JP5992658B2 - Salt and resist composition - Google Patents

Description

  The present invention relates to a salt and a resist composition.

  A chemically amplified resist composition used for fine processing of a semiconductor using a lithography technique contains an acid generator composed of a compound that generates an acid upon exposure.

As an acid generator, a salt represented by the following formula has been proposed (for example, Patent Document 1).

JP 2008-107817 A

  However, conventional acid generators may not always satisfy the resolution of a pattern formed using a resist composition containing an acid generator.

The present application includes the following inventions.
[1] A salt represented by the formula (I).
[In the formula (I),
Q ¹ and Q ² each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group.
X ¹ represents a saturated hydrocarbon group having a single bond or a substituted carbon atoms, which may based on have 1-17, also methylene groups contained in the saturated hydrocarbon group are replaced by an oxygen atom or a carbonyl group Good.
Y ¹ represents a linear or branched aliphatic hydrocarbon group having 1 to 36 carbon atoms, an alicyclic hydrocarbon group having 3 to 36 carbon atoms, or an aromatic hydrocarbon group having 6 to 36 carbon atoms, The aliphatic hydrocarbon group, alicyclic hydrocarbon group and aromatic hydrocarbon group may have a substituent, and the aliphatic hydrocarbon group, alicyclic hydrocarbon group and aromatic hydrocarbon group The methylene group contained in may be replaced with an oxygen atom or a carbonyl group.
R ^{e1 to} R ^e13 each independently represent a hydrogen atom, a halogen atom or a substituent, or two adjacent ones of R ^{e1 to} R ^e13 may be bonded to form a ring.
Z represents a single bond or a divalent linking group.
However, the salt represented by the formula (I) does not contain a vinyl group, an acryloyl group, a methacryloyl group, an acryloyloxy group or a methacryloyloxy group. ]

[2] The salt according to [1], wherein Z is a single bond.
[3] The salt according to [1] or [2], wherein X ¹ is —CO—O— [CH ₂ ] _h — (h represents an integer of 0 to 10).
[4] The salt according to any one of [1] to [3], wherein Y ¹ is a group represented by formula (Y1) or formula (Y2).
[In Formula (Y1) and Formula (Y2),
The hydrogen atom contained in the ring is a halogen atom, a hydroxyl group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, or glycidyl. It may be substituted with an oxy group or an acyl group having 2 to 4 carbon atoms, and the methylene group contained in the ring may be replaced with a carbonyl group or an oxygen atom.
* Represents a bond to ^{X 1.} ]

[5] An acid generator containing the salt according to any one of [1] to [4].
[6] The acid generator according to [5] above and a resin, wherein the resin has an acid labile group and is insoluble or hardly soluble in an alkaline aqueous solution, Resist composition which resin is resin which can be dissolved with alkaline aqueous solution.
[7] A resist composition comprising the composition according to [6] above and a basic compound.

[8] (1) A step of applying the resist composition according to [6] or [7] on a substrate,
(2) a step of removing the solvent from the composition after coating to form 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 pattern forming method including a step of developing the heated composition layer using a developing device.

  According to the salt of the present invention, a pattern having excellent resolution can be formed using a resist composition containing the salt.

The salt of the present invention is represented by the formula (I) (hereinafter sometimes referred to as “salt (I)”).
[In the formula (I),
Q ¹ and Q ² each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group.
X ¹ represents a saturated hydrocarbon group having a single bond or a substituted carbon atoms, which may based on have 1-17, also methylene groups contained in the saturated hydrocarbon group are replaced by an oxygen atom or a carbonyl group Good.
Y ¹ represents a linear or branched aliphatic hydrocarbon group having 1 to 36 carbon atoms, an alicyclic hydrocarbon group having 3 to 36 carbon atoms, or an aromatic hydrocarbon group having 6 to 36 carbon atoms, The aliphatic hydrocarbon group, alicyclic hydrocarbon group and aromatic hydrocarbon group may have a substituent, and the aliphatic hydrocarbon group, alicyclic hydrocarbon group and aromatic hydrocarbon group The methylene group contained in may be replaced with an oxygen atom or a carbonyl group.
R ^{e1 to} R ^e13 each independently represent a hydrogen atom, a halogen atom or a substituent, or two adjacent ones of R ^{e1 to} R ^e13 may be bonded to form a ring.
Z represents a single bond or a divalent linking group.
However, the salt represented by the formula (I) does not contain a vinyl group, an acryloyl group, a methacryloyl group, an acryloyloxy group or a methacryloyloxy group. ]

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. Furthermore, each substituent can be a monovalent or divalent substituent depending on the binding site.
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.

  In the present specification, the perfluoroalkyl group includes a perfluoromethyl group, a perfluoroethyl group, a perfluoro-n-propyl group, a perfluoroisopropyl group, a perfluoro-n-butyl group, a perfluoro-sec-butyl group, and a perfluoro-tert-butyl group. Group, perfluoro-n-pentyl group, perfluoro-n-hexyl group and the like. Of these, a perfluoromethyl group is preferable.

Examples of the saturated hydrocarbon group include divalent groups including an alkylene group and a cycloalkylene group.
Examples of the alkylene group include a methylene group, a dimethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, a heptamethylene group, an octamethylene group, a nonamethylene group, a decamethylene group, an undecamethylene group, and a dodecamethylene group. , Tridecamethylene group, tetradecamethylene group, pentadecamethylene group, hexadecamethylene group, heptacamethylene group, ethylene group, propylene group, isopropylene group, sec-butylene group and tert-butylene group.

Examples of the divalent group containing a cycloalkylene group include groups represented by the formula (X ¹ -A) to the formula (X ¹ -C).
[In the formula (X ¹ -A) to formula (X ¹ -C),
X ^1A and X ^1B each independently represent an alkylene group having 1 to 6 carbon atoms which may have a substituent. However, the number of carbon atoms of the group represented by the formula ^(X 1 -A) ~ Formula ^(X 1 -C) is 1 to 17. ]

Examples of the linear or branched aliphatic hydrocarbon group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, and an n-pentyl group. , N-hexyl group, heptyl group, 2-ethylhexyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group and other alkyl groups.
Examples of the alicyclic hydrocarbon group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclononyl group, a cyclodecyl group, a norbornyl group, a 1-adamantyl group, and a 2-adamantyl group. And cycloalkyl groups such as isobornyl group.

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

In the anion of the salt represented by the formula (I), Q ¹ and Q ² are preferably each independently a fluorine atom or —CF ₃ , and both are more preferably a fluorine atom.

In addition, the methylene group contained in the saturated hydrocarbon group having 1 to 17 carbon atoms in X ¹ may be replaced with an oxygen atom or a carbonyl group.
Examples of the substituent for X ¹ include a halogen atom, a hydroxyl group, a carboxyl group, a linear or branched aliphatic hydrocarbon group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, and a carbon number. Examples thereof include an aromatic hydrocarbon group having 6 to 20 carbon atoms, an aralkyl group having 7 to 21 carbon atoms, a glycidyloxy group, and an acyl group having 2 to 4 carbon atoms.

Here, examples of the halogen atom include fluorine, chlorine, bromine and iodine atoms.
Examples of the aralkyl group include benzyl, phenethyl, phenylpropyl, trityl, naphthylmethyl group, naphthylethyl group, and the like.
Examples of the acyl group include acetyl, propionyl, butyryl and the like.

Specific examples of X ¹ include the following groups. Note that * represents a bond with C (Q1) (Q2).

X ¹ is suitably —CO—O—X ¹⁰ —, —CO—O—X ¹¹ —CO—O—, —X ¹¹ —O—CO—, —X ¹¹ —O—X ¹² —. And —CO—O—X ¹⁰ — and —CO—O—X ¹¹ —CO—O— are preferable. However, X < ¹⁰ >, X < ¹¹ > and X < ¹² > represent a C1-C15 alkylene group of a single bond, a linear or branched form mutually independently. Among _{them, -CO-O- [CH 2]} h - (h is an integer of 0) are preferred.

Examples of the substituent for Y ¹ include a halogen atom, a hydroxyl group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, and an aralkyl group having 7 to 12 carbon atoms. 1 or more selected from the group consisting of a glycidyloxy group or an acyl group having 2 to 4 carbon atoms. In particular, these substituents preferably do not contain a vinyl group, an acryloyl group, a methacryloyl group, an acryloyloxy group and a methacryloyloxy group.

  As an alkoxy group, a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, a sec-butoxy group, a tert-butoxy group, an n-pentoxy group, an n-hexoxy group, a heptoxy group, an octoxy group , 2-ethylhexoxy group, nonyloxy group, decyloxy group, undecyloxy group, dodecyloxy group and the like.

  Examples of the anion of the salt represented by the formula (I) include the following formula (IA), formula (IB), formula (IC), formula (ID) and the like. Among these, anions represented by formula (IA) and formula (IB) are suitable.

[In formula (IA), formula (IB), formula (IC) and formula (ID),
Q ¹ , Q ² and Y ¹ are the same as defined in formula (I).
X ¹⁰ , X ¹¹ and X ¹² each independently represent a single bond, a linear or branched alkylene group having 1 to 15 carbon atoms. ]

Y ¹ includes a group represented by the formula (Y0).
[In the formula (Y0),
Ring W ′ represents an alicyclic hydrocarbon group having 3 to 36 carbon atoms, and the methylene group contained in the alicyclic hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
R ^b is independently of each other a halogen atom, a hydroxyl group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, or glycidyl. An oxy group or an acyl group having 2 to 4 carbon atoms is represented.
x represents an integer of 0 to 8. When x is 2 or more, the plurality of R ^b may be the same or different.
R ^a represents a hydrogen atom or a linear or branched hydrocarbon group having 1 to 6 carbon atoms, or may be bonded to a carbon atom contained in the ring W ′ to form a ring. ]
The hydrocarbon includes a saturated or unsaturated hydrocarbon group, and as described above, an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, an aryl, an aralkyl group, or a combination thereof. Can be mentioned.

x preferably represents an integer of 0 to 6, more preferably an integer of 0 to 4.
Examples of the ring W ′ include the formula (W1) to the formula (W26). * Represents a bond to ^{X 1.}

Among these, Y ¹ is more preferably a group represented by the formula (Y1) or the formula (Y2).
[In Formula (Y1) and Formula (Y2),
The hydrogen atom contained in the ring is a halogen atom, a hydroxyl group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, or glycidyl. It may be substituted with an oxy group or an acyl group having 2 to 4 carbon atoms, and the methylene group contained in the ring may be replaced with a carbonyl group or an oxygen atom.
* Represents a bond to ^{X 1.} ]

Y ¹ is a group in which a hydrogen atom contained in ring W ′ is not substituted or substituted only with a hydrocarbon group (provided that the methylene group contained in ring W ′ is replaced by an oxygen atom). And a group substituted with a hydroxyl group or a group containing a hydroxyl group (excluding those having a lactone structure) and two adjacent methylene groups contained in the ring W ′ are replaced with an oxygen atom and a carbonyl group. A group having a lactone structure and a group having a ketone structure in which one methylene group contained in ring W ′ is replaced by a carbonyl group, and a hydrogen atom contained in ring W ′ is an aromatic hydrocarbon group or a group having an aromatic ring Examples include a substituted group and a group having an ether structure in which one methylene group contained in ring W ′ is replaced with an oxygen atom.

