JP5512431B2 - Polymer, photoresist composition and pattern production method - Google Patents

Description

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

A resist composition used for microfabrication of a semiconductor using a lithography technique contains a resin.
For example, Patent Document 1 describes a resist composition containing a polymer represented below as a resin.

  JP 2006-178317 A

  In the conventional salt, the resolution and shape of the pattern formed using the resist composition containing a polymer having a repeating unit derived from the salt may not always be satisfied.

The present application includes the following inventions.
[1] A salt represented by the formula (IB).
[In the formula (IB),
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 divalent aliphatic hydrocarbon group having 1 to 36 carbon atoms, a divalent alicyclic hydrocarbon group having 3 to 36 carbon atoms, or a divalent group having 6 to 36 carbon atoms. The aliphatic hydrocarbon group, the alicyclic hydrocarbon group and the aromatic hydrocarbon group may have a substituent, and the aliphatic hydrocarbon group, alicyclic The methylene group contained in the hydrocarbon group and the aromatic hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
Y ^A represents a vinyl group, acryloyl group, methacryloyl group, acryloyloxy group or methacryloyloxy group which may have a substituent.
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. However, R ^{e1 to} R ^{e13 do not} include a vinyl group, an acryloyl group, a methacryloyl group, an acryloyloxy group, or a methacryloyloxy group.
Z represents a single bond or a divalent linking group. ]

[2] The salt according to [1], wherein Z is a single bond.
[3] The salt according to [1] or [1], 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. ]
[5] An acid generator containing the salt according to any one of [1] to [4].
[6] A polymer having a repeating unit derived from the salt according to any one of [1] to [4].
[7] The polymer according to [6], further comprising a repeating unit derived from a monomer that is insoluble or hardly soluble in an alkaline aqueous solution and is soluble in the alkaline aqueous solution by the action of an acid.

[8] A photoresist composition comprising the acid generator according to [5] above.
[9] A photoresist composition containing the polymer described in [6] or [7].
[10] A photoresist composition comprising the acid generator described in [5] above and the polymer described in [6] or [7].
[11] The photoresist composition according to any one of [8] to [10], further containing a basic compound.
[12] (1) A step of applying the photoresist composition according to any one of [8] to [10] 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 and shape can be formed using a resist composition containing a polymer having a repeating unit derived from the salt.

The salt of the present invention is represented by the formula (IB) (hereinafter sometimes referred to as “salt (IB)” or “compound (IB)”).
A salt represented by the formula (IB).
[In the formula (IB),
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 divalent aliphatic hydrocarbon group having 1 to 36 carbon atoms, a divalent alicyclic hydrocarbon group having 3 to 36 carbon atoms, or a divalent group having 6 to 36 carbon atoms. The aliphatic hydrocarbon group, the alicyclic hydrocarbon group and the aromatic hydrocarbon group may have a substituent, and the aliphatic hydrocarbon group, alicyclic The methylene group contained in the hydrocarbon group and the aromatic hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
Y ^A represents a vinyl group, acryloyl group, methacryloyl group, acryloyloxy group or methacryloyloxy group which may have a substituent.
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. However, R ^{e1 to} R ^{e13 do not} include a vinyl group, an acryloyl group, a methacryloyl group, an acryloyloxy group, or a methacryloyloxy group.
Z represents a single bond or a divalent linking 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 linear or branched C1-C15 alkylene group mutually independently. Among _{them, -CO-O- [CH 2]} h - (h is an integer of 0) are preferred.

Examples of the substituent which may be substituted with the aliphatic hydrocarbon group, alicyclic hydrocarbon group and aromatic hydrocarbon group of Y ¹ include, for example, a halogen atom, a hydroxyl group, an alkyl group having 1 to 12 carbon atoms, carbon 1 or more selected from the group consisting of 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, a glycidyloxy group, or an acyl group having 2 to 4 carbon atoms. .

  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.

The substituent in Y ^A, for example, a hydroxyl group, a cyano group, an alkyl group having 1 to 6 carbon atoms.

  Examples of the anion of the salt represented by the formula (IB) include the formula (IA-P), the formula (IB-P), the formula (IC-P), the formula (ID-P), and the like. Preferable examples include anions represented by formula (IA-P) and formula (IB-P).

