JP2000336119A - Production of acetal compound of polyvinylphenol and radiation-sensitive composition produced by using the compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for stably producing an acetalized polyvinylphenol at a prescribed protection ratio and provide a radiation-sensitive composition having small lot-to-lot variation of the performance. SOLUTION: This process for the production of acetalized polyvinylphenol comprises the reaction of (A) a polyvinylphenol with (B) a compound having a C=C-O partial structure and capable of forming an acetal structure by the reaction with the polyvinylphenol A in the presence of an organic solvent to acetalize at least a part of the phenolic hydroxyl group of the polyvinylphenol. In the above process, the reaction is carried out by preparatorily mixing the compound B with the organic solvent and then mixing with the polyvinylphenol.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an acetal compound of polyvinyl phenols and a radiation-sensitive composition using the same, and more particularly, to a photoresist material for producing a semiconductor integrated circuit. Hereinafter, the present invention relates to a method for producing an acetal compound suitable as "resist" and a radiation-sensitive composition using the same.

[0002]

2. Description of the Related Art High integration of a semiconductor integrated circuit progresses four times in three years as generally known, for example, a dynamic random access memory (DR).
AM) as an example, full-scale production of a memory having a storage capacity of 64 Mbits has now started. Accordingly, the demand for photolithography technology, which is indispensable for the production of integrated circuits, is increasing year by year. For example, the production of a 64 Mbit DRAM requires a lithography technology of a 0.30 μm level, and a 256 M DRAM with a higher degree of integration requires a lithography technology of a 0.20 μm level. Along with this, development of a resist that can correspond to each lithography level has been eagerly desired.

[0003] In today's ultra-fine process, the wavelength used for resist exposure is also the i-line (365 nm) of a mercury lamp.
The wavelength has been reduced to KrF excimer laser light (248 nm), and various chemically amplified positive photoresists have been proposed as positive resists suitable for such short wavelength exposure. (Japanese Patent Publication No. 27660/1994,
3-27829). The chemically amplified resist controls the solubility of a radiation-irradiated portion in a developing solution by a catalytic action of an acid generated by irradiation of radiation (ultraviolet rays, far-ultraviolet rays, X-rays, charged particle beams such as electron beams, etc.). It is a resist and contains a compound whose solubility in an alkali developing solution is increased by an acid catalyzed reaction with an acid generator.

As a resin used in such a chemically amplified resist composition, for example, a resin having a functional group exhibiting alkali solubility such as a phenolic hydroxyl group, such as polyvinylphenols (hereinafter simply referred to as a “base resin”). ) Is protected by a protecting group capable of being eliminated by an acid catalyst (hereinafter, may be simply referred to as a "protecting group"). Those whose solubility in an alkali developing solution is increased by the catalytic action of the generated acid are often used. Many of these protecting groups have been studied in the past, and among them, many groups particularly containing an acetal structure have been reported.

[0005]

By the way, when an acid-eliminable protecting group having such an acetal structure (hereinafter sometimes simply referred to as "acetal protecting group") is introduced into a base resin, a general method is used. Has an unprotected base resin,
In general, a method of reacting a compound such as an alkyl vinyl ether capable of forming an acetal structure by reacting with the compound (hereinafter, may be simply referred to as an “acetalizing agent”) in a solution under an acid catalyst is generally used. Has been adopted. However, it has been found that the acetalizing agent used in this reaction generally has a low boiling point, so that it is likely to volatilize and dissipate during the production and the actual reaction amount tends to be unstable. This means that the introduction rate of the acetal protecting group differs depending on the production lot, and as a result, the variation in the resist performance of the radiation-sensitive composition using such an acetalized compound varies from lot to lot. This means that there is a problem that the system is not stable. An object of the present invention is to improve the method for introducing an acetal protecting group, reduce the variation in the introduction ratio between lots, and thereby to stabilize the quality of the radiation-sensitive composition.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, when stably producing an acetalized product, the acetalizing agent was previously diluted with a solvent and used in the reaction. By doing so, we found that we could solve this problem. That is, the present invention relates to polyvinyl phenols (A) and> C = C—O—
(B) having a partial structure of (A) and capable of forming an acetal structure by reaction with a polyvinylphenol (A)
Is reacted in the presence of an organic solvent to produce a compound in which at least a part of the phenolic hydroxyl group of the polyvinylphenol is acetalized. The compound (B) is previously mixed with an organic solvent, and then the polyvinylphenol is mixed. The present invention relates to a method for producing an acetalized product of a polyvinyl phenol, which is characterized by being mixed with and reacting with an alcohol. Another aspect relates to a radiation-sensitive composition containing the acetal compound obtained by the above method and a radiation-sensitive compound which generates an acid by the action of radiation.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
In the present invention, the compound (B) having a partial structure of> C ＝ C—O— and capable of forming an acetal structure by reacting with the polyvinylphenols (A) is defined as a phenolic hydroxyl group of the polyvinylphenols. Is not particularly limited as long as it is a compound capable of forming an acetal structure “—O—C—O—” by reaction with an alkyl group and a vinyl group. Examples thereof include alkyl vinyl ethers which may have an arbitrary substituent, and more specifically, the following compound (B ') which can form an acetal structure by the following reaction.