Hydrogen atoms contained in the ring W 'is been substituted only with one or a hydrocarbon group not substituted (methylene group contained in the hydrocarbon group may be replaced by an oxygen atom.) As Y ¹ is For example, the following groups are mentioned.

Examples of Y ¹ in which a hydrogen atom contained in ring W ′ is substituted with a hydroxyl group or a group containing a hydroxyl group (however, having no lactone structure) include the following groups.

Examples of Y ¹ having a lactone structure in which two adjacent methylene groups contained in ring W ′ are replaced by a carbonyl group and an oxygen atom include the following groups.

Examples of Y ¹ having a ketone structure in which one methylene group contained in ring W ′ is replaced with a carbonyl group include the following groups.

Examples of Y ¹ in which the hydrogen atom contained in the ring W ′ is substituted with an aromatic hydrocarbon group or a group having an aromatic ring include the following groups.

Examples of Y ¹ having an ether structure in which one methylene group contained in ring W ′ is replaced with an oxygen atom include the following groups.

Examples of the anion represented by the formula (IA) include the following.
In the formula (IA), an anion in which a hydrogen atom contained in the ring W ′ is substituted only with a hydrocarbon group (a methylene group contained in the hydrocarbon group may be replaced with an oxygen atom), for example, The following are mentioned.

  In the formula (IA), examples of the anion in which the hydrogen atom contained in the ring W ′ is substituted with a hydroxyl group or a group containing a hydroxyl group (but not having a lactone structure) include the following.

  In the formula (IA), examples of the anion having a lactone structure in which two adjacent methylene groups contained in the ring W ′ are replaced with an oxygen atom and a carbonyl group include the followings.

  In the formula (IA), examples of the anion having a ketone structure in which the methylene group contained in the ring W ′ is replaced with a carbonyl group include the followings.

  In formula (IA), examples of the anion in which the hydrogen atom contained in ring W ′ is substituted with an aromatic hydrocarbon group or a group having an aromatic ring include the following.

  In the formula (IA), examples of the anion having an ether structure in which the methylene group contained in the ring W ′ is replaced with an oxygen atom include the followings.

Examples of the anion represented by the formula (IB) include the following.
In formula (IB), the hydrogen atom contained in ring W ′ is not substituted or substituted only with a hydrocarbon group (the methylene group contained in ring W ′ may be replaced with an oxygen atom). Examples of such include the following.

  In formula (IB), examples of the anion in which the hydrogen atom contained in ring W ′ is substituted with a hydroxyl group or a group containing a hydroxyl group include the following.

  In the formula (IB), examples of the anion having a lactone structure in which two adjacent methylene groups contained in the ring W ′ are replaced with an oxygen atom and a carbonyl group include the followings.

  In the formula (IB), examples of the anion having a ketone structure in which one methylene group included in the ring W ′ is replaced with a carbonyl group include the followings.

  In the formula (IB), examples of the anion in which the hydrogen atom contained in the ring W ′ is substituted with an aromatic hydrocarbon group include the following.

Examples of the anion represented by the formula (IC) include the following.
In formula (IC), the hydrogen atom contained in ring W ′ is not substituted or substituted only with a hydrocarbon group (the methylene group contained in ring W ′ may be replaced with an oxygen atom). Examples of such include the following.

  In formula (IC), examples of the anion in which the hydrogen atom contained in ring W ′ is substituted with a hydroxyl group or a group containing a hydroxyl group include the following.

  In the formula (IC), examples of the anion having a ketone structure in which one methylene group contained in the ring W ′ is replaced with a carbonyl group include the followings.

Examples of the anion represented by the formula (ID) include the following.
In formula (ID), the hydrogen atom contained in ring W ′ is not substituted or substituted only with a hydrocarbon group (the methylene group contained in ring W ′ may be replaced with an oxygen atom). Examples of such include the following.

  In formula (ID), examples of the anion in which the hydrogen atom contained in ring W ′ is substituted with a hydroxyl group or a group containing a hydroxyl group include the following.

  Examples of the anion having a ketone structure in which one methylene group contained in the ring W ′ in the formula (ID) is replaced with a carbonyl group include the following.

The cation of the salt represented by the formula (I) is represented by the formula (EE).
[In the formula (EE)
R ^{e1 to} R ^e13 each independently represent a hydrogen atom, a halogen atom or a substituent, or two adjacent ones of R ^{e1 to} R ^e13 may be bonded to form a ring.
Z is a single bond or a divalent linking group. ]

Examples of the substituent in R ^{e1 to} R ^e13 include a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group, a cyano group, a nitro group, a carboxyl group, an alkoxy group, and aryl. Oxy group, silyloxy group, heterocyclic oxy group, acyloxy group, carbamoyloxy group, alkoxycarbonyloxy group, aryloxycarbonyloxy group, amino group, ammonio group, acylamino group, aminocarbonylamino group, alkoxycarbonylamino group, aryloxy Carbonylamino group, sulfamoylamino group, alkyl and arylsulfonylamino group, mercapto group, alkylthio group, arylthio group, heterocyclic thio group, sulfamoyl group, sulfo group, alkyl and arylsulfinyl group Alkyl and arylsulfonyl groups, acyl groups, aryloxycarbonyl groups, alkoxycarbonyl groups, carbamoyl groups, aryl and heterocyclic azo groups, imide groups, phosphino groups, phosphinyl groups, phosphinyloxy groups, phosphinylamino groups, phosphono groups Group, silyl group, hydrazino group, ureido group, boronic acid group, phosphato group, sulfato group and the like.

Examples of the ring formed by combining two adjacent R ^{e1 to} R ^e13 include an aromatic or non-aromatic hydrocarbon ring or a heterocyclic ring. These can be further combined to form a polycyclic fused ring.
Specifically, benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, fluorene ring, triphenylene ring, naphthacene ring, biphenyl ring, pyrrole ring, furan ring, thiophene ring, imidazole ring, oxazole ring, thiazole ring, pyridine ring, Pyrazine ring, pyrimidine ring, pyridazine ring, indolizine ring, indole ring, indole ring, benzofuran ring, benzothiophene ring, isobenzofuran ring, quinolidine ring, quinoline ring, phthalazine ring, naphthyridine ring, quinoxaline ring, quinoxazoline ring, isoquinoline ring, carbazole ring Phenanthridine ring, acridine ring, phenanthroline ring, thianthrene ring, chromene ring, xanthene ring, phenoxathiin ring, phenothiazine ring, phenazine ring and the like.

R ^{e1 to} R ^e13 are preferably a hydrogen atom or a halogen atom, a hydroxyl group, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a cyano group, a carboxyl group, an alkoxy group, an aryloxy group, an acyloxy group, or a carbamoyloxy group. , Acylamino group, aminocarbonylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, sulfamoylamino group, alkyl and arylsulfonylamino group, alkylthio group, arylthio group, sulfamoyl group, alkyl and arylsulfonyl group, aryloxy A carbonyl group, an alkoxycarbonyl group, a carbamoyl group, an imide group, a silyl group, and a ureido group.

More preferably, a hydrogen atom or a halogen atom, a hydroxyl group, an alkyl group, a cyano group, an alkoxy group, an acyloxy group, an acylamino group, an aminocarbonylamino group, an alkoxycarbonylamino group, an alkyl and arylsulfonylamino group, an alkylthio group, a sulfamoyl group, An alkyl and arylsulfonyl group, an alkoxycarbonyl group, and a carbamoyl group;
Particularly preferred are a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group or an alkoxy group.
That is, it is preferable that R ^{e1 to} R ^{e13 do not} include a vinyl group, an acryloyl group, a methacryloyl group, an acryloyloxy group, or a methacryloyloxy group.

Examples of the divalent linking group include an alkylene group, an arylene group, a carbonyl group, a sulfonyl group, a carbonyloxy group, a carbonylamino group, a sulfonylamide group, an ether group, a thioether group, an amino group, a disulfide group, an acyl group, and an alkyl group. Examples include a sulfonyl group, —CH═CH—, —C≡C—, an aminocarbonylamino group, an aminosulfonylamino group, an oxygen atom, a sulfur atom, and —SO ₂ —. These may further have a substituent. This substituent can be selected from those exemplified as R ^{e1 to} R ^e13 .

Z is preferably a single bond, an alkylene group, an arylene group, an ether group, a thioether group, an amino group, —CH═CH—, —C≡C—, an aminocarbonylamino group, an aminosulfonylamino group, an oxygen atom, sulfur atom and -SO ₂ - and the like. These may further have a substituent. This substituent can be selected from those exemplified as R ^{a1 to} R ^a13 .
More preferably, a single bond, an ether group, a thioether group, an oxygen atom, a sulfur atom and -SO 2 _- and the like.
Particularly preferred is a single bond.

As a cation represented by a formula (EE), the following are mentioned, for example.
(In the formula, R ^e1 , R ^e5 and R ^e9 represent the same meaning as described above,
t represents an integer of 0 to 3. )

Specific examples of the cation represented by the formula (EE) include the following cations.

The anion and the cation can be arbitrarily combined.
For example, the salt represented by the formula (I) includes a compound represented by any one of the formulas (I-1) to (I-8). When such a compound is used as an acid generator, a resist composition showing good resolution can be provided.

The salt represented by the formula (I) can be formed by the following production method. In addition, in the formula shown with the manufacturing method of the following acid generators, unless otherwise specified, the definition of each substituent shows the same meaning as described above.

  For example, the salt represented by the formula (1) and the onium salt represented by the formula (3) are mixed in an inert solvent such as acetonitrile, water, methanol, chloroform, methylene chloride, or an aprotic solvent. Thus, it can be produced by a method of stirring and reacting in a temperature range of about 0 to 150 ° C., preferably about 0 to 100 ° C. Here, examples of the aprotic solvent include dichloroethane, toluene, ethylbenzene, monochlorobenzene, acetonitrile, N, N-dimethylformamide and the like.