[In formula (IA-P), formula (IB-P), formula (IC-P) and formula (ID-P),
Q ¹ , Q ² , Y ¹ and Y ^A represent the same meaning as in formula (IB).
X ¹⁰ , X ¹¹ and X ¹² each independently represent a linear or branched alkylene group having 1 to 15 carbon atoms. ]

  Among them, the anion of the salt represented by the formula (IB) includes the formula (IA-P ′), the formula (IB-P ′), the formula (IC-P ′), and the formula (ID-P ′). Etc. Preferable examples include anions represented by formula (IA-P ′) and formula (IB-P ′).

[In formula (IA-P ′), formula (IB-P ′), formula (IC-P ′) and formula (ID-P ′),
Q ¹ , Q ² and Y ¹ represent the same meaning as in formula (IB).
X ¹⁰ , X ¹¹ and X ¹² represent the same meaning as described above.
R ^{1 ′} represents a hydroxyl group, a cyano group, or an alkyl group having 1 to 6 carbon atoms. ]

Y ¹ is preferably a divalent group represented by the formula (III).
[In the formula (III),
Ring W ′ represents a divalent alicyclic hydrocarbon group having 3 to 36 carbon atoms or a divalent aromatic hydrocarbon group having 6 to 36 carbon atoms, and a methylene group contained in the alicyclic hydrocarbon group. May be replaced by an oxygen atom or a carbonyl group.
R ^b is independently of each other a halogen atom, a hydroxyl group, a linear or branched aliphatic hydrocarbon group having 1 to 12 carbon atoms, an aromatic hydrocarbon group having 6 to 20 carbon atoms, or 7 to 21 carbon atoms. An aralkyl group, an alkoxy group having 1 to 12 carbon atoms, a glycidoxy 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. ]

x preferably represents an integer of 0 to 6, more preferably an integer of 0 to 4.
Examples of the ring W ′ include groups represented by formulas (W1) to (W28). Preferred examples include groups represented by formula (W3), formula (W4), formula (W8), formula (W9), formula (W12) and formula (W13).

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. ]

Examples of the anion represented by the formula (IA) include the following.

Examples of the anion represented by the formula (IB) include the following.

Specific examples of the anion represented by the formula (IC) include the following.

Specific examples of the anion represented by the formula (ID) include the following.

The cation of the salt represented by the formula (IB) is represented by the formula (BB).

[In the formula (BB)
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. However, R ^{e1 to} R ^{e13 do not} include a vinyl group, an acryloyl group, a methacryloyl group, an acryloyloxy group, or a methacryloyloxy group.
Z represents a single bond or a divalent linking group. ]

Examples of the substituent in R ^{e1 to} R ^e13 include a hydroxyl group, a halogen atom, 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, an aryloxy group, Silyloxy group, heterocyclic oxy group, acyloxy group, carbamoyloxy group, alkoxycarbonyloxy group, aryloxycarbonyloxy group, amino group, ammonio group, acylamino group, aminocarbonylamino group, alkoxycarbonylamino group, aryloxycarbonylamino 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 group, acyl group, aryloxycarbonyl group, alkoxycarbonyl group, carbamoyl group, aryl and heterocyclic azo group, imide group, phosphino group, phosphinyl group, phosphinyloxy group, phosphinylamino group, phosphono 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.
For example, 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, benzofuran ring, benzothiophene ring, isobenzofuran ring, quinolidine ring, quinoline ring, phthalazine ring, naphthyridine ring, quinoxaline ring, quinoxazoline ring, isoquinoline ring, carbazole ring, phenant Examples include lysine ring, acridine ring, phenanthroline ring, thianthrene ring, chromene ring, xanthene ring, phenoxathiin ring, phenothiazine ring, and phenazine ring.

R ^{e1 to} R ^e13 are preferably a hydroxyl group, halogen atom, alkyl group, alkenyl group, alkynyl group, aryl group, cyano group, carboxyl group, alkoxy group, aryloxy group, acyloxy group, 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, aryloxycarbonyl group, An alkoxycarbonyl group, a carbamoyl group, an imide group, a silyl group, and a ureido group.

More preferably, a hydroxyl group, halogen atom, alkyl group, cyano group, alkoxy group, acyloxy group, acylamino group, aminocarbonylamino group, alkoxycarbonylamino group, alkyl and arylsulfonylamino group, alkylthio group, sulfamoyl group, alkyl and aryl A sulfonyl group, an alkoxycarbonyl group, and a carbamoyl group;
Particularly preferred are a hydroxyl group, an alkyl group, a halogen atom and an alkoxy 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. A sulfonyl group, —CH═CH—, —C≡C—, aminocarbonylamino group, aminosulfonylamino group and the like can be mentioned. These may further have a substituent.

