molar amount of the structural unit derived from the compound (a) with respect to all the structural units (100 mol%) of the resin (A) (the structural unit derived from the compound (a) in the resin (A)) The content is preferably from 1 to 100 mol%, more preferably from 5 to 95 mol%, still more preferably from 5 to 60 mol%, particularly preferably from 5 to 50 mol%. In addition, resin (A) containing the structural unit derived from compound (a) with such content is the molar amount of compound (a) used with respect to the total molar amount of all monomers used when producing resin (A). May be adjusted as appropriate.

  The resin (A) is preferably a resin that is insoluble or hardly soluble in an alkaline aqueous solution and has a property of being alkali-soluble by the action of an acid. Therefore, in addition to the structural unit derived from the compound (a), the resin (A) is further derived from a monomer having an acid labile group (hereinafter sometimes referred to as “acid labile group”). It preferably has a structural unit. Here, “becomes soluble in alkali by the action of an acid” means insoluble or hardly soluble in an aqueous alkali solution before contact with an acid, but becomes soluble in an aqueous alkali solution after contact with an acid. To do. 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 protecting group is eliminated, and the resin (A) is converted into a resin soluble in an alkaline aqueous solution. The hydrophilic group protected by the protecting group corresponds to the acid labile group. Examples of the hydrophilic group include a hydroxy group or a carboxy group, and a carboxy group is more preferable.

  A resin (A) that is 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 is a monomer having an acid labile group (hereinafter referred to as “monomer (a1)”. ) ")) And the compound (a). In the polymerization, only one type of monomer (a1) may be used, or two or more types may be used.

式（１）中、Ｒ^a1、Ｒ^a2及びＲ^a3（以下、場合により「Ｒ^a1〜Ｒ^a3」のように表記する。）は、それぞれ独立に、炭素数１〜８の脂肪族炭化水素基又は炭素数３〜２０の脂環式炭化水素基を表すか、或いは、Ｒ^a1及びＲ^a2が互いに結合して、それらが結合する炭素原子とともに炭素数３〜２０の環を形成する。Ｒ^a1及びＲ^a2が互いに結合して形成される環、該脂肪族炭化水素基又は該脂環式炭化水素基に含まれるメチレン基は、酸素原子、硫黄原子又はカルボニル基に置き換わっていてもよい。＊は結合手を表す。 <Monomer (a1)>
In the case where the hydrophilic group is a carboxy group, the acid labile group is such that the hydrogen atom of the carboxy group is replaced with an organic residue, and the atom of the organic residue bonded to —O— of the carboxy group is a tertiary carbon. Examples include groups that are atoms. 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 the formula (1), R ^a1 , R ^a2 and R ^a3 (hereinafter sometimes referred to as “R ^{a1 to} R ^a3 ”) are each independently an aliphatic hydrocarbon group having 1 to 8 carbon atoms. Alternatively, it represents an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or R ^a1 and R ^a2 are bonded to each other to form a ring having 3 to 20 carbon atoms together with the carbon atom to which they are bonded. The ring formed by combining R ^a1 and R ^{a2, the} methylene group contained in the aliphatic hydrocarbon group or the alicyclic hydrocarbon group may be replaced with an oxygen atom, a sulfur atom or a carbonyl group. . * Represents a bond.

Ｒ^a1〜Ｒ^a3の脂環式炭化水素基は、その炭素数が３〜１６であると好ましい。 Examples of the aliphatic hydrocarbon group for R ^{a1 to} R ^a3 include an alkyl group. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, and an octyl group. These alkyl groups may be linear or branched.
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 of R ^{a1 to} R ^a3 preferably has 3 to 16 carbon atoms.

^Examples of the group represented by —C (R ^a1 ) (R ^a2 ) (R ^a3 ) when R ^a1 and R ^a2 are bonded to each other to form a ring include the following groups. The number of carbon atoms in such a ring is preferably in the range of 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).

式（２）中、Ｒ^b1及びＲ^b2は、それぞれ独立に、水素原子又は炭素数１〜１２の炭化水素基を表し、Ｒ^b3は、炭素数１〜２０の炭化水素基を表すか、或いは、Ｒ^b2及びＲ^b3が互いに結合して、それらが各々結合する炭素原子及び酸素原子とともに炭素数３〜２０の環を形成する。Ｒ^b2及びＲ^b3が互いに結合して形成される環又は該炭化水素基がメチレン基を有する場合、そのメチレン基は、酸素原子、硫黄原子又はカルボニル基に置き換わっていてもよい。＊は結合手を表す。 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. Among such acid labile groups, a preferred acid labile group is, for example, a group represented by the following formula (2) (hereinafter sometimes referred to as “acid labile group (2)”).

In formula (2), R ^b1 and R ^b2 each independently represent 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 the ring formed by bonding R ^b2 and R ^b3 or the hydrocarbon group has a methylene group, the methylene group may be replaced with an oxygen atom, a sulfur atom or a carbonyl group. * Represents a bond.

The hydrocarbon group of R ^{b1 to} R ^b3 may be any of an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group. Here, the aliphatic hydrocarbon group and the alicyclic hydrocarbon group are the same as those described in the case of R ^{a1 to} R ^{a3 in} the formula (1).
Aromatic hydrocarbon groups include phenyl, naphthyl, p-methylphenyl, p-tert-butylphenyl, p-adamantylphenyl, tolyl, xylyl, cumenyl, mesityl, biphenyl, anthryl Groups, phenanthryl groups, 2,6-diethylphenyl groups and aryl groups such as 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) is preferably a monomer having an acid labile group and a carbon-carbon double bond in the molecule, and more preferably a (meth) acrylic monomer having an acid labile group.

  Further preferred monomer (a1) is 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, more preferably an acid labile. It is a (meth) acrylic monomer having a group (1). Here, (meth) acryl represents acryl and / or methacryl.

  Among the (meth) acrylic monomers having the acid labile group (1), the acid labile group (1) is preferably a group having an alicyclic hydrocarbon structure having 5 to 20 carbon atoms. Examples of the group having an alicyclic hydrocarbon structure include the same groups as those described as preferred examples among those described as W in the formula (a). A resin (A) obtained by polymerizing the monomer (a1) having such a sterically bulky alicyclic hydrocarbon structure is produced by using this resist composition containing the resin (A). In this case, the resist pattern can be manufactured with a better resolution.

［式（ａ１−１）中、
Ｌ^a1は、酸素原子又は^＊−Ｏ−（ＣＨ₂）_k1−ＣＯ−Ｏ−で表される基を表す。＊はカルボニル基との結合手を表す。
ｋ１は１〜７の整数を表す。
Ｒ^a4は、水素原子又はメチル基を表す。
Ｒ^a6は、炭素数１〜８の脂肪族炭化水素基又は炭素数３〜１０の脂環式炭化水素基を表す。
ｍ１は０〜１４の整数を表す。
式（ａ１−２）中、
Ｌ^a2は、酸素原子又は^＊−Ｏ−（ＣＨ₂）_k２−ＣＯ−Ｏ−で表される基を表す。＊はカルボニル基との結合手である。
ｋ２は１〜７の整数を表す。
Ｒ^a5は、水素原子又はメチル基を表す。
Ｒ^a7は、炭素数１〜８の脂肪族炭化水素基又は炭素数３〜１０の脂環式炭化水素基を表す。
ｎ１は０〜１０の整数を表す。
ｎ１’は０〜３の整数を表す。］ Among the (meth) acrylic monomers having an acid labile group (1) which is a group having an alicyclic hydrocarbon structure, a monomer represented by the formula (a1-1) (hereinafter referred to as “monomer (a1-1)” And a monomer represented by the formula (a1-2) (hereinafter referred to as “monomer (a1-2)”). The present resist composition containing the resin (A) produced using the monomer (a1-1) and / or the monomer (a1-2) can produce a resist pattern having even better line edge roughness (LER). . In addition, when manufacturing resin (A), these monomers may be used independently and may use 2 or more types.

[In the formula (a1-1),
L ^a1 represents an oxygen atom or a group represented by ^* —O— (CH ₂ ) _k1 —CO—O—. * Represents a bond with a carbonyl group.
k1 represents an integer of 1 to 7.
R ^a4 represents a hydrogen atom or a methyl group.
R ^a6 represents an aliphatic hydrocarbon 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.
In formula (a1-2),
L ^a2 represents an oxygen atom or a group represented by ^* —O— (CH ₂ ) _k2 —CO—O—. * Is a bond to a carbonyl group.
k2 represents an integer of 1 to 7.
R ^a5 represents a hydrogen atom or a methyl group.
R ^a7 represents an aliphatic hydrocarbon group having 1 to 8 carbon atoms or an alicyclic hydrocarbon group having 3 to 10 carbon atoms.
n1 represents an integer of 0 to 10.
n1 ′ represents an integer of 0 to 3. ]

In formula (a1-1), the notation “— (CH ₃ ) _m1 ” means that a hydrogen atom contained in the adamantane ring, that is, a 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 the adamantane ring is m1. Similarly, in the formula (a1-2), the notation “— (CH ₃ ) _m1 ” indicates that the hydrogen atom contained in the cycloalkane ring, that is, the hydrogen atom of the methylene group contained in the cycloalkane ring is the methyl group. It means that the number of methyl groups is n1.

ｍ１は、好ましくは０〜３の整数、より好ましくは０又は１である。
ｎ１は、好ましくは０〜３の整数、より好ましくは０又は１である。
ｎ１’は好ましくは、０又は１である。
＊は、アダマンタン環又はシクロアルカン環との結合手を表す。 L ^a1 and L ^a2 are preferably an oxygen atom or —O— (CH ₂ ) _k1 —CO—O— or —O— (CH ₂ ) _k2 —CO—O in which k1 and k2 are integers of 1 to 4. A group represented by —, more preferably an oxygen atom or a group represented by —O—CH ₂ —CO—O— in which k1 and k2 are 1, more preferably an oxygen atom.
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, an octyl group, and the like. Is mentioned. These alkyl groups may be linear or branched. The aliphatic hydrocarbon group for R ^a6 and R ^a7 is preferably a group having 6 or less carbon atoms. The alicyclic hydrocarbon group of R ^a6 and 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 decahydronaphthyl group, adamantyl group, norbornyl group, methylnorbornyl group, and groups shown below.

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

As a monomer (a1-1), the following are mentioned, for example.

これらの中でも、モノマー（ａ１−１）としては、２−メチルアダマンタン−２−イル（メタ）アクリレート、２−エチルアダマンタン−２−イル（メタ）アクリレート及び２−イソプロピルアダマンタン−２−イル（メタ）アクリレートが好ましく、２−メチルアダマンタン−２−イルメタクリレート、２−エチルアダマンタン−２−イルメタクリレート及び２−イソプロピルアダマンタン−２−イルメタクリレートがより好ましい。

Among these, as the monomer (a1-1), 2-methyladamantan-2-yl (meth) acrylate, 2-ethyladamantan-2-yl (meth) acrylate and 2-isopropyladamantan-2-yl (meth) Acrylates are preferred, with 2-methyladamantan-2-yl methacrylate, 2-ethyladamantan-2-yl methacrylate and 2-isopropyladamantan-2-yl methacrylate being more preferred.

As a monomer (a1-2), the following are mentioned, for example. Among these, as the monomer (a1-2), 1-ethylcyclohexyl (meth) acrylate is preferable, and 1-ethylcyclohexyl methacrylate is more preferable.

  When resin (A) contains the structural unit derived from monomer (a1-1) and / or monomer (a1-2), the sum total of content of the structural unit derived from these monomers is obtained resin (A). The range of 10-95 mol% is preferable with respect to 100 mol%, and the range of 15-90 mol% is more preferable, and the range of 20-85 mol% is further more preferable. In order to make the total content of the structural unit derived from the monomer (a1-1) and / or the structural unit derived from the monomer (a1-2) a desired content, when the resin (A) is produced In addition, the amount of monomer (a1-1) and / or monomer (a1-2) used may be within the above range with respect to the amount of all monomers used.