[Wherein M ⁺ represents Li ⁺ , Na ⁺ , K ⁺ or Ag ⁺ .
Z ¹⁻ represents F ⁻ , Cl ⁻ , Br ⁻ , I ⁻ , BF ₄ ⁻ , AsF ₆ ⁻ , SbF ₆ ⁻ , PF ₆ ⁻ or ClO ₄ ⁻ . ]

  The usage-amount of the onium salt of Formula (3) is about 0.5-2 mol normally with respect to 1 mol of salts represented by Formula (1). The salt may be taken out by recrystallization or may be purified by washing with water.

  Among the salts represented by the formula (1), the salt having an anion represented by the formula (IA) is, for example, first represented by the alcohol represented by the formula (4) and the formula (5). It can be obtained by esterification reaction with carboxylic acid.

  The amount of the carboxylic acid represented by the formula (5) in the esterification reaction is usually about 0.2 to 3 mol, preferably 0.5 to 1 mol of the alcohol represented by the formula (4). About 2 moles. The amount of the acid catalyst used in the esterification reaction may be a catalytic amount or an amount corresponding to a solvent, and is usually about 0.001 to 5 mol.

Moreover, among the salts represented by the formula (1), the salt having an anion represented by the formula (IA) includes, for example, an alcohol represented by the formula (6) and a carboxyl represented by the formula (7). It can also be produced by esterifying the acid and then hydrolyzing with MOH.

  Examples of the alkali metal hydroxide represented by MOH include lithium hydroxide, sodium hydroxide and potassium hydroxide, preferably lithium hydroxide and sodium hydroxide.

The esterification reaction is usually carried out by stirring in an aprotic solvent similar to the above in a temperature range of about 20 to 200 ° C, preferably in a temperature range of about 50 to 150 ° C.
In the esterification reaction, an organic acid such as p-toluenesulfonic acid and / or an inorganic acid such as sulfuric acid may be usually added as an acid catalyst.
Furthermore, a dehydrating agent may be added in the esterification reaction.
Examples of the dehydrating agent include dicyclohexylcarbodiimide, 1-alkyl-2-halopyridinium salt, 1,1-carbonyldiimidazole, bis (2-oxo-3-oxazolidinyl) phosphine acid chloride, 1-ethyl-3- (3 -Dimethylaminopropyl) carbodiimide hydrochloride, di-2-pyridyl carbonate, di-2-pyridylthiono carbonate, 6-methyl-2-nitrobenzoic anhydride in the presence of 4- (dimethylamino) pyridine, and the like. The esterification reaction using an acid catalyst is preferably carried out while dehydrating using a Dean Stark apparatus or the like because the reaction time tends to be shortened.

  The method for producing a salt having an anion represented by formula (IA) can be similarly applied to the production of a salt having an anion represented by formula (IB).

  Furthermore, among the salts represented by the formula (1), the salt having an anion represented by the formula (IC) is, for example, first represented by the carboxylic acid represented by the formula (8) and the formula (9). It can be obtained by esterification reaction with the alcohol to be produced.

  The amount of the alcohol represented by the formula (9) in the esterification reaction is about 0.5 to 3 mol, preferably about 1 to 2 mol with respect to 1 mol of the carboxylic acid represented by the formula (8). It is. The acid catalyst in the esterification reaction may be a catalytic amount or an amount corresponding to a solvent with respect to 1 mol of the carboxylic acid represented by the formula (8), and is usually about 0.001 to 5 mol. The dehydrating agent in the esterification reaction is about 0.5 to 5 mol, preferably about 1 to 3 mol, per 1 mol of the carboxylic acid represented by the formula (8).

  In the esterification reaction of the carboxylic acid represented by the formula (8) and the alcohol represented by the formula (9), the carboxylic acid represented by the formula (8) is converted into the corresponding acid halide, and the formula (9 It can also be performed by reacting with an alcohol represented by

Examples of the reagent that converts to an acid halide include thionyl chloride, thionyl bromide, phosphorus trichloride, phosphorus pentachloride, and phosphorus tribromide. Examples of the solvent used in the acid halide reaction include the same aprotic solvents as described above. The reaction may be carried out with stirring in a temperature range of about 20 to 200 ° C., preferably in a temperature range of about 50 to 150 ° C.
In the above reaction, an amine compound can be added as a catalyst.

By reacting the obtained acid halide with an alcohol represented by the formula (9) in an inert solvent (for example, an aprotic solvent), a salt having an anion represented by the formula (IC) is obtained. be able to. The reaction is preferably performed in a temperature range of about 20 to 200 ° C, and more preferably in a temperature range of about 50 to 150 ° C. It is also suitable to use a deoxidizer.
Examples of the deoxidizer include organic bases such as triethylamine and pyridine, and inorganic bases such as sodium hydroxide, potassium carbonate, and sodium hydride.
The amount of the base used may be an amount corresponding to the solvent with respect to 1 mol of the acid halide, and is usually about 0.001 to 5 mol, preferably about 1 to 3 mol.

As a method for producing a salt having an anion represented by (IC), an esterification reaction between a carboxylic acid represented by formula (10) and an alcohol represented by formula (11) is carried out, and the salt is represented by MOH. There is also a method of obtaining a salt by hydrolysis with an alkali metal hydroxide. M ⁺ represents the same meaning as described above.

The esterification reaction of the carboxylic acid represented by the formula (10) and the alcohol represented by the formula (11) is usually performed in a temperature range of about 20 to 200 ° C. in the same aprotic solvent as described above. Preferably, stirring may be performed in a temperature range of about 50 to 150 ° C.
In the esterification reaction, the same acid catalyst as described above is usually added.
Furthermore, in this esterification reaction, a dehydrating agent may be added as described above.

  Examples of the method for producing a salt having an anion represented by the formula (ID) include a method of first dehydrating and condensing the alcohol represented by the formula (12) and the alcohol represented by the formula (13). It is done.

  Moreover, as a manufacturing method of the salt which has an anion represented by Formula (ID), after making the alcohol represented by Formula (14) and the alcohol represented by Formula (15) react, it represents with MOH. There is also a method of dehydrating and condensing with an alkali metal hydroxide.

The reaction of the alcohol represented by the formula (14) and the alcohol represented by the formula (15) is usually in a temperature range of about 20 to 200 ° C., preferably 50 to 150 ° C. in an aprotic solvent. What is necessary is just to stir in the temperature range of about.
In the reaction, an acid catalyst is usually used.
Further, in the reaction, the above-described dehydrating agent may be added.
The reaction using an acid catalyst is preferably carried out while dehydrating using a Dean Stark apparatus or the like because the reaction time tends to be shortened.

  The amount of the alcohol represented by the formula (14) in the reaction is about 0.5 to 3 mol, preferably about 1 to 2 mol per 1 mol of the alcohol represented by the formula (15). . The acid catalyst in the etherification reaction may be a catalytic amount or an amount corresponding to a solvent with respect to 1 mol of the alcohol represented by the formula (15), and is usually about 0.001 to 5 mol. The dehydrating agent in the etherification reaction is about 0.5 to 5 mol, preferably about 1 to 3 mol per 1 mol of the alcohol represented by the formula (15).

  The reaction between the alcohol represented by the formula (16) and the alcohol represented by the formula (17) is obtained by converting the alcohol represented by the formula (17) into a compound represented by the formula (18). It can also be carried out by reacting the compound represented by the formula (18) with the alcohol represented by the formula (16).

[Wherein L represents chlorine, bromine, iodine, mesyloxy group, tosyloxy group or trifluoromethanesulfonyloxy group. ]

In order to convert the alcohol represented by the formula (17) into the compound represented by the formula (18), for example, thionyl chloride, thionyl bromide, phosphorus trichloride, phosphorus pentachloride, phosphorus tribromide, mesyl chloride, Tosyl chloride, trifluoromethanesulfonic anhydride and the like are reacted with the alcohol represented by the formula (17).
Said reaction is performed in the inert solvent mentioned above. The reaction is carried out with stirring in a temperature range of about -70 to 200 ° C, preferably in a temperature range of about -50 to 150 ° C. It is also suitable to use a deoxidizer as described above.
The amount of the base used may be an amount corresponding to a solvent with respect to 1 mol of the alcohol represented by the formula (17), and is usually about 0.001 to 5 mol, preferably about 1 to 3 mol.

A salt having an anion represented by the formula (ID) can be obtained by reacting the obtained compound represented by the formula (18) with an alcohol represented by the formula (16) in an inert solvent. it can. The reaction is carried out in a temperature range of about 20 to 200 ° C, preferably in a temperature range of about 50 to 150 ° C.
In the reaction, it is suitable to use a deoxidizing agent.
When using a deoxidizing agent, the amount thereof may be an amount corresponding to a solvent with respect to 1 mol of the compound represented by the formula (18), and is usually about 0.001 to 5 mol, preferably 1 to 3 mol. It is about a mole.

In addition, the manufacturing method of the cation in the acid generator represented by the formula (I) can be manufactured using any method known in the art. For example, the manufacturing method represented by the following reaction formula is mentioned.
[Wherein R ^{e1 to} R ^e13 and Z represent the same meaning as described above. ]

Examples of the compound represented by the formula (EE-A) include dibenzothiophene sulfone.
Examples of the compound represented by the formula (EE-B) include benzene and toluene.

  The compound represented by the formula (EE-A) and the compound represented by the formula (EE-B) are reacted in the presence of an acid and a condensing agent, and then reacted with an alkali metal halide. A compound represented by EE-C) is obtained.

Examples of the acid include methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, toluenesulfonic acid and the like.
Examples of the condensing agent include diphosphorus pentoxide and methanesulfonic anhydride.
Examples of the alkali metal halide include potassium iodide.

  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.

The resist composition of the present invention contains an acid generator containing a salt represented by the formula (I) and a resin. The resin here is a resin having an acid labile group and insoluble or hardly soluble in an alkaline aqueous solution, and this resin that has reacted with an acid is a resin that can be dissolved in an alkaline aqueous solution.
In this resist composition, an acid is generated from the salt represented by the formula (I) by exposure. The acid catalyzes and cleaves the acid labile group in the resin, making the resin soluble in an aqueous alkaline solution. Such a resist composition is suitable as a chemically amplified resist composition, particularly as a positive resist composition.
However, in the resist composition of the present invention, a known salt other than the salt represented by the formula (I) may be used in combination as the acid generator.

