JPH08202039A - Radiation sensitive resin composition - Google Patents

Abstract

PURPOSE: To provide a radiation sensitive resin composition especially superior in resolution and pattern form and also superior in sensitivity and developability, and yet good in contrast and heat resistance and the like, and useful as a chemically amplifiable resist. CONSTITUTION: The radiation sensitive resin composition contains a polymer (A) having repeating units each represented by the formula (in which R<1> is a substituted methyl or ethyl group, a silyl or germyl or alkoxycarbonyl group; R<2> is a -OR<3> or -NR<4> R<5> group; and each of R<3> -R<5> is, independently, an H atom or a straight or branched alkyl, aralkyl, aryl, substituted methyl, substituted ethyl, silyl, germyl, or alkoxycarbonyl group), and at least one radiation sensitive acid generator selected from imidosulfonate derivatives.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation-sensitive resin composition, and more specifically, it is useful as a resist suitable for fine processing using various kinds of radiation such as ultraviolet rays, far ultraviolet rays, X-rays or charged particle beams. Radiation sensitive resin composition.

[0002]

2. Description of the Related Art In the field of microfabrication represented by the manufacture of integrated circuit devices, miniaturization of the processing size in lithography is rapidly progressing in order to obtain a higher degree of integration of integrated circuits. The development of a lithography process capable of stably performing high-precision fine processing with a line width of 0.5 μm or less has been strongly promoted. However, conventional visible light (wavelength 700-400n
It is difficult to form such a fine pattern with high accuracy by the method using m) or near-ultraviolet light (wavelength 400 to 300 nm). Therefore, it is possible to achieve a wider depth of focus, and it is effective for the miniaturization of design rules. Short wavelength (wavelength 3
A lithographic process using radiation of 100 nm or less) has been proposed.

As a lithographic process using such short wavelength radiation, a KrF maxi laser (wavelength 248 nm) and an ArF maxi laser (wavelength 1) are used.
X-rays such as deep ultraviolet rays (93 nm), synchrotron radiation, etc.
A method using a charged particle beam such as a beam or an electron beam has been proposed. As a high resolution resist for such short wavelength radiation, "Chemically Amplified Resist" was proposed by International Business Machines (IBM). Currently, improvement and development of this chemically amplified resist is energetically pursued. Is being promoted.

In such a chemically amplified resist, an acid is generated from a radiation-sensitive acid generator contained by irradiation with radiation (hereinafter referred to as "exposure"), and the acid acts as a catalyst to cause the acid in the resist film. In order to form a pattern, a chemical reaction (for example, change in polarity, cleavage of chemical bond, cross-linking reaction, etc.) is caused and the solubility in the developing solution changes in the exposed portion.

Among the chemically amplified resists having relatively good resist performance, the alkali-affinity group in the alkali-soluble resin is protected with a t-butyl ester group or a t-butoxycarbonyl group as a resin component. Resin (see, for example, Japanese Patent Publication No. 27660/1990), resin in which an alkali-affinity group in an alkali-soluble resin is protected by a silyl group (for example, Japanese Patent Publication No. 3-44290), (meth)
A resin containing an acrylic acid component (for example, Japanese Patent Publication No. 4-39
No. 665), and a resist using a mixture of the above resin and a phenolic novolac resin (see, for example, JP-A-63-250642). However, it has been pointed out that each of these chemically amplified resists has its own problems and various difficulties are involved in putting it into practical use.

That is, when a resin having a t-butyl ester group or a t-butoxycarbonyl group is used, a gas component such as isobutene gas or carbon dioxide gas is released by a chemical reaction due to the catalytic action of an acid generated by exposure.
Volume contraction occurs in the exposed portion, and as a result, the pattern shape is easily distorted, and it is difficult to form a highly accurate resist pattern. In addition, when a resin having a silyl group is used, the pattern shape is generally good, but there is a drawback that it is inferior in releasability from the substrate as compared with a resist having no silyl group. Further, when a (meth) acrylic acid type resin is used, the adhesiveness between the resist and the substrate such as silicon is insufficient, and when an aromatic type resin (eg phenol novolac resin etc.) is used as the constituent resin of the resist. There is a problem that dry etching resistance is lower than that of the above.

In order to solve such a problem in the chemically amplified resist, a resist using a resin containing both a phenol skeleton and a (meth) acrylic acid ester unit has been proposed in recent years and has been attracting attention ( For example, JP-A-4
(See No. 251259, No. 5-181279, No. 5-113667). However, although dry etching resistance is improved with these resists, there is a problem in terms of pattern shape because it is difficult to obtain a good rectangular pattern, and resolution, developability, etc. are insufficient, and therefore, as a chemically amplified resist. Further improvement is required from the viewpoint of comprehensive characteristics.

