JP4553687B2 - Ketene, aldehyde copolymer and resin composition containing the same - Google Patents

Description

  The present invention relates to a copolymer suitable for a resist composition used in the production of semiconductor elements and the like and a resin composition containing the copolymer, and more particularly, far ultraviolet rays having an exposure energy of 300 nm or less, such as KrF excimer. The present invention relates to a copolymer suitable for a resist composition useful for forming a positive pattern using laser light (248 nm) or an electron beam, and a resin composition containing the copolymer. Further, the present invention relates to a copolymer suitable for a resin composition or the like having a certain degree of stability but capable of being easily removed by being cleaved by an acid, decomposed to a low molecular weight, and a resin composition containing the same.

As resist compositions used in the production of semiconductor elements and the like, for example, ketene and aldehyde copolymers are known. (See Patent Document 1)
International Publication No. 03/069412

However, although the exemplified copolymer is decomposed into a low molecular weight compound by an acid, and the decomposed low molecular weight compound is volatilized during post-baking, it is excellent for dry etching. Had a problem.
An object of the present invention is to provide a copolymer that can be applied to alkali development and can be finely processed as compared with a conventional chemically amplified resist.

  As a result of diligent studies to solve the above problems, the present inventors have found that in a structural portion derived from an aldehyde of a polymer having an ester bond in the main chain, which can be easily synthesized from ketene and an aromatic aldehyde, In order to complete the present invention, it has been found that the above-mentioned problems can be solved by making a resist composition as a polymer component by making a copolymer of repeating units having different substituent positions on the aromatic ring. It came.

That is, the present invention
(1) Formula (I)

(Wherein R ₁ and R ₂ are each independently a hydrogen atom, a halogen atom, a C1-C20 hydrocarbon group, a heterocyclic group, a cyano group, a nitro group, a C (═O) R ₄ group, S (O ) _N R ₄ group, P (═O) (R ₄ ) ₂ group, M (R ₄ ) ₃ group, R ₄ is a C1-C20 hydrocarbon oxy group, C1-C20 hydrocarbon group, C1- C20 represents a hydrocarbon thio group of C20, mono- or di-C1-C20 hydrocarbon amino group, M represents a silicon atom, a germanium atom, a tin atom, or a lead atom, and n represents any of 0, 1, or 2. R ₃ represents the formula (IIA)

(In the formula, R ₅ represents a hydrogen atom or a group capable of decomposing / eliminating with an acid, R ₆ represents a halogen atom or a C1 to C20 hydrocarbon group, and m represents an integer of 1 to 3. P represents an integer of 0 or 1 to 3 and represents m + p ≦ 5. When m is 2 or more, R ₅ may be the same or different, and when p is 2 or more, R 5 ₆ may be the same or different, and the OR ₅ substitution position is at least one or more positions selected from the para position and the ortho position of the main chain bonding position. IIB)

(In the formula, R ₁₅₁ represents a hydrogen atom or a group capable of decomposing / eliminating with an acid, R ₁₆₁ represents a halogen atom or a C1 to C20 hydrocarbon group, m1 represents 1 or 2, and p1 represents 0. Or any one of 1 to 3, m1 + p1 ≦ 5, and when m1 is 2, R ₁₅₁ may be the same or different, and when p1 is 2 or more, R ₆₁ is the same or different. And the OR ₁₅₁ substitution position is the meta position of the main chain binding position.). ) With a repeating unit represented by
(2) In the repeating unit represented by the formula (I), R ₁ and R ₂ each independently represent a C1-C20 hydrocarbon group, the copolymer according to (1),
(3) The copolymer according to (1) or (2), wherein the polymer having a repeating unit represented by formula (I) has a number average molecular weight of 2,000 to 50,000. ,
(4) The ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the polymer having a repeating unit represented by the formula (I) is in the range of 1.01 to 3.00. It is related with the copolymer in any one of (1)-(3) characterized by the above-mentioned.

(5) An acid-decomposable composition comprising the copolymer according to any one of (1) to (4) and an acid or a compound that generates an acid by an external stimulus,
(6) The acid-decomposable composition according to (5), wherein the external stimulus is one or more selected from the group consisting of heat, pressure, and radiation sensitivity,
(7) The acid-decomposable composition as described in (5), wherein the compound that generates an acid by external stimulation is a photosensitive compound that generates an acid by radiation-sensitive irradiation.

  (8) Formula (I)

(Wherein R ₁ and R ₂ are each independently a hydrogen atom, a halogen atom, a C1-C20 hydrocarbon group, a heterocyclic group, a cyano group, a nitro group, a C (═O) R ₄ group, S (O ) _N R ₄ group, P (═O) (R ₄ ) ₂ group, M (R ₄ ) ₃ group, R ₄ is a C1-C20 hydrocarbon oxy group, C1-C20 hydrocarbon group, C1- C20 represents a hydrocarbon thio group of C20, mono- or di-C1-C20 hydrocarbon amino group, M represents a silicon atom, a germanium atom, a tin atom, or a lead atom, and n represents any of 0, 1, or 2. R ₃ represents the formula (IIA)

(In the formula, R ₅ represents a hydrogen atom or a group capable of decomposing / eliminating with an acid, R ₆ represents a halogen atom or a C1 to C20 hydrocarbon group, and m represents an integer of 1 to 3. P represents an integer of 0 or 1 to 3 and represents m + p ≦ 5. When m is 2 or more, R ₅ may be the same or different, and when p is 2 or more, R 5 ₆ may be the same or different, and the OR ₅ substitution position is at least one or more positions selected from the para position and the ortho position of the main chain bonding position. IIB)

(In the formula, R ₁₅₁ represents a hydrogen atom or a group capable of decomposing / eliminating with an acid, R ₁₆₁ represents a halogen atom or a C1 to C20 hydrocarbon group, m1 represents 1 or 2, and p1 represents 0. Or any one of 1 to 3, m1 + p1 ≦ 5, and when m1 is 2, R ₁₅₁ may be the same or different, and when p1 is 2 or more, R ₁₆₁ is the same or different. And the OR ₁₅₁ substitution position is the meta position of the main chain binding position.). A photoresist composition comprising a copolymer having a repeating unit represented by:
(9) A photoresist composition comprising the acid-decomposable composition according to any one of (5) to (7),
(10) The photoresist composition according to (8) or (9), further comprising a solvent,
(11) The photoresist composition according to any one of (8) to (10), further comprising a basic compound,
(12) In the repeating unit represented by the formula (I), R ₁ and R ₂ each independently represent a C1 to C20 hydrocarbon group. The photoresist composition as described,
(13) The polymer having a repeating unit represented by formula (I) has a number average molecular weight of 2,000 to 50,000, according to any one of (8) to (12) A photoresist composition,
(14) The ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the polymer having a repeating unit represented by the formula (I) is in the range of 1.01 to 3.00. It is related with the photoresist composition in any one of (8)-(13) characterized by the above-mentioned.

  (15) Formula (IA)

(Wherein R ₁₁ and R ₁₂ are each independently a hydrogen atom, a halogen atom, a C1 to C20 hydrocarbon group, a heterocyclic group, a cyano group, a nitro group, a C (═O) R ₄ group, S (O ) _N R ₄ group, P (═O) (R ₄ ) ₂ group, M (R ₄ ) ₃ group, R ₄ is a C1-C20 hydrocarbon oxy group, C1-C20 hydrocarbon group, C1- C20 represents a hydrocarbon thio group of C20, mono- or di-C1-C20 hydrocarbon amino group, M represents a silicon atom, a germanium atom, a tin atom, or a lead atom, and n represents any of 0, 1, or 2. R ₃₁₁ represents the formula (IIC)

(Wherein R ₁₁₅₁ represents a hydrogen atom or a group capable of decomposing / eliminating with an acid, R ₁₁₆₁ represents a halogen atom or a C1 to C20 hydrocarbon group, m11 represents 1 or 2, and p11 represents 0. Or any integer of 1 to 3, m11 + p11 ≦ 5, when m11 is 2, R ₁₁₅₁ may be the same or different, and when p11 is 2 or more, R ₁₁₆₁ is the same or different. And the OR ₁₅₁ substitution position is the meta position of the main chain binding position.). ) With a repeating unit represented by
(16) In the repeating unit represented by the formula (IA), R ₁₁ and R ₁₂ each independently represent a C1 to C20 hydrocarbon group,
(17) The copolymer according to (15) or (16), wherein the polymer having a repeating unit represented by the formula (IA) has a number average molecular weight of 2,000 to 50,000. ,
(18) The ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the polymer having a repeating unit represented by the formula (IA) is in the range of 1.01 to 3.00. It is related with the copolymer in any one of (15)-(17) characterized by the above-mentioned.

  As described above, the ketene, aldehyde copolymer of the present invention and the composition containing the ketene, the molecular weight of such a size that the main chain of the copolymer is sensitively cleaved by an acid and does not volatilize even during post-baking. As a result, it is possible to decompose the molecular properties of the composition after decomposition, compared to before decomposition, it is possible to develop with alkali, and it is useful as a resin component for semiconductor resists. The possibility is high.

