JPH10319596A - Method of forming resist pattern - Google Patents

Abstract

(57) [Summary] (with correction) [PROBLEMS] To form a resist pattern having a desired pattern shape while obtaining high resolution and to reliably form a fine resist pattern even when the PED is long. To provide a method for forming a resist pattern. SOLUTION: (A) A copolymer having a repeating unit represented by the following formula (1) and a repeating unit represented by the following formula (2), and (B) an acid is generated by receiving radiation. Using a radiation-sensitive composition containing a radiation-sensitive acid generator, irradiating a coating film comprising the radiation-sensitive composition with radiation, and thereafter, coating the coating film at a temperature of 130 to 160 ° C. for 30 seconds. There is a step of firing. [In the formula (1), R ¹ represents a hydrogen atom or a methyl group. In the formula (2), R ² represents a hydrogen atom or a methyl group, and R ³ represents a tertiary alkyl group having 4 to 10 carbon atoms. ]

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a method for forming a resist pattern by using a positive-type radiation-sensitive composition to form a patterned resist film.

[0002]

2. Description of the Related Art In recent years, in the field of microfabrication represented by the manufacture of integrated circuit elements, design rules in lithography have been rapidly miniaturized in order to obtain an integrated circuit having a higher degree of integration. Accordingly, development of a lithography process capable of stably performing high-precision fine processing with a line width of, for example, 0.5 μm or less has been actively performed. Conventionally, in the lithography process, visible light (wavelength 700 to 400 nm) and near ultraviolet light (wavelength 400 to 300 nm) have been used. It is difficult to form accurately. Therefore, recently, a wider depth of focus has been obtained, and radiation effective for miniaturization of design rules, for example, K
300 n wavelength such as rF excimer laser light (wavelength 248 nm) and ArF excimer laser light (wavelength 193 nm)
A method using a charged particle beam such as an X-ray such as ultraviolet rays, synchrotron radiation or the like or an electron beam having a wavelength of m or less has been proposed.

As a high-resolution resist responsive to these radiations, "Chemical Amplification Resist" has been proposed by International Business Machines (IBM) Co., Ltd., and improvement of this chemically amplified resist has been actively pursued. ing. The chemically amplified resist contains a radiation-sensitive acid generator, and the radiation-sensitive acid generator is irradiated with radiation to generate a phosphoric acid. Chemical reactions of the components that make up the resist film (eg change in polarity, decomposition of chemical bonds,
A cross-linking reaction or the like is caused, and a resist pattern is formed by utilizing a phenomenon that the solubility of the resist film in a developing solution in a portion irradiated with radiation changes.

In the conventionally proposed chemically amplified resists, the alkali-affinity group in the alkali-soluble resin is t
Radiation-sensitive composition containing a resin component protected by -butyl ester group or t-butoxycarbonyl group (see Japanese Patent Publication No. 27660/1990), and an alkali-affinity group in an alkali-soluble resin is a silyl group. Radiation-sensitive composition containing protected resin component
No. 44290), a radiation-sensitive composition containing a resin component in which an alkali-affinity group in an alkali-soluble resin is protected by a ketal group (JP-A-7-14066).
No. 6) and a radiation-sensitive composition containing a resin component in which an alkali-affinity group in an alkali-soluble resin is protected by an acetal group (see JP-A-2-161436 and JP-A-5-249682). )etc,
Known as relatively good.

However, when a resist pattern is formed using these chemically amplified resists, a sufficiently high resolution cannot be obtained, and for example, it is difficult to form a resist pattern having a line width of 0.25 μm or less. Also,
The resulting resist pattern has a problem that the pattern shape (cross-sectional shape) is, for example, T-shaped.
In particular, when a resist pattern is formed on a BPSG substrate, a SiN substrate, a TiN substrate, or the like, the obtained resist pattern has a shape (fo) in which the lower end has a skirt.
In addition, the problem that the above-mentioned problem may occur is also pointed out. Further, for the reason of the process, the post-irradiation time (Post time) from the irradiation of radiation to the subsequent baking treatment is performed.
Exposure Time Delay and below "PE
D ". In the case where the length of the resist pattern becomes longer, the line width of the obtained resist pattern changes, so that there is a problem that a ranged pattern having the desired dimensions cannot be formed.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made based on the above circumstances, and its object is to provide:
High resolution can be obtained, and a resist pattern having an intended pattern shape can be formed.
It is an object of the present invention to provide a method for forming a resist pattern that can reliably form a fine resist pattern even when the PED is long.

[0007]

Means for Solving the Problems The resist pattern forming method of the present invention comprises (A) a copolymer having a repeating unit represented by the following formula (1) and a repeating unit represented by the following formula (2): And (B) using a radiation-sensitive composition containing a radiation-sensitive acid generator that generates an acid upon receiving radiation, irradiating a coating film composed of the radiation-sensitive composition with radiation, And baking the coating film at a temperature of 130 to 160 ° C. for 30 seconds or more.

[0008]

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[In the formula (1), R ¹ represents a hydrogen atom or a methyl group. In the formula (2), R ² represents a hydrogen atom or a methyl group, and R ³ represents a tertiary alkyl group having 4 to 10 carbon atoms. ]

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for forming a resist pattern according to the present invention will be described in detail. In the method for forming a resist pattern of the present invention, a radiation-sensitive composition containing a component (A) composed of a specific copolymer and a component (B) composed of a radiation-sensitive acid generator is used.

