JP3072316B2 - Resist composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation-sensitive composition, and more particularly, to ultrafine processing of a semiconductor device using radiation such as far ultraviolet rays such as an excimer laser and charged particle beams such as an X-ray and an electron beam. The present invention relates to a radiation-sensitive composition suitable as a novel resist.

[0002]

2. Description of the Related Art When manufacturing semiconductor devices, a resist is applied to the surface of a silicon wafer to form a photosensitive film, a latent image is formed by irradiating light, and then developed to form a negative or positive image. The image is obtained by the lithography technology. By the way, IC, LSI, and VLSI
With the high integration, high density and miniaturization of semiconductors,
A technique for forming a fine pattern of 5 μm or less is required. However, it is extremely difficult to accurately form a fine pattern of 0.5 μm or less by conventional lithography using near-ultraviolet light and visible light, and the yield is remarkably reduced. For this reason, in place of conventional photolithography using near-ultraviolet light having a wavelength of 350 to 450 nm, in order to enhance exposure resolution, far-ultraviolet light (short-wavelength ultraviolet light) having a short wavelength, krypton fluoride laser (KrF excimer laser light) is used. Lithography technology using an electron beam or the like has been studied.
In conventional lithography utilizing near-ultraviolet light, a novolak resin is used as a base polymer. The resin has a good transmittance for ultraviolet light having a wavelength of 350 to 450 nm, but has a long wavelength shorter than that. Since the transmittance for ultraviolet rays and KrF excimer laser light is extremely deteriorated, when the resin is used as a base polymer, there are known problems that sufficient sensitivity cannot be obtained and the pattern shape is poor. Have been. For the purpose of improving poor transmittance, a chemically amplified resist using a polyvinylphenol derivative as a base polymer has been studied (Japanese Patent Publication No. 2-276).
No. 60), however, the pattern shape has not yet satisfied the requirements. Further, as a recent example, a method of using a hydrogenated polyvinyl phenol derivative as a base polymer for the purpose of further improving the transmittance (Japanese Patent Application Laid-Open No. 5-249673) is known. Although the pattern shape has been considerably improved by this improvement, further improvement is required for the required characteristics of a more advanced resist, particularly for the resolution.

[0003]

Under these prior arts, the inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that in addition to the (substituted) acrylic acid 1-alkylcycloalkylester unit, It has been found that a resist composition having excellent resist properties can be obtained by using a resin having another (substitutable) acrylate unit or a substitutable styrene unit, and the present invention has been completed based on this finding. Was.

[0004]

Thus, according to the present invention, the general formulas (1), (2) and (3)

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Embedded image (In the formulas (1) to (3), R ^{1 to} R ³ are each independently a hydrogen atom, a substitutable alkyl group having 1 to 4 carbon atoms, a halogen atom, a cyano group, or a nitro group, and R ⁴ is a straight-chain. R ⁵ and R ⁶ are each independently a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxyl group, a carboxyl group, Straight-chain, branched or cyclic C1-C8 substitutable alkyl group, straight-chain, branched or cyclic C1-C8
A substituted aryl group having 6 to 12 carbon atoms, a substituted aralkyl group having 7 to 14 carbon atoms,
⁷ is a linear, branched or cyclic C1-C8 substitutable alkyl group, or a linear, branched or cyclic C1-C8 substitutable alkenyl group. R ^{8 to} R ¹¹ are a hydrogen atom, a halogen atom, or a substitutable alkyl group having 1 to 4 carbon atoms, at least one of which is a hydrogen atom. A is a single bond or a divalent substitutable organic group. Equations (1), (2) and (3)
Are represented by k, m, and n, respectively.
k + m + n = 1, 0 <k ≦ 1, 0 ≦ m <1, 0 ≦
n <1. After exposing a resist film containing a polymer having the structural unit represented by the formula (1) and a radiation-sensitive component that generates an acid upon irradiation with activating radiation, followed by a heat treatment after a lapse of 15 to 120 minutes. And a method for forming a pattern, wherein the above formulas (1), (2) and (3)

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Embedded image (In the formulas (1) to (3), R ^{1 to} R ³ are each independently a hydrogen atom, a substitutable alkyl group having 1 to 4 carbon atoms, a halogen atom, a cyano group, or a nitro group, and R ⁴ is a straight-chain. R ⁵ and R ⁶ are each independently a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxyl group, a carboxyl group, Straight-chain, branched or cyclic C1-C8 substitutable alkyl group, straight-chain, branched or cyclic C1-C8
A substituted aryl group having 6 to 12 carbon atoms, a substituted aralkyl group having 7 to 14 carbon atoms,
⁷ is a linear, branched or cyclic C1-C8 substitutable alkyl group, or a linear, branched or cyclic C1-C8 substitutable alkenyl group. R ^{8 to} R ¹¹ are a hydrogen atom, a halogen atom, or a substitutable alkyl group having 1 to 4 carbon atoms, at least one of which is a hydrogen atom. A is a single bond or a divalent substitutable organic group. Equations (1), (2) and (3)
Are represented by k, m, and n, respectively.
k + m + n = 1, 0 <k ≦ 1, 0 ≦ m <1, 0 ≦
n <1. A resist composition comprising a polymer having a polymerization average molecular weight of 4,960 to 8,860 having a structural unit represented by formula (1) and a radiation-sensitive component that generates an acid upon irradiation with activating radiation. You.