[0008]

SUMMARY OF THE INVENTION In view of such a situation, the present invention has been found as a result of further detailed study of a resin component constituting a chemically amplified resist. An object of the present invention is to provide a novel radiation-sensitive resin composition that is effectively sensitive to various radiations such as ultraviolet rays, far ultraviolet rays, X-rays and charged particle beams. Another object of the present invention is to provide a radiation-sensitive resin composition which does not cause volume shrinkage, peeling failure from a substrate, or adhesion failure. Still another object of the present invention is a radiation-sensitive resin composition which is particularly useful as a chemically amplified resist having excellent resolution and pattern shape, excellent residual film rate, sensitivity and developability, and also good contrast and heat resistance. To provide things. Further objects and advantages of the present invention will be apparent from the following description.

[0009]

According to the present invention, the above objects and effects of the present invention are: (a) the following formula (1)

[0010]

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(Wherein R ¹ represents a substituted methyl group, a substituted ethyl group, a silyl group, a germyl group or an alkoxycarbonyl group, and R ² represents —OR ³ or NR ⁴ R ⁵ (provided that R 2
³ , R ⁴ and R ⁵ are the same or different and each represents a hydrogen atom, a linear alkyl group, a cyclic alkyl group, an aralkyl group, an aryl group, a substituted methyl group, a substituted ethyl group, a silyl group, a germyl group or an alkoxycarbonyl group). And a radiation-sensitive acid generator selected from at least one or more imidosulfonate derivatives, which is a radiation-sensitive resin composition. . The polymer which is the component (a) used in the present invention (hereinafter referred to as "polymer (A)") contains the repeating unit represented by the above formula (1).

Examples of the substituted methyl group represented by R ¹ in the above formula (1) include methoxymethyl group, methylthiomethyl group, methoxyethoxymethyl group, tetrahydropyranyl group, tetrahydrothiopyranyl group, tetrahydrofuranyl group and tetrahydro. Thiofuranyl group, benzyloxymethyl group, phenacyl group, bromophenacyl group, methoxyphenacyl group, α-methylphenacyl group, cyclopropylmethyl group, cyclopentyl group, cyclohexyl group, benzyl group, triphenylmethyl group, diphenylmethyl group , Bromobenzyl group, nitrobenzyl group, methoxybenzyl group, piperonyl group, furfuryl group and the like, and examples of the substituted ethyl group include 1-methoxyethyl group, 1-ethoxyethyl group, isopropyl group, t-butyl group, 1, 1-dimethylpropyl group, etc. Examples of silyl groups include trimethylsilyl group, triethylsilyl group, t-butyldimethylsilyl group, isopropyldimethylsilyl group, phenyldimethylsilyl group, and examples of germyl groups include trimethylgermyl group, triethylgermyl group, Examples thereof include an isopropyldimethylgermyl group, a t-butyldimethylgermyl group, and a phenyldimethylgermyl group, and examples of the alkoxycarbonyl group include a methoxycarbonyl group, an ethoxycarbonyl group, and a t-butoxycarbonyl group.

In the above formula, examples of the linear alkyl group for R ³ , R ⁴ and R ⁵ include a methyl group, an ethyl group, an n-propyl group and an n-butyl group. Examples of the cyclic alkyl group include a cyclopentyl group and a cyclohexyl group. Examples of the aralkyl group include a benzyl group, an α-methylbenzyl group, a diphenylmethyl group and a trityl group. Examples of the aryl group include a phenyl group, a naphthyl group, a tolyl group and the like. Examples of the substituted methyl group, the substituted ethyl group, the silyl group, the germyl group or the alkoxycarbonyl group include the substituted methyl group, the substituted ethyl group exemplified in R ¹ .
A silyl group, a germyl group or an alkoxycarbonyl group can be mentioned.

The polymer (A) in the present invention may be composed of only the repeating unit represented by the above formula (1) or may have other repeating units. Examples of other repeating units here include the following formula (2)

[0015]

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A repeating unit represented by the following formula (3)

[0017]

[Chemical 4]

A repeating unit represented by the following formula (4)

[0019]

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A double unit of a compound having a repeating unit represented by: and a double bond such as maleic anhydride, maleic acid, fumaric acid, fumaronitrile, acrylamide, acrylonitrile, vinylpyridine, vinylpyrrolidone, vinylimidazole or vinylaniline. A repeating unit in which the bond is cleaved can be mentioned as a preferable example.
Of these, particularly preferred repeating units are styrene,
It is a repeating unit in which the double bond of vinylphenol, isopropenylphenol and maleic anhydride is cleaved.