In the repeating unit represented by the formula (I) used in the present invention, R ₁ and R ₂ are each independently a hydrogen atom, a halogen atom, a C1-C20 hydrocarbon group, a heterocyclic group, a cyano group, or a nitro group. , C (═O) R ₄ group, S (O) _n R ₄ group, P (═O) (R ₄ ) ₂ group, M (R ₄ ) ₃ group, and R ₄ is a C1-C20 hydrocarbon. Represents an oxy group, a C1-C20 hydrocarbon group, a C1-C20 hydrocarbon thio group, a mono- or di-C1-C20 hydrocarbon-substituted amino group, and M represents a silicon atom, a germanium atom, a tin atom, or a lead atom. N represents 0, 1, or 2. Specific examples of R ₁ and R ₂ include a hydrogen atom, a fluorine atom, a chloro atom, a bromine atom, a halogen atom that is an iodine atom, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, t -Butyl group, s-butyl group, isobutyl group, n-pentyl group, s-pentyl group, isopentyl group, neopentyl group, n-hexyl group, s-hexyl group, 1,1-dimethyl-n-hexyl group, n -C2-C20 such as C1-C20 alkyl group such as heptyl group, n-decyl group, n-dodecyl group, vinyl group, allyl group, 2-butenyl group, 1-methyl-2-propenyl group, 4-octenyl group C2-C20 alkynyl group such as alkynyl group, ethynyl group, propargyl group, 1-methyl-propynyl group, cyclopropyl group, cyclobutyl group, cyclopentyl group, 1 C3-C20 alicyclic hydrocarbon group such as methylcyclopentyl group, 1-methylcyclohexyl group, 1-adamantyl group, 1-methyladamantyl group, 2-adamantyl group, 2-methyl-2-adamantyl group, norbornyl group, C6-C20 aromatic hydrocarbon group such as phenyl group, 1-naphthyl group, 9-anthracenyl group, 2-pyridyl group, 3-pyridyl group, 4-pyridyl group, 2-furanyl group, 2-thienyl group, 3 -Thienyl group, 1-pyrrolo group, 2-oxazolyl group, 3-isoxazolyl group, 2-thiazolyl group, 3-isothiazolyl group, 1-pyrazolyl group, 4-pyrazolyl group, 2-imidazolyl group, 1,3,4 Oxadiazol-2-yl, 1,2,4-oxadiazol-5-yl, 1,3,4-thiadiazol-2-yl, 1,2,4-thi Asiazol-5-yl, 1,3,4-triazol-2-yl, 1,2,3-thiadiazol-5-yl, 1,2,3-triazol-4-yl, 1,2,3,4 -Tetrazol-5-yl, pyrimidin-2-yl, pyrimidin-4-yl, pyrazin-2-yl, pyridazin-3-yl, 1,2,4-triazin-6-yl, 1,3,5-triazine -2-yl, 1-pyrrolidinyl group, 1-piperidyl group, 4-morpholinyl group, 2-tetrahydrofuranyl group, 4-tetrahydropyranyl group and other heterocyclic groups, methoxycarbonyl group, ethoxycarbonyl group, n-propoxycarbonyl Group, isopropoxycarbonyl group, n-butoxycarbonyl group, C1-C20 alkoxycarbonyl group such as t-butoxycarbonyl group, methylthiocarbonyl C1-C20 alkylthiocarbonyl group such as a group, substituted or unsubstituted carbamoyl group such as N, N-dimethylcarbamoyl group, methylsulfenyl group, phenylsulfenyl group, methylsulfinyl group, phenylsulfenyl group, methylsulfonyl group, phenyl Sulfonyl group, methylsulfuryl group, substituted or unsubstituted sulfamoyl group such as N, N-dimethylsulfamoyl group, dimethylphosphonyl group, bismethylthiophosphonyl group, phosphonyl group such as tetramethylaminophosphonyl group, trimethylsilyl group, Examples thereof include t-butyldimethylsilyl group, phenyldimethylsilyl group, trimethylstannyl group, triphenylplanbanyl group and the like. In particular, a C1-C20 hydrocarbon group can be illustrated preferably.

Each of the substituents of R ₁ and R ₂ shown above can further have a substituent at an appropriate carbon position. As the substituent, fluorine atom, chloro atom, bromine atom, halogen atom which is iodine atom, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, t-butyl group, n-hexyl group , Fluoromethyl group, difluoromethyl group, trifluoromethyl group, perfluoroethyl group, cyclopropyl group, cyclohexyl group, vinyl group, allyl group, phenyl group, 4-chlorophenyl group, 4-methoxyphenyl group, 3,4-dimethylphenyl Substituted phenyl groups such as groups, propargyl group, 2-hydroxy-1,1,1,3,3,3-hexafluoro-2-propyl group, 2- (ethoxymethoxy) -1,1,1,3,3 , Hydrocarbon groups such as 3-hexafluoro-2-propyl group, methoxy group, ethoxy group, n-propoxy group, isopropoxy group, -Butoxy group, s-butoxy group, isobutoxy group, t-butoxy group, fluoromethoxy group, difluoromethoxy group, trifluoromethoxy group, phenoxy group, 4-chlorophenoxy group, benzyloxy group, phenethyloxy group, t-butoxycarbonyl Alkoxy groups such as oxy group, tetrahydropyranyloxy group, phenoxyethoxy group, ethoxyethoxy group, trimethylsilyloxy group, t-butoxycarbonylmethoxy group, amino group, methylamino group, dimethylamino group, t-butoxycarbonylamino group, etc. Amino group, methylthio group, phenylthio group, 2-pyridylthio group, methylsulfinyl group, methylsulfonyl group and other alkyl, aryl, or heterocyclic thio groups or oxidized forms thereof, methoxycarbonyl group, ethoxycarbonyl C2-C20 alkoxycarbonyl groups such as n-propoxycarbonyl group, isopropoxycarbonyl group, n-butoxycarbonyl group and t-butoxycarbonyl group, C2 such as acetyl group, propanoyl group, benzoyl group and 2-pyridylcarbonyl group A C20 acyl group, a cyano group, a nitro group, etc. can be illustrated.

Specific examples of R ₁ and R ₂ having these substituents include chloromethyl group, fluoromethyl group, bromomethyl group, dichloromethyl group, difluoromethyl group, dibromomethyl group, trichloromethyl group, trifluoromethyl group, tribromo Methyl group, trichloromethyl group, 2,2,2-trifluoroethyl group, pentafluoroethyl group, 3,3,3-trifluoropropyl group, 1,1,2,3,3,3-hexafluoropropyl group Haloalkyl groups such as tetrafluoroethenyl group, haloalkenyl groups such as 2,2-difluoroethenyl group, alkoxyalkyl groups such as methoxymethyl group, methoxyethyl group and phenoxymethyl, alkylthio such as methylthiomethyl group and phenylthiomethyl group Alkyl group or arylthioalkyl group, benzyl group, diphenyl Rumechiru group, trityl group, aralkyl groups such as phenethyl group, benzoyl methyl group, an acyl group such as acetyl group, there can be exemplified a cyanomethyl group.

R ₃ represents a substituent represented by formula (IIA) or formula (IIB). In the substituent represented by the formula (IIA), R ₅ represents a hydrogen atom or an acid leaving / decomposing group, m represents an integer of 1 to 3, and when m is 2 or more, R ₅ May be the same or different. Here, the acid leaving / decomposing group means a group capable of leaving and / or decomposing by an acid. Specifically, methoxymethyl group, 2-methoxyethoxymethyl group, bis (2-chloroethoxy) methyl group, tetrahydropyranyl group, 4-methoxytetrahydropyranyl group, tetrahydrofuranyl group, triphenylmethyl group, trimethylsilyl group , 2- (trimethylsilyl) ethoxymethyl group, t-butyldimethylsilyl group, trimethylsilylmethyl group, or a substituent as shown in the following formula.

(Wherein k represents 0 or 1). Furthermore, the following formula

Wherein R ₁₄ represents a C1-C20 unsubstituted or alkoxy-substituted alkyl group, a C5-C10 cycloalkyl group, or a C6-C20 unsubstituted or alkoxy-substituted aryl group, and R ₁₅ represents hydrogen or A C1-C3 alkyl group, and R ₁₆ represents a hydrogen, a C1-C6 alkyl group, or a C1-C6 alkoxy group). Specific examples include 1-methoxyethyl group, 1-ethoxyethyl group, 1-methoxypropyl group, 1-methyl-1-methoxyethyl group, 1- (isopropoxy) ethyl group and the like. The substitution position of the OR ₅ group is at least one position selected from the ortho position and the para position with respect to the main chain bonding position. That is, when the main chain bonding position is the 1-position, any of 2-position substitution, 4-position substitution, 2,6-position di-substitution, 2,4-position di-substitution, 2,4,6-position tri-substitution Represents.

R ₆ represents a halogen atom or a C1-C20 hydrocarbon group. Specifically, among the substituents exemplified for R ₁ and R ₂ , the same substituents as the corresponding examples may be exemplified. The substitution position is not particularly limited. p represents an integer of 0 or 1 to 3, and has a relationship of m + p ≦ 5. When p is 2 or more, R ₆ may be the same or different.

  Specific examples of the substituent represented by the formula (IIA) include 4-hydroxyphenyl group, 4-hydroxy-3-methylphenyl group, 4-t-butoxyphenyl group, 4-tetrahydropyranyloxyphenyl group, 4 -Phenoxyethoxyphenyl group, 4-trimethylsilyloxyphenyl group, 4-t-butoxycarbonyloxyphenyl group, 4-t-butoxycarbonylmethoxyphenyl group, 2,3-difluoro-4-hydroxyphenyl group, 2,3-difluoro -4-t-butoxyphenyl group, 2,6-difluoro-4-hydroxyphenyl group, 2,6-difluoro-4-t-butoxyphenyl group, 3,5-difluoro-4-hydroxyphenyl group, 3,5 -Difluoro-4-t-butoxyphenyl group, 2,3,5,6-tetrafluoro-4-hydro Siphenyl group, 2,3,5,6-tetrafluoro-4-t-butoxyphenyl group, 2-trifluoromethyl-4-hydroxyphenyl group, 2-trifluoromethyl-4-t-butoxyphenyl group, 2- Trifluoromethyl-6-fluoro-4-hydroxyphenyl group, 2-trifluoromethyl-6-fluoro-4-t-butoxyphenyl group, 3-trifluoromethyl-5-fluoro-4-hydroxyphenyl group, 3- Trifluoromethyl-5-fluoro-4-t-butoxyphenyl group, 4- (1-ethoxyethoxy) phenyl group, 4- (2-hydroxy-1,1,1,3,3,3-hexafluoro-2 -Propyl) phenyl group, 4- (2-ethoxymethoxy-1,1,1,3,3,3-hexafluoro-2-propyl) phenyl group, Roxyphenyl group, 2-hydroxy-3-methylphenyl group, 2-t-butoxyphenyl group, 2-tetrahydropyranyloxyphenyl group, 2-phenoxyethoxyphenyl group, 2-trimethylsilyloxyphenyl group, 2-t-butoxy Carbonyloxyphenyl group, 2-t-butoxycarbonylmethoxyphenyl group, 3,4-difluoro-2-hydroxyphenyl group, 3,4-difluoro-2-t-butoxyphenyl group, 4,6-difluoro-2-hydroxy Phenyl group, 4,6-difluoro-2-t-butoxyphenyl group, 3,5-difluoro-2-hydroxyphenyl group, 3,5-difluoro-2-t-butoxyphenyl group, 3,4,5,6 -Tetrafluoro-2-hydroxyphenyl group, 3,4,5,6-tetrafluoro-2-t -Butoxyphenyl group, 4-trifluoromethyl-2-hydroxyphenyl group, 4-trifluoromethyl-2-t-butoxyphenyl group, 4-trifluoromethyl-6-fluoro-2-hydroxyphenyl group, 4-trimethyl Fluoromethyl-6-fluoro-2-t-butoxyphenyl group, 3-trifluoromethyl-5-fluoro-2-hydroxyphenyl group, 3-trifluoromethyl-5-fluoro-2-t-butoxyphenyl group, 2 -(1-ethoxyethoxy) phenyl group, 2- (2-hydroxy-1,1,1,3,3,3-hexafluoro-2-propyl) phenyl group, 2- (2-ethoxymethoxy-1,1 , 1,3,3,3-hexafluoro-2-propyl) phenyl group, 2,4-di-hydroxyphenyl group, 2,4-di-hydroxy-3 Methylphenyl group, 2,4-di-t-butoxyphenyl group, 2,4-di-tetrahydropyranyloxyphenyl group, 2,4-di-phenoxyethoxyphenyl group, 2,4-di-trimethylsilyloxyphenyl group 2,4-di-t-butoxycarbonyloxyphenyl group, 2,4-di-t-butoxycarbonylmethoxyphenyl group, 3-fluoro-2,4-di-hydroxyphenyl group, 3-fluoro-2,4 -Di-t-butoxyphenyl group, 6-fluoro-2,4-di-hydroxyphenyl group, 6-fluoro-2,4-di-t-butoxyphenyl group, 3,5-difluoro-2,4-di -Hydroxyphenyl group, 3,5-difluoro-2,4-di-t-butoxyphenyl group, 6-trifluoromethyl-2,4-di-hydroxyphenyl group, 6 Trifluoromethyl-2,4-di-t-butoxyphenyl group, 3-trifluoromethyl-6-fluoro-2,4-di-hydroxyphenyl group, 3-trifluoromethyl-6-fluoro-2,4- Di-t-butoxyphenyl group, 3-trifluoromethyl-5-fluoro-2,4-di-hydroxyphenyl group, 3-trifluoromethyl-5-fluoro-2,4-di-t-butoxyphenyl group, 2,4-di- (1-ethoxyethoxy) phenyl group, 2,4-di- (2-hydroxy-1,1,1,3,3,3-hexafluoro-2-propyl) phenyl group, 2, A 4-di- (2-ethoxymethoxy-1,1,1,3,3,3-hexafluoro-2-propyl) phenyl group and the like can be exemplified.