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の脂肪族炭化水素基、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の脂肪族炭化水素基又は炭素数３〜２０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に含まれる水素原子は、ヒドロキシ基に置換されていてもよく、該脂肪族炭化水素基及び該脂環式炭化水素基に含まれるメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。
Ｒ^a10、Ｒ^a11及びＲ^a12は、それぞれ独立に、炭素数１〜１２の脂肪族炭化水素基又は炭素数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、該脂肪族炭化水素基及び該脂環式炭化水素基に含まれる水素原子は、ヒドロキシ基などで置換されていてもよく、該脂肪族炭化水素基及び該脂環式炭化水素基に含まれるメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。 Examples of the monomer (a1) further include a monomer having a norbornene ring represented by the following formula (a1-3) (hereinafter sometimes referred to as “monomer (a1-3)”).

In formula (a1-3),
R ^a9 represents a hydrogen atom, a C 1-3 aliphatic hydrocarbon group which may have a hydroxy group, a carboxy group, a cyano group or —COOR ^a13 .
R ^a13 represents an aliphatic hydrocarbon group having 1 to 8 carbon atoms or an alicyclic hydrocarbon group having 3 to 20 carbon atoms, and a hydrogen atom contained in the aliphatic hydrocarbon group and the alicyclic hydrocarbon group May be substituted with a hydroxy group, and the methylene group contained in the aliphatic hydrocarbon group and the alicyclic hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
R ^a10 , R ^a11 and R ^a12 each independently represent an aliphatic hydrocarbon 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 Combined with each other to form a ring having 3 to 20 carbon atoms together with the carbon atoms to which these are bonded, the hydrogen atom contained in the aliphatic hydrocarbon group and the alicyclic hydrocarbon group is a hydroxy group, etc. The methylene group contained in the aliphatic hydrocarbon group and the alicyclic hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.

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

Examples of the aliphatic hydrocarbon group which may have a hydroxyl group for R ^a9 include a methyl group, an ethyl group, a propyl group, a hydroxymethyl group and a 2-hydroxyethyl group.
^Examples of the aliphatic hydrocarbon group or alicyclic hydrocarbon group for R ^a13 include a methyl group, an ethyl group, a propyl group, a 2-oxo-oxolan-3-yl group, and a 2-oxo-oxolan-4-yl group. Is mentioned.
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 alicyclic hydrocarbon ring, and specific examples include a cyclohexane ring and an adamantane ring.

  Monomers (a1-3) are, for example, 5-norbornene-2-carboxylic acid-tert-butyl, 5-norbornene-2-carboxylic acid 1-cyclohexyl-1-methylethyl, 5-norbornene-2-carboxylic acid 1-methyl Cyclohexyl, 2-methyl-2-adamantyl 5-norbornene-2-carboxylate, 2-ethyl-2-adamantyl 5-norbornene-2-carboxylate, 1- (4-methylcyclohexyl) 5-norbornene-2-carboxylic acid -1-methylethyl, 1- (4-hydroxycyclohexyl) -1-methylethyl 5-norbornene-2-carboxylate, 1-methyl-1- (4-oxocyclohexyl) ethyl 5-norbornene-2-carboxylate and 1- (1-adamantyl) -1-methylethyl 5-norbornene-2-carboxylate Etc., 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). Therefore, if a resist pattern is produced using this resist composition containing the resin (A) having this structural unit, a resist pattern can be obtained with better resolution. Furthermore, since a rigid norbornane ring can be introduced into the main chain of the resin (A) by using the monomer (a1-3), this resist composition containing the resin (A) has a resist pattern excellent in dry etching resistance. Tends to be obtained.

  As described above, the monomer (a1) with respect to all the structural units (100 mol%) of the resin (A) in that a resist pattern can be produced with good resolution and 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含まれるメチレン基は、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）−で示される基に置き換わっていてもよい。Ｒ^ｃは、水素原子又は炭素数１〜６のアルキル基を表す。
Ｙ^a3は、炭素数１〜１２の脂肪族炭化水素基、炭素数３〜１８の脂環式炭化水素基又は炭素数６〜１８の芳香族炭化水素基であり、該脂肪族炭化水素基、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のアシルオキシ基に置換されていてもよい。］ As the monomer (a1), a monomer represented by the following formula (a1-4) (hereinafter referred to as “monomer (a1-4)”) can 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 or different.
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, The methylene group contained in the saturated hydrocarbon group may be a carbonyl group, oxygen, which 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. It may be replaced by a group represented by an atom, a sulfur atom, a sulfonyl group (—SO ₂ —) or —N (R ^c ) —. R ^c represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
Y ^a3 is an aliphatic hydrocarbon group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms, the aliphatic hydrocarbon group, The hydrogen atom contained in each of the alicyclic hydrocarbon group and the aromatic hydrocarbon group 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, or 2 carbon atoms. It may be substituted with an acyl group having ˜4 or an acyloxy group having 2 to 4 carbon atoms. ]

In formula (a1-4), 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 perfluoro sec-butyl group, and a perfluoro tert-butyl group. , Perfluoropentyl group, perfluorohexyl group, perchloromethyl group, perbromomethyl group, and periodomethyl group.
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.
Hydrocarbon group R ^a34 and R ^a35 represents an aliphatic hydrocarbon group may be either an alicyclic hydrocarbon group and aromatic hydrocarbon group. The aliphatic hydrocarbon group includes those described as the aliphatic hydrocarbon groups of R ^a6 and R ^a7 in formula (a1-1) except that the upper limit of the carbon number is different, and specific examples thereof also include R ^a6 and R a Including those exemplified as the aliphatic hydrocarbon group for ^a7 . As the aliphatic hydrocarbon 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 also includes those described as the R ^a6 and R ^a7 alicyclic hydrocarbon groups of the formula (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) -1-alkyl group, an isobornyl group, and the like are preferable.
The aromatic hydrocarbon group is typically an aryl group, for example, phenyl group, naphthyl group, anthranyl group, p-methylphenyl group, p-tert-butylphenyl group, p-adamantylphenyl group, tolyl group, Xylyl group, cumenyl group, mesityl group, biphenyl group, anthryl group, phenanthryl group, 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl and the like.

When R ^a32 and R ^a33 are alkyl groups, an alkyl group having 1 to 4 carbon atoms is preferable, a methyl group and an ethyl group are more preferable, and a methyl group is particularly preferable.
As the alkoxy group for R ^a33 , a methoxy group and an ethoxy group are more preferable, and a methoxy group is particularly preferable.
Examples of the hydrocarbon group 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, And 2-alkyladamantan-2-yl group, 1- (adamantan-1-yl) alkane-1-yl group, and isobornyl group.

As described above, in X ^a2 and Y ^a3 , the hydrogen atom contained therein may be substituted with a halogen atom or a hydroxy group, but when the hydrogen atom is substituted in this way, the substituent is preferably Is a hydroxy group.

As a monomer (a1-4), the following monomers 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、
Ｒ^３１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。
Ｌ^１〜Ｌ^３は、酸素原子又は硫黄原子又は^＊−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。
Ｚ^１は、単結合又は炭素数１〜６のアルカンジイル基であり、該アルカンジイル基に含まれるメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。
ｓ１及びｓ１’は、それぞれ独立して、０〜４の整数を表す。 The monomer (a1) having an acid labile group (2) is preferably a (meth) acrylic monomer (that is, a monomer having an acrylic group or a methacryl group and an acid labile group (2)). -5) (hereinafter referred to as “monomer (a1-5)”).

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

In formula (a1-5),
R ³¹ is preferably a hydrogen atom, a methyl group or a trifluoromethyl group.
L ¹ is preferably an oxygen atom.
L ² and L ³ are each independently preferably an oxygen atom or a sulfur atom, and it is more preferable that one of L ² and L ³ is an oxygen atom and the other is a sulfur atom.
s1 is preferably 1.
s1 ′ is preferably an integer of 0 to 2.
Z ¹ is preferably a single bond or —CH ₂ —CO—O—.

Specific examples of the monomer (a1-5) are as follows.

  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.

The following monomers can be used as the structural unit (a1) having an acid labile group (1) and a carbon-carbon double bond in the molecule.

  When the resin (A) has a structural unit derived from the above-described monomer, the content thereof is preferably in the range of 10 to 95 mol% with respect to the total structural unit (100 mol%) of the resin (A). The range of 15 to 90 mol% is more preferable, and the range of 20 to 85 mol% is more preferable.

<Acid stable monomer>
As the resin (A), in addition to the compound (a) and the monomer (a1), a copolymer obtained by using a monomer having no acid labile group (hereinafter sometimes referred to as “acid-stable monomer”). Is preferable. Further, it is obtained from the compound (a) and an acid stable monomer as an additive used in the resist composition (that is, a component that is insoluble or hardly soluble in an alkaline aqueous solution and is not a resin that becomes alkali-soluble by the action of an acid). In some cases, a resin having no acid labile group is used.

  When manufacturing resin (A) using an acid stable monomer, it is good to determine the usage-amount of an acid-stable monomer on the basis of the usage-amount of a monomer (a1). The ratio of the amount of the monomer (a1) used and the amount of the acid stable monomer used is represented by [monomer (a1)] / [acid stable monomer], and is 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 as a monomer (a1), it has an adamantyl group with respect to the total amount (100 mol%) of usage-amount of this monomer (a1). 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 this resist composition containing resin (A) to become more favorable.

  As an acid stable monomer, what has a hydroxyl group or a lactone ring in a molecule | numerator is mentioned, for example. A structure derived from an acid-stable monomer having a hydroxy group (hereinafter referred to as “acid-stable monomer (a2)”) and / or an acid-stable monomer having a lactone ring (hereinafter referred to as “acid-stable monomer (a3)”). When the resist (A) having a unit is coated on the substrate with the present resist composition containing the resin (A), the coating film formed on the substrate and / or the composition layer obtained from the coating film is the substrate and The resist pattern can be manufactured with high resolution.

<Acid-stable monomer having a hydroxy group (acid-stable monomer (a2))>
When the acid-stable monomer (a2) is used in the production of the resin (A), a suitable acid-stable monomer (depending on the type of exposure source when producing a resist pattern from the resist composition containing the resin (A), a2). That is, 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, an acid having a phenolic hydroxy group as the acid stable monomer (a2). It is preferable to use a stable monomer (a2-0) [for example, hydroxystyrenes] for the production of the resin (A). 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) for the production of the resin (A). Is preferred. 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は同一であっても異なってもよい］ As the acid stable monomer (a2), 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)”). Can be mentioned. This formula (a2-0) is shown in a form in which the phenolic hydroxy group is not protected with a suitable 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, a plurality of R ^a31 may be the same or different.]

Specific examples of the halogen atom and an alkyl group having carbon atoms of 1 to 6 optionally having a halogen atom of R ^a30 may include the same as those exemplified in the description of R ^a32 of formula (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 particularly preferably a methyl group.
Specific examples of the alkoxy group for R ^a31 can be the same as those exemplified in the description of R ^{a33 in} formula (a1-4). Among these, R ^a31 is preferably an alkoxy group having 1 to 4 carbon atoms, more preferably a methoxy group and an ethoxy group, and further preferably a methoxy group. 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 particularly preferable.
ma is preferably 0, 1 or 2, more preferably 0 or 1, and particularly preferably 0.

  When the resin (A) having a structural unit derived from such an acid stable monomer (a2-0) is produced, the phenolic hydroxy group in the acid stable monomer (a2-0) is protected with an appropriate protecting group. Can be used. Examples of the protecting group include a protecting group that is eliminated with an acid. Since the phenolic hydroxy group protected with a protecting group capable of leaving with an acid can be deprotected by contact with an acid, a structural unit derived from an acid stable monomer (a2-0) can be easily formed. Can do. However, when the resin (A) has a structural unit (a1) containing an acid labile group, an acid-stable monomer (a2-0) in which the phenolic hydroxy group is protected with a protecting group that can be deprotected with a base. ) Is preferably used for the deprotection by contact with a base so that the acid labile group of the structural unit (a1) is not significantly impaired. As the protecting group that can be deprotected with a base, for example, an acetyl group is preferred. Examples of the base include 4-dimethylaminoviridine, triethylamine and the like.

Examples of the acid stable monomer (a2-0) include the following monomers.