Hereinafter, the present invention will be described in detail. The resin used in the present invention is a polymer having the structural units represented by the formulas (1) to (3). When this polymer is a copolymer, it may be a block copolymer or a random copolymer. The lower limit of the polymerization average molecular weight of this polymer is usually 1,000, preferably 2,000, and the upper limit is usually 100,000, preferably 20,000. If the molecular weight is low, the mechanical strength of the resist film becomes weak, while if the molecular weight is high, the viscosity tends to be high, and it tends to be difficult to obtain a uniform resist film. In the formulas (1) to (3), specific examples of R ^{1 to} R ³ include a hydrogen atom; a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an s-butyl group, and a t-butyl. An alkyl group having 1 to 4 carbon atoms such as a group or a substituent in which one or more hydrogen atoms of these alkyl groups are substituted with a halogen atom, an alkoxy group or the like; a halogen atom such as fluorine, chlorine, bromine or iodine;
A cyano group; a nitro group. R ^{4 in the} formula (1) is
Methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, s-butyl group, t-butyl group, pentyl group, isopentyl group, hexyl group, 1-ethylbutyl group, 4-methylpentyl group, heptyl Group, 1-methylpentyl group, 4-methylhexyl group, 3,3-dimethylpentyl group, octyl group, 1-ethylhexyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group,
Cyclooctyl group, 2-methoxyethyl group, 2-ethoxyethyl group, chloromethyl group, 2-chloroethyl group, 2
-Methylcyclopentyl group, 5-methoxypentyl group,
A straight-chain, branched or cyclic alkyl group having 1 to 8 carbon atoms such as a 3,3-dichlorocyclooctyl group or a substituent in which one or more hydrogen atoms of these alkyl groups are substituted with a halogen atom, an alkoxy group or the like; Vinyl group, 1-propenyl group, 1-buten-1-yl group, 1-buten-2-yl group, 2-buten-2-yl group, 1-penten-2-yl group, 2-hexen-2-yl Linear, branched or cyclic C1-C8 substitutable alkenyl groups such as a group, 3-hepten-3-yl group and 1-octen-6-yl group.

In the formula (2), R ⁵ and R ⁶ are each independently a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxyl group,
A carboxyl group, a linear, branched or cyclic C1-C8 substitutable alkyl group as described above; a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, an s-butoxy group, t-butoxy group, pentoxy group, isopentoxy group, hexyloxy group, 1-ethoxybutoxy group, 4-methylpentoxy group, heptoxy group, 1-methylpentoxy group, 4-methylhexyl group,
3,3-dimethylpentoxy group, octoxy group, 1-ethylhexyl group, cyclopentoxy group, cyclohexyloxy group, cycloheptoxy group, cyclooctoxy group,
2-methoxyethoxy group, 2-ethoxyethoxy group, chloromethoxy group, 2-chloroethoxy group, 2-methylcyclopentoxy group, 5-methoxypentoxy group, 3,3
A straight-chain, branched or cyclic alkoxy group having 1 to 8 carbon atoms such as a dichlorocyclooctoxy group, or a carbon atom having 1 to 8 carbon atoms in which at least one hydrogen atom of these alkoxy groups is substituted with a halogen atom, an alkoxy group or the like; Phenyl group, 4-methylphenyl group, 2,4
-Dimethylphenyl group, 3,5-dichlorophenyl group,
6 to 6 carbon atoms such as a 4-methoxyphenyl group and a naphthyl group
12 substitutable aryl groups; benzyl group, phenethyl group,
4-methylbenzyl group, 3-chlorophenethyl group, 2-
Examples thereof include a substituted aralkyl group having 7 to 14 carbon atoms such as a methylnaphthyl group. Among them, a hydroxyl group is a preferable example because adhesion to a substrate is improved. Equation (3)
R ⁷ is a linear, branched or cyclic C 1 group as described above.
A substituted or unsubstituted alkenyl group having 1 to 8 carbon atoms; In formula (1), R ^{8 to} R ¹¹ are a hydrogen atom, a halogen atom, or a substitutable alkyl group having 1 to 4 carbon atoms as described above, at least one of which is a hydrogen atom. If there is no more than one hydrogen atom, it will not function as an acid labile group, and the larger the number of hydrogen atoms, the more easily it will be cleaved by an acid. A in the formula (1) is a single bond or a divalent substituted organic group. Specific examples of the divalent substitutable organic group _{herein, -CH 2 -, - C 2} H 4 -, - C 3 H 6 -, - C 4 H
_{8 -, - C 5 H 10} - represented by alkylene or some or all halogen atoms of these hydrogen atom, a cyano group, a hydroxyl group, an alkyl group having 1 to 4 carbon atoms - -C _n H _2n such as ,
Alkoxy group having 1 to 4 carbon atoms, -CHCl substituted alkenyl group having 2 to 5 carbon atoms _{-, - CH 2 C (CN} ) H
_{-, - C (CH 3)} H -, - CH 2 C (CH 3) H -, -
_{CH 2 C (CH 3) HCH} 2 -, - C (OCH 3) H -, -
_{CH (CH = CH 2) CH} 2 - optionally substituted alkylene, such as;
-CH = CH -, - C ( CH 3) = CH-CH 2 -, - C
(CH ₃ ) = a divalent substitutable organic group such as a substitutable alkenylene such as CHCl—. The number of carbon atoms of such an organic group is usually 1 to 5, preferably 3 or 4, in terms of the number of carbon atoms other than those derived from a cyano group, an alkyl group, or an alkenyl group bonded as a substituent.