In the substituent represented by the formula (IIB), R ₁₅₁ represents a hydrogen atom or an acid leaving / decomposing group, m1 represents 1 or 2, and when m is 2, R ₅₁ is the same or different. It may be. Specific examples of R ₁₅₁ include the same specific examples as those exemplified for R ₅ . The substitution position of the OR ₁₅₁ group is the meta position with respect to the main chain bonding position. That is, when the main chain bond position is the 1st position, it represents either 3-position substitution or 3,5-disubstitution.

R ₁₆₁ represents a halogen atom or a C1-C20 hydrocarbon group. Specifically, among the substituents exemplified for R ₁ and R ₂ , the same substituents as the corresponding examples may be exemplified. The substitution position is not particularly limited. p1 represents an integer of 0 or 1 to 3, and has a relationship of m1 + p1 ≦ 5. When p1 is 2 or more, R ₁₆₁ may be the same or different.

  Specific examples of the substituent represented by the formula (IIIB) include 3-hydroxyphenyl group, 3-hydroxy-3-methylphenyl group, 3-t-butoxyphenyl group, 3-tetrahydropyranyloxyphenyl group, 3 -Phenoxyethoxyphenyl group, 3-trimethylsilyloxyphenyl group, 3-t-butoxycarbonyloxyphenyl group, 3-t-butoxycarbonylmethoxyphenyl group, 2,4-difluoro-3-hydroxyphenyl group, 2,4-difluoro -3-t-butoxyphenyl group, 2,6-difluoro-3-hydroxyphenyl group, 2,6-difluoro-3-t-butoxyphenyl group, 4,5-difluoro-3-hydroxyphenyl group, 4,5 -Difluoro-3-t-butoxyphenyl group, 2,4,5,6-tetrafluoro-3-hydride Xyphenyl group, 2,4,5,6-tetrafluoro-3-t-butoxyphenyl group, 2-trifluoromethyl-3-hydroxyphenyl group, 2-trifluoromethyl-3-t-butoxyphenyl group, 2- Trifluoromethyl-6-fluoro-3-hydroxyphenyl group, 2-trifluoromethyl-6-fluoro-3-t-butoxyphenyl group, 4-trifluoromethyl-5-fluoro-3-hydroxyphenyl group, 4- Trifluoromethyl-5-fluoro-3-t-butoxyphenyl group, 3- (1-ethoxyethoxy) phenyl group, 3- (2-hydroxy-1,1,1,3,3,3-hexafluoro-2 -Propyl) phenyl group, 3- (2-ethoxymethoxy-1,1,1,3,3,3-hexafluoro-2-propyl) phenyl group, 3, -Di-hydroxyphenyl group, 3,5-di-hydroxy-3-methylphenyl group, 3,5-di-t-butoxyphenyl group, 3,5-di-tetrahydropyranyloxyphenyl group, 3,5- Di-phenoxyethoxyphenyl group, 3,5-di-trimethylsilyloxyphenyl group, 3,5-di-t-butoxycarbonyloxyphenyl group, 3,5-di-t-butoxycarbonylmethoxyphenyl group, 4-fluoro- 3,5-di-hydroxyphenyl group, 4-fluoro-3,5-di-t-butoxyphenyl group, 6-fluoro-3,5-di-hydroxyphenyl group, 6-fluoro-3,5-di- t-butoxyphenyl group, 4,6-difluoro-3,5-di-hydroxyphenyl group, 4,6-difluoro-3,5-di-t-butoxyphenyl group, Trifluoromethyl-3,5-di-hydroxyphenyl group, 6-trifluoromethyl-3,5-di-t-butoxyphenyl group, 4-trifluoromethyl-6-fluoro-3,5-di-hydroxyphenyl group Group, 4-trifluoromethyl-6-fluoro-3,5-di-t-butoxyphenyl group, 4-trifluoromethyl-6-fluoro-3,5-di-hydroxyphenyl group, 4-trifluoromethyl- 6-fluoro-3,5-di-t-butoxyphenyl group, 3,5-di- (1-ethoxyethoxy) phenyl group, 3,5-di- (2-hydroxy-1,1,1,3, 3,3-hexafluoro-2-propyl) phenyl group, 3,5-di- (2-ethoxymethoxy-1,1,1,3,3,3-hexafluoro-2-propyl) phenyl group, etc. To do Kill.

The substituents represented by the formula (IIA) or the formula (IIB) shown above can be preferably exemplified as the substituents for R ₁ and R ₂ .
In addition, the substituents represented by R _{1 to} R ₃ do not have to be the same in all the repeating units represented by the formula (I), and two or more kinds can be appropriately mixed and used. For example, as R ₃ , a p-methoxyphenyl group and a p- (1-ethoxyethoxy) phenyl group can be mixed at a molar ratio of 1/99 to 99/1. The molar ratio ((IIA) / (IIB)) of the repeating unit having a substituent represented by the formula (IIA) and the formula (IIB) in the repeating unit represented by the formula (I) is not particularly limited. / 1 to 1/99, preferably 80/20 to 20/80, and more preferably 60/40 to 40/60.

The polymer having a repeating unit represented by the formula (I) in the present invention includes a polymer consisting only of the repeating unit represented by the formula (I), and the repeating unit represented by the formula (I) and the formula (I The polymer which consists of repeating units other than the repeating unit represented by I) is meant.
Specific examples of the repeating unit other than the repeating unit represented by the formula (I) include a repeating unit represented by the formula (III).

In the formula, R ₃₁ , R ₃₂ and R ₃₃ each independently represents a hydrogen atom, a fluorine atom, a C1-20 linear, branched or cyclic alkyl group, or a fluorinated alkyl group, and R ₃₄ Represents a hydroxyl group or a C6-20 aromatic hydrocarbon group optionally substituted with an alkoxy group, or a CO ₂ R ₃₅ group, and R ₃₅ represents a C1 to C20 hydrocarbon group, preferably an acid-free group. Represents a stable group.

In this case, as the linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, A cyclopentyl group, a cyclohexyl group, a 2-ethylhexyl group, an n-octyl group and the like can be exemplified, and those having 1 to 12 carbon atoms, particularly 1 to 10 carbon atoms are preferable. The fluorinated alkyl group is one in which part or all of the hydrogen atoms of the alkyl group are substituted with fluorine atoms, and includes a trifluoromethyl group, a 2,2,2-trifluoroethyl group, 3, Examples include 3,3-trifluoropropyl group and 1,1,2,3,3,3-hexafluoropropyl group.
R ₃₄ is a C6-20 aromatic hydrocarbon group which may be substituted with a hydroxyl group or a hydroxyl group in which a hydrogen atom is substituted, and specifically includes a substituent represented by the following formula (IV) can do.

In the formula, R ₄₀ represents a linear, branched or cyclic alkyl group having 1 to 14 carbon atoms or a fluorinated alkyl group, and specific examples thereof are the same substitutions as the specific examples illustrated for R ₃₁ above. Examples of the group include X, a fluorine atom, and R ₄₁ a C1-C20 hydrocarbon group, preferably an acid labile group. a, b, c, and d each represent an integer of 0 or 1 to 5, and a + b + c + d is any of 0 to 5.

In R ₄₁ , the C1-C20 hydrocarbon group can be exemplified by the same substituents as those exemplified for R ₁ , and various acid labile groups can be selected. Exemplifies groups represented by the following formula (V), (VI), or (VII), trialkylsilyl groups having 1 to 6 carbon atoms, oxoalkyl groups having 4 to 20 carbon atoms, and the like of each alkyl group. be able to.

In the formulas (V) and (VI), R ₅₁ and R ₅₄ are monovalent hydrocarbon groups such as linear, branched or cyclic alkyl groups having 1 to 20 carbon atoms, oxygen atom, sulfur atom, nitrogen atom And may contain a hetero atom such as a fluorine atom.
R ₅₂ and R ₅₃ are a hydrogen atom or a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, and may contain a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom or a fluorine atom. R ₅₂ and R ₅₃ , R ₅₂ and R ₅₄ , and R ₅₃ and R ₅₄ may be bonded to each other to form a ring. h represents 0 or an integer of 1 to 10.
More preferably, R _{51 to} R ₅₄ are the following groups. R ₅₁ is a tertiary alkyl group having 4 to 20 carbon atoms, preferably 4 to 15 carbon atoms, each alkyl group is a trialkylsilyl group having 1 to 6 carbon atoms, an oxoalkyl group having 4 to 20 carbon atoms, or the above formula (VII And a tertiary alkyl group specifically includes a tert-butyl group, a tert-amyl group, a 1,1-diethylpropyl group, a 1-ethylcyclopentyl group, a 1-butylcyclopentyl group, 1- Specific examples of the trialkylsilyl group include an ethylcyclohexyl group, 1-butylcyclohexyl group, 1-ethyl-2-cyclopentenyl group, 1-ethyl-2-cyclohexenyl group, and 2-methyl-2-adamantyl group. Examples include trimethylsilyl group, triethylsilyl group, dimethyl-tert-butylsilyl group and the like. Specifically, the 3-oxo-cyclohexyl group, 4-methyl-2-oxooxan-4-yl group, and 5-methyl-5-oxo-dioxolane-4-yl group.

