KR101769153B1 - Salt and photoresist composition - Google Patents

Abstract

[식 중, R¹ 및 R² 는 서로 독립적으로, 불소 원자 또는 C₁∼C₆ 퍼플루오로알킬기를 나타낸다. X¹ 은 2 가의 C₁∼C₁₇ 포화 탄화수소기를 나타내고, 상기 2 가의 포화 탄화수소기에 함유되는 수소 원자는 불소 원자로 치환되어 있어도 되고, 상기 2 가의 포화 탄화수소기에 함유되는 -CH₂- 는, -O- 또는 -CO- 로 치환되어 있어도 된다. Z¹⁺ 는 유기 카운터 이온을 나타낸다] 로 나타내는 염.Formula (I):

Wherein R ¹ and R ² independently of one another represent a fluorine atom or a C ₁ -C ₆ perfluoroalkyl group. X ¹ represents a divalent C _{1 -} C ₁₇ saturated hydrocarbon group, the hydrogen atom contained in the bivalent saturated hydrocarbon group may be substituted with a fluorine atom, and -CH ₂ - contained in the bivalent saturated hydrocarbon group may be replaced by -O- Or -CO-. And Z < ^{1 +} > represents an organic counter ion.

Description

[0001] SALT AND PHOTORESIST COMPOSITION [0002]

The present invention relates to a salt and a photoresist composition containing the same.

The photoresist composition used in the microfabrication of semiconductors using lithography technology contains salts for acid generators.

Japanese Patent Application Laid-Open No. 2007-161707 discloses triphenylsulfonium (2-adamantyloxycarbonyl) difluoromethanesulfonate as a salt for an acid generator.

According to the present invention,

[1] Formula (I):

Wherein R ¹ and R ² independently of one another represent a fluorine atom or a C ₁ -C ₆ perfluoroalkyl group. X ¹ represents a divalent C _{1 -} C ₁₇ saturated hydrocarbon group, the hydrogen atom contained in the bivalent saturated hydrocarbon group may be substituted with a fluorine atom, and -CH ₂ - contained in the bivalent saturated hydrocarbon group may be replaced by -O- Or -CO-. And Z < ^{1 +} > represents an organic counter ion.

[2] X ¹ is * -CO-O-CH ₂ -CO- or _{-CH 2 -O-CO-CH 2} - (* is ^{-C (R 1) (R 2} ) - represents a binding site with) the A salt according to [1];

[3] The salt according to [1] or [2], wherein Z ^{1 +} is arylsulfonium cation.

[4] An acid generator containing a salt according to any one of [1] to [3];

[5] A photoresist composition containing an acid generator and a resin according to [4];

[6] The photoresist composition according to [5], further comprising an acid generator different from the salt represented by the formula (I);

[7] The acid generator which is different from the salt represented by the formula (I), the compound represented by the formula (B1):

Wherein Q ¹ and Q ² each independently represent a fluorine atom or a C ₁ -C ₆ perfluoroalkyl group. L ^b1 represents a single bond or a divalent C ₁ -C ₁₇ saturated hydrocarbon group, and -CH ₂ - contained in the divalent saturated hydrocarbon group may be substituted with -O- or -CO-. Y represents a C ₁ -C ₁₈ aliphatic hydrocarbon group which may have a substituent or a C ₃ -C ₁₈ saturated cyclic hydrocarbon group which may have a substituent, and the -CH ₂ - group contained in the aliphatic hydrocarbon group and the saturated cyclic hydrocarbon group, May be substituted with -O-, -SO ₂ - or -CO-. And Z ^& lt ^{; +} > represents an organic cation; [6] a photoresist composition according to [6];

[8] L ^b1 (*) Represents -CO-O- (* represents a bonding site with -C (Q ¹ ) (Q ² ) -);

[9] A photoresist composition according to [7] or [8], wherein Z ⁺ is triarylsulfonium cation.

[10] The photoresist as described in any one of [5] to [9], wherein the resin has an acid-labile group and is insoluble or hardly soluble in an aqueous alkali solution and can be dissolved in an alkali aqueous solution by the action of an acid. Composition;

[11] The photoresist composition described in any one of [5] to [10], further comprising a basic compound;

[11] (1) A process for producing a photoresist composition, comprising the steps of: applying the photoresist composition described in any one of [5] to [11]

(2) a step of drying the formed photoresist composition layer to form a photoresist film,

(3) a step of exposing the photoresist film,

(4) a step of heating the photoresist film after exposure, and

(5) a step of developing the photoresist film after heating; And the like.

The salt of the present invention can be used as an acid generator for a photoresist composition, and a photoresist pattern having excellent line edge roughness (LER) can be obtained by using a photoresist composition containing the salt.

The salt of the present invention is a salt of the formula (I):

Wherein R ¹ and R ² independently of one another represent a fluorine atom or a C ₁ -C ₆ perfluoroalkyl group. X ¹ represents a divalent C _{1 -} C ₁₇ saturated hydrocarbon group, the hydrogen atom contained in the bivalent saturated hydrocarbon group may be substituted with a fluorine atom, and -CH ₂ - contained in the bivalent saturated hydrocarbon group may be replaced by -O- Or -CO-. Z < ^{1 +} > represents an organic counter ion)

And can be used as an acid generator for a photoresist composition.

Examples of the C ₁ -C ₆ perfluoroalkyl group include a perfluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluoro-sec-butyl group, A perfluoro-tert-butyl group, a perfluoropentyl group, and a perfluorohexyl group.

R ¹ And R ² are each independently preferably a perfluoromethyl group or a fluorine atom, and R ¹ and R ² Is more preferably a fluorine atom.

Examples of the divalent C ₁ -C ₁₇ saturated hydrocarbon group include a linear alkylene group, a branched alkylene group, a monocyclic or polycyclic saturated cyclic hydrocarbon group, and a group formed by combining two or more of these groups. Specific examples include methylene, ethylene, propane-1,3-diyl, propane-1,2-diyl, butane-1,4-diyl, pentane- Diyl group, a heptane-1,7-diyl group, an octane-1,8-diyl group, a nonane-1,9-diyl group, A dodecane-1,12-diyl group, a tridecane-1,13-diyl group, a tetradecane-1,14-diyl group, a pentadecane-1,15-diyl group, a hexadecane-1,16- , Heptadecane-1,17-diyl group and the like; Methylpropane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, Branched alkylene groups such as a methylbutane-1,4-diyl group; Monocyclic saturated cyclic hydrocarbon groups such as a 1,3-cyclobutylene group, a 1,3-cyclopentylene group, a 1,4-cyclohexylene group and a 1,5-cyclooctylene group; And polycyclic saturated cyclic hydrocarbon groups such as a 1,4-norbornylene group, a 2,5-norbornylene group, a 1,5-adamantylene group and a 2,6-adamantylene group. Further, from the monovalent saturated cyclic hydrocarbon group described below, bivalent saturated cyclic hydrocarbon groups having one arbitrary hydrogen atom as a bonding number (bonding hand) can be used.

One or more -CH ₂ - contained in such a divalent C ₁ -C ₁₇ saturated hydrocarbon group may be substituted with -O- or CO-. In addition, the optionally substituted divalent C ₁ ~C ₁₇ saturated hydrocarbon group, a fluorine atom.

X ¹ is a group represented by the formula (X1):

Wherein mx represents an integer of 0 or 1; X ¹¹ represents a C ₁ to C ₁₄ saturated hydrocarbon group. * Represents a bonding site with -C (R ¹ ) (R ² ) -]

.

The group represented by the formula (X1) includes a group represented by the formula (X-1) and a group represented by the formula (X1-2), more preferably a group represented by the formula (X1-2).

Wherein X ¹¹ represents a C ₁ to C ₁₄ saturated hydrocarbon group. * Represents a bonding site with -C (R ¹ ) (R ² ) -]

X ¹¹ is preferably -CH ₂ -, - (CH ₂ ) ₂ -, - (CH ₂ ) ₄ -, - (CH ₂ ) ₈ - or - (CH ₂ ) ₁₂ -.

Examples of the divalent group represented by the formula (X1-2) include the groups shown below.

[Wherein * represents a bonding site with -C (R ¹ ) (R ² ) -]

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

Examples of Z ¹⁺ include onium cationes such as sulfonium cation, iodonium cation, ammonium cation, benzothiazolium cation, and phosphonium cation, and sulfonium cation and iodonium cation are preferable More preferred is aryl sulfonium cation, and triaryl sulfonium cation is particularly preferred.

Z ^{1 +} is preferably a cation represented by the formula (b2-1), the formula (b2-2), the formula (b2-3) or the formula (b2-4).

In formula (b2-1), R ^b4 to R ^b6 independently represent a C ₁ to C ₃₀ aliphatic hydrocarbon group, a C _{3 to} C ₃₆ saturated cyclic hydrocarbon group, or a C _{6 to} C ₁₈ aromatic hydrocarbon group. The aliphatic hydrocarbon group may be substituted with a hydroxyl group, a C _{1 to} C ₁₂ alkoxy group or a C _{6 to} C ₁₈ aromatic hydrocarbon group, and the saturated cyclic hydrocarbon group may be substituted with a halogen atom, a C _{2 to} C ₄ acyl group or a glycidyloxy And the aromatic hydrocarbon group may be substituted with a halogen atom, a hydroxyl group, a C _{1 to} C ₃₆ aliphatic hydrocarbon group, a C _{3 to} C ₃₆ saturated cyclic hydrocarbon group or a C _{1 to} C ₁₂ alkoxy group.

In formula (b2-2), R ^b7 and R ^b8 each independently represent a hydroxyl group, a C ₁ -C ₁₂ An aliphatic hydrocarbon group or a C _{1 to} C ₁₂ alkoxy group. m2 and n2 each independently represent an integer of 0 to 5;

In formula (b2-3), R ^b9 and R ^b10 each independently represent a C ₁ to C ₃₆ aliphatic hydrocarbon group or a C _{3 to} C ₃₆ saturated cyclic hydrocarbon group.

R ^b11 represents a hydrogen atom, a C _{1 to} C ₃₆ aliphatic hydrocarbon group, a C _{3 to} C ₃₆ saturated cyclic hydrocarbon group, or a C _{6 to} C ₁₈ aromatic hydrocarbon group.

The aliphatic hydrocarbon group of R ^b9 to R ^b11 is preferably a C ₁ to C ₁₂ aliphatic hydrocarbon group, and the saturated cyclic hydrocarbon group is preferably a C ₄ to C ₁₂ saturated cyclic hydrocarbon group.