In the polymer (A) of the present invention, the preferable ratio of the repeating unit represented by the above formula (1) cannot be unconditionally defined depending on the kind of other repeating units, but it is usually 20 of the total number of repeating units. % Or more, preferably 25% or more, particularly preferably 30% or more. If it is less than 20%, the effect is not sufficient for forming a resist pattern.

The polystyrene-reduced weight average molecular weight (hereinafter referred to as "Mw") of the polymer (A) in the present invention is 1,000 to 50,000, and particularly preferably 1,500 to 40,000.

The method for producing the polymer containing the repeating unit represented by the formula (1) in the present invention is, for example, a maleic anhydride moiety of a maleic anhydride copolymer such as poly (styrene-maleic anhydride). After hydrolyzing the carboxylic acid to dicarboxylic acid, a method of substituting a part or all of the hydrogen of the resulting carboxylic acid with a substituted methyl group, a substituted ethyl group, a silyl group, a germyl group or an alkoxycarbonyl group, or an anhydride of the copolymer. After reacting a maleic acid moiety with a hydroxy compound or an amine to form a half ester or half amide, a part or all of the hydrogen of the resulting carboxylic acid is substituted with a methyl group, a substituted ethyl group, a silyl group, a germyl group or an alkoxy. Examples thereof include a method of substituting with a carbonyl group.

Further, hydrogen of carboxylic acid of fumaric acid or maleic acid is substituted with a methyl group, a substituted ethyl group, a silyl group,
A method of copolymerizing a monomer substituted with a germyl group or an alkoxycarbonyl group with a monomer such as vinylphenol, or after obtaining a half ester or half amide by reacting maleic anhydride with a hydroxy compound or amines, Examples thereof include a method in which a monomer in which hydrogen of the generated carboxylic acid is substituted with a substituted methyl group, a substituted ethyl group, a silyl group, a germyl group or an alkoxycarbonyl group is copolymerized with a monomer such as vinylphenol.

The polymer (A) in the present invention can also be used as a mixture with other polymers. Here, specific examples of the other polymer include a repeating unit in which a double bond of a compound having a double bond such as hydroxystyrene, isopropenylphenol, acrylic acid, methacrylic acid, fumaric acid or maleic acid is cleaved. Those having are preferred.

The radiation-sensitive acid generator which is the component (b) is a compound which generates an acid upon exposure, and the radiation-sensitive acid generator used in the present invention is at least one or more imidosulfonate derivatives. It is characterized by containing a compound selected from

Preferred examples of the compound selected from the imidosulfonate derivatives include N- (trifluoromethylsulfonyloxy) succinimide and N-.
(Trifluoromethylsulfonyloxy) phthalimide, N- (trifluoromethylsulfonyloxy) diphenylmaleimide, N- (trifluoromethylsulfonyloxy) bicyclo [2.2.1] hept-5-ene-
2,3-dicarboximide, N- (trifluoromethylsulfonyloxy) -7-oxabicyclo [2.2.1]
Hept-5-ene-2,3-dicarboximide, N-
(Trifluoromethylsulfonyloxy) naphthylimide, N- (trifluoromethylsulfonyloxy) bicyclo [2.2.1] heptane-5,6-oxy-2,3-dicarboximide,

N- (camphorsulfonyloxy) succinimide, N- (camphorsulfonyloxy) phthalimide, N- (camphorsulfonyloxy) diphenylmaleimide, N- (camphorsulfonyloxy)
Bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (camphorsulfonyloxy)-
7-oxabicyclo [2.2.1] hept-5-ene-
2,3-dicarboximide, N- (camphorsulfonyloxy) naphthylimide, N- (camphorsulfonyloxy) bicyclo [2.2.1] heptane-5,6-oxy-2,3-dicarboximide, N -(4-methylphenylsulfonyloxy) succinimide, N- (4-
Methylphenylsulfonyloxy) phthalimide, N-
(4-Methylphenylsulfonyloxy) diphenylmaleimide, N- (4-methylphenylsulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-
Dicarboximide, N- (4-methylphenylsulfonyloxy) -7-oxabicyclo [2.2.1] hept-
5-ene-2,3-dicarboximide, N- (4-methylphenylsulfonyloxy) naphthylimide, N-
(4-methylphenylsulfonyloxy) bicyclo [2.2.1] heptane-5,6-oxy-2,3-dicarboximide,

N- (2-trifluoromethylphenylsulfonyloxy) succinimide, N- (2-trifluoromethylphenylsulfonyloxy) phthalimide,
N- (2-trifluoromethylphenylsulfonyloxy) diphenylmaleimide, N- (2-trifluoromethylphenylsulfonyloxy) bicyclo [2.2.1]
Hept-5-ene-2,3-dicarboximide, N-
(2-trifluoromethylphenylsulfonyloxy)
-7-Oxabicyclo [2.2.1] hept-5-ene-
2,3-dicarboximide, N- (2-trifluoromethylphenylsulfonyloxy) naphthylimide, N-
(2-trifluoromethylphenylsulfonyloxy)
Bicyclo [2.2.1] heptane-5,6-oxy-2,3
-Dicarboximide and the like can be mentioned.

