JPH112902A - Radiation-sensitive composition - Google Patents

Abstract

(57) [Abstract] (with revisions) [Problem] Excellent process stability and storage stability.
High-precision fine patterns can be formed stably,
In addition, the present invention provides a chemically amplified positive resist effectively responsive to various radiations such as ultraviolet rays, far ultraviolet rays, and X-rays. SOLUTION: A copolymer (B) comprising 10 to 90 parts by weight of a copolymer (A) containing a repeating unit represented by the general formulas (1) and (2) and a general formula (1) or (3) A radiation-sensitive composition comprising 10 to 90 parts by weight and a radiation-sensitive acid generator. R ₁ represents a hydrogen atom or a methyl group R ₂ represents a hydrogen atom or a methyl group; R ₃ represents a hydrogen atom; a chain alkyl group having 1 to 10 carbon atoms; R ₄ and R ₅ independently represent a chain alkyl group having 1 to 10 carbon atoms; Or any two of R ₃ , R ₄ and R ₅ may be bonded to each other to form a 5- to 7-membered ring. R ₆ represents a hydrogen atom or a methyl group, and Ra represents _a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a radiation-sensitive composition. More specifically, the present invention relates to a radiation-sensitive composition useful as a resist suitable for fine processing using various radiations such as ultraviolet rays, far ultraviolet rays, X-rays or charged particle beams.

[0002]

2. Description of the Related Art 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 a higher degree of integration of integrated circuits. The development of a lithography process capable of stably performing high-precision fine processing with a line width of 0.5 μm or less has been strongly promoted.
However, conventional visible light (wavelength 700 to 400 n
m) or near-ultraviolet rays (wavelength 400 to 300 nm), it is difficult to form such a fine pattern with high precision, and therefore a wider depth of focus can be achieved, which is effective for miniaturizing design rules. Short wavelength (wavelength 3
A lithography process using radiation of less than or equal to 00 nm has been proposed.

A lithography process using such short-wavelength radiation includes, for example, X-rays such as KrF excimer laser (wavelength 248 nm) and ArF excimer laser (wavelength 193 nm), X-rays such as synchrotron radiation, and electron beams. A method using a charged particle beam has been proposed. As a high-resolution resist corresponding to these short-wavelength radiations,
"Chemically amplified resist" has been proposed by Business Machines (IBM), and improvement of this chemically amplified resist is currently being vigorously pursued.

[0004] Such a chemically amplified resist generates an acid by irradiation of a radiation-sensitive acid generator contained therein (hereinafter referred to as "exposure"), and the catalytic action of the acid causes a resist film to be formed. A pattern is formed by utilizing a phenomenon in which a chemical reaction (for example, a change in polarity, decomposition of a chemical bond, a cross-linking reaction, or the like) occurs in the solution and the solubility in a developing solution changes in an exposed portion.

[0005] Among the conventional chemically amplified resists which show relatively good resist performance, an alkali-affinity group in an alkali-soluble resin is replaced with a t-butyl ester group or a t-butoxycarbonyl group as a resin component. Protected resin (see Japanese Patent Publication No. 2-27660), resin in which an alkali-affinity group in an alkali-soluble resin is protected by a silyl group (see Japanese Patent Publication No. 3-44290), and resin components in the alkali-soluble resin Resins in which an alkali-affinity group is protected by a ketal group (see JP-A-7-140666), resins in which an alkali-affinity group is protected by an acetal group (see JP-A-2-161)
No. 436 and JP-A-5-249682 are known.

[0006] However, it has been pointed out that these chemically amplified resists have their own problems, and bring various difficulties in practical use.

The major problem is that the line width of the resist pattern changes or the resist pattern becomes T-shaped due to the post-exposure time delay (hereinafter referred to as "PED") from exposure to post-baking. Can be As a means for solving these problems, a method of blending a resin protected with an acetal group and a resin protected with a t-butoxycarbonyl group (Japanese Patent Laid-Open No. 8-15864).
No. 2) has been proposed and is known to exhibit relatively good resist performance. However, this combination has a problem that, when it is used as a resist solution, if it is stored, the sensitivity changes. Also, pattern shape, sensitivity,
Developability and resolution are insufficient, and further improvement is required from the viewpoint of overall characteristics as a chemically amplified resist.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to effectively respond to various kinds of radiation such as ultraviolet rays, far ultraviolet rays, X-rays or valence rays, and to have excellent sensitivity, resolution, developability, and pattern shape. An object of the present invention is to provide a radiation-sensitive composition which is useful as a chemically amplified positive resist excellent in storage stability.

[0009]

According to the present invention, the object is to provide (A) a copolymer comprising a repeating unit represented by the following formula (1) and a repeating unit represented by the following formula (2): Polymer (hereinafter, referred to as “copolymer (A)”),

[0010]

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Here, R ₁ represents a hydrogen atom or a methyl group.

[0012]

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Here, R ₂ represents a hydrogen atom or a methyl group, and R ₃ represents a hydrogen-containing chain alkyl group having 1 to 10 carbon atoms, a cyclic alkyl group having 3 to 10 carbon atoms, and a hydrogen atom having 6 to 10 carbon atoms.
Wherein R ₄ and R ₅ are independently a chain alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group having 1 to 10 carbon atoms, or an aralkyl group having 7 to 11 carbon atoms; A cyclic alkyl group having 10 carbon atoms, an aryl group having 6 to 10 carbon atoms or an aralkyl group having 7 to 11 carbon atoms, or any two of R ₃ , R ₄ and R ₅ are bonded to each other to form a 5- to 7-membered ring; (B) a copolymer comprising a repeating unit represented by the following formula (3) and a repeating unit represented by the above formula (1) (hereinafter referred to as “copolymer (B)”) )

[0014]

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Here, R ₆ represents a hydrogen atom or a methyl group, and R _a represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and (C) a radiation-sensitive acid generator. This is achieved by a radiation-sensitive composition characterized by: Hereinafter, the present invention will be described in detail, which will clarify the objects, configurations, and effects of the present invention.

