JPH08194312A - Positive type resist composition - Google Patents

Abstract

PURPOSE: To obtain a positive type resist excellent in sensitivity, resolution, pattern shape, etc., and fit for fine working by incorporating alkali-soluble phenolic resin, a quinonediazidesulfonic ester type photosensitive agent and a phenol compd. having specified structural units. CONSTITUTION: This resist compsn. contains alkali-soluble phenolic resin, a quinonediazidesulfonic ester type photosensitive agent and a phenol compd. having structural units represented by the formula, wherein each of R1-R3 is H, hydroxyl, halogen, substitutable alkyl, substitutable cycloalkyl, substitutable alkenyl, substitutable alkoxy or substitutable aryl and each of R4-R11 is H, substitutable alkyl, substitutable cycloalkyl, substitutable alkenyl or substitutable aryl. The wt. average mol.wt. (expressed in terms of polystyrene) of the phenol compd. in a pattern by GPC using a detector with UV of 254nm is <=2,000.

Description

Detailed Description of the Invention

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positive resist composition, and more particularly to a positive resist composition for microfabrication required for manufacturing semiconductor devices, magnetic bubble memory devices, integrated circuits and the like.

[0003]

2. Description of the Related Art As a resist composition for forming a semiconductor device, a positive resist composition has been predominant in recent years. This is because the negative resist composition has high sensitivity, but since an organic solvent is used for development, swelling is large and there is a difficulty in resolution, and the positive resist composition is excellent in resolution. Therefore, it is considered that it is possible to sufficiently cope with high integration of semiconductors. Conventionally, a positive resist composition generally used in this field comprises an alkali-soluble resin such as a novolac resin and a quinonediadisulfonic acid compound. Since this positive resist composition is developed with an alkaline aqueous solution, it does not swell and is excellent in resolution. Further, such a positive resist composition has further improved the resolution due to the performance improvement of itself and the high performance of the exposure device, and it has become possible to form a fine pattern of 1 μm or less.

However, conventional positive resist compositions have not always been satisfactory in terms of various characteristics such as sensitivity, residual film rate, resolution, heat resistance and storage stability.
Further improvement in performance is desired. In particular, in forming a fine pattern of 0.8 μm or less, it is necessary to more strictly control the resist dimension, and therefore, a positive resist composition having higher dimensional accuracy has been strongly demanded. From this point of view, it has been proposed to use various phenol compounds as additives (JP-A-3-200252, JP-A-4-122938, JP-A-5-127374, and JP-A-5-2332697).
issue). However, the positive resist compositions specifically disclosed in these documents have somewhat insufficient resist properties such as sensitivity, resolution and residual film rate, and further improvement is required.

[0005]

Under the above-mentioned conventional techniques, the inventors of the present invention have earnestly studied to solve the above-mentioned problems, and as a result, found that the use of a specific phenol compound can achieve the above-mentioned object. The present invention has been completed and the present invention has been completed.

[0006]

Thus, according to the present invention, an alkali-soluble phenol resin, a quinonediazide sulfonic acid ester-based photosensitizer and a phenol compound having a structural unit represented by the following general formula (I) are contained. A featured positive resist composition is provided.

Embedded image (In the formula, R1 to R3 are each independently a hydrogen atom, a hydroxyl group, a halogen atom, a substitutable alkyl group, a substitutable cycloalkyl group, a substitutable alkenyl group, a substitutable alkoxy group, or a substitutable aryl group. To R11 are independently a hydrogen atom, a substitutable alkyl group, a substitutable cycloalkyl group, a substitutable alkenyl group, or a substitutable aryl group.)

The present invention will be described in detail below. (A) Alkali-soluble phenol resin In the present invention, the alkali-soluble phenol resin may be used alone or in combination of two or more kinds.

Specific examples of the alkali-soluble phenolic resin include, for example, condensation reaction products of phenols and aldehydes, condensation reaction products of phenols and ketones, vinylphenol-based polymers, isopropenylphenol-based polymers. In combination, hydrogenation reaction products of these phenol resins and the like can be mixed and used. Specific examples of the phenols used here include phenol and o-
Cresol, m-cresol, p-cresol, 2,3
-Dimethylphenol, 2,5-dimethylphenol,
3,4-dimethylphenol, 3,5-dimethylphenol, 2,4-dimethylphenol, 2,6-dimethylphenol, 2,3,5-trimethylphenol, 3,
4,5-Trimethylphenol, 2-t-butylphenol, 3-t-butylphenol, 4-t-butylphenol, 2-methylresorcinol, 4-methylresorcinol, 5-methylresorcinol, 4-t-butylcatechol, 2-methoxy. Phenol, 3-methoxyphenol, 2-propylphenol, 3-propylphenol, 4-propylphenol, 2-isopropylphenol, 3-isopropylphenol, 4-isopropylphenol, 2-methoxy-5-methylphenol, 2-t- Butyl-5-methylphenol, thymol, isothymol and the like are exemplified. Of these, o
-Cresol, m-cresol, p-cresol, 2,
3-dimethylphenol, 2,5-dimethylphenol, 3,4-dimethylphenol, 3,5-dimethylphenol, 2,3,5-trimethylphenol, 3,
A preferred example is 4,5-trimethylphenol. These compounds may be used alone or in combination of two or more.