  Among the examples of the acid stable monomer (a2-0) described above, 4-hydroxystyrene or 4-hydroxy-α-methylstyrene is particularly preferable. When the resin (A) is produced using 4-hydroxystyrene or 4-hydroxy-α-methylstyrene, it is preferable to use those obtained by protecting the phenolic hydroxy group in these with a protective group.

  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). The range of 10-80 mol% is more preferable, and the range of 15-80 mol% is more preferable.

式（ａ２−１）中、
Ｌ^a3は、酸素原子又は^＊−Ｏ−（ＣＨ₂）_k４−ＣＯ−Ｏ−（ｋ４は１〜７の整数を表す。）を表し、＊はカルボニル基との結合手を表す。
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。 As the acid stable monomer (a2), a monomer represented by the formula (a2-1) (hereinafter sometimes referred to as “acid stable monomer (a2-1)”) may also be used.

In formula (a2-1),
L ^a3 represents an oxygen atom or ^* —O— (CH ₂ ) _k4 —CO—O— (k4 represents an integer of 1 to 7), and * represents a bond with a carbonyl group.
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, k4 There are groups represented there _{-O- (CH 2) k2 -CO-} O- in an integer of from 1 to 4, more preferably Is an oxygen atom or a group represented by —O— (CH ₂ ) _k2 —CO—O—, wherein k4 is 1, more preferably an oxygen atom.
R ^a14 is preferably a methyl group.
R ^a15 is preferably a hydrogen atom.
R ^a16 is preferably a hydrogen atom or a hydroxy group.
o1 is preferably an integer of 0 to 3, more preferably 0 or 1.

Examples of the acid stable monomer (a2-1) include the following. Among these, 3-hydroxyadamantan-1-yl (meth) acrylate, 3,5-dihydroxyadamantan-1-yl (meth) acrylate and (meth) acrylic acid 1- (3,5-dihydroxyadamantan-1-yl Oxycarbonyl) methyl is preferred, 3-hydroxyadamantan-1-yl (meth) acrylate and 3,5-dihydroxyadamantan-1-yl (meth) acrylate are more preferred, 3-hydroxyadamantan-1-yl methacrylate and 3, More preferred is 5-dihydroxyadamantan-1-yl methacrylate.

  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 5-35 mol% is more preferable, and the range of 5-30 mol% is more preferable.

<Acid Stabilizing Monomer Containing Lactone Ring (Acid Stabilizing Monomer (a3))>
The lactone ring possessed by the acid stable monomer (a3) may be monocyclic such as β-propiolactone ring, γ-butyrolactone ring and δ-valerolactone ring, and the monocyclic lactone ring and other rings The condensed ring may be used. Among these lactone rings, a γ-butyrolactone ring and a condensed ring of a γ-butyrolactone ring and another ring are preferable.

式（ａ３−１）中、
Ｌ^a4は、酸素原子又は^＊−Ｏ−（ＣＨ₂）_k3−ＣＯ−Ｏ−（ｋ３は１〜７の整数を表す。）を表す。＊はカルボニル基との結合手を表す。
Ｒ^a18は、水素原子又はメチル基を表す。
Ｒ^a21は、炭素数１〜４の脂肪族炭化水素基を表す。ｐ１は０〜５の整数を表し、ｐ１が２以上のとき、複数のＲ^a21は同一であっても異なってもよい。
式（ａ３−２）中、
Ｌ^a5は、酸素原子又は^＊−Ｏ−（ＣＨ₂）_k3−ＣＯ−Ｏ−（ｋ３は前記と同義である。
）を表す。＊はカルボニル基との結合手を表す。
Ｒ^a22は、カルボキシ基、シアノ基又は炭素数１〜４の脂肪族炭化水素基を表す。ｑ１は、０〜３の整数を表し、ｑ１が２以上のとき、複数のＲ^a22は同一であっても異なってもよい。
式（ａ３−３）中、
Ｌ^a6は、酸素原子又は^＊−Ｏ−（ＣＨ₂）_k3−ＣＯ−Ｏ−（ｋ３は前記と同義である。
）を表す。＊はカルボニル基との結合手を表す。
Ｒ^a20は、水素原子又はメチル基を表す。
Ｒ^a23は、カルボキシ基、シアノ基又は炭素数１〜４の脂肪族炭化水素基を表す。ｒ１は、０〜３の整数を表し、ｒ１が２以上のとき、複数のＲ^a23は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) is referred to as “acid stable monomer (a3-1)”, and the acid stable monomer represented by the formula (a3-2) ( a3) is referred to as “acid-stable monomer (a3-2)”, and acid-stable monomer (a3) represented by formula (a3-3) is referred to as “acid-stable monomer (a3-3)”. Resin (A) having a structural unit derived from acid stable monomer (a3) selected from the group consisting of acid stable monomer (a3-1), acid stable monomer (a3-2) and acid stable monomer (a3-3) is The present resist composition is capable of producing a resist pattern having an even better LER.

In formula (a3-1),
L ^a4 represents an oxygen atom or ^* —O— (CH ₂ ) _k3 —CO—O— (k3 represents an integer of 1 to 7). * Represents a bond with a carbonyl group.
R ^a18 represents a hydrogen atom or a methyl group.
R ^a21 represents an aliphatic hydrocarbon group having 1 to 4 carbon atoms. p1 represents an integer of 0 to 5, and when p1 is 2 or more, a plurality of R ^a21 may be the same or different.
In formula (a3-2),
L ^a5 is an oxygen atom or ^* —O— (CH ₂ ) _k3 —CO—O— (k3 is as defined above).
). * Represents a bond with a carbonyl group.
R ^a22 represents a carboxy group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms. q1 represents an integer of 0 to 3, and when q1 is 2 or more, a plurality of ^Ra22s may be the same or different.
In formula (a3-3),
L ^a6 is an oxygen atom or ^* —O— (CH ₂ ) _k3 —CO—O— (k3 is as defined above).
). * Represents a bond with a carbonyl group.
R ^a20 represents a hydrogen atom or a methyl group.
R ^a23 represents a carboxy group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms. r1 represents an integer of 0 to 3, and when r1 is 2 or more, a plurality of ^Ra23s may be the same or different.

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

Examples of the acid stable monomer (a3-1) having a γ-butyrolactone ring include the following.

Examples of the acid stable monomer (a3-2) having a condensed ring of γ-butyrolactone ring and norbornane ring include the following.

Examples of the acid stable monomer (a3-3) having a condensed ring of a γ-butyrolactone ring and a cyclohexane ring include the following.

Among acid-stable monomers (a3) having a lactone ring, (meth) acrylic acid (5-oxo-4-oxatricyclo [4.2.1.0 ^3,7 ] nonan-2-yl, (meth) acrylic Acid tetrahydro-2-oxo-3-furyl, 2- (5-oxo-4-oxatricyclo [4.2.1.0 ^3,7 ] nonan-2-yloxy) -2-oxoethyl (meth) acrylate Such methacrylate esters are more preferred.

  The resin (A) is composed of a structural unit derived from an acid stable monomer (a3-1), a structural unit derived from an acid stable monomer (a3-2), and a structural unit derived from an acid stable monomer (a3-3). In the case of having at least one structural unit selected from [acid-stable monomer (a3)], the total content thereof is 5 with respect to the total structural units (100 mol%) of the resin (A). It is chosen from the range of -50 mol%, the range of 10-40 mol% is preferable, and the range of 15-40 mol% is more preferable. By carrying out like this, this resist composition containing this resin (A) can manufacture the resist pattern which has much more superior LER.

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の脂肪族炭化水素基、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の脂肪族炭化水素基又は炭素数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に含まれるメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。但し−ＣＯＯＲ^a27が酸不安定基となるものは除く（即ちＲ^a27は、第三級炭素原子が−Ｏ−と結合するものを含まない）。 <Acid-stable monomer (a4)>
Furthermore, as acid stable monomer (a4) which is another acid stable monomer, maleic anhydride represented by formula (a4-1), itaconic anhydride represented by formula (a4-2), and formula (a4) -3) and an acid stable monomer having a norbornene ring (hereinafter referred to as “acid stable monomer (a4-3)”).

In formula (a4-3),
R ^a25 and R ^a26 each independently represent a hydrogen atom, a C 1-3 aliphatic hydrocarbon group ^optionally having a hydroxy group, a cyano group, a carboxy group, or —COOR ^a27 , or R a ^a25 and R ^a26 combine with each other to form —CO—O—CO—.
R ^a27 represents an aliphatic hydrocarbon group having 1 to 18 carbon atoms or an alicyclic hydrocarbon group having 3 to 18 carbon atoms, and a methylene group contained in the aliphatic hydrocarbon group and the alicyclic hydrocarbon group. May be replaced by an oxygen atom or a carbonyl group. However, those in which —COOR ^a27 is an acid labile group are excluded (that is, R ^a27 does not include those in which a tertiary carbon atom is bonded to —O—).

In R ^a25 and R ^a26 in formula (a4-3), ^examples of the aliphatic hydrocarbon group which may have a hydroxy group include a methyl group, an ethyl group, a propyl group, a hydroxymethyl group, and 2-hydroxyethyl. Group and the like.
The aliphatic hydrocarbon group for R ^a27 is preferably a group having 1 to 8 carbon atoms, more preferably 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 2-oxo-oxolan-3-yl group, and a 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 an acid stable monomer (a4- 3) When having at least one structural unit selected from the group consisting of structural units derived from [a structural unit derived from acid-stable monomer (a4)], the total content is all structural units of resin (A) The range of 2 to 40 mol% is preferable with respect to (100 mol%), the range of 3 to 30 mol% is more preferable, and the range of 5 to 20 mol% is more preferable.

式（ａ４−４）中、
Ｌ^a7は、酸素原子又は^＊−Ｔ−（ＣＨ₂）_k2−ＣＯ−Ｏ−（ｋ２は１〜７の整数を表す。Ｔは酸素原子又はＮＨである。）を表し、＊はカルボニル基との結合手を表す。
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, as the acid stable monomer (a4), for example, an acid stable monomer having a sultone ring represented by the formula (a4-4) in the molecule (hereinafter referred to as “acid stable monomer (a4-4)” in some cases.
) And the like.

In formula (a4-4),
L ^a7 represents an oxygen atom or ^* —T— (CH ₂ ) _k2 —CO—O— (k2 represents an integer of 1 to 7. T is an oxygen atom or NH), and * represents a carbonyl group Represents the bond hand.
R ^a28 represents a hydrogen atom or a methyl group.
W ¹⁶ represents a residue containing a sultone ring which may have a substituent.

スルトン環を含む残基のうち置換基を有するものとは、上述のＬ^a7との結合手に置き換わった水素原子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. Representative examples of residues containing sultone ring, one of the hydrogen atoms in the sultone ring shown below, but replacing a bond to L ^a7.

And those having a substituent of the residues containing the sultone ring, which hydrogen atoms other than hydrogen atoms replaced with a bond to the above-mentioned L ^a7 is further substituted with a substituent, as the substituent , 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, 1 to 1 carbon atom 7 alkoxycarbonyl group, a C1-C7 acyl group, and a C1-C8 acyloxy group are mentioned.

Specific examples of the acid stable monomer (a4-4) are shown below.

  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%.

Examples of the acid stable monomer (a4) include a monomer having a fluorine atom as shown below [hereinafter referred to as “acid stable monomer (a4-5)” in some cases. ] Can also be used.

Among such acid stable monomers (a4-5), (meth) acrylic acid 5- (3,3,3-trifluoro-2-hydroxy) having a monocyclic or polycyclic alicyclic hydrocarbon group 2- [trifluoromethyl] propyl) bicyclo [2.2.1] hept-2-yl, (meth) acrylic acid 6- (3,3,3-trifluoro-2-hydroxy-2- [trifluoro Methyl] propyl) bicyclo [2.2.1] hept-2-yl, 4,4-bis (trifluoromethyl) -3-oxatricyclo [4.2.1.0 ^2,5 (meth) acrylic acid Nonyl is preferred.

  When the resin (A) has a structural unit derived from the acid-stable monomer (a4-5), the total content is 1 to 20 mol with respect to the total structural unit (100 mol%) of the resin (A). %, Preferably in the range of 2-15 mol%, more preferably in the range of 3-10 mol%.