Copolymer (A) The copolymer (A) used in the present invention comprises a repeating unit represented by the above formula (1) (hereinafter, referred to as “repeating unit (1)”) It is a copolymer represented by a repeating unit represented by (2) (hereinafter, referred to as “repeating unit (2)”). In the formula (1), R ₁ is a hydrogen atom or a methyl group. In the formula (2), R ₂ is a hydrogen atom or a methyl group. R ₃ represents a hydrogen atom, a chain alkyl group having 1 to 10 (C _{1 to} C ₁₀ ) carbon atoms,
10 (C ₃ -C ₁₀ ) cyclic alkyl group, 6-10 carbon atoms
A (C ₆ -C ₁₀ ) aryl group or a C ₇ -C 11 (C ₇
To C ₁₁ ).

The C ₁ -C ₁₀ chain alkyl group may be linear or branched, for example, methyl, ethyl, n-propyl, i-propyl, n-propyl. Butyl group, i-butyl group, sec-butyl group, t-butyl group,
n-pentyl group, neopentyl group, n-hexyl group, n
-Heptyl group, n-octyl group, 2-ethylhexyl group, n-nonyl group, n-decyl group and the like.

Examples of the C ₃ -C ₁₀ cyclic alkyl group include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, norbornyl, isobornyl and the like.

The C ₆ -C ₁₀ aryl group includes, for example, phenyl, tolyl, xylyl, cumenyl, 1-
Examples include a naphthyl group.

The C ₇ -C ₁₁ aralkyl group includes, for example, benzyl, α-methylbenzyl, phenethyl and naphthylmethyl.

Further, in the formula (2), R ₄ and R ₅ are independently a C ₁ -C ₁₀ chain alkyl group, a C ₁ -C ₁₀ halogenated alkyl group, a C ₃ -C ₁₀ cyclic group. Alkyl group,
It is a C ₆ -C ₁₀ aryl group or a C ₇ -C ₁₁ aralkyl group. Among these, specific examples of the group other than the halogenated alkyl group include the same groups as described above. Examples of the alkyl halide include, for example, a trifluoroethyl group, a hexafluoropropyl group, and heptadecafluorodecyl. And the like.

R ₃ , R ₄ and R ₅ can be bonded to each other to form a 5- to 7-membered ring. The 5- to 7-membered ring when R ₃ and R ₄ are bonded, and examples thereof include a cyclopentyl group, a cyclohexyl group and a cycloheptyl group. Examples of the 5- to 7-membered ring when R ₃ and R ₅ or R ₄ and R ₅ are bonded include a tetrahydrofuranyl group and a tetrahydropyranyl group.

In the above equation (2), the following equation (2) -1

[0024]

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Here, the definitions of R ₃ , R ₄ and R ₅ are the same as those in the above formula (2), and the group represented by is a group called an acetal group or a ketal group. Here, as the acetal group, for example, a 1-methoxyethoxy group,
Ethoxyethoxy group, 1-n-propoxyethoxy group,
1-i-propoxyethoxy group, 1-n-butoxyethoxy group, 1-i-butoxyethoxy group, 1-sec-butoxyethoxy group, 1-t-butoxyethoxy group, 1-
Cyclopentyloxyethoxy group, 1-cyclohexyloxyethoxy group, 1-norbornyloxyethoxy group, 1-bornyloxyethoxy group, 1-phenyloxyethoxy group, 1- (1-naphthyloxy) ethoxy group, 1-benzyl An oxyethoxy group, a 1-phenethyloxyethoxy group, a (cyclohexyl) (methoxy) methoxy group, a (cyclohexyl) (ethoxy) methoxy group,
A (cyclohexyl) (n-propoxy) methoxy group,
A (cyclohexyl) (i-propoxy) methoxy group,
(Cyclohexyl) (cyclohexyloxy) methoxy group, (cyclohexyl) (phenoxy) methoxy group,
(Cyclohexyl) (benzyloxy) methoxy group,
(Phenyl) (methoxy) methoxy group, (phenyl)
(Ethoxy) methoxy group, (phenyl) (n-propoxy) methoxy group, (phenyl) (i-propoxy) methoxy group, (phenyl) (cyclohexyloxy) methoxy group, (phenyl) (phenoxy) methoxy group, (phenyl) (Benzyloxy) methoxy group, (benzyl)
(Methoxy) methoxy group, (benzyl) (ethoxy) methoxy group, (benzyl) (n-propoxy) methoxy group, (benzyl) (i-propoxy) methoxy group, (benzyl) (cyclohexyloxy) methoxy group, (benzyl) Examples thereof include a (phenoxy) methoxy group, a (benzyl) (benzyloxy) methoxy group, a 2-tetrahydrofuranyloxy group, and a 2-tetrahydropyranyloxy group.