R ^b12 is C ₁ -C ₁₂ Aliphatic hydrocarbon groups, C ₃ ~C ₁₈ A saturated cyclic hydrocarbon group or a C _{6 to} C ₁₈ aromatic hydrocarbon group. The aromatic hydrocarbon group is preferably a C ₁ -C ₁₂ An aliphatic hydrocarbon group, a C _{1 to} C ₁₂ alkoxy group, a C _{3 to} C ₁₈ saturated cyclic hydrocarbon group, or an alkylcarbonyloxy group. R ^b9 And R ^b10 and R ^b11 And R ^b12 each independently may combine with each other to form a 3-membered to 12-membered ring, preferably a 3-membered to 7-membered ring, and at least one -CH ₂ - contained in these rings may be - O-, -S-, or -CO-.

In the formula (b2-4), R ^b13 to R ^b18 Are, each independently, a hydroxyl group, C ₁ ~C ₁₂ An aliphatic hydrocarbon group or a C _{1 to} C ₁₂ alkoxy group.

L ^b11 Represents -S- or O-. o2, p2, s2 and t2 each independently represent an integer of 0 to 5, q2 and r2 each independently represent an integer of 0 to 4, and u2 represents 0 or 1.

Examples of the aliphatic hydrocarbon group include a methyl group, an ethyl group, a propyl group, a 1-methylethyl group (isopropyl group), a butyl group, a 1,1-dimethylethyl group (tert- butyl group), a 2,2- , 2-methylpropyl group, 1,2-dimethylpropyl group, 2,2-dimethylpropyl group, 1-ethylpropyl group, pentyl group, 1-methylbutyl group, A pentyl group, a 1-methylpentyl group, a 1,4-dimethylhexyl group, a heptyl group, a 1-methylheptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, etc. Alkyl group.

The saturated cyclic hydrocarbon group may be monocyclic or polycyclic. Specific examples thereof include monocyclic saturated cyclic hydrocarbon groups such as cycloalkyl groups (e.g., cyclopentyl, cyclohexyl, methylcyclohexyl, dimethylcyclohexyl, cycloheptyl and cyclooctyl groups); A group obtained by hydrogenating a condensed aromatic hydrocarbon group (e.g., a hydro naphthyl group and the like); And polycyclic saturated cyclic hydrocarbon groups such as a cyclic cyclic hydrocarbon group (for example, adamantyl group, norbornyl group, methylnorbornyl group and the like). Also, a group condensed with a cross-linking ring (for example, a norbornane ring and the like) and a ring (for example, a cycloheptane ring, a cyclohexane ring, etc.) or a ring (for example, a decahydronaphthalene ring) Or a group in which the bridging rings are condensed; And a group in which these are combined (methylcyclohexyl, dimethylcyclohexyl, methylnorbornyl etc.).

Examples of the aromatic hydrocarbon group include a phenyl group, a naphthyl group, an anthryl group, a p-methylphenyl group, a p-tert-butylphenyl group, a p- , Phenanthryl group, 2,6-diethylphenyl group, and 2-methyl-6-ethylphenyl group.

Examples of the alkoxy group include a methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxy group, sec-butoxy group, tert-butoxy group, pentyloxy group, hexyloxy group, heptyloxy group, Ethylhexyloxy group, nonyloxy group, decyloxy group, undecyloxy group, dodecyloxy group and the like.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

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, a propylcarbonyloxy group, an isopropylcarbonyloxy group, a butylcarbonyloxy group, a sec-butylcarbonyloxy group, a tert- A pentylcarbonyloxy group, a hexylcarbonyloxy group, an octylcarbonyloxy group, and a 2-ethylhexylcarbonyloxy group.

^Examples of the ring formed by R ^b9 and R ^b10 include a thioran-1-ium ring (tetrahydrothiophenium ring), a thian-1-ium ring and a 1,4-oxathian- have.

Examples of the ring formed by R ^b11 and R ^b12 include oxocycloheptane ring, oxocyclohexane ring, oxonorbornane ring, oxoamantane ring and the like.

In the formulas (b2-1) to (b2-4), preferred aliphatic hydrocarbon groups are aliphatic hydrocarbon groups such as methyl, ethyl, propyl, isopropyl, butyl, sec- , An octyl group, and a 2-ethylhexyl group.

Preferred saturated cyclic hydrocarbon groups are cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclodecyl, 2-alkyl-2-adamantyl, 1- (1- adamantyl) -1-alkyl group and an isobornyl group.

Preferred aromatic hydrocarbon groups are phenyl, 4-methylphenyl, 4-ethylphenyl, 4-tert-butylphenyl, 4-cyclohexylphenyl, 4-methoxyphenyl, biphenyl and naphthyl.

Examples of the aliphatic hydrocarbon group (aralkyl group) in which the substituent is an aromatic hydrocarbon group include a benzyl group and the like.

Among them, the cation represented by the formula (b2-1) is preferable, and the cation represented by the formula (b2-1-1) is more preferable.

( ^Wherein R ^b19 to R ^b21 each independently represent a halogen atom, a hydroxyl group, a C _{1 to} C ₃₆ aliphatic hydrocarbon group, a C _{3 to} C ₃₆ saturated cyclic hydrocarbon group, or a C _{1 to} C ₁₂ alkoxy group. The hydrocarbon group may be substituted by a hydroxyl group, a C _{1 to} C ₁₂ alkoxy group, or a C _{6 to} C ₁₈ aromatic hydrocarbon group, and the saturated cyclic hydrocarbon group may be substituted with a halogen atom, a C _{2 to} C ₄ acyl group or a glycidyloxy V2, w2 and x2 each independently represents an integer of 0 to 5)

The aliphatic hydrocarbon group is preferably C ₁ -C ₁₂ An aliphatic hydrocarbon group, and a saturated cyclic hydrocarbon group is preferably a C ₄ to C ₃₆ saturated cyclic hydrocarbon group.

v2, w2 and x2 preferably represent 0 or 1.

In the formula (b2-1-1), R ^b19 to R ^b21 each preferably independently represent a halogen atom (more preferably a fluorine atom), a hydroxyl group, a C _{1 to} C ₁₂ alkyl group or a C _{1 to} C ₁₂ alkoxy And v2, w2 and x2 each independently represent an integer of 0 to 5 (preferably 0 or 1).

Particularly, triphenylsulfonium cation (in the formula (b2-1-1), v2, w2 and x2 are preferably 0).

As the cation represented by the formula (b2-1), the following cation can be given.

Examples of the cation represented by the formula (b2-2) include the following cation.

Examples of the cation represented by the formula (b2-3) include the following cation.

Examples of the cation represented by the formula (b2-4) include the following cation.

The salt represented by the formula (I) is an arbitrary combination of the anion described above and the organic cation. Among them, the salts shown below are preferable.

The salt represented by the formula (I) can be produced, for example, by the following method. In the following reaction formulas, unless otherwise stated, the definition of each substituent has the same meaning as described above.

X ¹ The salt represented by the formula (IA) wherein the group (-CO-) represented by the formula (X1-1) is prepared by reacting the salt represented by the formula (IA-1) and the compound represented by the formula (IA- In the presence of a catalyst such as carbonyldiimidazole in a solvent such as tetrahydrofuran or the like. The salt represented by the formula (IA-1) can be synthesized by the method described in JP-A-2008-127367. The compound represented by the formula (IA-2) is commercially available as 2,10-camphorsulfame.

The salt represented by the formula (IB) wherein X ¹ is a group (-CO-OX ¹¹ -CO-) represented by the formula (X1-2) can be obtained by reacting a salt represented by the formula (IB- In the presence of a catalyst such as potassium iodide, potassium carbonate or the like in a solvent such as N, N-dimethylformamide. The salt represented by the formula (IB-1) can be synthesized by the method described in JP-A-2008-127367.

The salt represented by the formula (IB-2) can be prepared by reacting a compound represented by the formula (IB-3) and a compound represented by the formula (IB-4) in the presence of a base catalyst such as sodium hydride in a solvent such as toluene . Examples of the compound represented by the formula (IB-4) include chloroacetyl chloride and the like.

The acid generator of the present invention contains a salt represented by the formula (I). The acid generator of the present invention may contain two or more kinds of salts represented by formula (I).

The acid generator of the present invention may be composed solely of the salt represented by the formula (I), or may contain an acid generator different from the salt represented by the formula (I), in addition to the salt represented by the formula (I).

In the photoresist composition of the present invention, the content of the salt represented by the formula (I) is preferably 0.1 parts by weight or more, more preferably 0.5 parts by weight, more preferably 1 part by weight Or more. In the photoresist composition of the present invention, the content of the salt represented by the formula (I) is preferably 30 parts by weight or less, more preferably 20 parts by weight or less, relative to 100 parts by weight of the resin, Is not more than 10 parts by weight.

The acid generator other than the salt represented by the formula (I) may be a nonionic acid generator or an ionic acid generator. Examples of the nonionic acid generators include organic halides, sulfonate esters (e.g., 2-nitrobenzyl ester, aromatic sulfonate, oxime sulfonate, N-sulfonyloxyimide, N-sulfonyloxyimide, Sulfonylurea, sulfonyloxyketone, DNQ 4-sulfonate), sulfones (for example, disulfone, ketosulfone, sulfonyldiazomethane). Examples of the ionic acid generator include onium salts containing onium cation (for example, diazonium salts, phosphonium salts, sulfonium salts, iodonium salts). Examples of the anion of the onium salt include a sulfonic anion, a sulfonylimide anion, and a sulfonylated anion.

Examples of the acid generator other than the salt represented by the formula (I) include an acid generator (particularly a photo acid generator) used in the photoresist field, a photoinitiator for photo cationic polymerization, a photo- A known compound which generates an acid by irradiation with light (light) such as an antioxidant or the like and a mixture thereof can be suitably used. For example, JP-A-63-26653, JP-A-55-164824, JP-A-62-69263, JP-A-63-146038, JP-A- The radiation disclosed in Japanese Patent Application Laid-Open No. 163452, Japanese Patent Laid-Open Nos. 62-153853, 63-146029, US Patent No. 3,779,778, US Patent No. 3,849,137, German Patent No. 3914407, European Patent No. 126,712 A compound capable of generating an acid may be used.