Examples of the acid labile group include a group having an alkyl ester in which the carbon atom adjacent to the oxygen atom is a quaternary carbon atom, a group having a carboxylic acid ester such as an alicyclic ester, and a carbon atom adjacent to the oxygen atom. And a group having a lactone ring which is a quaternary carbon atom.
Here, the quaternary carbon atom means a carbon atom bonded to a substituent other than a hydrogen atom and not bonded to hydrogen, and an acid-labile group includes an oxygen atom of —COO—. The bonded carbon atom is preferably a quaternary carbon atom bonded to three carbon atoms.

When a group having a carboxylic acid ester which is one of acid labile groups is exemplified as an R ester of -COOR (-COO-C (CH ₃ ) ₃ is referred to as tert-butyl ester),
an alkyl ester in which the carbon atom adjacent to the oxygen atom represented by tert-butyl ester is a quaternary carbon atom;
Methoxymethyl ester, ethoxymethyl ester, 1-ethoxyethyl ester, 1-isobutoxyethyl ester, 1-isopropoxyethyl ester, 1-ethoxypropyl ester, 1- (2-methoxyethoxy) ethyl ester, 1- (2- Acetoxyethoxy) ethyl ester, 1- [2- (1-adamantyloxy) ethoxy] ethyl ester, 1- [2- (1-adamantanecarbonyloxy) ethoxy] ethyl ester, tetrahydro-2-furyl ester and tetrahydro-2- Acetal-type esters such as pyranyl esters;
The carbon atom adjacent to the oxygen atom such as isobornyl ester, 1-alkyl cycloalkyl ester, 2-alkyl-2-adamantyl ester, 1- (1-adamantyl) -1-alkylalkyl ester is a quaternary carbon atom. Examples include alicyclic esters.

  Examples of the group having a carboxylic acid ester include a group having a (meth) acrylic acid ester, a norbornene carboxylic acid ester, a tricyclodecene carboxylic acid ester, and a tetracyclodecene carboxylic acid ester.

The resin in the resist composition of the present invention can be produced by addition polymerization of a monomer having an acid labile group and an olefinic double bond.
Such monomers include bulky groups such as alicyclic structures such as 2-alkyl-2-adamantyl groups and 1- (1-adamantyl) -1-alkylalkyl groups as acid labile groups. Monomers are preferred because the resolution of the resulting resist tends to be excellent.

  Specific examples of the monomer containing a bulky group include 2-alkyl-2-adamantyl (meth) acrylate, 1- (1-adamantyl) -1-alkylalkyl (meth) acrylate, and 5-norbornene-2. -2-alkyl-2-adamantyl carboxylate, 1- (1-adamantyl) -1-alkylalkyl 5-norbornene-2-carboxylate, 2-alkyl-2-adamantyl α-chloroacrylate, α-chloroacrylic acid 1- (1-adamantyl) -1-alkylalkyl and the like.

  In particular, when 2-alkyl-2-adamantyl (meth) acrylate or 2-alkyl-2-adamantyl α-chloroacrylate is used as a monomer, it is preferable because the resolution of the resulting resist tends to be excellent.

  Specifically, as 2-alkyl-2-adamantyl (meth) acrylate, for example, 2-methyl-2-adamantyl acrylate, 2-methyl-2-adamantyl methacrylate, 2-ethyl-2-acrylate Examples thereof include adamantyl, 2-ethyl-2-adamantyl methacrylate, 2-n-butyl-2-adamantyl acrylate, and the like. Examples of α-chloroacrylic acid 2-alkyl-2-adamantyl include α-chloroacrylic acid. Examples include 2-methyl-2-adamantyl and 2-ethyl-2-adamantyl α-chloroacrylate.

  Among these, when 2-ethyl-2-adamantyl (meth) acrylate or 2-isopropyl-2-adamantyl (meth) acrylate is used, the resulting resist tends to have excellent sensitivity and heat resistance. preferable.

  (Meth) acrylic acid 2-alkyl-2-adamantyl can be usually produced by a reaction of 2-alkyl-2-adamantanol or a metal salt thereof with acrylic acid halide or methacrylic acid halide.

The resin used in the present invention may contain a structural unit derived from an acid-stable monomer in addition to a structural unit derived from a monomer having an acid-labile group. Here, the structure derived from an acid-stable monomer means a structure that is not cleaved by the salt (I) of the present invention.
Specifically, a structural unit derived from a monomer having a free carboxylic acid group such as acrylic acid or methacrylic acid, or a structural unit derived from an aliphatic unsaturated dicarboxylic anhydride such as maleic anhydride or itaconic anhydride , A structural unit derived from 2-norbornene, a structural unit derived from (meth) acrylonitrile, a carbon atom adjacent to the oxygen atom is a secondary carbon atom or an alkyl ester or 1-adamantyl ester of a tertiary carbon atom (meth) Structural units derived from acrylates, structural units derived from styrene monomers such as p- or m-hydroxystyrene, derived from (meth) acryloyloxy-γ-butyrolactone in which the lactone ring may be substituted with an alkyl group And a structural unit. In the 1-adamantyl ester, the carbon atom adjacent to the oxygen atom is a quaternary carbon atom. However, the 1-adamantyl ester is an acid-stable group, and the 1-adamantyl ester may be bonded with a hydroxyl group.

  Specific examples of acid-stable monomers include 3-hydroxy-1-adamantyl (meth) acrylate, 3,5-dihydroxy-1-adamantyl (meth) acrylate, α- (meth) acryloyloxy-γ-butyrolactone, β- (meth) acryloyloxy-γ-butyrolactone, a monomer deriving the structural unit represented by the formula (a), a monomer deriving the structural unit represented by the formula (b), hydroxystyrene, norbornene, etc. Examples thereof include an alicyclic compound having a bond, an aliphatic unsaturated dicarboxylic acid anhydride such as maleic anhydride, and itaconic anhydride.

  Among these, in particular, structural units derived from styrene monomers such as p- or m-hydroxystyrene, structural units derived from 3-hydroxy-1-adamantyl (meth) acrylate, (meth) acrylic acid 3,5 A resist obtained from a resin containing any one of a structural unit derived from -dihydroxy-1-adamantyl, a structural unit represented by formula (a), and a structural unit represented by formula (b) has the following characteristics: This is preferable because the resolution of the image tends to be improved.

(In the formula, R ¹ and R ² each independently represent a hydrogen atom or a methyl group; R ³ and R ⁴ each independently represent a hydrogen atom, a methyl group, a trifluoromethyl group, or a halogen atom; And j represents an integer of 1 to 3. When i is 2 or 3, R ³ may be a different group, and when j is 2 or 3, R ⁴ may be a different group. Good.)

  Monomers such as (meth) acrylic acid 3-hydroxy-1-adamantyl and (meth) acrylic acid 3,5-dihydroxy-1-adamantyl are commercially available. For example, the corresponding hydroxyadamantane is converted to (meth) acrylic acid or It can also be produced by reacting with the halide.

  In addition, a monomer such as (meth) acryloyloxy-γ-butyrolactone is obtained by reacting α- or β-bromo-γ-butyrolactone, in which the lactone ring may be substituted with an alkyl group, with acrylic acid or methacrylic acid, or lactone It can be produced by reacting an α- or β-hydroxy-γ-butyrolactone whose ring may be substituted with an alkyl group with an acrylic acid halide or a methacrylic acid halide.

  Examples of the monomer that gives the structural unit represented by formula (a) or formula (b) include (meth) acrylic acid esters of alicyclic lactones having the following hydroxyl groups, and mixtures thereof. These esters can be produced, for example, by a reaction between a corresponding alicyclic lactone having a hydroxyl group and (meth) acrylic acid (see, for example, JP-A No. 2000-26446).

  Here, as (meth) acryloyloxy-γ-butyrolactone, for example, α-acryloyloxy-γ-butyrolactone, α-methacryloyloxy-γ-butyrolactone, α-acryloyloxy-β, β-dimethyl-γ-butyrolactone, α- Methacryloyloxy-β, β-dimethyl-γ-butyrolactone, α-acryloyloxy-α-methyl-γ-butyrolactone, α-methacryloyloxy-α-methyl-γ-butyrolactone, β-acryloyloxy-γ-butyrolactone, β- Examples include methacryloyloxy-γ-butyrolactone, β-methacryloyloxy-α-methyl-γ-butyrolactone, and the like.

In the case of KrF excimer laser exposure and EUV exposure, sufficient transmittance can be obtained even when a structural unit derived from a styrene monomer such as p- or m-hydroxystyrene is used as the structural unit of the resin. Such a copolymer resin can be obtained by radical polymerization of the corresponding (meth) acrylic acid ester monomer, acetoxystyrene and styrene, and then deacetylation with an acid.
Examples of the monomer that derives the structural unit derived from the styrene monomer include the following compounds.

  Of the above monomers, 4-hydroxystyrene or 4-hydroxy-α-methylstyrene is particularly preferred.

  Moreover, since the resin containing a structural unit derived from 2-norbornene has an alicyclic skeleton directly in the main chain, it has a sturdy structure and exhibits excellent dry etching resistance. The structural unit derived from 2-norbornene can be introduced into the main chain by radical polymerization using, in addition to the corresponding 2-norbornene, an aliphatic unsaturated dicarboxylic anhydride such as maleic anhydride or itaconic anhydride. Therefore, the one formed by opening the double bond of the norbornene structure can be represented by the formula (c), and the one formed by opening the double bond of maleic anhydride and itaconic anhydride is respectively It can represent with Formula (d) and Formula (e).

Here, R ⁵ and R ⁶ in formula (c) are each independently a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, a carboxyl group, a cyano group, or —COOU (U is an alcohol residue). Or R ⁵ and R ⁶ are bonded to each other to represent a carboxylic anhydride residue represented by —C (═O) OC (═O) —.
When R ⁵ and R ⁶ are a group —COOU, the carboxyl group is an ester group, and the alcohol residue corresponding to U has, for example, about 1 to 8 carbon atoms that may be substituted. And an alkyl group, a 2-oxooxolan-3- or -4-yl group. Here, in the alkyl group, a hydroxyl group, an alicyclic hydrocarbon residue, or the like may be bonded as a substituent.
Specific examples when R ⁵ and R ⁶ are alkyl groups include a methyl group, an ethyl group, and a propyl group. Specific examples of the alkyl group to which a hydroxyl group is bonded include a hydroxymethyl group and 2-hydroxyethyl group. Group and the like.

