JP2003301006A - Production method of polymer for resist and positive- type radiation sensitive composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of producing a polymer for resist having high sensitivity, high resolution and characteristics hardly affected by environmental conditions as well, and a positive-type radiation sensitive composition enabling processing of a fine pattern with good shape at a low light exposure. <P>SOLUTION: The method of producing the polymer for resist is characterized by polymerizing a monomer by adding a chain transfer agent having at least one nitrogen atom. The positive-type radiation sensitive composition includes a polymer which is produced by the method and is turned to be an alkali-soluble by the action of an acid, and an acid generator which generates an acid by the irradiation with radiation rays. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positive type radiation sensitive composition used for manufacturing semiconductor integrated circuits, lithography masks and the like.

[0002]

2. Description of the Related Art In recent years, in the field of manufacturing semiconductor integrated circuits, lithographic masks and the like, finer patterns have been progressing as the degree of integration is improved. In order to realize this miniaturization, a resist with high sensitivity and high resolution has been required. Furthermore, it is difficult to perform such fine processing by lithography using a light source having a comparatively long wavelength as in the conventional art, and far ultraviolet rays, vacuum ultraviolet rays, and
Lithography using X-rays and electron beams has been studied, and a resist corresponding to such a light source is required.

Conventionally, as a resist in this field, a main chain cutting type resist using an acrylic polymer has been known. The main chain cleavage type resist is a resist that utilizes a mechanism in which the main chain of a polymer is cleaved by exposure to light and the molecular weight is reduced to change the dissolution rate in a developing solution.

In recent years, a chemically amplified resist has been actively studied as a known resist material having high sensitivity and high resolution. The chemically amplified resist is a resist having a mechanism in which an acid is generated in an exposed area by the action of a photoacid generator and the solubility of the exposed area is changed by the catalytic action of this acid. As such a chemically amplified resist,
A resist composed of a polymer obtained by protecting an alkali-affinity group in an alkali-soluble polymer with a t-butyl group, a t-butoxycarbonyl group, an acetal group and the like is known. Further, Japanese Patent Laid-Open No. 2001-2735 discloses a method for producing a chemically amplified resist polymer, in which a chain transfer agent having a specific structure is used for polymerization to reduce the molecular weight of the polymer.

[0005]

The chemically amplified resist can form a pattern with high sensitivity and high resolution as compared with the main chain cleavage type resist, but has a drawback that it is easily affected by the environment. Specifically, when a basic substance is present in the air, the acid on the resist film surface in the exposed area is deactivated,
The upper part of the pattern is left unmelted to form a T-top shape. For this problem, attempts have been made to add a low molecular weight compound such as a basic compound to the resist, but the effect cannot be said to be sufficient. Even when the resist material described in JP 2001-2735 A was used, the obtained pattern had a T-top shape.

An object of the present invention is to provide a method for producing a resist polymer having high sensitivity, high resolution, and characteristics which are not easily influenced by the environment, and a polymer produced by this method, which is suitable for low exposure dose. It is an object of the present invention to provide a positive radiation-sensitive composition capable of processing a fine pattern in shape.

[0007]

That is, the present invention is a method for producing a resist polymer, which comprises polymerizing a monomer by adding a chain transfer agent containing at least one nitrogen atom. The present invention relates to a positive-type radiation-sensitive composition containing the polymer and an acid generator that generates an acid upon irradiation with radiation.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.

In the method for producing a resist polymer of the present invention, a monomer is polymerized by adding a chain transfer agent containing at least one nitrogen atom, preferably a chain transfer agent containing at least one basic nitrogen-containing structure. It is characterized by

Here, the chain transfer agent is a compound added for the purpose of reducing the molecular weight of the polymer in radical polymerization. That is, by adding a chain transfer agent to a polymerization system composed of a monomer and a polymerization initiator to carry out polymerization, a growth polymer radical (P.) and a chain transfer agent (A-
A radical transfer reaction occurs with B), the growing polymer becomes P-B, the polymerization is stopped, and the polymerization is restarted from the chain transfer agent (A.) to which the radical is transferred. Since the polymerization of the polymer is stopped in the middle of the process, the molecular weight decreases, and at the end of the polymer, groups derived from the chain transfer agent (A and B)
Will be introduced.