The acid generator other than the salt represented by the formula (I) is preferably a fluorine-containing acid generator, more preferably a compound represented by the formula (B1):

Wherein Q ¹ and Q ² each independently represent a fluorine atom or a C ₁ -C ₆ perfluoroalkyl group. L ^b1 represents a single bond or a divalent C ₁ -C ₁₇ saturated hydrocarbon group, and -CH ₂ - contained in the bivalent saturated hydrocarbon group may be substituted with -O- or -CO-. Y represents a C ₁ -C ₁₈ aliphatic hydrocarbon group which may have a substituent or a C ₃ -C ₁₈ saturated cyclic hydrocarbon group which may have a substituent, and the -CH ₂ - group contained in the aliphatic hydrocarbon group and the saturated cyclic hydrocarbon group, May be substituted with -O-, -SO ₂ - or -CO-. Z ^& lt ^{; +} > represents an organic cation.

Lt; / RTI >

Examples of the C ₁ -C ₆ perfluoroalkyl group include the same ones as described above, and Q ¹ and Q ² are each independently preferably a perfluoromethyl group or a fluorine atom, and more preferably a fluorine atom .

Examples of the substituent which may be substituted for the aliphatic hydrocarbon group or the saturated cyclic hydrocarbon group in Y include a halogen atom (except for a fluorine atom), a hydroxyl group, an oxo group (= O), a C _{1 to} C ₁₂ aliphatic hydrocarbon group, hydroxyl group-containing C ₁ ~C ₁₂ aliphatic hydrocarbon groups, C ₃ ~C ₁₆ saturated cyclic hydrocarbon group, C ₁ ~C ₁₂ alkoxy group, C ₆ ~C ₁₈ aromatic hydrocarbon group, C ₇ ~C ₂₁ aralkyl group, C ₂ ~ C ₄ acyl group, a glycidyloxy group and a - (CH ₂₎ a group (represented by the formula ^{_{j2 -O-CO-R b1,}} R b1 is a C ₁ ~C ₁₆ aliphatic hydrocarbon groups, C ₃ ~C ₁₆ A saturated cyclic hydrocarbon group or a C ₆ -C ₁₈ An aromatic hydrocarbon group. and j2 represents an integer of 0 to 4).

Examples of the hydroxyl group-containing aliphatic hydrocarbon group include a hydroxymethyl group and a hydroxyethyl group.

The aliphatic hydrocarbon group, saturated cyclic hydrocarbon group, aromatic hydrocarbon group and aralkyl group which are substituents of Y may further have a substituent. Examples of the substituent include a C ₁ -C ₆ alkyl group, a halogen atom, a hydroxyl group, and an oxo group.

The group in which -CH ₂ - is replaced by -O- or -CO- in the aliphatic hydrocarbon group or saturated cyclic hydrocarbon group represented by Y is an ether bond or a cyclic ether bond (group in which -CH ₂ - is substituted with -O- A saturated cyclic hydrocarbon group having an oxo group (a group in which -CH ₂ - is substituted with -CO-), a sultone ring group (two adjacent -CH ₂ - are each -O- or -SO ₂ -) and a lactone ring group (the group in which two adjacent -CH ₂ - are substituted with -O- or -CO-), and the like.

Examples of the saturated cyclic hydrocarbon group in this group include groups represented by formulas (Y1) to (Y26).

The saturated cyclic hydrocarbon group is preferably a group represented by any one of formulas (Y1) to (Y19), more preferably a group represented by formula (Y11), formula (Y14), formula (Y15) More preferably a group represented by formula (Y11) or formula (Y14).

Examples of Y which is a saturated cyclic hydrocarbon group substituted with an aliphatic hydrocarbon group include the following groups.

A saturated cyclic hydrocarbon group substituted with a hydroxyl group or a hydroxyl group-containing aliphatic hydrocarbon group, Y Include the following groups.

A saturated cyclic hydrocarbon group substituted with an aromatic hydrocarbon group, Y Include the following groups.

As Y which is a saturated cyclic hydrocarbon group substituted with a group represented by - (CH ₂ ) _{j 2} -O-CO-R ^b1 , the following groups may be mentioned.

Y is preferably an adamantyl group which may have a substituent (for example, an oxo group or the like), more preferably an adamantyl group or an oxo-adamantyl group.

Examples of the group in which -CH ₂ - contained in the saturated hydrocarbon group of L ^b1 are substituted with -O- or -CO- include groups represented by formulas (b1-1) to (b1-6). Is preferably a group represented by the formula (b1-1), (b1-2), (b1-3) or (b1-4), more preferably a group represented by the formula (b1-1) 2). In the formula (b1-1) ~ formula (b1-6), * is ^{-C (Q 1) (Q 2} ) - refers to the binding sites for.

( ^Wherein L ^b2 , L ^b3 , L ^b4 , L ^b5 , L ^b6 , L ^b7 , L ^b8 , L ^b9 and L ^b10 have the same meanings as defined above)

Among them, a group represented by formula (b1-1) is preferable, and a group represented by formula (b1-1) in which L ^b2 is a single bond or -CH ₂ - is more preferable.

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

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

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

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

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

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

The anion in the formula (B1) is preferably an anion in which L ^b1 is a group represented by the formula (b1-1), and an anion represented by the formula (b1-1-1) to (b1-1-9) Temperature is more preferable.

Formula (b1-1-1) ~ wherein, Q ^1, Q ² and L ^b2 (b1-1-9) Are the same as above. R ^b2 and R ^b3 Each independently represent a C ₁ to C ₄ aliphatic hydrocarbon group (preferably a methyl group)

Specific examples of anion in the formula (B1) include the following.

Among them, Hanyan is preferable.

The cation Z ⁺ contained in the salt represented by the formula (B1) is the same as the canon Z ^{1 + of the} salt represented by the formula (I).

The salt represented by the formula (B1) is a combination of any of the above-mentioned anions and organic cations. The anion and cation described above can be arbitrarily combined, but any of the anions represented by the formulas (b1-1-1) to (b1-1-9) and the cation represented by the formula (b2-1-1) , And a combination of any of the anions represented by the formulas (b1-1-3) to (b1-1-5) and the cation represented by the formula (b2-3) is preferable.

The salt represented by the preferable formula (B1) is a salt represented by the formula (B1-1) to (B1-17). Among them, the compounds represented by the formulas (B1-1), (B1-2), (B1-6), (B1-11), (B1-12), (B1-13) and -14) is more preferable.

When the photoresist composition of the present invention contains a salt represented by the formula (B1), its content is preferably at least 1 part by mass, more preferably at least 3 parts by mass, relative to 100 parts by mass of the resin, Is preferably 30 parts by mass or less, more preferably 25 parts by mass or less, based on 100 parts by mass of the resin.

The photoresist composition of the present invention contains an acid generator containing a salt represented by the formula (I) and a resin (hereinafter sometimes referred to as "resin (A)"). The resin (A) herein is a resin which has an acid-labile group and is insoluble or sparingly soluble in an aqueous alkali solution, and which can be dissolved in an aqueous alkaline solution under the action of an acid.

In the photoresist composition of the present invention, an acid is generated from the salt represented by the formula (I) by exposure. The acid catalytically acts on the acid-unstable group in the resin to cleave the acid-unstable group to make the resin soluble in the aqueous alkaline solution.

≪ Resin (A) >

Resin (A) is a resin which becomes alkali-soluble by the action of an acid. The resin that becomes alkali-soluble by the action of an acid can be produced by polymerizing a monomer having an acid-unstable group (hereinafter may be referred to as " monomer having an acid-unstable group ") in some cases. do. By " alkali becomes soluble by the action of an acid " it is meant that it is insoluble or sparing in an aqueous alkali solution before contact with acid, but becomes soluble in an aqueous alkali solution after contact with acid. The monomers having an acid labile group may be used singly or in combination of two or more.

≪ Monomer having an acid labile group >

The term " acid labile group " means a group which is cleaved on contact with an acid to form a hydrophilic group (for example, a hydroxyl group or a carboxyl group (-COOH)). Examples of the group unstable to the acid include a group represented by the formula (1). Hereinafter, the group represented by the formula (1) may be referred to as "acid-unstable group (1)".

(Wherein R ^a1 to R ^a3 Each independently represent an aliphatic hydrocarbon group or a saturated cyclic hydrocarbon group, and R ^a2 and R ^a3 May be coupled to each other. * Represents a binding site)

When R ^a2 and R ^a3 are bonded to each other, a ring to be formed together with the bonding carbon is formed. Examples of the ring include an alicyclic hydrocarbon group and an aromatic hydrocarbon group. C _{3 to} C ₂₀ rings are preferable, and C _{3 to} C ₁₂ rings are more preferable.

The alicyclic hydrocarbon group may be either monocyclic or polycyclic. Examples of monocyclic saturated cyclic hydrocarbon groups include cycloalkyl groups (e.g., cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl groups) and cycloalkenyl groups (e.g., cyclopentenyl, Heptenyl group, cyclooctenyl group), and the like. Examples of the polycyclic saturated hydrocarbon group include groups obtained by hydrogenating a condensed aromatic hydrocarbon group (e.g., a hydro naphthyl group), a crosslinked cyclic hydrocarbon group (e.g., an adamantyl group and a norbornyl group), and the like. A group in which a cross-linked ring (for example, a norbornane ring) and a ring (for example, a cycloheptane ring or a cyclohexane ring) or a ring (for example, a decahydronaphthalene ring) Is included in a saturated or unsaturated cyclic hydrocarbon group in which the bridged rings are condensed with each other.

In the formula (1), R ^a1 to R ^a3 , The hydrogen atom of the aliphatic hydrocarbon group and the saturated cyclic hydrocarbon group may be substituted with a hydroxyl group or the like. The -CH ₂ - of the aliphatic hydrocarbon group and the saturated cyclic hydrocarbon group may be substituted with -O- or CO-.

R ^a1 to R ^a3 are preferably a C ₁ to C ₂₀ group, more preferably a C ₁ to C ₁₂ group.

Examples of the acid labile group (1) include 1,1-dialkylalkoxycarbonyl groups (in the formula (1), R ^a1 to R ^a3 are alkyl groups, preferably tert-butoxycarbonyl groups) Adamantyloxycarbonyl group (in the formula (1), R ^a1 and R ^a2 and a carbon atom form an adamantyl group and R ^a3 is an alkyl group) and 1- (1-adamantyl) -1-alkylalkoxycarbonyl group (In the formula (1), R ^a1 and R ^a2 are alkyl groups and R ^a3 is an adamantyl group).

