JPH11352692A - Resist composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a resist composition superior in the resist characteristics and to enable stable superior resolution to be obtained in electro beam allowing by using a polymer obtained by combining an acid-instable group with a copolymer of a hydroxystyrene derivative with an acrylonitile and its derivative. SOLUTION: This resist composition contains the polymer having repeating structural units represented by formula I-III and the radiation-sensitive compound to be allowed to produce an by irradiation with activated radiation. In formulae I-III, each of R<1> -R<3> and R<5> and R<6> is, independently, an H or halogen atom or a 1-4C optionally substituted alkyl or nitro group; R<4> is an acid-instable group or a group having this; and each of x and y and z is a proportion of each structural unit and 0<x<1, 0<y<1, and 0<z<1, and x+y+z=1 and each is an optional number. This polymer has an average molecular weight of 1,000-100,000, preferably, 2,000-50,000 in terms of polystyrene.

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 a semiconductor device using radiation such as far ultraviolet rays such as excimer lasers, charged particles such as X-rays, electron beams and ion beams. The present invention relates to a radiation-sensitive composition suitable as a resist useful for fine processing.

[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. An image is obtained by photolithography technology. By the way, IC, LSI, and V
With the increasing integration, density, and miniaturization of semiconductors in LSI, a technology for forming a fine pattern of 0.5 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. Therefore, the wavelength of 350 to 450 nm
Instead of conventional photolithography using near-ultraviolet light, in order to increase the resolution of exposure, far-ultraviolet light (short-wavelength ultraviolet light) having a short wavelength, krypton fluoride laser light (KrF excimer laser light; wavelength of 248 nm) or electron Lithography technology using lines and the like has been studied. Lithography using conventional near-ultraviolet light
Novolak resin is used as the base polymer,
Although this resin has a good transmittance for ultraviolet light having a wavelength of 350 to 450 nm, it has a shorter wavelength such as far ultraviolet light and K.
Since the transmittance for rF excimer laser light is extremely deteriorated, when novolak resin is used as the base polymer, there are known problems that sufficient sensitivity cannot be obtained and the pattern shape is poor. I have. For the purpose of improving the poor transmittance, a chemically amplified resist using a polyvinyl phenol derivative as a base polymer has been studied (Japanese Patent Publication No. 2-27660), but the pattern shape and resolution still remain. It has not been able to satisfy the demand. Further, as a recent example, a method using a hydrogenated polyvinylphenol derivative as a base polymer for the purpose of further improving the transmittance (Japanese Patent Application Laid-Open No. Hei 5-24967).
No. 3 is known. Although the resolution is improved by this improvement, the required properties of the more advanced resist, especially the resolution and pattern shape,
Further improvements are required. In recent years, drawing techniques using electron beams have attracted attention for fine processing. However, the above-mentioned resist for chemical amplification type far-ultraviolet light exposure is only diverted as a resist for electron beam exposure, and the development of a resist composition suitable for electron beam drawing is currently required.

[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 a copolymer of a hydroxystyrene-based compound and acrylonitrile and a derivative thereof has an acid. The use of a polymer having an unstable group enables a resist composition having excellent resist properties to be obtained.Furthermore, this resist stably has excellent resolution not only for far-ultraviolet light exposure but also for electron beam writing. They have found that it can be realized, and have completed the present invention based on this finding.

[0004]

Thus, according to the present invention, when a polymer having a repeating structural unit represented by the general formulas (1), (2) and (3) is irradiated with activating radiation, A resist composition comprising a radiation-sensitive component that generates an acid (hereinafter, referred to as an acid generator) is provided.

[0005]

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(In the formulas (1) to (3), R ^{1 to} R ³ ,
R ⁵ and R ⁶ are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, a halogen atom or a nitro group, and R ⁴ is an acid labile group or a group containing an acid labile group. x, y and z represent the proportion of each structural unit, and 0
<X <1, 0 <y <1, 0 <z <1, x + y + z = 1. )

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The polymer used in the present invention is a polymer having the repeating structural units represented by the formulas (1), (2) and (3) as essential structural units. This polymer may be a block copolymer or a random copolymer. The lower limit of the weight average molecular weight of this polymer in terms of polystyrene (hereinafter referred to as weight average molecular weight) is usually 1,000.
0, preferably 2,000, with an upper limit of usually 100,
000, preferably 50,000. When the weight-average molecular weight is low, the heat resistance of the resist is reduced or the film is greatly reduced. On the other hand, when the weight-average molecular weight is large, the resolution is lowered, and both are not preferred. The degree of dispersion (Mw / Mn) of the polymer is usually from 1.0 to 3.0, preferably from 1.0 to 2.2. If the degree of dispersion is larger than this range, the resolution is undesirably reduced.