[0008]

Embedded image

(In the formula (B '), R¹Is replaced
Represents an alkyl group which may be substituted. Also, R ^Two~ R^FourIndependently
Indicates a hydrogen atom or an optionally substituted alkyl group
You. R¹Is R^ThreeOr R^FourAnd forming a ring
good. ) N represents the number of repeating units. R¹A shown by
The number of carbon atoms in the alkyl group is sensitive to the resulting acetal compound.
1 to 20 or more in terms of performance when used as a hydrophobic composition
The lower part is preferable, and the number is more preferably 1 to 10 in particular.
R^Two~ R^FourThe alkyl group represented by the formula has 1 to 6 carbon atoms.
The following are preferable, and especially 1 or more and 4 or less are preferable. Also R^Two
~ R^FourIs preferably a hydrogen atom.

The compound (B ') shown here, that is, as an acetalizing agent, specifically, methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, iso-propyl vinyl ether, n-butyl vinyl ether, tert-butyl vinyl ether , Cyclohexyl vinyl ether, dihydropyran and the like. Among these acetalizing agents, when the boiling point at room temperature is 150 ° C. or lower, the disadvantage that the acetalizing agent volatilizes and disperses particularly during the production and the amount of the actually reacted becomes unstable can be suppressed, which is more preferable.

The polyvinylphenols (A) of the present invention are polyvinylphenols or derivatives thereof. Examples of the derivative of polyvinylphenol include a homopolymer of hydroxystyrene having a substituent or a resin obtained by copolymerizing with various vinyl monomers. Vinyl monomer copolymerized with hydroxystyrene
For example, styrene, acrylic acid, vinyl alcohol or derivatives thereof are used.

As the polyvinylphenols, specifically, o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, 2- (o-hydroxyphenyl) propylene, 2- (m-hydroxyphenyl)
A resin obtained by polymerizing one or more hydroxystyrenes such as propylene and 2- (p-hydroxyphenyl) propylene in the presence of a radical polymerization initiator, an anionic polymerization initiator or a cationic polymerization initiator is used. Further, a resin which has been subjected to hydrogenation in order to reduce the absorbance of the resin after polymerization may be used, or a halogen atom, a nitro group, an ester group, or the like in the aromatic compound monomer as long as it does not adversely affect the present invention. It may have a substituent.

The hydroxy aromatic compound may have a substituent such as a halogen atom, a nitro group, an ester group and the like as long as the compound does not adversely affect the present invention. If necessary, these resins may be further reduced with hydrogen or the like to reduce the absorbance in the short wavelength region. As these polyvinylphenols, preferably, poly (p
-Hydroxystyrene) is used.

The weight average molecular weight of the above-mentioned polyvinyl phenols is generally from 1,000 to 100,000, preferably from 2,000 to 60,000 in terms of polystyrene (measured by gel permeation chromatography).
000 or less, more preferably 2,000 or more and 30,0
00 or less is used. If the molecular weight is smaller than this range, a sufficient coating film as a resist cannot be obtained, and the heat resistance may be deteriorated. On the other hand, if it is larger than this range, the solubility of the exposed portion in the alkali developing solution becomes small, and the pattern after resist exposure may not be obtained.

Further, when the molecular weight distribution (Mw / Mn) of polyvinyl phenols is wide, a low molecular weight or high molecular weight polymer is present, and when a large amount of low molecular weight polymer is present, heat resistance may be reduced, and high molecular weight Including those that are difficult to dissolve in alkali when there are many polymers of
This may cause footing after pattern formation. Therefore, as the pattern rule becomes finer, the influence of such molecular weight and molecular weight distribution tends to increase. Therefore, in order to obtain a resist material suitably used for fine pattern dimensions, the molecular weight distribution of the base resin must be as follows. It is preferably a narrow dispersion of 0 to 1.5, particularly 1.0 to 1.3.