The monomer having an acid labile group is preferably a (meth) acrylic acid-based monomer having an acid-unstable group (1) and a monomer having a carbon-carbon double bond, more preferably an acid-unstable group (1).

As used herein, "(meth) acrylic acid" means acrylic acid and / or methacrylic acid, and "(meth) acrylate" means acrylate and / or methacrylate.

Among the (meth) acrylic acid monomers having an acid-unstable group (1), those having a saturated cyclic hydrocarbon group of 5 to 20 carbon atoms are preferred. When a resin obtained by polymerizing a monomer having a bulky structure such as a saturated cyclic hydrocarbon group is used, the resolution of the photoresist can be improved. In particular, a monomer having an acid labile group represented by the formula (a1-1) or (a1-2) is preferable. These may be used alone or in combination of two or more.

In formula (a1-1) and formula (a1-2), L ^a1 and L ^a2 each independently represent * -O- or * -O- (CH ₂ ) _k1 -CO-O-, Represents an integer of 1 to 7. * Represents a bonding site with -CO-. R ^a4 and R ^a5 each independently represent a hydrogen atom or a methyl group. R ^a6 and R ^a7 each independently represent a C ₁ to C ₈ aliphatic hydrocarbon group or a C _{3 to} C ₁₀ saturated cyclic hydrocarbon group; m1 represents an integer of 0 to 14; and n1 represents an integer of 0 to 10 .

L ^a1 and L ^a2 are preferably * -O- or * -O- (CH ₂ ) _f1 -CO-O- (f1 is an integer of 1 to 4), more preferably * -O- .

R ^a4 and R ^a5 are preferably methyl groups. The carbon number of the aliphatic hydrocarbon group of R ^a6 and R ^a7 is preferably 6 or less, and the carbon number of the saturated cyclic hydrocarbon group is preferably 8 or less, more preferably 6 or less. ^Examples of the aliphatic hydrocarbon group for R ^a6 and R ^a7 include a methyl group, an ethyl group, a 1-methylethyl group (isopropyl group), a 1,1-dimethylethyl group (tert-butyl group), a 2,2- Methylpropyl group, 1-propylbutyl group, pentyl group, 1-methylpropyl group, 2-methylpropyl group, Methylpentyl group, hexyl group, 1,4-dimethylhexyl group, heptyl group, 1-methylheptyl group and octyl group. ^Examples of the saturated cyclic hydrocarbon group of R ^a6 and R ^a7 include a cycloheptyl group, a methylcycloheptyl group, a cyclohexyl group, a methylcyclohexyl group, a dimethylcyclohexyl group, a norbornyl group and a methylnorbornyl group.

m1 is preferably an integer of 0 to 3, more preferably 0 or 1. n1 is preferably an integer of 0 to 3, more preferably 0 or 1. k1 is preferably an integer of 1 to 4, more preferably 1.

Examples of the monomer represented by the formula (a1-1) include the followings.

Among them, 2-methyl-2-adamantyl (meth) acrylate, 2-ethyl-2-adamantyl (meth) acrylate and 2-isopropyl-2-adamantyl Adamantyl methacrylate, 2-methyl-2-adamantyl methacrylate, 2-ethyl-2-adamantyl methacrylate and 2-isopropyl-2-adamantyl methacrylate methacrylate are more preferable.

The monomer represented by the formula (a1-2) includes, for example, the following.

Among them, 1-ethyl-1-cyclohexyl (meth) acrylate is preferable, and 1-ethyl-1-cyclohexyl methacrylate is more preferable.

The content of the structural unit derived from the monomer represented by the formula (a1-1) or the formula (a1-2) in the resin is generally from 10 to 95 mol%, preferably from 15 to 90 mol% Mol%, and more preferably 20 to 85 mol%.

Examples of the monomer having an acid labile group and a carbon-carbon double bond include a monomer represented by the formula (a1-3). Resins having a structural unit derived from a monomer (a1-3) having an acid-labile group have a bulky structure, so that the resolution of the photoresist can be improved. Further, the monomer (a1-3) having an acid labile group can improve the dry etching resistance of the photoresist by introducing a norbornane ring rigid in the main chain of the resin.

(In the formula, R ^a9 is C ₁ ~C ₃ which may have a hydrogen atom, an optionally substituted (e.g., hydroxy) An aliphatic hydrocarbon group, a carboxyl group, a cyano group or -COOR ^a13 It represents a, R ^a13 is a C ₁ ~C ₈ An aliphatic hydrocarbon group or a C ₃ -C ₈ And the hydrogen atoms of the aliphatic hydrocarbon group and the saturated cyclic hydrocarbon group may be substituted with a hydroxyl group, and the -CH ₂ - of the aliphatic hydrocarbon group and the saturated cyclic hydrocarbon group may be replaced by -O- or -O- or a saturated cyclic hydrocarbon group, CO-. ≪ / RTI > R ^a10 to R ^a12 each independently represent a C ₁ to C ₁₂ An aliphatic hydrocarbon group or a C _{3 to} C ₁₂ A saturated cyclic hydrocarbon group, or R ^a10 and R ^a11 may be bonded to each other to form a ring. The hydrogen atoms of the aliphatic hydrocarbon group and the saturated cyclic hydrocarbon group may be substituted with a hydroxyl group or the like, and -CH ₂ - of the aliphatic hydrocarbon group and the saturated cyclic hydrocarbon group may be substituted with -O- or CO- do.

^Examples of the aliphatic hydrocarbon group which may have a substituent represented by R ^a9 include a methyl group, an ethyl group, a propyl group, a hydroxymethyl group and a 2-hydroxyethyl group.

^Examples of R ^a13 include a methyl group, an ethyl group, a propyl group, a 2-oxo-oxolan-3-yl group and a 2-oxo-oxolan-4-yl group.

^{Examples of} R ^a10 to R ^a12 include a methyl group, an ethyl group, a cyclohexyl group, a methylcyclohexyl group, a hydroxycyclohexyl group, an oxocyclohexyl group and an adamantyl group. ^{Examples of} the saturated cyclic hydrocarbon group formed by R ^a10 and R ^a11 and the carbon to which they are bonded include a cyclohexyl group and an adamantyl group.

Examples of the monomer represented by the formula (a1-3) include tert-butyl 5-norbornene-2-carboxylate, 1-cyclohexyl-1-methylethyl 5-norbornene- Norbornene-2-carboxylic acid 1-methylcyclohexyl, 5-norbornene-2-carboxylic acid 2-methyl-2-adamantyl, 5-norbornene- Norbornene-2-carboxylic acid 1- (4-methylcyclohexyl) -1-methylethyl, 5-norbornene-2-carboxylic acid 1- 1-methyl-1- (4-oxocyclohexyl) ethyl and 5-norbornene-2-carboxylic acid 1- 1-adamantyl) -1-methylethyl.

The content of the structural unit derived from the monomer represented by the formula (a1-3) in the resin is generally 10 to 95 mol%, preferably 15 to 90 mol% in the total structural units of the resin, Is 20 to 85 mol%.

Examples of the monomer having an acid labile group and a carbon-carbon double bond include a monomer represented by the formula (a1-4).

In formula (a1-4)

R ¹⁰ is a hydrogen atom, a halogen atom or a C ₁ -C ₆ Alkyl group.

R ¹¹ each independently represents a halogen atom, a hydroxyl group, a C ₁ -C ₆ Alkyl group, C ₁ ~C ₆ Alkoxy group, C ₂ ~C ₄ acyl, C ₂ ~C ₄ acyloxy, denotes an acryloyl group or a methacryloyl.

and la represents an integer of 0 to 4. When la is an integer of 2 or more, a plurality of R < ¹¹ > may be the same kind of group or different groups.

R ¹² and R ¹³ each independently represent a hydrogen atom or a C _{1 to} C ₁₂ hydrocarbon group.

X ^a2 represents a divalent C ₁ -C ₁₇ saturated hydrocarbon group which may have a single bond or a substituent, and -CH ₂ - contained in the saturated hydrocarbon group may be replaced by -CO-, -O-, -S-, -SO ₂ - Or N (R < ^c >) -. R ^c Is a hydrogen atom or a C ₁ ~C ₆ Alkyl group.

Y ^a3 is C ₁ ~C ₁₂ Aliphatic hydrocarbon groups, C ₃ ~C ₁₈ A saturated cyclic hydrocarbon group or a C _{6 to} C ₁₈ aromatic hydrocarbon group, and the aliphatic hydrocarbon group, saturated cyclic hydrocarbon group and aromatic hydrocarbon group may have a substituent.

Examples of the alkyl group which may have a halogen atom include a perfluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluoro sec-butyl group, a perfluoro a tert-butyl group, a perfluoropentyl group, and a perfluorohexyl group.

The alkyl group in R ¹⁰ and R ¹¹ is preferably a C ₁ -C ₄ alkyl group, more preferably a C ₁ -C ₂ alkyl group, and particularly preferably a methyl group.

Alkoxy group in R ^11, C ₁ ~C ₄ alkoxy groups are preferable, C ₁ ~C ₂ alkoxy groups are more preferred, and a methoxy group is particularly preferred.

Examples of the acyloxy group include an acetyloxy group, a propionyloxy group and a butyryloxy group.

Examples of the hydrocarbon group include the same ones exemplified for the aliphatic hydrocarbon and the saturated cyclic hydrocarbon and combinations thereof (for example, 2-alkyl-2-adamantyl group, 1- (1-adamantyl) ) And the like.

The monomer represented by the formula (a1-4) includes, for example, the following monomers.

The content of the structural unit derived from the monomer represented by the formula (a1-4) in the resin (A) is generally 10 to 95 mol%, preferably 15 to 90 mol% in the total structural units of the resin, And more preferably 20 to 85 mol%.

The resin (A) is preferably a copolymer of a monomer having an acid labile group and a monomer having no acid labile group (hereinafter sometimes referred to as " acid stable monomer "). The acid stable monomers may be used singly or in combination of two or more kinds.

When the resin (A) is a copolymer of an acid-unstable group-containing monomer and an acid-stable monomer, the structural unit derived from a monomer having an acid-unstable group is preferably 10 to 80 mols %, More preferably 20 to 60 mol%.

It is also preferred that the monomer having an adamantyl group (in particular, the structural unit derived from the monomer (a1-1) having an acid labile group is at least 15 mol% based on 100 mol% of the monomer having an acid labile group. When the proportion of the monomer having an adamantyl group is increased, the dry etching resistance of the resist is improved.