In the present invention, the above-mentioned radiation-sensitive acid generator is usually used per 100 parts by weight of the polymer (A),
It is used in a proportion of 0.1 to 20 parts by weight, particularly preferably 0.5 to 10 parts by weight. These radiation-sensitive acid generators are used alone or in admixture of two or more. Further, the radiation-sensitive acid generator used in the present invention may include a compound that generates an acid upon exposure, in addition to the imidosulfonate derivative. Examples of such a compound include an onium salt, a halogen-containing compound, a diazoketone compound, a sulfone compound, a sulfonic acid compound, a nitrobenzyl compound and the like, and specific examples include the compounds shown below.

Onium salts: Iodonium salts, sulfonium salts, phosphonium salts, diazonium salts, ammonium salts and the like can be mentioned. Preferably, the following formula

[0032]

[Chemical 6]

Compounds represented by the following are preferable, and triphenylsulfonium triflate, triphenylsulfonium hexafluoroantimonate, diphenyliodonium triflate and diphenyliodonium hexafluoroantimonate are particularly preferable.

Halogen-containing compounds: haloalkyl group-containing hydrocarbon compounds, haloalkyl group-containing heterocyclic compounds, and the like. Preferably, the following formula

[0035]

[Chemical 7]

The compound represented by the formula (1), particularly preferably 1,1-bis (4-chlorophenyl) -2,2,2-
Examples include trichloroethane, phenyl-bis (trichloromethyl) -s-triazine, naphthyl-bis (trichloromethyl) -s-triazine and the like.

Diazoketone compound: 1,3-diketo-2
-A diazo compound, a diazobenzoquinone compound, a diazonaphthoquinone compound, etc. can be mentioned. Preferably, the following formula

[0038]

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The compound represented by the formula (1), particularly preferably 1,2-naphthoquinonediazide-4-sulfonyl chloride, 1,2-naphthoquinonediazide-4-sulfone of 2,3,4,4'-tetrahydroxybenzophenone Acid ester, 1,2-naphthoquinonediazide-4-sulfonic acid ester of 1,1,1-tris (4-hydroxyphenyl) ethane, 1,1-bis (3,5-dimethyl-2-
1,2-naphthoquinonediazide-4-sulfonic acid ester of hydroxyphenyl) -1- [4- (4-hydroxybenzyl) phenyl] ethane.

Sulfone compound: β-ketosulfone, β-
Examples thereof include sulfonyl sulfone and bissulfonyl diazomethane. Preferably, the following formula

[0041]

[Chemical 9]

The compound represented by the formula (4) is particularly preferably 4-trisphenacylsulfone, mesitylphenacylsulfone, bis (phenylsulfonyl) methane, bis (cyclohexylsulfonyl) diazomethane and the like.

Nitrobenzyl compounds: Nitrobenzyl sulfonate compounds, dinitrobenzyl sulfonate compounds and the like can be mentioned. Preferably, the following formula

[0044]

[Chemical 10]

Compounds represented by the following formulas are particularly preferred: 2-nitrobenzyl tosylate, 2,4-dinitrobenzyl tosylate, 4-nitrobenzyl-9,10-
Examples thereof include diethoxyanthracene-2-sulfonate.

Sulfonic acid compounds: alkyl sulfonates, haloalkyl sulfonates, aryl sulfonates, imino sulfonates and the like can be mentioned, preferably the following formula

[0047]

[Chemical 11]

The compound represented by the formula (3) is particularly preferable, and benzoin tosylate and tris triflate of pyrogallol are preferable. Of these radiation-sensitive acid forming agents, onium salts and sulfone compounds are preferable.

Other Components (Component (C)) The composition of the present invention is a compound capable of decomposing by the action of an acid to accelerate the dissolution in a developing solution (hereinafter, referred to as “dissolution control agent” ) , if necessary. That is)) can be contained. These dissolution control agents have, for example, the following formula

[0050]

[Chemical 12]

[0051]

[Chemical 13]

Examples thereof include compounds represented by:

Examples of the substituted methyl group, substituted ethyl group, silyl group, germyl group or alkoxycarbonyl group for R ^{45 to} R ⁴⁷ include substituted methyl group, substituted ethyl group, silyl group, germyl group or alkoxycarbonyl for R ^1. The same groups as mentioned as examples of groups can be mentioned.