The proportions of the structural units represented by the formulas (1), (2) and (3) in the resin are represented by k, m and n, and k + m +
n = 1, 0 <k ≦ 1, 0 ≦ m <1, and 0 ≦ n <1.
That is, a polymer having only the structural unit represented by the formula (1) may be used, but a polymer not containing the structural unit represented by the formula (1) does not achieve the object of the present invention. Therefore, the ratio k of the structural unit represented by the formula (1) is usually 0 <k ≦ 1,
Preferably 0.2 ≦ k ≦ 1, more preferably 0.4 ≦ k
≦ 1.

The polymer having the structural units represented by the formulas (1) to (3) used as the resin component in the present invention is:
It is synthesized according to a conventional method. For example, a method of mixing and polymerizing a monomer giving a structural unit represented by each formula at a desired ratio, a method of giving a monomer giving a structural unit of formula (1) or (2) and formula (2) and an acrylate After polymerizing the compounds, the formula (1)
And a method of introducing the R ⁴ and R ⁷ of formula (3). Further, those obtained by partially hydrogenating the obtained polymer can also be used in the present invention. Specific examples of the monomer giving the structural unit of the formula (1) include 1-methylcyclopentyl
Acrylate, 1-methylcyclohexyl acrylate, 1-ethylcyclopentyl acrylate, 1-ethylcyclohexyl acrylate, 1-methylcycloheptyl acrylate, 1-propylcycloheptyl acrylate, 1-methylcyclooctyl acrylate, 1-methylcyclopentyl methacrylate, 1
-Methylcyclohexyl methacrylate, 1-ethylcyclopentyl methacrylate, 1-ethylcyclohexyl methacrylate, 1-methylcycloheptyl
Examples thereof include 1-alkylcycloalkylester compounds of substituted acrylic acid such as methacrylate, 1-propylcycloheptyl methacrylate, and 1-methylcyclooctyl methacrylate. Specific examples of the monomer giving the structural unit of the formula (2) include styrene, 4-methylstyrene, 4-hydroxystyrene, 3-hydroxystyrene, 2-hydroxystyrene, 4-carboxystyrene, and 3-carboxystyrene. , 2-carboxystyrene, 4-nitrostyrene, 3-nitrostyrene, 2-nitrostyrene, 2,4-dimethylstyrene, 2-methyl-4-hydroxystyrene, 3-methyl-4-hydroxystyrene, 4-chlorostyrene , 4- (chloromethyl) styrene, 4-methoxystyrene, 3-methoxystyrene, 2-methoxystyrene, 4-tert-butoxystyrene, 3-tert-butoxystyrene, 2-tert-butoxystyrene, and other substituted styrene compounds And similar α-methylstyrene derivatives.

Specific examples of the monomer component giving the structural unit of the above formula (3) include methyl acrylate, ethyl acrylate, isopropyl acrylate, t-butyl acrylate, t-amyl acrylate, cyclohexyl acrylate, adamantyl acrylate, and methyl methacrylate. And substituted acrylates such as ethyl methacrylate, isopropyl methacrylate, t-butyl methacrylate, t-amyl methacrylate, cyclohexyl methacrylate and adamantyl methacrylate.

Specific examples of the resin used in the present invention include poly (1-methylcyclohexyl (meth) acrylate), poly (1-methylcyclopentyl (meth) acrylate), 1-methylcyclohexyl (meth) acrylate / styrene copolymer, 1-methylcyclopentyl (meth) acrylate / 4-hydroxystyrene copolymer, 1-methylcyclohexyl (meth) acrylate / methyl methacrylate copolymer, 1-methylcyclohexyl methacrylate / adamantyl methacrylate copolymer, 1-methylcyclohexyl methacrylate / 4-hydroxystyrene / adamantyl Methacrylate copolymer, 1-ethylcyclopentyl (meth) acrylate / 4-hydroxystyrene copolymer, 1-propylcyclopen (Meth) acrylate / 4-hydroxystyrene copolymer, 1-methylcyclopentyl (meth) acrylate / 4-hydroxystyrene / ethyl methacrylate copolymer, 1-methylcyclohexyl (meth) acrylate / 4-hydroxystyrene copolymer / vinyl (meth) acrylate Copolymers, such as 1-ethylcycloheptyl (meth) acrylate / 2-methyl-4-hydroxystyrene / t-butyl (meth) acrylate copolymer, are exemplified.