R ₅₂ and R _{53 each} represent a hydrogen atom or a linear, branched or cyclic alkyl group having 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms, specifically a methyl group, an ethyl group, a propyl group or an isopropyl group. N-butyl group, sec-butyl group, tert-butyl group, cyclopentyl group, cyclohexyl group, 2-ethylhexyl group, n-octyl group and the like. R ₅₄ represents a monovalent hydrocarbon group which may have a hetero atom such as an oxygen atom having 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms, a linear, branched, or cyclic alkyl group, Examples include those in which a part of hydrogen atoms are substituted with a hydroxyl group, an alkoxy group, an oxo group, an amino group, an alkylamino group, and the like. Specifically, a 4-hydroxybutyl group, a 2-butoxyethyl group, 4 Examples thereof include substituted alkyl groups such as -hydroxymethyl-1-cyclohexylmethyl group, 2-hydroxyethoxy-2-ethyl group, 6-hydroxyhexyl group and 1,3-dioxolan-2-one-4-methyl group.

R ₅₂ and R ₅₃ , R ₅₂ and R ₅₄ , R ₅₃ and R ₅₄ may form a ring, and in the case of forming a ring, R ₅₂ , R ₅₃ and R ₅₄ each have 1 to 18 carbon atoms, Preferably it represents 1-10 linear or branched alkylene groups.
Specific examples of the formula (V) include a t-butoxycarbonyl group, a t-butoxycarbonylmethyl group, a t-amyloxycarbonyl group, a t-amyloxycarbonylmethyl group, a 1,1-diethylpropyloxycarbonyl group, 1,1-diethylpropyloxycarbonylmethyl group, 1-ethylcyclopentyloxycarbonyl group, 1-ethylcyclopentyloxycarbonylmethyl group, 1-ethyl-2-cyclopentenyloxycarbonyl group, 1-ethyl-2-cyclopentenyloxycarbonyl Examples thereof include a methyl group, 1-ethoxyethoxycarbonylmethyl group, 2-tetrahydropyranyloxycarbonylmethyl group, 2-tetrahydrofuranyloxycarbonylmethyl group and the like.

  Specific examples of the linear or branched acid labile group represented by the above formula (VI) include methoxymethyl group, ethoxymethyl group, n-propoxymethyl group, n-butoxymethyl group, Isopropoxymethyl group, t-butoxymethyl group, 1-methoxy-ethyl group, 1-ethoxy-ethyl group, 1-methoxy-propyl group, 1-methoxy-butyl group, 1-ethoxy-propyl group, 1-ethoxy- Propyl group, 1-n-propoxyethyl group, 1-n-propoxyethyl group, 1-n-propoxy-propyl group, 1-n-butoxy-butyl group, 1-n-propoxy-butyl group, 1-cyclopentyloxy -Ethyl group, 1-cyclohexyloxy-ethyl group, 2-methoxy-2-propyl group, 2-ethoxy-2-propyl group and the like can be exemplified.

  Among the acid labile groups represented by the above formula (VI), specific examples of the cyclic group include tetrahydrofuran-2-yl group, 2-methyltetrahydrofuran-2-yl group, tetrahydropyran-2-yl group, 2 -A methyltetrahydropyran-2-yl group etc. can be illustrated. As the formula (4), a 1-ethoxy-ethyl group, a 1-n-butoxy-ethyl group, and a 1-ethoxy-n-propyl group are preferable.

In the formula (VII), R ₅₅ , R ₅₆ and R ₅₇ are monovalent hydrocarbon groups such as a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, such as an oxygen atom, a sulfur atom and a nitrogen atom. Hetero atoms, fluorine atoms and the like, and R ₅₅ and R ₅₆ , R ₅₅ and R ₅₇ , and R ₅₆ and R ₅₇ may be bonded to each other to form a ring.
The tertiary alkyl group represented by the formula (VII) includes a t-butyl group, 1,1-diethyl-n-propyl group, 1-ethylnorbornyl group, 1-methylcyclohexyl group, 1-ethylcyclopentyl group, 2 -(2-Methyl) adamantyl group, 2- (2-ethyl) adamantyl group, tert-amyl group and the like can be mentioned.
Moreover, as a tertiary alkyl group represented by a formula (VII), the functional group shown below can be illustrated concretely.

Here, R ₆₁ and R ₆₄ represent a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms, specifically a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, Examples include sec-butyl group, n-pentyl group, n-hexyl group, cyclopropyl group, cyclopropylmethyl group and the like. R ₆₂ is a monovalent hydrocarbon radical such as a hydrogen atom, contain a heteroatom or a monovalent hydrocarbon group having 1 to 6 carbon atoms, or an alkyl group which may through a hetero atom having 1 to 6 carbon atoms. Examples of the hetero atom include an oxygen atom, a sulfur atom, and a nitrogen atom, and —OH, —OR (R is an alkyl group having 1 to 20 carbon atoms, particularly 1 to 16 carbon atoms, the same applies hereinafter), —O—, — S -, - S (= O ) -, - NH 2, -NHR, -NR 2, -NH -, - can contain or intervening as NR-.

_Examples of R ₆₃ include a hydrogen atom, or an alkyl group having 1 to 20 carbon atoms, particularly 1 to 16 carbon atoms, a hydroxyalkyl group, an alkoxyalkyl group, an alkoxy group, or an alkoxyalkyl group. It can be either branched or annular. Specifically, methyl group, hydroxymethyl group, ethyl group, hydroxyethyl group, propyl group, isopropyl group, n-butyl group, sec-butyl group, n-pentyl group, n-hexyl group, methoxy group, methoxymethoxy Group, ethoxy group, tert-butoxy group and the like.

Examples of the trialkylsilyl group in which each alkyl group used as the acid labile group of R ₄₁ has 1 to 6 carbon atoms include a trimethylsilyl group, a triethylsilyl group, and a tert-butyldimethylsilyl group.

Examples of the oxoalkyl group having 4 to 20 carbon atoms used as the acid labile group for R ₄₁ include a 3-oxocyclohexyl group and a group represented by the following formula.

Further, the acid labile group of R ₄₁ may be an acetal bridging group represented by the following formula (VIII) or (IX).

In formula, _R71 , _R72 shows a hydrogen atom or a C1-C8 linear, branched or cyclic alkyl group. Alternatively, R ₇₁ and R ₇₂ may be bonded to form a ring, and when forming a ring, R ₇₁ and R ₇₂ represent a linear or branched alkylene group having 1 to 8 carbon atoms. R ₇₃ is a linear, branched or cyclic alkylene group having 1 to 10 carbon atoms, e is an integer of 1 to 7, and f and g are 0 or an integer of 1 to 10. A represents an (e + 1) -valent aliphatic or alicyclic saturated hydrocarbon group having 1 to 50 carbon atoms, an aromatic hydrocarbon group or a heterocyclic group, and these groups may intervene a hetero atom, Alternatively, a part of hydrogen atoms bonded to the carbon atom may be substituted with a hydroxyl group, a carboxyl group, a carbonyl group, or a fluorine atom. B represents —CO—O—, —NHCO—O— or —NHCONH—.

  Specific examples of the crosslinked acetal represented by the formulas (VIII) and (IX) include those represented by the following formulae.

Specific examples of the repeating unit (III) having a functional group represented by the formula (IV) include a repeating unit obtained by polymerizing the following monomers.
Styrene, α-methylstyrene, chlorostyrene, 1,1-diphenylethylene, stilbene, 4-hydroxystyrene, 4-hydroxy-α-methylstyrene, 4-hydroxy-3-methyl-styrene, 4-t-butoxy-styrene 4-tetrahydropyranyloxy-styrene, 4-phenoxyethoxy-styrene, 4-trimethylsilyloxy-styrene, 4-t-butoxycarbonyloxy-styrene, 4-t-butoxycarbonylmethoxy-styrene, 2,3-difluoro- 4-hydroxystyrene, 2,3-difluoro-4-t-butoxy-styrene, 2,6-difluoro-4-hydroxy-styrene, 2,6-difluoro-4-t-butoxy-styrene, 3,5-difluoro -4-hydroxy-styrene, 3,5-difluoro- 4-t-butoxy-styrene, 2,3,5,6-tetrafluoro-4-hydroxy-styrene, 2,3,5,6-tetrafluoro-4-t-butoxy-styrene, 2-trifluoromethyl- 4-hydroxy-styrene, 2-trifluoromethyl-4-t-butoxy-styrene, 2-trifluoromethyl-6-fluoro-4-hydroxy-styrene, 2-trifluoromethyl-6-fluoro-4-t- Butoxy-styrene, 3-trifluoromethyl-5-fluoro-4-hydroxy-styrene, 3-trifluoromethyl-5-fluoro-4-t-butoxy-styrene, 4- (1-ethoxyethoxy) -styrene, 4 -(2-hydroxy-1,1,1,3,3,3-hexafluoro-2-propyl) -styrene, 4- (2-ethoxymethoxy-1,1,1) 3,3,3-hexafluoro-2-propyl) -styrene, 2,3-difluoro-4-hydroxystyrene, 2,3-difluoro-4-tert-butoxy-α-fluoro-styrene, 2,6-difluoro -4-hydroxy-α-fluoro-styrene, 2,6-difluoro-4-t-butoxy-α-fluoro-styrene, 3,5-difluoro-4-hydroxy-α-fluoro-styrene, 3,5-difluoro -4-t-butoxy-α-fluoro-styrene, 2,3,5,6-tetrafluoro-4-hydroxy-α-fluoro-styrene, 2,3,5,6-tetrafluoro-4-t-butoxy -Α-fluoro-styrene, 2-trifluoromethyl-4-hydroxy-α-fluoro-styrene, 2-trifluoromethyl-4-t-butoxy-α-fluoro- Tylene, 2-trifluoromethyl-6-fluoro-4-hydroxy-α-fluoro-styrene, 2-trifluoromethyl-6-fluoro-4-tert-butoxy-α-fluoro-styrene, 3-trifluoromethyl- 5-fluoro-4-hydroxy-α-fluoro-styrene, 3-trifluoromethyl-5-fluoro-4-t-butoxy-α-fluoro-styrene, 4- (1-ethoxyethoxy) -α-methyl-styrene 4- (2-hydroxy-1,1,1,3,3,3-hexafluoro-2-propyl) -α-fluoro-styrene, 4- (2-ethoxymethoxy-1,1,1,3, 3,3-hexafluoro-2-propyl) -α-fluoro-styrene and the like.

Furthermore, when R ₃₄ is a CO ₂ R ₃₅ group, R ₃₅ can be exemplified by the same substituents as those exemplified for R ₄ . In this case, as a combination of R _{31 to} R _33, a combination as shown in the following formula can be preferably used. (Repeated unit obtained when polymerizing the following compounds.)