In formulas (1), (2) and (3), R
Specific examples of ^{1 to} R ³ , R ⁵ , and R ⁶ include a hydrogen atom; a methyl group, an ethyl group, an n-propyl group, an isopropyl group,
an alkyl group having 1 to 4 carbon atoms such as an n-butyl group, an s-butyl group, a t-butyl group, or a substitutable alkyl obtained by substituting at least one hydrogen atom of such an alkyl group with a halogen atom, an alkoxy group, or the like; Groups; halogen atoms such as fluorine, chlorine, bromine and iodine; and nitro groups. Among these, a hydrogen atom and a methyl group are particularly preferred from the viewpoint of easiness of polymerization.

R ⁴ in the formula (2) may be any group as long as it functions as an acid labile group which is decomposed by an acid. In particular, -AC (= O) O-R ⁹ (A is a single bond or a divalent organic group, and R ⁹ is an alkyl group having 4 to 10 carbon atoms, a substituted allyl group having 5 to 10 carbon atoms, Number 7-1
2 is a substitutable benzyl group, or a cyclooxaalkyl group, a cyclooxaalkenyl group, a cyclooxoalkyl group or a cyclooxoalkenyl group having 4 to 10 carbon atoms. Group is preferably represented by), especially preferably ^{-CR 7 R 8 C (= O} ) O-R 9 , a group represented by ^{(R 7} and ^{R 8} are the same as ^{R 9)} and -C (= O ) A group represented by OR ⁹ . Further, R ^{7 to} R ⁸ are preferably a hydrogen atom, a methyl group, or an ethyl group, and R ⁹ is preferably a branched having 4 to 6 carbon atoms (particularly, a tertiary branch).
And a substituted allyl group having 5 to 8 carbon atoms, and a benzyl group capable of being substituted with 8 to 10 carbon atoms. The substituted allyl group is a group in which one or more, preferably 2 to 4 alkyl groups having 1 to 3 carbon atoms are bonded instead of the hydrogen atoms of the allyl group. Similarly, the substitutable benzyl group is one in which one, preferably two, alkyl groups having 1 to 3 carbon atoms are bonded in place of the hydrogen atom of the benzyl group.

From the viewpoint of ease of synthesis, t-butyloxycarbonyl, t-amyloxycarbonyl, 1-methyl-1-cyclopropylethyloxycarbonyl, 2-methyl-2-adamantyloxycarbonyl Alkyloxycarbonyl groups such as a group; 1,1-dimethyl-2-propenyloxycarbonyl group, 1-methyl-2-butenyloxycarbonyl group, 3-methyl-2
Alkenyloxycarbonyl groups such as -butenyloxycarbonyl group; 2-tetrahydrofuranyl group, 2-tetrahydropyranyl group, 2- (2,3-dihydrofuranyl) group, 2- (2,3-dihydro-4H- A heteroatom-containing cyclic organic group such as a pyranyl) group; an alkoxyalkyl group such as a 1-ethoxyethyl group; a t-butyloxycarbonylmethyl group, a t-amyloxycarbonylmethyl group, a 1-methyl-1-cyclopropylethyloxycarbonyl Alkyloxycarbonylalkyl groups such as methyl group and 2-methyl-2-adamantyloxycarbonylmethyl group; 1,1-dimethyl-2-propenyloxycarbonylmethyl group, 1-methyl-2-butenyloxycarbonylmethyl group, 3 -Methyl-2-butenyloxycarbonylmethyl group and the like Alkenyloxycarbonyloxyalkyl group; 2-tetrahydrofuranyloxycarbonylmethyl group, 2-tetrahydropyranyloxycarbonylmethyl group, 2- (2,3-dihydrofuranyl) oxycarbonylmethyl group, 2- (2,3-dihydro -4
A hetero atom-containing ring-bonded oxycarbonylmethyl group such as an H-pyranyl) oxycarbonylmethyl group; a 1-ethoxyethyloxycarbonylmethyl group and the like are preferable, and the resist characteristics are also preferable examples.

Specific examples of particularly preferable groups among these include oxycarbonylmethyl groups such as alkyloxycarbonylmethyl group, alkenyloxycarbonylmethyl group, heteroatom-containing ring-bonded oxycarbonylmethyl group, and alkoxyalkyloxycarbonylmethyl group. And especially those having an alkyloxycarbonylmethyl group.

The proportions of the repeating structural units represented by the formulas (1), (2) and (3) are represented by x, y and z, respectively. If the proportion x of the repeating structural unit represented by the formula (1) is small, the resolution is reduced and the pattern shape is deteriorated. Conversely, if the proportion x is too large, the alkali dissolution rate of the resist film is increased and the residual film ratio is reduced. , And the contrast tends to decrease, which is not preferable. When the proportion y of the repeating structural unit represented by the formula (2) is small, the solubility of the unexposed portion of the resist in the developing solution increases, resulting in deterioration of resolution.
Conversely, if the amount is too large, the resolution is reduced and the pattern shape is deteriorated. When the proportion z of the repeating structural unit represented by the formula (3) is large, the sensitivity and the resolution are reduced, and the dry etching resistance is also reduced.

