JP2012167084A - Salt, resist composition, and method for producing resist pattern - Google Patents

Abstract

［式中、Ｑ^１及びＱ^２は、互いに独立に、フッ素原子又はペルフルオロアルキル基を表す；Ｌ^１は、２価の飽和炭化水素基を表し、該飽和炭化水素基を構成しているメチレン基は、酸素原子又はカルボニル基で置き換わっていてもよい；ｓは０〜３の整数；Ｒ^１は、ｓが１の場合アルキル基を表し、ｓが２又は３の場合互いに独立してアルキル基を表すか、あるいは同一の炭素元素に結合する２つのＲ^１が該炭素原子とともにカルボニル基を形成してもよく、前記アルキル基を構成しているメチレン基は、酸素原子又はカルボニル基で置き換わっていてもよい；Ｚ^＋は、有機対イオンを表す。］
【選択図】なしAn object of the present invention is to provide a salt, an acid generator, and a resist composition capable of obtaining a resist pattern having an excellent focus margin.
A salt represented by formula (I).

[Wherein, Q ¹ and Q ² independently of each other represent a fluorine atom or a perfluoroalkyl group; L ¹ represents a divalent saturated hydrocarbon group, and the methylene group constituting the saturated hydrocarbon group May be replaced by an oxygen atom or a carbonyl group; s is an integer of 0 to 3; R ¹ represents an alkyl group when s is 1, and an alkyl group independently of each other when s is 2 or 3. Or two R ¹ bonded to the same carbon element may form a carbonyl group together with the carbon atom, and the methylene group constituting the alkyl group is replaced by an oxygen atom or a carbonyl group. Z ⁺ represents an organic counter ion. ]
[Selection figure] None

Description

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

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

JP 2007-161707 A

  Even when a conventionally known resist composition containing the acid generator is used as an ArF resist composition, the focus margin (DOF) of the resulting resist pattern may not always be sufficiently satisfied.

［式（Ｉ）中、
Ｑ^１及びＱ^２は、互いに独立に、フッ素原子又は炭素数１〜６のペルフルオロアルキル基を表す。
Ｌ^１は、炭素数１〜１７の２価の飽和炭化水素基を表し、該飽和炭化水素基を構成しているメチレン基は、酸素原子又はカルボニル基で置き換わっていてもよい。
ｓは、０〜３の整数を表す。
Ｒ^１は、ｓが１の場合、炭素数１〜６のアルキル基を表し、ｓが２又は３の場合、互いに独立して炭素数１〜６のアルキル基を表すか、あるいは同一の炭素元素に結合する２つのＲ^１が該炭素原子とともにカルボニル基を形成してもよく、該アルキル基を構成しているメチレン基は、酸素原子又はカルボニル基で置き換わっていてもよい。
Ｚ^＋は、有機対イオンを表す。］
〔２〕前記Ｌ^１が、＊−ＣＯ−Ｏ−（ＣＨ_２）_ｕ−（ｕは０〜６の整数を表す。＊は、−Ｃ（Ｑ^１）（Ｑ^２）−との結合手を表す。）である前記〔１〕記載の塩。
〔３〕前記Ｚ^＋が、アリールスルホニウムカチオンである前記〔１〕又は前記〔２〕記載の塩。
〔４〕前記〔１〕〜前記〔３〕のいずれか一項記載の塩を有効成分として含有する酸発生剤。
〔５〕前記〔４〕記載の酸発生剤と樹脂とを含有し、該樹脂は酸に不安定な基を有し、かつアルカリ水溶液に不溶又は難溶であり、酸と作用してアルカリ水溶液で溶解し得る樹脂であるレジスト組成物。
〔６〕さらに塩基性化合物を含有する前記〔５〕記載のレジスト組成物。
〔７〕（１）前記〔５〕又は前記〔６〕記載のレジスト組成物を基板上に塗布する工程、
（２）塗布後の組成物を乾燥させて組成物層を形成する工程、
（３）組成物層に露光機を用いて露光する工程、
（４）露光後の組成物層を加熱する工程及び
（５）加熱後の組成物層を現像する工程を含むレジストパターンの製造方法。 The present invention includes the following inventions.
[1] A salt represented by the formula (I).

[In the formula (I),
Q ¹ and Q ² each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group.
L ¹ represents a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, and the methylene group constituting the saturated hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
s represents an integer of 0 to 3.
R ¹ represents an alkyl group having 1 to 6 carbon atoms when s is 1, and represents an alkyl group having 1 to 6 carbon atoms independently of each other when s is 2 or 3, or the same carbon element Two R ¹ bonded to each other may form a carbonyl group together with the carbon atom, and the methylene group constituting the alkyl group may be replaced with an oxygen atom or a carbonyl group.
Z ⁺ represents an organic counter ion. ]
[2] L ¹ represents * —CO—O— (CH ₂ ) _u — (u represents an integer of 0 to 6. * represents a bond with —C (Q ¹ ) (Q ² ) —. The salt according to [1], wherein
[3] The salt according to [1] or [2] above, wherein Z ⁺ is an arylsulfonium cation.
[4] An acid generator containing the salt according to any one of [1] to [3] as an active ingredient.
[5] The acid generator according to the above [4] and a resin, wherein the resin has an acid labile group and is insoluble or hardly soluble in an aqueous alkali solution, and acts on the acid to react with the aqueous alkali solution. A resist composition, which is a resin that can be dissolved in
[6] The resist composition according to [5], further containing a basic compound.
[7] (1) A step of applying the resist composition according to [5] or [6] on a substrate,
(2) The process of drying the composition after application | coating and forming a composition layer,
(3) a step of exposing the composition layer using an exposure machine;
(4) A method for producing a resist pattern, comprising a step of heating the composition layer after exposure, and (5) a step of developing the composition layer after heating.

  By using the salt of the present invention as an acid generator for a resist composition, for example, a resist pattern having an excellent focus margin (DOF) can be produced as a resist composition for ArF. The obtained resist pattern has a top shape and a bottom shape that are close to a rectangle and are excellent.

It is a figure showing the cross-sectional shape of the resist pattern formed using the resist composition of this invention.

  In the present specification, unless otherwise specified, in the description of the structural formula of the compound, the following examples of substituents are applied to any structural formula having the same substituent while appropriately selecting the number of carbon atoms. . Those which can be linear, branched or cyclic include any of them, and they may be mixed. When stereoisomers exist, all stereoisomers are included. * Represents a bond.

The hydrocarbon group includes an aliphatic hydrocarbon group and an aromatic hydrocarbon group.
The aliphatic hydrocarbon group includes both a chain and a cyclic group, and includes a combination of a chain and a cyclic aliphatic hydrocarbon group unless otherwise defined. Moreover, although these aliphatic hydrocarbon groups may contain the carbon-carbon double bond in the part, a saturated group is preferable.
Of the chain aliphatic hydrocarbon groups, the monovalent one typically includes an alkyl group.
Examples of the alkyl group include a methyl group (C ₁ ), an ethyl group (C ₂ ), a propyl group (C ₃ ), a butyl group (C ₄ ), a pentyl group (C ₅ ), a hexyl group (C ₆ ), a heptyl group ( C ₇ ), octyl group (C ₈ ), decyl group (C ₁₀ ), dodecyl group (C ₁₂ ), hexadecyl group (C ₁₄ ), pentadecyl group (C ₁₅ ), hexyldecyl group (C ₁₆ ), heptadecyl group ( C ₁₇ ) and octadecyl group (C ₁₈ ).
Examples of the divalent group of chain aliphatic hydrocarbon groups include alkanediyl groups in which one hydrogen atom has been removed from an alkyl group.
Examples of alkanediyl groups include 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, ethane-1,1-diyl group, propane-1,1-diyl group and propane-2,2-diyl group, butane-1,3-diyl group, 2-methylpropane-1,3 − Yl group, 2-methylpropane-1,2-diyl, pentane-1,4-diyl group, a 2-methylbutane-1,4-diyl group.

  The cyclic aliphatic hydrocarbon group (hereinafter sometimes referred to as “alicyclic hydrocarbon group”) typically means a cycloalkyl group, and includes any of the monocyclic and polycyclic groups shown below. Is also included.

As a monovalent alicyclic hydrocarbon group, a monocyclic aliphatic hydrocarbon group represents 1 hydrogen atom of a cycloalkane represented by the following formulas (KA-1) to (KA-7). It is a group that has been removed.

The polycyclic aliphatic hydrocarbon group is a group in which one hydrogen atom of a cycloalkane represented by the following formulas (KA-8) to (KA-22) is removed.

Examples of the divalent alicyclic hydrocarbon group include groups in which two hydrogen atoms have been removed from the alicyclic hydrocarbon of formula (KA-1) to formula (KA-22).
Of the monocyclic and polycyclic aliphatic hydrocarbon groups described above, a particularly saturated group is sometimes referred to as a “saturated cyclic hydrocarbon group”. Of the above aliphatic hydrocarbon groups, a particularly saturated group is sometimes referred to as a “saturated hydrocarbon group”.