As described above, specific examples of the norbornene structure represented by the formula (c), which is a monomer that gives a stable structural unit to an acid, include the following compounds.
2-norbornene,
2-hydroxy-5-norbornene,
5-norbornene-2-carboxylic acid,
Methyl 5-norbornene-2-carboxylate,
2-hydroxy-1-ethyl 5-norbornene-2-carboxylate,
5-norbornene-2-methanol,
5-norbornene-2,3-dicarboxylic anhydride.

In addition, if U of R ⁵ and R ⁶ —COOU in the formula (c) is an acid labile group such as an alicyclic ester in which the carbon atom adjacent to the oxygen atom is a quaternary carbon atom, Although it has a norbornene structure, it is a structural unit having an acid labile group. Examples of the monomer containing a norbornene structure and an acid labile group include, for example, 5-norbornene-2-carboxylic acid-t-butyl, 5-norbornene-2-carboxylic acid 1-cyclohexyl-1-methylethyl, and 5-norbornene. 2-carboxylate 1-methylcyclohexyl, 5-norbornene-2-carboxylic acid 2-methyl-2-adamantyl, 5-norbornene-2-carboxylic acid 2-ethyl-2-adamantyl, 5-norbornene-2-carboxylic acid 1- (4-methylcyclohexyl) -1-methylethyl, 5-norbornene-2-carboxylic acid 1- (4-hydroxycyclohexyl) -1-methylethyl, 5-norbornene-2-carboxylic acid 1-methyl-1- (4-Oxocyclohexyl) ethyl, 5-norbornene-2-carboxylic acid 1- (1-adama) Chill) -1-methylethyl and the like.

Further, the acid-stable group may contain a structural unit represented by the formula (b1) and a structural unit containing a fluorine atom.

[In the formula (b1),
R ^{b ′} represents a hydrogen atom, a methyl group or a trifluoromethyl group.
AR represents a linear, branched or cyclic hydrocarbon group having 1 to 30 carbon atoms, and at least one hydrogen atom contained in the hydrocarbon group is substituted with a fluorine atom. The methylene group contained in the hydrocarbon group may be replaced with an oxygen atom, a sulfur atom, or —N (R ^c ) —, and the hydrogen atom contained in the hydrocarbon group is a hydroxyl group, a straight chain or a branched chain. Which may be substituted with an aliphatic hydrocarbon group having 1 to 6 carbon atoms. ]

Specific examples of the monomer for deriving the structural unit represented by the formula (b1) include the following monomers.

  The resin used in the resist composition of the present invention varies depending on the type of radiation used for patterning exposure and the type of acid labile group, but is usually derived from a monomer having an acid labile group in the resin. The content of the structural unit is adjusted to a range of 10 to 80 mol%.

  And as a structural unit derived from a monomer having an acid-labile group, in particular, 2-alkyl-2-adamantyl (meth) acrylate, 1- (1-adamantyl) -1-alkylalkyl (meth) acrylate In the case where the structural unit is 15 mol% or more of the total structural units constituting the resin, the resin has an alicyclic group, so that the resin has a strong structure and gives dry resist resistance to resist. This is advantageous.

  In addition, when using an alicyclic compound having an olefinic double bond in the molecule and an aliphatic unsaturated dicarboxylic acid anhydride as monomers, these tend to be difficult to undergo addition polymerization. These are preferably used in excess.

  Further, as the monomer used, monomers having the same olefinic double bond but different acid labile groups may be used in combination, or monomers having the same acid labile group but different olefinic double bonds may be used. You may use together, and you may use together the monomer from which the combination of an acid labile group and an olefinic double bond differs.

Examples of the known acid generator include salts obtained by arbitrarily combining the anion of the salt represented by the formula (I) and the cation shown below.
Examples of the cation include cations such as formula (IXz), formula (IXb), formula (IXc), and formula (IXd).

[In the formula (IXz),
P ^a , P ^b and P ^c are each independently a linear or branched alkyl group having 1 to 30 carbon atoms, an optionally substituted alicyclic hydrocarbon group having 3 to 30 carbon atoms, or a substituted group. Represents an optionally substituted aromatic hydrocarbon group having 6 to 20 carbon atoms. When any one of P ^a , P ^b and P ^c is an alkyl group, the alkyl group is a hydroxyl group, a linear or branched alkoxy group having 1 to 12 carbon atoms, or a cyclic carbonization having 3 to 12 carbon atoms. It may be substituted with a hydrogen group, and when any of P ^a , P ^b and P ^c is an alicyclic hydrocarbon group, a hydroxyl group, a linear or branched alkyl having 1 to 12 carbon atoms Group or an alkoxy group having 1 to 12 carbon atoms.
In formula (IXb),
P ⁴ and P ⁵ each independently represent a hydrogen atom, a hydroxyl group, a linear or branched alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.
In formula (IXc),
P ⁶ and P ⁷ each independently represent a linear or branched alkyl group having 1 to 12 carbon atoms or a cycloalkyl group having 3 to 12 carbon atoms, or P ⁶ and P ⁷ are combined together. A ring having 3 to 12 carbon atoms may be formed.
P ⁸ represents a hydrogen atom, and P ⁹ is a linear or branched alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, or an optionally substituted carbon atom having 6 to 20 carbon atoms. Or a ring having 3 to 12 carbon atoms may be formed by combining P ⁸ and P ⁹ together.
In formula (IXd),
P ¹⁰ to P ²¹ are independently of each other, represent a hydrogen atom, a hydroxyl group, an alkyl group or an alkoxy group having 1 to 12 carbon atoms having 1 to 12 carbon atoms. E represents a sulfur atom or an oxygen atom.
m represents 0 or 1. ]

  Among the cations represented by the formula (IXz), for example, the cation represented by the formula (IXa) is preferable.

[In the formula (IXa)
P ^{1 to} P ³ are each independently a hydrogen atom, a hydroxyl group, a halogen atom, a linear or branched alkyl group having 1 to 12 carbon atoms, or a linear or branched alkoxy group having 1 to 12 carbon atoms. Alternatively, it represents an alicyclic hydrocarbon having 4 to 36 carbon atoms, and the hydrogen atom contained in the alicyclic hydrocarbon group is a halogen atom, a hydroxyl group, a linear or branched alkyl group having 1 to 12 carbon atoms, It is substituted with a linear or branched alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, a glycidoxy group, or an acyl group having 2 to 4 carbon atoms. Also good. ]

  Examples of the cyclic hydrocarbon group include those containing an adamantyl skeleton and an isobornyl skeleton. Preferred examples include 2-alkyl-2-adamantyl group, 1- (1-adamantyl) -1-alkyl group and isobornyl group.

Specific examples of the cation represented by the formula (IXa) include the followings.

  Among the cations represented by the formula (IXa), the cation represented by the formula (IXe) is preferably used because of its easy production.

[In the formula (IXe)
P ²² , P ²³ and P ²⁴ are each independently a hydrogen atom, a hydroxyl group, a halogen atom, a linear or branched alkyl group having 1 to 12 carbon atoms, or a linear or branched carbon number 1 to 12. Represents an alkoxy group. ]

  Specific examples of the cation represented by the formula (IXb) include the followings.

  Specific examples of the cation represented by the formula (IXc) include the followings.

  Specific examples of the cation represented by the formula (IXd) include the followings.

  When used as a chemically amplified photoresist composition, the resist composition of the present invention contains a basic compound, preferably a basic nitrogen-containing organic compound, particularly preferably an amine or ammonium salt. By adding a basic compound as a quencher, it is possible to improve the performance degradation due to the deactivation of the acid accompanying the holding after exposure. Specific examples of the basic compound used for the quencher include those represented by the following formulas.

In the formula, R ¹¹ , R ¹² and R ¹⁷ each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group or an aryl group. The alkyl group preferably has about 1 to 6 carbon atoms, the cycloalkyl group preferably has about 5 to 10 carbon atoms, and the aryl group preferably has about 6 to 10 carbon atoms. Of carbon atoms. Further, at least one hydrogen atom on the alkyl group, cycloalkyl group or aryl group may be independently substituted with a hydroxyl group, an amino group, or an alkoxy group having 1 to 6 carbon atoms. Good. At least one hydrogen atom on the amino group may be independently substituted with an alkyl group having 1 to 4 carbon atoms.

R ¹³ and R ¹⁴ each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group or an alkoxy group. The alkyl group preferably has about 1 to 6 carbon atoms, the cycloalkyl group preferably has about 5 to 10 carbon atoms, and the aryl group preferably has 6 to 10 carbon atoms. The alkoxy group preferably has 1 to 6 carbon atoms. Alternatively, R ¹³ and R ¹⁴ may be bonded to form an aromatic ring.
Further, at least one hydrogen atom on the alkyl group, cycloalkyl group, aryl group, or alkoxy group is independently a hydroxyl group, an amino group, or an alkoxy group having about 1 to 6 carbon atoms. May be substituted. At least one of the hydrogen atoms on the amino group may be substituted with an alkyl group having 1 to 4 carbon atoms.

R ¹⁵ each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group or a nitro group. The alkyl group preferably has about 1 to 6 carbon atoms, the cycloalkyl group preferably has about 5 to 10 carbon atoms, and the aryl group preferably has 6 to 10 carbon atoms. The alkoxy group preferably has 1 to 6 carbon atoms.
Further, at least one hydrogen atom on the alkyl group, cycloalkyl group, aryl group, or alkoxy group is independently a hydroxyl group, an amino group, or an alkoxy group having about 1 to 6 carbon atoms. May be substituted. At least one of the hydrogen atoms on the amino group may be substituted with an alkyl group having 1 to 4 carbon atoms.

R ¹⁶ represents an alkyl group or a cycloalkyl group. The alkyl group preferably has about 1 to 6 carbon atoms, and the cycloalkyl group preferably has about 5 to 10 carbon atoms. Furthermore, at least one hydrogen atom on the alkyl group or cycloalkyl group may be independently substituted with a hydroxyl group, an amino group, or an alkoxy group having 1 to 6 carbon atoms. At least one of the hydrogen atoms on the amino group may be substituted with an alkyl group having 1 to 4 carbon atoms.

R ¹⁸ , R ¹⁹ and R ²⁰ each independently represents an alkyl group, a cycloalkyl group or an aryl group. The alkyl group preferably has about 1 to 6 carbon atoms, the cycloalkyl group preferably has about 5 to 10 carbon atoms, and the aryl group preferably has 6 to 10 carbon atoms. Has about carbon atoms. Furthermore, at least one hydrogen atom on the alkyl group, cycloalkyl group or aryl group may be independently substituted with a hydroxyl group, an amino group, or an alkoxy group having 1 to 6 carbon atoms. . At least one of the hydrogen atoms on the amino group may be substituted with an alkyl group having 1 to 4 carbon atoms.