Therefore, when the total of the structural units in the polymer is 1, the lower limit of the proportion x of the unit represented by the formula (1) is usually at least 0.3, preferably at least 0.4, more preferably Is 0.5 or more, the upper limit is usually less than 0.95, preferably 0.85 or less, more preferably 0.8 or less. The lower limit of the proportion y of the unit represented by the formula (2) is usually It is at least 0.05, preferably at least 0.07, more preferably at least 0.1, and the upper limit is usually less than 0.5, preferably at most 0.45, more preferably at most 0.4. The lower limit of the proportion z of the unit represented by the formula (3) is usually at least 0.03, preferably at least 0.05, more preferably at least 0.07, and the upper limit is usually less than 0.5, preferably at least 0.5. Is 0.45 or less, more preferably 0.4 or less.

The polymer containing the repeating structural units represented by the formulas (1), (2) and (3) used as the polymer component in the present invention is obtained by subjecting a monomer giving each structural unit to radical polymerization, Examples of the method include polymerization by a conventional method such as cationic polymerization and anionic polymerization. In addition, it is also possible to polymerize a precursor capable of changing a functional group by a method such as deprotection or substitution without using the monomer itself that provides each of the above-described structural units by these polymerization methods, and to perform post-treatment. it can. For example, when producing a polymer having a structural unit derived from hydroxystyrene, it is possible to copolymerize with another monomer using acetoxystyrene as a precursor instead of hydroxystyrene itself.

Hydroxystyrene represented by the following formula (4)
System monomer and acrylonitrile represented by the following formula (5)
After copolymerization to obtain a copolymer, R⁴Acidic acid represented by
Copolymerization of halides of compounds containing stable groups
One of the formulas (4)
In the above formula (2), the oxygen atom of the hydroxyl group ⁴
A method of introducing a group represented by

[0016]

Embedded image (In the formula (4), R ¹¹ and R ¹² are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, a halogen atom or a nitro group.)

[0017]

Embedded image (In the formula (5), R ¹³ is a hydrogen atom, a C1-C4 substitutable alkyl group, a halogen atom or a nitro group.)

The monomer represented by the formula (4) includes 4-
Hydroxystyrene, 3-hydroxystyrene, 2-hydroxystyrene, α-methyl-4-hydroxystyrene, α-methyl-3-hydroxystyrene, α-methyl-2-hydroxystyrene, 4-hydroxy-3-methylstyrene, -Hydroxy-4-methylstyrene and the like. Among these, 4-hydroxystyrene is particularly preferable from the viewpoint of easy introduction of an acid labile group and good pattern shape.

Examples of the monomer represented by the formula (5) include acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, α-bromoacrylonitrile, α-nitroacrylonitrile and the like.

Specific examples of the polymer used in the present invention include:
4- (substituted allyloxycarbonylmethyloxy) styrene / 4-hydroxystyrene / (meth) acrylonitrile copolymer, 4- (tertiary alkyloxycarbonylmethyloxy) styrene / 4-hydroxystyrene / (meth) acrylonitrile copolymer , 4- (substituted allyloxycarbonyloxy) styrene / 4-hydroxystyrene / (meth) acrylonitrile copolymer, 4- (tertiary alkyloxycarbonyloxy) styrene / 4-hydroxystyrene / (meth) acrylonitrile copolymer Is preferably used.

4- (substituted allyloxycarbonylmethyloxy) styrene / 4-hydroxystyrene / (meth)
Examples of the acrylonitrile copolymer include 4- (3-methyl-2-butenyloxycarbonylmethyloxy) styrene / 4-hydroxystyrene / methacrylonitrile copolymer and 4- (1-methyl-2-butenyloxycarbonyl) Methyloxy) styrene / 4-hydroxystyrene /
Methacrylonitrile copolymer, 4- (1,1-dimethyl-2-propenyloxycarbonylmethyloxy) styrene / 4-hydroxystyrene / methacrylonitrile copolymer, 4- (3-methyl-2-butenyloxy) Carbonylmethyloxy) styrene / 4-hydroxystyrene / acrylonitrile copolymer, 4- (1-methyl-2-
(Butenyloxycarbonylmethyloxy) styrene / 4
-Hydroxystyrene / acrylonitrile copolymer, 4
-(1,1-dimethyl-2-propenyloxycarbonylmethyloxy) styrene / 4-hydroxystyrene /
Acrylonitrile copolymer and the like can be mentioned.

The 4- (tertiary alkyloxycarbonylmethyloxy) styrene / 4-hydroxystyrene / (meth) acrylonitrile copolymer includes t-butyloxycarbonylmethyloxystyrene / 4-hydroxystyrene / methacrylonitrile copolymer. Copolymer, t-butyloxycarbonylmethyloxystyrene / 4-hydroxystyrene / acrylonitrile copolymer, t-amyloxycarbonylmethyloxystyrene / 4-hydroxystyrene / methacrylonitrile copolymer, t-amyloxycarbonylmethyloxystyrene / 4-hydroxystyrene / acrylonitrile copolymer and the like.