When the above-mentioned polyvinyl phenols are reacted with an acetalizing agent, the polyvinyl phenols are usually dissolved in a solvent, and an acid catalyst and an acetalizing agent are mixed therein, and the reaction is carried out. At this time, it is characterized in that the acetalizing agent is mixed with polyvinylphenols in a state of being dissolved in a solvent. Here, the solvent for dissolving the acetalizing agent is not particularly limited as long as it has practical solubility in the acetalizing agent and does not inhibit the reaction. The solvent may be the same as or different from the solvent in which it is dissolved, but is preferably the same in the production process.

Specific examples of the solvent include diethyl ether, tetrahydrofuran, 1,3-dioxolan,
Ethers such as 4-dioxane, acetone, ketones such as methyl isobutyl ketone, ethyl acetate, esters such as n-butyl acetate, nitriles such as acetonitrile, sulfoxides such as dimethyl sulfoxide, benzene, And aromatic hydrocarbons such as toluene. Among them, ethers, particularly 1,3-dioxolane, are preferred from the viewpoint of solubility and ease of handling during the reaction. These solvents may be used alone or as a mixture of two or more.

The concentration of the acetalizing agent when diluted with an organic solvent is usually 10% to 90%, preferably 20% to 80%, more preferably 20% to 70% by weight.
It is. If the concentration is lower than this range, no special effect is obtained, and a large amount of solvent is required, and there is no advantage in the production process. If it is higher than this range, there is a fear that the effect of preventing dissipation by dilution with the solvent may not be sufficiently obtained. In reacting the polyvinyl phenols and the acetalizing agent, with respect to the molar equivalent of the phenolic hydroxyl group in the polyvinyl phenols,
The amount to be added is determined based on the number of moles of the acetalizing agent necessary to obtain a desired introduction ratio of the protecting group. When water is contained in the solvent used for the reaction and the raw material such as polyvinylphenol, the water content may be determined in consideration of the water content. From the viewpoint of heat resistance and image forming ability, the introduction rate of the protecting group is usually 5 to 5 for the phenolic hydroxyl group.
60% is appropriate, and a more preferable introduction rate is 10%.
-60%, more preferably 20-50%. The protecting group is eliminated by the action of an acid generated from a photoacid generator described below, and contributes to improving the solubility of the radiation-sensitive composition in a developer.

The reaction temperature between the polyvinyl phenol and the acetalizing agent is not particularly limited as long as the solution is kept in a liquid state. However, from the viewpoint of the reaction rate and the volatilization of the solvent and the acetalizing agent, the reaction temperature is 100 ° C. or more. ° C or lower, preferably 10 ° C or higher and 70 ° C or lower, more preferably 20 ° C or higher and 5 ° C or lower.
0 ° C. or less. The reaction time is usually 0.5 hours or more and 48 hours or less. From the viewpoint of the reaction yield and productivity, the reaction time is 1 hour or more and 24 hours or less, and more preferably 1 hour or more and 12 hours or less.
It is preferably less than or equal to the time.

In this reaction, an acid catalyst is usually used. The acid catalyst is not particularly limited as long as it has sufficient acidity to cause an acetalization reaction, and specifically, hydrochloric acid,
Mineral acids such as sulfuric acid, nitric acid, carboxylic acids such as formic acid, acetic acid, butyric acid, methanesulfonic acid, benzenesulfonic acid,
Examples thereof include sulfonic acids such as toluenesulfonic acid, and phosphonic acids such as methanephosphonic acid and benzenephosphonic acid. Of these, mineral acids, especially hydrochloric acid, are preferred. These acids may be used alone or as a mixture of two or more. In addition, it may be added as it is, or may be added in a state diluted in a solvent or in a slurry state. These acids are added in an amount of 0.00001 mol or more and 1 mol or less, preferably 0.0001 mol or more and 0.1 mol or less, more preferably 0.001 mol or more and 0 mol or less, relative to 1 mol equivalent of the phenolic hydroxyl group. 0.05 mol or less. If the amount of the acid is less than this range, the reaction rate becomes insufficient, and the production efficiency may be reduced. On the other hand, if it is larger than this range, a large amount of a basic compound is required in the subsequent neutralization step, and the generated salt tends to be mixed into the acetalized product, making it difficult to remove it.