<Component (A)> The copolymer used as the component (A) includes a repeating unit represented by the above formula (1) (hereinafter, referred to as “repeating unit (1)”) and a compound represented by the above formula (1). (Hereinafter referred to as “specific copolymer”) having a repeating unit represented by 2) (hereinafter referred to as “repeating unit (2)”). In the formula (1) representing the repeating unit (1), R ¹ is a hydrogen atom or a methyl group. In the formula (2) representing the repeating unit (2), R ² is a hydrogen atom or a methyl group, and R ³ is a tertiary alkyl group having 4 to 10 carbon atoms. Examples of such an alkyl group include a t-butyl group and a 1,1-dimethylpropyl group. Such a specific copolymer may have one kind of the repeating unit (1) and one kind of the repeating unit (2), or may have two or more kinds of either one or both. .

The content of the repeating unit (2) in the specific copolymer used as the component (A) is preferably 10 to the total of the repeating units (1) and (2).
６０60 mol%, more preferably 15-50 mol%, even more preferably 20-45 mol%. This ratio is 10
When the amount is less than mol%, the resolution of the obtained radiation-sensitive composition tends to decrease, while the ratio is 60%.
When the amount exceeds mol%, the sensitivity of the obtained radiation-sensitive composition tends to decrease.

The specific copolymer includes, for example, the following (a) to (c)
It can be manufactured by any of the methods (d). (A) For example, a (co) polymer having a repeating unit (1) such as poly (p-hydroxystyrene) or poly (p-isopropenylphenol) (hereinafter, referred to as a “phenolic hydroxyl group-containing polymer”) is prepared. A method of reacting a part of the hydroxyl groups in the phenolic hydroxyl group-containing polymer with an unsaturated alkene compound such as isobutene in the presence of an acidic catalyst to effect etherification.

(B) A monomer component containing a phenolic hydroxyl group-containing compound represented by the following formula (3) and a compound represented by the following formula (4) is added to a suitable radical polymerization initiator. And the like, using an appropriate polymerization method such as bulk polymerization, solution polymerization, precipitation polymerization, emulsion polymerization, suspension polymerization, or bulk-suspension polymerization.

[0015]

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[In the formula (3), R ⁴ represents a hydrogen atom or a methyl group. In the formula (4), R ⁵ represents a hydrogen atom or a methyl group, and R ⁶ represents a tertiary alkyl group having 4 to 10 carbon atoms. ]

(C) A monomer component containing the compound represented by the above formula (4) is subjected to bulk polymerization using a radical polymerization initiator, an anion polymerization catalyst, a coordination anion polymerization catalyst, a cation polymerization catalyst or the like. After polymerizing by an appropriate polymerization method such as solution polymerization, precipitation polymerization, emulsion polymerization, suspension polymerization, or bulk-suspension polymerization, some tertiary alkyl groups in the obtained polymer are formed using an acidic catalyst. A method of hydrolysis and / or solvolysis.

(D) A monomer component containing an acetoxystyrene represented by the following formula (5) and a compound represented by the above formula (4) is prepared by using an appropriate radical polymerization initiator or the like. After copolymerization by an appropriate polymerization method such as bulk polymerization, solution polymerization, precipitation polymerization, emulsion polymerization, suspension polymerization, and bulk-suspension polymerization, some acetyl groups in the obtained copolymer are
Hydrolysis and / or solvolysis using a basic catalyst.

[0019]

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[In the formula (5), R ⁷ represents a hydrogen atom or a methyl group. ]

The specific copolymer used as the component (A) has a weight average molecular weight Mw in terms of polystyrene by gel permeation chromatography (hereinafter, referred to as "GPC") of usually 1,000 to 100,000.
0, preferably 3,000 to 40,000, more preferably 3,000 to 30,000. When the weight average molecular weight Mw is less than 1,000, the obtained radiation-sensitive composition tends to have low sensitivity and heat resistance as a resist, while the weight average molecular weight Mw is 100,000. When it exceeds, the obtained radiation-sensitive composition tends to have low solubility in a developing solution.

Further, the specific copolymer contains, if necessary, a repeating unit other than the repeating unit (1) and the repeating unit (2) (hereinafter referred to as "another repeating unit"). Is also good. Examples of a monomer for providing such another repeating unit include, for example, styrene,
Styrenes such as α-methylstyrene; (meth) acrylic acid, maleic acid, fumaric acid, crotonic acid, mesaconic acid,
Unsaturated carboxylic acids such as citraconic acid, itaconic acid, maleic anhydride, and methyl maleic anhydride or their acid anhydrides; methyl ester, ethyl ester, propyl ester, butyl ester, amyl ester of the unsaturated carboxylic acid; -Hydroxyethyl ester, 2,2
Esters such as dimethyl-3-hydroxypropyl ester and benzyl ester; unsaturated nitriles such as (meth) acrylonitrile, maleinitrile, fumaronitrile, mesaconnitrile, citraconitrile, itaconitrile; (meth) acrylamide, crotonamide, Maleamide, fumaramide, mesaconamide,
Unsaturated amides such as citraconamide and itaconamide; unsaturated dicarboxylic acid imides such as maleimide and N-phenylmaleimide; unsaturated alcohols such as vinyl alcohol and (meth) allyl alcohol; vinylaniline, vinylpyridine and N -Vinyl-ε-caprolactam, N-vinylpyrrolidone, N-vinylimidazole,
Other vinyl compounds such as N-vinyl carbazole can be mentioned.

The proportion of other repeating units in the specific copolymer used as the component (A) is as follows:
And 5 for the total of 100 parts by weight of the repeating unit (2)
It is preferably 0 parts by weight or less. When this proportion exceeds 50 parts by weight, developability and / or resolution tend to deteriorate.