The 4- (substituted allyloxycarbonyloxy) styrene / 4-hydroxystyrene / (meth) acrylonitrile copolymer includes 4- (3-methyl-2)
-Butenyloxycarbonyloxy) styrene / 4-hydroxystyrene / methacrylonitrile copolymer, 4-
(1-methyl-2-butenyloxycarbonyloxy)
Styrene / 4-hydroxystyrene / methacrylonitrile copolymer, 4- (1,1-dimethyl-2-propenyloxycarbonyloxy) styrene / 4-hydroxystyrene / methacrylonitrile copolymer, 4- (3-methyl -2-butenyloxycarbonyloxy) styrene /
4-hydroxystyrene / acrylonitrile copolymer,
4- (1-methyl-2-butenyloxycarbonyloxy) styrene / 4-hydroxystyrene / acrylonitrile copolymer, 4- (1,1-dimethyl-2-propenyloxycarbonyloxy) styrene / 4-hydroxystyrene / Acrylonitrile copolymer and the like can be mentioned.

Examples of 4- (tertiary alkyloxycarbonyloxy) styrene / 4-hydroxystyrene / (meth) acrylonitrile copolymer include t-butyloxycarbonyloxystyrene / 4-hydroxystyrene / methacrylonitrile copolymer, t-butyloxycarbonyloxystyrene / 4-hydroxystyrene / acrylonitrile copolymer, t-amyloxycarbonyloxystyrene / 4-hydroxystyrene / methacrylonitrile copolymer, t-amyloxycarbonyloxystyrene / 4-hydroxystyrene / Acrylonitrile copolymer.

The acid generator (PAG) used in the present invention is not particularly limited as long as it generates a Bronsted acid or a Lewis acid when exposed to activating radiation. Organic compounds,
Quinonediazide compound, α, α'-bis (sulfonyl)
Known compounds such as 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.

Examples of onium salts include diazonium salts, ammonium salts, diphenyliodonium triflate, bis (4-t-butylphenyl) iodonium triflate, diphenyliodonium tosylate, bis (4-t-butylphenyl) iodonium tosylate, and diphenyliodonium. 4-nitrobenzenesulfonate, bis (4-t-butylphenyl) iodonium 4-nitrobenzenesulfonate, diphenyliodonium perfluorobutanesulfonate, bis (4
-T-butylphenyl) iodonium perfluorobutanesulfonate, diphenyliodonium amide sulfate, diphenyliodonium N-methylamide sulfate, diphenyliodonium N-cyclohexylamide sulfate, diphenyliodonium N-phenylamide sulfate, bis (4-t -Butylphenyl) iodonium amide sulfate, bis (4-t-butylphenyl) iodonium N-methylamide sulfate, bis (4-t-butylphenyl) iodonium N-cyclohexylamide sulfate, bis (4-t-butyl) Phenyl) iodonium
N-phenylamide sulfate, 4-methoxydiphenyliodonium amide sulfate, 4-methoxydiphenyliodonium N-methylamide sulfate, 4-methoxydiphenyliodonium N-cyclohexylamide sulfate, 4-methoxydiphenyliodonium N-phenylamidosulfate And iodonium salts such as fate.

In addition, triphenylsulfonium triflate, 4-t-butyltriphenylsulfonium triflate, triphenylsulfonium tosylate, 4-t-butyltriphenylsulfonium tosylate, triphenylsulfonium 4-nitrobenzenesulfonate, 4-t- Butyltriphenylsulfonium 4-nitrobenzenesulfonate, triphenylsulfonium perfluorobutanesulfonate, 4-t
-Butyltriphenylsulfonium perfluorobutanesulfonate, triphenylsulfonium amide sulfate, triphenylsulfonium N-methylamide sulfate, triphenylsulfonium N-cyclohexylamide sulfate, triphenylsulfonium N-phenylamide sulfate triphenylsulfonium, 4-t-butyltriphenylsulfonium amide sulfate, 4-t-butyltriphenylsulfonium N-methylamidosulfate, 4-t-
Butyltriphenylsulfonium N-cyclohexylamide sulfate, 4-t-butyltriphenylsulfonium N-phenylamide sulfate triphenylsulfonium, 4-methyltriphenylsulfonium amide sulfate, 4-methyltriphenylsulfonium N-methylamidesulfate Fate, 4-methyltriphenylsulfonium N-cyclohexylamide sulfate, 4-methyltriphenylsulfonium N
-Phenylamide sulfate triphenylsulfonium, 4-methoxytriphenylsulfonium amide sulfate, 4-methoxytriphenylsulfonium
N-methylamide sulfate, 4-methoxytriphenylsulfonium N-cyclohexylamide sulfate, 4-methoxytriphenylsulfonium N-phenylamide sulfate triphenylsulfonium and other sulfonium salts, phosphonium salts, arsonium salts, oxonium salts and the like No.

Examples of the halogenated organic compound include a halogen-containing oxadiazole compound, a halogen-containing triazine compound, a halogen-containing acetophenone compound, a halogen-containing benzophenone compound, a halogen-containing sulfoxide compound, a halogen-containing sulfone compound,
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.

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
And sulfonic acid esters of quinonediazide derivatives such as sulfonic acid esters.