The acid generator (hereinafter referred to as PAG) used in the present invention is not particularly limited as long as it generates a Bronsted acid or Lewis acid when exposed to activating radiation. Organic compounds,
Known compounds such as quinonediazide compounds, α, α-bis (sulfonyl) diazomethane compounds, α-carbonyl-α-sulfonyldiazomethane compounds, sulfone compounds, organic acid ester compounds, organic acid amide compounds, and organic acid imide compounds can be used. it can. As onium salts, diazonium salts, ammonium salts, iodonium salts such as diphenyliodonium triflate, sulfonium salts such as triphenylsulfonium triflate,
Examples thereof include a phosphonium salt, an arsonium salt, and an oxonium salt.

The halogenated organic compounds include halogen-containing oxadiazole compounds, halogen-containing triazine compounds, halogen-containing acetophenone compounds, halogen-containing benzophenone compounds, halogen-containing sulfoxide compounds, halogen-containing sulfone compounds,
Halogen-containing thiazole compounds, halogen-containing oxazole compounds, halogen-containing triazole compounds, halogen-containing 2-pyrone compounds, other halogen-containing heterocyclic compounds, halogen-containing aliphatic hydrocarbon compounds,
Examples thereof include a halogen-containing aromatic hydrocarbon compound and a sulfenyl halide compound, and specifically, tris (2,
3-dibromopropyl) phosphate, tris (2,3
-Dibromo-3-chloropropyl) phosphate, tetrabromochlorobutane, hexachlorobenzene, hexabromobenzene, hexabromocyclododecane, hexabromobiphenyl, allyltribromophenyl ether, tetrachlorobisphenol A, tetrabromobisphenol A, tetrachlorobisphenol A bis (chloroethyl) ether, tetrabromobisphenol A bis (bromoethyl) ether, bisphenol A bis (2,3-dichloropropyl) ether, bisphenol A bis (2,3-dibromopropyl) ether, tetrachlorobisphenol A screw (2,3-
Dichloropropyl) ether, bis (2,3-dibromopropyl) ether of tetrabromobisphenol A,
Tetrachlorobisphenol S, tetrabromobisphenol S, bis (chloroethyl) ether of tetrachlorobisphenol S, bis (bromoethyl) ether of tetrabromobisphenol S, bis (2,3-dichloropropyl) ether of bisphenol S, bis of bisphenol S (2,3-dibromopropyl) ether,
Tris (2,3-dibromopropyl) isocyanurate, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, 2,2-bis (4- (2-hydroxyethoxy) -3,5- Halogen-based flame retardants such as dibromophenyl) propane, dichlorodiphenyltrichloroethane, pentachlorophenol, 2,4,6-trichlorophenyl 4-nitrophenyl ether, 2,4
-Dichlorophenyl 3'-methoxy-4'-nitrophenyl ether, 2,4-dichlorophenoxyacetic acid,
4,5,6,7-tetrachlorophthalide, 1,1-bis (4-chlorophenyl) ethanol, 1,1-bis (4
-Chlorophenyl) -2,2,2-trichloroethanol, 2,4,4 ', 5-tetrachlorodiphenyl sulfide, and organic chloro pesticides such as 2,4,4', 5-tetrachlorodiphenyl sulfone. You.

Specific examples of the quinonediazide compound include:
1,2-benzoquinonediazide-4-sulfonic acid ester, 1,2-naphthoquinonediazide-4-sulfonic acid ester, 1,2-naphthoquinonediazide-5-sulfonic acid ester, 2,1-naphthoquinonediazide-4-sulfonic acid Ester, 2,1-benzoquinonediazide-5
Sulfonic acid esters of quinonediazide derivatives such as sulfonic acid esters, 1,2-benzoquinone-2-diazide-4-sulfonic acid chloride, 1,2-naphthoquinone-2-diazide-4-sulfonic acid chloride, 1,2-
Sulfonic acids of quinonediazide derivatives such as naphthoquinone-2-diazide-5-sulfonic acid chloride, 1,2-naphthoquinone-1-diazide-6-sulfonic acid chloride and 1,2-benzoquinone-1-diazide-5-sulfonic acid chloride Chloride and the like.

As the α, α-bis (sulfonyl) diazomethane-based compound, an α, α-bis (sulfonyl) diazomethane-based compound having an alkyl group, an alkenyl group, an aralkyl group, an aromatic group, or a heterocyclic group, which is unsubstituted or symmetrically or asymmetrically substituted. α-bis (sulfonyl) diazomethane and the like. Specific examples of the α-carbonyl-α-sulfonyldiazomethane-based compound include an unsubstituted, symmetrically or asymmetrically substituted alkyl, alkenyl, aralkyl, aromatic, or heterocyclic group-containing α-carbonyl-α-sulfonyldiazomethane-based compound. Carbonyl-α-sulfonyldiazomethane and the like. Specific examples of the sulfone compound include a sulfone compound having an unsubstituted, symmetrically or asymmetrically substituted alkyl group, alkenyl group, aralkyl group, aromatic group, or heterocyclic group (eg, diphenyl sulfone, dinitrile sulfone) ,
4,4′-dimethylsulfone) and disulfone compounds (diphenylsulfone, di (phenylsulfone) methane, etc.).

Examples of the organic acid esters include carboxylic acid esters, sulfonic acid esters such as hydroquinone monotosylate, and phosphonic acid esters. Examples of the organic acid amides include carboxylic acid amide, sulfonic acid amide, and phosphonic acid amide. Examples of the organic acid imide include carboxylic imide, sulfonic imide, and phosphonic imide.