The acid-stable monomer preferably has a hydroxyl group or a lactone ring. When a resin having a structural unit derived from an acid stable monomer containing a hydroxyl group-containing acid stable monomer or a lactone ring is used, the resolution of the photoresist and adhesion to the substrate can be improved.

≪ Acid-stable monomers having a hydroxyl group >

When the photoresist composition is used for exposure to high energy radiation such as KrF excimer laser exposure (248 nm), electron beam or EUV light, an acid stable monomer having a phenolic hydroxyl group such as hydroxystyrene is used as an acid stable monomer having a hydroxyl group . When ArF excimer laser exposure with a short wavelength (193 nm) or the like is used, it is preferable to use an acid stable monomer having a hydroxyadamantyl group represented by the formula (a2-1) as an acid stable monomer having a hydroxyl group. The acid-stable monomer having a hydroxyl group may be used singly or in combination of two or more kinds.

Examples of the monomer having a phenolic hydroxyl group include styrene monomers such as p- or m-hydroxystyrene represented by the formula (a2-0).

In the formula (a2-0)

R ⁸ represents a hydrogen atom, a halogen atom or a C ₁ -C ₆ Alkyl group, R ⁹ represents a halogen atom, a hydroxyl group, a C ₁ -C ₆ Alkyl group, C ₁ ~C ₆ Alkoxy group, C ₂ ~C ₄ acyl, C ₂ ~C ₄ acyloxy, denotes an acryloyl group or a methacryloyl, ma is an integer of zero to four. When ma is an integer of 2 or more, a plurality of R < ⁹ > may be groups of the same kind or may be groups of different kinds.

In the case of obtaining a copolymer resin having a structural unit derived from a monomer having a phenolic hydroxyl group, it is possible to obtain a copolymer resin by radical polymerization of a corresponding (meth) acrylic acid ester monomer, acetoxystyrene, and styrene, followed by deacetylation with an acid have.

Examples of the monomer having a phenolic hydroxyl group include the following monomers.

Of the above monomers, 4-hydroxystyrene or 4-hydroxy-? -Methylstyrene is particularly preferable.

The content of the structural unit derived from the monomer represented by the formula (a2-0) in the resin is generally from 5 to 90 mol%, preferably from 10 to 85 mol% in the total structural units of the resin, Is from 15 to 80 mol%.

As the acid stable monomer having a hydroxyadamantyl group, a monomer represented by the formula (a2-1) may be mentioned.

In formula (a2-1)

L ^a3 represents -O- or O- (CH ₂ ) _{k 2} -CO-O-, and _{k 2} represents an integer of 1 to 7. R ^a14 represents a hydrogen atom or a methyl group. R ^a15 and R ^a16 Each independently represent a hydrogen atom, a methyl group or a hydroxy group. o1 represents an integer of 0 to 10;

L ^a3 is preferably -O-, -O- (CH ₂ ) _f1 -CO-O- (f1 is an integer of 1 to 4), and more preferably -O-. R ^a14 is preferably a methyl group. R ^a15 is preferably a hydrogen atom. R ^a16 Is preferably a hydrogen atom or a hydroxyl group. o1 is preferably an integer of 0 to 3, more preferably 0 or 1.

The monomer represented by the formula (a2-1) includes, for example, the following. Among them, 3-hydroxy-1-adamantyl (meth) acrylate, 3,5-dihydroxy-1-adamantyl (meth) acrylate, and (meth) Adamantyloxycarbonyl) methyl is preferable, and 3-hydroxy-1-adamantyl (meth) acrylate and 3,5-dihydroxy-1-adamantyl (meth) More preferred are 3-hydroxy-1-adamantyl methacrylate and 3,5-dihydroxy-1-adamantyl methacrylate.

The content of the structural unit derived from the monomer represented by the formula (a2-1) in the resin is generally from 3 to 40 mol%, preferably from 5 to 35 mol% in the total structural units of the resin, Is 5 to 30 mol%.

≪ Acid-stable monomers containing a lactone ring >

The lactone ring possessed by the acid-stable monomer may be a single ring such as, for example, a? -Propiolactone ring,? -Butyrolactone ring or? -Valerolactone ring, and may be a monocyclic ring such as a ring- It may be a ring. Of these lactone rings, condensation rings of? -Butyrolactone rings and? -Butyrolactone rings with other rings are preferable.

The acid stable monomer having a lactone ring is represented by, for example, formula (a3-1), formula (a3-2), or formula (a3-3). One of these may be used alone, or two or more of them may be used in combination.

Among the formulas (a3-1) to (a3-3), L ^{a4 to} L ^a6 Are each independently, -O- or -O- (CH _{2) k3} represents -CO-O-, k3 is an integer of 1 to 7. Each of R ^a18 to R ^a20 independently represents a hydrogen atom or a methyl group. R ^a21 C ₁ -C ₄ P1 represents an integer of 0 to 5; R ^a22 and R ^a23 Are, each independently, a carboxyl group, a cyano group or a C ₁ ~C ₄ And q1 and r1 each independently represent an integer of 0 to 3;

Examples of L ^{a4 to} L ^a6 include those described for L ^a3 . Each of L ^{a4 to} L ^a6 is preferably independently -O- or -O- (CH ₂ ) _{d 1} -CO-O- (wherein d 1 is an integer of 1 to 4), more preferably -O - to be. -O- and the like listed in L ^{a4 to} L ^a6 are each bonded to -CO- of the formulas (a3-1) to (a3-3) on the left side and bonded to the lactone ring on the right side. R ^a18 to R ^a20 are preferably methyl groups. R ^a21 is preferably a methyl group. R ^a22 and R ^a23 Are each independently preferably a carboxyl group, a cyano group or a methyl group. p1 to r1 are each independently preferably 0 to 2, more preferably 0 or 1.

Examples of the monomer represented by the formula (a3-1) include the following.

The monomer represented by the formula (a3-2) includes, for example, the following.

The monomer represented by the formula (a3-3) includes, for example, the following.

Among the acid-stable monomers having a lactone ring, (meth) acrylic acid (5-oxo-4-oxatricyclo [4.2.1.0 ^3,7 ] (5-oxo-4-oxatricyclo [4.2.1.0 ^3,7 ] nonan- ² -yloxy) -2-oxoethyl is preferable, and methacrylic acid (5-oxo- 4-oxatricyclo [4.2.1.0 ^3,7 ] nonan-2-yl methacrylate, tetrahydro-2-oxo-3-furyl methacrylate, 2- 0.0 > ^3,7 ] nonan- ² -yloxy) -2-oxoethyl < / RTI >

The content of the structural unit derived from the monomer represented by the formula (a3-1), the formula (a3-2) or the formula (a3-3) in the resin is generally 5 to 50 mol% in the total structural units of the resin , Preferably 10 to 45 mol%, and more preferably 15 to 40 mol%.

<Other acid stable monomers>

Examples of other acid-stable monomers include maleic anhydride represented by the formula (a4-1), itaconic anhydride represented by the formula (a4-2), or a norbornene ring represented by the formula (a4-3) And the like.

In the formula (a4-3)

R ^a25 and R ^a26 Each independently represent a hydrogen atom, a substituent (e.g. a hydroxyl group) represent a carbon number of 1 to 3 aliphatic hydrocarbon group, a cyano group, a carboxyl group, or alkoxycarbonyl group (-COOR ^a27) of which may have, or R ^a25 And R ^a26 are bonded to each other to form -CO-O-CO-, and R ^a27 Represents a C ₁ to C ₃₆ aliphatic hydrocarbon group or a C _{3 to} C ₃₆ saturated cyclic hydrocarbon group, and -CH ₂ - of an aliphatic hydrocarbon group and a saturated cyclic hydrocarbon group may be substituted with -O- or CO-. Except that -COOR ^a27 is an acid labile group (i.e., R ^a27 Does not include that the tertiary carbon atom is bonded to -O-).

Examples of the aliphatic hydrocarbon group which may have a substituent represented by R ^a25 and R ^a26 include a methyl group, an ethyl group, a propyl group, a hydroxymethyl group and a 2-hydroxyethyl group. The carbon number of the aliphatic hydrocarbon group of R ^a27 is preferably 1 to 8, more preferably 1 to 6, and the carbon number of the saturated cyclic hydrocarbon group is preferably 4 to 36, more preferably 4 to 12 . Examples of R ^a27 include a methyl group, an ethyl group, a propyl group, a 2-oxo-oxolan-3-yl group and a 2-oxo-oxolan-4-yl group.

Examples of the monomer represented by the formula (a4-3) include 2-norbornene, 2-hydroxy-5-norbornene, 5-norbornene- Norbornene-2-carboxylic acid 2-hydroxy-1-ethyl, 5-norbornene-2-methanol and 5-norbornene-2,3-dicarboxylic acid anhydride, .

The content of the structural unit derived from the monomer represented by the formula (a4-1), the formula (a4-2) or the formula (a4-3) in the resin is usually 2 to 40 mol% in the total structural units of the resin , Preferably 3 to 30 mol%, and more preferably 5 to 20 mol%.

The preferred resin (A) is a copolymer obtained by polymerizing at least a monomer having an acid labile group, an acid stable monomer having a hydroxyl group and / or an acid stable monomer having a lactone ring. In this preferred copolymer, the monomer having an acid labile group is more preferably a monomer having at least one kind selected from the group consisting of a monomer represented by the formula (a1-1) and a monomer represented by the formula (a1-2) a1-1)). The acid-stable monomer having a hydroxy group is preferably a monomer represented by the formula (a2-1). The acid stable monomer having a lactone ring is more preferably at least one kind of a monomer represented by the formula (a3-1) and a monomer represented by the formula (a3-2).

The resin (A) can be produced by a known polymerization method (for example, a radical polymerization method).

 The weight average molecular weight of the resin (A) is preferably 2,500 or more (more preferably 3,000 or more) and 50,000 or less (more preferably 30,000 or less). The weight average molecular weight as referred to herein is determined by gel permeation chromatography analysis on the basis of standard polystyrene standards, and detailed analysis conditions of the analysis will be described in detail in the examples of the present application.

The content of the resin (A) is preferably 80% by mass or more of the solid content of the photoresist composition. In the present specification, &quot; solid content in the composition &quot; means the total of components other than the solvent in the photoresist composition. The solid content in the composition and the content of the resin (A) in the composition can be measured by a known analytical means such as liquid chromatography or gas chromatography.

&Lt; Basic compound >

The photoresist composition of the present invention may contain a basic compound. The content of the basic compound is preferably about 0.01 to 1% by mass based on the amount of the solid content of the photoresist composition.