Examples of the α, α-bis (sulfonyl) diazomethane compound include unsubstituted, symmetrically or asymmetrically substituted alkyl, alkenyl, aralkyl and the like.
Α, α′-bis (sulfonyl) diazomethane having an aromatic group or a heterocyclic group is exemplified. 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 an unsubstituted, symmetrically or asymmetrically substituted alkyl group,
A sulfone compound or a disulfone compound having an alkenyl group, an aralkyl group, an aromatic group, or a heterocyclic group can be used.

Examples of the organic acid ester include a sulfonic acid ester and a phosphoric acid ester, and examples of the organic acid amide include a carboxylic acid amide, a sulfonic acid amide, and a phosphoric acid amide. Acid imide, sulfonic imide, phosphoric imide and the like. Among the organic acid esters, sulfonic acid esters are particularly effective. As a preferable specific example of the sulfonic acid ester, a partial sulfonic acid ester compound of a polyhydric phenol, for example, compounds represented by the following formulas (6) to (14) can be used.

[0033]

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[0034]

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[0035]

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As a preferred example of the sulfonic acid ester, a sulfonic acid ester of hydroxyimide, for example, compounds represented by the following formulas (15) to (30) can also be used.

[0037]

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[0038]

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[0039]

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[0040]

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[0041]

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[0042]

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These sulfonic acid esters can be synthesized from commercially available compounds according to a conventional method.

These PAGs may be used alone or as a mixture of two or more. The lower limit is usually 0.01 part by weight, preferably 0.2 part by weight, and the upper limit is usually 50 parts by weight, preferably 30 parts by weight, based on 100 parts by weight of the polymer used in the present invention. Department. 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 containing the polymer and PAG is used after being dissolved in a solvent.
As the solvent, those generally used as a solvent for a resist composition can be used, and specific examples thereof include:
Ketones such as acetone, methyl ethyl ketone, cyclohexanone, cyclopentanone, methyl amyl ketone;
alcohols such as n-propanol, i-propanol, n-butanol, i-butanol, t-butanol and cyclohexanol; ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether and dioxane; ethylene glycol dimethyl ether and ethylene glycol monoethyl Alcohol ethers such as ether, propylene glycol monomethyl ether and propylene glycol monoethyl ether; chain esters such as propyl formate, butyl formate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, methyl butyrate and ethyl butyrate; cyclic esters such as γ-butyrolactone; methyl α-oxypropionate, ethyl α-oxypropionate, methyl 2-methoxypropionate Oxycarboxylic acid esters such as ethyl 2-methoxypropionate; cellosolve esters such as cellosolve acetate, methyl cellosolve acetate, ethyl cellosolve acetate, propyl cellosolve acetate and butyl cellosolve acetate; propylene glycol, propylene glycol monomethyl ether acetate, propylene glycol monoethyl Propylene glycols such as ether acetate and propylene glycol monobutyl ether; diethylene glycols such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether and diethylene glycol diethyl ether; halogenated hydrocarbons such as trichloroethylene; toluene, xylene Examples of any aromatic hydrocarbons include polar solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methylacetamide, N-methylpyrrolidone, etc., and these may be used alone or in combination of two or more. May be used.

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 compounds, and other compatible additives. An agent can be contained.

In the composition of the present invention, the above formulas (1) to (1)
The polymer having the structural unit represented by (3) undergoes the action of an acid generated from an acid generator upon irradiation with radiation, so that the solubility of the irradiated portion changes. The composition of the present invention acts as a positive resist by using an alkaline developer. By providing the repeating structural unit represented by the formula (1) in the polymer, dry etching resistance and
Resist characteristics such as resolution and dissolution inhibiting effect are improved.

The resist composition of the present invention generally uses an aqueous alkali solution as an alkali developing solution. Specific examples thereof include lithium hydroxide, sodium hydroxide, potassium hydroxide, lithium silicate, sodium silicate and potassium silicate. Aqueous solutions of inorganic alkalis such as lithium carbonate, sodium carbonate, potassium carbonate, lithium bicarbonate, sodium bicarbonate, potassium bicarbonate and ammonia; aqueous solutions of primary amines such as ethylamine and propylamine; diethylamine and dipropylamine Aqueous solution of secondary amine; aqueous solution of tertiary amine such as trimethylamine and triethylamine; aqueous solution of alcoholamines such as diethylethanolamine and triethanolamine; tetramethylammonium hydroxide, tetraethylammonium hydroxide De, trimethyl hydroxymethyl ammonium hydroxide, triethyl hydroxymethyl ammonium hydroxide, such as an aqueous solution of quaternary ammonium hydroxide, such as trimethyl hydroxyethyl ammonium hydroxide and the like. The alkali developer may be used alone or in combination of two or more.
Also, if necessary, methanol, ethanol, propanol, water-soluble organic solvents such as ethylene glycol, lithium borate, sodium borate, potassium borate, lithium chloride, sodium chloride,
Inorganic salts such as potassium chloride, lithium bromide, sodium bromide and potassium bromide, surfactants, and dissolution inhibitors for polymers can be added.