These PAGs may be used alone or as a mixture of two or more. The lower limit of the amount of these PAGs is usually 0.01 part by weight, preferably 0.2 part by weight, based on 100 parts by weight of the resin used in the present invention.
The upper limit is usually 50 parts by weight, preferably 30 parts by weight.
If the amount is less than 0.01 parts by weight, pattern formation becomes impossible. If the amount is more than 50 parts by weight, problems such as the occurrence of undeveloped residue and the deterioration of the pattern shape occur, and in either case, it is not preferable in terms of resist performance.

In the present invention, the resist composition comprising the resin and PAG is used after being dissolved in a solvent. As the solvent, those generally used as solvents for resist compositions can be used. Specific examples include ketones such as acetone, methyl ethyl ketone, cyclohexanone, cyclopentanone, cyclopentanone and cyclohexanone; n-propanol , I-propanol, n-
Alcohols such as butanol, i-butanol, t-butanol and cyclohexanol; ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether and dioxane; ethylene glycol dimethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol mono Alcohol ethers such as ethyl ether; esters such as propyl formate, butyl formate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, methyl butyrate, and ethyl butyrate;
Oxycarboxylates such as methyl oxypropionate, ethyl 2-oxypropionate, methyl 2-methoxypropionate and ethyl 2-methoxypropionate; cellosolve acetate, methyl cellosolve acetate, ethyl cellosolve acetate, propyl cellosolve acetate, butyl cellosolve acetate Propylene glycol such as propylene glycol, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, and propylene glycol monobutyl ether; diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, and diethylene glycol diethyl ether. No Tylene glycols; Halogenated hydrocarbons such as trichloroethylene; Aromatic hydrocarbons such as toluene and xylene; Polarity such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methylacetamide, N-methylpyrrolidone Solvents are exemplified, and these may be used alone or as a mixture of two or more.

In the present invention, additives generally added to the resist composition as additives, such as surfactants, storage stabilizers, sensitizers, striation inhibitors, low molecular weight phenol compound derivatives and the like are compatible. Additives can be included. Specific examples of the low molecular weight phenol compound include monophenols such as p-phenylphenol and p-isopropylphenol; biphenol,
4,4′-dihydroxydiphenyl ether, 4,4 ′
-Dihydroxybenzophenone, bisphenol A (manufactured by Honshu Chemical Industry), bisphenol C (manufactured by Honshu Chemical Industry), bisphenol E (manufactured by Honshu Chemical Industry), bisphenol F (manufactured by Honshu Chemical Industry), bisphenol AP
(Honshu Chemical Co., Ltd.), bisphenol M (Mitsui Petrochemical Co., Ltd.), bisphenol P (Mitsui Petrochemical Co., Ltd.), bisphenol Z (Honshu Chemical Co., Ltd.), 1,1
-Bis (4-hydroxyphenyl) cyclopentane,
9,9-bis (4-hydroxyphenyl) fluorene,
1,1-bis (5-methyl-2-hydroxyphenyl)
Bisphenols such as methane and 3,5-dimethyl-4-hydroxybenzylphenol; 1,1,1-tris (4-hydroxyphenyl) methane, 1,1,1-tris (4-hydroxyphenyl) ethane, 1-bis (3-methyl-4-hydroxyphenyl) -1- (4-
Hydroxyphenyl) methane, 1,1-bis (2,5-
Dimethyl-4-hydroxyphenyl) -1- (2-hydroxyphenyl) methane, 1,1-bis (3,5-dimethyl-4-hydroxyphenyl) -1- (2-hydroxyphenyl) methane, 2,6- Bis (5-methyl-2-
(Hydroxybenzyl) -4-methylphenol, 2,6
-Bis (4-hydroxybenzyl) -4-methylphenol, 2,6-bis (3-methyl-4-hydroxybenzyl) -4-methylphenol, 2,6-bis (3,5
Trisphenols such as -dimethyl-4-hydroxybenzyl) -4-methylphenol, trisphenol-PA (manufactured by Honshu Chemical Industry), and trisphenol-TC (manufactured by Honshu Chemical Industry); 1,1,2,2 -Tetrakis (4-hydroxyphenyl) ethane, 1,1,2,2-
Tetrakis (3-methyl-4-hydroxyphenyl) ethane, 1,1,3,3- (4-hydroxyphenyl) propane, 1,1,5,5-tetrakis (4-hydroxyphenyl) pentane α, α, α ', Α'-tetrakis (4-hydroxyphenyl) -3-xylene, α, α,
α ', α'-tetrakis (4-hydroxyphenyl)-
4-xylene, α, α, α ′, α′-tetrakis (3-
Methyl-4-hydroxyphenyl) -3-xylene,
Examples include tetrakisphenols such as α, α, α ′, α′-tetrakis (3-methyl-4-hydroxyphenyl) -4-xylene. The amount of such a low-molecular phenol compound to be added depends on the composition, molecular weight, molecular weight distribution and the type and amount of other additives of the polymer, but the upper limit is usually 100 parts by weight based on 100 parts by weight of the polymer. Parts, preferably 60 parts by weight, and the lower limit is usually 0 parts by weight, preferably 3 parts by weight. Addition of such a low molecular weight phenol compound can improve characteristics such as sensitivity, resolution, and adhesion.