［式（３）中、Ｒ^１０は、炭素数１〜６のフッ化アルキル基を表す。］ <Other Acid Stable Monomers Having a Group Represented by Formula (3) (hereinafter, referred to as “acid stable monomer (a5)”)>
The acid stable monomer (a5) has a group represented by the following formula (3).

Wherein ^{(3), R 10} represents a fluoroalkyl group having 1 to 6 carbon atoms. ]

The fluorinated alkyl group for R ¹⁰ means an alkyl group having a fluorine atom. Examples of the fluorinated alkyl group include difluoromethyl group, trifluoromethyl group, 1,1-difluoroethyl group, 2,2-difluoroethyl group, 2,2,2-trifluoroethyl group, perfluoroethyl group, 1, 1,2,2-tetrafluoropropyl group, 1,1,2,2,3,3-hexafluoropropyl group, perfluoroethylmethyl group, 1- (trifluoromethyl) -1,2,2,2-tetra Fluoroethyl group, perfluoropropyl group, 1,1,2,2-tetrafluorobutyl group, 1,1,2,2,3,3-hexafluorobutyl group, 1,1,2,2,3,3 4,4-octafluorobutyl group, perfluorobutyl group, 1,1-bis (trifluoro) methyl-2,2,2-trifluoroethyl group, 2- (perfluoropropyl) ethyl group 1,1,2,2,3,3,4,4-octafluoropentyl group, perfluoropentyl group, 1,1,2,2,3,3,4,4,5,5-decafluoropentyl group, 1,1-bis (trifluoromethyl) -2,2,3,3,3-pentafluoropropyl group, perfluoropentyl group, 2- (perfluorobutyl) ethyl group, 1,1,2,2,3 3,4,4,5,5-decafluorohexyl group, 1,1,2,2,3,3,4,4,5,5,6,6-dodecafluorohexyl group, perfluoropentylmethyl group and perfluoro A hexyl group is mentioned.

The fluorinated alkyl group of R ¹⁰ preferably has 1 to 4 carbon atoms, more preferably a trifluoromethyl group, a perfluoroethyl group, and a perfluoropropyl group, and particularly preferably a trifluoromethyl group.

As an acid stable monomer (a5), what is represented by the following is mentioned, for example.

  When the resin (A) has a structural unit derived from a structural unit derived from the acid-stable monomer (a5), the content thereof is 5 to 5 with respect to the total structural unit (100 mol%) of the resin (A). The range of 90 mol% is preferable, the range of 10 to 80 mol% is more preferable, and the range of 20 to 70 mol% is more preferable.

［式（４）中、Ｒ^１１は置換基を有してもよい炭素数６〜１２の芳香族炭化水素基を表す。
Ｒ^１２は、置換基を有してもよい炭素数１〜１２の炭化水素基を表し、該炭化水素基は、ヘテロ原子を含んでいてもよい。
Ａ^２は、単結合、−（ＣＨ_２）_ｍ−ＳＯ_２−Ｏ−＊又は−（ＣＨ_２）_ｍ−ＣＯ−Ｏ−＊を表し、該〔−（ＣＨ_２）_ｍ−〕に含まれるメチレン基は、酸素原子、カルボニル基又はスルホニル基に置き換わっていてもよく、該〔−（ＣＨ_２）_ｍ−〕に含まれる水素原子は、フッ素原子に置き換わっていてもよい。
ｍは、１〜１２の整数を表す。］ <Acid Stable Monomer Having a Group Represented by Formula (4) (hereinafter, referred to as “acid stable monomer (a6)”)>
The acid stable monomer (a6) has a group represented by the following formula (4).

[In formula (4), R ¹¹ represents an aromatic hydrocarbon group having 6 to 12 carbon atoms which may have a substituent.
R ¹² represents an optionally substituted hydrocarbon group having 1 to 12 carbon atoms, and the hydrocarbon group may contain a hetero atom.
A ² represents a single bond, — (CH ₂ ) _m —SO ₂ —O— * or — (CH ₂ ) _m —CO—O— *, and methylene contained in [— (CH ₂ ) _m —] The group may be replaced with an oxygen atom, a carbonyl group or a sulfonyl group, and the hydrogen atom contained in [— (CH ₂ ) _m —] may be replaced with a fluorine atom.
m represents an integer of 1 to 12. ]

Examples of the aromatic hydrocarbon group having 6 to 12 carbon atoms in R ¹¹ include a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, and an anthryl group. When these aromatic hydrocarbon groups have a substituent, the substituent is an alkyl group having 1 to 4 carbon atoms, a halogen atom, a phenyl group, a nitro group, a cyano group, a hydroxy group, a phenyloxy group, and tert-butylphenyl. Group. Examples of the alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, a propyl group, and a butyl group, and examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

Examples of R ¹¹ include the following groups. Note that * is a bond with a carbon atom.

Examples of the hydrocarbon group having 1 to 12 carbon atoms in R ^12, an aliphatic hydrocarbon group may be either an alicyclic hydrocarbon group and aromatic hydrocarbon group.
Examples of the aliphatic hydrocarbon group include methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n -Linear alkyl groups such as decyl group, n-undecyl group and dodecyl group, isopropyl group, sec-butyl group, tert-butyl group, methylpentyl group, ethylpentyl group, methylhexyl group, ethylhexyl group, propylhexyl group and A branched alkyl group such as a tert-octyl group may be used, but an isopropyl group, a sec-butyl group, a tert-butyl group and an ethylhexyl group are preferred.

Examples of the alicyclic hydrocarbon group include the following groups.

When R ¹² is an aliphatic hydrocarbon group or an alicyclic hydrocarbon group, these aliphatic hydrocarbon group or alicyclic hydrocarbon group may contain a hetero atom. The hetero atom is a halogen atom, a sulfur atom, an oxygen atom, a nitrogen atom or the like [a sulfonyl group or a carbonyl group may be included as a linking group].

Examples of R ¹² containing such a hetero atom include the groups shown below.

When R ¹² is an aromatic hydrocarbon group, specific examples thereof are the same as those described in the case of R ¹¹ .

A ² includes the following groups.

［式（ａ６−１）中、Ｒ^１３は、水素原子又はメチル基を表す。
Ｒ^１１、Ｒ^１２及びＡ^２は、上記と同じ意味を表す。］ As the acid stable monomer (a6), for example, a monomer represented by the formula (a6-1) is preferable.

[In formula (a6-1), R ¹³ represents a hydrogen atom or a methyl group.
R ¹¹ , R ¹² and A ² represent the same meaning as described above. ]

Specific examples of the monomer represented by the formula (a6-1) include compounds represented by the following.

  When the resin (A) has a structural unit derived from the monomer (a6), the content thereof is preferably in the range of 5 to 90 mol% with respect to the total structural unit (100 mol%) of the resin (A). The range of 10-80 mol% is more preferable, and the range of 20-70 mol% is more preferable.

A preferred resin (A) is a copolymer obtained by polymerizing the compound (a), 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.
In obtaining this resist composition capable of producing a resist pattern having an even better LER, compound (a), monomer (a1-1) and / or monomer (a1-2), and acid-stable monomer (a3- 1) A copolymer obtained by polymerizing an acid stable monomer (a3) selected from the group consisting of an acid stable monomer (a3-2) and an acid stable monomer (a3-3) is used as the resin (A). Is more preferable.

Resin (A) is an acid selected from the group consisting of compound (a), monomer (a1), and optionally acid-stable monomer (a2), acid-stable monomer (a3) and acid-stable monomer (a4). After using the stable monomer and adjusting the amount of use so that the content thereof is suitable for the total structural unit of the resin (A) as described above, it is produced by a known polymerization method (for example, radical polymerization method). be able to.
The weight average molecular weight of the resin (A) is preferably 2,500 or more, more preferably 3,000 or more. Further, 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.

式（Ｂ１）中、
Ｑ¹及びＱ²は、それぞれ独立に、フッ素原子又は炭素数１〜６のペルフルオロアルキル基を表す。
Ｌ^b1は、単結合又は炭素数１〜１７の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれるメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。
Ｙは、置換基を有していてもよい炭素数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に含まれるメチレン基は、酸素原子、スルホニル基又はカルボニル基に置き換わっていてもよい。
Ｚ⁺は、有機カチオンである。 <Acid generator (B)>
The salt represented by the formula (B1) (hereinafter sometimes referred to as “acid generator (B)”) functions as an acid generator in the present resist composition. In the following description, among the acid generators (B), Z ⁺ having a positive charge is referred to as an “organic cation”, and a negative charge obtained by removing the organic cation is referred to as a “sulfonate anion”. There is.

In formula (B1),
Q ¹ and Q ² each independently represents a fluorine atom or a C 1-6 perfluoroalkyl group.
L ^b1 represents a single bond or a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, and the methylene group contained in 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 which may have a substituent or an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent; The methylene group contained in the aromatic hydrocarbon group and the alicyclic hydrocarbon group may be replaced with an oxygen atom, a sulfonyl group or a carbonyl group.
Z ⁺ is an organic cation.

Perfluoroalkyl groups for Q ¹ and Q ² are, for example, trifluoromethyl group, perfluoroethyl group, perfluoropropyl group, perfluoroisopropyl group, perfluorobutyl group, perfluorosec-butyl group, perfluorotert-butyl group, perfluoropentyl group and perfluoro group. A hexyl group etc. are mentioned.
In the present resist composition, Q ¹ and Q ² are each independently preferably an acid generator (B) in which a trifluoromethyl group or a fluorine atom is used, and an acid generator in which both Q ¹ and Q ² are fluorine atoms. (B) is more preferable. The present resist composition containing the acid generator (B) in which both Q ¹ and Q ² are fluorine atoms and the resin (A) can produce a resist pattern with an even better LER.

Examples of the divalent saturated hydrocarbon group for L ^b1 include a linear alkanediyl group, a branched alkanediyl group, and a monocyclic or polycyclic divalent alicyclic hydrocarbon group. 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, propane-1,1-diyl and propane-2,2-diyl;
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 alkanediyl groups containing the side chains 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;
A single cycloalkanediyl group such as a cyclobutane-1,3-diyl group, a 1,3-cyclopentane-1,3-diyl group, a cyclohexane-1,4-diyl group, and a cyclooctane-1,5-diyl group; A cyclic divalent alicyclic hydrocarbon group;
Polycyclic divalent alicyclic rings such as norbornane-1,4-diyl group, norbornane-2,5-diyl group, 1,5-adamantane-1,5-diyl group and adamantane-2,6-diyl group A formula hydrocarbon group and the like.

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し、Ｌ^b4は、炭素数１〜１３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及びＬ^b7は、それぞれ独立に、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。
本レジスト組成物には、これらの中でも、式（ｂ１−１）で表される基をＬ^b1として有する酸発生剤（Ｂ）が好ましく、Ｌ^b2が単結合又はメチレン基である式（ｂ１−１）で表される基をＬ^b1として有する酸発生剤（Ｂ）がより好ましい。 Examples of the methylene group contained in the divalent saturated hydrocarbon group in L ^b1 replaced with an oxygen atom or a carbonyl group include the following formulas (b1-1), (b1-2), and ( b1-3), formula (b1-4), formula (b1-5), and formula (b1-6) [hereinafter expressed as “formula (b1-1) to formula (b1-6)”. ] The group shown by either of these is mentioned. L ^b1 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 formula (b1-2). is there. Incidentally, the formula (b1-1) ~ formula (b1-6) has its left and right are described in accordance with the formula (B1), the left bond ^{is, C (Q 1) (Q} 2) coupled with and The right hand is connected to Y. The same applies to specific examples of groups represented by formula (b1-1) to formula (b1-6) described later.

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, and L ^b4 represents a 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 and L ^b7 each independently represent 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, the acid generator (B) having a group represented by the formula (b1-1) as L ^b1 is preferable for the resist composition, and the formula (b1−) wherein L ^b2 is a single bond or a methylene group. The acid generator (B) having the group represented by 1) as L ^b1 is more preferable.