<Component (B)> The radiation-sensitive acid generator used as the component (B) is a compound that generates an acid upon receiving radiation. As such a radiation-sensitive acid generator, an onium salt, a sulfone compound, a sulfonate compound, a sulfonemide compound, a diazomethane compound and the like can be used.

Onium salts; Examples of onium salts include iodonium salts, sulfonium salts, phosphonium salts,
A diazonium salt, an ammonium salt, a pyridinium salt and the like can be used, and specific examples thereof include bis (t-butylphenyl) iodonium nonaflate, bis (t-
Butylphenyl) iodonium triflate, bis (t
-Butylphenyl) iodonium pyrene sulfonate,
Bis (t-butylphenyl) iodonium dodecylbenzenesulfonate, bis (t-butylphenyl) iodonium p-toluenesulfonate, bis (t-butylphenyl) iodoniumbenzenesulfonate, bis (t
-Butylphenyl) iodonium 10-camphorsulfonate, bis (t-butylphenyl) iodonium octanesulfonate, diphenyliodonium p-toluenesulfonate, diphenyliodonium benzenesulfonate, diphenyliodonium 10-camphorsulfonate, diphenyliodonium octanesulfonate, diphenyliodonium nonaflate, Diphenyliodonium triflate, diphenyliodonium pyrene sulfonate, diphenyliodonium dodecylbenzenesulfonate, triphenylsulfonium nonaflate, triphenylsulfonium triflate,
Examples include triphenylsulfonium hexafluoroantimonate, triphenylsulfonium naphthalene sulfonate, t-butoxyphenyldiphenyltriphenylsulfonium nonaflate (hydroxyphenyl) benzylmethylsulfonium toluenesulfonate, and the like.

Sulfone compound; Examples of the sulfone compound include β-ketosulfone, β-sulfonylsulfone, and α-diazo compounds thereof.
Specific examples thereof include phenacylphenylsulfone, mesitylphenacylsulfone, bis (phenylsulfonyl) methane, 4-trisphenacylsulfone, and the like.

Sulfonate compound: As the sulfonic acid ester compound, for example, alkyl sulfonic acid ester, haloalkyl sulfonic acid ester, aryl sulfonic acid ester, imino sulfonate and the like can be used. Specific examples thereof include benzoin tosylate,
Pyrogallol tristriflate, pyrogallol methanesulfonic acid triester, nitrobenzyl-9,10-
Examples include diethoxyanthracene-2-sulfonate, α-methylol benzoin tosylate, α-methylol benzoin octane sulfonic acid ester, α-methylol benzoin trifluoromethane sulfonic acid ester, and α-methylol benzoindodecyl sulphonate.

Sulfonimide compound: As the sulfonimide compound, a compound represented by the following formula (6) can be used.

[0029]

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[In the formula (6), X is an alkylene group,
Represents a divalent group such as an arylene group or an alkoxylene group,
R ⁸ represents a monovalent group such as an alkyl group, an aryl group, a halogen-substituted alkyl group, and a halogen-substituted aryl group. ]

Specific examples of such a sulfonimide compound include N- (trifluoromethylsulfonyloxy) succinimide, N- (trifluoromethylsulfonyloxy) phthalimide, N- (trifluoromethylsulfonyloxy) diphenylmaleimide and N- (trifluoromethylsulfonyloxy) diphenylmaleimide. -(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- (camphor-sulfonyloxy) naphthyldicarboximide, 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, N- (2-trifluoromethylphenylsulfonyloxy) naphthylimide, N- (4-fluorophenylsulfonyloxy) succinimide, N- (2-fluorophenyl) phthalimide, N- (4-fluorophenylsulfonyloxy) diphenylmaleimide, N- (4-fluorophenylsulfonyloxy) bicyclo [2.1.1] hept-5-ene-2,3-dicarboximide, N- (trifluoromethylsulfonyl) Oxy) -7-oxabicyclo [2.1.1] hept-5-ene-2,3-dicarboximide, N- (4-fluorophenylsulfonyloxy) bicyclo [2.1.1] heptane-5 6-oxy-2,3-dicarboximide, N- (4-fluorophenylsulfonyl) Carboxy) naphthyl dicarboxyimide and the like.

Diazomethane compound: As the diazomethane compound, for example, a compound represented by the following formula (7) can be used.

[0034]

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[In the formula (7), R ⁹ and R ¹⁰ are
Each represents a monovalent group such as an alkyl group, an aryl group, a halogen-substituted alkyl group, and a halogen-substituted aryl group, which may be the same or different. ]

Specific examples of such a diazomethane compound include bis (trifluoromethylsulfonyl) diazomethane, bis (cyclohexylsulfonyl) diazomethane, bis (phenylsulfonyl) diazomethane, bis (p-toluenesulfonyl) diazomethane, methylsulfonyl-p -Toluenesulfonyldiazomethane, 1-cyclohexylsulfonyl-1- (1,1-dimethylethylsulfonyl) diazomethane, bis (1,1-dimethylethylsulfonyl) diazomethane and the like.