The aliphatic hydrocarbon group may have a substituent. Examples of the substituent include a halogen atom, a hydroxy group, an alkoxy group, an alkylthio group, an acyl group, an acyloxy group, an aryl group, an aralkyl group, and an aryloxy group, unless otherwise specified.
Here, as a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom are mentioned.
Examples of alkoxy groups include methoxy group (C ₁ ), ethoxy group (C ₂ ), propoxy group (C ₃ ), butoxy group (C ₄ ), pentyloxy group (C ₅ ), hexyloxy group (C ₆ ), heptyl Examples thereof include an oxy group (C ₇ ), an octyloxy group (C ₈ ), a decyloxy group (C ₁₀ ), and a dodecyloxy group (C ₁₂ ).
Examples of the alkylthio group include those in which an oxygen atom of an alkoxy group is replaced by a sulfur atom, such as a methylthio group, an ethylthio group, a propylthio group, a butylthio group, a pentylthio group, a hexylthio group, a heptylthio group, an octylthio group, a decylthio group, and the like. Examples include dodecylthio group.
Examples of the acyl group include acetyl group (C ₂ ), propionyl group (C ₃ ), butyryl group (C ₄ ), valeryl group (C ₅ ), hexanoyl group (C ₆ ), heptanoyl group (C ₇ ), octanoyl group ( Examples include those in which an alkyl group such as C ₈ ), decanoyl group (C ₁₀ ) and dodecanoyl group (C ₁₂ ) and a carbonyl group are bonded, and those in which an aryl group such as benzoyl group (C ₇ ) and a carbonyl group are bonded. It is done.
Examples of the acyloxy group include an acetyloxy group, a propionyloxy group, a butyryloxy group, and an isobutyryloxy group.
Examples of the aralkyl group include benzyl group (C ₇ ), phenethyl group (C ₈ ), phenylpropyl group (C ₉ ), naphthylmethyl group (C ₁₁ ), and naphthylethyl group (C ₁₂ ).
Aryloxy groups include phenyloxy group (C ₆ ), naphthyloxy group (C ₁₀ ), anthryloxy group (C ₁₄ ), biphenyloxy group (C ₁₂ ), phenanthryloxy group (C ₁₄ ) and full A combination of an aryl group such as an oleenyloxy group (C ₁₃ ) and an oxygen atom is exemplified.

A typical example of the aromatic hydrocarbon group is an aryl group.
Examples of the aryl group include a phenyl group (C ₆ ), a naphthyl group (C ₁₀ ), an anthryl group (C ₁₄ ), a biphenyl group (C ₁₂ ), a phenanthryl group (C ₁₄ ), and a fluorenyl group (C ₁₃ ). .
The aromatic hydrocarbon group may have a substituent. Unless such a substituent is particularly limited, a halogen atom, a hydroxy group, an alkoxy group, an acyl group, an acyloxy group, an alkyl group, and an aryloxy group are exemplified.

  The saturated hydrocarbon group means a saturated group among the above-described aliphatic hydrocarbon groups, that is, a saturated group among the above-described chain and cyclic aliphatic hydrocarbon groups. Further, the saturated hydrocarbon group may have the same substituent as the aliphatic hydrocarbon group.

Further, "(meth) acrylic monomer" means at least one monomer having a structure of "CH ₂ = CH-CO-" or _{"CH 2 = C (CH 3)} -CO- ". Similarly, “(meth) acrylate” and “(meth) acrylic acid” mean “at least one of acrylate and methacrylate” and “at least one of acrylic acid and methacrylic acid”, respectively.

［式（Ｉ）中、
Ｑ^１及びＱ^２は、互いに独立に、フッ素原子又は炭素数１〜６のペルフルオロアルキル基を表す。
Ｌ^１は、炭素数１〜１７の２価の飽和炭化水素基を表し、該飽和炭化水素基を構成しているメチレン基は、酸素原子又はカルボニル基で置き換わっていてもよい。
ｓは、０〜３の整数を表す。
Ｒ^１は、ｓが１の場合、炭素数１〜６のアルキル基を表し、ｓが２又は３の場合、互いに独立して炭素数１〜６のアルキル基を表すか、あるいは同一の炭素元素に結合する２つのＲ^１が該炭素原子とともにカルボニル基を形成してもよく、該アルキル基を構成しているメチレン基は、酸素原子又はカルボニル基で置き換わっていてもよい。
Ｚ^＋は、有機対イオンを表す。］
以下の説明において、塩（Ｉ）のうち、正電荷を有するＺ^＋で示される有機カチオンを除去してなる負電荷を有するものを「スルホン酸アニオン」ということがある。 <Salt represented by formula (I)>
The salt of the present invention is represented by the formula (I) (hereinafter sometimes referred to as “salt (I)”).

[In the formula (I),
Q ¹ and Q ² each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group.
L ¹ represents a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, and the methylene group constituting the saturated hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
s represents an integer of 0 to 3.
R ¹ represents an alkyl group having 1 to 6 carbon atoms when s is 1, and represents an alkyl group having 1 to 6 carbon atoms independently of each other when s is 2 or 3, or the same carbon element Two R ¹ bonded to each other may form a carbonyl group together with the carbon atom, and the methylene group constituting the alkyl group may be replaced with an oxygen atom or a carbonyl group.
Z ⁺ represents an organic counter ion. ]
In the following description, the salt (I) having a negative charge obtained by removing the organic cation represented by Z ⁺ having a positive charge may be referred to as a “sulfonate anion”.

  Examples of the perfluoroalkyl group include a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group, a perfluorotert-butyl group, a perfluoropentyl group, and a perfluorohexyl group. Can be mentioned.

In the formula (I), Q ¹ and Q ² are preferably each independently a trifluoromethyl group or a fluorine atom, and more preferably a fluorine atom.

Examples of the group in which the methylene group constituting the saturated hydrocarbon group represented by L ¹ is replaced with an oxygen atom or a carbonyl group include any of the following formulas (b1-1) to (b1-7): The group shown by these is mentioned. L ¹ is preferably a group represented by any one of formulas (b1-1) to (b1-4), more preferably a group represented by formula (b1-1) or formula (b1-3). is there. In the formulas (b1-1) to (b1-7), the left and right sides are described in accordance with the formula (I). Of the two bonds indicated by *, the left bond is C (Q ¹ ) It is bonded to the carbon atom of (Q ² ). The same applies to specific examples of the following formulas (b1-1) to (b1-7).

式（ｂ１−１）〜式（ｂ１−７）中、
Ｌ^b2は、単結合又は炭素数１〜１５の２価の飽和炭化水素基を表す。
Ｌ^b3は、単結合又は炭素数１〜１２の２価の飽和炭化水素基を表す。
Ｌ^b4は、炭素数１〜１３の２価の飽和炭化水素基を表す。但しＬ^b3及びＬ^b4の合計炭素数の上限は１３である。
Ｌ^b5は、炭素数１〜１５の２価の飽和炭化水素基を表す。
Ｌ^b6は、単結合又は炭素数１〜１５の２価の飽和炭化水素基を表す。
Ｌ^b7は、炭素数１〜１５の２価の飽和炭化水素基を表す。但しＬ^b6及びＬ^b7の合計炭素数の上限は１６である。
Ｌ^b8は、炭素数１〜１４の２価の飽和炭化水素基を表す。
Ｌ^b9は、単結合又は炭素数１〜１１の２価の飽和炭化水素基を表す。
Ｌ^b10は、炭素数１〜１２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。
Ｌ^b11は、単結合又は炭素数１〜１３の２価の飽和炭化水素基を表す。
Ｌ^b12は、炭素数１〜１４の２価の飽和炭化水素基を表す。但しＬ^b11及びＬ^b12の合計炭素数の上限は１４である。

In formula (b1-1) to formula (b1-7),
L ^b2 represents a single bond or a divalent saturated hydrocarbon group having 1 to 15 carbon atoms.
L ^b3 represents a single bond or a divalent saturated hydrocarbon group having 1 to 12 carbon atoms.
L ^b4 represents a divalent saturated hydrocarbon group having 1 to 13 carbon atoms. However, the upper limit of the total carbon number of L ^b3 and L ^b4 is 13.
L ^b5 represents a divalent saturated hydrocarbon group having 1 to 15 carbon atoms.
L ^b6 represents a single bond or a divalent saturated hydrocarbon group having 1 to 15 carbon atoms.
L ^b7 represents a divalent saturated hydrocarbon group having 1 to 15 carbon atoms. However, the upper limit of the total carbon number of L ^b6 and L ^b7 is 16.
L ^b8 represents a divalent saturated hydrocarbon group having 1 to 14 carbon atoms.
L ^b9 represents a single bond or a divalent saturated hydrocarbon group having 1 to 11 carbon atoms.
L ^b10 represents a divalent saturated hydrocarbon group having 1 to 12 carbon atoms. However, the upper limit of the total carbon number of L ^b9 and L ^b10 is 12.
L ^b11 represents a single bond or a divalent saturated hydrocarbon group having 1 to 13 carbon atoms.
L ^b12 represents a divalent saturated hydrocarbon group having 1 to 14 carbon atoms. However, the upper limit of the total carbon number of L ^b11 and L ^b12 is 14.