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, or the like. .
More preferably, a single bond, an ether group, and a thioether group are mentioned.
Particularly preferred is a single bond.

Examples of the cation represented by the formula (BB) include the following.
(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 (BB) include the following compounds.
The anions and cations described above can be arbitrarily combined.

For example, the salt represented by the formula (IB) includes any of the following compounds. When such a compound is used as an acid generator, a resist composition showing good resolution can be provided.
(In the formula, R ^e1 , R ^e5 , R ^e9 and t have the same meaning as described above.)
t is preferably 0 to 1.

Of the above combinations, specifically, the following salts are preferable.

In the compound represented by the formula (IB), the acid generator when the cation is Z ⁺ is, for example, a salt represented by the formula (1) and (meth) represented by the formula (2). Examples thereof include a method in which an acrylic acid derivative is stirred and reacted in an inert solvent in a temperature range of about −30 to 200 ° C., preferably in a temperature range of about 0 to 150 ° C.
Here, examples of the inert solvent include toluene, tetrahydrofuran, dimethylformamide, dimethyl sulfoxide and the like.
In the reaction, a dehydrohalogenating agent is preferably added. For example, an organic base such as triethylamine or pyridine, an inorganic base such as potassium carbonate or sodium hydroxide, or a mixture thereof is used.

[Wherein, Q ¹ , Q ² , X ¹ , Y ¹ and Y ^A represent the same meaning as in formula (IB), and X ^x represents a halogen atom. ]

The amount of the (meth) acrylic acid derivative represented by the formula (2) is equivalent to 2 times, preferably equivalent to 1.5 times the amount of 1 mol of the sulfonium salt derivative represented by the formula (1). is there.
The amount of the dehydrohalogenating agent is from equivalent to 5 times, preferably from equivalent to 3 times.

A phase transfer catalyst such as tetrabutylammonium bromide can be added to the reaction.
The resulting condensate can be removed by ordinary post-treatment. This condensate can be purified by chromatography, recrystallization, distillation and the like.

As for the manufacturing method of the cation in the salt represented by a formula (IB), the manufacturing method represented by the following reaction formula is mentioned, for example.
[In formula, R ^<e1 > -R ^<e13 > and Z represent the same meaning as the above. ]

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

  A compound represented by the formula (BB-A) and a compound represented by the formula (BB-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 BB) 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 salt represented by the formula (IB) can be used as an acid generator. In this case, the salt represented by the formula (IB) may be used alone or in combination of two or more. Further, the acid generator of the present invention further includes a known salt other than the salt represented by the formula (IB), that is, a cation and a known anion contained in the salt represented by the formula (IB). And an anion contained in the salt represented by the formula (BB) and a salt composed of a known cation.

The polymer of the present invention has a repeating unit derived from the salt represented by the formula (IB). In this polymer, a salt represented by the formula (IB) may be used singly or in combination. Further, it may be a polymer containing only the formula (IB), but as will be described later, compounds other than the salt represented by the formula (IB) (for example, various constituents constituting the resin described later) Monomer) may be used as a polymer (resin).
The polymer which has a repeating unit derived from the compound represented by a formula (IB) can be manufactured by a well-known method in the said field | area mentioned later.

The resist composition of the present invention contains at least a polymer having a repeating unit derived from the salt of formula (IB) using the salt of formula (IB) described above as an acid generator. The resist composition may contain both a salt of formula (IB) as an acid generator and a polymer having a repeating unit derived from the salt of formula (IB). It may further contain a resin known or known in the art or an acid generator known in the art.
The polymer or resin described above contained in the resist composition preferably has an acid labile group. As a result, the polymer or resin that is insoluble or hardly soluble in the alkaline aqueous solution and acts with the acid can be dissolved in the alkaline aqueous solution.

In this resist composition, an acid is generated from the salt represented by the formula (IB) by exposure. The acid catalyzes and cleaves the acid labile group in the resin, making the resin or polymer soluble in an aqueous alkaline solution. Such a photoresist composition is suitable as a chemically amplified resist composition, particularly as a positive photoresist composition.
However, in the photoresist 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 is a carbon at the α-position of an ether bond. It is preferred that the atom is 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 of the resin 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 include adamantyl, 2-ethyl-2-adamantyl methacrylate, 2-n-butyl-2-adamantyl acrylate, and the like. Examples of the α-chloro-2-alkyl-2-adamantyl α-chloroacrylate include 2-methyl-2-adamantyl α-chloroacrylate, 2-ethyl-2-adamantyl α-chloroacrylate, and the like.