In the composition of the present invention, the polymer having the structural unit represented by the formula (1) has a solubility in the irradiated portion due to the action of the acid generated from the acid generator upon irradiation with radiation. Change. The composition of the present invention acts as a positive resist by using an alkaline developer.

The resist composition of the present invention generally uses an aqueous alkali solution as an alkali developing solution. Specific examples thereof include an aqueous solution of an inorganic alkali such as sodium hydroxide, potassium hydroxide, sodium silicate, and ammonia; ethylamine, propyl Aqueous solutions of primary amines such as amines;
Aqueous solutions of secondary amines such as diethylamine and dipropylamine; aqueous solutions of tertiary amines such as trimethylamine and triethylamine; aqueous solutions of alcoholamines such as diethylethanolamine and triethanolamine; tetramethylammonium hydroxide, tetraethylammonium hydroxide; An aqueous solution of a quaternary ammonium hydroxide such as trimethylhydroxymethylammonium hydroxide, triethylhydroxymethylammonium hydroxide, and trimethylhydroxyethylammonium hydroxide is exemplified. If necessary, a water-soluble organic solvent such as methanol, ethanol, propanol, and ethylene glycol, a surfactant, and a resin dissolution inhibitor may be added to the aqueous alkali solution.

A resist solution obtained by dissolving the resist composition of the present invention in a solvent is applied to the surface of a substrate such as a silicon wafer by a conventional method, and the solvent is dried and removed to form a resist film. As a coating method at this time, spin coating is particularly awarded. Exposure sources used for exposure for forming a pattern on the resist film thus obtained are far ultraviolet rays, KrF
An electron beam source such as an excimer laser beam, an X-ray, and an electron beam may be used. Further, it is preferable to perform a heat treatment (post-exposure bake) after the exposure because the sensitivity can be improved and stabilized.

[0022]

The present invention will be described more specifically with reference to Reference Examples, Synthesis Examples and Examples. In addition, part and% in each example
Are by weight unless otherwise specified.

(Synthesis Example 1) poly (1-methylcyclohexyl methacrylate) 1-methylcyclohexyl methacrylate 182.3
g (1.00 mol), 8.2 g (0.05 mol) of azobisisobutyronitrile, and 300 ml of dioxane were charged into a 1-liter flask, and charged at 80 ° C. under a nitrogen stream.
Stirring was performed for hours. The obtained reaction solution was poured into 10 liters of methanol, and the resulting precipitate was filtered. The obtained solid was dissolved in 400 ml of diethyl ether,
The mixture was poured into 1 liter of methanol, and the resulting precipitate was filtered (reprecipitation operation). After repeating this reprecipitation operation twice, it was dried to obtain 163.9 g of a polymer. This polymer is G
As a result of the PC analysis, Mw was 8,860.

(Synthesis Example 2) Poly (1-methylcyclopentyl methacrylate) Instead of 1-methylcyclohexyl methacrylate, 1-methylcyclopentyl methacrylate 168.2
g (1.00 mol) was used in the same manner as in Synthesis Example 1 to obtain 153.6 g of a polymer. As a result of GPC analysis, Mw of this polymer was 8,030.

(Synthesis Example 3) 1-methylcyclohexyl
Methacrylate / styrene copolymer 59.4 g (0.57 mol) of styrene, 72.9 g of 1-methylcyclohexyl methacrylate (0.40 m
ol), 8.2 g of azobisisobutyronitrile (0.0 g
5 mol) and 250 ml of dioxane were charged into a 1 liter flask, and stirred at 80 ° C. for 5 hours under a nitrogen stream. The obtained reaction solution was poured into 10 liters of methanol, and the resulting precipitate was filtered. The obtained solid was dissolved in 300 ml of diethyl ether, poured into 10 liters of methanol, and the resulting precipitate was filtered (reprecipitation operation). This reprecipitation operation was repeated twice, and then dried,
3.3 g of polymer were obtained. As a result of GPC analysis, this polymer was found to have Mw = 6,920. In addition, ¹ H-NMR
Further, the polymerization ratio of 1-methylcyclohexyl methacrylate / styrene was 48/52.

Synthesis Example 4 1-Methylcyclopentyl
Methacrylate / 4-hydroxystyrene 4-hydroxystyrene 36.6 g (0.30 mo
l), 1-methylcyclopentyl methacrylate 2
0.2 g (0.12 mol), azobisisobutyronitrile 1.0 g (0.006 mol), dioxane 100
ml into a 500 ml flask, and the
Stirring was performed at 15 ° C. for 15 hours. The obtained reaction solution was poured into 8 liters of toluene, and the resulting precipitate was filtered. The solid obtained was dissolved in 80 ml of diethyl ether, and 5
The mixture was poured into 1 liter of n-hexane, and the resulting precipitate was filtered (reprecipitation operation). After repeating this reprecipitation operation three times,
After drying, 34.1 g of a polymer was obtained. This polymer is G
As a result of PC analysis, Mw was 4,960. Also ¹
From 1 H-NMR, the polymerization ratio of 1-methylcyclopentyl methacrylate / 4-hydroxystyrene was 46/54.
Met.