Specific examples of the repeating unit having a CO ₂ R ₃₅ group include methyl acrylate, ethyl acrylate, propyl acrylate, amyl acrylate, cyclohexyl acrylate, ethyl hexyl acrylate, octyl acrylate, and tert-octyl acrylate. , Chloroethyl acrylate, 2-ethoxyethyl acrylate, 2,2-dimethyl-3-ethoxypropyl acrylate, 5-ethoxypentyl acrylate, 1-methoxyethyl acrylate, 1-ethoxyethyl acrylate, 1-methoxypropyl acrylate, 1-methyl -1-methoxyethyl acrylate, 1- (isopropoxy) ethyl acrylate, benzyl acrylate, methoxybenzyl acrylate, furfuryl acrylate, tetrahydrofurfuryl acrylate, etc. Acrylic acid esters,
Methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, chlorobenzyl methacrylate, octyl methacrylate, 2-ethoxyethyl methacrylate, 4-methoxybutyl methacrylate, 5-methoxypentyl methacrylate, 2 , 2-dimethyl-3-ethoxypropyl methacrylate, 1-methoxyethyl methacrylate, 1-ethoxyethyl methacrylate, 1-methoxypropyl methacrylate, 1-methyl-1-methoxyethyl methacrylate, 1- (isopropoxy) ethyl methacrylate, furfuryl Methacrylate, tetrahydrofurfuryl methacrylate, etc. Methacrylic acid esters, methyl crotonate, ethyl crotonate, propyl crotonate, amyl crotonate, cyclohexyl crotonate, ethyl hexyl crotonate, octyl crotonate, crotonic acid-t-octyl, chloroethyl crotonate, 2-ethoxyethyl crotonate 2,2-dimethyl-3-ethoxypropyl crotonate, 5-ethoxypentyl crotonate, 1-methoxyethyl crotonate, 1-ethoxyethyl crotonate, 1-methoxypropyl crotonate, 1-methyl-1-methoxy Crotonic acid esters such as ethyl crotonate, 1- (isopropoxy) ethyl crotonate, benzyl crotonate, methoxybenzyl crotonate, furfuryl crotonate, tetrahydrofurfuryl crotonate, etc. Dimethyl citrate, diethyl itaconate, dipropyl itaconate, diamyl itaconate, dicyclohexyl itaconate, bis (ethylhexyl) itaconate, dioctyl itaconate, di-t-octyl itaconate, bis (chloroethyl) itaconate, bis (2- Ethoxyethyl) itaconate, bis (2,2-dimethyl-3-ethoxypropyl) itaconate, bis (5-ethoxypentyl) itaconate, bis (1-methoxyethyl) itaconate, bis (1-ethoxyethyl) itaconate, bis (1 -Methoxypropyl) itaconate, bis (1-methyl-1-methoxyethyl) itaconate, bis (1- (isopropoxy) ethyl) itaconate, dibenzylitaconate, bis (methoxybenzyl) itaconate, diflufuryl Examples thereof include repeating units derived from itaconic acid esters such as taconate and ditetrahydrofurfururitaconate. Furthermore, the repeating unit represented by a following formula can be illustrated.

Furthermore, examples of the repeating unit other than the repeating unit represented by the formula (I) include a compound represented by the formula (X).

In the formula, each of R ₈₁ and R ₈₂ independently represents a hydrogen atom, a halogen atom, a C1-C20 hydrocarbon group, a heterocyclic group, a cyano group, a nitro group, a C (═O) R ₄ group, or S (O ) NR ₄ group, P (═O) (R ₄ ) ₂ group, M (R ₄ ) ₃ group, specifically, the same substituents as those exemplified for R ₁ can be exemplified. .

  The polymer having the repeating unit represented by the formula (I) in the present invention is represented by the polymer consisting only of the repeating unit represented by the formula (I) and the formula (I) as described above. Means a polymer comprising a repeating unit other than the repeating unit represented by formula (I), and the polymerization mode of the repeating unit represented by formula (I) and the other repeating unit is particularly limited. Any of random polymerization, block polymerization, partial block polymerization, and alternating polymerization can be used.

Moreover, the mixing ratio of the repeating unit represented by the formula (I) and the other repeating units is not particularly limited, and can be arbitrarily set in a molar ratio of 99/1 to 1/99.
The number average molecular weight of the polymer having a repeating unit represented by the formula (I) is not particularly limited. However, when used for a resist or the like, in consideration of etching resistance, alkali solubility, etc., 2,000 to 50,000 The range of is preferable. The molecular weight distribution, which is the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn), is not particularly limited, but is in the range of 1.01 to 3.00, 1 A range of .01 to 1.50 is preferred.
As a method for producing a polymer having a repeating unit represented by the formula (I), specifically, an ketene represented by the following formula (XI) and an aldehyde represented by the formula (XII) are converted into an anionic polymerization initiator. A method for anionic polymerization in the presence can be exemplified.

In the formula, R ₉₁ corresponds to R ₁ , R ₉₂ corresponds to R ₂ , and R ₉₃ corresponds to R ₃ , respectively, and a substituent that hinders anionic polymerization, such as a substituent having an active hydrogen atom, The substituent which excluded the substituent etc. which are reactive with an anionic polymerization initiator is represented.
The solvent used for anionic polymerization is not particularly limited as long as it is a polar solvent that does not participate in the polymerization reaction and is compatible with the polymer. Specifically, aliphatic solvents such as n-hexane and n-heptane are used. Hydrocarbons, alicyclic hydrocarbons such as cyclohexane and cyclopentane, aromatic hydrocarbons such as benzene and toluene, ethers such as diethyl ether, tetrahydrofuran (THF) and dioxane, as well as anisole and hexamethyl phosphor The organic solvent normally used in anionic polymerization, such as amide, can be mentioned. Moreover, these solvent can be used individually by 1 type or as a 2 or more types of mixed solvent.

  Examples of the anionic polymerization initiator include alkali metals or organic alkali metals. Examples of the alkali metals include lithium, sodium, potassium, cesium, sodium-potassium alloys, and the like. Alkylated products, allylated products, arylated products and the like of the above alkali metals can be used. Specifically, ethyllithium, n-butyllithium, sec-butyllithium, t-butyllithium, ethylsodium, lithium biphenyl, lithium Naphthalene, lithium triphenyl, sodium naphthalene, potassium naphthalene, α-methylstyrene sodium dianion, 1,1-diphenylhexyl lithium, 1,1-diphenyl-3-methylpentyl lithium, 1,1-diphenylmethyl potassium 1,4-dilithio-2-butene, 1,6-dilithiohexane, polystyryllithium, cumylpotassium, cumylcesium and the like. These compounds may be used alone or in combination of two or more. Can be used.

  In the reaction, compounds represented by the formulas (XI) and (XII) are usually added to an anionic polymerization initiator, and anionic living polymerization is performed. These series of reactions are carried out in the range of −100 to 0 ° C., preferably −70 to −20 ° C. under an inert gas such as argon or nitrogen, or under high vacuum. The molar ratio of the ketene represented by the formula (XI) to be used and the aldehyde represented by the formula (XII) is not particularly limited, but is preferably in the range of 99/1 to 50/50. Further, as described above, the ketene represented by the formula (XI) and the aldehyde represented by the formula (XII) can be used singly or in combination of two or more.

In addition, the compound in which R ₅ is a hydrogen atom can be obtained by polymerizing a compound having a functional group other than a hydrogen atom and removing the functional group. In this case, by controlling the reaction, Only a part of the functional group can be eliminated. For example, the reaction for partially or completely removing the protecting group of the phenolic hydroxyl group that is unstable to acids includes the solvents exemplified in the polymerization reaction, alcohols such as methanol and ethanol, and ketones such as acetone and methyl ethyl ketone. , Polyhydric alcohol derivatives such as methyl cellosolve, ethyl cellosolve, one or more kinds of mixed solvents such as water, hydrochloric acid, sulfuric acid, hydrogen chloride gas, hydrobromic acid, p-toluenesulfonic acid, Trichloroacetic acid, methanesulfonic acid, trifluoromethanesulfonic acid, a general formula XHSO ₄ (wherein X represents an alkali metal such as Li, Na, K, etc.) and an acid reagent such as a bisulfate are usually used as catalysts. It is carried out at a temperature between room temperature and 150 ° C. Further, when a silyl group is used as a protecting group, a fluorine anion compound such as quaternary ammonium fluoride can also be used.

The amount of the acidic reagent to be used is sufficient as the catalyst amount, but usually the average molecular weight of the whole polymer is obtained from the molar fraction of each unit and the molecular weight of each unit, and each of the total weight, average molecular weight, and molar fraction of each polymer is determined. The number of moles of the unit is determined, and is in the range of 0.1 to 3 equivalents, preferably 0.1 to 1 equivalents relative to the number of moles of the alkoxy group (OR ₅ group).

Moreover, another functional group can also be introduce | transduced into the hydroxyl part obtained as mentioned above. The above-described operation has been described by taking the substituent of R ₃ as an example, but it can also be performed on the same substituent as OR ₅ on R ₁ and R ₂ .

  Since the polymer having a repeating unit represented by the formula (I) has a property that the main chain is easily cleaved by an acid as described in the Examples, a compound that generates an acid by an acid or an external stimulus coexists. In the composition to be used, it can be used as an acid-decomposable composition, and particularly preferably used as a resist composition. When used as a resist composition, a polymer used in an existing chemical amplification positive resist can be mixed and used.

  The acid used in the present invention is not particularly limited as long as it is an acidic compound. Specifically, hydrochloric acid, sulfuric acid, phosphoric acid, phosphorus oxychloride, methanesulfonic acid, p-toluenesulfonic acid, p-toluenesulfonic acid, Examples thereof include pyridine salt, chlorosulfonic acid, trichloroacetic acid, benzoic acid and the like.

  In a compound that generates an acid by an external stimulus, specific examples of the external stimulus include heat, pressure, radiation sensitivity, and the like, and particularly when the above composition is used as a resist composition, the radiation sensitivity. A compound that generates an acid upon irradiation (hereinafter abbreviated as “acid generator”) can be preferably used. The polymer and acid generator containing the repeating unit represented by the formula (I) are generally used in a state dissolved in a solvent.

  The acid generator used in the present invention is not limited as long as it is a compound capable of generating an acid upon irradiation with radiation and does not adversely affect the formation of a resist pattern, but particularly has a light transmittance of around 248.4 nm. Is high and can maintain the high transparency of the resist composition, the light transmission is enhanced by exposure to maintain the high transparency of the resist composition, or the acid generation efficiency is high, so the effect is exhibited with a small amount of addition. An acid generator is preferred. Specific examples of particularly preferred acid generators include compounds represented by the following formula (XIII), formula (XVI), formula (XV), formula (XVI) and formula (XVII).

(Wherein R ₁₀₀ and R ₁₀₁ each independently represents a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms, or an aralkyl group, and W represents a sulfonyl group or a carbonyl group.)

(In the formula, R ₁₀₃ and R ₁₀₄ each independently represent a hydrogen atom, a halogen atom or an alkyl group having 1 to 4 carbon atoms, and R ₁₀₅ represents a linear, branched or cyclic group having 1 to 6 carbon atoms. Represents an alkyl group, an aralkyl group, or an optionally substituted phenyl group, and V represents a sulfonyl group or a carbonyl group.)

(Wherein, R _106, R ₁₀₇ and R ₁₀₈ are independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a t- butoxycarbonyl group, R ₁₀₉ Represents a fluorine-containing alkyl group having 1 to 8 carbon atoms, an optionally substituted phenyl group, or a 10-camphor group, Y represents a sulfur atom or an iodine atom, and when Y is an iodine atom, z represents 0. And z represents 1 in the case of a sulfur atom.)