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, a glass wafer, or a glass wafer having chromium or chromium oxide deposited on the surface by a conventional method. By removing the resist film, a resist film can be formed. As a coating method at this time, spin coating is particularly awarded. Exposure sources used for exposure for forming a pattern on the thus obtained resist film include far ultraviolet rays, KrF excimer laser light, X-rays, and the like.
Electron beam and the like. Furthermore, a heat treatment (post-exposure bake) is performed after the exposure to terminate the deprotection reaction.

[0050]

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.

Reference Example 1 3-Methyl-2-butenyl
Synthesis of bromoacetate 43.1 g of 3-methyl-2-buten-1-ol (0.
50 mol), 51.6 g (0.51 g) of triethylamine
mol) and dichloromethane (300 ml) were charged into a 1-liter flask and cooled to 0 ° C. While stirring the mixture at 0 ° C, 105.0 g of bromoacetyl bromide (0.
52 mol) was added dropwise over 1 hour, and stirring was further continued at room temperature for 10 hours. The solid content was filtered from the obtained reaction solution,
3 times with saturated aqueous sodium hydrogen carbonate solution and 2 times with saturated saline solution
After washing twice, distillation was performed to obtain 66.5 g of 3-methyl-2-butenyl bromoacetate.

Reference Example 2 Synthesis of 1,1-dimethyl-2-propenyl bromoacetate 43.1 g of 3-methyl-1-buten-3-ol instead of 3-methyl-2-buten-1-ol ( 0.50m
ol), except that 7 was used in the same manner as in Reference Example 1.
5.4 g of 1,1-dimethyl-2-propenyl bromoacetate were obtained.

(Synthesis Example 1) 4- (3-methyl-2-butenyloxycarbonylmethyloxy) styrene / 4-hydroxystyrene / acrylonitrile polymer

Polymerization Step 4-Hydroxystyrene 72.1 g (0.60 mol)
l), 3.7 g (0.07 mol) of acrylonitrile,
Azobisisobutyronitrile 14.8 g (0.09 m
ol) and 150 ml of dioxane were charged into a 500 ml flask and stirred at 80 ° C. for 5 hours under a nitrogen stream.
The obtained reaction solution was poured into 5 liters of xylene, and the resulting precipitate was filtered. After vacuum drying at 50 ° C. for 5 hours, the obtained solid was dissolved in 200 ml of acetone, poured into 3 liters of n-hexane, and the resulting precipitate was filtered (reprecipitation operation). This reprecipitation operation was repeated three times and then dried to obtain 49.3 g of a 4-hydroxystyrene / acrylonitrile polymer. As a result of GPC analysis, the obtained polymer had Mw = 8,600. Also, ¹ H-NM
As a result of R spectrum analysis, the polymerization ratio of 4-hydroxystyrene / acrylonitrile polymer was 92/8.

Modification Step 23.0 g of the 4-hydroxystyrene / acrylonitrile polymer obtained above and 150 ml of acetone were added to 500 m
One flask was charged and dissolved. 13. 3-methyl-2-butenyl bromoacetate obtained in Reference Example 1
5 g (0.07 mol), 10.6 g of anhydrous potassium carbonate
(0.077 mol), 3.3 g of potassium iodide (0.
02 mol), and the mixture was stirred at 50 ° C. for 15 hours.
After removing salts from the obtained reaction solution, the mixture was poured into 5 liters of 0.1% hydrochloric acid, and the resulting precipitate was filtered. 50
After vacuum drying at ℃, the obtained solid was dissolved in 150 ml of THF to remove insoluble components.
The mixture was poured into hydrochloric acid, and the resulting precipitate was filtered (reprecipitation operation). This reprecipitation operation was repeated two more times, followed by drying.
3 g of 4- (3-methyl-2-butenyloxycarbonylmethyloxy) styrene / 4-hydroxystyrene /
An acrylonitrile copolymer was obtained. The resulting polymer is
As a result of GPC analysis, Mw was 9,560. Also,
As a result of ¹ H-NMR spectrum analysis, the ratio of 4- (3-methyl-2-butenyloxycarbonylmethyloxy) styrene / 4-hydroxystyrene / acrylonitrile was 32/60/8.

(Synthesis Example 2) 4- (t-butyloxycarbonylmethyloxy) styrene / 4-hydroxystyrene / acrylonitrile polymer

Modification Step Using 23.0 g of the 4-hydroxystyrene / acrylonitrile polymer obtained in Synthesis Example 1, 13.7 g (0.07 mol) of t-butyl bromoacetate instead of 3-methyl-2-butenyl bromoacetate 29.9 g of 4 by the same modification as in Synthesis Example 1 except that
-(T-butyloxycarbonylmethyloxy) styrene / 4-hydroxystyrene / acrylonitrile copolymer was obtained. As a result of GPC analysis, the obtained polymer was found to have Mw
= 9,100. As a result of ¹ H-NMR spectrum analysis, the ratio of 4- (t-butyloxycarbonylmethyloxy) styrene / 4-hydroxystyrene / acrylonitrile was 31/61/8.