In the present invention, it is preferable to use a radiation-sensitive acid generator which generates an acid having a boiling point of 165 ° C. or more under normal pressure. Boiling point under normal pressure is 165 ℃
When a radiation-sensitive acid generator that generates less acid is used, the shape of the resist pattern obtained after development tends to deteriorate. Examples of the radiation-sensitive acid generator that generates an acid having a boiling point of 165 ° C. or more under normal pressure include, among the above-described radiation-sensitive acid generators, bis (t-butylphenyl) iodonium perfluorobutanesulfonate, bis ( t-butylphenyl) iodonium dodecylbenzenesulfonate, bis (t-butylphenyl) iodonium toluenesulfonate, bis (t-butylphenyl) iodonium 10-camphorsulfonate, bis (t-butylphenyl) iodonium octanesulfonate, diphenyliodonium toluenesulfonate,
Diphenyliodonium 10-camphorsulfonate, diphenyliodonium octanesulfonate, diphenyliodonium perfluorobutanesulfonate, diphenyliodonium dodecylbenzenesulfonate, triphenylsulfonium perfluorobutanesulfonate, triphenylsulfonium 10camphorsulfonate, triphenylsulfonium naphthalene sulfonate, t-butoxyphenyl Diphenyltriphenylsulfonium nonaflate, (hydroxyphenyl) benzylmethylsulfonium toluenesulfonate, N- (camphorsulfonyloxy) succinimide, N- (camphorsulfonyloxy) phthalimide, N- (camphorsulfonyloxy) diphenylmaleimide, N- (camphor) Ruhoniruokishi) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (camphorsulfonyloxy oxy) -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- (nonafluoronylmethylsulfonyloxy) succinimide,
N- (nonafluoronylmethylsulfonyloxy) phthalimide, N- (nonafluoronylmethylsulfonyloxy) diphenylmaleimide, N- (nonafluoronylmethylsulfonyloxy) bicyclo [2.2.1] hept-5-en-2 , 3-dicarboximide, N- (nonafluoronylmethylsulfonyloxy) -7-oxabicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (nonafluoronylsulfonyl) Oxy) naphthylimide, N- (nonafluoronylmethylsulfonyloxy) bicyclo [2.2.1] heptane-5,6-oxy-2,3-dicarboximide are preferred. These radiation-sensitive acid generators are used alone or in combination of two or more.

In the present invention, the ratio of the radiation-sensitive acid generator used as the component (B) is 0.5 to 20 with respect to 100 parts by weight of the copolymer used as the component (A).
Parts by weight, particularly preferably 1 to 10 parts by weight. If this proportion is less than 0.5 part by weight, the sensitivity of the resulting radiation-sensitive composition tends to decrease. On the other hand, when this ratio exceeds 20 parts by weight, when the composition is stored in the state of a radiation-sensitive composition solution described later, the tendency of foreign matter to be generated during the storage increases.

<Component (C)> The radiation-sensitive composition used in the present invention may contain an acid diffusion controller as the component (C) in addition to the components (A) and (B). preferable. This acid diffusion controlling agent has a function of controlling a phenomenon in which an acid generated from a radiation-sensitive acid generator is diffused in a coating film by irradiation of radiation, and suppressing a chemical reaction in a non-radiation-irradiated light region of the coating film. Things. By containing such an acid diffusion controller,
The storage stability and resolution of the radiation-sensitive composition can be improved, and even if the PED is long, a change in the line width of the obtained resist pattern can be reliably suppressed.

As the acid diffusion controller, a nitrogen-containing organic compound whose basicity is not changed by irradiation or baking is preferably used. Examples of the nitrogen-containing organic compound include, for example, an amine compound represented by the following formula (8) (hereinafter, referred to as “nitrogen-containing compound (I)”) and two nitrogen atoms in the same molecule.
Diamino compounds (hereinafter referred to as “nitrogen-containing compounds (I
I) ". ), A diamino polymer having three or more nitrogen atoms (hereinafter referred to as “nitrogen-containing compound (III)”),
Amide group-containing compounds, urea compounds, nitrogen-containing heterocyclic compounds and the like can be used.

[0041]

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[In the formula (8), R ¹¹ represents an alkyl group, an aryl group or an aralkyl group, and R ¹² and R ¹³ each independently represent a hydrogen atom, an alkyl group, an aryl group or an aralkyl group. ]

Specific examples of the nitrogen-containing compound (I) include, for example, n-hexylamine, n-heptylamine,
monoalkylamines such as n-octylamine, n-nonylamine and n-decylamine; di-n-butylamine, di-n-pentylamine, di-n-hexylamine, di-n-heptylamine, di-n- Dialkylamines such as octylamine, di-n-nonylamine and di-n-decylamine; triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine, tri-n-hexylamine -N-
Heptylamine, tri-n-octylamine, tri-n
Trialkylamines such as -nonylamine and tri-n-decylamine; aniline, N-methylaniline, N, N
-Dimethylaniline, 2-methylaniline, 3-methylaniline, 4-methylaniline, 4-nitroaniline,
Examples thereof include aromatic amines such as diphenylamine, triphenylamine, and naphthylamine.

Specific examples of the nitrogen-containing compound (II) include, for example, ethylenediamine, N, N, N ', N'-tetramethylethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4'-diaminodiphenylmethane, , 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 and the like can be mentioned. Specific examples of the nitrogen-containing compound (III) include, for example, polyethyleneimine, polyallylamine, and dimethylaminoethylacrylamide polymers.

Specific examples of the amide group-containing compound include, for example, formamide, N-methylformamide,
N, N-dimethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, propionamide, penzamide, pyrrolidone, N-methylpyrrolidone and the like can be mentioned. Specific examples of the urea compound include, for example, urea, methylurea,
1-dimethylurea, 1,3-dimethylurea, 1,
Examples thereof include 1,3,3-tetramethylurea, 1,3-diphenylurea, and tributylthiourea. Specific examples of the nitrogen-containing heterocyclic compound include imidazoles such as imidazole, benzimidazole, 4-methylimidazole, and 4-methyl-2-phenylimidazole; pyridine, 2-methylpyridine, 4-methylpyridine, Ethylpyridine, 4-ethylpyridine, 2-phenylpyridine, 4-phenylpyridine, N
Pyridines such as -methyl-4-phenylpyridine, nicotine, nicotinic acid, nicotinamide, quinoline, 8-oxyquinoline, and acridine; pyrazine, pyrazole, pyridazine, quinosaline, purine, pyrrolidine, piperidine, morpholine, Methyl morpholine,
Piperazine, 1,4-dimethylpiperazine, 1,4-diazabicyclo [2.2.2] octane and the like can be mentioned.