In the present reaction, the above-mentioned acid catalyst needs to be removed by neutralizing the reaction solution after completion of the reaction. The neutralization is not particularly limited as long as it is a basic compound. Specifically, metal hydroxides such as sodium hydroxide and potassium hydroxide, ammonia water and ammonia gas, methylamine, ethylamine Amines such as dimethylamine, diethylamine, trimethylamine and triethylamine, pyridines such as pyridine, methylpyridine, aminopyridine, (N, N-dimitylamino) pyridine (DMAP), and quaternary such as tetraalkylammonium hydroxide Ammonium compounds and the like. Among these, ammonia water, nitrogen-containing basic compounds such as amines and pyridines are preferable. These basic compounds may be used alone,
More than one species may be used in combination. In addition, it may be added as it is, or may be added in a state diluted in a solvent or in a slurry state. These basic compounds are added to the reaction solution after the completion of the reaction.
It is preferable that the number be 14 or less, more preferably 8 or more and 12 or less. If the pH value is lower than this range, the neutralization becomes insufficient and the decomposition of the acetalized product may occur. If the pH value is higher than this range, it becomes difficult to remove the basic compound from the acetalized product, which is not preferable. The acetalized product thus obtained is isolated and purified by a known method such as reprecipitation from a solution, and is suitably used for a radiation-sensitive composition.

In using the acetalized product produced by the present invention in a radiation-sensitive composition, the acetalized product is used together with a radiation-sensitive compound capable of generating an acid by the action of radiation (hereinafter, referred to as a photoacid generator). The photoacid generator used in the present invention is not particularly limited as long as it generates an acid by actinic rays or radiation used for exposure, and conventionally known ones can be used. For example, tris (trichloromethyl) -s-triazine, tris (tribromomethyl)-
s-triazine, tris (dibromomethyl) -s-triazine, 2,4-bis (tribromomethyl) -6-p-
Halogen-containing s-triazine derivatives such as methoxyphenyl-s-triazine, halogen-substituted paraffins such as 1,2,3,4-tetrabromobutane, 1,1,2,2-tetrabromoethane, carbon tetrabromide and iodoform -Based hydrocarbons, halogen-substituted cycloparaffin-based hydrocarbons such as hexabromocyclohexane, hexachlorocyclohexane, and hexabromocyclododecane; halogen-containing benzene derivatives such as bis (trichloromethyl) benzene and bis (tribromomethyl) benzene; tribromomethylphenyl Halogen-containing sulfone compounds such as sulfone, trichloromethylphenylsulfone, and 2,3-dibromosulfolane; halogen-containing isocyanurate derivatives such as tris (2,3-dibromopropyl) isocyanurate; Sulfonium such as sulfonium chloride, triphenylsulfonium methanesulfonate, triphenylsulfonium trifluoromethylsulfonate, triphenylsulfonium, p-toluenesulfonate, triphenylsulfonium tetrafluoroborate, triphenylsulfonium hexafluoroarsenate, triphenylsulfonium hexafluorophosphonate Iodonium salts such as salts, diphenyliodonium trifluoromethylsulfonate, diphenyliodonium p-toluenesulfonate, diphenyliodonium tetrafluoroborate, diphenyliodonium hexafluoroarsenate, diphenyliodonium hexafluorophosphonate, methyl p-toluenesulfonate, p-toluenesulfonate Ethyl acid, butyl p-toluenesulfonate, phenyl p-toluenesulfonate, 1,2,3-tri (p-toluenesulfonyloxy) benzene, p-toluenesulfonic acid benzoin ester, methyl methanesulfonate, ethyl methanesulfonate Butyl methanesulfonate, 1,2,3-tri (methanesulfonyloxy) benzene, phenyl methanesulfonate, benzoin methanesulfonate, methyl trifluoromethanesulfonate, ethyl trifluoromethanesulfonate, butyl trifluoromethanesulfonate,
Sulfonates such as 1,2,3-tri (trifluoromethanesulfonyloxy) benzene, phenyl trifluoromethanesulfonate and benzoin trifluoromethanesulfonate, disulfones such as diphenyldisulfone, and carbonyls such as phenylcarbonylphenylsulfonyldiazomethane Bissulfonylmethanes such as sulfonyldiazomethanes, bis (phenylsulfonyl) methane, bis (cyclohexylsulfonyl) methane, bis (phenylsulfonyl) diazomethane, bis (cyclohexylsulfonyl) diazomethane,
Bis-sulfonyldiazomethanes such as (cyclohexylsulfonyl) (4-methoxyphenylsulfonyl) diazomethane, (cyclohexylsulfonyl) (2-naphthylsulfonyl) diazomethane, o-nitrobenzyl-p
O-nitrobenzyl esters such as toluenesulfonate, sulfonhydrazides such as N, N'-di (phenylsulfonyl) hydrazide, iminosulfonates such as phthaliminotrifluoromethylsulfonate, phthalimino p-toluenesulfonate and phthaliminocamphorsulfonate And the like. Among these, compounds that generate sulfonic acid after exposure are preferably used, and bissulfonyldiazomethanes represented by the following general formula (I) are particularly preferable.