(Wherein R ₁₁₀ represents an alkyl group having 1 to 6 carbon atoms, a fluorine-containing alkyl group having 1 to 8 carbon atoms, an optionally substituted phenyl group, or a 10-camphor group.)

(In the formula, R ₁₁₁ and R ₁₁₂ each independently represent a hydrogen atom, a methyl group, or an ethyl group, and R ₁₁₁ and R ₁₁₂ have an aromatic ring group or a bridged alicyclic hydrocarbon group having an unsaturated bond. R ₁₁₃ represents an alkyl group having 1 to 6 carbon atoms, a fluorine-containing alkyl group having 1 to 8 carbon atoms, an optionally substituted phenyl group, or a 10-camphor group.)

  Specifically, preferred acid generators include those represented by formula (XIII) such as 1-cyclohexylsulfonyl-1- (1,1-dimethylethylsulfonyl) diazomethane, bis (1,1-dimethylethylsulfonyl) ) Diazomethane, bis (1-methylethylsulfonyl) diazomethane, bis (cyclohexylsulfonyl) diazomethane, 1-cyclohexylsulfonyl-1-cyclohexylcarbonyldiazomethane, 1-diazo-1-cyclohexylsulfonyl-3,3-dimethylbutan-2-one 1-diazo-1- (1,1-dimethylethylsulfonyl) -3,3-dimethylbutan-2-one and the like.

  Specific examples of the acid generator represented by the formula (XIV) include bis (p-toluenesulfonyl) diazomethane, bis (2,4-dimethylbenzenesulfonyl) diazomethane, bis (p-tert-butylphenylsulfonyl) diazomethane, bis (P-chlorobenzenesulfonyl) diazomethane, methylsulfonyl-p-toluenesulfonyldiazomethane, cyclohexylsulfonyl-p-toluenesulfonyldiazomethane, 1-p-toluenesulfonyl-1-cyclohexylcarbonyldiazomethane, 1-diazo-1- (p-toluene) Examples include sulfonyl) -3,3-dimethylbutan-2-one and the like.

  Specific examples of the acid generator represented by the formula (XV) include triphenylsulfonium / trifluoromethanesulfonate, triphenylsulfonium / perfluorobutanesulfonate, triphenylsulfonium / perfluorooctanesulfonate, triphenylsulfonium / p-toluenesulfonate. , Triphenylsulfonium · 10-camphorsulfonate, diphenyl-p-tolylsulfonium · trifluoromethanesulfonate, diphenyl-p-tolylsulfonium · perfluorobutanesulfonate, diphenyl-p-tolylsulfonium · perfluorooctanesulfonate, diphenyl-p-tolyl Sulfonium / p-toluenesulfonate, diphenyl-p-tolylsulfonium / 10-camphorsulfonate, di Phenyl-p-tert-butylphenylsulfonium / trifluoromethanesulfonate, diphenyl-p-tert-butylphenylsulfonium / perfluorobutanesulfonate, diphenyl-p-tert-butylphenylsulfonium / perfluorooctanesulfonate, diphenyl-p-tert- Butylphenylsulfonium, p-toluenesulfonate, diphenyl-p-tert-butylphenylsulfonium, 10-camphorsulfonate, diphenyl-p-tert-butylphenylsulfonium, p-fluorobenzenesulfonate, diphenyl-p-cyclohexylphenylsulfonium, trifluoromethane Sulfonate, diphenyl-p-cyclohexylphenylsulfonium perfluorobutans Phonate, diphenyl-p-cyclohexylphenylsulfonium / perfluorooctanesulfonate, diphenyl-p-cyclohexylphenylsulfonium / p-toluenesulfonate, diphenyl-p-tert-butoxyphenylsulfonium / trifluoromethanesulfonate, diphenyl-p-tert-butoxyphenyl Sulfonium perfluorobutanesulfonate, diphenyl-p-tert-butoxyphenylsulfonium perfluorooctanesulfonate, diphenyl-p-tert-butoxyphenylsulfonium p-toluenesulfonate, diphenyl-p-tert-butoxycarbonyloxyphenylsulfonium Fluorooctane sulfonate, diphenyl-p-tert-butoxycar Examples thereof include bonyloxyphenylsulfonium · 10-camphorsulfonate, diphenyl-p-tert-butoxycarbonyloxyphenylsulfonium · p-toluenesulfonate, 4,4′-di-tert-butyldiphenyliodonium · 10-camphorsulfonate, and the like. it can.

  Specific examples of the acid generator represented by the formula (XVI) include 1,2,3-tris-methanesulfonyloxybenzene, 1,2,3-tris-trifluoromethanesulfonyloxybenzene, 1,2,3-tris. -Perfluorooctanesulfonyloxybenzene, 1,2,3-tris-perfluorobutanesulfonyloxybenzene, 1,2,3-tris-p-toluenesulfonyloxybenzene, 1,2,3-tris-10-camphorsulfonyl Oxybenzene, 1,2,3-tris-trifluoroacetyloxybenzene, 1,2,4-tris-methanesulfonyloxybenzene, 1,2,4-tris-trifluoromethanesulfonyloxybenzene, 1,2,4- Tris-3-tris-perfluorooctanesulfonyloxybenzene, 1 2,4-tris - p-toluenesulfonyloxy benzene, 1,2,4-tris - it can be exemplified perfluorobutane sulfonyloxy benzene.

  Examples of the acid generator represented by the formula (XVII) include succinimide / trifluoromethanesulfonate, succinimide / perfluorobutanesulfonate, succinimide / perfluorooctanesulfonate, succinimide / p-toluenesulfonate, succinate. Acid imide 10-camphor sulfonate, succinimide methane sulfonate, succinimide 1-methylethane sulfonate, succinimide benzene sulfonate, dimethyl succinimide trifluoromethane sulfonate, dimethyl succinimide perfluorooctane sulfonate , Dimethyl succinimide / p-toluene sulfonate, phthalic imide / trifluoromethane sulfonate, phthalic imide / perfluorobutane sulfonate, phthalate Acid imide / perfluorooctane sulfonate, phthalic imide / p-toluene sulfonate, phthalic imide / 10-camphor sulfonate, phthalic imide / methane sulfonate, phthalic imide / benzene sulfonate, 5-norbornene-2,3-dicarboxyl Imido trifluoromethanesulfonate, 5-norbornene-2,3-dicarboximide perfluorobutanesulfonate, 5-norbornene-2,3-dicarboximide perfluorooctanesulfonate, 5-norbornene-2,3-dicarboxyl Examples include imido, p-toluenesulfonate, 5-norbornene-2,3-dicarboximide, 10-camphorsulfonate, 5-norbornene-2,3-dicarboximide, methanesulfonate, etc. It is possible.

  When used as a resist composition, at least one polymer having a repeating unit represented by the formula (I) and, if necessary, a polymer used in an existing chemically amplified positive resist are mixed, XIII) to (XVII) are preferably used alone or in combination of two or more selected from acid generators represented by (XVII). As a preferable example in the case of using two or more kinds of acid generators in combination, the light transmittance is good, the high transparency of the resist composition can be maintained, the heat treatment (PEB) temperature dependency after exposure is small, and An acid generator represented by the formula (XIII) that generates a weak acid by exposure, and a formula (XIV), a formula (XV), or a formula (XVI) that has a high acid generation efficiency or generates a strong acid for a certain exposure amount. Alternatively, it is preferable to use in combination with an acid generator represented by the formula (XVII) from the viewpoint of improving the shape of the bottom of the pattern and removing scum, and among these, the acid generator represented by the formula (XIII) and the formula It is particularly preferable to use (XIV) or / and an acid generator represented by the formula (XV) in combination.

  In addition, as a constituent ratio of the acid generator when two or more acid generators are used in combination, the formula (XIV), the formula (XV), or the formula is used with respect to 100 parts by weight of the acid generator represented by the formula (XIII). The acid generator represented by (XVI) is 1 to 70 parts by weight, preferably 10 to 50 parts by weight.

In addition, various triphenylsulfonium salts and diphenyliodonium salts conventionally used (anions of these onium salts include PF ₆ ⁻ , AsF ₆ ⁻ , BF ₄ ^{− and the} like) and tris (trichloro). Methyl) -s-triazine / triethanolamine, tris (trichloromethyl) -s-triazine / acetamide, or the like, or a compound represented by the above formulas (XIII) to (XVII) It can be used by mixing.

  The basic compound used in the resist composition of the present invention may be any basic compound as long as the sensitivity can be adjusted by adding, but usually a basic compound used in this field, such as polyvinyl chloride. Pyridine, poly (vinyl pyridine / methyl methacrylate), pyridine, piperidine, tribenzylamine, N-methyl-2-pyrrolidone, monoalkylamines [the alkyl group is a straight chain having 1 to 12 carbon atoms, Examples thereof include a branched or cyclic alkyl group, and specifically, 2-methylcyclohexylamine, 4-tert-cyclohexylamine and the like are preferable. ], Dialkylamines [As the alkyl group, a linear, branched or cyclic alkyl group having 1 to 12 carbon atoms can be mentioned, and specifically, dicyclohexylamine, di-n-octylamine and the like are preferable. . ], Trialkylamines [Examples of the alkyl group include linear, branched or cyclic alkyl groups having 1 to 12 carbon atoms, such as tri-n-propylamine, tri-n- Butylamine, tri-n-octylamine, tri-n-hexylamine, triethylamine, dicyclohexylmethylamine, dicyclohexylethylamine, N-methyl-di-n-octylamine, dimethyl-n-dodecylamine, tris (2-ethylhexyl) amine Etc. are preferred. ], Mono, di, trialkanolamines [specifically, triisopropalamine, triethanolamine and the like are preferable. ], Tris [2- (2-methoxyethoxy) ethyl] amine, tetraalkylammonium hydroxide [the alkyl group includes a linear, branched or cyclic alkyl group having 1 to 12 carbon atoms. Specifically, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetra-n-propylammonium hydroxide, tetra-n-butylammonium hydroxide and the like are preferable. However, the present invention is not limited to these. The basic compounds are usually used alone or in combination of two or more.

  As the solvent used in the resist composition of the present invention, a polymer having a repeating unit represented by the formula (I), or the polymer, an acid generator, a basic compound, and a polymer used as necessary. Although it will not be restrict | limited especially if it can melt | dissolve additives, such as a ultraviolet absorber, an acidic compound, and surfactant, Usually, film-formability is favorable and what does not have absorption in 220-300 nm vicinity. More preferred. Specifically, methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, methyl lactate, ethyl lactate, 2-ethoxyethyl acetate, methyl pyruvate, ethyl pyruvate, 3-methoxypropionic acid Methyl, ethyl 3-methoxypropionate, ethyl 2-hydroxybutanoate, ethyl 3-hydroxybutanoate, N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, γ-butyrolactone, γ -Propiolactone, cyclohexanone, methyl ethyl ketone, 2-heptanone, 1,4-dioxane, diethylene glycol monomethyl ether, diethylene glycol dimethyl ether, ethylene group It can be exemplified call monoisopropyl ether, the solvent is used in combination usually alone, or two or more kinds.