The blending amount of the dissolution control agent is such that the polymer (A) 10
It is usually 100 parts by weight or less, preferably 10 to 50 parts by weight, per 0 parts by weight.

The composition of the present invention further comprises, if desired,
Various additives can be added. Examples of such additives include acid diffusion control agents and surfactants for improving coatability, striation, developability of a radiation-irradiated portion after forming a dry coating film, and the like.

The acid diffusion control agent has a function of controlling the diffusion phenomenon of the acid generated from the radiation-sensitive acid generator upon exposure in the resist film and suppressing an undesired chemical reaction in the unexposed area. is there. By using the acid diffusion control agent, it is possible to further improve the pattern shape, in particular, the degree of the generation of the fart in the pattern upper layer portion, the dimensional fidelity with respect to the mask dimension, and the like.

As such an acid diffusion control agent, a nitrogen-containing organic compound whose basicity does not change by exposure or heating is preferable, and specific examples thereof include ammonia, hexylamine, heptylamine, octylamine, nonylamine,
Decylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, trimethylamine, triethylamine, tripropylamine, tributylamine, tripentylamine, trihexylamine,
Triheptylamine, trioctylamine, trinonylamine, tridecylamine, aniline, N-methylaniline, N, N-dimethylaniline, 2-methylaniline, 3-methylaniline, 4-methylaniline, 4-nitroaniline, 1-naphthylamine, 2-naphthylamine, diphenylamine, ethylenediamine, tetramethylenediamine, hexamethylenediamine, pyrrolidone,
Piperidine, imidazole, 4-methylimidazole,
4-methyl-2-phenylimidazole, thiabendazole, pyridine, 2-methylpyridine, 4-methylpyridine, 2-ethylpyridine, 4-ethylpyridine, 1-
Methyl-4-phenylpyridine, 2- (1-ethylpropyl) pyridine, nicotinamide, dibenzoylthiamine, riboflavin tetrabutyrate, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl ether, 4,
4'-diaminobenzophenone, 4,4'-diaminodiphenylamine, 2,2-bis (4-aminophenyl) propane, 2- (3-aminophenyl) -2- (4-aminophenyl) propane, 2- (4 -Aminophenyl)-
2- (3-hydroxyphenyl) propane, 2- (4-
Aminophenyl) -2- (4-hydroxyphenyl) propane, 1,4-bis [1- (4-aminophenyl)-
1-methylethyl] benzene, 1,3-bis [1- (4
-Aminophenyl) -1-methylethyl] benzene, dimethyl succinate-1- (2-hydroxyethyl) -4-
Hydroxy-2,2,6,6-tetramethylpiperidine polycondensate, poly [{6- (1,1,3,3-tetramethylbutyl) imino-1,3,5-triazine-2,4-diyl } {(2,2,6,6-Tetramethyl-4-piperidiyl) imino} hexamethylene {(2,2,6,6-tetramethyl-4-piperidiyl) imino}], 2- (3,5
-Di-t-butyl-4-hydroxybenzyl) -2-n
Bis (1,2,2,6,6-pentamethyl-4-piperidiyl) -butylmalonate and the like can be mentioned. These acid diffusion control agents may be used alone or in admixture of two or more.

The mixing ratio of the acid diffusion inhibitor in the present invention is usually 0.00 per 100 parts by weight of the polymer (A).
It is 1 to 10 parts by weight, preferably 0.005 to 5 parts by weight. In this case, if the amount of the acid diffusion controlling agent used is less than 0.001 part by weight, the pattern shape and dimensional fidelity may be lowered depending on the process conditions, and if it exceeds 10 parts by weight, the sensitivity and the resist property may be reduced. The developability of the exposed area tends to decrease. As the surfactant, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene octylphenol ether,
Polyoxyethylene nonylphenol ether, polyethylene glycol dilaurate, polyethylene glycol distearate, commercially available products such as Ftop EF301, EF303, EF352 (manufactured by Tochem Products), Megafax F171, F173 (manufactured by Dainippon Ink and Chemicals, Inc.) , Florard FC430, FC43
1 (manufactured by Sumitomo 3M Limited), Asahi Guard AG71
0, Surflon S-382, SC101, SC102,
SC103, SC104, SC105, SC106 (manufactured by Asahi Glass Co., Ltd.), organosiloxane polymer KP34
1 (manufactured by Shin-Etsu Chemical Co., Ltd.), an acrylic acid-based or methacrylic acid-based (co) polymer, Polyflow No. 75, N
O.95 (trade name, manufactured by Kyoeisha Oil and Fat Chemical Co., Ltd.) and the like are used.