[0023]

Embedded image

(Q ¹ and Q ² independently represent a linear, branched or cyclic alkyl group which may be substituted, an aryl group which may be substituted, and an aralkyl group which may be substituted.)

In the radiation-sensitive composition of the present invention, the photoacid generator is used in an amount of 0.001 to 30 parts by weight, preferably 0.05 to 100 parts by weight, based on 100 parts by weight of the polyvinyl phenol (A).
Used in a proportion of 20 parts by weight. If the amount of the photoacid generator is less than this range, the sensitivity is inferior. If the amount is larger than this range, the transparency of the resist film due to the photoacid generator may cause the resist pattern to become trapezoidal, causing a reduction in resolution. is there.

Additives can be added to the radiation-sensitive composition of the present invention to such an extent that the effects of the present invention are not impaired. Examples of the additives include a dissolution inhibitor, an organic carboxylic acid, a surfactant, a dye, a sensitizer, and a nitrogen-containing compound. A dissolution inhibitor is a compound that controls the solubility of unexposed portions of polyvinylphenols (A) in an alkali developer.
A low molecular compound or a high molecular resin may be used as long as it has a group capable of leaving by acid catalysis. Preferred are compounds in which a hydrogen atom of an acidic functional group such as a phenolic hydroxyl group or a carboxyl group is protected by a group capable of leaving by an acid catalyst. Specifically, JP-A-9-62006 and JP-A-9-27
4320, JP-A-9-281697, JP-A-9-278
699, JP-A-9-50127, JP-A-9-23692
Compounds described in JP-A No. 1-No.

Further, the dissolution inhibitors used in the present invention can be used alone or in combination of two or more. When the dissolution inhibitor is added, it is used in an amount of 1 to 50 parts by weight, preferably 5 to 30 parts by weight, based on 100 parts by weight of the polyvinyl phenol (A). A nitrogen-containing compound is a compound that acts as a base to an acid, and during the period from exposure to post-exposure bake, the acid generated at the time of pre-bake or the acid generated from the acid generator at the time of exposure moves, and the resist pattern is dimensioned. This is effective to prevent fluctuations. Accordingly, the compound is not particularly limited as long as it can neutralize the acid generated from the acid generator as described above, and examples thereof include an organic amine compound. Specifically, for example, pyrimidine, 2-aminopyrimidine, 4-aminopyrimidine, 5-aminopyrimidine, 2,4-diaminopyrimidine, 2,5-diaminopyrimidine, 4,5-diaminopyrimidine, 4,6-diamino Pyrimidine, 2,
4,5-triaminopyrimidine, 2,4,6-triaminopyrimidine, 4,5,6-triaminopyrimidine,
2,4,5,6-tetraaminopyrimidine, 2-hydroxypyrimidine, 4-hydroxypyrimidine, 5-hydroxypyrimidine, 2,4-dihydroxypyrimidine,
2,5-dihydroxypyrimidine, 4,5-dihydroxypyrimidine, 4,6-dihydroxypyrimidine, 2,
4,5-trihydroxypyrimidine, 2,4,6-trihydroxypyrimidine, 4,5,6-trihydroxypyrimidine, 2,4,5,6-tetrahydroxypyrimidine, 2-amino-4-hydroxypyrimidine, -Amino-5-hydroxypyrimidine, 2-amino-4,5-
Dihydroxypyrimidine, 2-amino-4,6-dihydroxypyrimidine, 4-amino-2,5-dihydroxypyrimidine, 4-amino-2,6-dihydroxypyrimidine, 2-amino-4-methylpyrimidine, 2-amino-5 -Methylpyrimidine, 2-amino-4,5-dimethylpyrimidine, 2-amino-4,6-dimethylpyrimidine, 4-amino-2,5-dimethylpyrimidine, 4-amino-2,6-dimethylpyrimidine, 2- Amino-4-
Methoxypyrimidine, 2-amino-5-methoxypyrimidine, 2-amino-4,5-dimethoxypyrimidine, 2
-Amino-4,6-dimethoxypyrimidine, 4-amino-2,5-dimethoxypyrimidine, 4-amino-2,6
-Dimethoxypyrimidine, 2-hydroxy-4-methylpyrimidine, 2-hydroxy-5-methylpyrimidine,
2-hydroxy-4,5-dimethylpyrimidine, 2-hydroxy-4,6-dimethylpyrimidine, 4-hydroxy-2,5-dimethylpyrimidine, 4-hydroxy-
2,6-dimethylpyrimidine, 2-hydroxy-4-methoxypyrimidine, 2-hydroxy-4-methoxypyrimidine, 2-hydroxy-5-methoxypyrimidine,
Pyrimidine compounds such as -hydroxy-4,5-dimethoxypyrimidine, 2-hydroxy-4,6-dimethoxypyrimidine, 4-hydroxy-2,5-dimethoxypyrimidine, 4-hydroxy-2,6-dimethoxypyrimidine, pyridine, Pyridine compounds such as methylpyridine, N, N-dimethylaminopyridine, 2,6-dimethylpyridine, diethanolamine, triethanolamine, triisopropanolamine, tris (hydroxymethyl) aminomethane, bis (2-hydroxyethyl)
Amines substituted with a hydroxyalkyl group having 1 to 4 carbon atoms, such as iminotris (hydroxymethyl) methane, 2-aminophenol, 3-aminophenol,
Examples thereof include aminophenols such as 4-aminophenol, and pyridines and amines having a hydroxy group are preferred. The content of the nitrogen-containing compound is preferably from 0.1 to 100 mol%, more preferably from 1 to 50 mol%, based on the content of the photoacid generator.