Among these nitrogen-containing organic compounds, a nitrogen-containing compound (I), a nitrogen-containing heterocyclic compound and the like are preferable in that the obtained pattern has good shape and good resolution. Further, among the nitrogen-containing compounds (I), trialkylamines are particularly preferable, and among the nitrogen-containing heterocyclic compounds, pyridines are particularly preferable. These nitrogen-containing organic compounds are:
They can be used alone or in combination of two or more.

The proportion of the acid diffusion controller used as the component (C) is based on the copolymer 100 used as the component (A).
Usually 15 parts by weight or less, preferably 0.1 part by weight, based on parts by weight.
001 to 15 parts by weight, more preferably 0.001 to 10 parts by weight
Parts by weight, more preferably 0.005 to 5 parts by weight. If this proportion exceeds 15 parts by weight, the sensitivity of the resulting radiation-sensitive composition and the developability of the exposed area tend to decrease. If the amount of the acid diffusion controller is less than 0.001 part by weight, the pattern shape and dimensions may change depending on the conditions of each step in forming the resist pattern.

<Other Components> (1) Surfactant: The radiation-sensitive composition used in the present invention may contain a surfactant. Specific examples of such a surfactant include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene octyl phenol ether, polyoxyethylene nonyl phenol ether, polyethylene glycol dilaurate, and polyethylene glycol distearate. Examples of commercially available products include F-Top EF301, EF303, and EF352 (manufactured by Tochem Products), and Megafax F171 and F173.
(Dai Nippon Ink Co., Ltd.), Florado FC430, F
C431 (manufactured by Sumitomo 3M Limited), Asahi Guard A
G710, Surflon S-382, SC101, SC1
02, SC103, SC104, SC105, SC10
6 (manufactured by Asahi Glass Co., Ltd.), organosiloxane polymer K
P341 (manufactured by Shin-Etsu Chemical Co., Ltd.), polyflow No. 1 which is an acrylic or methacrylic acid (co) polymer.
75, no. 95 (trade name, Kyoeisha Yushi Kagaku Kogyo Co., Ltd.)
Manufactured). The proportion of the surfactant used is (A)
2 parts per 100 parts by weight of the copolymer used as a component
It is preferable that the amount is not more than part by weight.

(2) Sensitizer: The radiation-sensitive composition used in the present invention may contain a sensitizer. The sensitizer absorbs radiation energy and transmits the energy to the radiation-sensitive acid generator, thereby increasing the amount of acid generated. , The apparent sensitivity of the resulting resist can be improved. Specific examples of preferred sensitizers include benzophenones, rose bengals, and anthracenes. The use ratio of these sensitizers is preferably 50 parts by weight or less based on 100 parts by weight of the copolymer used as the component (A).

(3) High-molecular component and low-molecular component: The radiation-sensitive composition used in the present invention may contain, if necessary,
A high molecular component or a low molecular component other than the component (A) can be contained. Such a high molecular component or a low molecular component has good compatibility with the copolymer (A) used as the component (A) without impairing the uniformity of a coating film obtained when applied to a substrate. It is preferable to use one. Specific examples of such high molecular components include p-hydroxystyrene-styrene copolymer, and specific examples of low molecular components include bisphenol A, 2,2
-Bis (t-butoxyphenyl) propane and the like. The proportion of the high molecular weight component and low molecular weight component other than the component (A) is such that the total of the repeating unit (1) and the repeating unit (2) in the copolymer used as the component (A) is 1
It is preferably 50 parts by weight or less based on 00 parts by weight.

(4) Other Additives The radiation-sensitive composition used in the present invention may contain a dye and / or a pigment. The effect of halation during irradiation can be reduced. In addition, the radiation-sensitive composition used in the present invention can contain an adhesion aid, whereby the adhesion between the obtained resist film and the substrate can be improved. Further, the radiation-sensitive composition used in the present invention may contain additives such as an antihalation agent such as 4-hydroxy-4′-methylchalcone, a shape improver, a storage stabilizer and an antifoaming agent. it can.

<Organic solvent> The above radiation-sensitive composition is
Usually, it is used in the state of a radiation-sensitive composition solution (hereinafter, referred to as “composition solution”) dissolved or dispersed in an organic solvent. Specifically, the radiation-sensitive composition is uniformly dissolved or dispersed in an organic solvent so that the concentration of the total solid content is, for example, 5 to 50% by weight, preferably 10 to 40% by weight. A composition solution is prepared by filtering with a filter having a pore size of about 0.2 μm.