W represents an alkylene group, a carbonyl group, an imino group, a sulfide group or a disulfide group. The alkylene group preferably has about 2 to 6 carbon atoms.
Further, in R ^{11 to} R ²⁰ , any of those that can take both a linear structure and a branched structure may be used.

  Specific examples of such compounds include hexylamine, heptylamine, octylamine, nonylamine, decylamine, aniline, 2-, 3- or 4-methylaniline, 4-nitroaniline, 1- or 2-naphthylamine, and ethylenediamine. , Tetramethylenediamine, hexamethylenediamine, 4,4′-diamino-1,2-diphenylethane, 4,4′-diamino-3,3′-dimethyldiphenylmethane, 4,4′-diamino-3,3′- Diethyldiphenylmethane, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, N-methylaniline, piperidine, diphenylamine, triethylamine, trimethylamine, tripropylamine, tributylamine , Tripentylamine, trihexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, methyldibutylamine, methyldipentylamine, methyldihexylamine, methyldicyclohexylamine, methyldiheptylamine, methyldioctylamine Methyldinonylamine, methyldidecylamine, ethyldibutylamine, ethyldipentylamine, ethyldihexylamine, ethyldiheptylamine, ethyldioctylamine, ethyldinonylamine, ethyldidecylamine, dicyclohexylmethylamine, tris [2- (2-methoxyethoxy) ethyl] amine, triisopropanolamine, N, N-dimethylaniline, 2,6-diisopropylaniline, imidazole, pyridine 4-methylpyridine, 4-methylimidazole, bipyridine, 2,2'-dipyridylamine, di-2-pyridyl ketone, 1,2-di (2-pyridyl) ethane, 1,2-di (4-pyridyl) ethane 1,3-di (4-pyridyl) propane, 1,2-bis (2-pyridyl) ethylene, 1,2-bis (4-pyridyl) ethylene, 1,2-bis (4-pyridyloxy) ethane, 4,4′-dipyridyl sulfide, 4,4′-dipyridyl disulfide, 1,2-bis (4-pyridyl) ethylene, 2,2′-dipicolylamine, 3,3′-dipicolylamine, tetramethylammonium hydroxy , Tetraisopropylammonium hydroxide, tetrabutylammonium hydroxide, tetra-n-hexylammonium hydroxide, tetra-n -Octylammonium hydroxide, phenyltrimethylammonium hydroxide, 3-trifluoromethylphenyltrimethylammonium hydroxide, (2-hydroxyethyl) trimethylammonium hydroxide (common name: choline), and the like can be given.

  Furthermore, a hindered amine compound having a piperidine skeleton as disclosed in JP-A-11-52575 can be used as a quencher.

The resist composition of the present invention preferably contains the resin in the range of about 80 to 99.9% by weight and the acid generator in the range of about 0.1 to 20% by weight based on the total solid content.
In addition, when a basic compound that is a quencher is used as the chemically amplified resist composition, the basic compound is contained in a range of about 0.01 to 1% by weight based on the total solid content of the resist composition. Is preferred.
The resist composition can further contain small amounts of various additives such as sensitizers, dissolution inhibitors, other resins, surfactants, stabilizers, and dyes as necessary.

  The resist composition of the present invention is usually used as a resist solution composition in a state in which each of the above components is dissolved in a solvent, and is usually used in industrial processes such as spin coating on a substrate such as a silicon wafer. Applied by. The solvent used here may be any solvent that dissolves each component, has an appropriate drying rate, and gives a uniform and smooth coating film after the solvent evaporates, and is usually used industrially in this field. A solvent can be used.

  For example, 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, esters such as ethyl lactate, butyl acetate, amyl acetate and ethyl pyruvate And ketones such as acetone, methyl isobutyl ketone, 2-heptanone and cyclohexanone, and cyclic esters such as γ-butyrolactone. These solvents can be used alone or in combination of two or more.

The resist composition of the present invention can form a resist pattern by the following method.
(1) A step of applying the above-described resist composition of the present invention on a substrate,
(2) a step of removing the solvent from the composition after coating to form 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.

The removal of the solvent is performed, for example, by evaporating the solvent using a heating device such as a hot plate or by using a decompression device to form a composition layer from which the solvent has been removed. 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 exposed using an exposure machine. Examples of the exposure machine include an immersion exposure machine. At this time, exposure is usually performed through a mask corresponding to a required pattern. The exposure light source emits ultraviolet laser light such as KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), F ₂ laser (wavelength 157 nm), solid-state laser light source (YAG or semiconductor laser, etc.) Various types of laser beam can be used, such as those that convert the wavelength of the laser beam from) to radiate a harmonic laser beam in the far ultraviolet region or the vacuum ultraviolet region.

The composition layer after the exposure is subjected to heat treatment for promoting 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.

  The salt of the present invention is suitably used as an acid generator for resist compositions exhibiting good resolution, and is particularly suitable for excimer laser lithography such as ArF and KrF, ArF immersion exposure lithography, electron beam lithography, and EUV lithography. It can be used as an acid generator for a suitable resist composition.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these.
In Examples and Comparative Examples, “%” and “part” representing content and use amount are based on mass unless otherwise specified. The weight average molecular weight is a value obtained 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)

  Moreover, the structure of the compound was confirmed by NMR (JEOL GX-270 type or EX-270 type) and mass spectrometry (LC: Agilent 1100 type, MASS: Agilent LC / MSD type or LC / MSD TOF type). .

Example 1: Synthesis of acid generator (I-5: A1)
1.66 parts of compound (I-5-a), 7.64 parts of toluene and 4.75 parts of diphosphorus pentoxide were charged, and the mixture was stirred at 23 ° C. for 30 minutes. To the obtained mixture, 0.32 part of methanesulfonic acid was added dropwise at 23 ° C. over 30 minutes, and the mixture was further stirred at 23 ° C. for 6 hours. To the obtained mixture, 24.60 parts of ion-exchanged water was added dropwise at 23 ° C. over 30 minutes, and the mixture was further stirred at 23 ° C. for 30 minutes and filtered. To the obtained filtrate, 1.38 parts of potassium iodide was added and stirred at 23 ° C. for 30 minutes, followed by filtration to obtain 2.22 parts of compound (I-5-b) as a white solid.

  To 100 parts of difluoro (fluorosulfonyl) acetic acid methyl ester and 150 parts of ion-exchanged water, 230 parts of a 30% aqueous sodium hydroxide solution was added dropwise in an ice bath. The resulting mixture was refluxed at 100 ° C. for 3 hours, cooled to 23 ° C. and neutralized with 88 parts of concentrated hydrochloric acid. The obtained mixture was concentrated to obtain 164.4 parts of difluorosulfoacetate sodium salt (containing inorganic salt, purity 62.7%). To 1.9 parts (purity 62.7%) of difluorosulfoacetic acid sodium salt and 9.5 parts of N, N-dimethylformamide, 1.0 part of 1,1′-carbonyldiimidazole was added for 2 hours. A mixture was prepared by stirring.

On the other hand, 0.2 part of sodium hydride was added to 1.1 parts of 3-hydroxyadamantyl methanol and 5.5 parts of N, N-dimethylformamide, and stirred for 2 hours. To this solution was added the above mixture. The resulting mixture was stirred for 15 hours, and the resulting solution containing difluorosulfoacetate-3-hydroxy-1-adamantylmethyl ester sodium salt (I-5-c) was used as such for the next reaction.

  To a solution prepared by adding 2.01 parts of compound (I-5-b) and 5.00 parts of chloroform, 0.72 part of silver chloride was added, and this was stirred at 23 ° C. for 12 hours. A solution containing 1.81 parts of compound (I-5-c) and 5.00 parts of ion-exchanged water were added to the chloroform solution, and 10.00 parts of chloroform was further added, followed by stirring at 23 ° C. for 12 hours. Thereafter, the filtrate was recovered by filtration. Since the obtained filtrate was separated into two layers, the chloroform layer was separated and taken out, and further, 10.00 parts of ion-exchanged water was added to the chloroform layer and washed with water. This operation was repeated three times. The chloroform layer was concentrated to obtain 2.80 parts of pale yellow oil. Crystals were precipitated by adding 14.00 parts of ethyl acetate to the obtained pale yellow oil and stirring. The crystals were filtered to obtain 1.42 parts (purity 100%, yield 46%) of compound (I-5) as a white solid. This compound (I-5) was designated as A1.

MS (ESI (+) Spectrum): M ^<+> 275.1
MS (ESI (-) Spectrum): M ^- 339.1
¹ H-NMR (dimethyl sulfoxide-d ₆ , internal standard substance tetramethylsilane): δ (ppm) 1.35 to 1.80 (m, 12H), 2.10 (m, 2H), 2.31 (s , 3H), 3.85 (s, 2H), 4.42 (s, 1H), 7.35-7.65 (m, 4H), 7.72 (t, 2H), 7.94 (t, 2H), 8.32 (d, 2H), 8.50 (d, 2H)

Example 2: Synthesis of acid generator (I-6: A2)

To 100 parts of difluoro (fluorosulfonyl) acetic acid methyl ester and 250 parts of ion-exchanged water, 230 parts of a 30% aqueous sodium hydroxide solution was added dropwise in an ice bath. The resulting mixture was refluxed at 100 ° C. for 3 hours, cooled to 23 ° C. and neutralized with 88 parts of concentrated hydrochloric acid. The obtained mixture was concentrated to obtain 164.8 parts of difluorosulfoacetate sodium salt (containing inorganic salt, purity 62.6%). To a mixture of 5.0 parts (purity 62.6%) of the obtained sodium difluorosulfoacetate, 2.6 parts of 4-oxo-1-adamantanol and 100 parts of ethylbenzene, 0.8 part of concentrated sulfuric acid was added, Heated to reflux for hours. The resulting mixture was cooled, filtered, and the resulting filter residue was washed with tert-butyl methyl ether to give difluorosulfoacetic acid-4-oxo-1-adamantyl ester sodium salt (I-6-c) 5 .5 parts were obtained.
As a result of purity analysis by ¹ H-NMR, the purity was 35.6%.