In the present invention, the polymerization is carried out by adding a chain transfer agent containing at least one basic nitrogen-containing structure.
A basic nitrogen-containing structure can be introduced at the polymer terminal. In other words, since the polymer end can be made basic, it is less susceptible to the influence of a trace amount of basic substances in the air without adding a low molecular weight compound such as a basic compound that may be volatilized during baking. can do.

The chain transfer agent of the present invention is not particularly limited as long as it is a compound containing at least one nitrogen atom, but thiols, disulfides and thiosulfonic acid esters are preferable.

The thiols containing at least one nitrogen atom are preferably compounds represented by the general formula (1).

[0014]

[Chemical 4]

In the formula, R ¹ represents an organic group containing at least one nitrogen atom, preferably an organic group containing at least one basic nitrogen structure.

Specific examples of thiols include 2-aminoethanethiol, 2-aminopropanethiol, 3-aminopropanethiol, 2- (methylamino) ethanethiol, 2- (ethylamino) ethanethiol, 2-
(Dimethylamino) ethanethiol, 2- (diethylamino) ethanethiol, 2- (dimethylamino) propanethiol, 2- (diethylamino) propanethiol, 3- (dimethylamino) propanethiol, 3-
(Diethylamino) propanethiol, 2- (diisopropylamino) ethanethiol, N-mercaptomorpholine, N-mercaptopiperidine, 4-mercaptopiperidine, 2-mercaptoimidazole, 2-mercapto-1-methylimidazole, 2-mercaptobenzimidazole, Examples include (2-mercaptoethyl) trimethylammonium hydroxide, thioglycolic acid amide, thioglycolic acid dimethylamide, and thioglycolic acid diethylamide.

The disulfide containing at least one nitrogen atom is preferably a compound represented by the general formula (2).

[0018]

[Chemical 5]

In the formula, R ² and R ³ are at least one nitrogen atom.
Represents an organic group containing one, preferably an organic group containing at least one basic nitrogen structure. Also, R ² and R ³
May be the same or different from each other. In the present invention, the organic group containing at least one nitrogen atom is R ² ,
It suffices if it is present in at least one of R ³ , and R ² ,
It may be present in any of R ³ .

Specific examples of disulfides include 2,
2'-dithiodianiline, 4,4'-dithiodianiline, 2,2'-dithio (N, N-dimethyl) aniline,
4,4'-dithio (N, N-dimethyl) aniline, 2,
2'-dithio (N, N-diethyl) aniline, 4,4 '
-Dithio (N, N-diethyl) aniline, N, N'-dithiodimorpholine, N, N'-dithiodipiperidine,
4,4'-dithiodipiperidine, N, N'-dithiodipyridine, 4,4'-dithiodipyridine, 2,2'-dithiodibenzoic acid dimethylamide, 4,4'-dithiodibenzoic acid dimethylamide, 2 , 2'-dithiodibenzoic acid diethylamide, 4,4'-dithiodibenzoic acid diemethylamide, and bis (2-benzamidophenyl) disulfide.

Specific examples of thiosulfonic acid esters include benzenethiosulfonic acid-p-aminobenzene, benzenethiosulfonic acid-p- (dimethylamino) benzene, and benzenethiosulfonic acid-p- (diethylamino).
Examples thereof include benzene, p-aminobenzene thiosulfonate benzene, p- (dimethylamino) benzene thiosulfonate benzene, and p- (diethylamino) benzene thiosulfonate benzene.

Further, the positive-type radiation-sensitive composition of the present invention is produced by a method using the above-mentioned chain transfer agent, and is a polymer which becomes alkali-soluble by the action of an acid, and an acid which generates an acid upon irradiation with radiation. It is characterized by containing a generator.

The polymer of the present invention is not particularly limited as long as it is a polymer produced by the method using the above chain transfer agent and becomes alkali-soluble by the action of acid, but is preferably represented by the general formula (3). Polymers containing the structural units are included.

[0024]

[Chemical 6]

In the formula, X represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a halogen element, or a cyano group, and R ^{4 to} R ⁶ are alkyl groups having 1 to 6 carbon atoms and 6 carbon atoms. 15 aryl group, an aralkyl group having 7 to 16 carbon atoms _{or, - (CH 2) n -COOR} 7 represents one of (n = Less than six integer) alkyl R ⁷ is from 1 to 6 carbon atoms Represents a group, an aryl group having 6 to 15 carbon atoms, or an aralkyl group having 7 to 16 carbon atoms. However,
At least one of R ^{4 to} R ⁶ represents an aryl group or an aralkyl group. Also, the alkyl groups listed above,
The aryl group and aralkyl group may be either unsubstituted or substituted, and can be selected according to the characteristics of the composition.