The content of the surfactant is usually 2 parts by weight or less per 100 parts by weight of the total amount of the polymer (A) and the radiation-sensitive acid forming agent. Examples of other additives include azo compounds, antihalation agents, adhesion aids, storage stabilizers and defoamers.

The composition of the present invention comprises the above-mentioned polymer (A).
And a radiation-sensitive acid forming agent, and optionally a dissolution inhibitor, an acid diffusion controller or various additives, which are prepared by dissolving them in a required amount in a solvent. Examples of the solvent used at this time include ethylene glycol-
Rumonomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether,
Ethylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, diethylene glycol dibutyl ether, methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol monomethyl ether acetate , Propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate,
Toluene, xylene, methyl ethyl ketone, cyclohexanone, methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutanoate , 3-methoxybutyl acetate, 3-methyl-3
-Methoxybutyl acetate, 3-methyl-3-methoxybutyl propionate, 3-methyl-3-methoxybutyl butyrate, ethyl acetate, butyl acetate, methyl acetoacetate, ethyl acetoacetate, methyl-3-methoxypropionate , Ethyl-3-ethoxypropionate, N
-Methylpyrrolidone, N, N-dimethylformamide,
Examples thereof include dimethylacetamide.

Further, these solvents may be added to benzyl ethyl ether, dihexyl ether, diethylene glycol monomethyl ether, diethylene glycol-if necessary.
Lumonoethyl ether, acetonylacetone, isophorone, caproic acid, caprylic acid, 1-octanol, 1-
Nonanol, benzyl alcohol, benzyl acetate, ethyl benzoate, diethyl oxalate, diethyl maleate,
γ-butyrolactone, ethylene carbonate, propylene carbonate,
A high boiling point solvent such as phenyl cellosolve acetate can also be added.

The composition of the present invention is applied in the form of the above solution onto a substrate such as a silicon wafer and dried to form a resist film for use. In this case, for example, the composition of the present invention may be applied to the substrate at a solid concentration of 5
It is carried out by dissolving in the above-mentioned solvent so as to be 50% by weight, filtering, and then applying this by spin coating, flow coating, roll coating or the like.

The formed resist film is partially exposed to form a fine pattern. The radiation used is not particularly limited, and for example, ultraviolet rays such as excimer laser, X-ray such as synchrotron radiation, and charged particle beam such as electron beam are used depending on the type of the radiation-sensitive acid generator used. To be The irradiation conditions such as the exposure amount are appropriately determined according to the composition of the composition, the type of each addition amount, and the like.

In the present invention, it is preferable to carry out heating after exposure in order to improve the apparent sensitivity of the resist. The heating conditions vary depending on the composition of the composition, the type of each additive, etc., but are usually 30 to 200 ° C.,
It is preferably 50 to 150 ° C.

The developer used in the subsequent development is, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, in order to obtain a positive pattern. n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine, dimethylethanolamine, triethano-
Lumine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, pyrrol, piperidine, 1,8-diazabicyclo [5.4.0] 7-undecene, 1,5-diazabicyclo [4.3.0] 5-nonene It is possible to use an alkaline aqueous solution obtained by dissolving the above.

Further, a water-soluble organic solvent, for example, an alcoholic solution such as methanol or ethanol, or an alkaline aqueous solution to which a surfactant is appropriately added, can be used as the developer. Further, as the developing solution, for example, chloroform, benzene or the like can be used, and in this case, a negative pattern can be obtained.

[0067]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.
Here, Mw and polystyrene-equivalent number average molecular weight (hereinafter referred to as “Mn”), the ratio Mw / Mn thereof, and evaluation of each resist were performed in the following manner.

Mw and Mn, Mw / Mn Tosoh Corp. GPC column (2 G2000H _XL ,
G3000H _XL 1 piece, G4000H _XL 1 piece)
The flow rate was 1.0 ml / min, the elution solvent was tetrahydrofuran, and the column temperature was 40 ° C.

Sensitivity After exposure of a resist film formed on a silicon wafer, immediately post-exposure baking was performed, followed by development with an alkali developing solution, washing with water, and drying to form a resist pattern. The exposure amount for forming a line-and-space pattern (1L1S) of 5 μm with a line width of 1: 1 was taken as the optimum exposure amount, and the sensitivity was evaluated by this optimum exposure amount.

Resolution The minimum dimension (μm) of the resist pattern resolved when exposed with the optimum exposure amount was taken as the resolution.

1 L1 with a line width of 0.3 μm formed on a patterned silicon wafer
The rectangular cross section of S is observed using a scanning electron microscope,
If the pattern shape does not exist in the vicinity of the substrate, there is no pattern head overhang, and the pattern head is not thin, the pattern shape is “good”. If the pattern shape does not satisfy at least one of these conditions, the pattern shape is It was determined to be “bad”. Further, the angle formed by the substrate and the pattern side surface of the 1 L 1 S rectangular cross section of 0.3 μm was measured, and the taper angle was measured. A taper angle of 90 degrees was the best, and a taper angle of more than 90 degrees and a reverse taper shape was regarded as a defect.