(Synthesis Example 5) 1-methylcyclohexyl
Methacrylate / methyl methacrylate copolymer 1-methylcyclohexyl methacrylate 182.3
g to 1-methylcyclohexyl methacrylate 10
Except that 0.2 g (0.55 mol) and 45.1 g (0.45 mol) of methyl methacrylate were used, 134.4 g of a polymer was obtained in the same manner as in Synthesis Example 1. As a result of GPC analysis, this polymer was found to have Mw = 6,550. From ¹ H-NMR, the polymerization ratio of 1-methylcyclohexyl methacrylate / methyl methacrylate was 51/49.

(Synthesis Example 6) 1-methylcyclohexyl
Methacrylate / adamantyl methacrylate copolymer 1-methylcyclohexyl methacrylate 45.5 g
(0.25 mol), adamantyl methacrylate 5
5.0 g (0.25 mol), azobisisobutyronitrile 1.7 g (0.01 mol), dioxane 100 m
1 in a 1 liter flask, and at 80 ° C. under a nitrogen stream.
For 5 hours. The obtained reaction solution was poured into 10 liters of n-hexane, and the resulting precipitate was filtered. The obtained solid was dissolved in 400 ml of diethyl ether, poured into 7 liter of n-hexane, and the resulting precipitate was filtered (reprecipitation operation). This reprecipitation operation was repeated three times and then dried to obtain 90.5 g of a polymer. As a result of GPC analysis, Mw of this polymer was 6,890. From ¹ H-NMR, the polymerization ratio of 1-methylcyclohexyl methacrylate / adamantyl methacrylate was 54/46.

(Synthesis Example 7) 1-methylcyclohexyl
Methacrylate / 4-hydroxystyrene / adamantyl methacrylate copolymer 60 g (0.50 mol) of 4-hydroxystyrene, 1
-Methylcyclohexyl methacrylate 60.1 g
(0.33 mol), adamantyl methacrylate 2
4.9 g (0.22 mol), 1.7 g (0.01 mol) of azobisisobutyronitrile, 200 m of dioxane
1 in a 1 liter flask, and at 80 ° C. under a nitrogen stream.
For 15 hours. The obtained reaction solution was poured into 15 liters of xylene, and the resulting precipitate was filtered. The obtained solid was dissolved in 200 ml of diethyl ether,
The mixture was poured into 20 liters of n-hexane, and the resulting precipitate was filtered (reprecipitation operation). After repeating this reprecipitation operation three times, it was dried to obtain 83.5 g of a polymer. As a result of GPC analysis, this polymer was found to have Mw = 5,670. Also, from ¹ H-NMR, 1-methylcyclohexyl methacrylate / 4-hydroxystyrene / adamantyl
The polymerization ratio of methacrylate was 51/28/21.

(Synthesis Example 8) 1-ethylcyclohexyl
Methacrylate / 4-hydroxystyrene copolymer 29.4 g of 1-ethylcyclohexyl methacrylate instead of 1-methylcyclohexyl methacrylate
(0.15 mol), and 34.1 g of a polymer was obtained in the same manner as in Synthesis Example 4. This polymer is GP
As a result of C analysis, Mw was 5,470. In addition, ¹ H
From -NMR, the polymerization ratio of 1-ethylcyclohexyl methacrylate / 4-hydroxystyrene was 45/55.

Reference Example 1 Synthesis of t-butyl methacrylate / 4-hydroxystyrene copolymer Instead of 1-methylcyclohexyl methacrylate, 14.2 g (1.10 mo) of t-butyl methacrylate was used.
32.2 by the same method as in Synthesis Example 4 except that 1) was used.
g of polymer was obtained. As a result of GPC analysis,
Mw = 4,810. In addition, t is obtained from ¹ H-NMR.
The polymerization ratio of -butyl methacrylate / 4-hydroxystyrene was 42/58.

(Examples 1 to 8) 100 parts of the polymer obtained in Synthesis Examples 1 to 8, 5 parts of triphenylsulfonium triflate as a photoacid generator, and a fluorine-based surfactant 0.0
One part was dissolved in 440 parts of ethyl lactate, and filtered through a 0.1 μm polytetrafluoroethylene filter (manufactured by Millipore) to prepare a resist solution. After spin coating this resist solution on a silicon wafer,
By performing baking for 90 seconds, a resist film having a thickness of 1.0 μm was formed. This wafer was exposed using an excimer laser stepper (NA = 0.45) and a test mask. Next, after baking at 110 ° C. for 60 seconds, immersion development was performed for 1 minute in an aqueous solution of tetramethylammonium hydroxide to obtain a positive pattern.
Table 1 shows the sensitivity of these resist films and the resolution when a good pattern obtained by optimizing exposure was shown.

[0033]

[Table 1]

Example 9 A performance test was carried out on the polymer obtained in Synthesis Example 4 in the same manner as in Example 4 except that the photoacid generator was 5 parts of diphenyliodonium triflate.
As a result, the sensitivity was 11 mJ / cm ² and the resolution was 0.25.
μm.