X in the general formula (3) represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a halogen element, or a cyano group. The alkyl group represented by X in the general formula (3) is preferably a methyl group, an ethyl group, an n-propyl group, an n-butyl group or a trifluoromethyl group. The halogen element represented by X in the general formula (3) is preferably iodine, bromine, chlorine or fluorine.

The alkyl group represented by R ^{4 to} R ⁶ in the general formula (3) is preferably methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, t-butyl group, trifluoro group. Methyl group, trichloromethyl group, 2,2,2
—Trifluoroethyl group, 2,2,2-trichloroethyl group, cyclohexyl group. The aryl group represented by R ^{4 to} R ⁶ in the general formula (3) is preferably a phenyl group, a tolyl group, a xylyl group, a chlorophenyl group, a hydroxyphenyl group, a dihydroxyphenyl group, a methoxyphenyl group, t-butoxycarbonyloxy. Phenyl group,
Examples thereof include a tetrahydropyranyloxyphenyl group and a naphthyl group. The aralkyl group represented by R ^{4 to} R ⁶ in the general formula (3) is preferably a benzyl group or a phenethyl group.

Represented by R ^{4 to} R ⁶ in the general formula (3),-(C
R ⁷ in H ₂ ) _n —COOR ⁷ (n = 0 to 6) is preferably a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a t-butyl group, a trifluoromethyl group, Trichloromethyl group, 2,2,2-trifluoroethyl group, 2,2,2-trichloroethyl group, cyclohexyl group, tetrahydropyranyl group, phenyl group,
Examples thereof include a tolyl group, a xylyl group, a chlorophenyl group, a hydroxyphenyl group, a dihydroxyphenyl group, a methoxyphenyl group, a t-butoxycarbonyloxyphenyl group, a tetrahydropyranyloxyphenyl group, a naphthyl group, a benzyl group and a phenethyl group.

Specific examples of the monomer for obtaining the polymer containing the structural unit represented by the general formula (3) are:
-Methyl-1-phenylethyl (meth) acrylate,
1-methyl-1-phenylethyl-α-trifluoromethyl acrylate, 1-methyl-1-phenylethyl-
α-chloroacrylate, 1-methyl-1-phenylethyl-α-bromoacrylate, 1-methyl-1-phenylethyl-α-cyanoacrylate, 1-methyl-1
-(P-Methyl) phenylethyl (meth) acrylate, 1-methyl-1- (p-chloro) phenylethyl (meth) acrylate, 1-methyl-1- (p-methoxy) phenylethyl (meth) acrylate, 1 -Methyl-1- (p-hydroxy) phenylethyl (meth) acrylate, 1-methyl-1- (p-tetrahydropyranyloxy) phenylethyl (meth) acrylate, 1-
Methyl-1-naphthylethyl (meth) acrylate, 1
-Methyl-1-phenylpropyl (meth) acrylate, 1-trifluoromethyl-1-phenylethyl (meth) acrylate, 1,1-dimethyl-2-phenylethyl (meth) acrylate, 1,1-dimethyl-2- Phenylethyl-α-bromoacrylate, 1,1-diphenylethyl (meth) acrylate, 1,1-diphenylethyl-α-chloroacrylate, 1-phenyl-1
-(P-methyl) phenyl (meth) acrylate, 1-
(Phenylmethyl) -1-phenylethyl (meth) acrylate triphenylmethyl (meth) acrylate,
Examples include 1,1,2-triphenylethyl (meth) acrylate and 1- (t-butoxycarbonylmethyl) -1-phenylethyl (meth) acrylate.

The copolymerization ratio of the structural unit represented by the general formula (3) in the polymer is not particularly limited, but is preferably 20 mol% to 99 mol%, more preferably 30 mol% to 90 mol%. Mol%.

The polymer of the present invention may be a polymer containing only the structural unit represented by the general formula (3), but may contain other monomer units as long as the characteristics as a chemically amplified resist are not impaired. You may stay.