The basic compound is preferably a basic nitrogen-containing organic compound (for example, an amine and an ammonium salt). The amine may be an aliphatic amine or an aromatic amine. The aliphatic amines can be either primary amines, secondary amines or tertiary amines. The aromatic amine may be an aromatic ring such as aniline, or an aromatic amine such as pyridine. As preferable basic compounds, aromatic amines represented by the formula (C2), particularly anilines represented by the formula (C2-1), may be mentioned.

Among the formulas (C2) and (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.

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 of the aliphatic hydrocarbon group, the saturated cyclic hydrocarbon group, the aromatic hydrocarbon group, or the alkoxy group may be substituted with a hydroxyl group, an amino group, or a C ₁ -C ₆ alkoxy group, and the amino group may be substituted with a C ₁ -C ₄ alkyl group Or may be substituted.

The aliphatic hydrocarbon group is preferably a group having 1 to 6 carbon atoms, the saturated cyclic hydrocarbon group is preferably a group having 5 to 10 carbon atoms, and the aromatic hydrocarbon group is preferably a group having 6 to 10 carbon atoms. The alkoxy group is preferably a C ₁ to C ₆ alkoxy group.

o represents an integer of 0 to 3; When o is 2 or more, a plurality of T ³ may be the same or different.

Examples of the aromatic amine (C2) include 1-naphthylamine and 2-naphthylamine.

Examples of the aniline (C2-1) include aniline, diisopropylaniline, 2-, 3- or 4-methylaniline, 4-nitroaniline, N-methylaniline, N, N-dimethylaniline and diphenylamine . Among them, diisopropylaniline (especially 2,6-diisopropylaniline) is preferable.

Examples of the basic compound include compounds represented by formulas (C3) to (C11).

Among the formulas (C3) to (C11)

T ¹ , T ² , T ³ and o are the same as above.

T ⁴ represents an aliphatic hydrocarbon group, a saturated cyclic hydrocarbon group or an alkanoyl group.

The aliphatic hydrocarbon group is preferably a group having 1 to 6 carbon atoms, the saturated cyclic hydrocarbon group is preferably a group having 3 to 6 carbon atoms, and the alkanoyl group is preferably a group having 2 to 6 carbon atoms.

u represents an integer of 0 to 8; When o or u is an integer of 2 or more, a plurality of T ³ Or T ⁴ May be the same or different from each other.

A is each independently, a divalent aliphatic hydrocarbon group (preferably an alkylene group), -CO-, -C (= NH ) -, -C (= NR 34) -, -S-, -SS-, or their .

The divalent aliphatic hydrocarbon group is preferably a group having 1 to 6 carbon atoms.

R ³⁴ represents a C ₁ -C ₄ alkyl group.

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, But are not limited to, triethylamine, trimethylamine, tripropylamine, tributylamine, tripentylamine, trihexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, methyldibutylamine, methyldipentylamine, methyl There may be mentioned aliphatic amines such as dihexylamine, methyldicyclohexylamine, methyldiheptylamine, methyldioctylamine, methyldinonylamine, methyldodecylamine, ethyldibutylamine, ethyldipentylamine, ethyldihexylamine, (2-methoxyethoxy) ethyl] amine, triisopropanolamine ethylenediamine, tetramethylenediamine, hexamethylenediamine, tetramethylenediamine, tetramethylenediamine, , 4,4'-diamino-1,2-diphenylethane, 4,4'-diamino-3,3'-dimethyldiphenylmethane and 4,4'-diamino-3,3'-diethyldiphenylmethane.

As the compound (C4), piperazine can be mentioned.

As the compound (C5), morpholine can be mentioned.

Examples of the compound (C6) include piperidine and a hindered amine compound having a piperidine skeleton described in JP-A-11-52575.

Examples of the compound (C7) include 2,2'-methylenebis aniline.

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) Di (4-pyridyl) ethane, di (2-pyridyl) ketone, 4,4'- Dipyridyl sulfide, 4,4'-dipyridyl disulfide, 2,2'-dipyridyl amine and 2,2'-dipicolyl amine.

Examples of the compound (C11) include bipyridine.

Examples of the ammonium salt include tetramethylammonium hydroxide, tetraisopropylammonium hydroxide, tetrabutylammonium hydroxide, tetrahexylammonium hydroxide, tetraoctylammonium hydroxide, phenyltrimethylammonium hydroxide, 3- ( Trifluoromethyl) phenyltrimethylammonium hydroxide, tetra-n-butylammonium salicylate and choline.

<Solvent>

The photoresist composition of the present invention may contain a solvent in an amount of 90 mass% or more in the photoresist composition. The photoresist composition of the present invention containing a solvent is suitable for producing a thin film photoresist. The content of the solvent is 90 mass% or more (preferably 92 mass% or more, and more preferably 94 mass% or more) and 99.9 mass% or less (preferably 99 mass% or less) in the composition. The content of the solvent can be measured by a known analytical means such as liquid chromatography or gas chromatography.

Examples of the solvent 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; Chain esters such as ethyl lactate, butyl acetate, amyl acetate and ethyl pyruvate; Ketones such as acetone, methyl isobutyl ketone, 2-heptanone, and cyclohexanone; cyclic esters such as? -butyrolactone; . The solvent may be used alone, or two or more solvents may be used in combination.

&Lt; Other components >

The photoresist composition of the present invention may contain other components as required. Such other components are not limited, and additives known in the photoresist field can be used, for example, a sensitizer, a dissolution inhibiting agent, a surfactant, a stabilizer, a dye and the like.

&Lt; Photoresist composition and preparation method thereof >

The photoresist composition of the present invention can be prepared by mixing the resin, the acid generator and the solvent of the present invention, or by mixing the resin, the acid generator of the present invention, a basic compound and a solvent. In such a mixing, the order of mixing is arbitrary and not limited. A suitable temperature range can be selected from the range of, for example, 10 to 40 占 폚, depending on the kind of the resin and the like, the solubility in a solvent such as a resin, and the like. The mixing time may be selected from 0.5 to 24 hours, depending on the mixing temperature. The mixing means is not particularly limited, and stirring mixing or the like may be used.

For example, the resin, the acid generator and the solvent of the present invention, and the basic compound or other components to be used, if necessary, are each mixed in a desired amount, and then the mixture is mixed with a solution having a pore diameter of about 0.2 탆 By filtering the mixed solution, the photoresist composition of the present invention can be prepared.

&Lt; Method for producing photoresist pattern >

The method for producing a photoresist pattern of the present invention comprises:

(1) a step of applying the above-mentioned photoresist composition of the present invention onto a substrate to form a photoresist composition layer,

(2) a step of drying the formed photoresist composition layer to form a photoresist film,

(3) a step of exposing the photoresist film,

(4) a step of heating the photoresist film after exposure, and

(5) a step of developing the photoresist film after heating.

The coating of the photoresist composition in a gas phase can be carried out by a commonly used apparatus such as a spin coater.

In the step of drying the photoresist composition layer to remove the solvent, the removal of the solvent is carried out by evaporating the solvent using a heating device such as a hot plate, or by using a pressure reducing device, Thereby forming a photoresist film. The drying temperature may be about 50 to 200 占 폚. The pressure may be about 1 to 1.0 x 10 &lt; ⁵ &gt; Pa.

The obtained photoresist film is exposed using an exposure machine. At this time, a liquid immersion exposure apparatus may be used. Normally, exposure is performed via a mask corresponding to the required photoresist pattern. Examples of the exposure light source include those emitting ultraviolet laser light such as KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), F ₂ laser (wavelength 157 nm), solid laser light source Laser, or the like), and radiating a harmonic laser beam of an out-of-gamut or vacuum ultraviolet region.

The exposed photoresist film is heated. The heating temperature is usually about 50 to 200 占 폚, preferably about 70 to 150 占 폚.

The photoresist film after heating is optionally developed using a developing device, usually using an alkali developing solution. The alkaline developer used herein may be any of various alkaline aqueous solutions used in this field. For example, an aqueous solution of tetramethylammonium hydroxide or (2-hydroxyethyl) trimethylammonium hydroxide (commonly referred to as choline) may, for example, be mentioned.

After development, it is preferable to rinse with ultrapure water to remove the water remaining on the substrate and the pattern.

<Applications>

The photoresist composition of the present invention is particularly useful as a chemically amplified photoresist composition and is suitably used in a wide range of applications such as microfabrication of semiconductors, production of circuit boards such as liquid crystal, thermal heads, and other photofabrication processes . Particularly, in view of the fact that the occurrence of defects can be suppressed and the resolution, shape and line edge roughness of the resulting pattern can be further improved, it is possible to use an excimer laser lithography such as ArF or KrF and ArF liquid immersion lithography, , And can be used as chemically amplified photoresist compositions suitable for EUV exposure lithography. In addition to immersion exposure, it can also be used in dry exposure.

[Example]

Hereinafter, the present invention will be described in detail with reference to examples.

In Examples and Comparative Examples,% and parts representing the content and amount of use are on a mass basis unless otherwise specified.

The weight average molecular weight is a value obtained by gel permeation chromatography (HLC-8120GPC type, manufactured by TOSO CORPORATION, column: "TSKgel Multipore HXL-M", three solvents, tetrahydrofuran) using polystyrene as a standard product.

Column: TSKgel Multipore H _XL -Mx3 + guardcolumn (manufactured by Tosoh Corporation)

Eluent: tetrahydrofuran

Flow rate: 1.0 mL / min

Detector: RI detector

Column temperature: 40 DEG C

Injection volume: 100 μl

Molecular weight standard: Standard polystyrene (manufactured by Tosoh Corporation)

The structure of the compound was confirmed by mass analysis (LC: Agilent Model 1100, MASS: Agilent LC / MSD type or LC / MSD TOF type).

Example 1

, 12.16 parts of sodium hydride, 400 parts of toluene and 41.48 parts of a compound represented by the formula (II-1) (2,10-camphor sultam, purchased from Aldrich) were mixed. The resulting mixture was stirred at 23 占 폚 for 30 minutes, and then 25.69 parts of a compound represented by the formula (III-1) (chloroacetyl chloride, purchased from Tokyo Chemical Industry Co., Ltd.) was added. The resulting mixture was stirred at 23 占 폚 for 20 hours. 200 parts of ion-exchanged water and 300 parts of ethyl acetate were added to the obtained reaction mixture, followed by stirring at 23 占 폚 for 30 minutes, followed by liquid separation. To the obtained organic layer, 92 parts of a 1M aqueous solution of sodium hydrogencarbonate was added and stirred at 23 DEG C for 30 minutes, followed by liquid separation. 180 parts of ion-exchanged water was added to the obtained organic layer, followed by stirring at 23 占 폚 for 30 minutes, followed by liquid separation. This water washing was carried out three times. After the obtained organic layer was concentrated, 130 parts of methanol was added to the concentrated residue, and the mixture was stirred at 23 DEG C for 30 minutes and filtered to obtain 24.21 parts of a compound represented by the formula (IV-1).