The organic carboxylic acid is used for the purpose of suppressing a decrease in resist performance due to invasion of a basic substance from the environment. Specific examples of organic carboxylic acids include formic acid, acetic acid, propionic acid, n-butyric acid, iso-butyric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, acrylic acid, methacrylic acid, maleic acid, fumaric acid, and the like. Aliphatic carboxylic acids, ketocarboxylic acids such as pyruvic acid, benzoic acid, salicylic acid, m-hydroxybenzoic acid, p-hydroxybenzoic acid, 2,4-dihydroxybenzoic acid, 2,5
-Aromatic carboxylic acids such as dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid, phthalic acid, terephthalic acid, isophthalic acid, or SAX (trade name; manufactured by Mitsui Toatsu Chemicals)
A polymer containing a structural unit of an aromatic carboxylic acid which is commercially available as, for example, can be used. The organic carboxylic acid is added in an amount of 0.0001 to 10 parts by weight, preferably 0.1 to 100 parts by weight, based on 100 parts by weight of the polyvinyl phenol (A).
It is used in a ratio of 001 to 5 parts by weight.

Surfactants are added for the purpose of improving the coating properties of the radiation-sensitive resin composition, improving the uniformity of the film thickness during spin coating, and improving the developability of the radiation-sensitive resin composition. Is done. Surfactants that can be used for such purposes include, for example, polyoxyethylene lauryl ether,
Polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene nonyl phenyl ether, polyoxyethylene glycol laurate, polyoxyethylene glycol distearate, F-top EF301, EF303, EF352 (toe Manufactured by Chem Products Co., Ltd.), MegaFac F170, F17
1, F172, F173 (Dai Nippon Ink Co., Ltd.), Florade FC430, FC431, FC170C (Sumitomo 3M
Asahi Guard AG710, Surflon S-38
2, SC-101, SC-102, SC-103, SC
-104, SC-105, SC-106 (manufactured by Asahi Glass Co., Ltd.), KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.), Polyflow No.
75, no. 95 (manufactured by Kyoeisha Yushi Kagaku Kogyo) and the like.

These surfactants can be used alone or as a mixture of two or more kinds. Usually, 100 parts by weight of polyvinyl phenol (A) is added to surfactant 0.0%.
It is used in a proportion of 1 part by weight or more and 3 parts by weight or less. When an image of a resist is formed on a substrate having a high reflectance, such as aluminum, a light absorbing agent can be added to prevent deterioration of the resist pattern shape due to reflection of exposure light from the substrate. Examples of light absorbers used for such purposes include naphthoquinonediazide compounds, benzophenones,
Examples thereof include condensed aromatic ring-containing compounds such as naphthalene and anthracene.