Next, examples of the ketal group include 1-methyl-1-methoxyethoxy group, 1-methyl-1-ethoxyethoxy group, 1-methyl-1-n-propoxyethoxy group and 1-methyl-1-methoxyethoxy group. i-propoxyethoxy group,
1-methyl-1-n-butoxyethoxy group, 1-methyl-1-i-butoxyethoxy group, 1-methyl-1-se
c-butoxyethoxy group, 1-methyl-1-t-butoxyethoxy group, 1-methyl-1-cyclopentyloxyethoxy group, 1-methyl-1-cyclohexyloxyethoxy group, 1-methyl-1-norbornyloxy Ethoxy group, 1-methyl-1-bornyloxyethoxy group, 1
-Methyl-1-phenyloxyethoxy group, 1-methyl-1- (1-naphthyloxy) ethoxy group, 1-methyl-1-benzyloxyethoxy group, 1-methyl-1-phenethyloxyethoxy group, 1-cyclohexyl -1-
Methoxyethoxy group, 1-cyclohexyl-1-ethoxyethoxy group, 1-cyclohexyl-1-n-propoxyethoxy group, 1-cyclohexyl-1-i-propoxyethoxy group, 1-cyclohexyl-1-cyclohexyloxyethoxy group, 1 -Cyclohexyl-1-phenoxyethoxy group, 1-cyclohexyl-1-benzyloxyethoxy group, 1-phenyl-1-methoxyethoxy group, 1-phenyl-1-ethoxyethoxy group, 1-phenyl-1-n-propoxyethoxy Group, 1-phenyl-
1-i-propoxyethoxy group, 1-phenyl-1-cyclohexyloxyethoxy group, 1-phenyl-1-phenyloxyethoxy group, 1-phenyl-1-benzyloxyethoxy group, 1-benzyl-1-methoxyethoxy group , 1-benzyl-1-ethoxyethoxy group, 1-benzyl-1-n-propoxyethoxy group, 1-benzyl-1-i-propoxyethoxy group, 1-benzyl-1-
Cyclohexyloxyethoxy group, 1-benzyl-1-
Phenyloxyethoxy group, 1-benzyl-1-benzyloxyethoxy group, 2- (2-methyl-tetrahydrofuranyl) oxy group, 2- (2-methyl-tetrahydropyranyl) oxy group, 1-methoxy-cyclopentyloxy group , 1-methoxy-cyclohexyloxy group and the like.

In the copolymer (A), the repeating units (1) and (2) may be used alone or in combination of two or more. (A) The content of the repeating unit (2) in the copolymer is 10 to 60 mol%, preferably 20 to 60 mol%, based on the total of the repeating units (1) and (2).
It is 50 mol%, more preferably 25 to 45 mol%. If it is less than 10 mol%, the resolution as a resist tends to decrease, while if it exceeds 60 mol%, the sensitivity tends to decrease.

In the copolymer (A), in addition to the repeating unit (1) and the repeating unit (2), a repeating unit of another monomer copolymerizable therewith (hereinafter, referred to as “repeating unit (4)”) ) Can be contained. The repeating unit (4) is copolymerized for improving the pattern shape and the resolution, and is a monomer having low solubility in an alkali developing solution, that is, a sulfonic acid group, a carboxylic acid group,
It is derived from a monomer having no acidic hydroxyl group such as a phenolic hydroxyl group. Examples of such a monomer (hereinafter, referred to as “monomer (4)”) include a vinyl group-containing compound,
(Meth) acrylamide compounds, (meth) acrylic esters and the like can be mentioned.

Here, examples of the vinyl group-containing compound include aromatic vinyl compounds such as styrene, α-methylstyrene, p-methylstyrene, chlorostyrene, and t-butoxystyrene, and heteroatom-containing compounds such as vinylpyrrolidone and vinylcaprolactam. Alicyclic vinyl compounds; and cyano group-containing vinyl compounds such as acrylonitrile and methacrylonitrile. As the (meth) acrylamide compound, for example, acrylamide, methacrylamide, N-
Methylol acrylamide and the like can be mentioned.

Examples of the (meth) acrylic acid esters include alkyl (meth) acrylates such as methyl (meth) acrylate and ethyl (meth) acrylate;
Examples thereof include hydroxyethyl (meth) acrylate, phenyl (meth) acrylate, isobornyl (meth) acrylate, and tricyclodecanyl acrylate.

The preferred content of the repeating unit (4) varies depending on the proportion of the repeating units (1) and (3), but is generally 0 for all the repeating units of the copolymer (A).
-30 mol%, preferably 0-20 mol%, more preferably 5-20 mol%. If it exceeds 40 mol%, the solubility in a developer tends to decrease.

The above copolymer (A) can be produced, for example, by the following method. (A) A vinyl aromatic (co) polymer having a phenolic hydroxyl group (hereinafter referred to as a “phenolic hydroxyl group-containing polymer”) such as poly (p-hydroxystyrene), poly (p-isopropenylphenyl), etc. Prepare and react one part of the hydroxyl groups with a compound such as ethyl vinyl ether, 2,3-dihydropyran, 4-methoxy-5,6-dihydro-2H-pyran or 2-methoxypropylene to etherify A method for producing a polymer comprising the repeating unit of (1) and the repeating unit of the formula (2). (B) with sodium phenoxide derivative of a phenolic hydroxyl group-containing polymer, wherein _{Cl-CH (R 3) (} R 4) OR 5
_{(Wherein, R 3, R 4, R} 5 R 3 is in each formula (2), R _4, R ₅ are the same as) a compound represented by,
A method of etherifying by reacting with sodium chloride. (C) A method of directly copolymerizing a vinyl aromatic compound corresponding to the above formulas (1) and (2).

The weight average molecular weight (hereinafter referred to as “Mw”) of the copolymer (A) in terms of polystyrene determined by gel permeation chromatography (hereinafter referred to as “GPC”).
Is usually from 1,000 to 100,000, preferably from 3,000 to 40,000, and more preferably from 3,000 to 30,000. Molecular weight 1,000
If the amount is less than the above, the sensitivity and heat resistance of the resist are likely to be inferior, and if it exceeds 100,000, the solubility of the radiation-irradiated portion of the resist in the developing solution is likely to be inferior.

Copolymer (B) The copolymer (B) used in the present invention comprises a repeating unit represented by the above formula (3) (hereinafter referred to as “repeating unit (3)”) and a repeating unit It is a copolymer consisting of (1). In the formula (3), R ₆ is a hydrogen atom or a methyl group, and _Ra is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. Specific examples of the alkyl group having 1 to 10 carbon atoms include the above-described chain alkyl groups having 1 to 10 carbon atoms or the cyclic alkyl groups having 3 to 10 carbon atoms.

The repeating unit (1) in the copolymer (B)
Is usually 50 to 95 mol%, preferably 55 to 95 mol%.
It is 90 mol%, more preferably 60 to 80 mol%. If it is less than 50 mol%, the sensitivity as a resist tends to decrease, while if it exceeds 95 mol%, the degree of development tends to decrease.