Specific examples of the aldehydes include formalin, paraformaldehyde, trioxane, acetaldehyde, propylaldehyde, benzaldehyde, phenylacetaldehyde, α-phenylpropylaldehyde, β-phenylpropylaldehyde, o-hydroxybenzaldehyde, m-hydroxybenzaldehyde,
p-hydroxybenzaldehyde, o-chlorobenzaldehyde, m-chlorobenzaldehyde, p-chlorobenzaldehyde, o-nitrobenzaldehyde, m-nitrobenzaldehyde, p-nitrobenzaldehyde,
Examples include o-methylbenzaldehyde, m-methylbenzaldehyde, p-methylbenzaldehyde, p-ethylbenzaldehyde, pn-butylbenzaldehyde, terephthalaldehyde and the like. Of these, formalin, paraformaldehyde, acetaldehyde and benzaldehyde are preferable. These compounds may be used alone or in combination of two or more.
Specific examples of the ketones include acetone, methyl ethyl ketone, diethyl ketone, diphenyl ketone and the like. These compounds may be used alone or in combination of two or more. These condensation reaction products can be obtained by a conventional method, for example, by reacting phenols with aldehydes or ketones in the presence of an acidic catalyst.

The vinylphenol polymer is selected from a homopolymer of vinylphenol and a copolymer of vinylphenol and a component copolymerizable with vinylphenol. The isopropenylphenol polymer is a polymer of isopropenylphenol. It is a homopolymer or a copolymer of a component capable of copolymerizing with isopropenylphenol. Specific examples of components copolymerizable with vinylphenol and isopropenylphenol include acrylic acid, methacrylic acid, styrene,
Examples thereof include maleic anhydride, maleic imide, vinyl acetate, acrylonitrile, and their derivatives. The copolymer can be obtained by a known method. The hydrogenation reaction product of a phenol resin is obtained by a conventional method, for example, by dissolving the above-mentioned phenol resin in an organic solvent and hydrogenating it in the presence of a homogeneous or heterogeneous catalyst.

GP using UV-254 nm detector of alkali-soluble phenol resin used in the present invention
The polystyrene-equivalent weight average molecular weight (hereinafter, simply referred to as average molecular weight) according to the C pattern varies depending on the type of resin and the production method, but is usually 2,000 to 25,000, and preferably 3,500 to 20,000. Average molecular weight 3,5
If it is less than 00, the pattern shape, resolution and developability tend to deteriorate, and if it is less than 2,000, it is not practical. Further, if it exceeds 20,000, the pattern shape, developability and sensitivity are deteriorated, and if it exceeds 25,000, it is not practical.

These alkali-soluble phenolic resins can be used by controlling the molecular weight and the molecular weight distribution by known means. As a method for controlling the molecular weight and the molecular weight distribution, the resin is crushed, and solid-liquid extraction is performed with an organic solvent having an appropriate solubility, or the resin is dissolved in a good solvent and then dropped into a poor solvent, or a poor solvent is used. Is added dropwise to perform solid-liquid or liquid-liquid extraction.