Here, specific examples of the groups represented by formula (b1-1) to formula (b1-6) are given. Note that * represents a bond.
Examples of the group represented by the formula (b1-1) include the following.

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

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

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

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

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

The divalent saturated hydrocarbon group for L ^b1 may have a substituent. Examples of the substituent include a halogen atom, a hydroxy group, a carboxy group, an aromatic hydrocarbon group having 6 to 18 carbon atoms, an aralkyl group having 7 to 21 carbon atoms, an acyl group having 2 to 4 carbon atoms, and a glycidyloxy group. Can be mentioned. Examples of the aromatic hydrocarbon group include a phenyl group, a tosyl group, and a naphthyl group. Examples of the aralkyl group include benzyl group, phenethyl group, phenylpropyl group, trityl group, naphthylmethyl group, and naphthylethyl group. Examples of the acyl group include an acetyl group and a propionyl group.

Y in Formula (B1) is an optionally substituted aliphatic hydrocarbon group having 1 to 18 carbon atoms or an optionally substituted alicyclic hydrocarbon group having 3 to 18 carbon atoms. Represents.
As the aliphatic hydrocarbon group for Y, an alkyl group is preferable, and an alkyl group having 1 to 6 carbon atoms is more preferable. The alkyl group may be linear or branched. Further, the alicyclic hydrocarbon group of Y is more preferably an alicyclic hydrocarbon group having 3 to 12 carbon atoms. The alicyclic hydrocarbon group may be monocyclic or polycyclic.
As described above, the aliphatic hydrocarbon group and the alicyclic hydrocarbon group optionally have a substituent. Here, the “aliphatic hydrocarbon group having a substituent” means a group in which a hydrogen atom contained in the aliphatic hydrocarbon group is substituted with a substituent. On the other hand, the “alicyclic hydrocarbon group having a substituent” means a group in which a hydrogen atom contained in the alicyclic hydrocarbon group is substituted with a substituent. Examples of the substituent here 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 ^b1 (wherein R ^b1 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 hydrogen atom contained in the alicyclic hydrocarbon group, the aromatic hydrocarbon group, and the aralkyl group may be substituted with, for example, an alkyl group, a halogen atom, or a hydroxy group.
The hydrogen atom contained in the aliphatic hydrocarbon group of Y may be substituted with an alicyclic hydrocarbon group having 3 to 16 carbon atoms, and the hydrogen atom contained in the alicyclic hydrocarbon group of Y is carbon It may be substituted with an aliphatic hydrocarbon group of formula 1-18.
The methylene group contained in the aliphatic hydrocarbon group or alicyclic hydrocarbon group of Y may be replaced with an oxygen atom, a sulfonyl group or a carbonyl group.
Examples of the group in which the methylene group contained in the alicyclic hydrocarbon group is replaced by an oxygen atom, a sulfonyl group or a carbonyl group include, for example, a cyclic ether group (one or two of the methylene groups contained in the alicyclic hydrocarbon group). One is replaced by an oxygen atom), a cyclic ketone group (a group in which one or two of the methylene groups contained in the alicyclic hydrocarbon group are replaced by a carbonyl group), a sultone ring group (included in the alicyclic hydrocarbon group) Of two methylene groups adjacent to each other are groups in which oxygen atoms and sulfonyl groups are replaced, respectively, and lactone ring groups (methylene groups contained in alicyclic hydrocarbon groups are adjacent to each other). , Groups in which oxygen atoms and carbonyl groups are substituted, respectively).
Especially, it is preferable that Y is a C3-C18 alicyclic hydrocarbon group which may have a substituent.

これらの例示の中でも、Ｙとしては、式（Ｙ１）〜式（Ｙ１９）のいずれかで表される基が好ましく、式（Ｙ１１）、式（Ｙ１４）、式（Ｙ１５）又は式（Ｙ１９）で表される基がさらに好ましく、式（Ｙ１１）又は式（Ｙ１４）で表される基がより好ましい。 The alicyclic hydrocarbon group for Y is preferably a group represented by any of the following formulas (Y1) to (Y26). Here, the groups represented by Formula (Y12) to Formula (Y26) are each selected from the group consisting of 1 to 3 methylene groups contained in the alicyclic hydrocarbon group each consisting of an oxygen atom, a sulfonyl group, or a carbonyl group. Corresponds to the group replaced by the selected group. In the groups represented by these formulas (Y1) to (Y26), * represents a bond bonded to L ^b1 .

Among these examples, Y is preferably a group represented by any one of formulas (Y1) to (Y19), and is represented by formula (Y11), formula (Y14), formula (Y15), or formula (Y19). The group represented is more preferable, and the group represented by the formula (Y11) or the formula (Y14) is more preferable.

Examples of the alicyclic hydrocarbon group formed by bonding an alkyl group to the carbon atom of the atoms constituting the ring include the following.

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

Examples of the alicyclic hydrocarbon group having an aromatic hydrocarbon group include the following.

Examples of the alicyclic hydrocarbon group having a group represented by — (CH ₂ ) _j2 —O—CO—R ^b1 include the following.

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

Examples of the sulfonate anion include sulfonate anions represented by the following formulas (b1-1-1) to (b1-1-9). In these sulfonate anions, L ^b1 is preferably a group represented by the formula (b1-1). R ^b2 and R ^b3 are each independently the same as those exemplified as the substituent that the aliphatic hydrocarbon group or alicyclic hydrocarbon group of Y may have, and have 1 to 4 carbon atoms. Are preferably an aliphatic hydrocarbon group and a hydroxy group, more preferably a methyl group and a hydroxy group.

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

A sulfonate anion in which Y is an unsubstituted alicyclic hydrocarbon group or an alicyclic hydrocarbon group having an aliphatic hydrocarbon group as a substituent, and L ^b1 is a group represented by the formula (b1-1) For example, the following may be mentioned.

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

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

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

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

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

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

Y is a alicyclic hydrocarbon group having a group represented by — (CH ₂ ) _j2 —O—CO—R ^b1 , and L ^b1 is a group represented by the formula (b1-2). Examples of the anion include the following.

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

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

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

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

Examples of the sulfonate anion in which Y is the sultone ring group and L ^b1 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 and L ^b1 is a divalent 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 ^b1 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 ^b1 is a divalent group represented by the formula (b1-3) include the following.

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

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

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

  Examples of the cation contained in the acid generator (B) include an onium cation, a sulfonium cation, an iodonium cation, an ammonium cation, a benzothiazolium cation, and a phosphonium cation. Among these, a sulfonium cation and an iodonium cation are preferable, and an arylsulfonium cation is more preferable.

As the organic cation (Z ⁺ ) in the acid generator (B), a sulfonium cation and an iodonium cation are preferable, and more preferable are the following formulas (b2-1), (b2-2), and (b2-3). And an organic cation represented by any one of formula (b2-4) [hereinafter, depending on the number of each formula, “cation (b2-1)”, “cation (b2-2)”, “cation (b2- 3) ”and“ cation (b2-4) ”. ].

In formula (b2-1) to formula (b2-4),
R ^b4 , R ^b5 and R ^b6 are each independently an aliphatic hydrocarbon group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms or an aromatic hydrocarbon group having 6 to 18 carbon atoms. Represents. The hydrogen atom contained in the aliphatic hydrocarbon group may be substituted with a hydroxy group, an alkoxy group having 1 to 12 carbon atoms or an aromatic hydrocarbon group having 6 to 18 carbon atoms, and the alicyclic hydrocarbon The hydrogen atom contained in the group may be substituted with a halogen atom, an acyl group having 2 to 4 carbon atoms or a glycidyloxy group, and the hydrogen atom contained in the aromatic hydrocarbon group includes a halogen atom, a hydroxy group, It may be substituted with an aliphatic hydrocarbon group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.
R ^b7 and R ^b8 each independently represent a hydroxy group, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.
m2 and n2 each independently represent an integer of 0 to 5.
R ^b9 and R ^b10 each independently represent an aliphatic hydrocarbon group having 1 to 18 carbon atoms or an alicyclic hydrocarbon group having 3 to 18 carbon atoms.
R ^b11 represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms.
R ^b9 , R ^b10 and R ^b11 are each independently an aliphatic hydrocarbon group or an alicyclic hydrocarbon group, and when these are aliphatic hydrocarbon groups, the carbon number thereof is 1 to 12 Is preferable, and when it is an alicyclic hydrocarbon group, the carbon number thereof is preferably 3 to 18, and more preferably 4 to 12.
R ^b12 represents an aliphatic hydrocarbon group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms. The hydrogen atom contained in the aromatic hydrocarbon group is an aliphatic hydrocarbon group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or 1 carbon atom. It may be substituted with ˜12 alkylcarbonyloxy groups.
The combination of R ^b9 and R ^b10 and / or the combination of R ^b11 and R ^b12 are each independently bonded to each other to form a 3- to 12-membered ring (preferably a 3- to 7-membered ring). An alicyclic hydrocarbon ring may be formed, and a methylene group contained in the alicyclic hydrocarbon ring may be replaced with an oxygen atom, a sulfur atom or a carbonyl group.

^{R b13, R b14, R b15} , R b16, R b17 and R ^b18 each independently represent a hydroxy group, an aliphatic hydrocarbon group or an alkoxy group having 1 to 12 carbon atoms having 1 to 12 carbon atoms.
L ^b11 represents an oxygen atom or a sulfur atom.
o2, p2, s2, and t2 each independently represents an integer of 0 to 5.
q2 and r2 each independently represents an integer of 0 to 4.
u2 represents 0 or 1.
When o2 is 2 or more, the plurality of R ^b13 may be the same or different from each other. When p2 is 2 or more, the plurality of R ^b14 may be the same or different from each other, and s2 is 2 or more. Sometimes, the plurality of R ^b15 may be the same or different from each other, and when t2 is 2 or more, the plurality of R ^b18 may be the same or different from each other.

^Examples of the alkylcarbonyloxy group for R ^b12 include methylcarbonyloxy group, ethylcarbonyloxy group, n-propylcarbonyloxy group, isopropylcarbonyloxy group, n-butylcarbonyloxy group, sec-butylcarbonyloxy group, tert-butyl. Examples thereof include a carbonyloxy group, a pentylcarbonyloxy group, a hexylcarbonyloxy group, an octylcarbonyloxy group, and a 2-ethylhexylcarbonyloxy group.

^Among the aliphatic hydrocarbon groups ^{represented by} R ^{b9 to} R ^b12 , preferred groups are, for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, pentyl group, A hexyl group, an octyl group, a 2-ethylhexyl group, and the like.
Among the alicyclic hydrocarbon groups represented by R ^{b9 to} R ^b11 , preferred groups are, for example, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclodecyl group, 2-alkyladamantan-2-yl group, 1 -(Adamantan-1-yl) alkane-1-yl group and isobornyl group.
^Among the aromatic hydrocarbon groups ^represented by R ^b12 , preferred groups are, for example, phenyl group, 4-methylphenyl group, 4-ethylphenyl group, 4-tert-butylphenyl group, 4-cyclohexylphenyl group, 4-methoxyphenyl. Group, biphenylyl group, naphthyl group and the like.
The aromatic hydrocarbon group having an aliphatic hydrocarbon group represented by R ^b12 includes an aralkyl group, and specifically includes a benzyl group.
Examples of the ring formed by combining the combination of R ^b9 and R ^b10 include, for example, a thiolane-1-ium ring (tetrahydrothiophenium ring), a thian-1-ium ring, and a 1,4-oxathian-4-ium ring. Etc.
Examples of the ring formed by combining the combination of R ^b11 and R ^b12 include an oxocycloheptane ring, an oxocyclohexane ring, an oxonorbornane ring, and an oxoadamantane ring.