The repeating unit (3) in the copolymer (B)
Is usually 5 to 50 mol%, preferably 10 to 4 mol%.
It is 5 mol%, more preferably 20 to 40 mol%.
If it is less than 5 mol%, the resolution as a resist tends to decrease, while if it exceeds 50 mol%, the developability tends to decrease.

In the copolymer (B), in addition to the repeating unit (1) and the repeating unit (3), a repeating unit of another monomer copolymerizable therewith (hereinafter, referred to as “repeating unit (5)”) ) Can be contained. The repeating unit (5) is copolymerized for improving the pattern shape and the resolution, and is a monomer having low solubility in an alkali developing solution, that is, a sulfonic acid group, a carboxylic acid group,
It is derived from a monomer having no acidic hydroxyl group such as a phenolic hydroxyl group. Examples of such a monomer (hereinafter, referred to as “monomer (4)”) include a vinyl group-containing compound,
(Meth) acrylamide compounds, (meth) acrylic esters and the like can be mentioned. Here, examples of the vinyl group-containing compound include aromatic vinyl compounds such as chlorostyrene and t-butoxystyrene, heteroatom-containing alicyclic vinyl compounds such as vinylpyrrolidone and vinylcaprolactam; and cyano groups such as acrylonitrile and methacrylonitrile. Vinyl compounds. As the (meth) acrylamide compound, for example, acrylamide,
Examples thereof include methacrylamide and N-methylolacrylamide.

Examples of the (meth) acrylic esters include alkyl (meth) acrylates such as methyl (meth) acrylate and ethyl (meth) acrylate;
Examples thereof include hydroxyethyl (meth) acrylate and phenyl (meth) acrylate. The preferred content of the repeating unit (5) varies depending on the proportion of the repeating units (1) and (3), but is generally less than 30 mol% based on all the repeating units of the copolymer (A). 30
If it exceeds mol%, the solubility in a developer tends to decrease.

The copolymer (B) can be prepared, for example, by the following (d)
To (f). (D) A method in which a vinyl aromatic compound corresponding to the above formulas (1) and (3) is directly subjected to radical copolymerization. (E) A method of copolymerizing t-butoxystyrene and a vinyl aromatic compound corresponding to the above formula (3), followed by hydrolysis with an acid. (F) A method of copolymerizing acetoxystyrene and a vinyl aromatic compound corresponding to the above formula (3), followed by hydrolysis with an alkali.

(B) The Mw of the copolymer is usually 1,000
~ 100,000, preferably from 3,000 to 40,000
3,000, more preferably 3,000 to 30,00.
0. When the molecular weight is less than 3,000, sensitivity and heat resistance are liable to deteriorate when used as a resist.
If it exceeds 000, the solubility of the irradiated portion of the resist in the developing solution tends to be poor. These copolymers (B) may be used alone or as a mixture of two or more.

In the present invention, the copolymer (A) and the copolymer (B) are used in a ratio of copolymer (A) to polymer (B).
Is 50/50 to 95/5, preferably 60/4
0-90 / 10, more preferably 70 / 30-90 /
It is 10. In addition, these weight ratios are based on the copolymer (A).
And the total weight of the copolymer (B) is 100 parts by weight.

Radiation-Sensitive Acid Generator A radiation-sensitive acid generator is a compound that generates an acid upon irradiation. As the radiation-sensitive acid generator used in the present invention, onium salts, sulfone compounds,
Sulfonate compounds, sulfonimide compounds and the like can be mentioned. Examples of these radiation-sensitive acid generators are shown below.

Onium salts: Examples of onium salts include iodonium salts, sulfonium salts, phosphonium salts,
Examples thereof include diazonium salts, ammonium salts, and pyridinium salts. Specific examples of the onium salt compound include diphenyliodonium trifluoromethanesulfonate, diphenyliodonium pyrene sulfonate,
Diphenyliodonium dodecylbenzenesulfonate, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium tosylate, diphenyliodonium hexafluoroantimonate, triphenylsulfonium naphthalene sulfonate, triphenylsulfonium camphor sulfonate, (hydroxyphenyl) benzylmethylsulfonium toluenesulfonate, di- (T-butylphenyl) iodonium nonafluorobutanesulfonate, di- (t-butylphenyl) iodoniumtoluenesulfonate, di-
(T-butylphenyl) iodonium camphorsulfonate, di- (t-butylphenyl) iodonium naphthalene sulfonate and the like can be mentioned.

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

Sulfonate compound: Examples of the sulfonic acid ester compound include alkylsulfonic acid esters, haloalkylsulfonic acid esters, arylsulfonic acid esters, and iminosulfonates. Specific examples of the sulfonic acid ester compound include benzoin tosylate, pyrogallol tris (trifluoromethane sulfoate), pyrogallol methanesulfonic acid triester, nitrobenzyl-9,10-diethoxyanthracene-2-sulfonate, α-methylol benzoin tosylate Rate, α-methylol benzoin octane sulfonic acid ester, α-methylol benzoin trifluoromethane sulfonic acid ester, α-methylol benzoindodecyl sulfonic acid ester, and the like.

Sulfonimide compound: As the sulfonimide compound, for example, the following formula (4)

[0047]

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Here, X represents a divalent group such as an alkylene group, an arylene group, or an alkoxylene group, and R ₇ represents a monovalent group such as an alkyl group, an aryl group, a halogen-substituted alkyl group, or a halogen-substituted aryl group. And the compound represented by

Specific examples of the sulfonimide compound include:
N- (trifluoromethylsulfonyloxy) succinimide, N- (trifluoromethylsulfonyloxy)
Phthalimide, N- (trifluoromethylsulfonyloxy) diphenylmaleimide, N- (trifluoromethylsulfonyloxy) bicyclo [2.2.1] hept-5
-Ene-2,3-dicarboximide, N- (trifluoromethylsulfonyloxy) -7-oxabicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (tri Fluoromethylsulfonyloxy)
Naphthylimide, N- (trifluoromethylsulfonyloxy) bicyclo [2.2.1] heptane-5,6-oxy-2,3-dicarboximide, N- (camphorsulfonyloxy) succinimide, N- (camphorsulfonyl) Oxy) 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- (trifluoromethylsulfonyloxy) -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-fluorophenylsulfonyloxy) naphthyldicarboximide and the like.