  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 a hydroxyl group or the like may be bonded to the 1-adamantyl ester.

  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.

  Specific 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 a hydroxyl group such as the following, and mixtures thereof. It is done. 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 radically polymerizing the corresponding (meth) acrylic acid ester monomer, acetoxystyrene, and styrene and then deacetylating 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 preferable.

  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. ]
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.

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%.

  As structural units derived from monomers having acid-labile groups, in particular, 2-alkyl-2-adamantyl methacrylate, 2-alkyl-2-adamantyl acrylate 1- (1-adamantyl) -1-alkyl methacrylate When a structural unit derived from alkyl, 2-alkyl-2-adamantyl methacrylate 1- (1-adamantyl) -1-alkylalkyl acrylate is included, the structural unit is 15 of all structural units constituting the resin. When it is at least mol%, the resin has an alicyclic group, so that it has a sturdy structure, which is advantageous in terms of dry etching resistance of the resist to be provided.

  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, You may use together the monomer from which the combination of an acid labile group and an olefinic double bond differs.

  The polymer or resin in the resist composition of the present invention has a structural unit derived from the salt represented by the formula (IB) and a structural unit derived from a monomer having an acid labile group. The proportion of the structural unit derived from the salt represented by the formula (IB) is preferably 5 to 100%, more preferably 10 to 70, based on the total weight of the resin component in the resist composition. %.

  The weight average molecular weight of the resin or polymer is preferably 2,500 or more and 100,000 or less, more preferably 2,700 or more and 50,000 or less, and further preferably 3,000 or more and 40,000 or less. .

The formula (I-B) and good acid generators may be used together, in the anion of the salt represented by the formula (I-B), the anionic substituent Y ^A is unsubstituted, i.e.,
(In the formula, Q ¹ , Q ² , X ¹ and Y ¹ represent the same meaning as in formula (IB)).
The salt which combined the anion represented by these and the cation shown below arbitrarily is mentioned.
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 and a C 6 to 20 carbon atom that may be substituted with a cycloalkyl group having 3 to 12 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, a cation represented by the formula (IXa) and the like are 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.
np1 to np3 are integers of 0 to 5 independently of each other. ]

  Examples of the cyclic hydrocarbon group include those containing an adamantyl skeleton and an isobornyl skeleton, preferably a 2-alkyl-2-adamantyl group, a 1- (1-adamantyl) -1-alkyl group, and an 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.
np22 to np24 are integers of 0 to 5 independently of each other. ]

  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.

  In addition, the acid generator mentioned above can be formed with the following manufacturing methods. In the formulas shown in the following methods for producing an acid generator, the definitions of the substituents have the same meaning as described above unless otherwise specified.

  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 an 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.

  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 about 80 to 99.9% by weight of resin and about 0.1 to 20% by weight of acid generator based on the total solid content.
Further, when a basic compound that is a quencher is used as the chemically amplified resist composition, it is preferably contained in a range of about 0.01 to 1% by weight based on the total solid content of the resist composition.
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 be used in a resist pattern forming method. For example, the resist pattern can be formed by the following method.
(1) The process of apply | coating the resist composition of this invention mentioned above 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 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 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-1: A1)
1.66 parts of compound (I-1-a), 7.64 parts of toluene, and 4.75 parts of diphosphorus pentoxide were charged and 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, stirred at 23 ° C. for 30 minutes, and filtered to obtain Compound (I-1-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. Then, it cooled to 23 degreeC 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 obtained mixture was stirred for 15 hours, and the resulting solution containing difluorosulfoacetate-3-hydroxy-1-adamantylmethyl ester sodium salt (I-1-c) was used as it was in the next reaction.

  To a solution charged with 2.01 parts of compound (I-1-b) and 5.00 parts of chloroform, 0.72 parts of silver chloride was added, and the mixture was stirred at 23 ° C. for 12 hours. A solution containing 1.81 parts of compound (I-1-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 and filtration. The filtrate was recovered. Since the obtained filtrate was separated into two layers, the chloroform layer was separated and taken out. Furthermore, 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, and filtered to obtain 1.42 parts of compound (I-1-d) as a white solid (purity 100%, yield). 46%).