Other monomer units include (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, (meth)
N-butyl acrylate, t-butyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2- (p-hydroxyphenyl) ethyl (meth) acrylate, β-methacryloyloxy-γ-butyrolactone, β-methacryloyloxy-β-methyl-γ-butyrolactone, α-
Methacryloyloxy-γ-butyrolactone, α-methyl chloroacrylate, α-ethyl chloroacrylate, α
-T-butyl chloroacrylate, methyl α-cyanoacrylate, ethyl α-cyanoacrylate, t-butyl α-cyanoacrylate, styrene, p-hydroxystyrene, p-acetoxystyrene, α-methylstyrene, α
-Methyl-p-hydroxystyrene, α-methyl-p-
Examples thereof include acetoxystyrene, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, vinylaniline, vinylpyrrolidone, and vinylimidazole.

The weight average molecular weight (M
w) is 300 in terms of polystyrene measured by GPC
It is 0 to 100,000, preferably 4000 to 50,000. If the Mw is less than the above range, the coating properties will deteriorate,
On the other hand, if the amount is larger than the above range, the solubility in the developing solution becomes poor.

The positive-working radiation-sensitive composition of the present invention contains an acid generator which generates an acid upon irradiation with radiation.
Specific examples of the acid generator include onium salts, halogen-containing compounds, diazoketone compounds, diazomethane compounds, sulfone compounds, sulfonic acid ester compounds, sulfonimide compounds and the like.

Specific examples of onium salts include diazonium salts, ammonium salts, iodonium salts, sulfonium salts, phosphonium salts, oxonium salts and the like.
Preferred onium salts include diphenyliodonium triflate, diphenyliodonium pyrene sulfonate, diphenyliodonium dodecylbenzene sulfonate, triphenylsulfonium triflate, triphenylsulfonium hexafluoroantimonate,
Triphenylsulfonium naphthalene sulfonate,
(Hydroxyphenyl) benzyl methyl sulfonium toluene sulfonate etc. are mentioned.

Specific examples of the halogen-containing compound include haloalkyl group-containing hydrocarbon compounds and haloalkyl group-containing heterocyclic compounds. Preferred halogen-containing compounds include 1,1-bis (4-chlorophenyl) -2,2,2-trichloroethane and 2-phenyl-
4,6-bis (trichloromethyl) -s-triazine,
2-naphthyl-4,6-bis (trichloromethyl) -s
-Triazine and the like.

Specific examples of the diazoketone compound include:
1,3-diketo-2-diazo compounds, diazobenzoquinone compounds, diazonaphthoquinone compounds and the like can be mentioned.
A preferred diazoketone compound is an ester of 1,2-naphthoquinonediazide-4-sulfonic acid and 2,2,3,4,4'-tetrahydroxybenzophenone, 1,2-
Naphthoquinonediazide-4-sulfonic acid and 1,1,1-
Examples thereof include esters with tris (4-hydroxyphenyl) ethane.

Specific examples of the diazomethane compound include bis (trifluoromethylsulfonyl) diazomethane, bis (cyclohexylsulfonyl) diazomethane, bis (phenylsulfonyl) diazomethane, bis (p-tolylsulfonyl) diazomethane, bis (2,4-quinone). Silylsulfonyl) diazomethane, bis (p-chlorophenylsulfonyl) diazomethane, methylsulfonyl-p-toluenesulfonyldiazomethane, cyclohexylsulfonyl (1,1-dimethylethylsulfonyl) diazomethane, bis (1,1-dimethylethylsulfonyl) diazomethane, phenylsulfonyl (Benzoyl) diazomethane and the like.

Specific examples of sulfone compounds include β-ketosulfone compounds and β-sulfonylsulfone compounds. Examples of preferable sulfone compounds include 4-trisphenacylsulfone, mesitylphenacylsulfone, bis (phenylsulfonyl) methane and the like.

Specific examples of the sulfonate compound include alkyl sulfonate, haloalkyl sulfonate, aryl sulfonate, imino sulfonate and the like. Preferred sulfonic acid ester compounds include benzoin tosylate, pyrogallol trimesylate, nitrobenzyl-9,10-diethoxyanthracene-2-sulfonate and the like.