Of the above-mentioned radiation-sensitive acid generators, onium salts and sulfone compounds are preferable, and in particular, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium naphthalene sulfonate, triphenylsulfonium camphorsulfonate, bis (phenylsulfonyl) cyclohexane, bis ( Phenylsulfonyl) cyclopentene, di- (t-butylphenyl)
Iodonium nonafluorobutanesulfonate, di-
(T-butylphenyl) iodonium tosylate, di-
(T-butylphenyl) iodonium camphorsulfonate, di- (t-butylphenyl) iodonium naphthalene sulfonate and the like are preferred.

In the present invention, the above-mentioned radiation-sensitive acid generator is usually used in a total amount of 1% of the copolymer (A) and the copolymer (B).
1 to 20 parts by weight, particularly preferably 1 to 20 parts by weight, per 100 parts by weight
Used in a proportion of 10 parts by weight. These radiation-sensitive acid generators (hereinafter, referred to as “acid generators”) are used alone or in combination of two or more.

Acid Diffusion Control Agent In the present invention, the effect of further controlling the diffusion phenomenon of the acid generated from the acid generator by irradiation of the radiation in the resist film, thereby suppressing undesired chemical reactions in the unirradiated light region. It is preferable to add an acid diffusion controller having the following formula: By using such an acid diffusion controller, the storage stability of the composition is improved, the resolution as a resist is improved, and the line width change of the resist pattern due to the fluctuation of the PED can be suppressed. It is extremely excellent in properties. 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 the following formula (6): R ₁₀ R ₁₁ R ₁₂ N (6) wherein R ₁₀ , R ₁₁ and R ₁₂ are each independently a hydrogen atom, an alkyl group, an aryl group Or a compound represented by an aralkyl group (hereinafter referred to as “nitrogen-containing compound (I)”
That. ), Diamino compounds having two nitrogen atoms in the same molecule (hereinafter referred to as “nitrogen-containing compound (II)”),
Polyamino polymer having three or more nitrogen atoms (hereinafter, referred to as
It is called "nitrogen-containing compound (III)". ), Amide group-containing compounds, urea compounds, nitrogen-containing heterocyclic compounds and the like.

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

Examples of the nitrogen-containing compound (II) include ethylenediamine, N, N, N ', N'-tetramethylethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4'-diaminodiphenylmethane,
4,4'-diaminodiphenyl ether, 4,4'-diaminobenzophenone, 4,4'-diaminodiphenylamine, 2,2'-bis (4-aminophenyl) propane, 2- (3-aminophenyl) -2- ( 4-aminophenyl) propane, 2- (4-aminophenyl) -2-
(3-hydroxyphenyl) propane, 2- (4-aminophenyl) -2- (4-hydroxyphenyl) propane, 1,4-bis [1- (4-aminophenyl) -1-
Methylethyl] benzene, 1,3-bis [1- (4-aminophenyl) -1-methylethyl] benzene and the like can be mentioned.

Examples of the nitrogen-containing compound (III) include polymers of polyethyleneimine, polyallylamine and dimethylaminoethylacrylamide. Examples of the amide group-containing compound include formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N-methylacetamide,
N, N-dimethylacetamide, propionamide, benzamide, pyrrolidone, N-methylpyrrolidone and the like can be mentioned. Examples of the urea compound include urea, methylurea, 1,1-dimethylurea, 1,3-
Dimethylurea, 1,1,3,3-tetramethylurea,
Examples thereof include 1,3-diphenylurea and tributylthiourea.

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 and 2-methylpyridine. Ethylpyridine, 4-ethylpyridine, 2-phenylpyridine, 4-phenylpyridine, N
Pyridines such as -methyl-4-phenylpyridine, nicotine, nicotinic acid, nicotinamide, quinoline, 8-oxyquinoline, 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. Further, among the nitrogen-containing compounds (I), trialkylamines are particularly preferable, and among the nitrogen-containing heterocyclic compounds, pyridines are particularly preferable.

In the present invention, the acid diffusion controlling agents can be used alone or in combination of two or more. The amount of the acid diffusion controller used in the present invention is usually 15 parts by weight or less, preferably 0.001 to 10 parts by weight, more preferably 0 parts by weight, per 100 parts by weight of the total weight of the copolymers (A) and (B). 0.005 to 5 parts by weight. In this case, when the use amount of the acid diffusion controller exceeds 15 parts by weight, the sensitivity as a resist and the developability of an exposed portion tend to decrease. In addition,
If the amount of the acid diffusion controller is less than 0.001 part by weight, the pattern shape and dimensional fidelity as a resist may be reduced depending on the process conditions.

Alkali-Soluble Resin In the present invention, an alkali-soluble resin other than the copolymer (A) and the copolymer (B) may be added, if necessary. The alkali-soluble resin is a resin which is soluble in an alkali developing solution and has at least one kind of a functional group having an affinity for an alkali developing solution, for example, a phenolic hydroxyl group or a carboxyl group. By using such an alkali-soluble resin, it becomes easier to control the dissolution rate of the resist film in the alkali developing solution by the composition of the present invention, so that the developability can be further improved.

Such an alkali-soluble resin is not particularly limited as long as it is soluble in an alkali developer. Preferred alkali-soluble resins include, for example, hydroxystyrene, isopropenylphenol, vinylbenzoic acid, carboxymethyl Polymerization of at least one monomer having an acidic functional group such as styrene, carboxymethoxystyrene, (meth) acrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, mesaconic acid, and cinnamic acid Examples thereof include an addition polymerization resin containing a repeating unit in which a heavy bond is cleaved, and a polycondensation resin containing a condensation repeating unit having an acidic functional group represented by a novolak resin.