The radiation-sensitive composition of the present invention comprises a polyvinyl phenol (A), a photoacid generator, a dissolution inhibitor,
It is used by dissolving it in an appropriate solvent capable of dissolving the above components such as a nitrogen-containing compound. Preferred solvents are 2-hexanone, ketone solvents such as cyclohexanone, cellosolve solvents such as methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, diethyl oxalate, ethyl pyruvate, ethyl-2-hydroxybutyrate, Ester solvents such as ethyl acetoacetate, butyl acetate, amyl acetate, ethyl butyrate, butyl butyrate, methyl lactate, ethyl lactate, methyl 3-methoxypropionate, and methyl 2-hydroxy-2-methylpropionate; propylene glycol monomethyl ether; Propylene glycol monoethyl ether, propylene glycol monobutyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate Propylene glycol solvents such as propylene glycol monobutyl ether acetate and dipropylene glycol dimethyl ether; ketone solvents such as cyclohexanone, methyl amyl ketone and 2-heptanone; or mixed solvents thereof, or further aromatic hydrocarbons were added. And the like. The proportion of the solvent used is desirably in the range of 1 to 20 times by weight based on the total amount of the solid content of the photosensitive composition.

In the case of forming a resist pattern on a semiconductor substrate using the radiation-sensitive composition of the present invention, usually,
The radiation-sensitive composition of the present invention dissolved in a solvent as described above is applied on a semiconductor substrate, and can be used as a photoresist through each step of pre-baking, pattern transfer by exposure, baking after exposure, and development. . The semiconductor substrate is
Usually, it is used as a substrate for semiconductor manufacturing, such as a silicon substrate or a gallium arsenide substrate. still,
If necessary, various known antireflection films can be used on the substrate and the resist film.

For example, see JP-A-6-148896 and JP-A-6-148896.
-118630, 6-148896, 5-24
No. 1332, US Pat. No. 5,688,987, 569,369
No. 1, No. 536889, No. 5234990, No. 5
The antireflection film described in No. 110697 can be used. A spin coater is usually used for coating, and light exposure of 157 nm, 193 nm, 222 nm, 248 nm or an electron beam using a light source of a low-pressure mercury lamp of 254 nm, excimer laser or the like is preferably used for exposure, and preferably 15 nm.
It is a deep UV of 0 to 300 nm, and it is particularly advantageous to use an excimer laser as a light source. The light at the time of exposure is
Instead of monochromatic light, it may be broad. Exposure by a phase shift method is also applicable.

Examples of the alkaline compound used in the developer of the radiation-sensitive composition of the present invention include inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, and the like. primary amines such as n-propylamine; secondary amines such as diethylamine and di-n-propylamine; tertiary amines such as triethylamine and N, N-diethylmethylamine; tetramethylammonium hydroxide And quaternary ammonium compounds such as trimethylhydroxyethylammonium hydroxide. Among them, quaternary ammonium hydroxides are preferable, and tetramethylammonium hydroxide is particularly preferable. Furthermore, in addition to these alkaline compounds,
Alcohol, a surfactant and the like can be added for use. The radiation-sensitive composition of the present invention is useful not only for the production of VLSI, but also for general IC production, mask production, image formation, liquid crystal screen production, color filter production or lithographic printing. In particular, it is useful for producing a semiconductor integrated circuit.

[0035]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited by the examples unless it exceeds the gist thereof.

Synthesis Example 1 1 L equipped with a stirrer, a dropping funnel and a reflux condenser
In a reactor, 100 g of poly (p-hydroxystyrene) (weight average molecular weight 15000) and 1,3-dioxolane 3 were added.
After charging 00 mL and dissolving uniformly, 0.25 mL of 35% hydrochloric acid was further added as a catalyst. A solution obtained by diluting 44.2 g of ethyl vinyl ether with 40 mL of 1,3-dioxolane was added thereto through a dropping funnel and reacted at 30 ° C. for 3 hours. After the reaction, the pH of the reaction solution was adjusted to 10 with aqueous ammonia, and 3 L of this solution was added.
Of pure water was precipitated. The acetalized product was purified by dissolving it again in 400 mL of 1,3-dioxolane, dropping it again into 3 L of water, and reprecipitating it. The obtained acetalized product was dried under vacuum to obtain 110 g of a partially acetalized product of poly (p-hydroxystyrene) (the protecting group corresponds to a 1-ethoxyethyl group). Dissolve this in heavy acetone,
The acetalization rate was measured by a proton NMR spectrum. The above operation was repeated three times to produce three acetalized products. (Synthesis example 1-a, b, c)