式（ｂ２−１−１）中、
Ｒ^b19、Ｒ^b20及びＲ^b21は、それぞれ独立に、ハロゲン原子（より好ましくはフッ素原子）、ヒドロキシ基、炭素数１〜１８の脂肪族炭化水素基、炭素数３〜１８の脂環式炭化水素基又は炭素数１〜１２のアルコキシ基を表す。
該脂肪族炭化水素基としては、炭素数１〜１２の脂肪族炭化水素基が好ましく、炭素数１〜１２のアルキル基がより好ましい。該脂肪族炭化水素基は、置換基として、ヒドロキシ基、炭素数１〜１２のアルコキシ基又は炭素数６〜１８の芳香族炭化水素基を有していてもよい。
該脂環式炭化水素基の炭素数は４〜１８であることが好ましい。前記脂環式炭化水素基は、置換基として、ハロゲン原子、炭素数２〜４のアシル基又はグリシジルオキシ基を有していてもよい。
ｖ２、ｗ２及びｘ２は、それぞれ独立に０〜５の整数（好ましくは０又は１）を表す。
ｖ２が２以上のとき、複数のＲ^b19は互いに同一でも異なっていてもよく、ｗ２が２以上のとき、複数のＲ^b20は互いに同一でも異なっていてもよく、ｘ２が２以上のとき、複数のＲ^b21は互いに同一でも異なっていてもよい。
なかでも、Ｒ^b19、Ｒ^b20及びＲ^b21の各々は、ハロゲン原子（より好ましくはフッ素原子）、ヒドロキシ基、炭素数１〜１２のアルキル基、又は炭素数１〜１２のアルコキシ基であることが好ましい。 Among the exemplified organic cations, the cation (b2-1) is preferable, and an organic cation represented by the following formula (b2-1-1) [hereinafter referred to as “cation (b2-1-1)”. ], More preferably a triphenylsulfonium cation (in formula (b2-1-1), v2 = w2 = x2 = 0) or a tolylsulfonium cation (in formula (b2-1-1), v2 = w2 = X2 = 1, and R ¹⁹ , R ²⁰ and R ²¹ are all methyl groups).

In formula (b2-1-1),
R ^b19 , R ^b20 and R ^b21 each independently represent a halogen atom (more preferably a fluorine atom), a hydroxy group, an aliphatic hydrocarbon group having 1 to 18 carbon atoms, or an alicyclic hydrocarbon having 3 to 18 carbon atoms. Represents a group or an alkoxy group having 1 to 12 carbon atoms.
As this aliphatic hydrocarbon group, a C1-C12 aliphatic hydrocarbon group is preferable, and a C1-C12 alkyl group is more preferable. The aliphatic hydrocarbon group may have a hydroxy group, an alkoxy group having 1 to 12 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms as a substituent.
The alicyclic hydrocarbon group preferably has 4 to 18 carbon atoms. The alicyclic hydrocarbon group may have a halogen atom, an acyl group having 2 to 4 carbon atoms, or a glycidyloxy group as a substituent.
v2, w2 and x2 each independently represent an integer of 0 to 5 (preferably 0 or 1).
When v2 is 2 or more, the plurality of R ^b19 may be the same as or different from each other. When w2 is 2 or more, the plurality of R ^b20 may be the same or different from each other. R ^b21 may be the same as or different from each other.
Among them, each of R ^b19 , R ^b20 and R ^b21 is a halogen atom (more preferably a fluorine atom), a hydroxy group, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. preferable.

Specific examples of the cation (b2-1-1) include the following.

このような有機カチオンを有する酸発生剤（Ｂ）を含む本レジスト組成物は、より良好なフォーカスマージンでレジストパターンを製造することができるという利点もある。

The resist composition containing such an acid generator (B) having an organic cation has an advantage that a resist pattern can be produced with a better focus margin.

Specific examples of the cation (b2-2) include the following.

Specific examples of the cation (b2-3) include the following.

Specific examples of the cation (b2-4) include the following.

  The acid generator (B) is a combination of the above-described sulfonic acid anion and the above-mentioned organic cation, and these can be arbitrarily combined, but those represented by the formulas (b1-1-1) to (b1-1-9) Any of acid generator (B) which is a combination of a sulfonate anion and a cation (b2-1-1) represented by any one of formula (b1-1-3) to formula (b1-1-5) An acid generator (B) which is a combination of a sulfonate anion and a cation (b2-3) represented by

A more preferable acid generator (B) is a salt represented by any of the following formulas (B1-1) to (B1-17). Among these, a salt in which Y is an alicyclic hydrocarbon group which may have a substituent is preferable, and specifically, the formula (B1-1), the formula (B1-2), the formula (B1- 3), a salt represented by any one of formula (B1-4), formula (B1-5), formula (B1-6), formula (B1-11) and formula (B1-15) is more preferable. Further, in terms of easy production of the acid generator (B), an acid generator (B) containing a triphenylsulfonium cation or a tolylsulfonium cation is preferable, and the formula (B1-1), the formula ( B1-2), Formula (B1-6), Formula (B1-11), Formula (B1-12), Formula (B1-13) and (B1-14), and Formula (B1-3) The salts represented are more preferred.

<Basic Compound (hereinafter referred to as “Basic Compound (C)”)>
The resist composition preferably contains a basic compound (C). The “basic compound” as used herein means a compound having a property of capturing an acid, particularly a compound having a property of capturing an acid generated from an acid generator.

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、脂肪族炭化水素基（好ましくは、炭素数１〜６程度の脂肪族炭化水素基であり、さらに好ましくは、炭素数１〜６程度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程度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程度の芳香族炭化水素基である。）を表す。但し、該脂肪族炭化水素基、該脂環式炭化水素基及び該芳香族炭化水素基に含まれる水素原子は、ヒドロキシ基、アミノ基、又は炭素数１〜６のアルコキシ基で置換されていてもよく、該アミノ基はさらに、炭素数１〜４のアルキル基を有していてもよい。
Ｒ^c7は、脂肪族炭化水素基（好ましくは、炭素数１〜６程度の脂肪族炭化水素基であり、さらに好ましくは、炭素数１〜６程度のアルキル基である。）、炭素数１〜６程度のアルコキシ基、脂環式炭化水素基（好ましくは、炭素数５〜１０程度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程度のシクロアルキル基である。）又は芳香族炭化水素基（好ましくは、炭素数６〜１０程度の芳香族炭化水素基である。）を表す。但し、該脂肪族炭化水素基、該アルコキシ基、該脂環式炭化水素基及び該芳香族炭化水素基に含まれる水素原子は、ヒドロキシ基、アミノ基、又は炭素数１〜６のアルコキシ基で置換されていてもよく、該アミノ基はさらに、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いてもよい。 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. As the aliphatic amine, any of primary amine, secondary amine and tertiary amine can be used. The aromatic amine may be either an aromatic ring such as aniline with an amino group bonded thereto or a heteroaromatic amine such as pyridine. Preferable basic compounds (C) include aromatic amines represented by the following formula (C2), particularly 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 or an aliphatic hydrocarbon group (preferably an aliphatic hydrocarbon group having about 1 to 6 carbon atoms, more preferably an alkyl group having about 1 to 6 carbon atoms. Group), an alicyclic hydrocarbon group (preferably an alicyclic hydrocarbon group having about 5 to 10 carbon atoms) or an aromatic hydrocarbon group (preferably having about 6 to 10 carbon atoms). Represents an aromatic hydrocarbon group. However, the hydrogen atom contained in the aliphatic hydrocarbon group, the alicyclic hydrocarbon group, and the aromatic hydrocarbon group is 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 aliphatic hydrocarbon group (preferably an aliphatic hydrocarbon group having about 1 to 6 carbon atoms, more preferably an alkyl group having about 1 to 6 carbon atoms), or 1 to carbon atoms. About 6 alkoxy groups and alicyclic hydrocarbon groups (preferably an alicyclic hydrocarbon group having about 5 to 10 carbon atoms, and more preferably a cycloalkyl group having about 5 to 10 carbon atoms). Or an aromatic hydrocarbon group (preferably an aromatic hydrocarbon group having about 6 to 10 carbon atoms). However, the hydrogen atom contained in the aliphatic hydrocarbon group, the alkoxy group, the alicyclic hydrocarbon group, and the aromatic hydrocarbon group is a hydroxy group, an amino group, or an alkoxy group having 1 to 6 carbon atoms. It may be substituted, and 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.

ここで、
Ｒ^c8は、上記Ｒ^c7で説明したいずれかの基を表す。
Ｒ^c20、Ｒ^c21、Ｒ^c23、Ｒ^c24、Ｒ^c25、Ｒ^c26、Ｒ^c27及びＲ^c28の具体例は、上記Ｒ^c7で説明したいずれかの基を表す。
Ｒ^c9、Ｒ^c10、Ｒ^c11、Ｒ^c12、Ｒ^c13、Ｒ^c14、Ｒ^c16、Ｒ^c19及びＲ^c22の具体例は、前記の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いてもよく、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いてもよく、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いてもよく、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いてもよく、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いてもよく、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いてもよく、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いてもよい。
Ｒ^c15は、脂肪族炭化水素基（好ましくは、炭素数１〜６程度の脂肪族炭化水素基である。）、脂環式炭化水素基（好ましくは、炭素数３〜６程度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程度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は同一であっても異なってもよい。
Ｌ^c1及びＬ^c2は、それぞれ独立に、２価の脂肪族炭化水素基（好ましくは、炭素数１〜６程度の脂肪族炭化水素基であり、より好ましくは、炭素数１〜６程度のアルカンジイル基である。）、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。）、硫黄原子、ジスルフィド結合（−Ｓ−Ｓ−）又はこれらの組合せを表す。
Ｒ^c15の脂肪族炭化水素基は、好ましくは炭素数１〜６程度であり、脂環式炭化水素基は、好ましくは炭素数３〜６程度である。
アルカノイル基としては、アセチル基、２−メチルアセチル基、２，２−ジメチルアセチル基、プロピオニル基、ブチリル基、イソブチリル基、ペンタノイル基、２，２−ジメチルプロピオニル基等が挙げられ、好ましくは炭素数２〜６程度である。 In addition, a compound represented by any of the following formulas (C3) to (C11) can be used.

here,
R ^c8 represents any of the groups described for R ^c7 above.
Specific examples of ^{R c20, R c21, R c23} , R c24, R c25, R c26, R c27 and R ^{c 28} represents any of the groups described above R ^c7.
Specific examples of R ^c9 , R ^c10 , R ^c11 , R ^c12 , R ^c13 , R ^c14 , R ^c16 , R ^c19 and R ^c22 represent any of the groups described above for R ^c5 and R ^c6 .
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 q3 is 2 or more. when a plurality of R ^c24 may be the same or different, when r3 is 2 or more, plural R ^c25 may be the same or different, when s3 is 2 or more, plural R ^{c 26} when it may be the same or different, is t3 is 2 or more, plural R ^c27 may be the same or different, when u3 is 2 or more, the plurality of R ^{c 28} are identical or different from each other May be.
R ^c15 is an aliphatic hydrocarbon group (preferably an aliphatic hydrocarbon group having about 1 to 6 carbon atoms), an alicyclic hydrocarbon group (preferably an alicyclic group having about 3 to 6 carbon atoms). It is a hydrocarbon group.
) Or an alkanoyl group (preferably an alkanoyl group having about 2 to 6 carbon atoms).
n3 represents an integer of 0 to 8. When n3 is 2 or more, the plurality of R ^c15 may be the same or different.
L ^c1 and L ^c2 are each independently a divalent aliphatic hydrocarbon group (preferably an aliphatic hydrocarbon group having about 1 to 6 carbon atoms, more preferably an alkane having about 1 to 6 carbon atoms. A diyl group), a carbonyl group, —C (═NH) —, —C (═NR ^c3 ) — (wherein R ^c3 represents an alkyl group having 1 to 4 carbon atoms), a sulfur atom, and a disulfide. It represents a bond (—S—S—) or a combination thereof.
The aliphatic hydrocarbon group represented by R ^c15 preferably has about 1 to 6 carbon atoms, and the alicyclic hydrocarbon group preferably has about 3 to 6 carbon atoms.
Examples of the alkanoyl group include an acetyl group, a 2-methylacetyl group, a 2,2-dimethylacetyl group, a propionyl group, a butyryl group, an isobutyryl group, a pentanoyl group, and a 2,2-dimethylpropionyl group. It is about 2-6.

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, 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 Examples include '-dipyridyl disulfide, 2,2'-dipyridylamine, and 2,2'-dipiconylamine.
Examples of the compound (C11) include bipyridine.