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- ( Trifluoromethylsulfonyloxy) bicyclo [2.2.1] heptane-5,6-oxy-2,3-dicarboxylimide, N- (trifluoromethylsulfonyloxy) naphthyldicarboxylimide, 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) bicyclo [2.2.1] heptane-5,6-oxy-2,3-dicarboximide, N- (camphorsulfonyloxy) naphthyldicarboximide, N-
(4-methylphenylsulfonyloxy) succinimide, N- (4-methylphenylsulfonyloxy) phthalimide, N- (4-methylphenylsulfonyloxy) diphenylmaleimide, N- (4-methylphenylsulfonyloxy) bicyclo [2.2 .1] hept-5
-Ene-2,3-dicarboxylimide, N- (4-methylphenylsulfonyloxy) -7-oxabicyclo [2.2.1] hept-5-ene-2,3-dicarboxylimide, N- ( 4-Methylphenylsulfonyloxy) bicyclo [2.2.1] heptane-5,6-oxy-2,3-dicarboxylimide, N- (4-methylphenylsulfonyloxy) naphthyldicarboxylimide, N- (2 -Trifluoromethylphenylsulfonyloxy) succinimide, N- (2-trifluoromethylphenylsulfonyloxy) phthalimide, N- (2
-Trifluoromethylphenylsulfonyloxy) diphenylmaleimide, N- (2-trifluoromethylphenylsulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboxylimide, N- (2
-Trifluoromethylphenylsulfonyloxy) -7
-Oxabicyclo [2.2.1] hept-5-ene-
2,3-dicarboxylimide, N- (2-trifluoromethylphenylsulfonyloxy) bicyclo [2.
2.1] Heptane-5,6-oxy-2,3-dicarboximide, N- (2-trifluoromethylphenylsulfonyloxy) naphthyldicarboxylimide, N-
(4-Fluorophenylsulfonyloxy) succinimide, N- (2-fluorophenylsulfonyloxy)
Phthalimide, N- (4-fluorophenylsulfonyloxy) diphenylmaleimide, N- (4-fluorophenylsulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboxylimide, N-
(4-Fluorophenylsulfonyloxy) -7-oxabicyclo [2.2.1] hept-5-ene-2,3-
Dicarboxylimide, N- (4-fluorophenylsulfonyloxy) bicyclo [2.2.1] heptane-
5,6-oxy-2,3-dicarboxylimide, N-
(4-Fluorophenylsulfonyloxy) naphthyldicarboxylimide and the like can be mentioned.

These acid generators can be used alone or in admixture of two or more. The amount of the acid generator added is usually 0.01 to 50% by weight, more preferably 0.5 to 30% by weight, based on the polymer. If the amount is less than 0.01% by weight, pattern formation becomes impossible, and if the amount is more than 50% by weight, the affinity with the developing solution is lowered and defective development occurs.

If necessary, a dissolution accelerator, a dissolution inhibitor, a surfactant, a sensitizer, a stabilizer, a defoaming agent, an acid diffusion inhibitor, etc. may be added to the positive-working radiation-sensitive composition of the present invention. Agents can also be added.

The positive-type radiation-sensitive composition of the present invention can be obtained by dissolving the above components in a solvent. The amount of the solvent used is not particularly limited, but is adjusted so that the solid content is 5 to 30% by weight. As the solvent preferably used, ethyl acetate, butyl acetate, amyl acetate, ethyl propionate, methyl butyrate, methyl benzoate, methyl lactate, ethyl lactate, ethyl pyruvate, methyl β-isobutyrate, methyl 3-methoxypropionate, and 3 are used. -Ethyl ethoxypropionate, esters such as γ-butyrolactone, cellosolves such as methyl cellosolve, ethyl cellosolve and butyl cellosolve, cellosolve esters such as methyl cellosolve acetate, ethyl cellosolve acetate and butyl cellosolve acetate, propylene glycol monomethyl ether acetate, propylene glycol Propylene glycol esters such as monoethyl ether acetate, 1,2-dimethoxyethane, 1,2
-Ethers such as diethoxyethane, tetrahydrofuran, 1,4-dioxane, anisole, methyl ethyl ketone, methyl isobutyl ketone, 2-heptanone, 5
-Ketones such as methyl-3-heptanone, methyl-n-amyl ketone, cyclohexanone and isophorone, N
-Methylpyrrolidone, dimethyl sulfoxide, a solvent selected from aprotic polar solvents such as sulfolane, or a composite solvent of these.