  1.23 parts of compound (I-1-d), 0.30 part of 1-methylpyrrolidine and 15 parts of chloroform were added, 0.63 part of methacrylic acid chloride was added with stirring, and the mixture was stirred at 30 ° C. for 2 hours. To the obtained mixture, 10.0 parts of chloroform and 10.0 parts of ion-exchanged water were added and separated to recover the organic layer. To the recovered organic layer, 10.0 parts of saturated aqueous sodium hydrogen carbonate was added and separated to recover the organic layer. To the recovered organic layer, 10.0 parts of a saturated aqueous ammonium chloride solution was added for washing, and the organic layer was recovered by liquid separation. Furthermore, 10.0 parts of ion-exchanged water was added to the recovered organic layer and separated to recover the organic layer. The collected organic layer was concentrated, 8 parts of ethyl acetate was added and stirred, and the supernatant was removed. To the obtained residue, 8 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 0.42 parts (purity 99.5%, yield 31%) of compound (I-1) as an amber oily substance. Compound (I-1) was designated as salt A1.

MS (ESI (+) Spectrum): M ^<+> 275.1
MS (ESI (-) Spectrum): M ^- 407.1
¹ H-NMR (dimethylsulfoxide-d ₆ , internal standard substance tetramethylsilane): δ (ppm) 1.45-2.18 (m, 17H), 1.95 (s, 3H), 3.91 (s , 2H); 5.57 (m, 1H); 5.91 (m, 1H), 7.35-7.60 (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-8: A2) Example 1 except that 1.1 parts of 3-hydroxyadamantyl methanol in Example 1 are replaced with 1.2 parts of 3,5-dihydroxyadamantyl methanol. Compound (I-8) is obtained by the same method. In this compound, (I-8) is designated as salt A2.

MS (ESI (+) Spectrum): M ^<+> 275.1
MS (ESI (-) Spectrum): M ^- 423.1

Example 3: Synthesis of acid generator (A3)
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 obtained by dissolving 62.2 parts of the salt represented by the formula (A3-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, 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 (A3-b) (purity 60%) )
3.51 parts of the compound represented by the formula (A3-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 into a mixture of 6.04 parts (purity 60%) of the salt represented by the formula (A3-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 2.99 of the salt represented by the formula (A3-d). Got a part.

To a solution prepared by adding 2.01 parts of the salt represented by the formula (I-1-b) and 10.00 parts of chloroform, 0.72 parts of silver chloride was added and stirred at 23 ° C. for 12 hours. To the chloroform solution, 1.81 parts of the salt represented by the formula (A3-d) and 5.00 parts of ion-exchanged water were added, and further 10.00 parts of chloroform was 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 parts of the salt represented by the formula (A3-e).

  0.62 part of the salt represented by the formula (A3-e), 0.15 part of 1-methylpyrrolidine and 15 parts of chloroform were added, and 0.32 part of methacrylic acid chloride was added with stirring and stirred at 30 ° C. for 2 hours. did. To the obtained mixture, 10.0 parts of chloroform and 10.0 parts of ion-exchanged water were added and separated to recover the organic layer. To the recovered organic layer, 10.0 parts of saturated aqueous sodium hydrogen carbonate was added and separated to recover the organic layer. To the recovered organic layer, 10.0 parts of a saturated aqueous ammonium chloride solution was added for washing, and the organic layer was recovered by liquid separation. Furthermore, 10.0 parts of ion-exchanged water was added to the recovered organic layer and separated to recover the organic layer. The collected organic layer was concentrated, 5 parts of ethyl acetate was added and stirred, and the supernatant was removed. To the obtained residue, 5 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 0.18 parts of the salt represented by the formula (A3). The salt represented by the formula (A3) was designated as salt A3.

MS (ESI (+) Spectrum): M ^<+> 275.1
MS (ESI (-) Spectrum): M ^- 407.1

[Synthesis of Resin (B1)]
Monomer A and p-acetoxystyrene were charged at a molar ratio of 20:80, and then 1.5 parts by mass of isopropanol was added to the total mass of all monomers. To the obtained mixture, dimethyl 2,2-azobis (2-methylpropionate) as an initiator was added at a ratio of 6 mol% with respect to the total number of moles of all monomers, and this was added at 75 ° C. for about 12 hours. Heated. Thereafter, the reaction solution was poured into a large amount of methanol and precipitated to obtain a copolymer.
The obtained copolymer and 3.0 mass times methanol with respect to the copolymer mass were charged, and then 10 mol with respect to the total number of moles of all monomers before copolymerization of 4-dimethylaminopyridine. %, And heated to reflux for 20 hours. After cooling, the reaction solution was neutralized with glacial acetic acid and poured into a large amount of water to cause precipitation. The precipitated polymer was filtered off and dissolved in acetone. Then, the operation of pouring into a large amount of water and precipitating was repeated three times to obtain a copolymer having a weight average molecular weight of about 8600 in a yield of 68%. This copolymer was designated as resin B1.