  In the resist composition of the present invention, the mixing ratio of the polymer having the repeating unit represented by formula (I) and the acid generator is 1 to 30 acid generators per 100 parts by weight of the polymer. Part by weight, preferably 1 to 20 parts by weight. The amount of the basic compound in the resist composition according to the present invention is 0.5 to 20 parts by weight, preferably 1 to 10 parts by weight with respect to 1000 parts by weight of the polymer. Further, the amount of the solvent in the resist composition according to the present invention is such that the polymer, the acid generator and other additives are dissolved, and the resulting positive resist composition is applied onto the substrate. Although it will not specifically limit if it is the quantity which does not cause trouble on the occasion, Usually, 1-20 weight part with respect to 1 weight part of this polymer, Preferably it is 1.5-10 weight part.

  The resist composition of the present invention comprises the above four components, that is, a polymer having a repeating unit represented by the formula (I), an acid generator, a basic compound, and a solvent as main components. If necessary, an ultraviolet absorber or an acidic compound is used for the purpose of making the shape rectangular or improving the scum and skirting at the interface with the substrate. In addition, a surfactant may be used for the purpose of improving film formability, striation and wettability.

  Examples of the ultraviolet absorber used as necessary in the resist composition of the present invention include 9-diazofluorenone and derivatives thereof, 1-diazo-2-tetralone, 2-diazo-1-tetralone, and 9-diazo. -10-phenantrone, 2,2 ', 4,4'-tetrakis (o-naphthoquinonediazide-4-sulfonyloxy) benzophenone, 2,2', 4,4'-tetrahydroxybenzophenone, 1,2,3-tris (O-naphthoquinonediazide-4-sulfonyloxy) propane, 9- (2-methoxyethoxy) methylanthracene, 9- (2-ethoxyethoxy) methylanthracene, 9- (4-methoxybutoxy) methylanthracene, acetic acid 9-anthracene Methyl, dihydroxyflavanone, quercetin, trihydroxyflavano , Tetrahydroxy flavanones, 4 ', 6-dihydroxy-2-naphthaldehyde, 4,4'-dihydroxybenzophenone, 2,2', 4,4'-tetrahydroxy benzophenone.

  Examples of the acidic compound used as necessary in the resist composition of the present invention include phthalic acid, succinic acid, malonic acid, benzoic acid, salicylic acid, m-hydroxybenzoic acid, p-hydroxybenzoic acid, o- Organic acids such as acetylbenzoic acid, o-acetyloxybenzoic acid, o-nitrobenzoic acid, thiosalicylic acid, thionicotinic acid, salicylaldehyde, salicylhydroxamic acid, succinimide, phthalimide, saccharin, ascorbic acid, etc. .

  Examples of the surfactant include polyethylene glycol stearate, polyethylene glycol dilaurate, polyethylene glycol, polypropylene glycol, polyoxyethylene stearyl ether, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene nonyl ether, polyoxy In addition to nonionic surfactants such as ethylene octyl phenyl ether, various commercially available nonionic surfactants, fluorine-containing nonionic surfactants, fluorine-containing cationic surfactants, fluorine-containing anionic surfactants, cationic interfaces An activator and an anionic surfactant are mentioned. Among the above surfactants, resist film has good film formability, such as Fluorard (trade name of Sumitomo 3M Co., Ltd.), Surflon (trade name of Asahi Glass Co., Ltd.), Unidyne (trade name of Daikin Industries, Ltd.) Fluorine-containing nonionic surfactants such as (trade name of Dainippon Ink Co., Ltd.) and Ftop (trade name of Tochem Products Co., Ltd.) are particularly preferred.

Furthermore, as a plasticizer, for example, diethyl phthalate, dibutyl phthalate, dipropyl phthalate and the like may be appropriately used as necessary.
These UV absorbers, acidic compounds, surfactants, or plasticizers used as necessary in the resist composition according to the present invention may be used in an amount of 0.1 for each 100 parts by weight of the polymer. -10 parts by weight, preferably 0.1-5 parts by weight.

Pattern formation using the resist composition of the present invention is performed, for example, as follows. The resist composition of the present invention is applied to a semiconductor substrate such as a silicon wafer or a radiation-sensitive absorbing film (rotary application of an organic antireflection agent, film formation by baking, or film formation by CVD or sputtering of an inorganic antireflection material). (Any method is possible) Spin coating (about 0.1 to 0.3 μm when used as an upper layer of three layers) so that the thickness is about 0.3 to 2 μm on the semiconductor substrate on which it is formed, For example, prebaking is performed in an oven at 70 to 150 ° C. for 10 to 30 minutes or on a hot plate at 70 to 150 ° C. for 1 to 2 minutes. Next, a mask for forming a target pattern is placed over the resist film, and after irradiation with, for example, far ultraviolet light of 300 nm or less to an exposure amount of about 1 to 100 mJ / cm ² , 70 to 70 on a hot plate. Bake (PEB) at 150 ° C. for 1-2 minutes. Furthermore, using a developer such as 0.1 to 5% tetramethylammonium hydroxide (TMAH) aqueous solution, about 0.5 to 3 minutes, a dip method, a paddle method, a spray method, etc. If development is performed by the conventional method, a target pattern is formed on the substrate.

  As the developer used in the pattern forming method as described above, an aqueous alkali solution having an appropriate concentration that can increase the difference in solubility between the exposed and unexposed areas is selected according to the solubility of the resist composition. Usually, it is selected from the range of 0.01 to 20%. Examples of the alkaline aqueous solution used include aqueous solutions containing organic amines such as TMAH, choline, and triethanolamine, and inorganic alkalis such as NaOH and KOH.

In the resist composition of the present invention, acid is generated and chemically amplified by i-line exposure, electron beam irradiation and soft X-ray irradiation as well as deep ultraviolet light and KrF excimer laser light. Therefore, the resist composition of the present invention is a resist composition that can form a pattern by a low exposure amount of far ultraviolet light, KrF excimer laser light, i-line exposure, electron beam irradiation, or soft X-ray irradiation method using a chemical amplification action. It is.
The action when the polymer of the present invention is used as a resist composition will be described with reference to specific examples. First, an acid is generated at a site exposed by far ultraviolet light, KrF excimer laser light or the like according to a photoreaction.

  When the heat treatment is carried out following the exposure process, the exposed part of the exposed part is cleaved by the generated acid, the ester group part in the main chain becomes a low-molecular oligomer or monomer, becomes alkali-soluble, and is eluted in the developer during development. To do.

  On the other hand, since no acid is generated in the unexposed area, the functional group does not undergo chemical change due to the acid and is difficult to dissolve in the alkaline developer. Thus, when pattern formation is performed using the resist composition of the present invention, the difference in dissolution rate with respect to the alkaline developer between the exposed area and the unexposed area becomes extremely large, resolution performance is improved, and DOF is improved. Expands.

  Since this effect is exhibited as the resist film becomes thinner, this characteristic is extremely advantageous for the thinning of the resist film, which will be advanced with future miniaturization of design rules.

EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example, the scope of the present invention is not limited to an Example.
The methods for purifying the reagents and solvents used in the examples of the present invention are described below.
The solvents and raw materials used were purified according to the usual procedure. Tetrahydrofuran (THF) was distilled from sodium benzophenone ketyl. Ketenes were distilled under reduced pressure after reacting acid chloride with triethylamine in THF at room temperature. Lithium chloride was heated and dried under vacuum in a polymerization vessel. Aldehydes were distilled under reduced pressure after adding CaH ₂ .
As n-butyllithium (n-BuLi), a commercially available n-BuLi hexane solution (1.6 mol / l) was used as it was.

Reference Example 1 (Synthesis of ethylphenylketene (EPK))
Under a nitrogen atmosphere, a THF solution of 55 g (0.3 mol) of 2-phenylbutyryl chloride was added dropwise to a mixed solution of 91 g (0.9 mol) of triethylamine in tetrahydrofuran (THF). One hour later, the precipitated triethylamine hydrochloride was filtered, and the filtrate was distilled under reduced pressure to obtain EPK (60 to 70 ° C./4 mmHg). Yield 30 g (70% yield).

Reference Example 2 (Synthesis of 3- (2-ethoxyethoxy) benzaldehyde (mEEBA))
In a nitrogen atmosphere, 50.0 g (0.4 mol) of 3-hydroxybenzaldehyde was dissolved in 75 g of THF, and then 59.0 g (0.8 mol) of vinyl ethyl ether and 2.0 ml (8 mmol) of hydrochloric acid were added at room temperature. Stir at night. After adding a Na ₂ CO ₃ aqueous solution and neutralizing, liquid separation was performed, and the upper layer was washed with water until pH = 7. Anhydrous Na ₂ SO ₄ was added, dehydrated and filtered, concentrated to dryness, and mEEBA was obtained by distillation under reduced pressure (70 to 77 ° C./0.5 mmHg). Yield 69 g (87% yield).

Reference Example 3 (Synthesis of 4- (2-ethoxyethoxy) benzaldehyde (pEEBA))
In a nitrogen atmosphere, 24.4 g (0.2 mol) of 4-hydroxybenzaldehyde was dissolved in 200 ml of ethyl acetate, and then 21.6 g (0.3 mol) of vinyl ethyl ether and 0.2 ml (2 mmol) of hydrochloric acid were added at room temperature. And stirred overnight. A Na ₂ CO ₃ aqueous solution was added and the mixture was neutralized and separated, and the upper layer was washed with water until pH = 7. MgSO ₄ was added, dehydrated and filtered, concentrated to dryness, and pEEBA was obtained by distillation under reduced pressure (100 to 105 ° C./0.4 mmHg). Yield 20 g (yield 50%).

Example 1 (Copolymerization of EPK and mEEBA)
After heating and vacuum drying 1.9 g (45 mmol) of lithium chloride, 100 ml of THF was added under a nitrogen atmosphere, and the mixture was cooled to −40 ° C. Further, 6.2 g (32 mmol) of mEEBA and 4.4 g (30 mmol) of EPK were added, and then 0.93 ml (1.5 mmol) of a hexane solution of n-BuLi was added, and the reaction was continued at −40 ° C. for 30 minutes. After stopping the reaction by adding methanol, the mixture was added to a large amount of methanol for reprecipitation, and the resulting precipitate was filtered and dried under reduced pressure to obtain 9.3 g of a white powdery polymer (a1). When the polymer (a1) was analyzed by gel permeation chromatography (hereinafter abbreviated as “GPC”), it was a monodisperse polymer with Mn = 4900 and Mw / Mn = 1.20.