(Synthesis Example 3) 4- (t-butyloxycarbonylmethyloxy) styrene / 4-hydroxystyrene / methacrylonitrile polymer Polymerization step Synthesis example except that 6.7 g (0.10 mol) of methacrylonitrile was used. By the same polymerization operation as in Example 1, 21.9 g of 4
-A hydroxystyrene / methacrylonitrile polymer was obtained. The obtained polymer was analyzed by GPC and found to have Mw = 7,
It was 150. As a result of ¹ H-NMR spectrum analysis, the polymerization ratio of 4-hydroxystyrene / methacrylonitrile polymer was 88/12. Modification Step Except for using 22.8 g of the 4-hydroxystyrene / methacrylonitrile polymer obtained above, 30.5 g of (t-butyloxycarbonylmethyloxy) styrene / 4 was obtained in the same manner as in Synthesis Example 2. -A hydroxystyrene / methacrylonitrile copolymer was obtained. As a result of GPC analysis, Mw of the obtained polymer was 8,220. As a result of ¹ H-NMR spectrum analysis, the ratio of 4- (t-butyloxycarbonylmethyloxy) styrene / 4-hydroxystyrene / methacrylonitrile was 30.
/ 58/12.

Synthesis Example 4 4- (1,1-dimethyl-2)
-Propenyloxycarbonylmethyloxy) styrene / 4-hydroxystyrene / methacrylonitrile polymer Modification step Other than using 14.5 g (0.07 mol) of 1,1-dimethyl-2-propenyl bromoacetate obtained in Reference Example 2. In the same manner as in Synthesis Example 3, 32.8 g of 4- (1,1-dimethyl-2-propenyloxycarbonylmethyloxy) styrene / 4-hydroxystyrene / methacrylonitrile was obtained. The resulting polymer is GP
As a result of C analysis, Mw was 8,400. In ^addition, 1 H
As a result of -NMR spectrum analysis, the ratio of 4- (1,1-dimethyl-2-propenyloxycarbonylmethyloxy) styrene / 4-hydroxystyrene / 2-hydroxyethyl methacrylate was 29/59/12.

(Synthesis Example 5) 4- (t-butyloxycarbonylmethyloxy) styrene / 4-hydroxystyrene / acrylonitrile polymer

Polymerization Step 4-hydroxystyrene 72.1 g (0.60 mol)
l), 18.6 g of acrylonitrile (0.35 mol
l), 14.8 g of azobisisobutyronitrile (0.
09 mol) and 150 ml of dioxane were charged into a 500 ml flask, and stirred at 80 ° C. for 5 hours under a nitrogen stream. The obtained reaction solution was poured into 5 liters of xylene, and the resulting precipitate was filtered. After vacuum drying at 50 ° C. for 5 hours, the obtained solid was dissolved in 200 ml of acetone, poured into 3 liters of n-hexane, and the resulting precipitate was filtered (reprecipitation operation). This reprecipitation operation was repeated three times, then dried, and 52.9 g of 4-hydroxystyrene /
An acrylonitrile polymer was obtained. The resulting polymer is G
As a result of PC analysis, Mw was 9,060. Also, ¹
As a result of H-NMR spectrum analysis, the polymerization ratio of 4-hydroxystyrene / acrylonitrile polymer was 67/33.
Met.

Modification Step 19.6 g of the 4-hydroxystyrene / acrylonitrile polymer obtained above and 150 ml of acetone were added to 500 m
One flask was charged and dissolved. This is t-butyl
9.8 g (0.05 mol) of bromoacetate, 7.6 g (0.055 mol) of anhydrous potassium carbonate, and 3.3 g (0.02 mol) of potassium iodide were added, and the mixture was heated at 50 ° C. for 15 hours.
Stirring was performed for hours. After removing salts from the obtained reaction solution, the mixture was poured into 5 liters of 0.1% hydrochloric acid, and the resulting precipitate was filtered. After vacuum drying at 50 ° C., the obtained solid was
After dissolving in 150 ml of HF and removing insoluble components, 5
The mixture was poured into 1 liter of 0.1% hydrochloric acid, and the resulting precipitate was filtered (reprecipitation operation). After repeating this reprecipitation operation twice, it was dried to obtain 23.3 g of 4- (t-butyloxycarbonylmethyloxy) styrene / 4-hydroxystyrene / acrylonitrile copolymer. The resulting polymer is G
As a result of PC analysis, Mw was 9,920. Also, ¹
As a result of H-NMR spectrum analysis, the ratio of 4- (t-butyloxycarbonylmethyloxy) styrene / 4-hydroxystyrene / acrylonitrile was 23/44 /
33.