The alkali-soluble resin comprising the addition polymerization resin may be composed of only a repeating unit in which the polymerizable double bond portion of the monomer having an acidic functional group is cleaved. As long as it is soluble in an alkali developer, it may further contain one or more other repeating units. Such other repeating units include, for example, styrene, α-methylstyrene, vinyltoluene,
Maleic anhydride, (meth) acrylonitrile, crotonitrile, maleinitrile, fumaronitrile, mesaconitrile, citraconitrile, itaconitrile,
Monomers of (meth) acrylamide, crotonamide, maleamide, fumaramide, mesaconamide, citraconamide, itaconamide, vinylaniline, vinylpyridine, N-vinyl-ε-caprolactam, N-vinylpyrrolidone, N-vinylimidazole and the like Examples include a repeating unit in which a polymerizable double bond is cleaved.

Among the above addition-polymer resins, poly (hydroxystyrene) and poly (isopropenylphenol) are particularly preferred from the viewpoints of high radiation permeability when formed into a resist film and excellent dry etching resistance. . Further, the alkali-soluble resin composed of the polycondensation-based resin may be composed of only the polycondensation-based repeating unit having an acidic functional group, but as long as the generated resin is soluble in an alkali developer, other May be further contained. Such polycondensation resins include, for example, one or more phenols and one or more aldehydes, optionally together with a polycondensation component capable of forming another polycondensation repeating unit, and an acidic or basic catalyst. Can be produced by (co) polycondensation in an aqueous medium or a mixed medium of water and a hydrophilic solvent.

Examples of the phenols include o-cresol, m-cresol, p-cresol and 2,3-
Xylenol, 2,4-xylenol, 2,5-xylenol, 3,4-xylenol, 3,5-xylenol,
Examples of the aldehydes include 2,3,5-trimethylphenol and 3,4,5-trimethylphenol. Examples of the aldehydes include formaldehyde, trioxane, paraformaldehyde, benzaldehyde, acetaldehyde, propylaldehyde, and phenylacetaldehyde. Can be mentioned. The amount of the alkali-soluble resin used in the present invention is usually 200 parts by weight or less per 100 parts by weight of the total of the copolymer (A) and the copolymer (B).

Surfactant In the composition of the present invention, a surfactant can be added. Examples of the surfactant include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, and polyoxyethylene. Octyl phenol ether, polyoxyethylene nonyl phenol ether, polyethylene glycol dilaurate and polyethylene glycol distearate can be mentioned.
F301, EF303, EF352 (manufactured by Tochem Products), Megafax F171, F173 (manufactured by Dainippon Ink Co., Ltd.), Florad FC430, FC431
(Manufactured by Sumitomo 3M Limited), Asahi Guard AG71
0, Surflon S-382, SC101, SC102,
SC103, SC104, SC105, SC106 (manufactured by Asahi Glass Co., Ltd.), organosiloxane polymer KP34
1 (manufactured by Shin-Etsu Chemical Co., Ltd.), polyflow No. 75 which is an acrylic acid or methacrylic acid (co) polymer,
No. 95 (trade name, manufactured by Kyoeisha Yushi Kagaku Kogyo KK) or the like is used.

The mixing amount of the surfactant is usually per 100 parts by weight of the total amount of the copolymer (A) and the copolymer (B).
Not more than 2 parts by weight.

Sensitizer A sensitizer can be added to the composition of the present invention. The sensitizer absorbs the energy of the radiation and transmits the energy to the radiation-sensitive acid generator, thereby exhibiting the action of increasing the amount of acid generated, and is formed by the composition of the present invention. This has the effect of improving the apparent sensitivity of the resist. Examples of preferred sensitizers include benzophenones, rose bengals, anthracenes and the like. The compounding amount of these sensitizers is usually 50 parts by weight or less per 100 parts by weight of the total of the copolymer (A) and the copolymer (B) in the composition.

Other Additives The composition of the present invention, by blending a dye and / or a pigment, makes it possible to visualize a latent image in a radiation-irradiated portion, to reduce the influence of halation at the time of radiation, and to use an adhesion aid. By blending, the adhesiveness with the substrate can be further improved. Further, as other additives, an antihalation agent such as 4-hydroxy-4′-methylchalcone, a shape improver, a storage stabilizer, an antifoaming agent, and the like can be blended.

Solvent When the composition of the present invention is used, it is uniformly dissolved in a solvent such that the total solid content is, for example, 5 to 50% by weight, preferably 15 to 40% by weight. By filtering through a filter of about 0.2 μm,
It is prepared as a composition solution.

Examples of the 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 ether. Propylene glycol monoalkyl ethers such as 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 monoalkyl ether acetates such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate; methyl lactate, ethyl lactate, n-lactic acid n
Lactates such as -propyl and isopropyl lactate; n-amyl formate, isoamyl formate, ethyl acetate, n-acetate
Aliphatic carboxylic acid esters such as propyl, isopropyl acetate, n-butyl acetate, isobutyl acetate, n-amyl acetate, isoamyl acetate, isopropyl propionate, n-butyl propionate and isobutyl propionate;

Ethyl hydroxyacetate, 2-hydroxy-
Ethyl 2-methylpropionate, 2-hydroxy-3-
Methyl methyl butyrate, ethyl methoxyacetate, ethyl ethoxyacetate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, 3-methoxybutyl acetate, 3-methyl- 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl propionate, 3-methyl-3-methoxybutyl butyrate, methyl acetoacetate, ethyl acetoacetate, methyl pyruvate,
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; lactones such as γ-butyrolactone.