The positive-working radiation-sensitive composition of the present invention is applied onto a substrate to be processed and dried, and usually used as a thin film having a thickness of 0.2 μm to 2 μm. A fine pattern can be obtained by subjecting this thin film to pattern exposure using radiation such as ultraviolet rays, far ultraviolet rays, vacuum ultraviolet rays, electron beams, and X-rays, and developing. In particular, the effect is great in the case of pattern exposure using an electron beam or X-ray, and the effect is more remarkable in the case of using an electron beam.

Development of the positive-working radiation-sensitive composition of the present invention can be carried out using a known developer. As specific examples, hydroxides, carbonates, phosphates of alkali metals,
Inorganic alkalis such as silicates and borates, amines such as 2-diethylaminoethanol, monoethanolamine and diethanolamine, and aqueous solutions containing one or more quaternary ammonium such as tetramethylammonium hydroxide and choline. Can be mentioned.

[0047]

The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. The weight average molecular weight (Mw) of the obtained polymer
Is a value calculated in terms of polystyrene using GPC.

Example 1 In a flask under a nitrogen atmosphere, 1,1-diphenylethyl methacrylate (50 mmol) and α- were used as monomers.
Methacryloyloxy-γ-butyrolactone (50 mm
2) -azobis (isobutyric acid) dimethyl (5 mmol) as a polymerization initiator and 2- (diethylamino) ethanethiol (20 mmo as a chain transfer agent).
l) and 1,4-dioxane (100 ml) as a solvent were added, and the mixture was heated and stirred at 70 ° C. for 10 hours to carry out polymerization.
The obtained polymerization solution was dropped into a large amount of hexane with stirring to precipitate the polymer. The precipitate obtained is filtered off,
It was dried under reduced pressure for 10 hours to obtain a polymer (A-1) represented by the following chemical formula. The weight average molecular weight of the obtained polymer was 10,000, and the copolymerization composition ratio was m / n = 50/50 m.
It was ol%.

[0049]

[Chemical 7]

Example 2 1,1-Diphenylethyl-α-chloroacrylate (50 mmol) and α-methacryloyloxy-γ-butyrolactone (50 mmol) were charged as monomers, and 4-mercaptopiperidine (20 mmo) was added as a chain transfer agent.
Synthesis was performed in the same manner as in Example 1 except that the procedure was changed to l).
A polymer (A-2) represented by the following chemical formula was obtained. The weight average molecular weight of the obtained polymer was 8000, and the copolymerization composition ratio was m / n = 48/52 mol%.

[0051]

[Chemical 8]

Example 3 Monomer was charged as 1,1-diphenylethyl-α-cyanoacrylate (50 mmol) and α-methacryloyloxy-γ-butyrolactone (50 mmol), and a chain transfer agent was added as thioglycolamide (20 mmo).
Synthesis was performed in the same manner as in Example 1 except that the procedure was changed to l).
A polymer (A-3) represented by the following chemical formula was obtained. The weight average molecular weight of the obtained polymer was 9000, and the copolymerization composition ratio was m / n = 49/51 mol%.

[0053]

[Chemical 9]

Example 4 1- (Phenylmethyl) -1-phenylethylmethacrylate (50 mmol) and α-methacryloyloxy-γ-butyrolactone (50 mmo) were charged as monomers.
l), except that the addition of the chain transfer agent was changed to 2,2′-dithiodianiline (20 mmol), the synthesis was carried out in the same manner as in Example 1, and the polymer (A-4) represented by the following chemical formula:
Got The weight average molecular weight of the obtained polymer was 750.
0, the copolymer composition ratio was m / n = 45/55 mol%.

[0055]

[Chemical 10]

Example 5 Monomer was charged to prepare 1- (t-butoxycarbonylmethyl) -1-phenylethyl acrylate (50 mmo).
l) and α-methacryloyloxy-γ-butyrolactone (50 mmol), except that the addition of the chain transfer agent was changed to 2,2′-dithiodibenzoic acid dimethylamide (20 mmol), synthesis was performed in the same manner as in Example 1, A polymer (A-5) represented by the following chemical formula was obtained. The weight average molecular weight of the obtained polymer was 8500, and the copolymerization composition ratio was m / n =
It was 48/52 mol%.

[0057]

[Chemical 11]

Example 6 Synthesis was conducted in the same manner as in Example 1 except that the charge of monomers was changed to 2-methacryloyloxy-2-methyladamantane (50 mmol) and α-methacryloyloxy-γ-butyrolactone (50 mmol). A polymer (A-6) represented by the following chemical formula was obtained. The weight average molecular weight of the obtained polymer was 10500, and the copolymer composition ratio was m /
It was n = 48/52 mol%.