The salt represented by the formula (V-1) was synthesized by the method described in JP-A-2008-127367.

4.98 parts of the salt represented by the formula (V-1) and 30.02 parts of N, N-dimethylformamide were mixed. The resulting mixture was stirred at 23 占 폚 for 30 minutes, and then 1.57 parts of calcium carbonate and 0.47 part of potassium iodide were added. The resulting mixture was stirred at 40 占 폚 for 30 minutes. To the obtained mixture, 3.15 parts of the compound represented by the formula (IV-1) was added. The resulting mixture was stirred at 40 占 폚 for 6 hours, then cooled to 23 占 폚, and then 170 parts of chloroform and 32 parts of 5% oxalic acid aqueous solution were added. The resulting mixture was stirred at 23 占 폚 for 30 minutes, and then separated. 67 parts of ion-exchanged water was added to the obtained organic layer, followed by stirring at 23 占 폚 for 30 minutes, followed by liquid separation. This water washing operation was repeated three times. 1.00 parts of activated carbon was added to the obtained organic layer, stirred at 23 캜 for 30 minutes, and then filtered. The filtrate was concentrated, and 15.00 parts of acetonitrile was added to the concentrate to dissolve. The resulting solution was concentrated. To the residue, 37 parts of ethyl acetate was added, and the resulting mixture was stirred and then the supernatant was removed. To the obtained residue, 37 parts of tert-butyl methyl ether was added, and the resulting mixture was stirred, and then the supernatant was removed. The obtained residue was dissolved in chloroform, and the resulting solution was concentrated to obtain 3.02 parts of a salt represented by the formula (I-1) as a white solid. The resulting salt is referred to as acid generator I1.

MS (ESI (+) Spectrum): M ⁺ 263.1

MS (ESI (-) Spectrum): M ^- 430.0

Example 2

A mixture of 10.4 parts of lithium aluminum hydride and 120 parts of anhydrous tetrahydrofuran was stirred at 23 占 폚 for 30 minutes. To this, a solution obtained by dissolving 62.2 parts of the salt represented by the formula (VI-2) in 900 parts of anhydrous tetrahydrofuran was added dropwise under ice-cooling. The resulting mixture was stirred at 23 占 폚 for 5 hours. To the resulting reaction mixture, 50.0 parts of ethyl acetate and 50.00 parts of 6N hydrochloric acid were added, stirred, and liquid separation was carried out. The obtained organic layer was concentrated and then the residue was purified by column purification (silica gel: silica gel 60-200 mesh, Merck; developing solvent: chloroform / methanol = 5/1) to obtain 84.7 parts of a salt represented by the formula (VII- (Purity: 60%).

16.91 parts of the compound represented by the formula (III-2) and 500 parts of anhydrous tetrahydrofuran were mixed, and the resulting mixture was stirred at 23 占 폚 for 30 minutes. To this, a mixed solution of 28.90 parts of carbonyldiimidazole and 500 parts of anhydrous tetrahydrofuran was added dropwise at 23 占 폚. The resulting mixture was stirred at 23 占 폚 for 4 hours. The obtained reaction mixture was added dropwise to a mixed solution of 60.40 parts (purity: 60%) of the salt represented by the formula (VII-2) and 500 parts of anhydrous tetrahydrofuran at 54 to 60 ° C over 30 minutes. The resulting mixture was heated at 60 占 폚 for 18 hours. After cooling, the mixture was filtered, and the filtrate was concentrated. 15.42 parts of a salt represented by the formula (VIII-2) was obtained by subjecting the concentrate to column purification (silica gel: silica gel 60-200 mesh, manufactured by Merck Ltd., developing solvent: chloroform / methanol = 5/1).

3.04 parts of sodium hydride, 100 parts of toluene and 10.37 parts of a compound represented by the formula (II-2) (2,10-camphorsultam, purchased from Aldrich) were mixed. After the resulting mixture was stirred at 23 占 폚 for 30 minutes, 14.82 parts of the compound represented by the formula (VIII-2) was added. The resulting mixture was stirred at 23 占 폚 for 20 hours. 50 parts of ion-exchanged water and 100 parts of ethyl acetate were added to the obtained reaction mixture, and the mixture was stirred at 23 占 폚 for 30 minutes, followed by liquid separation. The obtained organic layer was concentrated, and then the residue was subjected to column purification (silica gel: silica gel 60-200 mesh, Merck Ltd., developing solvent: chloroform / methanol = 5/1) to obtain 12.86 parts of a compound represented by the formula (IX-2) .

12.16 parts of the salt represented by the formula (IX-2), 300 parts of chloroform and 100 parts of ion-exchanged water was stirred at 23 DEG C for 30 minutes. To this, 8.30 parts of a salt represented by the formula (X-2) was added, and the resulting mixture was stirred at 23 占 폚 for 12 hours, and liquid separation was carried out. 100 parts of ion-exchanged water was added to the organic layer, and water was washed. This water washing operation was performed three times. 3.00 parts of activated carbon was added to the obtained organic layer, stirred at 23 DEG C for 30 minutes, and filtered. After the filtrate was concentrated, 200 parts of acetonitrile was added to the concentrate to dissolve it. After the obtained solution was concentrated, 200 parts of ethyl acetate was added to the residue. After the obtained mixture was stirred, the supernatant was removed. To the obtained residue, 200 parts of tert-butyl methyl ether was added, and the resulting mixture was stirred and then the supernatant was removed. The obtained residue was dissolved in chloroform, and the concentrate was subjected to column purification (silica gel: silica gel 60-200 mesh, manufactured by Merck Ltd., eluent: chloroform / methanol = 5/1) Was obtained. The resulting salt is referred to as acid generator I2.

MS (ESI (+) Spectrum): M ⁺ 263.1

MS (ESI (-) Spectrum): M ^- 416.1

Example 3

5.46 parts of a salt represented by the formula (V-3) and 30 parts of N, N-dimethylformamide was stirred at 23 DEG C for 30 minutes, and then 1.57 parts of calcium carbonate and 0.47 part of potassium iodide were added. The resulting mixture was stirred at 40 占 폚 for 30 minutes, and then 3.15 parts of a compound represented by the formula (IV-1) was added. The obtained mixture was stirred at 40 占 폚 for 6 hours, cooled to 23 占 폚, and then 150 parts of chloroform and 35 parts of 5% oxalic acid aqueous solution were added. The resulting mixture was stirred at 23 占 폚 for 30 minutes, and then separated. 75 parts of ion-exchanged water was added to the obtained organic layer, followed by stirring at 23 占 폚 for 30 minutes, followed by liquid separation. This water washing operation was repeated three times. 1.00 parts of activated carbon was added to the obtained organic layer, stirred at 23 캜 for 30 minutes, and then filtered. The filtrate was concentrated, and 15 parts of acetonitrile was added to the concentrate to dissolve. After the obtained solution was concentrated, 40 parts of ethyl acetate was added to the residue. After the obtained mixture was stirred, the supernatant was removed. To the resulting residue was added 40 parts of tert-butyl methyl ether. After the obtained mixture was stirred, the supernatant was removed. The obtained residue was dissolved in chloroform and concentrated to obtain 3.48 parts of a salt represented by the formula (I-3). The resulting salt is referred to as acid generator I3.

MS (ESI (+) Spectrum): M ⁺ 305.1

MS (ESI (-) Spectrum): M ^- 430.0

Example 4

A mixture of 5.18 parts of the salt represented by the formula (V-4) and 30 parts of N, N-dimethylformamide was stirred at 23 DEG C for 30 minutes, and then 1.57 parts of calcium carbonate and 0.47 part of potassium iodide were added. The resulting mixture was stirred at 40 占 폚 for 30 minutes. To the obtained mixture, 3.15 parts of the compound represented by the formula (IV-1) was added. The resulting mixture was stirred at 40 占 폚 for 6 hours, then cooled to 23 占 폚, and then 150 parts of chloroform and 35 parts of 5% oxalic acid aqueous solution were added. The resultant mixture was stirred at 23 占 폚 for 30 minutes and separated. 75 parts of ion-exchanged water was added to the obtained organic layer, followed by stirring at 23 占 폚 for 30 minutes, followed by liquid separation. This water washing operation was repeated three times. 1.00 parts of activated carbon was added to the obtained organic layer, stirred at 23 캜 for 30 minutes, and then filtered. The filtrate was concentrated, and 15 parts of acetonitrile was added to the concentrate to dissolve. The obtained solution was concentrated, and 40 parts of ethyl acetate was added to the residue and stirred. The supernatant was removed from the resulting mixture. To the obtained residue, 40 parts of tert-butyl methyl ether was added, and the resulting mixture was stirred and then the supernatant was removed. The obtained residue was dissolved in chloroform and concentrated to obtain 2.14 parts of a salt represented by the formula (I-4). The resulting salt is referred to as acid generator I4.

MS (ESI (+) Spectrum): M ⁺ 281.0

MS (ESI (-) Spectrum): M ^- 430.0

Example 5

4.34 parts of a salt represented by the formula (V-5) and 30 parts of N, N-dimethylformamide was stirred at 23 占 폚 for 30 minutes, and then 1.57 parts of calcium carbonate and 0.47 part of potassium iodide were added. After the resulting mixture was stirred at 40 占 폚 for 30 minutes, 3.15 parts of the compound represented by the formula (IV-1) was added. The obtained mixture was stirred at 40 占 폚 for 6 hours, cooled to 23 占 폚, and then 150 parts of chloroform and 35 parts of 5% oxalic acid aqueous solution were added. The resulting mixture was stirred at 23 占 폚 for 30 minutes, and then separated. 75 parts of ion-exchanged water was added to the obtained organic layer, followed by stirring at 23 占 폚 for 30 minutes, followed by liquid separation. This water washing operation was repeated three times. 1.00 parts of activated carbon was added to the obtained organic layer, stirred at 23 캜 for 30 minutes, and then filtered. The filtrate was concentrated, and 15 parts of acetonitrile was added to the concentrate to dissolve. The resulting solution was concentrated, and 40 parts of ethyl acetate was added to the residue. After the obtained mixture was stirred, the supernatant was removed. To the resulting residue was added 40 parts of tert-butyl methyl ether. After the obtained mixture was stirred, the supernatant was removed. The resulting residue was dissolved in chloroform. The obtained solution was concentrated to obtain 1.64 parts of a salt represented by the formula (I-5). The resulting salt is referred to as acid generator I5.