Synthesis Example 2 The same procedure was performed as in Synthesis Example 1 except that ethyl vinyl ether was added dropwise to the reaction solution without dilution with 1,3-dioxolan. This operation was repeated three times as in Synthesis Example 1 to produce three acetalized products. (Synthesis Example 2-a, b, c)

Example 1 To the acetalized product (1.0 g) obtained in Synthesis Example 1, 0.02 g of cyclohexylsulfonyl- (4-methoxyphenylsulfonyl) diazomethane was added as a photoacid generator.
Then, 5.35 g of propylene glycol monomethyl ether acetate was mixed, and tetraisopropanolamine was added at 15 mol% of a photoacid generator to prepare a resist photosensitive solution. This photosensitive solution is spin-coated on a wafer having a lower organic anti-reflection film coated on a silicon substrate, and baked on a hot plate at 90 ° C. for 60 seconds to give a film thickness of 0.72 μm.
m of the resist film. Further, an aqueous solution containing 1.2% by weight of polyvinylpyrrolidone and 3.5% by weight of ammonium perfluorooctylsulfonate was applied on the resist film to form an antireflection film for an upper layer. The resist film on this substrate was exposed using a KrF excimer laser reduction projection exposure apparatus (NA = 0.42) manufactured by Nikon Corporation, and baked on a hot plate at 110 ° C. for 60 seconds. Thereafter, the resist film was developed with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 1 minute. By observing the resist pattern obtained after the development with a scanning electron microscope, the sensitivity, that is, the line pattern of 0.30 μm was obtained.
And space - the scan pattern is 1: exposure amount that was resolved in 1 were evaluated (hereinafter, to represent E _0). This operation was performed once for each of the three acetalized products produced in Synthesis Example 1, for a total of three times. (Example 1-a, b, c)

Comparative Example 1 The procedure of Example 1 was repeated, except that the acetalized product obtained in Synthesis Example 2 was used. This operation was performed once for each of the three acetalized products produced in Synthesis Example 2, for a total of three times. (Comparative Examples 1-a, b, c) Table 1 shows the results of Example 1 and Comparative Example 1.

[0040]

[Table 1]

Since the protection rate is more stable in the example than in the comparative example, it can be seen that the sensitivity, that is, E ₀ is stable, and the performance of the photosensitive solution is stable.

[0042]

According to the method of the present invention, an acetal compound used particularly for a radiation-sensitive composition can be stably and effectively produced with a desired protection rate. In addition, the radiation-sensitive composition containing an acetalized product produced by this method does not vary in performance such as sensitivity between production lots, and can always provide stable performance, and can produce ICs with good yield. This is extremely useful in practice.

Continuation of Front Page (71) Applicant 596 156 668 455 Forest Street, Marlborough, MA 01752 U.S.A. A (72) Inventor Toichi Ochiai 1000 Kamoshita-cho, Aoba-ku, Yokohama-shi, Kanagawa Prefecture Mitsubishi Chemical Corporation Yokohama Research Laboratory (72) Inventor Yasuhiro Kameyama 1000 Kamoshita-cho, Aoba-ku, Yokohama-shi, Kanagawa Mitsubishi Chemical Corporation Yokohama F-term in the laboratory (reference) 2H025 AA00 AA01 AB16 AC01 AC06 AC08 AD03 BE00 BE10 BG00 BJ10 CC20 FA03 FA12 FA17 4J100 AB02Q AB07P AD02Q AJ02Q BA02H BA02P BA03P BA04H BA04P BA05H BA05P BA06H BA31 HBAP CA43B43P HB52 HC13 HC27 HC38 HC42 HC43 HC44 HC45 HC63 HC71 HC75 HE14 JA38

Claims (4)

[Claims] 1. Polyvinylphenols (A) and> C
A compound (B) having a partial structure of う る C—O— and capable of forming an acetal structure by reacting with the polyvinylphenols (A) is reacted in the presence of an organic solvent to form a polyvinylphenols. A method for producing a compound in which at least a part of a phenolic hydroxyl group is acetalized, wherein the compound (B) is preliminarily mixed with an organic solvent, then mixed with a polyvinyl phenol and reacted. Method for producing acetalized compound. 2. The method according to claim 1, wherein the compound (B) is an alkyl vinyl ether. 3. The process according to claim 1, wherein the reaction is carried out in the presence of an acid catalyst, and the obtained reaction solution is neutralized with a basic compound. 4. A photosensitizer comprising an acetalized product of a polyvinyl phenol obtained by the method according to claim 1 and a radiation-sensitive compound which generates an acid by the action of radiation. Radioactive composition.