  Examples of the basic 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, methyl Dioctylamine, methyldinonylamine, methyldidecylamine, ethyldibutylamine, ethyldipentylamine, ethyl Hexylamine, ethyldiheptylamine, ethyldioctylamine, ethyldinonylamine, ethyldidecylamine, dicyclohexylmethylamine, tris [2- (2-methoxyethoxy) ethyl] amine, triisopropanolamine ethylenediamine, tetramethylenediamine, hexa Examples include methylenediamine, 4,4′-diamino-1,2-diphenylethane, 4,4′-diamino-3,3′-dimethyldiphenylmethane, and 4,4′-diamino-3,3′-diethyldiphenylmethane. .

  Examples of ammonium hydroxide include tetramethylammonium hydroxide, tetraisopropylammonium hydroxide, tetrabutylammonium hydroxide, tetrahexylammonium hydroxide, tetraoctylammonium hydroxide, phenyltrimethylammonium hydroxide, and 3- (trifluoromethyl). Examples thereof include phenyltrimethylammonium hydroxide and choline.

  As a basic compound (C) used for this resist composition, diisopropyl aniline is preferable and 2, 6- diisopropyl aniline is more preferable.

<Solvent (D)>
The solvent (D) contained in the resist composition is a substrate in the production of a resist pattern, which will be described later, according to the type and amount of the resin (A) used and the type and amount of the acid generator (B). An optimum one can be appropriately selected from the viewpoint that the coating property when the resist composition is applied to the top 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 may contain components other than the resin (A), the acid generator (B), the solvent (D), and the basic compound (C) used as necessary, as necessary. . This component is referred to as “component (F)”. The component (F) is not particularly limited, and includes additives known in the resist field, such as sensitizers, dissolution inhibitors, surfactants, stabilizers, and dyes.

<Preparation method of the present resist composition>
This resist composition is obtained by mixing the resin (A), the acid generator (B) and the solvent (D), or the resin (A), the acid generator (B), the basic compound (C) and the solvent. It can be prepared by mixing (D). Further, the component (F) may be mixed as described above.
In such mixing, the mixing order is arbitrary and is not particularly limited. The temperature at the time of mixing can select an appropriate temperature range from the range of 10-40 degreeC according to the kind with respect to the kind of resin (A) to be used and the solubility with respect to solvents (D), such as resin (A). What is necessary is just to select mixing time according to mixing temperature, and 0.5 to 24 hours are preferable. The mixing means is not particularly limited, and stirring and mixing can be used.
The content of each component in the present resist composition can be adjusted by the amount of each component used in preparing the present resist composition.

The content ratio of the solvent (D) can be appropriately adjusted according to the type of the resin (A) as described above, but is preferably 90% by mass or more, more preferably 92% by mass with respect to the total mass of the resist composition. %, More preferably 94% by mass or more, preferably 99.9% by mass or less, more preferably 99% by mass or less. In the present resist composition in which the content ratio of the solvent (D) is 90% by mass, the solid content in the composition corresponds to 10% by mass. “Solid content” means the total of resist composition components excluding the solvent (E) described later. Solid content can be measured by well-known analysis means, such as a liquid chromatography or a gas chromatography, for example.
When the content of the solvent (D) is within the above range, for example, in a method for producing a resist pattern described later, a composition layer having a thickness of about 30 to 300 nm is easily formed. From this viewpoint, the content ratio of the solvent (D) with respect to the total mass of the resist composition is more preferably 92% by mass or more, and still more preferably 94% by mass or more. The upper limit of the content ratio of the solvent (D) is, for example, 99.9% by mass or less, and preferably 99% by mass or less.
The content of the solvent (D) can be controlled by the amount of the solvent (D) used in preparing the resist composition. After preparing the resist composition, the resist composition It can also be obtained by using a known analytical means such as liquid chromatography or gas chromatography.

  The content mass ratio of the resin (A) to the resist composition is preferably 80% by mass or more and 99% by mass or less with respect to the total mass of the solid content of the resist composition.

  The content ratio of the acid generator (B) to the resist composition is preferably 1 part by mass or more, more preferably 100 parts by mass of the total mass of the resin (A) contained in the resist composition. It is 3 parts by mass or more, preferably 30 parts by mass or less, and more preferably 25 parts by mass or less.

  When using a basic compound (C) for this resist composition, the content mass ratio has preferable about 0.01-1 mass% with respect to the total mass of solid content of this resist composition.

  Resin (A), an acid generator (B), a solvent (D), and each suitable content mass ratio of the basic compound (C) used as needed are also used when preparing this resist composition. It can be controlled by the amount of each used. After preparing the resist composition, the resist composition can be obtained by subjecting the resist composition to known analysis means such as gas chromatography and liquid chromatography.

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

  As described above, after mixing the components included in the resist composition, it is preferable to filter using a filter having a pore diameter of about 0.01 to 0.2 μm.

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

  Application of the resist composition 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. Various substrates to be subjected to microfabrication can be selected as the substrate before applying the resist composition. The substrate may be washed or an antireflection film may be formed before applying the resist composition. For example, a commercially available composition for an organic antireflection film can be used for forming the antireflection film.

In the drying in the step (2), the solvent [solvent (D)] is removed from the resist composition coated on the substrate, that is, the coated film. Such solvent removal is performed by evaporating the solvent from the coating film by, for example, heating means using a heating device such as a hot plate (so-called pre-baking), decompressing means using a decompressing device, or a combination of these means. It is performed by removing. The drying conditions can be selected according to the type of the solvent (D) contained in the resist composition. For example, in the case of heating using a hot plate, the surface temperature of the hot plate is set to a range of about 50 to 200 ° C. Is preferred. 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. Thus, the composition layer is formed on the substrate by removing the solvent from the coating film.

Step (3) is a step of exposing the composition layer, and preferably the composition layer is exposed using an exposure machine. At this time, 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), a solid-state laser light source (YAG In addition, various lasers such as a laser beam from a laser beam emitted 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).
As described above, by exposing through a mask, an exposed portion (exposed portion) and an unexposed portion (unexposed portion) are generated in the composition layer. In the composition layer of the exposed portion, the acid generator (B) contained in the composition layer receives exposure energy to generate an acid, and further, by the action with the generated acid, “is insoluble or hardly soluble in an alkaline aqueous solution. The acid labile group in the resin (A) possessed by the “resin that is soluble in an alkaline aqueous solution by the action of an acid” generates a hydrophilic group by a deprotection reaction, and as a result, the resin ( A) is soluble in an alkaline aqueous solution. On the other hand, since the exposure energy is not received in the unexposed area, the resin (A) remains insoluble or hardly soluble in the alkaline aqueous solution. Thus, since the composition layer in the exposed part and the composition layer in the unexposed part are remarkably different in solubility in the alkaline aqueous solution, a resist pattern can be formed by development with the alkaline aqueous solution.

  In the step (4), a heat treatment (so-called post-exposure baking) for further promoting the progress of the deprotecting group reaction that may occur in the exposed portion is performed. Such heat treatment is preferably the heating means using the hot plate shown in the step (2). In addition, when performing hot plate heating in a process (4), about 50-200 degreeC is preferable and the surface temperature of this hot plate has more preferable about 70-150 degreeC. 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. The term “development” as used herein refers to removing the composition layer in the exposed area by dissolving it in the aqueous alkali solution by bringing the heated composition layer into contact with the aqueous alkali solution. Since the composition layer in the unexposed area is insoluble or hardly soluble in the alkaline aqueous solution as described above, it remains on the substrate, and a resist pattern is produced 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 the development, it is preferable to perform a rinsing treatment with ultrapure water or the like, and to further remove water remaining on the substrate and the resist pattern.

  Thus, the resist pattern manufactured on the substrate has an extremely excellent LER.

<Application>
This resist composition is useful as a resist composition for KrF excimer laser exposure, a resist composition for ArF excimer laser exposure, and a resist composition for electron beam (EB) irradiation or a resist composition for EUV exposure. It is also useful as a product. Moreover, it can utilize suitably as a resist composition for immersion exposure.

The present invention will be described more specifically with reference to examples. In the examples, “%” and “part” representing the content mass ratio or the 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 the amount of unreacted monomer in the reaction liquid after the polymerization is finished. It measured using the chromatography, and computed by calculating | requiring the monomer amount used for superposition | polymerization from the obtained result. The weight average molecular weight is a value determined by gel permeation chromatography. The conditions for gel permeation chromatography analysis are as follows.
Column: TSKgel Multipore HXL-M x 3 + guardcolumn (manufactured by Tosoh Corporation)
Eluent: Tetrahydrofuran Flow rate: 1.0 mL / min
Detector: RI detector Column temperature: 40 ° C
Injection volume: 100 μl
Molecular weight standard: Standard polystyrene (manufactured by Tosoh Corporation)

以下、これらのモノマーを「モノマー（Ａ）」〜「モノマー（Ｈ）」、「モノマー（ａ−１）」、「モノマー（ａ−２）」という。 Synthesis example (synthesis of resin (A), etc.)
The compounds (monomers) used in the resin synthesis are shown below.

Hereinafter, these monomers are referred to as “monomer (A)” to “monomer (H)”, “monomer (a-1)”, and “monomer (a-2)”.

Synthesis Example 1 [Synthesis of Resin A1]
Monomer (F), monomer (a-1), monomer (G), monomer (B), monomer (C) and monomer (D) are mixed in a molar ratio [monomer (F): monomer (a-1): monomer. (G): monomer (B): monomer (C): monomer (D)] are mixed in a ratio of 20: 10: 14: 6: 20: 30, and all the monomers are added to this monomer mixture. The total mass of was mixed with 1.5 mass times dioxane. Into the obtained mixture, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were respectively added to 1.00 mol% and 3.00 mol% with respect to the total number of moles of all monomers. Polymerization was carried out by heating at 75 ° C. for about 5 hours. Thereafter, the polymerization reaction solution was poured into a large amount of a mixed solvent of methanol and water (mass ratio methanol: water = 4: 1) to precipitate the resin. This resin was filtered and collected. The recovered resin is again dissolved in dioxane, and this solution is poured into a large amount of methanol / water mixed solvent to precipitate the resin, and the precipitated resin is filtered and recovered twice. By precipitation purification, a copolymer having a weight average molecular weight of about 7.5 × 10 ³ was obtained with a yield of 68%. This copolymer has the following structural units derived from the monomer (F), the monomer (a-1), the monomer (G), the monomer (B), the monomer (C) and the monomer (D), respectively. Yes, this is resin A1.

Synthesis Example 2 [Synthesis of Resin A2]
Monomer (E), monomer (a-1), monomer (G), monomer (B), monomer (C), and monomer (D) are in a molar ratio [monomer (E): monomer (a-1): monomer (G): monomer (B): monomer (C): monomer (D)] are mixed in a ratio of 20: 10: 14: 6: 20: 30, and all the monomers are added to this monomer mixture. The total mass of was mixed with 1.5 mass times dioxane. Into the obtained mixture, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were respectively added to 1.00 mol% and 3.00 mol% with respect to the total number of moles of all monomers. Polymerization was carried out by heating at 75 ° C. for about 5 hours. Thereafter, the polymerization reaction solution was poured into a large amount of a mixed solvent of methanol and water (mass ratio methanol: water = 4: 1) to precipitate the resin. This resin was filtered and collected. The recovered resin is again dissolved in dioxane, and this solution is poured into a large amount of methanol / water mixed solvent to precipitate the resin, and the precipitated resin is filtered and recovered twice. By precipitation purification, a copolymer having a weight average molecular weight of about 7.3 × 10 ³ was obtained in a yield of 73%. This copolymer has the following structural units derived from monomer (E), monomer (a-1), monomer (G), monomer (B), monomer (C) and monomer (D), respectively. Yes, this is resin A2.