[Synthesis of Resin (B2)]
Monomer A and p-acetoxystyrene were charged at a molar ratio of 30:70, and then 1.5 parts by mass of isopropanol was added to the total mass of all monomers. To the obtained mixture, dimethyl 2,2-azobis (2-methylpropionate) as an initiator was added at a ratio of 6 mol% with respect to the total number of moles of all monomers, and this was added at 75 ° C. for about 12 hours. Heated. Thereafter, the reaction solution was poured into a large amount of methanol and precipitated to obtain a copolymer.
The obtained copolymer and 3.0 mass times methanol with respect to the copolymer mass were charged, and then 10 mol with respect to the total number of moles of all monomers before copolymerization of 4-dimethylaminopyridine. %, And heated to reflux for 20 hours. After cooling, the reaction solution was neutralized with glacial acetic acid and poured into a large amount of water to cause precipitation. The precipitated polymer was filtered off and dissolved in acetone. Then, the operation of pouring into a large amount of water and precipitating was repeated three times for purification, and a copolymer having a weight average molecular weight of about 8200 was obtained in a yield of 65%. This copolymer was designated as resin B2.

Example 4: [Synthesis of Resin (B3)]
Monomer A, p-acetoxystyrene and salt A1 were charged at a molar ratio of 20:70:10, and then 1.5 mass times acetonitrile was added to the total mass of all monomers. To the obtained mixture, dimethyl 2,2-azobis (2-methylpropionate) as an initiator was added at a ratio of 6 mol% with respect to the total number of moles of all monomers, and this was added at 75 ° C. for about 12 hours. Heated. Thereafter, the reaction solution was poured into a large amount of methanol and precipitated to obtain a copolymer.
The obtained copolymer and 3.0 mass times acetonitrile with respect to the copolymer mass were charged, and then 10 mol to the total number of moles of all monomers before copolymerization of 4-dimethylaminopyridine. %, And heated to reflux for 20 hours. After cooling, the reaction solution was neutralized with glacial acetic acid and poured into a large amount of water to cause precipitation. The precipitated polymer was filtered off and dissolved in acetone. Then, the operation of pouring into a large amount of water and precipitating was repeated three times to purify, and a copolymer having a weight average molecular weight of about 6200 was obtained in a yield of 42%. This copolymer was designated as resin B3.

Example 5: [Synthesis of Resin (B4)]
Monomer A, p-acetoxystyrene and salt A1 were charged at a molar ratio of 30:60:10, and then 1.5 mass times acetonitrile was added to the total mass of all monomers. To the obtained mixture, dimethyl 2,2-azobis (2-methylpropionate) as an initiator was added at a ratio of 6 mol% with respect to the total number of moles of all monomers, and this was added at 75 ° C. for about 12 hours. Heated. Thereafter, the reaction solution was poured into a large amount of methanol and precipitated to obtain a copolymer.
The obtained copolymer and 3.0 mass times acetonitrile with respect to the copolymer mass were charged, and then 10 mol to the total number of moles of all monomers before copolymerization of 4-dimethylaminopyridine. %, And heated to reflux for 20 hours. After cooling, the reaction solution was neutralized with glacial acetic acid and poured into a large amount of water to cause precipitation. The precipitated polymer was filtered off and dissolved in acetone. Thereafter, the operation of pouring into a large amount of water and precipitating was repeated three times for purification, and a copolymer having a weight average molecular weight of about 6400 was obtained in a yield of 44%. This copolymer was designated as resin B4.

Reference Example 6: [Synthesis of Resin B5]
The salt A1 and 1.5 mass times dioxane of the salt A1 were added. To the obtained mixture, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added at a ratio of 1 mol% and 3 mol%, respectively, with respect to the number of moles of the salt A1. This was heated at 77 ° 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 5700 in a yield of 49%. This copolymer was designated as resin B5.