Formation of Resist Pattern When forming a resist pattern from the composition of the present invention,
The composition solution prepared as described above, spin coating, casting coating, by a suitable coating means such as roll coating, for example, silicon wafer, by coating on a substrate such as a wafer coated with aluminum, After forming a resist film and performing a heat treatment (hereinafter, referred to as “pre-bake”) in advance, irradiation with radiation (hereinafter, referred to as “exposure”) is performed through a predetermined mask pattern.
The radiation used at that time is, for example, ultraviolet rays such as i-ray (wavelength 365 nm); ArF excimer laser (wavelength 193 nm), depending on the type of the radiation-sensitive acid generator.
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 are appropriately selected and used. Exposure conditions such as the exposure amount are appropriately selected according to the composition of the composition of the present invention, the type of each additive, and the like.

In the present invention, in order to improve the apparent sensitivity of the resist film, a heat treatment (hereinafter, referred to as a heat treatment) is performed after the exposure.
This is called “post-exposure bake”. ) Is preferred. The heating conditions vary depending on the composition of the composition of the present invention, the type of each additive and the like, but are usually 30 to 200 ° C, preferably 40 to 150 ° C. Next, the exposed resist film is treated with an alkali developing solution, usually at 10 to 50 ° C. and 30 to 2 ° C.
A predetermined resist pattern is formed by alkali development under the condition of 00 seconds.

Examples of the alkali developer include alkali metal hydroxides; aqueous ammonia; mono-, di- or tri-alkylamines; mono-, di- or tri-alkanolamines; Tetraalkylammonium hydroxides; Choline; 1,8-
Diazabicyclo- [5.4.0] -7-undecene, 1,
An alkaline aqueous solution in which an alkaline compound such as 5-diazabicyclo- [4.3.0] -5-nonene is dissolved in a concentration of usually 1 to 10% by weight, preferably 1 to 5% by weight is used. . In addition, 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 an alkaline aqueous solution is used, washing is generally performed after development. In forming the resist pattern, a protective film may be provided on the resist film in order to prevent the influence of basic impurities and the like contained in the environmental atmosphere.

[0075]

The present invention will be described below more specifically with reference to examples and comparative examples. However, the present invention is not limited to these embodiments. Here, the measurement of Mw and the evaluation of each resist were performed in the following manner.

A GPC column manufactured by Mw Tosoh Corporation (two G2000HXL,
G3000HXL one, G4000HXL one)
The measurement was performed by gel permeation chromatography using monodisperse polystyrene as a standard under the analysis conditions of a flow rate of 1.0 ml / min, an elution solvent of tetrahydrofuran, and a column temperature of 40 ° C.

The line-and-space pattern (1L1S) having a line width of 0.3 μm when the sensitivity resist pattern was formed is one-to-one.
The exposure amount formed at the line width of was set as the optimum exposure amount, and the sensitivity was evaluated based on the optimum exposure amount.

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

In a line and space pattern having a pattern shape of 0.3 μm, when the line width at the upper part of the pattern is La and the line width at the lower part of the pattern is Lb, 0.9 × Lb <La <1.1 × Lb is preferable. , 0.9 × Lb ≧ La when round top, La
The case of ≧ 1.1 × Lb was represented as T-type.

A resist film of the developable composition was formed, and the scum after pattern formation and the degree of undeveloped portion were examined using a scanning electron microscope. A storage-stable composition was prepared, and the sensitivity immediately after preparation and the sensitivity after storage at 35 ° C. for 3 weeks were measured and examined.

Synthesis of Copolymer (A) Synthesis Example 1 Poly (p-hydroxystyrene) (Mw 12,000)
After dissolving 24 g in 100 ml of dioxane,
Bubbling was performed with nitrogen for 30 minutes. To this solution, 8 g of ethyl vinyl ether and 1 g of pyridinium p-toluenesulfonate as a catalyst were added and reacted for 12 hours.
This reaction solution is dropped into a 1% by weight aqueous ammonia solution,
The copolymer was precipitated. The polymer was dried in a vacuum oven at 50 ° C. overnight. The obtained copolymer had Mw of 1
It was 6,000, and as a result of ¹³ C-NMR measurement, it had a structure in which 45% of the hydrogen atoms of the phenolic hydroxyl group were substituted with a 1-ethoxyethyl group. This copolymer is referred to as a polymer A-1.

Synthesis Example 2 Poly (p-hydroxystyrene) (Mw 8,000) 2
After dissolving 4 g in 100 ml of dioxane, bubbling was performed with nitrogen for 30 minutes. 2,3-
7.5 g of dihydropyran and 0.4 g of pyridinium p-toluenesulfonate as a catalyst were added and reacted for 6 hours. This reaction solution was added dropwise to a 1% aqueous ammonia solution to precipitate a copolymer. The copolymer was dried in a vacuum dryer at 50 ° C. overnight. The obtained copolymer is Mw
Was 11,000, and as a result of ¹³ C-NMR measurement, 42% of the hydrogen atoms of the phenolic hydroxyl group were substituted with a tetrahydropyranyl group. This copolymer is referred to as a polymer A-2.

Synthesis Examples 3 to 6 In the same manner as in Synthesis Example 1, respective copolymers were synthesized using the phenolic hydroxyl group-containing polymers shown in Table 1 and the vinyl ether compounds shown in Table 1. Table 1 shows the analysis values of the copolymer. This copolymer is referred to as polymers A-3 to A-5.