Residual film ratio The ratio (%) of the thickness of the resist pattern after development to the thickness of the resist pattern before development is defined as the residual film ratio. When the value is 97% or more, the residual film ratio is "good", 90%. If it is 97% or more and less than 90%, it is defined as "OK", and if it is less than 90%, it is defined as "bad".

Developability The resist pattern after development was observed using a scanning electron microscope to evaluate the presence or absence of scum after exposure and the extent of development residual.

Synthesis of Polymer (A) Synthesis Example 1 Styrene-maleic anhydride copolymer (copolymerization ratio 3: 1)
102.5 g (1 mol) and benzyl alcohol 29.7 g
(0.28 mol) was reacted with dioxane for 5 hours to obtain poly (styrene-benzyl maleate). In addition to this polymer, 3,4-dihydro-2H-
Pyrane (23.1 g, 0.28 mol) was added to dioxane in the presence of a catalytic amount of p-toluenesulfonic acid pyridinium salt.
Allowed to react for hours. After the reaction, the reaction solution was dropped into a large amount of methanol-water to solidify the polymer, and unreacted benzyl alcohol and 3,4-dihydro-2H-pyran were removed to obtain a white polymer powder. . This polymer contains a repeating unit in which R ¹ in the formula (1) is a tetrahydropyranyl group and R ² is a benzyloxy group. As a result of ¹³ C-NMR measurement, the ratio of the repeating unit represented by the formula (1) was 25% of the total number of repeating units of the polymer, and the Mw of the polymer was 12,4.
00 and Mw / Mn were 1.66. This polymer
Let it be a polymer (a-1).

Synthesis Example 2 Di-t-butyl fumarate (68 g, 0.3 mol) and p-vinylphenol (84 g, 0.7 mol) were dissolved in propylene glycol monomethyl ether (180 g) to prepare 2,2 '.
After adding 8 g of -azobis (4-methoxy-2,4-dimethylvaleronitrile), polymerization was carried out for 10 hours while maintaining the reaction temperature at 80 ° C under a nitrogen atmosphere. After polymerization,
The reaction solution was dropped into a large amount of water and solidified to obtain a white polymer powder. This polymer contains a repeating unit in which R ¹ and R ² in the formula (1) are t-butoxy groups. As a result of ¹³ C-NMR measurement, the ratio of the repeating unit represented by the formula (1) was 30% of the total repeating units of the polymer, and the Mw of the polymer was 25,400, Mw /
Mn was 1.66. This polymer is referred to as a polymer (
2).

Synthesis Example 3 Di-l-ethoxyethyl fumarate (105 g, 0.5 mol) and p-vinylphenol (60 g, 0.5 mol) were dissolved in propylene glycol monomethyl ether (180 g). To give a white polymer powder. In this polymer, R ¹ and R ² in the formula (1) are 1-
It contains a repeating unit which is an ethoxyethyloxy group. As a result of ¹³ C-NMR measurement, the ratio of the repeating unit represented by the formula (1) was 50% of the total repeating units of the polymer, and the Mw of the polymer was 32,400, Mw / M.
n was 1.66. This polymer is referred to as a polymer (
3).

Comparative Synthesis Example 1 A solution of 12 g of poly (p-vinylphenol) (commercially available from Maruzen Petrochemical Co., Ltd.) and 5 g of triethylamine in 50 g of dioxane was added to di-t-butyl carbonate under stirring. After adding 11 g and reacting at room temperature for further 6 hours, oxalic acid was added to neutralize triethylamine.
Then, the reaction solution was dropped into a large amount of water to solidify the polymer, and the solidified polymer was purified several times with pure water to obtain a white polymer powder (yield 90%). The polymer obtained is M
w is 9,200, Mw / Mn is 2.8, ¹³ C-NM
As a result of R measurement, it was found that 85% of the hydrogen atoms of the phenolic hydroxyl group in poly (vinylphenol) had a structure in which t-butoxycarbonyl group was substituted. This polymer is referred to as a polymer (α).