Examples of the organic solvent used for preparing the composition solution include ethylene glycol monoalkyl ether acetates such as ethylene glycol monomethyl ether acetate and ethylene glycol monoethyl ether acetate; propylene glycol monomethyl ether and propylene glycol monoethyl. Propylene glycol monoalkyl ethers such as ether, propylene glycol monopropyl ether and propylene glycol monobutyl ether; propylene glycol dialkyl ethers such as propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol dipropyl ether and propylene glycol dibutyl ether; propylene glycol Monomethyl ether ace Acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, and other propylene glycol monoalkyl ether acetates; lactate esters such as methyl lactate, ethyl lactate, n-propyl lactate, and isopropyl lactate N-amyl formate, isoamyl formate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-acetate
Aliphatic carboxylic acid esters such as butyl, isobutyl acetate, n-amyl acetate, isoamyl acetate, isopropyl propionate, n-butyl propionate and isobutyl propionate; ethyl hydroxyacetate, 2-hydroxy-2
-Ethyl methylpropionate, methyl 2-hydroxy-3-methylacetate, ethyl methoxyacetate, ethyl ethoxyacetate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, 3-ethoxypropionic acid Ethyl, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-methyl-3-methoxybutyl propionate, 3-methyl-3-methoxybutyl butyrate, methyl acetoacetate, ethyl acetoacetate, pyrpine Methyl acid,
Other esters such as ethyl pyruvate; aromatic hydrocarbons such as toluene and xylene; ketones such as methyl ethyl ketone, methyl propyl ketone, methyl butyl ketone, 2-heptanone, 3-heptanone, 4-heptanone, cyclohexanone; -Methylformamide, N, N-dimethylformamide, N-methylacetamide, N, N
Amides such as -dimethylacetamide and N-methylpyrrolidone; and laclones such as γ-butyrolactone.

<Formation of Resist Pattern> In the present invention, a resist pattern is formed by using the above radiation-sensitive composition, for example, as follows. First, the composition solution prepared as described above is applied to the surface of a substrate on which a resist pattern is to be formed, for example, a substrate such as a silicon wafer or a wafer coated with aluminum, and then subjected to a heat treatment (hereinafter, referred to as “prebaked”). To form a coating film composed of the radiation-sensitive composition.
Then, the coating film is subjected to a radiation irradiation process (hereinafter, referred to as “exposure process”) through a predetermined mask.

In the above, as a means for applying the composition solution to the surface of the substrate, a spin coating method, a casting coating method, a roll coating method, or the like can be used. The pre-bake conditions are a heating temperature of, for example, 70 ° C. to 160 ° C. and a heating time of, for example, 30 to 300 seconds. The radiation used for the exposure treatment is appropriately selected depending on the type of the radiation-sensitive acid generator contained in the radiation-sensitive composition, and is, for example, ultraviolet light such as i-ray (wavelength 365 nm); ArF excimer laser (wavelength 193 nm), far ultraviolet rays such as KrF excimer laser (wavelength 248 nm), X-rays such as synchrotron radiation, and charged particle beams such as electron beams. The irradiation energy amount is appropriately selected according to the type of each component in the radiation-sensitive composition used, the composition, and the like.

Next, a baking treatment (hereinafter referred to as “post-exposure bake”) is performed on the exposed coating film. In the present invention, the post-exposure bake is performed at a heating temperature of 130 to 1.
60 ° C., heating time is 30 seconds or more, preferably 30 to 1
This is performed under the condition of 80 seconds. By performing post-exposure baking under such conditions, high resolution can be obtained, and even if the PED is long, the size and shape of the pattern do not change, and a fine resist pattern can be reliably formed. it can. When the heating temperature in the post-exposure bake is lower than 130 ° C., if the PED lengthens, the dimensions and shape of the pattern may change, particularly when forming a resist pattern on the surface of a SiN substrate or a BPSG substrate. However, depending on conditions such as the resist film thickness, remarkable footing occurs in the obtained resist film, so that it cannot be applied to the manufacture of an actual device. On the other hand, when the heating temperature in the post-exposure bake exceeds 160 ° C., the rectangularity of the obtained resist pattern is impaired, and a popcorn-shaped development residue may be generated near the substrate. Further, if the heating time in the post-exposure bake is less than 30 seconds, sufficient resolution performance cannot be obtained.

Then, the exposed film is subjected to a development treatment with an alkali developing solution to remove the radiation-irradiated portion of the coating film.
A patterned resist film is formed. The developing process is usually performed by a method such as a shower developing method, a spray developing method, a dip developing method, and a paddle (liquid) developing method.
The treatment is performed under the conditions of a treatment temperature of 10 to 50 ° C. and a treatment time of 30 to 200 seconds. Examples of the alkali developing solution for performing the developing treatment include alkali metal hydroxides; aqueous ammonia; mono-, di- or tri-alkylamines; mono-, di- or tri-alkanolamines; And tetraalkylammonium hydroxides; choline; 1,8-diazabicyclo- [5,4,
0] -7-undecene, 1,5-diazabicyclo-
An alkaline compound such as [4,3,0] -5-nonene,
Usually, an alkaline aqueous solution dissolved to a concentration of 1 to 10% by weight, preferably 1 to 5% by weight can be used. A water-soluble organic solvent such as methanol or ethanol or a surfactant can be appropriately added to the developer composed of the alkaline aqueous solution. When a developer composed of such an alkaline aqueous solution is used, it is generally preferable to wash the resist film with water after development. In the formation of the resist pattern, a protective film can be provided on the resist film in order to prevent the influence of a basic impurity or the like contained in an environmental atmosphere.

Hereinafter, preferred embodiments of the resist pattern forming method of the present invention will be listed. (1) A method for forming a resist pattern, wherein the radiation-sensitive acid generator in the radiation-sensitive composition generates an acid having a boiling point of 165 ° C. or higher under normal pressure. (2) A method for forming a resist pattern using a radiation-sensitive composition containing an acid diffusion controller. (3) The acid diffusion controller contained in the radiation-sensitive composition,
A method for forming a resist pattern, which is an amine compound or a nitrogen-containing heterocyclic compound represented by the above formula (8).