[0059]

[Chemical 12]

Comparative Example 1 Example 1 except that the addition of the chain transfer agent was changed to no addition.
Synthesis was performed in the same manner as in, to obtain a polymer (A-7) represented by the following chemical formula. The weight average molecular weight of the obtained polymer was 35,000, and the copolymerization composition ratio was m / n = 50 / 50mo.
It was 1%.

[0061]

[Chemical 13]

Comparative Example 2 A chain transfer agent was added to cyclohexanethiol (20 mm
was carried out in the same manner as in Example 1, except that the polymer (A-8) represented by the following chemical formula was obtained.
The weight average molecular weight of the obtained polymer was 9500, and the copolymerization composition ratio was m / n = 50/50 mol%.

[0063]

[Chemical 14]

Examples 7 to 13 and Comparative Examples 3 to 6 Each polymer (10 g) of A-1 to A-8 was treated with triphenylsulfonium triflate (1.5 g) as an acid generator.
g) and propylene glycol monomethyl ether acetate (103.5 g) as a solvent were added to form a uniform solution, which was then filtered through a filter having a pore size of 0.1 μm to prepare a resist composition. Then, each resist composition was spin-coated on a silicon wafer, and then prebaked at 130 ° C. for 1 minute using a hot plate to form a resist film having a film thickness of 0.4 μm. Each of these resist films is exposed in a pattern by using an electron beam exposure device (accelerating voltage 20 kV) or a KrF excimer laser stepper, and then exposed and baked at 90 ° C. for 2 minutes using a hot plate, and tetramethylammonium is used. Development was carried out with an aqueous hydroxide solution. Table 1 shows the evaluation results of the obtained resist patterns.

[0065]

[Table 1]

Example 13 and Comparative Example 6 were exposed with a KrF excimer laser stepper. Other than that was exposed by an electron beam exposure apparatus (accelerating voltage 20 kV). In Comparative Example 5, triethylamine (0.01 g) was added as an additive to prepare a resist composition.

[0067]

By using the resist polymer obtained by the production method of the present invention, it is possible to obtain a positive radiation-sensitive composition having high sensitivity, high resolution and being hardly affected by the environment.

Continued front page    F term (reference) 2H025 AA01 AA02 AB16 AC04 AC05                       AC06 AD03 BE00 BG00 BJ10                       FA03 FA12 FA17                 4J011 HA04 NA24 NA25 NB04 NB06                 4J100 AL08P AL08Q AL26P BA02P                       BA03P BA05P BA11Q BA20P                       BA40P BB01P BB03P BB18P                       BC43P BC49P BC53P BC53Q                       CA01 CA03 DA01 FA03 FA04                       FA19 HA08 JA38

Claims (5)

[Claims] 1. A method for producing a resist polymer, which comprises polymerizing a monomer by adding a chain transfer agent containing at least one nitrogen atom. 2. A chain transfer agent is represented by the general formula (1) or the general formula (2).
The method for producing a resist polymer according to claim 1, wherein the compound is at least one of the compounds represented by: [Chemical 1] (In the formula, R ¹ represents an organic group containing at least one nitrogen atom.) (In the formula, R ² and R ³ represent an organic group containing at least one nitrogen atom, and R ² and R ³ may be the same or different from each other.) (A) A polymer produced by the method according to claim 1 or 2, which is alkali-soluble by the action of an acid,
And (b) a positive radiation-sensitive composition containing an acid generator that generates an acid upon irradiation with radiation. 4. The positive radiation-sensitive composition according to claim 3, wherein (a) is a polymer containing a structural unit represented by the general formula (3). [Chemical 3] (In the formula, X is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms,
Represents either a halogen element or a cyano group, R ⁴
To R ⁶ may be the same or different and each is an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 15 carbon atoms, an aralkyl group having 7 to 16 carbon atoms, or — (CH ₂ ) _n —
Represents any of COOR ⁷ (n = 0 to 6), R ⁷
Represents an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 15 carbon atoms, or an aralkyl group having 7 to 16 carbon atoms. However, at least one of R ^{4 to} R ⁶ represents an aryl group or an aralkyl group. ) 5. The positive-working radiation-sensitive composition according to claim 3, wherein the radiation to be applied is an electron beam or an X-ray.