[0084]

[Table 1]

Synthesis Example 7 of Copolymer (B) Synthesis Example 7 30 g of p-acetoxystyrene and 10 g of styrene were mixed with 50 g of dioxane to form a homogeneous solution. After bubbling this solution with nitrogen for 30 minutes, 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile)
1.9 g was added, and polymerization was carried out for 7 hours while maintaining the reaction temperature at 60 ° C. while continuing bubbling. After completion of the polymerization, the reaction solution was mixed with a large amount of hexane to coagulate the produced copolymer. Next, after redissolving the copolymer in dioxane, the operation of coagulating again with hexane is repeated several times to completely remove unreacted monomers and drying under reduced pressure at 50 ° C. to obtain a white copolymer. A coalescence was obtained. Next, the copolymer was dissolved again in 100 g of dioxane, and 20 g of 10% sulfuric acid aqueous solution was added.
And hydrolyzed at 80 ° C. for 6 hours. 100 g of ethyl acetate was added to the solution, then 100 g of distilled water was added, and the mixture was shaken well, allowed to stand, and the aqueous layer was discarded. Thereafter, washing with water was repeated until the pH of the aqueous layer became neutral. Subsequently, coagulation was carried out in a large amount of hexane, followed by vacuum drying to obtain a white powder. The obtained copolymer had Mw of 9,000 and ¹
As a result of 1 H-NMR measurement, the copolymerization molar ratio of p-hydroxystyrene and styrene was 70:30. This copolymer is referred to as a polymer B-1.

Synthesis Example 8 In the same manner as in Synthesis Example 7, 30 g of p-butoxystyrene and 5.3 g of styrene were polymerized, unreacted substances were removed, and acid decomposition was carried out. Mw was 7,000, and hydroxystyrene and styrene were used. Was obtained at a copolymerization molar ratio of 80:20. This copolymer is referred to as a polymer B-2.

Synthesis Example 9 In the same manner as in Synthesis Example 7, 28 g of p-butoxystyrene and 30 g of styrene were polymerized, unreacted substances were removed, and acid decomposition was carried out.
A copolymer having Mw of 7,000 and a copolymerization molar ratio of hydroxystyrene and styrene of 60:40 was obtained. This copolymer is referred to as a polymer B-3.

Synthesis Example 10 Poly (p-hydroxystyrene) (Mw 8,000) 2
After dissolving 4 g in 100 ml of dioxane, bubbling was performed with nitrogen for 30 minutes. 50 g of triethylamine was added to this solution, 6.5 g of di-t-butyl dicarbonate was added at 5 ° C. with stirring, and the mixture was reacted for 6 hours. Thereafter, the reaction solution was dropped into a 1% by weight aqueous ammonia solution to precipitate a copolymer. The copolymer was dried in a vacuum dryer at 50 ° C. overnight. The obtained copolymer is represented by M
w was 11,000, and as a result of ¹³ C-NMR measurement, 25% of the hydrogen atoms of the phenolic hydroxyl group were substituted with a t-butoxycarbonyl group. This copolymer is referred to as a polymer C-1.

Examples 1 to 10 and Comparative Examples 1 to 3 Each component shown in Table 3 (parts are based on weight) was mixed to obtain a uniform solution, which was then filtered through a membrane filter having a pore size of 0.2 μm. , A composition solution was prepared. Thereafter, each composition solution was spin-coated on a silicon wafer, and prebaked at 90 ° C. for 120 seconds to obtain a film thickness of 1.
A 0 μm resist film was formed. Next, a KrF excimer laser (Stepper NSR-20 manufactured by Nikon Corporation) is used.
05EX8A) at 100 ° C.
After baking after exposure for 60 seconds, a 2.38% by weight aqueous solution of tetramethylammonium hydroxide was used.
Paddle development was performed at 3 ° C. for 1 minute, washed with pure water, and dried to form a resist pattern. Table 4 shows the evaluation results of the respective resists.

[0090]

[Table 2]

[0091]

[Table 3]

Here, the radiation-sensitive acid generator, acid diffusion controller and solvent in each of Examples and Comparative Examples are as follows. Radiation-sensitive acid generator (acid generator) C-1: triphenylsulfonium trifluoromethanesulfonate C-2: triphenylsulfonium camphorsulfonate *) C-3: bis (phenylsulfonyl) cyclohexane *) C-2 is as follows: It is a compound having a structural formula.

[0093]

Embedded image

Acid Diffusion Control Agent A : Nicotinic acid amide b: Tri-n-butylamine

Solvent EL: ethyl lactate MMP: methyl 3-methoxypropionate PGMEA: propylene glycol monomethyl ether acetate

[0096]

The radiation-sensitive composition of the present invention is particularly excellent in sensitivity, resolution, developability and pattern shape, and also excellent in storage stability of sensitivity. Moreover, the radiation-sensitive composition of the present invention effectively responds to various radiations such as ultraviolet rays, far ultraviolet rays, X-rays and charged particle beams,
It is extremely useful as a chemically amplified positive resist. Therefore, the radiation-sensitive composition of the present invention can be suitably used for manufacturing semiconductor devices, which are expected to be further miniaturized in the future.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshihisa Ota 2--11-24 Tsukiji, Chuo-ku, Tokyo Inside Nippon Gosei Rubber Co., Ltd.

Claims (1)

[Claims] 1. A copolymer comprising a repeating unit represented by the following formula (1) and a repeating unit represented by the following formula (2): Here, R ₁ represents a hydrogen atom or a methyl group. Here, R ₂ represents a hydrogen atom or a methyl group, and R ₃ represents a hydrogen atom, a linear alkyl group having 1 to 10 carbon atoms,
A cyclic alkyl group having 10 carbon atoms, an aryl group having 6 to 10 carbon atoms or an aralkyl group having 7 to 11 carbon atoms, wherein R ₄ and R ₅ are each independently a chain alkyl group having 1 to 10 carbon atoms, A halogenated alkyl group of 10, a cyclic alkyl group of 3 to 10 carbon atoms, an aryl group of 6 to 10 carbon atoms or an aralkyl group of 7 to 11 carbon atoms, or any one of R ₃ , R ₄ and R ₅ (B) a repeating unit containing a repeating unit represented by the following formula (3) and a repeating unit represented by the above formula (1), which may be bonded to each other to form a 5- to 7-membered ring; Polymer embedded image Here, R ₆ represents a hydrogen atom or a methyl group, and Ra represents _a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and (C) a radiation-sensitive acid generator. Radiation-sensitive composition.