MS (ESI (+) Spectrum): M ⁺ 207.1

MS (ESI (-) Spectrum): M ^- 430.0

The monomers used in the following Synthesis Examples are shown below.

Synthesis Example 1

Monomer D, monomer E, monomer B, monomer C and monomer F were mixed at a molar ratio of 30: 14: 6: 20: 30. To the resulting mixture, 1,4-dioxane was added in an amount of 1.5 times the mass of the total monomer. To the obtained mixture, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as polymerization initiators were added at a ratio of 1.00 mol% and 3.00 mol% to the total moles of the total monomers, respectively. The resulting mixture was heated at 73 占 폚 for about 5 hours. Then, the reaction mixture was poured into a large amount of a mixed solvent of methanol and water (4: 1), and the resulting copolymer was precipitated. The precipitated copolymer was taken out and purified three times by pouring into a large amount of a mixed solvent of methanol and water (4: 1) to obtain a copolymer having a weight average molecular weight of about 8.1 x 10 ³ in a yield of 65% . The obtained copolymer had the following structural unit, which was referred to as Resin A1.

Synthesis Example 2

Monomer A, monomer B and monomer C were mixed in a molar ratio of 50: 25: 25. To the resulting mixture, 1,4-dioxane was added in an amount of 1.5 times the mass of the total monomer. To the obtained mixture, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added in a proportion of 1 mol% and 3 mol%, respectively, to the total number of moles of the total monomers. The resulting mixture was heated at 80 占 폚 for about 8 hours. Thereafter, the reaction mixture was poured into a large amount of a mixed solvent of methanol and water (3: 1), and the resulting copolymer was precipitated. The precipitated copolymer was taken out and poured into a large amount of a mixed solvent of methanol and water (3: 1) three times to obtain a copolymer having a weight average molecular weight of about 8.0 x 10 ³ in a yield of 60% . This copolymer has the following structural unit, which is referred to as Resin A2.

(Preparation of photoresist composition)

The components shown below were mixed in the composition shown in Table 1, and the obtained solution was filtered with a filter made of a fluororesin having a pore size of 0.2 mu m to prepare a photoresist composition.

<Resin>

Resins A1, A2

<Acid Generator>

Acid generators I1, I2, I3, I4, I5

Acid generator B1

Acid generator B2

Acid generator B3

&Lt; Basic compound: Querche &

C1: 2,6-diisopropylaniline

<Solvent>

Propylene glycol monomethyl ether acetate 265 parts

2-heptanone 20.0 parts

Propylene glycol monomethyl ether 20.0 parts

3.5 parts of? -butyrolactone

(Evaluation of photoresist composition for immersion exposure)

On a 12-inch silicon wafer, a composition for an organic anti-reflective film [ARC-29; Manufactured by Nissan Chemical Industries, Ltd.) was applied and baked under the conditions of 205 DEG C for 60 seconds to form an organic antireflection film having a thickness of 780 ANGSTROM.

Subsequently, the above-prepared photoresist composition was spin-coated on the formed organic anti-reflective film so that the film thickness after drying was 85 nm.

The obtained silicon wafer was pre-baked on a direct hot plate at a temperature indicated in the column of &quot; PB &quot; in Table 1 for 60 seconds. The wafer on which the photoresist film was formed in this manner was immersed in an ArF excimer stepper for liquid immersion lithography (XT: 1900Gi; Manufactured by ASML, NA = 1.35, 3/4 Annular X-Y polarized light) was used to immerse the line-and-space pattern by immersion exposure.

After exposure, a post-exposure bake was performed on a hot plate at a temperature listed in the column of &quot; PEB &quot; in Table 1 for 60 seconds.

Then, paddle development was performed for 60 seconds with a 2.38 mass% tetramethylammonium hydroxide aqueous solution.

Effective sensitivity: The exposure amount at which the exposure amount at which the line-and-space pattern of 50 nm becomes 1: 1 in each photoresist film is defined as the effective sensitivity.

Line edge roughness evaluation (LER): The wall surface of the photoresist pattern after the lithography process was observed with a scanning electron microscope to find that the deviation width of the irregularities of the side walls of the photoresist pattern was 4.5 nm or less,? 4.5 nm and 5 nm Or less and those exceeding 5 nm were evaluated as x. The numerical values in parentheses indicate the deviation width (nm) of the unevenness of the sidewall of the resist pattern. These results are shown in Table 2.

From the resist composition containing the salt of the present invention, a resist pattern having excellent line edge roughness can be obtained.

Claims (12)

Formula (I):

Wherein R ¹ and R ² independently of one another represent a fluorine atom or a C ₁ -C ₆ perfluoroalkyl group.
X ¹ is represented by the formula (X1):

(Wherein mx represents an integer of 0 or 1, X ¹¹ represents a C ₁ to C ₁₄ saturated hydrocarbon group, and * represents a bonding site to -C (R ¹ ) (R ² ) -)
, Or a group represented by -CH ₂ -O-CO-CH ₂ -
Z &lt; ^{1 +} &gt; represents the formula (b2-1) to (b2-4):

(In the formula (b2-1), R ^b4 to R ^b6 independently represent a C ₁ to C ₃₀ aliphatic hydrocarbon group, a C _{3 to} C ₃₆ saturated cyclic hydrocarbon group, or a C _{6 to} C ₁₈ aromatic hydrocarbon group. The hydrocarbon group may be substituted with a hydroxyl group, a C _{1 to} C ₁₂ alkoxy group, or a C _{6 to} C ₁₈ aromatic hydrocarbon group, and the saturated cyclic hydrocarbon group may be substituted with a halogen atom, a C _{2 to} C ₄ acyl group or a glycidyloxy group And the aromatic hydrocarbon group may be substituted with a halogen atom, a hydroxyl group, a C _{1 to} C ₃₆ aliphatic hydrocarbon group, a C _{3 to} C ₃₆ saturated cyclic hydrocarbon group or a C _{1 to} C ₁₂ alkoxy group.
In formula (b2-2), R ^b7 and R ^b8 each independently represent a hydroxyl group, a C _{1 to} C ₁₂ aliphatic hydrocarbon group or a C _{1 to} C ₁₂ alkoxy group. m2 and n2 each independently represent an integer of 0 to 5;
In formula (b2-3), R ^b9 and R ^b10 each independently represent a C ₁ to C ₃₆ aliphatic hydrocarbon group or a C _{3 to} C ₃₆ saturated cyclic hydrocarbon group.
R ^b11 represents a hydrogen atom, a C _{1 to} C ₃₆ aliphatic hydrocarbon group, a C _{3 to} C ₃₆ saturated cyclic hydrocarbon group, or a C _{6 to} C ₁₈ aromatic hydrocarbon group.
R ^b12 represents a C ₁ to C ₁₂ aliphatic hydrocarbon group, a C _{3 to} C ₁₈ saturated cyclic hydrocarbon group, or a C _{6 to} C ₁₈ aromatic hydrocarbon group. The aromatic hydrocarbon group is optionally C ₁ ~C ₁₂ aliphatic hydrocarbon group, C ₁ ~C ₁₂ alkoxy group, C ₃ ~C ₁₈ saturated ring group optionally substituted hydrocarbon group or an alkylcarbonyloxy. R ^b9 and R ^b10, and R ^b11 and R ^b12 each independently may combine with each other to form a 3-membered to 12-membered ring, and at least one -CH ₂ - contained in these rings may be replaced by -O-, -S-, or -CO-.
In the formula (b2-4), R ^b13 to R ^b18 each independently represent a hydroxyl group, a C _{1 to} C ₁₂ aliphatic hydrocarbon group or a C _{1 to} C ₁₂ alkoxy group.
L ^b11 represents -S- or -O-. o2, p2, s2 and t2 each independently represent an integer of 0 to 5, q2 and r2 each independently represent an integer of 0 to 4, and u2 represents 0 or 1.)
Lt; 1 &gt; The method according to claim 1,
Wherein X ¹ represents * -CO-O-CH ₂ -CO- or -CH ₂ -O-CO-CH ₂ - (* represents a bonding site with -C (R ¹ ) (R ² ) -). delete An acid generator containing a salt according to claim 1. A photoresist composition comprising the acid generator according to claim 4 and a resin. 6. The method of claim 5,
A photoresist composition further comprising an acid generator different from the salt represented by the formula (I). The method according to claim 6,
The acid generator which is different from the salt represented by the formula (I)

Wherein Q ¹ and Q ² each independently represent a fluorine atom or a C ₁ -C ₆ perfluoroalkyl group. L ^b1 represents a single bond or a divalent C ₁ -C ₁₇ saturated hydrocarbon group, and -CH ₂ - contained in the divalent saturated hydrocarbon group may be substituted with -O- or -CO-. Y represents a C ₁ -C ₁₈ aliphatic hydrocarbon group which may have a substituent or a C ₃ -C ₁₈ saturated cyclic hydrocarbon group which may have a substituent, and the -CH ₂ - group contained in the aliphatic hydrocarbon group and the saturated cyclic hydrocarbon group, May be substituted with -O-, -SO ₂ - or -CO-. And Z ⁺ represents an organic cation. 8. The method of claim 7,
L ^b1 And * represents -CO-O- (* represents a bonding site with -C (Q ¹ ) (Q ² ) -). 8. The method of claim 7,
And Z ^& lt ^{; + &gt;} is triarylsulfonium cation. 6. The method of claim 5,
Wherein the resin has an acid labile group, is insoluble or hardly soluble in an aqueous alkali solution, and is soluble in an alkali aqueous solution by the action of an acid. 6. The method of claim 5,
Further, a photoresist composition containing a basic compound. (1) a step of applying the photoresist composition described in (5) on a substrate to form a photoresist composition layer,
(2) a step of drying the formed photoresist composition layer to form a photoresist film,
(3) a step of exposing the photoresist film,
(4) a step of heating the photoresist film after exposure, and
(5) A method for manufacturing a photoresist pattern, comprising the step of developing the photoresist film after heating.