Among them, L ¹ is preferably a divalent group represented by the formula (b1-1), and L ^b2 is represented by the formula (b1-1), which is a single bond or a saturated hydrocarbon group having 1 to 6 carbon atoms. Divalent group, that is, * —CO—O— (CH ₂ ) _u — (u represents an integer of 0 to 6, and * represents a bond to —C (Q ¹ ) (Q ² ) —. It is more preferable that the divalent group represented by the formula (b1-1) which is a single bond or a methylene group, that is, * —CO—O— or * —CO—O—CH ₂ — is more preferable. .

Examples of the divalent group represented by the formula (b1-1) include the following.

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

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

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

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

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

Examples of the divalent group represented by the formula (b1-7) include the following.

The alkyl group for R ¹ is preferably a methyl group.
In particular, when two R ¹ are present (that is, when s is 2), they may be alkyl groups independently of each other, or when the two R ¹ are bonded to the same carbon atom, 2 One R ¹ together with the carbon atom may form a carbonyl group. When three R ¹ are present (that is, when s is 3), they may be alkyl groups independently of each other, and if two R ^{1 of them} are bonded to the same carbon atom, The two R ^{1 s} may form a carbonyl group with the carbon atom, and the remaining one R ¹ may be an alkyl group. In addition, two or more R ¹ may be bonded to the same carbon atom, and may be an alkyl group independently of each other.

Examples of the sulfonate anion constituting the salt (I) include the following.

Examples of the organic counter ion represented by Z ⁺ include organic onium cations such as organic sulfonium cation, organic iodonium cation, organic ammonium cation, organic benzothiazolium cation, and organic phosphonium cation. Among these, an organic sulfonium cation and an organic iodonium cation are preferable, and an organic arylsulfonium cation is more preferable.

As the organic counter ion represented by Z ⁺ , an organic counter ion represented by any one of the following formulas (b2-1) to (b2-4) [hereinafter referred to as “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 each independently represent an alkyl 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, The hydrogen atom contained in the alkyl 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 is included in the alicyclic hydrocarbon group. The hydrogen atom 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 is a halogen atom, a hydroxy group, or a carbon number of 1 It may be substituted with an aliphatic hydrocarbon group having 18 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. Two ^members selected from R ^b4 , R ^b5 and R ^b6 may be combined to form a ring containing a sulfur atom.

The ring which may be formed by combining two selected from R ^b4 , R ^b5 and R ^b6 is any of monocyclic, polycyclic, aromatic, non-aromatic, saturated and unsaturated. It may be a ring and may contain one or more sulfur atoms and / or one or more oxygen atoms as long as it contains one or more sulfur atoms. As the ring, a ring having 3 to 18 carbon atoms is preferable, and a ring having 4 to 13 carbon atoms is more preferable.

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

R ^b9 and R ^b10 each independently represent an alkyl 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 alkyl 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 to} R ^b11 each independently represents an alkyl having 1 to 18 carbon atoms or an alicyclic hydrocarbon group having 3 to 18 carbon atoms. As for carbon number of this alkyl group, 1-12 are preferable. As for carbon number of this alicyclic hydrocarbon group, 4-12 are preferable.
R ^b12 represents an alkyl group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms, and hydrogen contained in the aromatic hydrocarbon group The atom may be substituted with 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 18 carbon atoms, or an alkylcarbonyloxy group having 1 to 12 carbon atoms. Good.
R ^b9 and R ^b10 and / or R ^b11 and R ^b12 are independently bonded to each other and together with the atoms to which they are bonded, a 3- to 12-membered ring (preferably a 3- to 7-membered ring) The methylene group contained in these rings may be replaced with an oxygen atom, a sulfur atom or a carbonyl group.

R ^{b13 to} R ^b18 each independently represent a hydroxy group, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group 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 When it is 2 or more, 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 include methylcarbonyloxy group, ethylcarbonyloxy group, n-propylcarbonyloxy group, isopropylcarbonyloxy group, n-butylcarbonyloxy group, sec-butylcarbonyloxy group, tert-butylcarbonyloxy group. Group, pentylcarbonyloxy group, hexylcarbonyloxy group, octylcarbonyloxy group, 2-ethylhexylcarbonyloxy group and the like.

Preferred alkyl groups are methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, hexyl, octyl and 2-ethylhexyl.
Preferred alicyclic hydrocarbon groups are 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.
Preferred aromatic hydrocarbon groups are phenyl group, 4-methylphenyl group, 4-ethylphenyl group, 4-tert-butylphenyl group, 4-cyclohexylphenyl group, 4-methoxyphenyl group, biphenylyl group and naphthyl group. It is.
Examples of the alkyl group in which a hydrogen atom is substituted with an aromatic hydrocarbon group include an aralkyl group such as a benzyl group.

Examples of the ring formed by combining R ^b9 and R ^b10 together with the sulfur atom to which they are bonded include, for example, a thiolane-1-ium ring (tetrahydrothiophenium ring), a thian-1-ium ring, and 1, 4-oxathian-4-ium ring etc. are mentioned.
Examples of the ring formed by combining R ^b11 and R ^b12 together with the carbon atoms of the methine group and carbonyl group to which they are bonded include, for example, oxocycloheptane ring, oxocyclohexane ring, oxonorbornane ring, and oxoadamantane ring Etc.

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のアルキル基、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し、Ｒ^b19、Ｒ^b20及びＲ^b21から選ばれる２つが一緒になって単結合、−Ｏ−又は炭素数１〜４の２価の脂肪族炭化水素基を表し、イオウ原子を含む環を形成してもよい。
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もよい。 Specific examples of the organic counter ion represented by each of formula (b2-1) to formula (b2-4) include cations described in JP 2010-204646 A.
Among the organic counter ions described above, cation (b2-1) is preferable, and organic counter ion represented by the following formula (b2-1-1) [hereinafter referred to as “cation (b2-1-1)” in some cases. ], 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 ^b19 , R ^b20 and R ^b21 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 alkyl group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or carbon. ^Represents an alkoxy group of 1 to 12, and two selected from R ^b19 , R ^b20 and R ^b21 together represent a single bond, —O— or a divalent aliphatic hydrocarbon group of 1 to 4 carbon atoms. A ring containing a sulfur atom may be formed.
v2, w2 and x2 each independently represent an integer of 0 to 5 (preferably 0 or 1).
When v2 is 2 or more, a plurality of R ^b19 may be the same or different, and when w2 is 2 or more, a plurality of R ^b20 may be the same or different. When x2 is 2 or more, a plurality of R ^{b19 b21} may be the same as or different from each other.

In formula (b2-1-1), the alkyl group preferably has 1 to 12 carbon atoms, and the hydrogen atom contained in the alkyl group has a hydroxy group, an alkoxy group having 1 to 12 carbon atoms, or a carbon atom having 6 to 18 carbon atoms. It may be substituted with an aromatic hydrocarbon group.
The alicyclic hydrocarbon group preferably has 4 to 18 carbon atoms, and the hydrogen atom contained in the alicyclic hydrocarbon group is substituted with a halogen atom, an acyl group having 2 to 4 carbon atoms or a glycidyloxy group. It may be.
Among them, R ^b19 , R ^b20 and R ^b21 are preferably each independently 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. It is.

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

The following are mentioned as a specific example of the cation in which the ring containing a sulfur atom was formed among cations (b2-1-1).

The following are mentioned as a specific example of the cation in which the ring containing a sulfur atom was formed among cations (b2-1).

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

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

Salt (I) is a combination of a sulfonate anion and an organic counter ion. These sulfonate anions and organic counter ions can be arbitrarily combined.
Examples of the salt (I) include salts described in Table 1 and Table 2 below.

Of these, the salts shown below are preferred.

（式中、Ｑ^１、Ｑ^２、Ｒ^１、ｓ及びＺ^１＋は、それぞれ上記と同じ意味を表す。） Among the salts represented by the formula (I), the salt represented by the formula (b1) (X ¹ in the formula (I) is * -CO-(* is -C (R ³ ) (R ⁴ )- The production method of the salt) is shown below.

(In the formula, Q ¹ , Q ² , R ¹ , s and Z ¹⁺ each have the same meaning as described above.)

First, the salt represented by the formula (b1-c) is obtained by reacting the salt represented by the formula (b1-a) with the compound represented by the formula (b1-b).
The salt represented by the formula (b1-a) can be synthesized, for example, by the method described in JP2008-13551A.

式（ｂ１−ｄ）で表される化合物としては、以下で表される化合物等が挙げられる。

The salt represented by the formula (b1) can be obtained by reacting the obtained salt represented by the formula (b1-c) and the compound represented by the formula (b1-d) in a solvent. it can.
Examples of the solvent here include acetonitrile.

Examples of the compound represented by the formula (b1-d) include compounds represented by the following.

<Acid generator>
The acid generator of the present invention contains a salt (I). When the salt (I) is used as an acid generator, it may be used alone or in combination. In addition, the acid generator of the present invention is a salt other than the salt (I) known as an acid generator (for example, an organic counter ion contained in the salt (I) and a known anion (included in the salt (I)). And a sulfonate anion contained in the salt (I) and a known cation (a salt comprising a cation other than the organic counter ion contained in the salt (I)). Also good. Hereinafter, salts other than the salt (I) contained in the acid generator of the present invention are sometimes referred to as “acid generator (B)”.

  Examples of the acid generator (B) used in combination with the salt (I) include salts represented by formulas (B1-1) to (B1-17), respectively. Among them, those containing a triphenylsulfonium cation and a tolylsulfonium cation are preferable. Formula (B1-1), Formula (B1-2), Formula (B1-3), Formula (B1-6), and Formula (B1-7) And salts represented by formula (B1-11), formula (B1-12), formula (B1-13) and formula (B1-14), respectively.

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

<Resist composition>
The resist composition of the present invention contains the acid generator of the present invention and a resin (hereinafter referred to as “resin (A)”).

<Resin (A)>
The resin (A) is a resin having an acid labile group and insoluble or hardly soluble in an alkaline aqueous solution, and can be dissolved in an alkaline aqueous solution by the action of an acid. “Becomes soluble in an alkaline aqueous solution by the action of an acid” means insoluble or hardly soluble in an alkaline aqueous solution before contact with an acid, but becomes soluble in an alkaline aqueous solution after contact with an acid. .
In such a resin (A), a part or all of the hydrophilic group in the molecule is protected by a protecting group that can be removed by contact with an acid, and the resin (A) is in contact with an acid. Then, the protecting group is eliminated and a hydrophilic group is generated, so that the resin (A) becomes a resin soluble in an alkaline aqueous solution. The hydrophilic group protected by the protecting group is hereinafter sometimes referred to as “acid labile group”. Examples of the hydrophilic group include a hydroxy group or a carboxy group, and a carboxy group is more preferable.

<Monomer (a1)>
The resin (A) can be produced by polymerizing a monomer having an acid labile group (hereinafter sometimes referred to as “monomer (a1)”). In the polymerization, only one type of monomer (a1) may be used, or two or more types may be used in combination.

式（１）中、
Ｒ^a1〜Ｒ^a3は、それぞれ独立に、炭素数１〜８のアルキル基又は炭素数３〜２０の脂環式炭化水素基を表すか、或いは、Ｒ^a1及びＲ^a2は互いに結合して、それらが結合する炭素原子とともに炭素数３〜２０の環を形成する。Ｒ^a1及びＲ^a2が互いに結合して形成される環、該アルキル基又は該脂環式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。 The acid labile group in the case where the hydrophilic group is a carboxy group is such that the hydrogen atom of the carboxy group is replaced with an organic residue, and the carbon atom of the organic residue bonded to the oxy group is a tertiary carbon atom. Groups (ie esters of tertiary alcohols). Among such acid labile groups, preferred acid labile groups are, for example, those represented by the following formula (1) (hereinafter sometimes referred to as “acid labile groups (1)”).

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

なかでも、このような環は、好ましくは炭素数３〜１２である。 In Formula (1), the alicyclic hydrocarbon group of R ^{a1 to} R ^a3 preferably has 1 to 16 carbon atoms.
When R ^a1 and R ^a2 are bonded to each other to form a ring, examples of the —C (R ^a1 ) (R ^a2 ) (R ^a3 ) group include those shown below.

Among them, such a ring preferably has 3 to 12 carbon atoms.

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

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は互いに結合して、それらが各々結合する炭素原子及び酸素原子とともに炭素数３〜２０の環を形成する。Ｒ^b2及びＲ^b3は互いに結合して形成される環又は該炭化水素基を構成しているメチレン基は、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。 In the case where the hydrophilic group is a hydroxy group, examples of the acid labile group include those in which a hydrogen atom of the hydroxy group is replaced with an organic residue and a group containing an acetal structure or a ketal structure is obtained. Among such acid labile groups, preferred acid labile groups are, for example, those represented by the following formula (2) (hereinafter sometimes referred to as “acid labile groups (2)”).

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

In formula (2), at least one of R ^b1 and R ^b2 is preferably a hydrogen atom.
^Examples of the ring formed by combining R ^b2 and R ^b3 include those in which one carbon atom of the ring formed by combining R ^a1 and R ^a2 described above is replaced with one oxygen atom.

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

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

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

  Among the (meth) acrylic monomers having an acid labile group (1), those having an acid labile group (1) having an aliphatic ring having 5 to 20 carbon atoms are preferred. If a resist pattern is produced using a resist composition containing the resin (A) obtained by polymerizing the monomer (a1) having such a sterically bulky aliphatic ring, a better focus margin (DOF) A resist pattern can be manufactured.

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

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

In the formula (a1-1) and the formula (a1-2), L ^a1 and L ^a2 are preferably an oxygen atom or * —O— (CH ₂ ) _f1 —CO—O— (where f1 is 1 to 1). Represents an integer of 4, and * represents a bond to a carbonyl group (—CO—). More preferably, it is an oxygen atom. f1 is more preferably 1.
R ^a4 and R ^a5 are preferably methyl groups.
As the aliphatic hydrocarbon group for R ^a6 and R ^a7 , 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 are preferable. These alkyl groups are preferably groups having 6 or less carbon atoms. The alicyclic hydrocarbon group for R ^a6 or R ^a7 preferably has 8 or less carbon atoms, more preferably 6 or less.
m1 is preferably an integer of 0 to 3, more preferably 0 or 1.
n1 is preferably an integer of 0 to 3, more preferably 0 or 1.
* Represents a bond with an adamantane ring or a cyclohexane ring.

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

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

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

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

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

  Examples of the alkyl group that may have a hydroxy group include a methyl group, an ethyl group, a propyl group, a hydroxymethyl group, and a 2-hydroxyethyl group.

In formula (a1-3), R ^a9 is preferably a hydrogen atom.
The ring formed by combining R ^a10 and R ^a11 is preferably an aliphatic ring, and specifically, a cyclohexane ring and an adamantane ring are more preferable.

  As the monomer (a1-3), 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 And the like.

  When the resin (A) is produced using the monomer (a1-3), the resin (A) is derived from the monomer (a1-3) and includes a three-dimensionally bulky structural unit. A resist pattern can be obtained with a better focus margin (DOF) by producing a resist pattern using a resist composition containing the resin (A) having this structural unit. Furthermore, since a rigid norbornane ring can be introduced into the main chain of the resin (A) by using the monomer (a1-3), the resist pattern obtained from the resist composition containing the resin (A) has excellent dry etching resistance. The resist pattern tends to be easily obtained.

  From the viewpoint that a resist pattern can be produced with a good focus margin (DOF) and a resist pattern excellent in dry etching resistance can be easily obtained, the monomer (a1-3) relative to all the structural units (100 mol%) of the resin (A) ) -Derived structural unit content is preferably in the range of 10 to 95 mol%, more preferably in the range of 15 to 90 mol%, still more preferably in the range of 20 to 85 mol%.

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

In formula (a1-4),
R ^a32 represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom.
R ^a33 is a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an acyl group having 2 to 4 carbon atoms, an acyloxy group having 2 to 4 carbon atoms, an acryloyl group, or methacryloyl. Represents a group.
la represents an integer of 0 to 4. When la is 2 or more, the plurality of R ^a33 may be the same as or different from each other.
R ^a34 and R ^a35 each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms.
X ^a2 represents a single bond or a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group is a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, The methylene group which may be substituted with a C1-C6 alkoxy group, a C2-C4 acyl group, or a C2-C4 acyloxy group is a carbonyl group. , An oxygen atom, a sulfur atom, a sulfonyl group (—SO ₂ —) or a group represented by —N (R ^c ) — may be substituted. Here, R ^c represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
Y ^a3 represents an alkyl group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms, and the alkyl group or the alicyclic hydrocarbon group. Group and each aromatic hydrocarbon group include a hydrogen atom, a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an acyl group having 2 to 4 carbon atoms, or It may be substituted with an acyloxy group having 2 to 4 carbon atoms.

  Examples of the alkyl group which may have a halogen atom include a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group, a perfluorotert-butyl group, and a perfluoropentyl group. Group, perfluorohexyl group, trichloromethyl group, tribromomethyl group, triiodomethyl group and the like.

  In the formula (a1-4), the alkyl group is preferably an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, an octyl group or a 2-ethylhexyl group. As the alicyclic hydrocarbon group, a cyclohexyl group, an adamantyl group, a 2-alkyladamantan-2-yl group, a 1- (adamantan-1-yl) alkane-1-yl group, an isobornyl group, and the like are preferable. Aromatic hydrocarbon groups include phenyl, naphthyl, anthryl, p-methylphenyl, p-tert-butylphenyl, p-adamantylphenyl, tolyl, xylyl, cumenyl, mesityl, biphenyl Group, phenanthryl group, 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl and the like are preferable.

In particular, R ^a32 and R ^a33 are preferably an alkyl group having 1 to 4 carbon atoms, more preferably a methyl group or an ethyl group, and particularly preferably a methyl group.
R ^a33 is more preferably a methoxy group or an ethoxy group, and particularly preferably a methoxy group.
The R ^a34 and R ^a35, isopropyl group, n- butyl group, sec- butyl group, tert- butyl group, a pentyl group, a hexyl group, an octyl group, a 2-ethylhexyl group, a cyclohexyl group, an adamantyl group, 2-alkyl-adamantane A 2-yl group, a 1- (adamantan-1-yl) alkane-1-yl group, an isobornyl group, and the like are preferable.
The substituent for X ^a2 and Y ^a3 is preferably a hydroxy group.

Examples of the monomer (a1-4) include the following monomers.

  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.

Furthermore, a monomer that derives another structural unit having an acid labile group (1) and a carbon-carbon double bond in the molecule may be used.
Examples of such other acid labile monomers include the following monomers.

  When the resin (A) has a structural unit derived from another acid labile monomer, the content is preferably 10 to 95 mol% with respect to the total structural unit (100 mol%) of the resin (A). More preferably, it is 15-90 mol%, More preferably, it is 20-85 mol%.

<Acid stable monomer>
As the resin (A) used in the resist composition of the present invention, a copolymer obtained by using a monomer having no acid labile group (hereinafter sometimes referred to as “acid-stable monomer”) in addition to the monomer (a1). A polymer is preferred. Moreover, you may use resin obtained from an acid stable monomer as an additive used for a resist composition.

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

As the acid stable monomer, those having a hydroxy group or a lactone ring in the molecule are preferable.
Derived from an acid-stable monomer having a hydroxy group (hereinafter sometimes referred to as “acid-stable monomer (a2)”) and / or an acid-stable monomer having a lactone ring (hereinafter sometimes referred to as “acid-stable monomer (a3)”) The resin (A) having a structural unit is a coating film formed on the substrate when the resist composition containing the resin (A) is applied to the substrate, or between the composition layer obtained from the coating film and the substrate. Excellent adhesion. In addition, a resist pattern can be manufactured with a good focus margin (DOF).

<Acid stable monomer (a2)>
When the acid-stable monomer (a2) is used for the production of the resin (A), a suitable acid-stable monomer (a2) is used depending on the type of exposure source when obtaining a resist pattern from the resist composition containing the resin (A). 1 type (s) or 2 or more types can be used.
For example, when the resist composition is used for KrF excimer laser exposure (wavelength: 248 nm), high energy beam exposure such as electron beam or EUV light, the acid stable monomer having a phenolic hydroxy group is used as the acid stable monomer (a2). It is preferable to use the monomer (a2-0) [for example, hydroxystyrenes] for the production of the resin (A).
On the other hand, when short-wave ArF excimer laser exposure (wavelength: 193 nm) is used, an acid-stable monomer represented by the formula (a2-1) described later is used as the acid-stable monomer (a2) in the production of the resin (A). It is preferable to use it.

式（ａ２−０）中、
Ｒ^a30は、水素原子、ハロゲン原子又はハロゲン原子を有してもよい炭素数１〜６のアルキル基を表す。
Ｒ^a31は、ハロゲン原子、ヒドロキシ基、炭素数１〜６のアルキル基、炭素数１〜６のアルコキシ基、炭素数２〜４のアシル基、炭素数２〜４のアシルオキシ基、アクリロイル基又はメタクリロイル基を表す。
ｍａは０〜４の整数を表す。ｍａが２以上の整数である場合、複数のＲ^a31は互いに同一であっても異なってもよい。 Examples of the acid stable monomer (a2) include styrene monomers such as p- or m-hydroxystyrene represented by the formula (a2-0) (hereinafter sometimes referred to as “acid stable monomer (a2-0)”). It is done.

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

In the formula (a2-0), the alkyl group which may have a halogen atom is preferably an alkyl group having 1 to 4 carbon atoms, more preferably a methyl group or an ethyl group, and further preferably a methyl group.
As an alkoxy group, a C1-C4 alkoxy group is preferable, a methoxy group or an ethoxy group is more preferable, and a methoxy group is further more preferable.
ma is preferably 0, 1 or 2, more preferably 0 or 1, and still more preferably 0.

  A copolymer resin having a structural unit derived from such an acid-stable monomer (a2-0) is obtained by radical polymerization of the corresponding (meth) acrylic acid ester monomer, acetoxystyrene, and / or other polymerizable monomer, It can be obtained by deacetylation with a base.

As an acid stable monomer (a2-0), the monomer described in Unexamined-Japanese-Patent No. 2010-204634 is mentioned, for example. Of these, monomers represented by the formulas (a2-0-1) and (a2-0-2) are preferable. When manufacturing resin (A), you may use what protected the phenolic hydroxy group in these with a suitable 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). Is preferable, the range of 10 to 80 mol% is more preferable, and the range of 15 to 80 mol% is more preferable.

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

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

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

As an acid stable monomer (a2-1), the monomer described in Unexamined-Japanese-Patent No. 2010-204646 is mentioned, for example. Among these, monomers represented by formulas (a2-1-1) to (a2-1-6) are preferable, respectively, and represented by formulas (a2-1-1) to (a2-1-4), respectively. The monomer represented by the formula (a2-1-1) or the formula (a2-1-3) is more preferable.

  When the resin (A) has a structural unit derived from the acid-stable monomer (a2-1), the content is 3 to 45 mol% with respect to the total structural unit (100 mol%) of the resin (A). The range of 5 to 40 mol% is more preferable, the range of 5 to 35 mol% is more preferable, the range of 5 to 20 mol% is further preferable.

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

式（ａ３−１）中、
Ｌ^a4は、酸素原子又は＊−Ｏ−（ＣＨ₂）_k3−ＣＯ−Ｏ−を表す。
ｋ３は１〜７の整数を表す。＊は−ＣＯ−との結合手を表す。
Ｒ^a18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の整数を表す。
ｐ１が２以上のとき、それぞれ、複数のＲ^a21は、互いに同一であっても異なってもよい。 The acid stable monomer (a3) is preferably represented by the following formula (a3-1). In manufacture of resin (A), only 1 type may be used among these and 2 or more types may be used together. In the following description, the acid stable monomer (a3) represented by the formula (a3-1) may be referred to as “acid stable monomer (a3-1)”.

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 -CO-.
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.
When p1 is 2 or more, the plurality of R ^a21 may be the same as or different from each other.

In Formula (a3-1), L ^a4 is preferably an oxygen atom or * —O— (CH ₂ ) _d1 —CO—O— (where d1 is an integer of 1 to 4), and more Preferably it is an oxygen atom.
R ^a18 and R ^a21 are each independently preferably a methyl group.
p1 is preferably an integer of 0 to 2, more preferably 0 or 1.

As an acid stable monomer (a3-1), the monomer described in Unexamined-Japanese-Patent No. 2010-204646 is mentioned. Among these, monomers represented by formulas (a3-1-1) to (a3-1-4) are preferable, respectively, and represented by formulas (a3-1-1) to (a3-1-2), respectively. The monomer represented by the formula (a3-1-1) is more preferable.

  When the resin (A) has a structural unit derived from the monomer (a3-1), the content thereof is in the range of 5 to 70 mol% with respect to all the structural units (100 mol%) of the resin (A). Is preferable, the range of 10 to 65 mol% is more preferable, and the range of 10 to 60 mol% is more preferable.

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

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

  In formula (a4-3), the alkyl group is preferably a group having 1 to 8 carbon atoms, more preferably a group having 1 to 6 carbon atoms. The alicyclic hydrocarbon group is preferably a group having 4 to 18 carbon atoms, more preferably a group having 4 to 12 carbon atoms.

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

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

Further, as the acid stable monomer (a4), for example, a monomer having a fluorine atom as shown below (hereinafter sometimes referred to as “monomer (a4-4)”) may be used.

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

  When the resin (A) has a structural unit derived from the monomer (a4-4), the total content thereof is 1 to 20 mol% with respect to all the structural units (100 mol%) of the resin (A). The range is preferable, the range of 2 to 15 mol% is more preferable, and the range of 3 to 10 mol% is more preferable.

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

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

<Basic compound (hereinafter sometimes referred to as “basic compound (C)”)>
The resist composition of the present invention preferably further contains a basic compound (C). The “basic compound” means a compound having a property of capturing an acid (hereinafter, sometimes referred to as “quencher”), particularly a compound having a property of capturing an acid generated from an acid generator.

式（Ｃ２）及び式（Ｃ２−１）中、
Ａｒ^c1は、芳香族炭化水素基を表す。
Ｒ^c5及びＲ^c6は、それぞれ独立に、水素原子、アルキル基、脂環式炭化水素基又は芳香族炭化水素基を表す。
Ｒ^c7は、アルキル基、アルコキシ基、脂環式炭化水素基、芳香族炭化水素基又はニトロ基を表す。
これらアルキル基、アルコキシ基、脂環式炭化水素基及び芳香族炭化水素基にある水素原子は、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もよい。 The basic compound (C) is preferably a basic nitrogen-containing organic compound, and examples thereof include amines and ammonium salts. The amine may be an aliphatic amine or an aromatic amine. The aliphatic amine may be any of primary amine, secondary amine and tertiary amine. The aromatic amine may be either an aromatic ring such as aniline bonded with an amino group or a heteroaromatic amine such as pyridine. Preferred basic compounds (C) include aromatic amines represented by the following formula (C2), and more preferred basic compounds (C) include anilines represented by the following formula (C2-1). .

In formula (C2) and formula (C2-1),
Ar ^c1 represents an aromatic hydrocarbon group.
R ^c5 and R ^c6 each independently represent a hydrogen atom, an alkyl group, an alicyclic hydrocarbon group, or an aromatic hydrocarbon group.
R ^c7 represents an alkyl group, an alkoxy group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, or a nitro group.
The hydrogen atom in these alkyl group, alkoxy group, alicyclic hydrocarbon group and aromatic hydrocarbon group may be substituted with a hydroxy group, an amino group or an alkoxy group having 1 to 6 carbon atoms. 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.

In formula (C2) and formula (C2-1),
The alkyl group and the alkoxy group preferably have 1 to 6 carbon atoms.
The alicyclic hydrocarbon group preferably has 5 to 10 carbon atoms, and more preferably a cycloalkyl group having 5 to 10 carbon atoms.
The aromatic hydrocarbon group preferably has 6 to 10 carbon atoms.

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

式（Ｃ３）〜式（Ｃ１１）中、
Ｒ^c8、Ｒ^c20、Ｒ^c21、Ｒ^c23、Ｒ^c24、Ｒ^c25、Ｒ^c26、Ｒ^c27及びＲ^c28は、互いに独立に、Ｒ^c7で説明したいずれかの基を表す。
Ｒ^c9、Ｒ^c10、Ｒ^c11、Ｒ^c12、Ｒ^c13、Ｒ^c14、Ｒ^c16、Ｒ^c17、Ｒ^c18、Ｒ^c19及びＲ^c22は、互いに同一でも異なってもよく、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もよく、ｐ３が２以上であるとき、複数のＲ^c21は互いに同一でも異なってもよく、ｑ３が２以上であるとき、複数のＲ^c24は互いに同一でも異なってもよく、ｒ３が２以上であるとき、複数のＲ^c25は互いに同一でも異なってもよく、ｓ３が２以上であるとき、複数のＲ^c26は互いに同一でも異なってもよく、ｔ３が２以上であるとき、複数のＲ^c27は互いに同一でも異なってもよく、ｕ３が２以上であるとき、複数のＲ^c28は互いに同一でも異なってもよい。
Ｒ^c15は、アルキル基（好ましくは、炭素数１〜６のアルキル基である）、脂環式炭化水素基（好ましくは、炭素数３〜６の脂環式炭化水素基である）又はアルカノイル基（好ましくは、炭素数２〜６のアルカノイル基である）を表す。
ｎ３は０〜８の整数を表す。ｎ３が２以上のとき、複数のＲ^c15は、互いに同一でも異なってもよい。
Ｌ^c1及びＬ^c2は、それぞれ独立に、アルカンジイル基（好ましくは、炭素数１〜６のアルキレン基である）、カルボニル基、−Ｃ（＝ＮＨ）−、−Ｃ（＝ＮＲ^c3）−（但し、Ｒ^c3は、炭素数１〜４のアルキル基を表す）、チオキシ基、ジスルフィド結合（−Ｓ−Ｓ−）又はこれらの組合せを表す。 A compound represented by any of the following formulas (C3) to (C11) (hereinafter referred to as “compound (C3)” to “compound (C11)” depending on the formula number) can also be used.

In formula (C3) to formula (C11),
R ^c8 , R ^c20 , R ^c21 , R ^c23 , R ^c24 , R ^c25 , R ^c26 , R ^c27 and R ^c28 each independently represent any group described for R ^c7 .
R ^c9 , R ^c10 , R ^c11 , R ^c12 , R ^c13 , R ^c14 , R ^c16 , R ^c17 , R ^c18 , R ^c19 and R ^c22 may be the same as or different from each other, and R ^c5 and R ^c6 Represents any of the groups described.
o3, p3, q3, r3, s3, t3 and u3 each independently represents an integer of 0 to 3. When o3 is 2 or more, the plurality of R ^c20 may be the same or different from each other. When p3 is 2 or more, the plurality of R ^c21 may be the same or different from each other, and when q3 is 2 or more, multiple R ^c24 may be the same or different from each other, when r3 is 2 or more, plural R ^c25 may be the same or different from each other, when s3 is 2 or more, even the plurality of R ^{c 26} identical to one another When t3 is 2 or more, the plurality of R ^c27 may be the same as or different from each other. When ^u3 is 2 or more, the plurality of R ^c28 may be the same or different from each other.
R ^c15 is an alkyl group (preferably an alkyl group having 1 to 6 carbon atoms), an alicyclic hydrocarbon group (preferably an alicyclic hydrocarbon group having 3 to 6 carbon atoms) or an alkanoyl group. (Preferably an alkanoyl group having 2 to 6 carbon atoms).
n3 represents an integer of 0 to 8. When n3 is 2 or more, the plurality of R ^c15 may be the same as or different from each other.
L ^c1 and L ^c2 each independently represent an alkanediyl group (preferably an alkylene group having 1 to 6 carbon atoms), a carbonyl group, —C (═NH) —, —C (═NR ^c3 ) — ( R ^c3 represents an alkyl group having 1 to 4 carbon atoms), a thioxy group, a disulfide bond (—S—S—), or a combination thereof.

  Examples of the alkanoyl group include acetyl group, 2-methylacetyl group, 2,2-dimethylacetyl group, propionyl group, butyryl group, isobutyryl group, pentanoyl group, and 2,2-dimethylpropionyl group.

In Formula (C3) to Formula (C11), the alkyl group preferably has 1 to 6 carbon atoms. The alicyclic hydrocarbon group preferably has 3 to 6 carbon atoms. The alkanoyl group preferably has 2 to 6 carbon atoms.
The alkanediyl group is preferably an alkanediyl group having 1 to 6 carbon atoms.

  Examples of the basic compound (C3) include hexylamine, heptylamine, octylamine, nonylamine, decylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, triethylamine, trimethylamine, tripropyl Amine, tributylamine, tripentylamine, trihexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, methyldibutylamine, methyldipentylamine, methyldihexylamine, methyldicyclohexylamine, methyldiheptylamine, Methyldioctylamine, methyldinonylamine, methyldidecylamine, ethyldibutylamine, ethyldipentylamine, ethyl Dihexylamine, ethyldiheptylamine, ethyldioctylamine, ethyldinonylamine, ethyldidecylamine, dicyclohexylmethylamine, tris [2- (2-methoxyethoxy) ethyl] amine, triisopropanolamine, ethylenediamine, tetramethylenediamine, Hexamethylenediamine, 4,4′-diamino-1,2-diphenylethane, 4,4′-diamino-3,3′-dimethyldiphenylmethane, 4,4′-diamino-3,3′-diethyldiphenylmethane, etc. are also used. be able to.

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

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

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

<Solvent (hereinafter referred to as “solvent (D)” in some cases)>
The resist composition of the present invention preferably contains a solvent (D). The solvent (D) depends on the type and amount of the salt (I) to be used, the type and amount of the resin (A), the type and amount of the acid generator (B), and the resist pattern production method described later. In consideration of applicability when applying the resist composition on the substrate, it can be appropriately selected.

  As the solvent (D), glycol ether esters such as ethyl cellosolve acetate, methyl cellosolve acetate and propylene glycol monomethyl ether acetate; glycol ethers such as propylene glycol monomethyl ether; ethyl lactate, butyl acetate, amyl acetate and ethyl pyruvate Esters; ketones such as acetone, methyl isobutyl ketone, 2-heptanone and cyclohexanone; 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 components (hereinafter sometimes referred to as “component (F)”)>
If necessary, the resist composition of the present invention comprises a salt (I), a resin (A), and a solvent (D), an acid generator (B), and a basic compound (C) other than those used as necessary. The component (F) may be included. Examples of the component (F) include additives known in the art, for example, polymer compounds other than the resin (A), sensitizers, dissolution inhibitors, surfactants, stabilizers, and dyes.

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

  The content of the solvent (D) is preferably 90% by mass or more, more preferably 92% by mass or more, still more preferably 94% by mass or more, and 99.9% by mass or less, based on the total mass of the resist composition. Is more preferable, and 99 mass% or less is more preferable. With such a content, the resist composition containing the solvent (D) easily forms a composition layer having a thickness of about 30 to 300 nm, for example, in a method for producing a resist pattern described later.

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

  Content of salt (I) becomes like this. Preferably it is 1 mass part or more with respect to 100 mass parts of resin (A) contained in a resist composition, More preferably, it is 3 mass parts or more. Moreover, Preferably it is 30 mass parts or less, More preferably, it is 25 mass parts or less.

  When the acid generator (B) is used in the resist composition, the total content of the salt (I) and the acid generator (B) is preferably based on 100 parts by mass of the resin (A) contained in the resist composition. Is 1 part by mass or more, more preferably 3 parts by mass or more. Moreover, Preferably it is 30 mass parts or less, More preferably, it is 25 mass parts or less.

When the basic compound (C) is used in the resist composition, the content thereof is preferably about 0.01 to 1% by mass with respect to the total mass of the solid content of the resist composition. In addition, it is preferable that content of a basic compound (C) is lower than the total content of salt (I) and an acid generator (B).
It can be obtained by using a known analysis means such as liquid chromatography.

In addition, when using a component (F) for this resist composition, suitable content can be adjusted according to the kind of component (F).
Thus, after mixing each component with preferable content, a resist composition can be prepared by filtering using a filter with a hole diameter of about 0.01-0.2 micrometer.

<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 of the present invention on a substrate,
(2) The process of drying the composition after application | coating and forming a composition layer,
(3) a step of exposing the composition layer using an exposure machine;
(4) A step of heating the composition layer after exposure and (5) a step of developing the composition layer after heating.

  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. Thereby, the coating film which consists of a resist composition can be formed on a board | substrate. The film thickness of the coating film can be adjusted by variously adjusting the conditions (coating conditions) of the coating apparatus. By performing an appropriate preliminary experiment or the like, the coating conditions can be selected so that the coating film has a desired film thickness. Various substrates to be subjected to microfabrication can be selected as the substrate before applying the resist composition. Before applying the resist composition, the substrate may be washed to form an antireflection film. For example, a commercially available composition for an organic antireflection film can be used for forming the antireflection film.

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

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

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

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

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

<Application>
The resist composition of the present invention includes a resist composition for KrF excimer laser exposure, a resist composition for ArF excimer laser exposure, a resist composition for electron beam (EB) irradiation, or a resist composition for an EUV exposure machine, It is suitable as a resist composition for immersion exposure.

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

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

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

The salt represented by the formula (I1-a) was synthesized by the method described in JP 2008-127367 A.
5.00 parts of a salt represented by the formula (I1-a) and 25 parts of chloroform are charged, stirred at 30 ° C. for 30 minutes, and 1.83 parts of a compound represented by the formula (I1-b) are charged at 60 ° C. Was stirred for 1 hour to obtain a solution containing the compound represented by the formula (I1-c).

  To the obtained solution containing the compound represented by the formula (I1-c), 1.86 parts of the compound represented by the formula (I1-d) was charged and stirred at 23 ° C. for 3 hours. To the resulting reaction mass, 10 parts of ion-exchanged water was added, and stirring and liquid separation were performed. Water washing was performed 5 times. The obtained organic layer was charged with 1.00 parts of activated carbon, stirred at 23 ° C. for 30 minutes, and filtered. The filtrate was concentrated, 30 parts of tert-butyl methyl ether was added to the resulting concentrate and stirred, and the supernatant was removed. The resulting residue was dissolved in acetonitrile and concentrated. Thereafter, 20 parts of tert-butyl methyl ether was added to the resulting concentrate and stirred, and the supernatant was removed. The obtained residue was dissolved in chloroform and concentrated to obtain 2.24 parts of the salt represented by the formula (I1).

MS (ESI (+) Spectrum): M ⁺ 263.1
MS (ESI (-) Spectrum): M ^- 339.0

Example 2: Synthesis of a salt represented by the formula (I13)

  10.96 parts of a salt represented by the formula (I13-a) and 65.76 parts of acetonitrile are charged, stirred at 40 ° C. for 30 minutes, and 4.44 parts of a compound represented by the formula (I1-b) are charged. By stirring at 50 ° C. for 1 hour, a solution containing the compound represented by the formula (I13-b) was obtained.

  To the obtained solution containing the compound represented by the formula (I13-b), 4.16 parts of the compound represented by the formula (I1-d) was charged and stirred at 23 ° C. for 1 hour. To the obtained reaction mass, 100 parts of chloroform and 50 parts of ion-exchanged water were added, and the mixture was stirred and separated. Water washing was performed 5 times. The obtained organic layer was charged with 1.00 parts of activated carbon, stirred at 23 ° C. for 30 minutes, and filtered. After concentrating the filtrate, 50 parts of acetonitrile was added to dissolve the resulting concentrate, the mixture was concentrated, 50 parts of ethyl acetate was added and stirred, and the supernatant was removed. To the obtained residue, 50 parts of tert-butyl methyl ether was added and stirred, and the supernatant was removed. The obtained residue was dissolved in chloroform and concentrated to obtain 12.68 parts of the salt represented by the formula (I13).

MS (ESI (+) Spectrum): M ⁺ 305.1
MS (ESI (-) Spectrum): M ^- 339.0

Example 3: Synthesis of a salt represented by the formula (I69)

  50.00 parts of the compound represented by the formula (I69-a) and 250 parts of tetrahydrofuran were charged into a reactor, stirred at 30 ° C. for 30 minutes, and 50.23 parts of trimethylsilyl chloride was added dropwise. The obtained mixed liquid was cooled to 0 ° C., and 157.20 parts of a compound represented by the formula (I69-b) (purity: 32%, manufactured by Tokyo Chemical Industry Co., Ltd.) was added dropwise over 30 minutes, and the temperature was further raised to 23 ° C. And stirred at the same temperature for 1 hour. To the resulting reaction mixture, 125 parts of 1N hydrochloric acid was charged, stirred and allowed to stand, and separated to recover the aqueous layer. To the recovered aqueous layer, 125 parts of tert-butyl methyl ether was added, stirred and allowed to stand, and the aqueous layer was recovered by liquid separation. To the recovered aqueous layer, 125 parts of chloroform was added, stirred and allowed to stand, and separated to recover the organic layer. After the collected organic layer was filtered, the obtained filtrate was concentrated. The concentrated residue was charged with 28.33 parts of acetonitrile and 354.15 parts of tert-butyl methyl ether, stirred at 23 ° C. for 30 minutes, and the precipitated crystals were filtered to obtain a compound represented by the formula (I69-c). 53.00 parts were obtained.

まず、式（Ｉ６９−ｄ）で表される化合物を、特開２００６−２５７０７８号公報に記載された方法で合成した。式（Ｉ６９−ｄ）で表される化合物１３．１２部及びクロロホルム７３．８６部を、反応器中に仕込み、３０℃で３０分間攪拌し、式（Ｉ６９−ｃ）で表される塩２０．７１部及びイオン交換水６２．２７部を添加した。次いで、３５％塩酸６．９０部を滴下し、２３℃で１２時間攪拌した。得られた反応混合物に、２８％アンモニア水１２．００部を滴下し、分液することで有機層を回収した。回収された有機層に、イオン交換水５０部を仕込み、攪拌、静置及び分液といった水洗操作を計５回行った。得られた有機層に活性炭２．００部を仕込み、２３℃で３０分間攪拌し、ろ過した。ろ液を濃縮し、得られた濃縮物に、アセトニトリル３０部及びｔｅｒｔ−ブチルメチルエーテル１５０部を加えて攪拌し、ろ過することにより、式（Ｉ６９−ｅ）で表される塩１４．２８部を得た。

First, the compound represented by the formula (I69-d) was synthesized by the method described in JP-A-2006-257078. 13.12 parts of the compound represented by the formula (I69-d) and 73.86 parts of chloroform were charged into a reactor, stirred at 30 ° C. for 30 minutes, and the salt represented by the formula (I69-c) 20. 71 parts and 62.27 parts of ion exchange water were added. Subsequently, 6.90 parts of 35% hydrochloric acid was added dropwise and stirred at 23 ° C. for 12 hours. To the resulting reaction mixture, 12.00 parts of 28% aqueous ammonia was added dropwise and separated to recover the organic layer. The recovered organic layer was charged with 50 parts of ion-exchanged water and subjected to a total of five washing operations such as stirring, standing and liquid separation. The obtained organic layer was charged with 2.00 parts of activated carbon, stirred at 23 ° C. for 30 minutes, and filtered. The filtrate was concentrated, and 30 parts of acetonitrile and 150 parts of tert-butyl methyl ether were added to the resulting concentrate and stirred, followed by filtration to give 14.28 parts of the salt represented by the formula (I69-e). Got.

  10.32 parts of the salt represented by the formula (I69-e) and 61.91 parts of acetonitrile were charged, stirred at 40 ° C. for 30 minutes, and 4.44 parts of the compound represented by the formula (I1-b) were charged. . This was stirred at 50 ° C. for 1 hour to obtain a solution containing the compound represented by the formula (I69-f). To the obtained solution containing the compound represented by the formula (I69-f), 4.16 parts of the compound represented by the formula (I1-d) was charged and stirred at 50 ° C. for 3 hours. To the obtained reaction mass, 100 parts of chloroform and 50 parts of ion-exchanged water were added, and the mixture was stirred and separated. Water washing was performed 5 times. The obtained organic layer was charged with 1.00 parts of activated carbon, stirred at 23 ° C. for 30 minutes, and filtered. The filtrate was concentrated, and 50 parts of acetonitrile was added to the resulting concentrate to dissolve it, concentrated, 50 parts of ethyl acetate was added and stirred, and the supernatant was removed. To the obtained residue, 50 parts of tert-butyl methyl ether was added and stirred, and the supernatant was removed. The obtained residue was dissolved in chloroform and concentrated to obtain 9.96 parts of the compound represented by the formula (I69).

MS (ESI (+) Spectrum): M ⁺ 277.1
MS (ESI (-) Spectrum): M ^- 339.0

Synthesis Example 1 (Synthesis of Resin (A))
The compounds (monomers) used in the resin synthesis are shown below. Hereinafter, these monomers are referred to as “monomer (A)” to “monomer (F)”.

[Synthesis of Resin A1]
Monomer (D), monomer (E), monomer (B), monomer (C) and monomer (F) are mixed in a molar ratio [monomer (D): monomer (E): monomer (B): monomer (C): Monomer (F)] is mixed at a ratio of 30: 14: 6: 20: 30, and 1.5 mass times of dioxane is further mixed with this monomer mixture with respect to the total mass of all monomers. did. 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 73 ° 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 is filtered and recovered, dissolved again in dioxane, poured into a large amount of methanol / water mixed solvent to precipitate the resin, and the precipitated resin is filtered and recovered twice to perform reprecipitation. Purification gave a copolymer having a weight average molecular weight of about 8.1 × 10 ³ in a yield of 65%. This copolymer has the following structural units derived from the monomer (D), the monomer (E), the monomer (B), the monomer (C), and the monomer, respectively, and is referred to as a resin A1.

[Synthesis of Resin A2]
Monomer (A), monomer (E), monomer (B), monomer (C), and monomer (F) are in a molar ratio [monomer (A): monomer (E): monomer (B): monomer (C): The monomer (F)] was mixed at a ratio of 30: 14: 6: 20: 30, and 1.5 mass times dioxane was further mixed with respect to the total mass of all 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 73 ° 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 is filtered and collected, dissolved again in dioxane, poured into a large amount of methanol / water mixed solvent to precipitate the resin, and the precipitated resin is filtered and collected three times for reprecipitation. Purification gave a copolymer having a weight average molecular weight of about 7.8 × 10 ³ in a yield of 68%. This copolymer has the following structural units derived from the monomer (A), the monomer (E), the monomer (B), and the monomer (C), respectively, and is designated as resin A2.

[Synthesis of Resin A3]
Monomer (A), monomer (B) and monomer (C) are mixed so that the molar ratio [monomer (A): monomer (B): monomer (C)] is 50:25:25, , 1.5 mass times dioxane was mixed with respect to the total mass of all monomers. To the obtained mixture, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) were added as initiators in proportions of 1 mol% and 3 mol%, respectively, with respect to the total number of moles of all monomers. Then, this was heated at 80 ° C. for about 8 hours to carry out polymerization. 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 is filtered and collected, dissolved again in dioxane, poured into a large amount of methanol / water mixed solvent to precipitate the resin, and the precipitated resin is filtered and collected three times for reprecipitation. Purification gave a copolymer having a weight average molecular weight of about 9.2 × 10 ³ in a yield of 60%. This copolymer has structural units derived from the following monomers respectively derived from the monomer (A), the monomer (B), and the monomer (C), and this is referred to as a resin A3.

Examples 2 to 4 and Comparative Example 1
<Preparation of resist composition>
The resin A1, resin A2 or resin A3 obtained in Synthesis Example 1, the acid generator shown below, and the quencher shown below are mixed with the solvent shown below in parts by mass shown in Table 3. The obtained mixture was filtered through a fluororesin filter having a pore size of 0.2 μm to prepare a resist composition.

<Resin>
Resins A1 to A3
<Acid generator>
Acid Generator I1: Salt Represented by Formula (I1) Acid Generator I13: Salt Represented by Formula (I13) Acid Generator I69: Salt Represented by Formula (I69) Acid Generator B1: JP-A-2007 -Synthesis according to the example of No. 161707

<Basic compound: Quencher>
Quencher C1: 2,6-diisopropylaniline (manufactured by Tokyo Chemical Industry Co., Ltd.)
<Solvent>
Propylene glycol monomethyl ether acetate 265 parts 2-heptanone 20.0 parts Propylene glycol monomethyl ether 20.0 parts γ-butyrolactone 3.5 parts

<Manufacture of resist pattern and its evaluation>
An organic antireflective coating composition [ARC-29; manufactured by Nissan Chemical 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.
The obtained silicon wafer was pre-baked (PB) for 60 seconds on a direct hot plate at the temperature described in the “PB” column of Table 3. The wafer with the resist composition film thus formed was exposed to an exposure amount using an ArF excimer stepper for immersion exposure [XT: 1900 Gi; manufactured by ASML, NA = 1.35, 3/4 Annular XY polarized light]. The line-and-space pattern was subjected to immersion exposure by changing stepwise. Note that ultrapure water was used as the immersion medium.
After the exposure, post exposure bake (PEB) is performed on the hot plate at the temperature described in the “PEB” column of Table 3 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 film, the exposure amount at which the 50 nm line and space pattern becomes an exposure amount of 1: 1 was defined as the effective sensitivity.

In manufacturing the resist pattern as described above, the following items were evaluated.
<Focus margin evaluation (DOF)>
In the effective sensitivity, when the focus is shifted, the range (47.5 to 52.5 nm) in which the line width is 50 nm ± 5% is used as the line width index. DOF
Those exceeding 0.17 μm
Those exceeding 0.14 μm and 0.17 μm or less
○ over 0.09μm and 0.14μm or less
What was 0.09 micrometer or less was made into x.

<Shape evaluation>
A 50 nm line and space pattern was observed with a scanning electron microscope. As shown in FIG.
(A) A top shape and a skirt shape that are close to a rectangle are good.
(B) A case where the top shape is round or (c) a shape close to a T-shape or (d) a tail is seen was judged as x.
The focus margin evaluation (DOF) and shape results obtained as described above are expressed by the above-described level evaluation and are shown in Table 4.

  The resist composition containing the salt represented by the formula (I) has a focus margin (DOF) of “◯”, “◎”, or “◎◎”, and a good result is obtained. In addition, a resist pattern having a good shape could be produced. On the other hand, the resist composition of Comparative Example 1 containing no salt (I) had a poor focus margin (DOF) and a poor shape (x).

  The present resist composition containing the salt represented by the formula (I) and the salt represented by the formula (I) of the present invention can be used for fine processing of semiconductors.

Claims (7)

A salt represented by the formula (I).

[In the formula (I),
Q ¹ and Q ² each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group.
L ¹ represents a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, and the methylene group constituting the saturated hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
s represents an integer of 0 to 3.
R ¹ represents an alkyl group having 1 to 6 carbon atoms when s is 1, and represents an alkyl group having 1 to 6 carbon atoms independently of each other when s is 2 or 3, or the same carbon element Two R ¹ bonded to each other may form a carbonyl group together with the carbon atom, and the methylene group constituting the alkyl group may be replaced with an oxygen atom or a carbonyl group.
Z ⁺ represents an organic counter ion. ] L ¹ represents * —CO—O— (CH ₂ ) _u — (u represents an integer of 0 to 6. * represents a bond with —C (Q ¹ ) (Q ² ) —.) The salt according to claim 1, wherein The salt according to claim 1 or 2, wherein the Z ⁺ is an arylsulfonium cation.   The acid generator which contains the salt as described in any one of Claims 1-3 as an active ingredient.   5. An acid generator according to claim 4 and a resin, wherein the resin has an acid labile group and is insoluble or hardly soluble in an alkaline aqueous solution, and can be dissolved in an alkaline aqueous solution by acting with an acid. Resist composition which is resin.   Furthermore, the resist composition of Claim 5 containing a basic compound. (1) The process of apply | coating the resist composition of Claim 5 or 6 on a board | substrate,
(2) The process of drying the composition after application | coating and forming a composition layer,
(3) a step of exposing the composition layer using an exposure machine;
(4) a step of heating the composition layer after exposure, and (5) a step of developing the composition layer after heating,
A method for producing a resist pattern including:

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