Synthesis Example 6 4- (t-butyloxycarbonyloxy) styrene / 4-hydroxystyrene / 1
-Methylcyclohexyl methacrylate polymer Modification step 19.6 g of the 4-hydroxystyrene / acrylonitrile polymer obtained above and 150 ml of acetone were added to 500 m
One flask was charged and dissolved. To this, 10.9 g (0.05 mol) of di-t-butyl dicarbonate and 7.6 g (0.055 mol) of anhydrous potassium carbonate were added, and 5
Stirring was performed at 0 ° C. for 15 hours. After removing salts from the obtained reaction solution, the mixture was poured into 5 liters of 0.1% hydrochloric acid, and the resulting precipitate was filtered. After vacuum drying at 50 ° C., the obtained solid was dissolved in 150 ml of THF to remove insoluble components, and then poured into 5 liters of 0.1% hydrochloric acid, and the resulting precipitate was filtered (reprecipitation operation). After repeating this reprecipitation operation twice, it was dried and 21.3 g of 4- (t-butyloxycarbonyloxy) styrene / 4-hydroxystyrene /
An acrylonitrile copolymer was obtained. The resulting polymer is
As a result of GPC analysis, Mw was 9,730. Also,
As a result of ¹ H-NMR spectrum analysis, the ratio of 4- (t-butyloxycarbonyloxy) styrene / 4-hydroxystyrene / acrylonitrile was 24/43/33.
Met.

(Examples 1 to 6, Comparative Examples 1 and 2) Example 1
The polymers synthesized in Synthesis Examples 1 to 6 above were used as Comparative Examples 1 to 6, and the t-butyl acetate-modified poly (4-vinylphenol) prepared according to the method of Example 1 described in JP-A-5-249673 as Comparative Example 1 ) (Weight-average molecular weight (Mw) by GPC analysis = 6,000), and 100% each of poly (pt-butoxycarbonyloxystyrene) used in Example 2 described in JP-B-2-27660 as Comparative Example 2. Parts, triphenylsulfonium triflate 5 parts as an acid generator and 0.01 part of a fluorine-based surfactant dissolved in 440 parts of ethyl lactate, and a 0.1 μm polytetrafluoroethylene filter (manufactured by Nippon Millipore)
To prepare a resist solution. After spin coating this resist solution on a silicon wafer,
By baking for 90 seconds, a resist film having a thickness of 0.7 μm was formed. This wafer was drawn using an EB drawing apparatus (HL-800D manufactured by Hitachi, Ltd.).
In the drawing pattern, contact holes of a desired size were arranged at a ratio of 2: 1 (length ratio) in an area of 1000 μm × 80 μm. After the drawing, baking was performed at 90 ° C. for 60 seconds, and the resultant was baked with an aqueous tetramethylammonium hydroxide solution.
The immersion phenomenon for a minute was performed to obtain a positive pattern. The results are shown in Table 1. Here, the pattern used for evaluation is a pattern located substantially at the center of the drawing area.

[0065]

[Table 1]

The above evaluation was performed by the following method. “Sensitivity”: 0.20 μm contact hole (C /
H) is defined by the amount of electron beam irradiation resolved. "Resolution": Represents the resolution limit power at the irradiation dose at the above sensitivity

From these results, it was found that a resist composition having ideal sensitivity and high resolution can be obtained by using the polymer of the present invention.

[0068]

As described above, according to the present invention, the resist characteristics such as sensitivity and resolution are excellent, and far ultraviolet rays having a short wavelength and Kr are used.
A resist material suitable for lithography using F excimer laser light or electron beam can be obtained. The resist composition of the present invention is particularly suitable as a positive resist for fine processing of a semiconductor device using an electron beam.

Claims (3)

[Claims] 1. The compounds of the general formulas (1), (2) and (3) Embedded image Embedded image (In the formula (1) to ^(3), an ^{R 1 ~R 3, R 5,} R 6 are each independently a hydrogen atom, an optionally substituted alkyl group having 1 to 4 carbon atoms, a halogen atom or a nitro group, ^{R 4} Is an acid labile group or a group containing an acid labile group, x, y and z represent the proportion of each structural unit, and 0 <x <1, 0 <y
<1, 0 <z <1, x + y + z = 1. A resist composition comprising a polymer having a repeating structural unit represented by formula (1) and a radiation-sensitive component that generates an acid when irradiated with activating radiation. 2. R⁴Is the formula −CR⁷R⁸C (= O) O-
R⁹(Where R⁷, R ⁸Are hydrogen and halogen
, An alkyl group having 1 to 5 carbon atoms, R⁹Has 4 to 10 carbon atoms
Alkyl group, substituted allyl group having 5 to 10 carbon atoms, carbon number
7 to 12 substitutable benzyl groups, or 4 to 10 carbon atoms
Cyclooxaalkyl group, cyclooxaalkenyl group,
Cyclooxoalkyl or cyclooxoalkenyl
2) which is represented by the following formula:
Composition. 3. R ⁴ is of the formula —C (＝ O) O—R ⁹ (wherein R
⁹ is an alkyl group having 4 to 10 carbon atoms, a substituted allyl group having 5 to 10 carbon atoms, a substitutable benzyl group having 7 to 12 carbon atoms, a cyclooxaalkyl group having 4 to 10 carbon atoms, a cyclooxaalkenyl group, The composition according to claim 1, which is represented by an oxoalkyl group or a cyclooxoalkenyl group).