Comparative Example 1 (copolymerization of EPK and pEEBA)
After heating and vacuum drying 1.9 g (45 mmol) of lithium chloride, 100 ml of THF was added under a nitrogen atmosphere, and the mixture was cooled to −40 ° C. Further, 6.2 g (32 mmol) of pEEBA and 4.4 g (30 mmol) of EPK were added, 0.93 ml (1.5 mmol) of a hexane solution of n-BuLi was added, and the reaction was continued at −40 ° C. for 30 minutes. After stopping the reaction by adding methanol, the mixture was added to a large amount of methanol for reprecipitation, and the resulting precipitate was filtered and dried under reduced pressure to obtain 9.5 g of white powdery polymer (a). When the polymer (a) was analyzed by GPC, it was a monodisperse polymer with Mn = 4800 and Mw / Mn = 1.25.

Example 2 [Copolymerization of EPK with mEEBA and pEEBA (mEEBA / pEEBA molar ratio = 1/1)]
After heating and vacuum drying 3.0 g (71 mmol) of lithium chloride, 109 g of THF was added under a nitrogen atmosphere, and the mixture was cooled to −40 ° C. Further, 5.6 g (29 mmol) of pEEBA, 5.6 g (29 mmol) of mEEBA and 8.0 g (55 mmol) of EPK were added, and then 1.18 g (3.0 mmol) of hexane solution of n-BuLi was added. The reaction was continued at 40 ° C. for 30 minutes. After stopping the reaction by adding methanol, the reaction solution was washed with water until the pH became 7. The organic layer was concentrated to dryness, redissolved in 45 g of THF, re-precipitated by adding it to a large amount of 33% aqueous methanol solution, and the resulting precipitate was filtered and dried under reduced pressure, whereby a white powdery polymer (b) was treated with 19. 4 g was obtained. When the polymer (b) was analyzed by GPC, it was a monodisperse polymer with Mn = 4700 and Mw / Mn = 1.16. ^{By 13} C-NMR, a signal of methine carbon sandwiched between oxygen in the acetal was observed in the vicinity of 76-82 ppm, and a signal indicating the carbonyl carbon of the ester was observed in the vicinity of 171 ppm. Further, an aromatic ring carbon signal of mEEBA unit was observed in the vicinity of 123 ppm. From this integrated value, it was confirmed that the composition ratio of the polymer was mEEBA / pEEBA = 1/1.

Example 3 [Copolymerization of EPK with mEEBA and pEEBA (mEEBA / pEEBA molar ratio m / p = 1/3)]
A white powdery polymer (c) was obtained in the same manner as in Example 2 except that the amounts of mEEBA and pEEBA were changed. When the polymer (c) was analyzed by GPC, it was a monodisperse polymer with Mn = 6400 and Mw / Mn = 1.22. ^{By 13} C-NMR, a signal of methine carbon sandwiched between oxygen in the acetal was observed in the vicinity of 76-82 ppm, and a signal indicating the carbonyl carbon of the ester was observed in the vicinity of 171 ppm. Further, an aromatic ring carbon signal of mEEBA unit was observed in the vicinity of 123 ppm, and from this integrated value, it was confirmed that the composition ratio of the polymer was mEEBA / pEEBA = 1/3.

Example 4 [Copolymerization of EPK with mEEBA and pEEBA (mEEBA / pEEBA molar ratio m / p = 3/1)]
A white powdery polymer (d) was obtained in the same manner as in Example 2 except that the amounts of mEEBA and pEEBA were changed. When the polymer (d) was analyzed by GPC, it was a monodisperse polymer with Mn = 7205 and Mw / Mn = 1.22. ^{By 13} C-NMR, a signal of methine carbon sandwiched between oxygen in the acetal was observed in the vicinity of 76-82 ppm, and a signal indicating the carbonyl carbon of the ester was observed in the vicinity of 171 ppm. Further, an aromatic ring carbon signal of mEEBA unit was observed in the vicinity of 123 ppm, and from this integrated value, it was confirmed that the composition ratio of the polymer was mEEBA / pEEBA = 3/1.

Example 5
The polymer (a1) is dissolved in propylene glycol monomethyl ether acetate (PGMEA) so as to have a resin solid content concentration of 10%, and triphenylsulfonium trifluoromethanesulfonate is further added to 1.0% by weight based on the resin solid content. To prepare a resist solution. A film was formed on a silicon wafer using the resist solution by a spin coater and heated on a hot plate at 90 ° C. for 60 seconds to obtain a thin film having a thickness of 400 nm. After exposure with light having a wavelength of 248 nm, the plate was heated at 110 ° C. for 90 seconds to measure the film thickness. As a result, when the exposure amount was ² mJ / cm ² or more, almost no change in film thickness was observed, and it was almost 300 nm. From this result, it was found that deprotection efficiently progressed by exposure, and that the film thickness was not reduced by post-curing. Further, when GPC was measured, it was confirmed that no main chain was cleaved since no low molecular weight peak was observed.

Furthermore, the film thickness was measured after developing for 180 seconds at 23 ° C. using an aqueous 2.38% tetramethylammonium hydroxide solution. As a result, it was found that the film was dissolved when the exposure amount was about 7 mJ / cm ² or more. From the above, it was found that the meta-substituted product has a property of being deprotected and dissolved in an alkaline aqueous solution under normal conditions, but is less susceptible to main chain cleavage.

Example 6
Polymers (b), (c) and (d) were each dissolved in propylene glycol monomethyl ether acetate (PGMEA) so as to have a resin solid content concentration of 10%, and triphenylsulfonium trifluoromethanesulfonate was added to the resin solid content. The resist solution was prepared by adding 1.0% by weight. A film was formed on a silicon wafer using the resist solution by a spin coater and heated on a hot plate at 90 ° C. for 60 seconds to obtain a thin film having a thickness of 400 nm. After exposure with light having a wavelength of 248 nm, the plate was heated at 130 ° C. for 90 seconds to measure the film thickness. The relationship between the exposure amount and the film thickness is shown in FIG.

Furthermore, the film thickness was measured after developing for 180 seconds at 23 ° C. using an aqueous 2.38% tetramethylammonium hydroxide solution. FIG. 2 shows the relationship between the exposure amount and the film thickness. At the same time, the dissolution rate during development was measured, and the relationship between the exposure dose and the dissolution rate is shown in FIG.
Comparative Example 2
A resist solution was prepared in the same manner as in Example 3 except that the polymer (a) was used. The film was processed in the same manner as in Example 3 except that the pot plate temperature after exposure was changed to 110 ° C., and the relationship between the exposure amount and the film thickness is shown together in FIG. Furthermore, the film thickness was measured after developing for 180 seconds at 23 ° C. using an aqueous 2.38% tetramethylammonium hydroxide solution. The relationship between the exposure amount and the film thickness is shown together in FIG. At the same time, the dissolution rate during development was measured, and the relationship between the exposure amount and the dissolution rate is summarized in FIG.

From the results of FIG. 1, it was found that the polymers (b), (c) and (d) showed little film loss even at a high exposure amount of 50 mJ / cm ² . At that time, GPC analysis of the membrane revealed that the main chain was effectively cleaved.
From the results of FIGS. 2 and 3, the polymers (b), (c), and (d) show high contrast characteristics, and the composition using the polymer of the present invention is suitable for alkali development and has a pattern with excellent contrast. It was found that it can be formed.

It is a figure which shows the relationship between the exposure time after PEB in Example 6, and the comparative example 2, and a film thickness. It is a figure which shows the relationship between the exposure time after the alkali image development in Example 6, and the comparative example 2, and a film thickness. It is a figure which shows the relationship between the exposure time after the alkali image development in Example 6, and the comparative example 2, and a dissolution rate.

Claims (11)

Formula (I)

(Wherein R ₁ and R ₂ are each independently a hydrogen atom, a halogen atom, a C1-C20 hydrocarbon group, a heterocyclic group, a cyano group, a nitro group, a C (═O) R ₄ group, S (O ) _N R ₄ group, P (═O) (R ₄ ) ₂ group or M (R ₄ ) ₃ group, wherein R ₄ is a C1-C20 hydrocarbon oxy group, C1-C20 hydrocarbon group, C1- Represents a hydrocarbon thio group of C20 or a mono- or di-C1-C20 hydrocarbon amino group, M represents a silicon atom, a germanium atom, a tin atom or a lead atom, and n represents any of 0, 1, or 2 R ₃ represents the formula (IIA)

(In the formula, R ₅ represents a hydrogen atom or a group capable of decomposing / eliminating with an acid, R ₆ represents a halogen atom or a C1-C20 hydrocarbon group, and m represents an integer of 1 to 3. P represents an integer of 0 or 1 to 3 and represents m + p ≦ 5. When m is 2 or more, R ₅ may be the same or different, and when p is 2 or more, R 5 ₆ may be the same or different, and the OR ₅ substitution position is at least one or more positions selected from the para position and the ortho position of the main chain bonding position. IIB)

(In the formula, R ₁₅₁ represents a hydrogen atom or a group capable of decomposing / eliminating with an acid, R ₁₆₁ represents a halogen atom or a C1-C20 hydrocarbon group, m1 represents 1 or 2, and p1 represents 0. Or any one of 1 to 3, m1 + p1 ≦ 5, and when m1 is 2, R ₁₅₁ may be the same or different, and when p1 is 2 or more, R ₁₆₁ is the same or different. And the OR ₁₅₁ substitution position is any of the substituents represented by the meta position of the main chain binding position. Have a repeating unit represented by), the molar ratio of the repeating unit having a repeating unit with the substituents represented by formula (IIB) having a substituent represented by formula (IIA) is 99 / 1-1 / 99. A copolymer having a number average molecular weight of 2,000 to 50,000 . _{2. The} copolymer according to claim 1, wherein in the repeating unit represented by the formula (I), R ₁ and R ₂ each independently represent a C1 to C20 hydrocarbon group. The ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the polymer having a repeating unit represented by the formula (I) is in the range of 1.01 to 3.00. The copolymer according to claim 1 or 2 , characterized in that An acid-decomposable composition comprising the copolymer according to any one of claims 1 to 3 and a compound that generates an acid by an acid or external stimulus. The acid-decomposable composition according to claim 4 , wherein the external stimulus is at least one selected from the group consisting of heat, pressure, and radiation sensitivity. The acid-decomposable composition according to claim 4 , wherein the compound that generates an acid by an external stimulus is a photosensitive compound that generates an acid by radiation-sensitive irradiation. A photoresist composition comprising the acid-decomposable composition according to claim 4 . The photoresist composition according to claim 7 , further comprising a solvent. The photoresist composition according to claim 7 , further comprising a basic compound. 10. The photoresist composition according to claim 7 , wherein in the repeating unit represented by the formula (I), R ₁ and R ₂ each independently represent a C1 to C20 hydrocarbon group. object. The ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the polymer having a repeating unit represented by the formula (I) is in the range of 1.01 to 3.00. The photoresist composition according to any one of claims 7 to 10 , characterized in that