To a solution charged with 2.01 parts of compound (I-5-b) and 10.00 parts of chloroform, 0.72 parts of silver chloride was added, and the mixture was stirred at 23 ° C. for 12 hours. To the chloroform solution, 4.86 parts of compound (I-6-c) and 5.00 parts of ion-exchanged water were added, and 10.00 parts of chloroform was further added, followed by stirring at 23 ° C. for 12 hours. Thereafter, the filtrate was recovered by filtration. Since the obtained filtrate was separated into two layers, the chloroform layer was separated and taken out, and further, 10.00 parts of ion-exchanged water was added to the chloroform layer and washed with water. This operation was repeated three times. The chloroform layer was concentrated to obtain 2.94 parts of pale yellow oil. Crystals were precipitated by adding 15.00 parts of ethyl acetate to the obtained pale yellow oil and stirring. The crystals were filtered to obtain 1.19 parts of compound (I-6) as a white solid (purity 100%, yield 40%). Compound (I-6) was designated as A2.

MS (ESI (+) Spectrum): M ^<+> 275.1
MS (ESI (−) Spectrum): M ⁻ 323.0
¹ H-NMR (dimethyl sulfoxide-d ₆ , internal standard substance tetramethylsilane): δ (ppm) 1.83 (d, 2H), 2.00 (d, 2H), 2.29-2.32 (m , 7H), 2.31 (s, 3H), 2.53 (s, 2H), 7.35-7.65 (m, 4H), 7.72 (t, 2H), 7.94 (t, 2H), 8.32 (d, 2H), 8.50 (d, 2H)

Example 3: Synthesis of acid generator (I-7: A3)

  To 100 parts of difluoro (fluorosulfonyl) acetic acid methyl ester and 150 parts of ion-exchanged water, 230 parts of a 30% aqueous sodium hydroxide solution was added dropwise in an ice bath. The resulting mixture was refluxed at 100 ° C. for 3 hours and cooled. Thereafter, this was neutralized with 88 parts of concentrated hydrochloric acid. The obtained solution was concentrated to obtain 164.4 parts of sodium difluorosulfoacetate (containing inorganic salt, purity 62.7%).

30.0 parts of obtained difluorosulfoacetic acid sodium salt (purity 62.7%), hexahydro-6-hydroxy-3,5-methano-2H-cyclopenta [b] furan-2-one 14.7 parts and toluene 300 Then, 18.1 parts of p-toluenesulfonic acid was added and heated to reflux for 12 hours. Thereafter, the obtained mixture was filtered, and 100 parts of acetonitrile was added to the residue and stirred. Thereafter, the mixture was filtered and the obtained filtrate was concentrated to obtain 26.7 parts of compound (I-7-c).
As a result of purity analysis by ¹ H-NMR, the purity was 28.6%.

  To a solution charged with 2.01 parts of compound (I-5-b) and 10.00 parts of chloroform, 0.72 parts of silver chloride was added, and the mixture was stirred at 23 ° C. for 12 hours. The chloroform solution was charged with 5.84 parts of compound (I-7-c), and further 10.00 parts of chloroform was added, followed by stirring at 23 ° C. for 12 hours. Then, the organic layer was collect | recovered by concentrating and extracting the obtained mixture with 50 parts of chloroform. The collected organic layer was washed with ion exchange water. To the recovered organic layer, 1.2 parts of activated carbon was added, stirred and filtered. The obtained filtrate was concentrated, 10 parts of ethyl acetate was added and stirred, and the supernatant was removed. To the obtained residue, 10 parts of tert-butyl methyl ether was added and stirred, and the supernatant was removed. The obtained residue was dissolved in chloroform and concentrated to obtain 0.68 parts (purity 100%, yield 23%) of compound (I-7) as an amber oily substance. Compound (I-7) was designated as A3.

MS (ESI (+) Spectrum): M ^<+> 275.1
MS (ESI (-) Spectrum): M ^- 311.0
¹ H-NMR (dimethyl sulfoxide-d ₆ , internal standard substance tetramethylsilane): δ (ppm) 1.57-1.67 (m, 2H), 1.91-2.06 (m, 2H), 2 .31 (s, 3H), 2.53 (m, 2H), 3.21 (m, 1H), 4.51 (m, 1H), 4.62 (s, 1H), 7.35-7. 65 (m, 4H), 7.72 (t, 2H), 7.94 (t, 2H), 8.32 (d, 2H), 8.50 (d, 2H)

Example 4: Synthesis of acid generator (A4)

10.4 parts of lithium aluminum hydride and 120 parts of tetrahydrofuran were charged and stirred at 23 ° C. for 30 minutes. Next, a solution prepared by dissolving 62.2 parts of the salt represented by the formula (A4-a) in 900 parts of anhydrous THF was added dropwise under ice cooling, and the mixture was stirred at 23 ° C. for 5 hours. To the reaction mass, 50.0 parts of ethyl acetate and 50.00 parts of 6N hydrochloric acid were added, followed by liquid separation. After concentrating the organic layer, by separating the column (Merck silica gel 60-200 mesh developing solvent: chloroform / methanol = 5/1), 84.7 g of salt represented by the formula (A4-b) (purity 60%) )
Further, 4.5 parts of the compound represented by the formula (A4-c) and 90 parts of tetrahydrofuran were added and dissolved by stirring for 30 minutes at room temperature. To this solution, a mixed solution of 3.77 parts of carbonyldiimidazole and 45 parts of tetrahydrofuran was added dropwise at room temperature, and the mixture was stirred at 23 ° C. for 4 hours. The obtained reaction solution was added dropwise over 30 minutes at 54 to 60 ° C. while mixing 7.87 parts (purity 60%) of the salt represented by the formula (A4-b) and 50 parts of tetrahydrofuran. The reaction solution was heated at 65 ° C. for 18 hours, cooled and then filtered. The obtained filtrate is concentrated, and the concentrate is fractionated in a column (Merck silica gel 60-200 mesh developing solvent: chloroform / methanol = 5/1) to obtain a salt 4.97 represented by the formula (A4-d). Got a part.

  0.72 parts of silver chloride was added to a solution prepared by adding 2.01 parts of the salt represented by the formula (I-5-b) and 10.00 parts of chloroform, and the mixture was stirred at 23 ° C. for 12 hours. To the chloroform solution, 1.80 parts of the salt represented by the formula (A4-d) and 5.00 parts of ion-exchanged water were added, and further 10.00 parts of chloroform was added and stirred at 23 ° C. for 12 hours. Filtered. Since the collected filtrate was separated into two layers, the chloroform layer was separated and taken out, and further, 10.00 parts of ion-exchanged water was added to the chloroform layer and washed with water. This washing with water was performed three times. To the recovered organic layer, 1.0 part of activated carbon was added, stirred and filtered. The obtained filtrate was concentrated, 10 parts of ethyl acetate was added and stirred, and the supernatant was removed. To the obtained residue, 10 parts of tert-butyl methyl ether was added and stirred, and the supernatant was removed. The obtained residue was dissolved in chloroform and concentrated to obtain 1.24 parts of the salt represented by the formula (A4).

MS (ESI (+) Spectrum): M + 275.1
MS (ESI (-) Spectrum): M-337.1

Example 5: Synthesis of acid generator (A5)

10.4 parts of lithium aluminum hydride and 120 parts of tetrahydrofuran were charged and stirred at 23 ° C. for 30 minutes. Next, a solution prepared by dissolving 62.2 parts of the salt represented by the formula (A5-a) in 900 parts of tetrahydrofuran was added dropwise under ice cooling, and the mixture was stirred at 23 ° C. for 5 hours. To the reaction mass, 50.0 parts of ethyl acetate and 50.00 parts of 6N hydrochloric acid were added and stirred, followed by liquid separation. After concentration of the organic layer, by separating a column (Merck silica gel 60-200 mesh developing solvent: chloroform / methanol = 5/1), 84.7 g of salt represented by the formula (A5-b) (purity 60%) )
3.51 parts of the compound represented by the formula (A5-c) and 75 parts of tetrahydrofuran were charged and stirred at 23 ° C. for 30 minutes. Next, a mixed solution of 2.89 parts of carbonyldiimidazole and 50 parts of tetrahydrofuran was added dropwise at 23 ° C., and the mixture was stirred at 23 ° C. for 4 hours. The obtained reaction solution was dropped in a mixed solution of 6.04 parts (purity 60%) of the salt represented by the formula (A5-b) and 50 parts of tetrahydrofuran at 54 to 60 ° C. over 25 minutes, and 65 ° C. For 18 hours, cooled and filtered. The obtained filtrate is concentrated, and the concentrate is fractionated in a column (Merck silica gel 60-200 mesh developing solvent: chloroform / methanol = 5/1) to obtain a salt 2.99 represented by the formula (A5-d). Got a part.

  0.72 parts of silver chloride was added to a solution prepared by adding 2.01 parts of the salt represented by the formula (I-5-b) and 10.00 parts of chloroform, and the mixture was stirred at 23 ° C. for 12 hours. To the chloroform solution, 1.81 parts of the salt represented by the formula (A5-d) and 5.00 parts of ion-exchanged water are added, and further 10.00 parts of chloroform is added, followed by stirring at 23 ° C. for 12 hours and filtration. did. Since the collected filtrate was separated into two layers, the chloroform layer was separated and taken out, and further, 10.00 parts of ion-exchanged water was added to the chloroform layer and washed with water. This washing with water was performed three times. To the recovered organic layer, 1.0 part of activated carbon was added, stirred and filtered. The obtained filtrate was concentrated, 10 parts of ethyl acetate was added and stirred, and the supernatant was removed. To the obtained residue, 10 parts of tert-butyl methyl ether was added and stirred, and the supernatant was removed. The obtained residue was dissolved in chloroform and concentrated to obtain 1.01 part of the salt represented by the formula (A5).

MS (ESI (+) Spectrum): M + 275.1
MS (ESI (-) Spectrum): M- 339.1

[Synthesis of Resin (B1)]
Monomer A, monomer B and monomer C were charged in a molar ratio of 50:25:25, and then 1.5 mass times dioxane was added to the total mass of all monomers. To the obtained mixture, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) were added as initiators in proportions of 1 mol% and 3 mol%, respectively, with respect to the total number of moles of all monomers. This was heated at 80 ° C. for about 8 hours. Thereafter, the reaction solution was purified by pouring it into a large amount of a mixed solvent of methanol and water and precipitating three times. As a result, a copolymer having a weight average molecular weight of about 9.2 × 103 was obtained in a yield of 60%. This copolymer has a structural unit derived from each monomer of the following formula, and this was designated as resin B1.

[Synthesis of Resin B2]
39.7 g (0.16 mol) of 2-ethyl-2-adamantyl methacrylate and 103.8 g (0.64 mol) of p-acetoxystyrene were dissolved in 265 g of isopropanol and heated to 75 ° C. in a nitrogen atmosphere. . The radical initiator dimethyl 2,2-azobis (2-methylpropionate) 11.05 g (0.048 mol) was dissolved in 22.11 g of isopropanol and added dropwise. The reaction solution was heated to reflux for 12 hours. After cooling, the reaction solution was poured into a large amount of methanol, and the polymer was precipitated and filtered. The obtained copolymer of 2-ethyl-2-adamantyl methacrylate and p-acetoxystyrene was 250 g (containing methanol).

  250 g of the obtained copolymer and 10.3 g (0.084 mol) of 4-dimethylaminopyridine were added to 202 g of methanol and heated to reflux for 20 hours. After cooling, the reaction solution was neutralized with 7.6 g (0.126 mol) of glacial acetic acid and poured into a large amount of water to cause precipitation. The precipitated polymer was separated by filtration, dissolved in acetone, and then poured into a large amount of water for precipitation to be purified three times. The obtained copolymer of 2-ethyl-2-adamantyl methacrylate and p-hydroxystyrene was 95.9 g. The weight average molecular weight was about 8.6 × 103 (GPC polystyrene conversion), and the copolymerization ratio was about 20:80 (C13 NMR measurement). This resin is designated as B2.

[Synthesis of Resin B3]
Using 59.6 g (0.24 mol) of 2-ethyl-2-adamantyl methacrylate and 90.8 g (0.56 mol) of p-acetoxystyrene, the same operation as the synthesis of Resin B2 was carried out to obtain methacrylic acid. 102.8 g of a copolymer of 2-ethyl-2-adamantyl and p-hydroxystyrene was obtained. The weight average molecular weight was about 8.2 × 10 3 (converted to GPC polystyrene), and the copolymerization ratio was about 30:70 (C13 NMR measurement). This resin is designated as B3.

[Synthesis of Resin (B4)]
Monomer A, monomer B and monomer C were charged in a molar ratio of 50:25:25, and then 1.5 mass times dioxane was added to the total mass of all monomers. To the obtained mixture, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) were added as initiators at a ratio of 4 mol% and 12 mol%, respectively, with respect to the total number of moles of all monomers. This was heated at 80 ° C. for about 5 hours. Thereafter, the reaction solution was purified by pouring it into a large amount of methanol / water mixed solvent for precipitation three times to obtain a copolymer having a weight average molecular weight of about 3.0 × 103 at a yield of 70%. Obtained. This copolymer has a structural unit derived from each monomer of the following formula, and this was designated as resin B4.

[Synthesis of resin fat B5]
Using the radical initiator dimethyl 2,2-azobis (2-methylpropionate) 44.20 g (0.192 mol), the same operation as in the synthesis of the resin B2 was carried out to give 2-ethyl-2-methacrylate 82.4 g of adamantyl and p-hydroxystyrene copolymer was obtained. The weight average molecular weight was about 3.0 × 103 (GPC polystyrene conversion), and the copolymerization ratio was about 20:80 (C13 NMR measurement). This resin is designated as B5.

[Synthesis of Resin B6]
Using the radical initiator dimethyl 2,2-azobis (2-methylpropionate) 44.20 g (0.192 mol), the same operation as in the synthesis of the resin B2 was carried out to give 2-ethyl-2-methacrylate 93.6 g of adamantyl and p-hydroxystyrene copolymer was obtained. The weight average molecular weight was about 3.0 × 103 (GPC polystyrene conversion), and the copolymerization ratio was about 30:70 (C13 NMR measurement). This resin is designated as B6.

[Synthesis of Resin B7]
75.00 g (0.32 mol) of 2-methyl-2-adamantyl methacrylate and 77.85 g (0.48 mol) of p-acetoxystyrene were dissolved in 285 g of isopropanol and heated to 75 ° C. in a nitrogen atmosphere. . Radical initiator dimethyl 2,2-azobis (2-methylpropionate) 41.44 g (0.180 mol) was dissolved in isopropanol 82.88 g and added dropwise. The reaction solution was heated to reflux for 12 hours. After cooling, the reaction solution was poured into a large amount of methanol, and the polymer was precipitated and filtered. The obtained copolymer of 2-methyl-2-adamantyl methacrylate and p-acetoxystyrene was 275 g (containing methanol).

  275 g of the obtained copolymer and 10.3 g (0.084 mol) of 4-dimethylaminopyridine were added to 200 g of methanol and heated to reflux for 20 hours. After cooling, the reaction solution was neutralized with 7.6 g (0.126 mol) of glacial acetic acid and poured into a large amount of water to cause precipitation. The precipitated polymer was separated by filtration, dissolved in acetone, poured into a large amount of water and precipitated, and purified by repeating three times. The obtained copolymer of 2-methyl-2-adamantyl methacrylate and p-hydroxystyrene was 88.6 g. The weight average molecular weight was about 4.0 × 103 (in terms of GPC polystyrene), and the copolymerization ratio was about 40:60 (C13 NMR measurement). This resin is designated as B7.

Examples 6-20 and Comparative Examples 1-2
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.

<Acid generator>
Acid generator C1
<Quencher>
Quencher Q1: 2,6-diisopropylaniline Quencher Q2: Tetrabutylammonium hydroxide <solvent>
Propylene glycol monomethyl ether acetate 300 parts Propylene glycol monomethyl ether 20.0 parts γ-butyrolactone 3.0 parts

(Evaluation as a resist composition for ArF exposure)
An organic antireflective coating composition (ARC-29; manufactured by Nissan Chemical Co., Ltd.) is applied to a silicon wafer and baked at 205 ° C. for 60 seconds to form an organic antireflective coating having a thickness of 78 nm. Formed.
Next, the above resist composition was spin-coated on the organic antireflection film so that the film thickness after drying was 85 nm.
After application of the composition, the obtained silicon wafer was pre-baked on a direct hot plate at a temperature shown in the PB column of Table 1 for 60 seconds.

Using the ArF excimer stepper [FPA5000-AS3; manufactured by Canon Inc., NA = 0.75, 2 / 3Annular] on the silicon wafer on which the film of the chemically amplified resist composition is formed in this manner, the exposure amount is stepwise. And the line and space pattern was exposed.
After exposure, post-exposure baking was performed for 60 seconds at the temperature shown in the PEB column of Table 1 on a hot plate, and paddle development was further performed for 60 seconds with an aqueous 2.38 wt% tetramethylammonium hydroxide solution.

  Resolution evaluation: The pattern when exposed with an exposure amount at which a 100 nm line and space pattern is 1: 1 is observed with a scanning electron microscope, ○ indicates that 90 nm is resolved, ○, not resolved × It was. The results are shown in Table 4.

(Evaluation as a resist composition for electron beams)
The silicon wafer was treated on a direct hot plate with hexamethyldisilazane at 90 ° C. for 60 seconds, and the resist composition was spin-coated so that the film thickness after drying was 0.06 μm.
After applying the resist solution, it was pre-baked on a direct hot plate for 60 seconds at the temperature shown in the PB column of Table 2.
Each wafer with the resist film thus formed is exposed to a line-and-space pattern by using an electron beam drawing machine ["HL-800D 50 keV" manufactured by Hitachi, Ltd. and changing the exposure stepwise. did.
After the exposure, post-exposure baking was performed for 60 seconds at the temperature shown in the PEB column of Table 2 on a hot plate, and paddle development was further performed for 60 seconds with an aqueous 2.38 wt% tetramethylammonium hydroxide solution.
The developed pattern on the silicon substrate was observed with a scanning electron microscope. The results are shown in Table 5.

  Resolution evaluation: A pattern of 100 nm line and space pattern exposed at an exposure amount of 1: 1 is observed with a scanning electron microscope, ○ indicates that 60 nm is resolved, ○, not resolved × It was.

(Evaluation as a resist composition for EUV)
The silicon wafer was treated with hexamethyldisilazane at 90 ° C. for 60 seconds on a direct hot plate, and the resist composition was spin-coated so that the film thickness after drying was 0.05 μm.
After applying the resist solution, it was pre-baked on a direct hot plate at the temperature shown in the PB column of Table 3 for 60 seconds. Each wafer on which the resist film was formed in this manner was exposed to a line and space pattern using an EUV exposure machine while changing the exposure amount stepwise. After the exposure, post-exposure baking was performed for 60 seconds at a temperature shown in the PEB column of Table 3 on a hot plate, and paddle development was further performed for 60 seconds with an aqueous 2.38 wt% tetramethylammonium hydroxide solution.
The pattern after development on the silicon substrate was observed with a scanning electron microscope. The results are shown in Table 6.

  Resolution evaluation: Observed with a scanning electron microscope when a 50 nm line-and-space pattern is exposed at an exposure amount of 1: 1, ○ indicates that 44 nm is resolved, ○ indicates no resolution × It was.

  According to the salt of the present invention, a pattern having excellent resolution can be formed using a resist composition containing the salt.

Claims (6)

A salt represented by the formula (I).
[In the formula (I),
Q ¹ and Q ² each independently represent a fluorine atom or a trifluoromethyl group.
X ¹ is, -CO-O-X ¹⁰ - or -X ¹¹ -O-CO - represents, X ¹⁰ and X ^11, independently of one another, a single bond, a linear or branched C 1-15 Represents an alkylene group.
Y ¹ represents an alicyclic hydrocarbon group represented by the following formula (Y1) or formula (Y2), and the hydrogen atom contained in the alicyclic hydrocarbon group is replaced by a hydroxy group, a methylene group contained in the alicyclic hydrocarbon groups that substituted by a carbonyl group.
R ^e1 to R ^e13 are each independently represent a hydrogen atom or A alkyl group.
Z represents a single bond . ]
The salt according to claim 1, wherein X ¹ is —CO—O— [CH ₂ ] _h — (h represents an integer of 0 to 10). The acid generator containing the salt of Claim 1 or 2 . The acid generator according to claim 3 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 A resist composition comprising the resist composition according to claim 4 and a basic compound. (1) The process of apply | coating the resist composition of Claim 4 or 5 on a board | substrate,
(2) a step of removing the solvent from the composition after coating to form a composition layer;
(3) a step of exposing the composition layer using an exposure machine;
(4) A pattern forming method including a step of heating the composition layer after exposure, and (5) a step of developing the composition layer after heating using a developing device.