Example 7: [Synthesis of Resin (B6)]
Monomer A, p-acetoxystyrene and salt A1 were charged at a molar ratio of 25:65:10, and then 1.5 mass times acetonitrile was added to the total mass of all monomers. To the obtained mixture, dimethyl 2,2-azobis (2-methylpropionate) as an initiator was added at a ratio of 6 mol% with respect to the total number of moles of all monomers, and this was added at 75 ° C. for about 12 hours. Heated. Thereafter, the reaction solution was poured into a large amount of methanol and precipitated to obtain a copolymer.
The obtained copolymer and 3.0 mass times acetonitrile with respect to the copolymer mass were charged, and then 10 mol to the total number of moles of all monomers before copolymerization of 4-dimethylaminopyridine. %, And heated to reflux for 20 hours. After cooling, the reaction solution was neutralized with glacial acetic acid and poured into a large amount of water to cause precipitation. The precipitated polymer was filtered off and dissolved in acetone. Thereafter, the operation of pouring into a large amount of water and precipitating was repeated three times for purification, and a copolymer having a weight average molecular weight of about 7000 was obtained in a yield of 53%. This copolymer was designated as resin B6.

Example 8: [Synthesis of Resin (B7)]
Monomer A, p-acetoxystyrene and salt A3 were charged at a molar ratio of 25:65:10, and then 1.5 mass times acetonitrile was added to the total mass of all monomers. To the obtained mixture, dimethyl 2,2-azobis (2-methylpropionate) as an initiator was added at a ratio of 6 mol% with respect to the total number of moles of all monomers, and this was added at 75 ° C. for about 12 hours. Heated. Thereafter, the reaction solution was poured into a large amount of methanol and precipitated to obtain a copolymer.
The obtained copolymer and 3.0 mass times acetonitrile with respect to the copolymer mass were charged, and then 10 mol to the total number of moles of all monomers before copolymerization of 4-dimethylaminopyridine. %, And heated to reflux for 20 hours. After cooling, the reaction solution was neutralized with glacial acetic acid and poured into a large amount of water to cause precipitation. The precipitated polymer was filtered off and dissolved in acetone. Thereafter, the operation of pouring into a large amount of water and precipitating was repeated three times for purification, and a copolymer having a weight average molecular weight of about 6600 was obtained in a yield of 41%. This copolymer was designated as resin B7.

Reference Example 9: [Synthesis of Resin (B8)]
Resin B8 having the following structural units was synthesized according to Polymer Synthesis Example 2 described in JP-A-2006-178317.

Synthesis of Resin H1 Resin H1 having the following structural units was synthesized according to Polymer Synthesis Example 2 described in JP-A-2006-178317.

Examples and Comparative Examples As shown in Table 1, a chemically amplified photoresist composition was prepared by filtering a mixture obtained by mixing and dissolving the following components with a fluororesin filter having a pore size of 0.2 μm. A product was prepared.

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

(Electron beam evaluation)
A silicon wafer was treated on a direct hot plate with hexamethyldisilazane at 90 ° C. for 60 seconds, and the resist solution was spin-coated so that the film thickness after drying was 0.06 μm. After application of the resist solution, pre-baking was performed for 60 seconds at a temperature shown in Table 1 on a direct hot plate.
Each wafer on which a resist film is formed in this manner 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.
The exposure was performed by post-exposure baking on the hot plate at the temperature shown in Table 1 for 60 seconds, and further paddle development for 60 seconds with a 2.38 wt% tetramethylammonium hydroxide aqueous solution.
The developed pattern on the silicon substrate was observed with a scanning electron microscope. The results are shown in Table 2. Effective sensitivity: An exposure amount at which a line and space pattern of 80 nm is 1: 1 is shown.

Resolution evaluation: Observe the pattern when exposed with an exposure amount of effective sensitivity with a scanning electron microscope, ○ that resolves 80 nm, not resolved or resolved, but the top is round The case where there was a tailing or the pattern collapse was observed was evaluated as x.
Pattern shape: The resist pattern after the lithography process was observed with a scanning electron microscope, and it was judged as ○ when the bottom of the pattern had a good slash and was close to a rectangular shape without skirting, and when it was close to a trapezoid with skirting. .

(EUV evaluation)
The silicon wafer was treated on a direct hot plate with hexamethyldisilazane at 90 ° C. for 60 seconds, and then the resist solution was spin-coated so that the film thickness after drying was 0.05 μm. After application of the resist solution, pre-baking was performed for 60 seconds at a temperature shown in Table 1 on a direct hot plate.
Each wafer on which the resist film was formed in this way 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 the temperature shown in Table 1 on a hot plate, and paddle development was further performed for 60 seconds with a 2.38 wt% tetramethylammonium hydroxide aqueous solution.
The developed pattern on the silicon substrate was observed with a scanning electron microscope. The results are shown in Table 3. Effective sensitivity: The exposure amount at which the line and space pattern of 50 nm is 1: 1 is shown.

Resolution evaluation: Observe the pattern when exposed with the exposure amount of effective sensitivity with a scanning electron microscope, ○ if it resolves 50 nm, not resolved or resolved, but the top is round The case where there was a tailing or the pattern collapse was observed was evaluated as x.
Pattern shape: The resist pattern after the lithography process was observed with a scanning electron microscope, and it was judged as ○ when the bottom of the pattern had a good slash and was close to a rectangular shape without skirting, and when it was close to a trapezoid with skirting. .

In addition, the acid generator A1 of Examples 9, 12, and 18 is replaced with A2, and resist compositions are prepared in the same manner as in these Examples, and the same evaluation is performed.
As a result, the same effects as those of Examples 9, 12, and 18 are obtained.
Moreover, the acid generator A1 of Examples 9, 12 and 18 is replaced with A3, and a resist composition is prepared in the same manner as in these Examples, and the same evaluation is performed.
As a result, the same effects as those of Examples 9, 12, and 18 are obtained.

  According to the salt of the present invention, a pattern having excellent resolution and shape can be formed using a resist composition containing a polymer having a repeating unit derived from the salt.

Claims (9)

A structural unit derived from a salt represented by the formula (IB) ;
A polymer having a structural unit derived from a styrene monomer.
[In the formula (IB),
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 divalent aliphatic hydrocarbon group having 1 to 36 carbon atoms, a divalent alicyclic hydrocarbon group having 3 to 36 carbon atoms, or a divalent group having 6 to 36 carbon atoms. The aliphatic hydrocarbon group, the alicyclic hydrocarbon group and the aromatic hydrocarbon group may have a substituent, and the aliphatic hydrocarbon group, alicyclic The methylene group contained in the hydrocarbon group and the aromatic hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
Y ^A represents a vinyl group, acryloyl group, methacryloyl group, acryloyloxy group or methacryloyloxy group which may have a substituent.
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. However, R ^{e1 to} R ^{e13 do not} include a vinyl group, an acryloyl group, a methacryloyl group, an acryloyloxy group, or a methacryloyloxy group.
Z represents a single bond or a divalent linking group. ] The polymer according to claim 1, wherein Z of the salt represented by the formula (IB) is a single bond. X ¹ salt of the formula (I-B) _{are, -CO-O- [CH 2]} h - (h is an integer of 0) polymer according to claim 1 or 2 wherein the . The polymer according to any one of claims 1 to 3, wherein Y ^{1 of the} salt represented by the formula (IB) is 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. ] The polymer according to any one of claims 1 to 4, further comprising a repeating unit derived from a monomer that is insoluble or hardly soluble in an aqueous alkali solution and that can be dissolved in the aqueous alkali solution by the action of an acid. Photoresist composition comprising a polymer and an acid generator according to any one of claims 1 to 5. Acid generator is of the formula (I-B) is an acid generator containing a salt represented by the claims 6 off photoresists composition.

[In the formula (IB),
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 divalent aliphatic hydrocarbon group having 1 to 36 carbon atoms, a divalent alicyclic hydrocarbon group having 3 to 36 carbon atoms, or a divalent group having 6 to 36 carbon atoms. The aliphatic hydrocarbon group, the alicyclic hydrocarbon group and the aromatic hydrocarbon group may have a substituent, and the aliphatic hydrocarbon group, alicyclic The methylene group contained in the hydrocarbon group and the aromatic hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
Y ^A represents a vinyl group, acryloyl group, methacryloyl group, acryloyloxy group or methacryloyloxy group which may have a substituent.
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. However, R ^{e1 to} R ^{e13 do not} include a vinyl group, an acryloyl group, a methacryloyl group, an acryloyloxy group, or a methacryloyloxy group.
Z represents a single bond or a divalent linking group. ] Furthermore, the photoresist composition of Claim 6 or 7 containing a basic compound. (1) The process of apply | coating the photoresist composition in any one of Claims 6-8 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 step of heating the composition layer after exposure,
(5) A method for producing a pattern comprising a step of developing the heated composition layer using a developing device.