Synthesis Example 3 [Synthesis of Resin A3]
Monomer (E), monomer (a-2), monomer (G), monomer (B), monomer (C), and monomer (D) are in a molar ratio [monomer (E): monomer (a-2): monomer (G): monomer (B): monomer (C): monomer (D)] are mixed in a ratio of 20: 10: 14: 6: 20: 30, and all the monomers are added to this monomer mixture. The total mass of was mixed with 1.5 mass times dioxane. Into the obtained mixture, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were respectively added to 1.00 mol% and 3.00 mol% with respect to the total number of moles of all monomers. Polymerization was carried out by heating at 75 ° C. for about 5 hours. Thereafter, the polymerization reaction solution was poured into a large amount of a mixed solvent of methanol and water (mass ratio methanol: water = 4: 1) to precipitate the resin. This resin was filtered and collected. The recovered resin is again dissolved in dioxane, and this solution is poured into a large amount of methanol / water mixed solvent to precipitate the resin, and the precipitated resin is filtered and recovered twice. By precipitation purification, a copolymer having a weight average molecular weight of about 7.8 × 10 ³ was obtained with a yield of 70%. This copolymer has the following structural units derived from the monomer (E), the monomer (a-2), the monomer (G), the monomer (B), the monomer (C) and the monomer (D), respectively. Yes, this is resin A3.

Synthesis Example 4 [Synthesis of Resin A4]
The monomer (A), monomer (a-1), and monomer (B) have a molar ratio [monomer (A): monomer (a-1): monomer (B)] of 37.5: 37.5: It mixed so that it might become a ratio of 25, and also 1.5 mass times dioxane was mixed with this monomer mixture with respect to the total mass of all the monomers. Into the obtained mixture, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were respectively added to 1.00 mol% and 3.00 mol% with respect to the total number of moles of all monomers. Polymerization was carried out by heating at 75 ° C. for about 5 hours. Thereafter, the polymerization reaction solution was poured into a large amount of a mixed solvent of methanol and water (mass ratio methanol: water = 4: 1) to precipitate the resin. This resin was filtered and collected. The recovered resin is again dissolved in dioxane, and this solution is poured into a large amount of methanol / water mixed solvent to precipitate the resin, and the precipitated resin is filtered and recovered twice. By precipitation purification, a copolymer having a weight average molecular weight of about 7.3 × 10 ³ was obtained in a yield of 63%. This copolymer has the following structural units derived from the monomer (A), the monomer (a-1), and the monomer (B), respectively, and is designated as resin A4.

Synthesis Example 5 [Synthesis of Resin A5]
Monomer (E), monomer (a-1), monomer (H), monomer (B), monomer (C), and monomer (D) are in a molar ratio [monomer (E): monomer (a-1): monomer (H): monomer (B): monomer (C): monomer (D)] are mixed at a ratio of 20: 10: 14: 6: 20: 30, and all the monomers are added to this monomer mixture. The total mass of was mixed with 1.5 mass times dioxane. Into the obtained mixture, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were respectively added to 1.00 mol% and 3.00 mol% with respect to the total number of moles of all monomers. Polymerization was carried out by heating at 75 ° C. for about 5 hours. Thereafter, the polymerization reaction solution was poured into a large amount of a mixed solvent of methanol and water (mass ratio methanol: water = 4: 1) to precipitate the resin. This resin was filtered and collected. The recovered resin is again dissolved in dioxane, and this solution is poured into a large amount of methanol / water mixed solvent to precipitate the resin, and the precipitated resin is filtered and recovered twice. By precipitation purification, a copolymer having a weight average molecular weight of about 7.9 × 10 ³ was obtained with a yield of 71%. This copolymer has the following structural units derived from the monomer (E), the monomer (a-1), the monomer (H), the monomer (B), the monomer (C) and the monomer (D), respectively. Yes, this is resin A5.

Synthesis Example 6 [Synthesis of Resin A6]
Monomer (E), monomer (a-2), monomer (H), monomer (B), monomer (C), and monomer (D) are in a molar ratio [monomer (E): monomer (a-2): monomer (H): monomer (B): monomer (C): monomer (D)] are mixed at a ratio of 20: 10: 14: 6: 20: 30, and all the monomers are added to this monomer mixture. The total mass of was mixed with 1.5 mass times dioxane. Into the obtained mixture, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were respectively added to 1.00 mol% and 3.00 mol% with respect to the total number of moles of all monomers. Polymerization was carried out by heating at 75 ° C. for about 5 hours. Thereafter, the polymerization reaction solution was poured into a large amount of a mixed solvent of methanol and water (mass ratio methanol: water = 4: 1) to precipitate the resin. This resin was filtered and collected. The recovered resin is again dissolved in dioxane, and this solution is poured into a large amount of methanol / water mixed solvent to precipitate the resin, and the precipitated resin is filtered and recovered twice. By precipitation purification, a copolymer having a weight average molecular weight of about 7.8 × 10 ³ was obtained in a yield of 75%. This copolymer has the following structural units derived from monomer (E), monomer (a-2), monomer (H), monomer (B), monomer (C) and monomer (D), respectively. Yes, this is resin A6.

<Preparation of resist composition>
Resin A1 to Resin A4 obtained in Synthesis Example 1;
Acid generator B1 to acid generator B3 shown below;
Basic compound C1 shown below;
Each was dissolved in the solvent shown below in parts by mass shown in Table 1, and further filtered through a fluororesin filter having a pore diameter of 0.2 μm to prepare a resist composition.

Ｂ２：式（Ｂ−２）で表される塩

Ｂ３：みどり化学（株）製ＴＰＳ−１０９
〔トリフェニルスルホニウム ペルフルオロブタンスルホネート〕 <Resin>
A1 to A6: Resin A1 to Resin A6 obtained in each of Synthesis Examples 1 to 6
<Acid generator>
B1: Salt represented by the formula (B-1)

B2: salt represented by formula (B-2)

B3: Midori Chemical Co., Ltd. TPS-109
[Triphenylsulfonium perfluorobutanesulfonate]

<Basic compound: Quencher>
C1: 2,6-diisopropylaniline <solvent>
Propylene glycol monomethyl ether acetate 265.0 parts Propylene glycol monomethyl ether 20.0 parts 2-heptanone 20.0 parts γ-butyrolactone 3.5 parts

<Manufacture of resist pattern>
An organic antireflective coating composition [ARC-29; manufactured by Nissan Chemical Industries, Ltd.] was applied onto a 12-inch silicon wafer and baked at 205 ° C. for 60 seconds to obtain a thickness of 78 nm. 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 application of the resist composition, the obtained silicon wafer was pre-baked (PB) with a direct hot plate at a temperature described in the “PB” column of Table 1 for 60 seconds. Using the ArF excimer laser stepper for immersion exposure [XT: 1900 Gi; manufactured by ASML, NA = 1.35, 3/4 Annular XY polarized light] on the wafer having the resist composition film formed thereon, the exposure amount is stepped. 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 bake (PEB) is performed on the hot plate at a temperature described in the “PEB” column of Table 1 for 60 seconds, and further with a 2.38 mass% tetramethylammonium hydroxide aqueous solution for 60 seconds. Paddle development was performed to obtain a resist pattern.

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

<Line edge roughness evaluation (LER)>
Observe the wall surface of the obtained resist pattern with a scanning electron microscope,
“E” (excellent) for 4.0 nm or less,
“G” (good), which is 4.5 nm or less,
What exceeds 4.5nm is "b" (bad)
It was. The results are shown in Table 2.

  The resist pattern obtained from this resist composition has a result of “e” or “g” in the line edge roughness evaluation (LER), so that it was confirmed that a resist pattern having excellent LER can be produced.

  The resist composition of the present invention can produce a resist pattern having excellent line edge roughness (LER).

Claims (6)

(A) Resist composition comprising a resin having a structural unit derived from the compound represented by formula (a) and (B) a salt represented by formula (B1).

[In the formula (a),
R ¹ represents a hydrogen atom or a methyl group.
Ring W represents an alicyclic hydrocarbon ring having 4 to 36 carbon atoms, and the methylene group contained in the alicyclic hydrocarbon ring may be replaced with an oxygen atom, a sulfur atom, a carbonyl group or a sulfonyl group. .
X ^x represents a single bond or -A-CO-O-.
A represents a C1-C10 hydrocarbon group. ]

[In the formula (B1),
Q ¹ and Q ² each independently represents a fluorine atom or a C 1-6 perfluoroalkyl group.
L ^b1 represents a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, and the methylene group contained in 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 which may have a substituent or an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent; The methylene group contained in the aromatic hydrocarbon group may be replaced with an oxygen atom, a sulfonyl group or a carbonyl group, and the methylene group contained in the alicyclic hydrocarbon group is substituted with an oxygen atom, a sulfonyl group or a carbonyl group. It may be.
Z ⁺ represents an organic cation. ] In the formula (a)

[Wherein W represents the same meaning as described above. * Represents a bond. ]
The resist composition according to claim 1, wherein the group represented by formula (a) is a group represented by formula (a-1A) or a group represented by formula (a-2A).

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

[In the formula (a-2A),
The methylene group contained in the cyclohexane ring may be replaced with an oxygen atom, a sulfur atom, a carbonyl group or a sulfonyl group. The hydrogen atom contained in the cyclohexane ring is a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms, or an aromatic group having 6 to 10 carbon atoms. It may be replaced by a group hydrocarbon group.
] In addition to the structural unit derived from the compound represented by the formula (a), the (A) is represented by the structural unit derived from the compound represented by the formula (a1-1) and the formula (a1-2). The resist composition according to claim 1 or 2, which is a resin having at least one selected from the group consisting of structural units derived from compounds.

[In the formula (a1-1),
L ^a1 represents an oxygen atom or a group represented by ^* —O— (CH ₂ ) _k1 —CO—O—. * Represents a bond with a carbonyl group.
k1 represents an integer of 1 to 7.
R ^a4 represents a hydrogen atom or a methyl group.
R ^a6 represents an aliphatic hydrocarbon 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.
In formula (a1-2),
L ^a2 represents an oxygen atom or a group represented by ^* —O— (CH ₂ ) _k2 —CO—O—. * Is a bond to a carbonyl group.
k2 represents an integer of 1 to 7.
R ^a5 represents a hydrogen atom or a methyl group.
R ^a7 represents an aliphatic hydrocarbon group having 1 to 8 carbon atoms or an alicyclic hydrocarbon group having 3 to 10 carbon atoms.
n1 represents an integer of 0 to 10.
n1 ′ represents an integer of 0 to 3. ] In addition to the structural unit derived from the compound represented by the formula (a), the (A) is represented by the structural unit derived from the compound represented by the formula (a3-1) and the formula (a3-2). The resist composition according to any one of claims 1 to 3, which is a resin having at least one selected from the group consisting of a structural unit derived from a compound and a structural unit derived from a compound represented by formula (a3-3). .

[In the formula (a3-1),
L ^a4 represents an oxygen atom or ^* —O— (CH ₂ ) _k3 —CO—O—. * Represents a bond with a carbonyl group.
k3 represents an integer of 1 to 7.
R ^a18 represents a hydrogen atom or a methyl group.
R ^a21 represents an aliphatic hydrocarbon group having 1 to 4 carbon atoms. p1 represents an integer of 0 to 5, and when p1 is 2 or more, a plurality of R ^a21 may be the same or different.
In formula (a3-2),
L ^a5 represents an oxygen atom or ^* —O— (CH ₂ ) _k3 —CO—O—. * Represents a bond with a carbonyl group.
R ^a22 represents a carboxy group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms. q1 represents an integer of 0 to 3, and when q1 is 2 or more, a plurality of ^Ra22s may be the same or different.
In formula (a3-3),
L ^a6 represents an oxygen atom or ^* —O— (CH ₂ ) _k3 —CO—O—. * Represents a bond with a carbonyl group.
R ^a20 represents a hydrogen atom or a methyl group.
R ^a23 represents a carboxy group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms. r1 represents an integer of 0 to 3, and when r1 is 2 or more, a plurality of ^Ra23s may be the same or different. ]   The resist composition according to claim 1, wherein Y in the formula (B1) is an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent. (1) The process of apply | coating the resist composition in any one of Claims 1-5 on a board | substrate,
(2) The process of drying the composition after application | coating and forming a composition layer,
(3) a step of exposing the composition layer,
(4) A step of heating the composition layer after exposure,
(5) a step of developing the composition layer after heating;
A method for producing a resist pattern including: