JP5750317B2 - Salt, acid generator and resist composition - Google Patents

Description

  The present invention relates to a salt, an acid generator, and a resist composition.

  Patent Document 1 describes a photoresist composition containing triphenylsulfonium 1-((3-hydroxyadamantyl) methoxycarbonyl) difluoromethanesulfonate as a salt for an acid generator.

JP 2006-257078 A

  A resist composition containing a conventional salt as an acid generator may not always satisfy the exposure margin (EL) and the focus margin (DOF) when forming a resist pattern.

［式（Ｉ）中、
Ｒ^１及びＲ^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２価の飽和炭化水素基に含まれる−ＣＨ_２−は、−Ｏ−又は−ＣＯ−で置き換わっていてもよい。
環Ｗ^１は、炭素数２〜３６の複素環を表す。
Ｒ^３は、水素原子又は炭素数１〜１２の炭化水素基を表し、該炭化水素基に含まれる−ＣＨ_２−は、−Ｏ−又は−ＣＯ−で置き換わっていてもよい。
Ｒ^４は、それぞれ独立に、炭素数１〜６の炭化水素基を表し、該炭化水素基に含まれる−ＣＨ_２−は、−Ｏ−又は−ＣＯ−で置き換わっていてもよい。
ｍは、０〜６の整数を表す。
Ｚ^＋は、有機カチオンを表す。］ The present invention includes the following inventions.
[1] A salt represented by the formula (I).

[In the formula (I),
R ¹ and R ² each independently 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 —CH ₂ — contained in the divalent saturated hydrocarbon group may be replaced by —O— or —CO—. .
Ring ^{W 1} represents a heterocycle of the C 2 to C 36.
R ³ represents a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, and —CH ₂ — contained in the hydrocarbon group may be replaced by —O— or —CO—.
R ⁴ each independently represents a hydrocarbon group having 1 to 6 carbon atoms, and —CH ₂ — contained in the hydrocarbon group may be replaced by —O— or —CO—.
m represents an integer of 0-6.
Z ⁺ represents an organic cation. ]

［式（Ｌ１−１）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。
＊は−Ｃ（Ｒ^１）（Ｒ^２）−との結合手を表す。］
〔３〕Ｚ^＋が、トリアリールスルホニウムカチオンである〔１〕又は〔２〕の塩。 [2] The salt of [1], wherein L ¹ is a group represented by the formula (L1-1).

[In Formula (L1-1), L ^b2 represents a single bond or a divalent saturated hydrocarbon group having 1 to 15 carbon atoms.
* Represents a bond with —C (R ¹ ) (R ² ) —. ]
[3] The salt of [1] or [2], wherein Z ⁺ is a triarylsulfonium cation.

  [4] An acid generator containing the salt according to any one of [1] to [3].

[5] The acid generator of [4] and a resin, wherein the resin has an acid labile group and is insoluble or hardly soluble in an alkaline aqueous 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 of [4] or [5] on a substrate,
(2) The process of drying the composition after application | coating and forming a composition layer,
(3) a step of exposing the composition layer using an exposure machine;
(4) A step of heating the composition layer after exposure,
(5) A method for producing a resist pattern, comprising a step of developing the heated composition layer using a developing device.

  According to the salt of the present invention, a resist composition having a wide exposure margin (EL) and focus margin (DOF) when forming a resist pattern can be obtained.

In this specification, unless otherwise specified, specific chemical substituents described later can be applied to any chemical structural formula having the same substituents while appropriately selecting the number of carbon atoms. Those which can take any of linear, branched or cyclic are included unless otherwise specified, and in the same group, linear, branched and / or cyclic partial structures are mixed. It may be. When stereoisomers exist, all of those stereoisomers are included.
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、
Ｒ^１及びＲ^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２価の飽和炭化水素基に含まれる−ＣＨ_２−は、−Ｏ−又は−ＣＯ−で置き換わっていてもよい。
環Ｗ^１は、炭素数２〜３６の複素環を表す。
Ｒ^３は、水素原子又は炭素数１〜１２の炭化水素基を表し、該炭化水素基に含まれる−ＣＨ_２−は、−Ｏ−又は−ＣＯ−で置き換わっていてもよい。
Ｒ^４は、それぞれ独立に、炭素数１〜６の炭化水素基を表し、該炭化水素基に含まれる−ＣＨ_２−は、−Ｏ−又は−ＣＯ−で置き換わっていてもよい。
ｍは、０〜６の整数を表す。
Ｚ^＋は、有機カチオンを表す。］ <Salt represented by formula (I)>
The salt of the present invention is represented by the formula (I).

[In the formula (I),
R ¹ and R 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 —CH ₂ — contained in the divalent saturated hydrocarbon group may be replaced by —O— or —CO—. .
Ring ^{W 1} represents a heterocycle of the C 2 to C 36.
R ³ represents a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, and —CH ₂ — contained in the hydrocarbon group may be replaced by —O— or —CO—.
R ⁴ each independently represents a hydrocarbon group having 1 to 6 carbon atoms, and —CH ₂ — contained in the hydrocarbon group may be replaced by —O— or —CO—.
m represents an integer of 0-6.
Z ⁺ represents an organic cation. ]

  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.

Examples of the divalent saturated hydrocarbon group include a linear alkanediyl group, a branched alkanediyl group, a monocyclic or polycyclic divalent saturated cyclic hydrocarbon group, and two of these groups. A combination of the above may also be used.
Specifically, 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, Linear alkanediyl groups such as 17-diyl group, ethane-1,1-diyl group, propane-1,1-diyl group, propane-2,2-diyl group;
An alkyl group (particularly an alkyl group having 1 to 4 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group); For example, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl A branched alkanediyl group such as a 2-methylbutane-1,4-diyl group;
Cyclobutane-1,3-diyl group, cyclopentane-1,3-diyl group, cyclohexane-1,2-diyl group, 1-methylcyclohexane-1,2-diyl group, cyclohexane-1,4-diyl group, cyclo A monocyclic saturated cyclic hydrocarbon group which is a cycloalkanediyl group such as an octane-1,2-diyl group or a cyclooctane-1,5-diyl group;
A polycyclic group such as norbornane-2,3-diyl group, norbornane-1,4-diyl group, norbornane-2,5-diyl group, adamantane-1,5-diyl group, adamantane-2,6-diyl group, etc. Saturated cyclic hydrocarbon group etc. are mentioned.
The divalent saturated cyclic hydrocarbon group may be a group obtained by removing any one hydrogen atom from a monovalent saturated cyclic hydrocarbon group described later.

Any heterocyclic ring may be used as long as it contains one or more nitrogen atoms, and may further contain one or more nitrogen atoms, one or more oxygen atoms, one or more sulfur atoms, and the like. The heterocyclic ring may be an aromatic heterocyclic ring, or may have no aromaticity, and may be a monocyclic, polycyclic, condensed ring or bridged ring. .
Examples of the heterocyclic ring include the following rings. However, —CH ₂ — contained in these heterocyclic rings may be replaced by —O— or —CO—. Among these, a ring represented by the formula (W1), a ring represented by the formula (W2), and a ring represented by the formula (W3) are preferable. * Represents a bond to ^{L 1.}

Examples of the hydrocarbon group include an aliphatic hydrocarbon group, a saturated cyclic hydrocarbon group, and an aromatic hydrocarbon group.
Examples of the aliphatic hydrocarbon group include methyl group, ethyl group, n-propyl group, 1-methylethyl group (isopropyl group), n-butyl group, 1,1-dimethylethyl group (tert-butyl group), 2, 2-dimethylethyl group, 1-methylpropyl group, 2-methylpropyl group, 1,2-dimethylpropyl group, 2,2-dimethylpropyl group, 1-ethylpropyl group, n-pentyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, n-hexyl group, 1-propylbutyl group, 1-methylpentyl group, 1,4-dimethylhexyl group, heptyl group, 1-methylheptyl group, octyl group, methyloctyl group And alkyl groups such as methylnonyl group, 2-ethylhexyl group, nonyl group, decyl group, undecyl group and dodecyl group.

芳香族炭化水素基としては、フェニル基、ナフチル基、ｐ−メチルフェニル基、ｐ−エチルフェニル基、ｐ−ｔｅｒｔ−ブチルフェニル基、ｐ−シクロへキシルフェニル基、ｐ−メトキシフェニル基、ｐ−アダマンチルフェニル基、トリル基、キシリル基、クメニル基、メシチル基、ビフェニル基、アントリル基、フェナントリル基、２，６−ジエチルフェニル基、２−メチル−６−エチルフェニル等のアリール基等が挙げられる。 The saturated cyclic hydrocarbon may be monocyclic or polycyclic. Examples thereof include monocyclic saturated cyclic hydrocarbon groups such as a cycloalkyl group (for example, a cyclopentyl group, a cyclohexyl group, a methylcyclohexyl group, a dimethylcyclohexyl group, a cycloheptyl group, and a cyclooctyl group). Polycyclic saturation such as groups obtained by hydrogenating condensed aromatic hydrocarbon groups (for example, hydronaphthyl group) and bridged cyclic hydrocarbon groups (for example, adamantyl group, norbornyl group, methylnorbornyl group) A cyclic hydrocarbon group is mentioned. Further, a group in which a bridging ring (for example, norbornane ring) and a single ring (for example, cycloheptane ring, cyclohexane ring) or polycyclic (for example, decahydronaphthalene ring) are condensed, and the bridging rings are condensed as shown below. Groups; groups in which these are combined (methylcyclohexyl group, dimethylcyclohexyl group, methylnorbornyl group) and the like.

Examples of the aromatic hydrocarbon group include phenyl group, naphthyl group, p-methylphenyl group, p-ethylphenyl group, p-tert-butylphenyl group, p-cyclohexylphenyl group, p-methoxyphenyl group, p- Examples include an adamantylphenyl group, a tolyl group, a xylyl group, a cumenyl group, a mesityl group, a biphenyl group, an anthryl group, a phenanthryl group, a 2,6-diethylphenyl group, and an aryl group such as 2-methyl-6-ethylphenyl.

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

Examples of the group in which —CH ₂ — in the divalent saturated hydrocarbon group of L ¹ is replaced by —O— or —CO— include formulas (L1-1) to (L1-6). . L ¹ is preferably any of formula (L1-1) to formula (L1-4), more preferably formula (L1-1) or formula (L1-2). Incidentally, the formula (L1-1) ~ formula (L1-6) is described together the left and right in formula (I), and the left ^{C (R 1) (R 2} ) - bound to, the right side Bonded with ring W ¹ . The same applies to specific examples of the following formulas (L1-1) to (L1-6).

式（Ｌ１−１）〜式（Ｌ１−６）中、
Ｌ^b2は、単結合又は炭素数１〜１５の２価の飽和炭化水素基を表す。
Ｌ^b3は、単結合又は炭素数１〜１２の２価の飽和炭化水素基を表す。
Ｌ^b4は、炭素数１〜１３の２価の飽和炭化水素基を表す。
Ｌ^b5は、炭素数１〜１５の２価の飽和炭化水素基を表す。
Ｌ^b6及びＬ^b7は、それぞれ独立に、炭素数１〜１５の２価の飽和炭化水素基を表す。
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１〜１１の２価の飽和炭化水素基を表す。
中でも、式（Ｌ１−１）で表される２価の基、式（Ｌ１−２）で表される２価の基及び式（Ｌ１−６）で表される２価の基が好ましい。式（Ｌ１−１）で表される２価の基としては、Ｌ^b2が単結合又は−ＣＨ_２−である式（Ｌ１−１）で表される２価の基が好ましい。式（Ｌ１−６）で表される２価の基としては、Ｌ^b９が単結合又は−ＣＨ_２−である式（Ｌ１−６）で表される２価の基が好ましく、さらにＬ^b10が

である式（Ｌ１−６）で表される２価の基がより好ましい。

In formula (L1-1) to formula (L1-6),
L ^b2 represents a single bond or a divalent saturated hydrocarbon group having 1 to 15 carbon atoms.
L ^b3 represents a single bond or a divalent saturated hydrocarbon group having 1 to 12 carbon atoms.
L ^b4 represents a divalent saturated hydrocarbon group having 1 to 13 carbon atoms.
L ^b5 represents a divalent saturated hydrocarbon group having 1 to 15 carbon atoms.
L ^b6 and L ^b7 each independently represent a divalent saturated hydrocarbon group having 1 to 15 carbon atoms.
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 11 carbon atoms.
Among these, a divalent group represented by the formula (L1-1), a divalent group represented by the formula (L1-2), and a divalent group represented by the formula (L1-6) are preferable. As the divalent group represented by the formula (L1-1), a divalent group represented by the formula (L1-1) in which L ^b2 is a single bond or —CH ₂ — is preferable. Examples of the divalent group represented by the formula (L1-6), L ^b9 represents a single bond or -CH ₂ - divalent group is preferably represented by a is Formula (L1-6), further L ^b10

The divalent group represented by the formula (L1-6) is more preferable.

Examples of the divalent group represented by the formula (L1-1) include the following.

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

Examples of the divalent group represented by the formula (L1-3) include the following.

Examples of the divalent group represented by the formula (L1-4) include the following.

Examples of the divalent group represented by the formula (L1-5) include the following.

Examples of the divalent group represented by the formula (L1-6) include the following.

R ³ is preferably a hydrogen atom, a methyl group, an ethyl group or a tert-butoxycarbonyl group, and more preferably a hydrogen atom, a methyl group or a tert-butoxycarbonyl group.
R ⁴ is preferably a hydrogen atom, a methyl group, an ethyl group, a methylcarbonyloxy group (acetyloxy group), an ethylcarbonyloxy group or the like.

Examples of the salt represented by the formula (I) include the following salts.

Examples of Z ⁺ include onium cations such as sulfonium cations, iodonium cations, ammonium cations, benzothiazolium cations, and phosphonium cations. Among these, a sulfonium cation and an iodonium cation are preferable, and an arylsulfonium cation is more preferable.

Examples of Z ⁺ include formula (Z1) to formula (Z4).

In formula (Z1) to formula (Z4),
P ^{a to} P ^c each independently represent an aliphatic hydrocarbon group having 1 to 30 carbon atoms, a saturated cyclic hydrocarbon group having 3 to 36 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms. The hydrogen atom contained in the aliphatic hydrocarbon group may be substituted with a hydroxy group, an alkoxy group having 1 to 12 carbon atoms or an aromatic hydrocarbon group having 6 to 18 carbon atoms, and the saturated cyclic hydrocarbon group May be substituted with a halogen atom, an acyl group having 2 to 4 carbon atoms, or a glycidyloxy group, and the hydrogen atom contained in the aromatic hydrocarbon group may be a halogen atom, a hydroxy group, or a carbon atom. It may be substituted with an aliphatic hydrocarbon group having 1 to 36 carbon atoms, a saturated cyclic hydrocarbon group having 3 to 36 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. P ^a and P ^b may together form a ring containing a heteroatom.

P ⁴ and P ⁵ each independently represent a hydroxy group, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.
P ⁶ and P ⁷ each independently represent an aliphatic hydrocarbon group having 1 to 36 carbon atoms or a saturated cyclic hydrocarbon group having 3 to 36 carbon atoms.
P ⁸ represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 36 carbon atoms, a saturated cyclic hydrocarbon group having 3 to 36 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms.
The aliphatic hydrocarbon group of P ^{6 to} P ⁸ preferably has 1 to 12 carbon atoms, and the saturated cyclic hydrocarbon group preferably has 3 to 36 carbon atoms, more preferably 4 to 12 carbon atoms.
P ⁹ represents an aliphatic hydrocarbon group having 1 to 12 carbon atoms, a saturated cyclic hydrocarbon group having 3 to 18 carbon atoms, and an aromatic hydrocarbon group having 6 to 18 carbon atoms. The hydrogen atom contained in the aromatic hydrocarbon group is an aliphatic hydrocarbon group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, a saturated cyclic hydrocarbon group having 3 to 18 carbon atoms, or an alkylcarbonyloxy group. May be substituted.
P ⁶ and P ⁷ may be bonded together with a sulfur atom to which they are bonded to form a 3- to 12-membered ring (preferably a 3- to 7-membered ring), and P ⁸ and P ⁹ are , together with the -CH-CO- which they are attached 3 twelve-membered ring (preferably a 3-membered ring to 7-membered ring) may form a, -CH ₂ contained in these rings - is - O-, -S-, and -CO- may be substituted.
P < ¹⁰ > -P < ¹⁵ > represents a hydroxyl group, a C1-C12 aliphatic hydrocarbon group, or a C1-C12 alkoxy group each independently.
E represents -S- or -O-.
i, j, p, r, x and y each independently represents an integer of 0 to 5;
q represents 0 or 1;
v and w each independently represent an integer of 0 to 4.
When i is 2 or more, the plurality of P ⁴ may be the same as or different from each other. Similarly, when any of j, p, r, x, y, v, and w is 2, Any of the plurality of P ⁵ and P ^{10 to} P ¹⁵ may be the same as or different from each other.

Examples of the aliphatic hydrocarbon group and saturated cyclic hydrocarbon group are the same as those described above.
As the alkoxy group, methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, sec-butoxy group, tert-butoxy group, n-pentoxy group, n-hexoxy group, heptoxy group, octoxy group , 2-ethylhexoxy group, nonyloxy group, decyloxy group, undecyloxy group, dodecyloxy group and the like.
Examples of the halogen atom include fluorine, chlorine, bromine and iodine atoms.
Examples of the acyl group include an acetyl group, a propionyl group, and a butyryl group.
Examples of the alkylcarbonyloxy group include a methylcarbonyloxy group, an ethylcarbonyloxy group, an n-propylcarbonyloxy group, an isopropylcarbonyloxy group, an n-butylcarbonyloxy group, a sec-butylcarbonyloxy group, a tert-butylcarbonyloxy group, Examples thereof include a pentylcarbonyloxy group, a hexylcarbonyloxy group, an octylcarbonyloxy group, and a 2-ethylhexylcarbonyloxy group.

The ring which may have a heteroatom formed by combining P ^a and P ^b 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.
Examples of the 3-membered to 12-membered ring formed by combining P ⁶ and P ⁷ and P ⁸ and P ⁹ with each other include saturated cyclic hydrocarbon groups, aromatic hydrocarbon groups, and combinations thereof.
Examples of the ring formed by P ⁶ and P ⁷ together with the sulfur atom include a thiolane-1-ium ring (tetrahydrothiophenium ring), a thian-1-ium ring, and a 1,4-oxathian-4-ium ring. Can be mentioned.
Examples of the ring formed by P ⁸ and P ⁹ together with —CH—CO— include an oxocycloheptane ring, an oxocyclohexane ring, an oxonorbornane ring, and an oxoadamantane ring.

Preferred aliphatic hydrocarbon groups in formula (Z1) to formula (Z4) are methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, pentyl group, A hexyl group, an octyl group, and a 2-ethylhexyl group.
Preferred saturated cyclic hydrocarbon groups are cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclodecyl group, 2-alkyl-2-adamantyl group, 1- (1-adamantyl) -1-alkyl group, And an 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, naphthyl group. It is.
Examples of the aliphatic hydrocarbon group (aralkyl group) whose substituent is an aromatic hydrocarbon group include a benzyl group, a phenethyl group, a phenylpropyl group, a trityl group, a naphthylmethyl group, and a naphthylethyl group.

  Among the cations represented by the formulas (Z1) to (Z4), the formula (Z1) is preferable, the cation represented by the formula (Z5) is more preferable, and the triphenylsulfonium cation (in the formula (Z5), More preferably, z is 0).

式（Ｚ５）において、Ｐ^１〜Ｐ^３は、それぞれ独立に、ハロゲン原子、ヒドロキシ基、炭素数１〜３６の脂肪族炭化水素基、炭素数３〜３６の飽和環状炭化水素基又は炭素数１〜１２のアルコキシ基を表し、Ｐ^１〜Ｐ^３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てもよく、ヘテロ原子を含む環を形成してもよい。
ｚ１、ｚ２及びｚ３は、それぞれ独立に、０〜５の整数を表す。ｚ１が２以上のとき、複数のＰ^１は互いに同一でも異なってもよく、ｚ２が２以上のとき、複数のＰ^２は互いに同一でも異なってもよく、ｚ３以上のとき、数のＰ^３は互いに同一でも異なってもよい。

In formula (Z5), P ^{1 to} P ³ each independently represent a halogen atom, a hydroxy group, an aliphatic hydrocarbon group having 1 to 36 carbon atoms, a saturated cyclic hydrocarbon group having 3 to 36 carbon atoms, or 1 carbon atom. Represents an alkoxy group of ˜12, and two selected from P ^{1 to} P ³ together may represent a single bond, —O— or a divalent aliphatic hydrocarbon group of 1 to 4 carbon atoms, You may form the ring containing an atom.
z1, z2 and z3 each independently represents an integer of 0 to 5. When z1 is 2 or more, a plurality of P ¹ may be the same or different from each other, when z2 is 2 or more, P ² may be the same or different from each other, when more than z3, the number of P ³ is They may be the same or different.

The aliphatic hydrocarbon group here preferably has 1 to 12 carbon atoms, and the saturated cyclic hydrocarbon group preferably has 4 to 36 carbon atoms.
The aliphatic hydrocarbon group may be substituted with a hydroxy group, an alkoxy group having 1 to 12 carbon atoms or an aromatic hydrocarbon group having 6 to 18 carbon atoms, and the saturated cyclic hydrocarbon group includes a halogen atom, It may be substituted with an acyl group having 2 to 4 carbon atoms or a glycidyloxy group.
The ring containing a heteroatom may be any of monocyclic, polycyclic, aromatic, non-aromatic, saturated and unsaturated rings, as long as it contains one or more sulfur atoms. Further, it may contain one or more sulfur atoms and / or one or more oxygen atoms.
Among them, each of P ^{1 to} P ³ independently represents 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, or P ¹ two selected from to P ³ but represents -O- together, it is preferable to form a ring containing a sulfur atom.
z1 to z3 are preferably each independently 0 or 1.

Examples of the cation represented by the formula (Z1) or the formula (Z5) include the following.

The following are mentioned as a specific example of the cation in which the ring containing a sulfur atom was formed among the cations represented by a formula (Z5).

Specific examples of the cation (Z1) include the following.

Specific examples of the cation (Z2) include the following.

Specific examples of the cation (Z3) include the following.

Specific examples of the cation (Z4) include the following.

  The salt represented by the formula (I) is a combination of the above-mentioned anions and organic cations. Although the above-mentioned anion and cation can be combined arbitrarily, the salt represented below is preferable. In the following formulae, the definition of the substituent has the same meaning as described above.

Furthermore, the following salts are more preferable.

［式中、Ｒ^１〜Ｒ^３、Ｚ、Ｗ^１及びＷ^２は、上記と同じ意味を表す。］
用いる溶媒は、クロロホルム等が挙げられる。
式（Ｉａ−２）で表される化合物としては、４−ヒドロキシ−１−メチルピペリジン、４−ヒドロキシ−２，２，６，６−テトラメチルピペリジン、トロピン等が挙げられる。
式（Ｉａ−１）で表される塩は、式（Ｉａ−３）で表される塩と式（Ｉａ−４）で表される化合物とを反応させることにより、得ることができる。
式（Ｉａ−３）で表される塩は、例えば、特開２００８−１３５５１号公報に記載された方法で合成することができる。

The salt represented by the formula (I) can be produced by a method known in the art.
For example, by reacting a salt represented by the formula (Ia-1) and a compound represented by the formula (Ia-2) in a solvent, L ^{1 of the} salt represented by the formula (I) is —CO 2. A salt represented by the formula (Ia) which is —O— can be obtained.

[Wherein R ^{1 to} R ³ , Z, W ¹ and W ² represent the same meaning as described above. ]
Examples of the solvent used include chloroform.
Examples of the compound represented by the formula (Ia-2) include 4-hydroxy-1-methylpiperidine, 4-hydroxy-2,2,6,6-tetramethylpiperidine, tropine and the like.
The salt represented by the formula (Ia-1) can be obtained by reacting the salt represented by the formula (Ia-3) with the compound represented by the formula (Ia-4).
The salt represented by the formula (Ia-3) can be synthesized, for example, by the method described in JP-A-2008-13551.

<Acid generator>
The acid generator of the present invention contains a salt represented by the formula (I). When used as an acid generator, the salt represented by the formula (I) may be used alone or in combination of two or more.
The acid generator of the present invention further includes a known salt other than the salt represented by the formula (I), a salt composed of a cation and a known anion contained in the salt represented by the formula (I), and a formula ( A salt composed of an anion contained in the salt represented by I) and a known cation may be included.
When the acid generator of the present invention contains a salt represented by the formula (I) and a known salt other than the salt represented by the formula (I), the salt represented by the formula (I) and the formula ( Known salts other than the salt represented by I) are, for example, 5:95 to 95: 5, preferably 10:90 to 90:10, and more preferably 15:85 to 85:15 mass ratio.

<Resist composition>
The resist composition of the present invention contains the acid generator described above and a resin.
<Acid generator>
The content of the acid generator contained in the resist composition of the present invention is preferably 1% by mass or more (more preferably 3% by mass or more), preferably 30% by mass or less, based on the resin (A) described later. (More preferably 25% by mass or less).
Further, when the resist composition of the present invention contains an acid generator containing a salt represented by the formula (I) and a known salt other than the salt represented by the formula (I), the total content thereof Is preferably 1% by mass or more (more preferably 3% by mass or more), preferably 40% by mass or less (more preferably 35% by mass or less) with respect to the resin described later.

<Resin (hereinafter sometimes referred to as “resin (A)”)>
Resin (A) is a resin that becomes alkali-soluble by the action of an acid. “Becomes alkali-soluble by the action of an acid” means insoluble or hardly soluble in an aqueous alkali solution before contact with an acid, but becomes soluble in an aqueous alkali solution after contact with an acid. A resin that becomes alkali-soluble by the action of an acid is produced by polymerizing a monomer having an acid-labile group (hereinafter sometimes referred to as “monomer having an acid-labile group (a1)”). Can do. As the monomer (a1) having an acid labile group, one type may be used alone, or two or more types may be used in combination.

<Monomer (a1) having an acid labile group>
The “acid-labile group” means a group that forms a hydrophilic group (for example, a carboxy group or a hydroxy group) by leaving the leaving group upon contact with an acid.
Examples of the acid labile group include an alkoxycarbonyl group represented by the formula (1) in which —O— is bonded to a tertiary carbon atom. Hereinafter, the group represented by the formula (1) may be referred to as “acid-labile group (1)”.

式（１）において、Ｒ^a1〜Ｒ^a3は、それぞれ独立に、炭素数１〜８の脂肪族炭化水素基又は炭素数３〜２０の飽和環状炭化水素基を表すか、或いはＲ^a1及びＲ^a2は互いに結合して炭素数３〜２０の環を形成する。＊は結合手を表す（以下同じ）。

In the formula (1), R ^{a1 to} R ^a3 each independently represent an aliphatic hydrocarbon group having 1 to 8 carbon atoms or a saturated cyclic hydrocarbon group having 3 to 20 carbon atoms, or R ^a1 and R ^a2 Combine with each other to form a ring having 3 to 20 carbon atoms. * Represents a bond (same below).

Examples of the aliphatic hydrocarbon group and the saturated cyclic hydrocarbon group include the same as those described above.
In the formula (1), the saturated cyclic hydrocarbon group preferably has 1 to 16 carbon atoms.

このような環の炭素数は、好ましくは炭素数３〜１２である。 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 the following groups.

Such a ring preferably has 3 to 12 carbon atoms.

Examples of acid labile groups include:
1,1-dialkylalkoxycarbonyl group (in the formula (1), R ^{a1 to} R ^a3 are alkyl groups, preferably tert-butoxycarbonyl group),
2-alkyladamantan-2-yloxycarbonyl group (in the formula (1), R ^a1 , R ^a2 and a carbon atom form an adamantyl group and R ^a3 is an alkyl group) and 1- (adamantane-1- Yl) -1-alkylalkoxycarbonyl group (in the formula (1), R ^a1 and R ^a2 are alkyl groups, and R ^a3 is an adamantyl group).

式（２）において、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、あるいは、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に含まれる−ＣＨ_２−は、−Ｏ−、−Ｓ−又は−ＣＯ−で置き換わっていてもよい。＊は結合手を表す。 Further, examples of the acid labile group in the case where the hydrophilic group is a hydroxy group include those in which a hydrogen atom of the hydroxy group is replaced with an organic residue to become a group containing an acetal structure. Among such acid labile groups, preferred acid labile groups include, for example, those represented by the following formula (2). Hereinafter, it may be referred to as “acid-labile group (2)”.

In Formula (2), R ^b1 and R ^b2 each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, and R ^b3 represents a hydrocarbon group having 1 to 20 carbon atoms, or , R ^b2 and R ^b3 are bonded to each other to form a ring having 3 to 20 carbon atoms together with the carbon atom and the oxygen atom to which they are bonded. R ^b2 and R ^b3 may be a ring formed by bonding to each other or —CH ₂ — contained in the hydrocarbon group may be replaced by —O—, —S— or —CO—. * Represents a bond.

Examples of the hydrocarbon group of R ^{b1 to} R ^b3 include an aliphatic hydrocarbon group, a saturated cyclic hydrocarbon group, and an aromatic hydrocarbon group. Here, examples of the aliphatic hydrocarbon group, the saturated cyclic hydrocarbon group, and the aromatic hydrocarbon group include those described above.
^Examples of the ring formed by combining R ^b2 and R ^b3 with each other include the same ring formed by combining R ^a1 and R ^a2 with each other.
At least one of R ^{b1 to} R ^b2 is preferably a hydrogen atom.

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

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

Among the (meth) acrylic monomers having an acid labile group, those having a saturated cyclic hydrocarbon group having 5 to 20 carbon atoms are preferred. If a resin obtained by polymerizing a monomer having a bulky structure such as a saturated cyclic hydrocarbon group is used, the resolution of the resist can be improved.
Examples of the saturated cyclic hydrocarbon group are the same as those described above.

  Among (meth) acrylic monomers having an acid labile group and a saturated cyclic hydrocarbon group, a monomer having an adamantyl group represented by formula (a-1) or a formula (a-2) Monomers having a cyclohexyl group are preferred. These may be used alone or in combination of two or more.

式（ａ−１）及び式（ａ−２）において、Ｍは、それぞれ独立に、−Ｏ−又は−Ｏ−（ＣＨ₂）_k−ＣＯ−Ｏ−を表し、ｋは１〜７の整数を表す。ただし、Ｍで列挙した−Ｏ−等は、それぞれ、左側で式（ａ−１）及び式（ａ−２）の−ＣＯ−と結合し、右側でアダマンチル基又はシクロへキシル基と結合することを意味する。
Ｒ⁴は、それぞれ独立に、水素原子又はメチル基を表す。
Ｒ⁵は、それぞれ独立に、炭素数１〜８の脂肪族炭化水素基又は炭素数３〜１０の飽和環状炭化水素基を表し、
ｓは０〜１４の整数を表し、ｔは０〜１０の整数を表す。
ｎ２は０〜３の整数を表す。

In Formula (a-1) and Formula (a-2), M independently represents —O— or —O— (CH ₂ ) _k —CO—O—, and k represents an integer of 1 to 7. Represent. However, —O— and the like enumerated in M are bonded to the —CO— of the formula (a-1) and the formula (a-2) on the left side and to the adamantyl group or the cyclohexyl group on the right side. Means.
R ⁴ each independently represents a hydrogen atom or a methyl group.
R ⁵ each independently represents an aliphatic hydrocarbon group having 1 to 8 carbon atoms or a saturated cyclic hydrocarbon group having 3 to 10 carbon atoms,
s represents an integer of 0 to 14, and t represents an integer of 0 to 10.
n2 represents an integer of 0 to 3.

M is preferably —O— or —O— (CH ₂ ) _f —CO—O— (wherein f is an integer of 1 to 4), more preferably —O—.
R ⁴ is preferably a methyl group.
The aliphatic hydrocarbon group for R ⁵ preferably has 6 or less carbon atoms. The saturated cyclic hydrocarbon group preferably has 8 or less carbon atoms, more preferably 6 or less carbon atoms.
s is preferably an integer of 0 to 3, more preferably 0 or 1. t is preferably an integer of 0 to 3, more preferably 0 or 1. n2 is preferably 0 or 1.

  As a monomer (a-1) which has an adamantyl group, the following are mentioned, for example. Among these, 2-methyladamantan-2-yl (meth) acrylate, 2-ethyladamantan-2-yl (meth) acrylate, and 2-isopropyladamantan-2-yl (meth) acrylate are preferable, and those in methacrylate form Is more preferable.

  Examples of the monomer (a-2) having a cyclohexyl group include the following. Among these, 1-ethylcyclohexane-1-yl (meth) acrylate is preferable, and 1-ethylcyclohexane-1-yl methacrylate is more preferable.

  When resin (A) contains the structural unit derived from the monomer represented by Formula (a-1) and / or Formula (a-2), these total content is in all the structural units of resin (A). On the other hand, it is 10-95 mol% normally, Preferably it is 15-90 mol%, More preferably, it is 20-85 mol%.

  Examples of the monomer having an acid labile group and a carbon-carbon double bond include a monomer having a norbornene ring represented by the formula (a-3). Since the resin having a structural unit derived from the monomer (a-3) having a norbornene ring has a bulky structure, the resolution of the resist can be improved. In addition, since a rigid norbornane ring is introduced into the main chain of the resin, the resistance to dry etching of the resist can be improved.

式（ａ−３）において、
Ｒ^６は、水素原子、置換基（例えば、ヒドロキシ基）を有していてもよい炭素数１〜３の脂肪族炭化水素基、カルボキシ基、シアノ基又は基−ＣＯＯＲ^ｍを表す。Ｒ^ｍは、炭素数１〜８の脂肪族炭化水素基又は炭素数１〜２０の飽和環状炭化水素基を表し、該脂肪族炭化水素基及び該飽和環状炭化水素基の水素原子はヒドロキシ基で置換されていてもよく、該脂肪族炭化水素基及び該飽和環状炭化水素基に含まれる−ＣＨ_２−は−Ｏ−又は−ＣＯ−で置き換わっていてもよい。
Ｒ^７〜Ｒ^９は、それぞれ独立に、炭素数１〜１２の脂肪族炭化水素基又は炭素数３〜２０の飽和環状炭化水素基を表すか、Ｒ^８及びＲ^９は互いに結合して環を形成していてもよい。該脂肪族炭化水素基及び該飽和環状炭化水素基の水素原子はヒドロキシ基等で置換されていてもよく、該脂肪族炭化水素基及び該飽和環状炭化水素基に含まれる−ＣＨ_２−は−Ｏ−又は−ＣＯ−で置き換わっていてもよい。
Ｒ^６の置換基を有していてもよい脂肪族炭化水素基としては、例えば、メチル基、エチル基、プロピル基、ヒドロキシメチル基、２−ヒドロキシエチル基などが挙げられる。
Ｒ^ｍとしては、例えば、メチル基、エチル基、プロピル基、２−オキソオキソラン−３−イル基又は２−オキソオキソラン−４−イル基などが挙げられる。

In formula (a-3),
R ⁶ represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 3 carbon atoms which may have a substituent (for example, a hydroxy group), a carboxy group, a cyano group, or a group —COOR ^m . R ^m represents an aliphatic hydrocarbon group having 1 to 8 carbon atoms or a saturated cyclic hydrocarbon group having 1 to 20 carbon atoms, and the hydrogen atom of the aliphatic hydrocarbon group and the saturated cyclic hydrocarbon group is a hydroxy group. It may be substituted, and —CH ₂ — contained in the aliphatic hydrocarbon group and the saturated cyclic hydrocarbon group may be replaced with —O— or —CO—.
R ^{7 to} R ⁹ each independently represents an aliphatic hydrocarbon group having 1 to 12 carbon atoms or a saturated cyclic hydrocarbon group having 3 to 20 carbon atoms, or R ⁸ and R ⁹ are bonded to each other to form a ring. It may be formed. The hydrogen atom of the aliphatic hydrocarbon group and the saturated cyclic hydrocarbon group may be substituted with a hydroxy group or the like, and —CH ₂ — contained in the aliphatic hydrocarbon group and the saturated cyclic hydrocarbon group is — O- or -CO- may be substituted.
Examples of the aliphatic hydrocarbon group which may have a substituent for R ⁶ include a methyl group, an ethyl group, a propyl group, a hydroxymethyl group, and a 2-hydroxyethyl group.
Examples of R ^m include a methyl group, an ethyl group, a propyl group, a 2-oxooxolan-3-yl group, and a 2-oxooxolan-4-yl group.

Examples of R ^{7 to} R ⁹ include a methyl group, an ethyl group, a cyclohexyl group, a methylcyclohexyl group, a hydroxycyclohexyl group, an oxocyclohexyl group, and an adamantyl group.
Examples of the saturated cyclic hydrocarbon group formed by R ⁸ , R ⁹ and the carbon to which they are bonded include a cyclohexyl group and an adamantyl group.

  Examples of the monomer (a-3) having a norbornene ring include 5-norbornene-2-carboxylic acid-tert-butyl, 5-norbornene-2-carboxylic acid 1-cyclohexyl-1-methylethyl, and 5-norbornene-2. -1-methylcyclohexyl carboxylate, 2-methyl-2-adamantyl 5-norbornene-2-carboxylate, 2-ethyl-2-adamantyl 5-norbornene-2-carboxylate, 5-norbornene-2-carboxylic acid 1- (4-methylcyclohexyl) -1-methylethyl, 5-norbornene-2-carboxylic acid 1- (4-hydroxycyclohexyl) -1-methylethyl, 5-norbornene-2-carboxylic acid 1-methyl-1- (4 -Oxocyclohexyl) ethyl, 5-norbornene-2-carboxylic acid 1- (1-adama) Chill) -1-methylethyl and the like.

  When the resin (A) includes a structural unit derived from the monomer represented by the formula (a-3), the content is usually 10 to 95 mol% with respect to all the structural units of the resin (A). , Preferably it is 15-90 mol%, More preferably, it is 20-85 mol%.

式（ａ−４）において、Ｒ^１０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Ｃ_１〜Ｃ₆アルキル基を表す。
Ｒ^１１は、それぞれ独立に、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。
ｈは０〜４の整数を表す。ｈが２以上の整数である場合、複数のＲ^１１は同一の種類の基であっても異なる種類の基であってもよい。
Ｒ^１２及びＲ^１３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^４は、単結合又は置換基を有していてもよい炭素数１〜１７の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる−ＣＨ_２−は−ＣＯ−、−Ｏ−、−Ｓ−、−ＳＯ_２−又は−Ｎ（Ｒ^ｃ）−で置き換わっていてもよい。Ｒ^ｃは、水素原子又は炭素数１〜６の脂肪族炭化水素基を表す。
Ｙ^４は、炭素数１〜１２の脂肪族炭化水素基、炭素数３〜１８の飽和環状炭化水素基又は炭素数６〜１８の芳香族炭化水素基であり、該脂肪族炭化水素基、飽和環状炭化水素基及び芳香族炭化水素基は、置換基を有していてもよい。 Examples of the monomer having an acid labile group and a carbon-carbon double bond include a monomer represented by the formula (a-4).

In formula (a-4), R ¹⁰ represents a hydrogen atom, a halogen atom, or a C ₁ -C ₆ alkyl group that may have a halogen atom.
R ¹¹ each independently represents 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, Represents an acryloyl group or a methacryloyl group.
h represents an integer of 0 to 4. When h is an integer of 2 or more, the plurality of R ¹¹ may be the same type of group or different types of groups.
R ¹² and R ¹³ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms.
X ⁴ represents a single bond or a divalent saturated hydrocarbon group having 1 to 17 carbon atoms which may have a substituent, and —CH ₂ — contained in the saturated hydrocarbon group is —CO—, — O—, —S—, —SO ₂ — or —N (R ^c ) — may be substituted. R ^c represents a hydrogen atom or an aliphatic hydrocarbon group having 1 to 6 carbon atoms.
Y ⁴ is an aliphatic hydrocarbon group having 1 to 12 carbon atoms, a saturated cyclic hydrocarbon group having 3 to 18 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms, and the aliphatic hydrocarbon group, saturated The cyclic hydrocarbon group and the aromatic hydrocarbon group may have a substituent.

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, perbromomethyl group, periodomethyl group and the like.
Examples of the substituent such as an alkyl group and an alkoxy group are the same as those described above.
Examples of the acyl group include an acetyl group, a propionyl group, and a butyryl group.
Examples of the acyloxy group include an acetyloxy group, a propionyloxy group, and a butyryloxy group.

The alkyl group in R ¹⁰ and R ¹¹ in formula (a-4) is preferably an alkyl group having 1 to 4 carbon atoms, more preferably an alkyl group having 1 to 2 carbon atoms, and particularly preferably a methyl group.
As the alkoxy group for R ^11, an alkoxy group having 1 to 4 carbon atoms is preferable, an alkoxy group having 1 to 2 carbon atoms is more preferable, and a methoxy group is particularly preferable.
Examples of the substituent that may be substituted on the group of X ⁴ and Y ⁴ include a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and an acyl having 2 to 4 carbon atoms. Group, an acyloxy group having 2 to 4 carbon atoms, and the like. Of these, a hydroxy group is preferable.

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

  When the resin (A) contains a structural unit derived from the monomer represented by the formula (a-4), the content is usually 10 to 95 mol% with respect to all the structural units of the resin (A). , Preferably it is 15-90 mol%, More preferably, it is 20-85 mol%.

<Other acid labile monomers>
Furthermore, other monomers that derive other structural units having an acid labile group and a carbon-carbon double bond in the molecule may be used.
Examples of such a monomer include the following monomers.

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

The resin (A) is preferably a co-polymerization of a monomer (a1) having an acid labile group and a monomer having no acid labile group (hereinafter sometimes referred to as “acid stable monomer”). It is a coalescence. An acid stable monomer may be used individually by 1 type, and may use 2 or more types together.
When the resin (A) is a copolymer of a monomer (a1) having an acid labile group and an acid stable monomer, the content of structural units derived from the monomer (a1) having an acid labile group Is preferably 10 to 80 mol%, more preferably 20 to 60 mol%, based on all structural units of the resin (A). The content of the structural unit derived from the monomer having an adamantyl group (particularly the monomer (a1) having an acid labile group) is 15 mol% or more based on the monomer (a1) having an acid labile group. It is preferable to do. When the ratio of the monomer having an adamantyl group is increased, the dry etching resistance of the resist is improved.

  As the acid stable monomer, those having a hydroxy group (b) or a lactone ring (c) are preferable. If a resin having a structural unit derived from an acid-stable monomer having a hydroxy group or an acid-stable monomer containing a lactone ring is used, the resolution of the resist and the adhesion to the substrate can be improved.

<Acid-stable monomer having hydroxy group (b)>
When the resist composition is used for KrF excimer laser exposure (248 nm), irradiation with high energy rays such as an electron beam or EUV light, an acid stable compound having a phenolic hydroxyl group, which is a hydroxystyrene, as an acid stable monomer having a hydroxy group It is preferable to use the monomer (b-1). When used for short wavelength ArF excimer laser exposure (193 nm) or the like, it is preferable to use an acid stable monomer having a hydroxyadamantyl group represented by the formula (b-2) as the acid stable monomer having a hydroxy group. . The acid stable monomer having a hydroxy group may be used alone or in combination of two or more.

式（ｂ−１）において、
Ｒ^１４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^１５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。
ｂは０〜４の整数を表す。ｂが２以上の整数である場合、複数のＲ^１５は互いに同一であっても異ってもよい。 Examples of the monomer having a phenolic hydroxy group include styrene monomers such as p- or m-hydroxystyrene represented by the formula (b-1).

In formula (b-1),
R ¹⁴ represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom.
R ¹⁵ 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.
b represents an integer of 0 to 4. If b is an integer of 2 or more, plural R ¹⁵ may be said even identical to each other.

As the alkyl group for R ^14, an alkyl group having 1 to 4 carbon atoms is preferable, an alkyl group having 1 to 2 carbon atoms is more preferable, and a methyl group is particularly preferable.
Moreover, as an alkoxy group, a C1-C4 alkoxy group is preferable, a C1-C2 alkoxy group is more preferable, and a methoxy group is especially preferable.

A copolymer resin having a structural unit derived from the monomer (b-1) having such a phenolic hydroxy group is copolymerized with acetyloxystyrenes corresponding to those obtained by replacing the phenolic hydroxy group with an acetyloxy group. The monomer can be produced by radical polymerization and deacetylation with an acid.
Examples of the monomer (b-1) having a phenolic hydroxy group include the following monomers. Of these, 4-hydroxystyrene or 4-hydroxy-α-methylstyrene is particularly preferable.

  When the resin (A) includes a structural unit derived from the monomer represented by the formula (b-1), the content is usually 5 to 90 mol% with respect to all the structural units of the resin (A). , Preferably it is 10-85 mol%, More preferably, it is 15-80 mol%.

  Examples of the acid stable monomer having a hydroxyadamantyl group include a monomer represented by the formula (b-2).

式（ｂ−２）において、Ｍ^２は、−Ｏ−又は−Ｏ−（ＣＨ₂）_k−ＣＯ−Ｏ−を表し、ｋは１〜７の整数を表す。
Ｒ^１６は、水素原子又はメチル基を表す。
Ｒ^１７及びＲ^１８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。
ｃは、０〜１０の整数を表す。

In formula (b-2), M ² represents —O— or —O— (CH ₂ ) _k —CO—O—, and k represents an integer of 1 to 7.
R ¹⁶ represents a hydrogen atom or a methyl group.
R ¹⁷ and R ¹⁸ each independently represents a hydrogen atom, a methyl group or a hydroxy group.
c represents an integer of 0 to 10.

M ² is preferably —O—, —O— (CH ₂ ) _f —CO—O— (wherein f is an integer of 1 to 4), and more preferably —O—.
R ¹⁶ is preferably a methyl group.
R ¹⁷ is preferably a hydrogen atom.
R ¹⁸ is preferably a hydrogen atom or a hydroxy group.
c is preferably an integer of 0 to 3, more preferably 0 or 1.

  Examples of the acid stable monomer having a hydroxyadamantyl group include the following. Among them, 3-hydroxyadamantan-1-yl (meth) acrylate, 3,5-dihydroxyadamantan-1-yl (meth) acrylate and (meth) acrylic acid 1- (3,5-dihydroxyadamantan-1-yloxycarbonyl ) Methyl is preferred, 3-hydroxyadamantan-1-yl (meth) acrylate and 3,5-dihydroxyadamantan-1-yl (meth) acrylate are more preferred, 3-hydroxyadamantan-1-yl methacrylate and 3,5- More preferred is dihydroxyadamantan-1-yl methacrylate.

  When the resin (A) includes a structural unit derived from the monomer represented by the formula (b-2), the content is usually 3 to 40 mol% with respect to all the structural units of the resin (A). , Preferably it is 5-35 mol%, More preferably, it is 5-30 mol%, More preferably, it is 5-20 mol%. It is preferable that the content of the structural unit derived from the monomer represented by the formula (b-2) is within the above range because a focus margin tends to be wide when forming a resist pattern.

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

  The acid-stable monomer having a lactone ring is represented by, for example, the formula (c-1), the formula (c-2), or the formula (c-3). These 1 type may be used independently and may use 2 or more types together.

式（ｃ−１）〜式（ｃ−３）において、
Ｍ^２は、それぞれ独立に、−Ｏ−又は−Ｏ−（ＣＨ₂）_k−ＣＯ−Ｏ−を表し、ｋは１〜７の整数を表す。
Ｒ^１９は、それぞれ独立に、水素原子又はメチル基を表す。
Ｒ^２０は、炭素数１〜４の脂肪族炭化水素基を表し、
Ｒ^２１及びＲ^２２は、それぞれ独立に、カルボキシ基、シアノ基又は炭素数１〜４の脂肪族炭化水素基を表す。
ｄは０〜５の整数を表す。
ｅ及びｇは、それぞれ独立に０〜３の整数を表す。
ｄ、ｅ又はｇが２以上のとき、それぞれ、複数のＲ^２０、Ｒ^２１又はＲ^２２は、互いに同一でも異なってもよい。

In Formula (c-1)-Formula (c-3),
M ² each independently, -O- or _{-O- (CH 2) k -CO-} O- the stands, k is an integer of 1-7.
R ¹⁹ each independently represents a hydrogen atom or a methyl group.
R ²⁰ represents an aliphatic hydrocarbon group having 1 to 4 carbon atoms,
R ²¹ and R ²² each independently represent a carboxy group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
d represents an integer of 0 to 5.
e and g each independently represent an integer of 0 to 3.
When d, e, or g is 2 or more, the plurality of R ²⁰ , R ^21, or R ²² may be the same as or different from each other.

M ² is each independently preferably —O—, —O— (CH ₂ ) _f —CO—O— (wherein f is an integer of 1 to 4), more preferably —O—. It is. However, —O— and the like listed for M ² mean that they are bonded to —CO— in the formula (c-1) to the formula (c-3) on the left side and to the lactone ring on the right side.
R ¹⁹ is preferably a methyl group.
R ²⁰ is preferably a methyl group.
R ²¹ and R ²² are preferably each independently a carboxy group, a cyano group or a methyl group.
d, e and g are each independently preferably 0 to 2, more preferably 0 or 1.

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

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

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

Among acid stable monomers having a lactone ring (c), (meth) acrylic acid (5-oxo-4-oxatricyclo [4.2.1.0 ^3,7 ] nonan-2-yl, (meth) acrylic Acid tetrahydro-2-oxo-3-furyl, 2- (5-oxo-4-oxatricyclo [4.2.1.0 ^3,7 ] nonan-2-yloxy) -2-oxoethyl (meth) acrylate Are preferred, and those in the form of methacrylate are more preferred.

When the resin (A) includes a structural unit derived from the monomer represented by the formula (c-1), the formula (c-2) or the formula (c-3), the content thereof is the total of the resin (A). It is 5-50 mol% normally with respect to a structural unit, Preferably it is 10-45 mol%, More preferably, it is 15-40 mol%.
When the resin (A) includes a structural unit derived from an acid-stable monomer having a lactone ring (c), the total content is usually 5 to 60 mol% with respect to all the structural units of the resin (A). , Preferably 15 to 55 mol%.

<Other acid stable monomers>
Other acid stable monomers include, for example, maleic anhydride represented by formula (d-1), itaconic anhydride represented by formula (d-2), or norbornene ring represented by formula (d-3) And acid-stable monomers having

式中、Ｒ²³及びＲ²⁴は、それぞれ独立に、水素原子、置換基（例えば、ヒドロキシ基）を有していてもよい炭素数１〜３の脂肪族炭化水素基、シアノ基、カルボキシ基又は基−ＣＯＯＲ²⁵を表すか、Ｒ²³及びＲ²⁴は互いに結合して−ＣＯ−Ｏ−ＣＯ−を形成し、Ｒ²⁵は、炭素数１〜３６の脂肪族炭化水素基又は炭素数３〜３６の飽和環状炭化水素基を表し、該脂肪族炭化水素基及び該飽和環状炭化水素基の−ＣＨ_２−は、−Ｏ−又は−ＣＯ−で置き換わっていてもよい。但し−ＣＯＯＲ²⁵が酸不安定基となるものは除く（即ちＲ²⁵は、第三級炭素原子が−Ｏ−と結合するものを含まない）。

In the formula, each of R ²³ and R ²⁴ independently represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 3 carbon atoms which may have a substituent (for example, a hydroxy group), a cyano group, a carboxy group, or or represents a group -COOR ^25, R ²³ and R ²⁴ are bonded to each other to form a -CO-O-CO-, R ²⁵ is an aliphatic hydrocarbon group or a carbon of 1 to 36 carbon atoms 3-36 In the saturated cyclic hydrocarbon group, —CH ₂ — in the aliphatic hydrocarbon group and the saturated cyclic hydrocarbon group may be replaced by —O— or —CO—. However, those in which —COOR ²⁵ becomes an acid labile group are excluded (that is, R ²⁵ does not include those in which a tertiary carbon atom is bonded to —O—).

Examples of the aliphatic hydrocarbon group optionally having a substituent for R ²³ and R ²⁴ include a methyl group, an ethyl group, a propyl group, a hydroxymethyl group, and a 2-hydroxyethyl group.
The aliphatic hydrocarbon group for R ²⁵ preferably has 1 to 8 carbon atoms, more preferably 1 to 6 carbon atoms, and the saturated cyclic hydrocarbon group preferably has 4 to 36 carbon atoms, more preferably 4 carbon atoms. ~ 12. Examples of R ²⁵ include a methyl group, an ethyl group, a propyl group, a 2-oxo-oxolan-3-yl group, and a 2-oxo-oxolan-4-yl group.

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

  When the resin includes a structural unit derived from the monomer represented by the formula (d-1), the formula (d-2), or the formula (d-3), the content is based on all the structural units of the resin (A). On the other hand, it is 2-40 mol% normally, Preferably it is 3-30 mol%, More preferably, it is 5-20 mol%.

  A preferred resin (A) is a copolymer obtained by polymerizing at least a monomer (a) having an acid labile group, an acid stable monomer (b) having a hydroxy group, and / or an acid stable monomer having a lactone ring (c). It is a polymer. In this preferred copolymer, the monomer (a) having an acid labile group is more preferably at least one of a monomer (a-1) having an adamantyl group and a monomer (a-2) having a cyclohexyl group. A species (more preferably a monomer (a-1) having an adamantyl group), and an acid-stable monomer (b) having a hydroxy group, preferably an acid-stable monomer (b-2) having a hydroxyadamantyl group, and a lactone The acid-stable monomer having a ring (c) is more preferably an acid-stable monomer (c-1) having a γ-butyrolactone ring and an acid-stable monomer (c-2) having a condensed ring of a γ-butyrolactone ring and a norbornane ring At least one of the following.

Resin (A) can be manufactured by a well-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, more preferably 3,500 or more), 50,000 or less (more preferably 30,000 or less, and further preferably Is 10,000 or less).

  It is preferable that content of resin (A) is 80 to 99 mass% in solid content of a composition. In the present specification, the “solid content in the composition” means the total of the composition components excluding the solvent. The solid content in the composition and the content of the resin (A) relative thereto can be measured by known analytical means such as liquid chromatography or gas chromatography.

<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 content of the basic compound (C) is preferably about 0.01 to 1% by mass based on the solid content of the resist composition.

  The basic compound (C) is preferably a basic nitrogen-containing organic compound (for example, amine and ammonium salt). The amine may be an aliphatic amine or an aromatic amine. As the aliphatic amine, any of primary amine, secondary amine and tertiary amine can be used. The aromatic amine may be either an aromatic ring such as aniline bonded with an amino group or a heteroaromatic amine such as pyridine. Preferable basic compound (C) includes an aromatic amine represented by the formula (C2), particularly an aniline represented by the formula (C2-1).

式（Ｃ２）及び式（Ｃ２−１）において、
Ａｒは、芳香族炭化水素基を表す。
Ｔ^１及びＴ^２は、それぞれ独立に、水素原子、脂肪族炭化水素基（好ましくは、アルキル基）、飽和環状炭化水素基（好ましくは、シクロアルキル基）、芳香族炭化水素基を表す。該脂肪族炭化水素基、該飽和環状炭化水素基又は該芳香族炭化水素基に含まれる水素原子は、ヒドロキシ基、アミノ基又は炭素数１〜６のアルコキシ基で置換されていてもよく、該アミノ基は、炭素数１〜４のアルキル基で置換されていてもよい。
Ｔ^３は、脂肪族炭化水素基（好ましくは、アルキル基）、アルコキシ基、飽和環状炭化水素基（好ましくは、シクロアルキル基）、芳香族炭化水素基を表す。該脂肪族炭化水素基、該アルコキシ基、該飽和環状炭化水素基及び該芳香族炭化水素基に含まれる水素原子は、上記と同様の基で置換されていてもよい。
ｏは０〜３の整数を表す。ｏが２以上のとき、複数のＴ^３は、互いに同一でも異なってもよい。

In formula (C2) and formula (C2-1),
Ar represents an aromatic hydrocarbon group.
T ¹ and T ² each independently represent a hydrogen atom, an aliphatic hydrocarbon group (preferably an alkyl group), a saturated cyclic hydrocarbon group (preferably a cycloalkyl group), or an aromatic hydrocarbon group. The hydrogen atom contained in the aliphatic hydrocarbon group, the saturated cyclic hydrocarbon group or the aromatic hydrocarbon group may be substituted with a hydroxy group, an amino group or an alkoxy group having 1 to 6 carbon atoms, The amino group may be substituted with an alkyl group having 1 to 4 carbon atoms.
T ³ represents an aliphatic hydrocarbon group (preferably an alkyl group), an alkoxy group, a saturated cyclic hydrocarbon group (preferably a cycloalkyl group), or an aromatic hydrocarbon group. The hydrogen atom contained in the aliphatic hydrocarbon group, the alkoxy group, the saturated cyclic hydrocarbon group and the aromatic hydrocarbon group may be substituted with the same group as described above.
o represents an integer of 0 to 3. When o is 2 or more, the plurality of T ³ may be the same as or different from each other.

In Formula (C2) and Formula (C2-1), the aliphatic hydrocarbon group preferably has about 1 to 6 carbon atoms.
The saturated cyclic hydrocarbon group preferably has about 5 to 10 carbon atoms.
The aromatic hydrocarbon group preferably has about 6 to 10 carbon atoms.
The alkoxy group preferably has about 1 to 6 carbon atoms.

Examples of the aromatic amine (C2) include 1-naphthylamine and 2-naphthylamine.
Examples of aniline (C2-1) include aniline, diisopropylaniline, 2-, 3- or 4-methylaniline, 4-nitroaniline, N-methylaniline, N, N-dimethylaniline, diphenylamine and the like. Among these, diisopropylaniline (particularly 2,6-diisopropylaniline) is preferable.

式（Ｃ３）〜式（Ｃ１１）において、
Ｔ^１、Ｔ^２、Ｔ^３及びｏは、上記と同じ意味である。
Ｔ^４は、それぞれ独立に、脂肪族炭化水素基、飽和環状炭化水素基又はアルカノイル基を表す。脂肪族炭化水素基は、好ましくは炭素数１〜６程度であり、飽和環状炭化水素基は、好ましくは炭素数３〜６程度であり、アルカノイル基は、好ましくは炭素数２〜６程度である。
ｕは０〜８の整数を示す。ｏ又はｕが２以上の整数であるとき、複数のＴ^３又はＴ^４は、それぞれ互いに同一でも異なってもよい。
Ａは、それぞれ独立に、２価の脂肪族炭化水素基（好ましくはアルキレン基）、−ＣＯ−、−Ｃ（＝ＮＨ）−、−Ｃ（＝ＮＲ³⁶）−、−Ｓ−、−Ｓ−Ｓ−又はこれらの組合せを表す。２価の脂肪族炭化水素基は、好ましくは炭素数１〜６程度である。Ｒ³⁶は、炭素数１〜４のアルキル基を表す。
ここで、アルカノイル基としては、例えば、アセチル基、エチルカルボニル基、ヘプチルカルボニル基等が挙げられる。 Moreover, as a basic compound (C), the compound represented by Formula (C3)-Formula (C11) is mentioned.

In Formula (C3) to Formula (C11),
T ¹ , T ² , T ³ and o have the same meaning as above.
T ⁴ each independently represents an aliphatic hydrocarbon group, a saturated cyclic hydrocarbon group or an alkanoyl group. The aliphatic hydrocarbon group preferably has about 1 to 6 carbon atoms, the saturated cyclic hydrocarbon group preferably has about 3 to 6 carbon atoms, and the alkanoyl group preferably has about 2 to 6 carbon atoms. .
u represents an integer of 0 to 8. When o or u is an integer of 2 or more, the plurality of T ³ or T ⁴ may be the same as or different from each other.
A is each independently a divalent aliphatic hydrocarbon group (preferably an alkylene group), —CO—, —C (═NH) —, —C (═NR ³⁶ ) —, —S—, —S—. S—or a combination thereof. The divalent aliphatic hydrocarbon group preferably has about 1 to 6 carbon atoms. R ³⁶ represents an alkyl group having 1 to 4 carbon atoms.
Here, examples of the alkanoyl group include an acetyl group, an ethylcarbonyl group, and a heptylcarbonyl group.

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

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

<Solvent (sometimes referred to as "solvent (E)")>
The resist composition of the present invention may contain a solvent (E). The resist composition of the present invention containing the solvent (E) is suitable for producing a thin film resist.
The content of the solvent (E) is 90% by mass or more (preferably 92% by mass or more, more preferably 94% by mass or more) and 99.9% by mass or less (preferably 99% by mass or less) in the composition. The content of the solvent (E) can be measured by a known analysis means such as liquid chromatography or gas chromatography.

  Examples of the solvent (E) include glycol ether esters such as ethyl cellosolve acetate, methyl cellosolve acetate and propylene glycol monomethyl ether acetate; glycol ethers such as propylene glycol monomethyl ether; ethyl lactate, butyl acetate, amyl acetate and And esters such as ethyl pyruvate; ketones such as acetone, methyl isobutyl ketone, 2-heptanone and cyclohexanone; cyclic esters such as γ-butyrolactone; A solvent (E) may be used individually by 1 type, and may use 2 or more types together.

<Other components (hereinafter sometimes referred to as “other components (F)”)>
The resist composition of this invention may contain the other component (F) as needed. The component (F) is not particularly limited, and additives known in the resist field, for example, sensitizers, dissolution inhibitors, surfactants, stabilizers, dyes and the like can be used.

<Method for producing resist pattern>
The method for producing a resist pattern of the present invention comprises:
(1) The process of apply | coating the resist composition of this invention mentioned above on a board | substrate,
(2) The process of drying the composition after application | coating and forming a composition layer,
(3) a step of exposing the composition layer using an exposure machine;
(4) A step of heating the composition layer after exposure,
(5) The process which develops the composition layer after a heating using a image development apparatus is included.

  Application of the resist composition onto the substrate can be performed by a commonly used apparatus such as a spin coater.

Drying is performed, for example, by evaporating and removing volatile components such as a solvent using a heating device such as a hot plate (so-called pre-baking), or by using a decompression device, and drying the composition layer. Form. As for the temperature in this case, about 50-200 degreeC is illustrated, for example. The pressure is exemplified by about 1 to 1.0 × 10 ⁵ Pa.

The obtained composition layer is usually exposed using an exposure machine. At this time, an immersion exposure machine may be used. Usually, exposure is performed through a mask corresponding to a required pattern. Exposure light sources include those that emit laser light in the ultraviolet region such as KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), F ₂ excimer laser (wavelength 157 nm), solid-state laser light source (YAG or semiconductor laser) Etc.) can be used such as those that convert the wavelength of the laser light from the above and radiate the harmonic laser light in the far ultraviolet region or the vacuum ultraviolet region. The exposure machine may irradiate an electron beam or extreme ultraviolet light (EUV).

The composition layer after exposure is subjected to heat treatment (so-called post-exposure baking) in order to promote the deprotection group reaction. As heating temperature, it is about 50-200 degreeC normally, Preferably it is about 70-150 degreeC.
The heated composition layer is usually developed using an alkali developer using a developing device.
The alkaline developer used here may be various alkaline aqueous solutions used in this field. Examples thereof include an aqueous solution of tetramethylammonium hydroxide and (2-hydroxyethyl) trimethylammonium hydroxide (commonly called choline).
After development, it is preferable to rinse with ultrapure water to remove water remaining on the substrate and the pattern.

<Application>
The resist composition of the present invention is particularly useful for a chemically amplified photoresist composition, and is used in a wide range of applications such as semiconductor microfabrication, production of circuit boards such as liquid crystals and thermal heads, and other photofabrication processes. Can be suitably used. In particular, it can be used as a chemically amplified photoresist composition suitable for excimer laser lithography such as ArF and KrF, ArF excimer laser immersion exposure lithography, electron beam (EB) exposure lithography, and EUV exposure lithography. It can also be used for dry exposure. Furthermore, it can be used for double imaging and is industrially useful.

Hereinafter, the present invention will be described in detail by way of examples. In the examples,% and parts representing the content and the amount used are based on mass unless otherwise specified.
In the examples, the structure of the compound was confirmed by mass spectrometry (LC; Agilent 1100 type, MASS; Agilent LC / MSD type).
The weight average molecular weight is a value determined by gel permeation chromatography (HLC-8120GPC type manufactured by Tosoh Corporation, three columns are “TSKgel Multipore HXL-M”, and the solvent is tetrahydrofuran) using polystyrene as a standard product.
Column: TSKgel Multipore H _XL -M x 3 + guardcolumn (manufactured by Tosoh Corporation)
Eluent: Tetrahydrofuran Flow rate: 1.0 mL / min
Detector: RI detector Column temperature: 40 ° C
Injection volume: 100 μl
Molecular weight standard: Standard polystyrene (manufactured by Tosoh Corporation)

式（Ｂ１−１）で表される塩を、特開２００８−１２７３６７号公報に記載された方法で合成した。
式（Ｂ１−１）で表される塩１０．００部及びアセトニトリル６０．００部を仕込み、４０℃で３０分間攪拌し、式（Ｂ１−２）で表される化合物４．４４部を仕込み、５０℃で１時間攪拌することにより、式（Ｂ１−３）で表される化合物を含む溶液を得た。得られた式（Ｂ１−３）で表される化合物を含む溶液に、式（Ｂ１−４）で表される化合物２．６３部を仕込み、２３℃で１時間攪拌した。得られた反応マスに、クロロホルム８０部及びイオン交換水３０部を仕込み、攪拌、分液を行った。水洗を５回行った。得られた有機層に活性炭１．００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２５部を添加して溶解し、濃縮した。得られた残渣にｔｅｒｔ−ブチルメチルエーテル３０部を加えて攪拌し、３０分間攪拌し、ろ過することにより、式（Ｂ１）で表される塩４．４８部を得た。 Example 1: Synthesis of a salt represented by the formula (B1)

The salt represented by the formula (B1-1) was synthesized by the method described in JP 2008-127367 A.
10.00 parts of the salt represented by the formula (B1-1) and 60.00 parts of acetonitrile were charged, stirred at 40 ° C. for 30 minutes, and 4.44 parts of the compound represented by the formula (B1-2) were charged. By stirring at 50 degreeC for 1 hour, the solution containing the compound represented by Formula (B1-3) was obtained. To the obtained solution containing the compound represented by the formula (B1-3), 2.63 parts of the compound represented by the formula (B1-4) was charged and stirred at 23 ° C. for 1 hour. The obtained reaction mass was charged with 80 parts of chloroform and 30 parts of ion-exchanged water, and 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 25 parts of acetonitrile was added to the resulting concentrate to dissolve and concentrate. To the obtained residue, 30 parts of tert-butyl methyl ether was added, stirred, stirred for 30 minutes, and filtered to obtain 4.48 parts of the salt represented by the formula (B1).

Identification of the salt represented by the formula (B1);
MS (ESI (+) Spectrum): M ⁺ 263.1
MS (ESI (-) Spectrum): M ^- 272.0

式（Ｂ１−１）で表される塩を、特開２００８−１２７３６７号公報に記載された方法で合成した。
式（Ｂ１−１）で表される塩１０．００部及びアセトニトリル６０．００部を仕込み、４０℃で３０分間攪拌し、式（Ｂ１−２）で表される化合物４．４４部を仕込み、５０℃で１時間攪拌することにより、式（Ｂ１−３）で表される化合物を含む溶液を得た。得られた式（Ｂ１−３）で表される化合物を含む溶液に、式（Ｂ２−４）で表される化合物２．９５部を仕込み、２３℃で１時間攪拌した。得られた反応マスに、クロロホルム８０部及びイオン交換水３０部を仕込み、攪拌、分液を行った。水洗を５回行った。得られた有機層に活性炭１．００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部を添加して溶解し、濃縮した。得られた残渣にｔｅｒｔ−ブチルメチルエーテル４０部を加えて攪拌し、３０分間攪拌し、ろ過することにより、式（Ｂ２）で表される塩４．０９部を得た。 Example 2: Synthesis of a salt represented by the formula (B2)

The salt represented by the formula (B1-1) was synthesized by the method described in JP 2008-127367 A.
10.00 parts of the salt represented by the formula (B1-1) and 60.00 parts of acetonitrile were charged, stirred at 40 ° C. for 30 minutes, and 4.44 parts of the compound represented by the formula (B1-2) were charged. By stirring at 50 degreeC for 1 hour, the solution containing the compound represented by Formula (B1-3) was obtained. To the obtained solution containing the compound represented by the formula (B1-3), 2.95 parts of the compound represented by the formula (B2-4) was charged and stirred at 23 ° C. for 1 hour. The obtained reaction mass was charged with 80 parts of chloroform and 30 parts of ion-exchanged water, and 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 the resulting concentrate was dissolved by adding 30 parts of acetonitrile and concentrated. To the obtained residue, 40 parts of tert-butyl methyl ether was added, stirred, stirred for 30 minutes, and filtered to obtain 4.09 parts of the salt represented by the formula (B2).

Identification of the salt represented by the formula (B2);
MS (ESI (+) Spectrum): M ⁺ 263.1
MS (ESI (-) Spectrum): M ^- 314.1

式（Ｂ１−１）で表される塩を、特開２００８−１２７３６７号公報に記載された方法で合成した。
式（Ｂ１−１）で表される塩１０．００部及びアセトニトリル６０．００部を仕込み、４０℃で３０分間攪拌し、式（Ｂ１−２）で表される化合物４．４４部を仕込み、５０℃で１時間攪拌することにより、式（Ｂ１−３）で表される化合物を含む溶液を得た。得られた式（Ｂ１−３）で表される化合物を含む溶液に、式（Ｂ２−４）で表される化合物３．２２部を仕込み、２３℃で１時間攪拌した。得られた反応マスに、クロロホルム８０部及びイオン交換水３０部を仕込み、攪拌、分液を行った。水洗を５回行った。得られた有機層に活性炭１．００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部を添加して溶解し、濃縮した。得られた残渣にｔｅｒｔ−ブチルメチルエーテル５０部を加えて攪拌し、３０分間攪拌し、ろ過することにより、式（Ｂ３）で表される塩７．７９部を得た。 Example 3: Synthesis of a salt represented by the formula (B3)

The salt represented by the formula (B1-1) was synthesized by the method described in JP 2008-127367 A.
10.00 parts of the salt represented by the formula (B1-1) and 60.00 parts of acetonitrile were charged, stirred at 40 ° C. for 30 minutes, and 4.44 parts of the compound represented by the formula (B1-2) were charged. By stirring at 50 degreeC for 1 hour, the solution containing the compound represented by Formula (B1-3) was obtained. To the obtained solution containing the compound represented by the formula (B1-3), 3.22 parts of the compound represented by the formula (B2-4) was charged and stirred at 23 ° C. for 1 hour. The obtained reaction mass was charged with 80 parts of chloroform and 30 parts of ion-exchanged water, and 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 the resulting concentrate was dissolved by adding 30 parts of acetonitrile and concentrated. To the obtained residue, 50 parts of tert-butyl methyl ether was added, stirred, stirred for 30 minutes, and filtered to obtain 7.79 parts of the salt represented by the formula (B3).

Identification of the salt represented by the formula (B3);
MS (ESI (+) Spectrum): M ⁺ 263.1
MS (ESI (-) Spectrum): M ^- 298.1

式（Ｂ１−１）で表される塩を、特開２００８−１２７３６７号公報に記載された方法で合成した。
式（Ｂ１−１）で表される塩１０．００部及びアセトニトリル６０．００部を仕込み、４０℃で３０分間攪拌し、式（Ｂ１−２）で表される化合物４．４４部を仕込み、５０℃で１時間攪拌することにより、式（Ｂ１−３）で表される化合物を含む溶液を得た。得られた式（Ｂ１−３）で表される化合物を含む溶液に、式（Ｂ２−４）で表される化合物４．５９部を仕込み、２３℃で１時間攪拌した。得られた反応マスに、クロロホルム８０部及びイオン交換水３０部を仕込み、攪拌、分液を行った。水洗を５回行った。得られた有機層に活性炭１．００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部を添加して溶解し、濃縮した。得られた残渣にｔｅｒｔ−ブチルメチルエーテル５０部を加えて攪拌し、３０分間攪拌し、ろ過することにより、式（Ｂ４）で表される塩６．８６部を得た。 Example 4: Synthesis of salt represented by formula (B4)

The salt represented by the formula (B1-1) was synthesized by the method described in JP 2008-127367 A.
10.00 parts of the salt represented by the formula (B1-1) and 60.00 parts of acetonitrile were charged, stirred at 40 ° C. for 30 minutes, and 4.44 parts of the compound represented by the formula (B1-2) were charged. By stirring at 50 degreeC for 1 hour, the solution containing the compound represented by Formula (B1-3) was obtained. To the obtained solution containing the compound represented by the formula (B1-3), 4.59 parts of the compound represented by the formula (B2-4) was charged and stirred at 23 ° C. for 1 hour. The obtained reaction mass was charged with 80 parts of chloroform and 30 parts of ion-exchanged water, and 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 the resulting concentrate was dissolved by adding 30 parts of acetonitrile and concentrated. To the obtained residue, 50 parts of tert-butyl methyl ether was added and stirred, stirred for 30 minutes, and filtered to obtain 6.86 parts of the salt represented by the formula (B4).

Identification of the salt represented by the formula (B4);
MS (ESI (+) Spectrum): M ⁺ 263.1
MS (ESI (-) Spectrum): M ^- 358.1

式（Ｂ５−１）で表される化合物５０．００部及びテトラヒドロフラン２５０部を、反応器中に仕込み、３０℃で３０分間攪拌し、トリメチルシリルクロリド５０．２３部を滴下した。得られた混合液を０℃まで冷却し、式（Ｂ５−２）で表される化合物（純度３２％ 東京化成製）１５７．２０部を３０分かけて滴下した。さらに、これを２３℃まで昇温し、同温度で１時間攪拌した。得られた反応混合物に、１Ｎ塩酸１２５部を仕込み、攪拌・静置し、分液することで水層を回収した。回収された水層に、ｔｅｒｔ−ブチルメチルエーテル１２５部を加えて攪拌・静置し、分液することで水層を回収した。回収された水層に、クロロホルム１２５部を加えて攪拌・静置し、分液することで有機層を回収した。回収された有機層をろ過し、得られたろ液を濃縮した。濃縮残渣に、アセトニトリル２８．３３部及びｔｅｒｔ−ブチルメチルエーテル３５４．１５部を仕込み、２３℃で３０分間攪拌し、析出した結晶をろ過することにより、式（Ｂ５−３）で表される化合物５３．００部を得た。

式（Ｂ５−４）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（Ｂ５−３）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、これを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、ろ過して、式（Ｂ５−５）で表される塩１４．２８部を得た。 Example 5: Synthesis of salt represented by formula (B5)

50.00 parts of the compound represented by the formula (B5-1) 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 (B5-2) (purity: 32%, manufactured by Tokyo Chemical Industry Co., Ltd.) was added dropwise over 30 minutes. Furthermore, this was heated up to 23 degreeC 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. The collected organic layer was filtered, and 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 (B5-3) 53.00 parts were obtained.

13.12 parts of a compound represented by the formula (B5-4) 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 (B5-3) 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 this was 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, stirred and filtered to obtain 14.28 parts of the salt represented by the formula (B5-5). Obtained.

  10.32 parts of the salt represented by the formula (B5-5) and 61.91 parts of acetonitrile were charged, and the mixture was stirred at 40 ° C. for 30 minutes, and 4.44 parts of the compound represented by the formula (B1-2) was charged. . By stirring this at 50 degreeC for 1 hour, the solution containing the compound represented by Formula (B5-6) was obtained. In a solution containing the compound represented by the formula (B5-6) thus obtained, 2.63 parts of the compound represented by the formula (B1-4) 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. The filtrate was concentrated, and the resulting concentrate was dissolved by adding 30 parts of acetonitrile and concentrated. To the obtained residue, 30 parts of tert-butyl methyl ether was added, stirred, stirred for 30 minutes, and filtered to obtain 10.81 parts of the salt represented by the formula (B5).

Identification of the salt represented by the formula (B5);
MS (ESI (+) Spectrum): M ⁺ 277.1
MS (ESI (-) Spectrum): M ^- 272.0

式（Ｂ６−１）で表される塩６．０３部及びアセトニトリル３０．００部を仕込み、２３℃で３０分間攪拌した。その後、式（Ｂ１−２）で表される化合物１．７０部を添加し、６０℃で１時間攪拌した。得られた反応溶液をろ過し、回収されたろ液を濃縮した。得られた濃縮物に、クロロホルム３０部及びイオン交換水１５部を加え、２３℃で３０分間攪拌した。その後、静置し、分液して有機層を得た。得られた有機層に、イオン交換水１５部を加え、２３℃で３０分間攪拌した。この水洗の操作をさらに３回行った。得られた有機層に活性炭１．００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、ｔｅｒｔ−ブチルメチルエーテル１００部を加えて攪拌し、ろ過することにより、式（Ｂ６−２）で表される塩６．１２部を得た。 Example 6: Synthesis of salt represented by formula (B6)

6.03 parts of a salt represented by the formula (B6-1) and 30.00 parts of acetonitrile were charged and stirred at 23 ° C. for 30 minutes. Thereafter, 1.70 parts of the compound represented by the formula (B1-2) was added, and the mixture was stirred at 60 ° C. for 1 hour. The obtained reaction solution was filtered, and the collected filtrate was concentrated. To the obtained concentrate, 30 parts of chloroform and 15 parts of ion-exchanged water were added and stirred at 23 ° C. for 30 minutes. Then, it left still and liquid-separated and obtained the organic layer. To the obtained organic layer, 15 parts of ion-exchanged water was added and stirred at 23 ° C. for 30 minutes. This washing operation was further performed 3 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, 100 parts of tert-butyl methyl ether was added to the resulting concentrate, and the mixture was stirred and filtered to obtain 6.12 parts of the salt represented by the formula (B6-2).

  Charge 8.00 parts of the compound represented by formula (B6-2), 48.00 parts of dimethylformamide and 1.60 parts of compound represented by formula (B1-4), and stir at 23 ° C. for 30 minutes. 0.24 part of potassium was charged and stirred at 23 ° C. for 2 hours. To the obtained reaction product, 100 parts of chloroform and 30.00 parts of ion-exchanged water were added, followed by stirring and liquid separation. Water washing was performed 6 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 20 parts of acetonitrile was added to the resulting concentrate to dissolve and concentrate. Thereafter, 50 parts of tert-butyl methyl ether was added thereto and stirred, and the supernatant was removed. The obtained residue was dissolved in chloroform and concentrated to obtain 4.88 parts of the salt represented by the formula (B6).

Identification of the salt represented by the formula (B6);
MS (ESI (+) Spectrum): M ⁺ 263.1
MS (ESI (−) Spectrum): M ⁻ 480.2

Example 7: Synthesis of salt represented by formula (B7)

  10.00 parts of the salt represented by the formula (B1-1) and 60.00 parts of acetonitrile were charged, stirred at 40 ° C. for 30 minutes, and 4.44 parts of the compound represented by the formula (B1-2) were charged. By stirring at 50 degreeC for 1 hour, the solution containing the compound represented by Formula (B1-3) was obtained. To the obtained solution containing the compound represented by the formula (B1-3), 2.95 parts of the compound represented by the formula (B7-1) was charged and stirred at 23 ° C. for 1 hour. The obtained reaction mass was charged with 80 parts of chloroform and 30 parts of ion-exchanged water, and 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 25 parts of acetonitrile was added to the resulting concentrate to dissolve and concentrate. To the obtained residue, 30 parts of tert-butyl methyl ether was added and stirred, stirred for 30 minutes, and filtered to obtain 7.48 parts of the salt represented by the formula (B7).

Identification of the salt represented by the formula (B7);
MS (ESI (+) Spectrum): M ⁺ 263.1
MS (ESI (-) Spectrum): M ^- 286.1

The monomers used in the resin synthesis are shown below.

Synthesis Example 1: Synthesis of Resin A1 Monomer E, monomer F, monomer B, monomer C and monomer D were charged in a molar ratio of 30: 14: 6: 20: 30. Subsequently, 1.5 mass times dioxane was added with respect to the total mass of all the monomers. 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. And heated at 73 ° C. for about 5 hours. Thereafter, the reaction solution is purified by performing the operation of pouring into a large amount of methanol / water mixed solvent (4: 1) and precipitating three times, and the weight average molecular weight is about 8.1 × 10 ^3. The coalescence was obtained with a yield of 65%. The obtained copolymer has a structural unit of the following formula, and this was designated as resin A1.

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

(Preparation of resist composition)
As shown in Table 1, a resist composition was prepared by filtering a mixture obtained by mixing and dissolving the following components through a fluororesin filter having a pore size of 0.2 μm.

酸発生剤Ｘ２：

<Resin>
Resins A1 to A2
<Acid generator>
Acid generator B1: salt represented by formula (B1) Acid generator B2: salt represented by formula (B2) Acid generator B3: salt represented by formula (B3) Acid generator B4: formula (B4) The acid generator B5: the salt represented by the formula (B5) The acid generator B6: the salt represented by the formula (B6) The acid generator B7: the salt represented by the formula (B7) Agent X1:

Acid generator X2:

<Basic compound: Quencher>
Quencher C1: 2,6-diisopropylaniline <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)
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. Next, the resist composition was spin-coated on the organic antireflection film so that the film thickness after drying (pre-baking) was 110 nm.
The obtained silicon wafer was pre-baked (PB) for 60 seconds on the direct hot plate at the temperature described in the “PB” column of Table 1. An ArF excimer laser stepper for immersion exposure [XT: 1900 Gi; manufactured by ASML, NA = 1.35, 2-poles on axis illumination (σout = 0.97, σin) = 0.77, Y-polarized light], the line and space pattern was subjected to immersion exposure by changing the exposure amount in stages, and ultrapure water was used as the immersion medium.
After the exposure, post-exposure baking (PEB) was performed on the hot plate at the temperature described in the “PEB” column of Table 1 for 60 seconds.
Further, paddle development was performed for 60 seconds with an aqueous 2.38 mass% tetramethylammonium hydroxide solution to obtain a resist pattern.

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

(Exposure margin evaluation (EL))
In the exposure range of effective sensitivity ± 10%, the exposure amount is plotted on the horizontal axis, and the line width of a 50 nm line pattern formed with the exposure amount is plotted on the vertical axis. The absolute value of the slope of the regression line obtained from the plot is
What is 1.1 nm / (mJ / cm ² ) or less, ◎,
The one below 1.3 nm / (mJ / cm ² ) ○
More than 1.3 nm / (mJ / cm ² ) and 1.5 nm / (mJ / cm ² ) or less Δ
What exceeded 1.5 nm / (mJ / cm < ² >) was set as x.

(Focus margin evaluation (DOF))
In the effective sensitivity, the resist pattern is formed by changing the focus stepwise, and the focus range (47.5-52.5 nm) in which the line width of the obtained resist pattern is 50 nm ± 5% is used as an index (DOF ). DOF
◎, more than 0.17μm
○ over 0.14μm
Δ over 0.09 μm and 0.14 μm or less
What was less than 0.14 micrometer was set as x.
These results are shown in Table 2.

  According to the resist composition of the present invention, the exposure margin (EL) and the focus margin (DOF) when forming a resist pattern are wide.

Claims (7)

A salt represented by the formula (I).

[In the formula (I),
R ¹ and R 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 —CH ₂ — contained in the divalent saturated hydrocarbon group may be replaced by —O— or —CO—. .
Ring W ¹ represents a heterocyclic ring having 2 to 36 carbon atoms.
R ³ represents a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, and —CH ₂ — contained in the hydrocarbon group may be replaced by —O— or —CO—.
R ⁴ each independently represents a hydrocarbon group having 1 to 6 carbon atoms, and —CH ₂ — contained in the hydrocarbon group may be replaced by —O— or —CO—.
m represents an integer of 0-6.
Z ⁺ represents an organic cation. ] The salt according to claim 1, wherein L ¹ is a group represented by the formula (L1-1).

[In Formula (L1-1), L ^b2 represents a single bond or a divalent saturated hydrocarbon group having 1 to 15 carbon atoms.
* Represents a bond with —C (R ¹ ) (R ² ) —. ] The salt according to claim 1 or 2, wherein Z ⁺ is a triarylsulfonium cation.   The acid generator containing the salt in any one of Claims 1-3. An acid generator containing a salt represented by the formula (I) and a resin, the resin having an acid labile group and insoluble or hardly soluble in an alkaline aqueous solution; A resist composition, which is a resin that can be dissolved in an alkaline aqueous solution by action.

[In the formula (I),
R ¹ and R 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 —CH ₂ — contained in the divalent saturated hydrocarbon group may be replaced by —O— or —CO—. .
Ring W ¹ represents a heterocyclic ring having 2 to 36 carbon atoms.
R ³ represents a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, and —CH ₂ — contained in the hydrocarbon group may be replaced by —O— or —CO—.
R ⁴ each independently represents a hydrocarbon group having 1 to 6 carbon atoms, and —CH ₂ — contained in the hydrocarbon group may be replaced by —O— or —CO—.
m represents an integer of 0-6.
Z ⁺ represents an organic cation.
However, the following compounds are excluded. ]

  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,
(5) A method for producing a resist pattern, comprising a step of developing the heated composition layer using a developing device.