Comparative Synthesis Example 2 12 g of poly (p-vinylphenol) (commercially available from Maruzen Petrochemical Co., Ltd.) and 5.85 g of t-butyl bromoacetate.
And 4.14 g of potassium carbonate were dissolved in 50 g of dioxane, and the mixture was kept at 70 ° C. and then reacted for 6 hours. Next, ethyl acetate was added and the polymerization solution was washed with water several times to remove potassium carbonate, and then the solvent was replaced with acetone. This solution was dropped into a large amount of water to coagulate the polymer, and the coagulated polymer was washed with pure water several times to obtain a white polymer powder (yield 90%).
%) Was obtained. The obtained polymer has Mw of 9,000 and M
w / Mn is 2.5, and as a result of ¹³ C-NMR analysis, it has a structure in which 30% of hydrogen atoms of the phenolic hydroxyl group in poly (vinylphenol) are substituted with t-butoxymethyl group. there were. This polymer is referred to as a polymer (β).

Examples 1 to 8 and Comparative Examples 1 to 4 The components shown in Table 1 (where parts are based on weight) were mixed to prepare a uniform solution, which was then filtered through a membrane filter having a pore size of 0.2 μm. A composition solution was prepared. This composition solution was spin-coated on a silicon wafer and then prebaked under the conditions shown in Table 2 to give a film thickness of 1.0.
A μm resist film was formed. Then, after performing exposure and post-exposure bake under the conditions shown in Table 2, using a 2.38 wt% tetramethylammonium hydroxide aqueous solution, development was performed by a dipping method at 23 ° C. for 1 minute, followed by washing with water to form a resist pattern. Was formed and each resist was evaluated. The evaluation results are shown in Table 3.

[0080]

[Table 1]

Here, the radiation-sensitive acid generator and solvent in each example are as follows. Radiation-sensitive acid generator (B-1): N- (trifluoromethylsulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-
Dicarboximide (ro-2): N- (trifluoromethylsulfonyloxy) -7-oxabicyclo [2.2.1] hept-5-ene-2,3-dicarboximide (ro-3): N -(Camphorsulfonyloxy) naphthylimide (ro-4): triphenylsulfonium triflate (ro-5): biscyclohexyldiazomethane solvent BA: n-butyl acetate EEP: ethyl 3-ethoxypropionate EL: 2-hydroxypropionic acid Ethyl (ethyl lactate) MMP: Methyl 3-methoxypropionate PGMEA: Propylene glycol monomethyl ether acetate

Acid diffusion control agent (C-1): diaminodiphenylmethane (C-2): trihexylamine

[0083]

[Table 2]

[0084]

[Table 3]

The embodiments of the present invention will be summarized and described as follows. 1. (a) A polymer having a repeating unit represented by the above formula (1) [polymer (A)] and (b) a radiation-sensitive acid generator selected from at least one or more imidosulfonate derivatives. A radiation-sensitive resin composition comprising: 2. The polymer (A) is, in addition to the repeating unit represented by the above formula (1), a repeating unit represented by the above formula (2), (3) or (4) or maleic anhydride, maleic acid, The radiation-sensitive resin composition according to the above 1, further containing a repeating unit in which a double bond of a compound having a double bond such as fumaric acid, fumaronitrile, acrylamide, acrylonitrile, vinylpyridine, vinylpyrrolidone, vinylimidazole or vinylaniline is cleaved. . 3. The radiation-sensitive resin composition as described in 1 above, wherein the polymer (A) contains 20% or more of the total number of repeating units represented by the above formula (1). 4. The radiation-sensitive resin composition as described in 1 above, which contains a radiation-sensitive acid generator in an amount of 0.1 to 20 parts by weight per 100 parts by weight of the polymer (A).

[0086]

The radiation-sensitive resin composition of the present invention is free from volume shrinkage, peeling failure from a substrate, and adhesion failure, and is particularly excellent in resolution and pattern shape, and is also excellent in residual film rate, sensitivity and developability. Further, the contrast, heat resistance, etc. are also good, and a highly accurate fine pattern can be stably formed. Moreover, the radiation-sensitive resin composition of the present invention is effectively sensitive to various radiations such as ultraviolet rays, far ultraviolet rays, X-rays and charged particle beams. Therefore, the radiation-sensitive resin composition of the present invention can be very suitably used as a chemically amplified resist for semiconductor device production, which is expected to be further miniaturized in the future.

Claims (1)

[Claims] (A) The following formula (I): (Here, R ¹ represents a substituted methyl group, a substituted ethyl group, a silyl group, a germyl group or an alkoxycarbonyl group, and R 1
² represents -OR ³ or NR ⁴ R ⁵ (provided that R ³ , R ⁴ and R
⁵ are the same or different and each represents a hydrogen atom, a linear alkyl group, a cyclic alkyl group, an aralkyl group, an aryl group, a substituted methyl group, a substituted ethyl group, a silyl group, a germyl group or an alkoxycarbonyl group). A radiation-sensitive resin composition comprising a polymer having a repeating unit represented by and (b) a radiation-sensitive acid generator selected from at least one imidosulfonate derivative.