[0059]

EXAMPLES Hereinafter, specific examples of the method for forming a resist pattern according to the present invention will be described, but the present invention is not limited to these examples. In the following examples, the weight average molecular weight Mw and the number average molecular weight Mn of the copolymer were measured using a GPC column (G200 manufactured by Tosoh Corporation).
0HXL 2 pcs, G3000HXL 1 pcs, G4000
HXL 1), the elution solvent tetrahydrofuran, flow rate 1.0 ml / min, column temperature 40 ° C.
Under the analysis conditions described above, measured by gel permeation chromatography using monodisperse polystyrene as a standard.

<Synthesis Example 1> pt-butoxystyrene 3
00 g (1.7 mol) and 2.0 g of azobisisobutyronitrile were dissolved in 300 g of dioxane, and this solution was heated at 60 ° C. for 16 hours under a nitrogen atmosphere to obtain p-t- Butoxystyrene was polymerized. The resulting poly-pt-butoxystyrene resin was coagulated by dropping the obtained reaction solution into a large amount of methanol. The coagulated resin was redissolved in dioxane, diluted sulfuric acid was added to the solution, and the solution was heated at 60 ° C. for 1 hour to perform a hydrolysis reaction. Transfer this resin solution to a separatory funnel, add a large amount of ethyl acetate and water, shake well, and allow to stand to separate into an ethyl acetate layer (upper layer) and an aqueous layer (lower layer). And the aqueous layer was discarded. Then, this operation was repeated until the discarded aqueous layer became completely neutral, and then the resin solution was dried under reduced pressure, and the obtained resin was redissolved in acetone. The resin solution was dropped into a large amount of water to coagulate the resin, and the resulting white powdery resin was filtered and then dried by heating at 50 ° C. under reduced pressure overnight. This resin has a weight average molecular weight Mw (hereinafter, referred to as "Mw") of 18,000, and a ratio Mw / Mn (hereinafter, referred to as a weight average molecular weight Mw to a number average molecular weight Mn).
It is called “Mw / Mn”. ) Is 1.75, and ¹³ C—N
As a result of analysis by MR, p-hydroxystyrene and p-hydroxystyrene
Copolymer with -t-butoxystyrene (p-hydroxystyrene: pt-butoxystyrene in a molar ratio of 65:
35). This resin is referred to as a specific copolymer (A1).

<Synthesis Example 2> 50 g of pt-butoxy-α-methylstyrene monomer purified by distillation was mixed with 500 g of
g-tetrahydrofuran solvent and cooled to -78 ° C while n-butyllithium (0.0005 mol)
Anionic polymerization was carried out for 2 hours in the presence of a catalyst, and a small amount of methanol was added thereto to terminate the polymerization reaction. The resulting pt-butoxy-α-methylstyrene resin was solidified by dropping the obtained reaction solution into a large amount of methanol. After the coagulated white resin was redissolved in dioxane, dilute sulfuric acid was added to the solution, and a hydrolysis reaction was performed at 60 ° C. for 1 hour. This resin solution is transferred to a separating funnel, and a large amount of ethyl acetate and water are added thereto, shaken well, and allowed to stand, so that the ethyl acetate layer (upper layer) is left.
And an aqueous layer (lower layer), and the aqueous layer was discarded. Then, this operation was repeated until the discarded aqueous layer became completely neutral, and then the resin solution was dried under reduced pressure, and the obtained resin was redissolved in acetone. The resin solution was dropped into a large amount of water to coagulate the resin, and the resulting white powdery resin was filtered and then dried by heating at 50 ° C. under reduced pressure overnight. This resin has Mw of 14,000, Mw / Mn of 1.05, and ¹³ C—N
As a result of analysis by MR, a copolymer of p-hydroxy-α-methylstyrene and pt-butoxy-α-methylstyrene (p-hydroxy-α-methylstyrene: p-hydroxystyrene)
t-butoxy-α-methylstyrene in a molar ratio of 69: 3
1). This resin is referred to as a specific copolymer (A2).

<Synthesis Example 3> m-hydroxystyrene 78
g, 44 g of mt-butoxystyrene and 14 g of N-vinylpyrrolidone were dissolved in 300 ml of dioxane, followed by bubbling with nitrogen gas for 30 minutes. 6.5 g of azopisisobutyronitrile was added to this solution, and heated at 60 ° C. for 16 hours under a nitrogen atmosphere to obtain m-hydroxystyrene, mt
-Copolymerization of butoxystyrene and N-vinylpyrrolidone. The resulting reaction solution was dropped into a large amount of water to coagulate the formed copolymer resin, filtered, and dried by heating under reduced pressure at 50 ° C. overnight. This resin has Mw of 9,000,
Mw / Mn was 1.8, and as a result of analysis by ¹³ C-NMR, a copolymer of m-hydroxystyrene, mt-butoxystyrene, and N-vinylpyrrolidone (m-hydroxystyrene: mt- Butoxystyrene: N-vinylpyrrolidone was in a molar ratio of 65:25:10).
This resin is referred to as a specific copolymer (A3).