Example 10 The same procedure as in Example 4 was carried out except that the photoacid generator of the polymer obtained in Synthesis Example 4 was changed to 10 parts of hydroquinone monotosylate and the baking conditions after exposure were changed to 110 ° C. and 60 seconds. A performance test was performed. As a result, the sensitivity was 34 mJ / cm ² and the resolution was 0.35 μm.
Met.

(Example 11) Except that 10 parts of bisphenol A was further added to the resist composition used in Example 4,
The same performance test as in Example 4 was performed. As a result, the sensitivity was 9 mJ / cm ² and the resolution was 0.25 μm.

(Example 12) Using the resist material of Example 4, the time from exposure to baking was 15 minutes, 30 minutes, and 6 minutes.
The pattern shape was examined by changing it to 0 minutes and 120 minutes.
In each case, good patterns were obtained.

Comparative Example 1 A resist solution was prepared for the polymer obtained in Reference Example 1 in the same manner as in Example 4, and the same performance test as in Example 4 was performed. As a result, the sensitivity was 9
mJ / cm ² , and the resolution was 0.275 μm. Using this resist material, the time from exposure to baking is 15
The pattern shape was examined by changing the pattern time to 30 minutes, 60 minutes, and 120 minutes. After 15 minutes, the shape was slightly deteriorated, and the degree of deterioration became more severe as time passed. After 60 minutes, the pattern could no longer be formed. Table 2 shows data of Example 12 and Comparative Example 1.

[0039]

[Table 2]

As can be seen from Examples 1 to 11, high sensitivity and resolution were obtained by using the polymer of the present invention.
Also, from Comparative Example 1, it was found that the resist composition containing the polymer of the present invention was excellent in stability.

[0041]

As described above, according to the present invention, a resist material excellent in resist characteristics such as sensitivity, resolution and stability and suitable for lithography using a short ultraviolet ray or KrF excimer laser light can be obtained. The resist composition of the present invention is particularly suitable as a positive resist for fine processing of semiconductor devices.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03F 7/039 G03F 7/004 G03F 7/38 H01L 21/027

Claims (3)

(57) [Claims] 1. The compounds of the general formulas (1), (2) and (3) Embedded image Embedded image (In the formulas (1) to (3), R ^{1 to} R ³ are each independently a hydrogen atom, a substitutable alkyl group having 1 to 4 carbon atoms, a halogen atom, a cyano group, or a nitro group, and R ⁴ is a straight-chain. R ⁵ and R ⁶ are each independently a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxyl group, a carboxyl group, Straight-chain, branched or cyclic C1-C8 substitutable alkyl group, straight-chain, branched or cyclic C1-C8
A substituted aryl group having 6 to 12 carbon atoms, a substituted aralkyl group having 7 to 14 carbon atoms,
⁷ is a linear, branched or cyclic C1-C8 substitutable alkyl group, or a linear, branched or cyclic C1-C8 substitutable alkenyl group. R ^{8 to} R ¹¹ are a hydrogen atom, a halogen atom, or a substitutable alkyl group having 1 to 4 carbon atoms, at least one of which is a hydrogen atom. A is a single bond or a divalent substitutable organic group. The unit ratios represented by the formulas (1), (2) and (3) are represented by k, m and n, respectively, and k +
m + n = 1, 0 <k ≦ 1, 0 ≦ m <1, 0 ≦ n <
It is one. After exposing a resist film containing a polymer having the structural unit represented by the formula (1) and a radiation-sensitive component that generates an acid upon irradiation with activating radiation, followed by a heat treatment after a lapse of 15 to 120 minutes. Pattern forming method. 2. Formulas (1), (2) and (3) Embedded image Embedded image (In the formulas (1) to (3), R ^{1 to} R ³ are each independently a hydrogen atom, a substitutable alkyl group having 1 to 4 carbon atoms, a halogen atom, a cyano group, or a nitro group, and R ⁴ is a straight-chain. R ⁵ and R ⁶ are each independently a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxyl group, a carboxyl group, Straight-chain, branched or cyclic C1-C8 substitutable alkyl group, straight-chain, branched or cyclic C1-C8
A substituted aryl group having 6 to 12 carbon atoms, a substituted aralkyl group having 7 to 14 carbon atoms,
⁷ is a linear, branched or cyclic C1-C8 substitutable alkyl group, or a linear, branched or cyclic C1-C8 substitutable alkenyl group. R ^{8 to} R ¹¹ are a hydrogen atom, a halogen atom, or a substitutable alkyl group having 1 to 4 carbon atoms, at least one of which is a hydrogen atom. A is a single bond or a divalent substitutable organic group. The unit ratios represented by the formulas (1), (2) and (3) are represented by k, m and n, respectively, and k +
m + n = 1, 0 <k ≦ 1, 0 ≦ m <1, 0 ≦ n <
It is one. A resist composition comprising a polymer having a polymerization average molecular weight of 4,960 to 8,860 having a structural unit represented by formula (1) and a radiation-sensitive component that generates an acid upon irradiation with activating radiation. 3. The resist according to claim 2, wherein the radiation-sensitive component that generates an acid upon irradiation with activating radiation is a compound selected from the group consisting of triphenylsulfonium triflate, diphenyliodonium triflate and hydroquinone monotosylate. Composition.