<Examples 1 to 15 and Comparative Examples 1 to 3> (1) Preparation of radiation-sensitive composition solution: After mixing the components according to the formulation shown in Tables 1 and 2, the solution was mixed. A composition solution containing the radiation-sensitive composition was prepared by filtration through a membrane filter having a pore size of 0.2 μm. In Tables 1 and 2, bis (t-butylphenyl) iodonium nonaflate (acid generated: perfluorobutanesulfonic acid) and radiation-sensitive acid generator (B2) were used as the radiation-sensitive acid generator (B1).
Bis (t-butylphenyl) iodonium p-toluenesulfonate (acid generated: p-toluenesulfonic acid), and diphenyliodonium-10-camphorsulfonate (acid generated: 10-camphor) as a radiation-sensitive acid generator (B3) Sulfonic acid), triphenylsulfonium perfluorobutanesulfonate (acid generated: perfluorobutanesulfonic acid) as the radiation-sensitive acid generator (B4), and t-butoxyphenyldiphenylsulfonium- as the radiation-sensitive acid generator (B5). 10-
Camphorsulfonate (generated acid: 10-camphorsulfonic acid), N as radiation-sensitive acid generator (B5)
-(10-Camphorsulfonyloxy) bicyclo [2.2.1] heptane-5,6-oxy-2,3-dicarboximide (acid generated: 10-camphorsulfonic acid) was used. In the above, perfluorobutanesulfonic acid, p-toluenesulfonic acid and 10-camphorsulfonic acid have a boiling point of 165 ° C. or higher, or melt or decompose at a temperature higher than 165 ° C. The p-hydroxystyrene-styrene copolymer has a weight average molecular weight Mw of 3,000,
The copolymerization ratio of hydroxystyrene and styrene is 9: 1.

[0064]

[Table 1]

[0065]

[Table 2]

(2) Formation of resist pattern: The above-mentioned radiation-sensitive composition solution is applied to the surface of a substrate on which a resist film is to be formed (hereinafter, referred to as a “substrate for forming a resist film”) by spin coating. After that, pre-baking was performed to form a coating film having a thickness of 0.7 μm. Then, an optimal exposure amount (design line width 0.26 μm)
m, a line and space pattern (1L1S) having a line width of 1 to 1) is exposed, and immediately after the exposure, baking is performed. Using a 38% by weight aqueous solution of tetramethylammonium hydroxide by paddle development
After performing a development process at a temperature of 1 ° C. for 1 minute, the resultant was washed with pure water and dried to form a resist pattern.
In the above, as shown in Table 3 below, as the material of the resist film forming substrate and the radiation for the exposure treatment,
The pre-bake and post-exposure bake were performed under the conditions shown in Table 3 below. In Table 3, the organic lower antireflection film was manufactured by Brewer and used as a KrF excimer laser (wavelength: 248 nm).
"Stepper NSR-2005EX8" manufactured by Nikon Corporation
A "and an accelerating voltage of 50K as an electron beam generator.
An electron beam drawing apparatus for direct drawing of eV was used.

[0067]

[Table 3]

(3) Evaluation: The following items were evaluated for the above-described resist pattern forming method. Table 4 shows the results.

[Resolution] The minimum size (μm) of the resist pattern resolved by the above method was measured and defined as the resolution.

[Pattern Shape] For a line and space pattern having a design line width of 0.26 μm formed by the above method, the line width at the upper end of the pattern is La, the line width at the center of the pattern is Lb, and the pattern lower end is Lb. The line width of the part is L
It was set as c and evaluated according to the following criteria. Good: 0.9 × Lb <La <1.1 × Lb, and 1.
0 × Lb <Lc <1.3 × Lb, defective (T-type defective): La ≧ 1.1 × Lb, defective (round-top defective): La ≦ 0.9 × Lb, defective ( Poor hem pulling: Lc ≧ 1.3 × Lb, defective (undercut defect): Lc ≦ 1.3 × Lb

[Ped Stability] In the formation of the resist pattern in the above (2), after the coating film formed on the substrate was exposed to light, the substrate was subjected to an ammonia concentration of 5 ppb.
A line and space pattern having a design line width of 0.26 μm was formed in the same manner except that the film was left in a controlled chamber for 2 hours, and then baked after exposure of the coating film. The line width at the upper end of the pattern was defined as La, and evaluation was performed according to the following criteria. Good: 0.85 × 0.26 μm <La <1.1 × 0.2
6 μm, defective a (thin defect): La ≦ 0.85 × 0.26 μm, defective b (thick defect): La ≧ 1.1 × 0.26 μm

[0072]

[Table 4]

As is clear from the results in Table 4, Example 1
According to Nos. To 15, a high resolution of 0.25 μm or less can be obtained, a resist pattern having an intended pattern shape is formed, and a fine resist pattern is reliably formed even if the PED is long. Was confirmed.

[0074]

According to the method for forming a resist pattern of the present invention, a high resolution can be obtained, a resist pattern having an intended pattern shape can be formed, and even if the PED is long, A fine resist pattern can be reliably formed. Therefore, the method for forming a resist hattern according to the present invention can be suitably used for manufacturing a semiconductor device.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Shinichiro Iwanaga 2--11-24 Tsukiji, Chuo-ku, Tokyo Inside Nippon Gosei Rubber Co., Ltd.

Claims (1)

[Claims] 1. A copolymer having a repeating unit represented by the following formula (1) and a repeating unit represented by the following formula (2): and (B) generating an acid by receiving radiation. Using a radiation-sensitive composition containing a radiation-sensitive acid generator to irradiate a coating film composed of the radiation-sensitive composition with radiation,
Thereafter, a step of baking the coating film at a temperature of 130 to 160 ° C. for 30 seconds or more is provided. Embedded image [In the formula (1), R ¹ represents a hydrogen atom or a methyl group. In the formula (2), R ² represents a hydrogen atom or a methyl group, and R ³ represents a tertiary alkyl group having 4 to 10 carbon atoms. ]