(B) Photosensitizer The photosensitizer used in the present invention is a quinonediazide sulfonic acid ester of a polyhydroxy compound.
All the hydroxyl groups in the molecule do not have to be esterified, and may be partially esterified products. Specific examples of the esterified product used as a photosensitizer include:
1,2-benzoquinonediazide-4-sulfonic acid ester, 1,2-naphthoquinonediazide-4-sulfonic acid ester, 1,2-naphthoquinonediazide-5-sulfonic acid ester, 1,2-of these polyhydroxy compounds
Naphthoquinonediazide-6-sulfonate, 2,
1-naphthoquinonediazide-4-sulfonic acid ester,
Examples thereof include 2,1-naphthoquinonediazide-5-sulfonic acid ester and 2,1-naphthoquinonediazide-6-sulfonic acid ester. The quinonediazide sulfonic acid ester of a polyhydroxy compound is obtained by converting a quinonediazidesulfonic acid compound into a quinonediazidesulfonic acid halide according to a conventional method, and then using sodium carbonate, sodium hydrogen carbonate, sodium hydroxide or hydroxide in a solvent such as acetone, dioxane or tetrahydrofuran. In the presence of an inorganic base such as potassium or an organic base such as trimethylamine, triethylamine, tripropylamine, diisopropylamine, tributylamine, pyrrolidine, piperidine, piperazine, morpholine, pyridine, dicyclohexylamine, a quinonediazide sulfonic acid halide and a polyhydroxy compound, The quinonediazide sulfonic acid ester-based photosensitizer used in the present invention can be obtained by reacting As the hydroxy compound used here, a known one having a phenol group is used, and specific examples thereof include 2,3,4-trihydroxybenzophenone, 2,4,4′-trihydroxybenzophenone,
2,3,4,4'-tetrahydroxybenzophenone,
Polyhydroxybenzophenones such as 2,4,2 ', 4'-tetrahydroxybenzophenone and 2,3,4,2', 4'-pentahydroxybenzophenone; gallic acid such as methyl gallate, ethyl gallate and propyl gallate Acid esters; polyhydroxybisphenylalkanes such as 2,2-bis (4-hydroxyphenyl) propane and 2,2-bis (2,4-dihydroxyphenyl) propane; tris (4-hydroxyphenyl) methane,
1,1,1-tris (4-hydroxy-3-methylphenyl) ethane, 1,1,1-tris (4-hydroxy-)
3-methylphenyl) ethane, 1,1,1-tris (4
-Hydroxyphenyl) ethane, 1,1-bis (4-hydroxy-3-methylphenyl) -1- (4-hydroxyphenyl) ethane, bis (4-hydroxy-3-methylphenyl) -2-hydroxy-4- Polyhydroxytrisphenylalkanes such as methoxyphenylmethane;
1,1,2,2-tetrakis (4-hydroxyphenyl) ethane, 1,1,2,2-tetrakis (3-methyl-4-hydroxyphenyl) ethane, 1,1,3,3-
Polyhydroxytetrakisphenylalkanes such as tetrakis (4-hydroxyphenyl) propane; α, α,
α ′, α′-tetrakis (4-hydroxyphenyl)-
3-xylene, α, α, α ′, α′-tetrakis (4-
Hydroxyphenyl) -4-xylene, α, α, α ′,
Polyhydroxytetrakiphenyl xylenes such as α'-tetrakis (3-methyl-4-hydroxyphenyl) -3-xylene; 2,6-bis (2,4-dihydroxybenzyl) -p-cresol, 2,6- Bis (2,4-dihydroxy-3-methylbenzyl) -p-cresol,
4,6-bis (4-hydroxybenzyl) resorcin,
4,6-bis (4-hydroxy-3-methylbenzyl)
Resorcin, 4,6-bis (4-hydroxybenzyl)
Trimer of phenol such as 2-methylresorcin, 4,6-bis (4-hydroxy-3-methylbenzyl) -2-methylresorcin and formalin, phenol represented by the following general formula (II) and formalin And a novolac resin.

Embedded image (In the formula, R12 and R13 are independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R14 to R17 are independently an alkyl group having 1 to 4 carbon atoms.)

In the photosensitizer used in the present invention, the ratio of esterification of quinonediazide sulfonic acid compound to these polyhydroxy compounds (average esterification rate)
Is not particularly limited, but the lower limit is usually 20%, preferably 30% as the mol% of the quinonediazide sulfonic acid compound relative to the hydroxyl group of the polyhydroxy compound, and the upper limit is usually 100%, preferably 95%. If the esterification ratio is too low, the pattern shape and resolution may be deteriorated, and if the esterification ratio is too high, the sensitivity may be deteriorated.

The photosensitizers used in the present invention may be used alone or in admixture of two or more. The amount of the photosensitizer is usually 1 to 100 parts by weight, based on 100 parts by weight of the alkali-soluble phenol resin (a).
Preferably it is 3 to 40 parts by weight. If the amount is less than 1 part by weight, it becomes difficult to form a pattern, and if it exceeds 100 parts by weight, the sensitivity is lowered and the undeveloped portion is liable to occur.

(C) Phenol Compound The phenol compound used in the present invention is one having a structural unit represented by the above formula (I) (hereinafter sometimes referred to as phenol compound (c)). The compound can be obtained by condensing phenols and α, α′-2 substituted xylenes in the presence of an acid catalyst. The phenols used here are not particularly limited and known ones can be used, but preferred examples include phenol, o-cresol, m-cresol, p-cresol, 2,3-dimethylphenol,
2,5-dimethylphenol, 3,4-dimethylphenol, 3,5-dimethylphenol, 2,4-dimethylphenol, 2,6-dimethylphenol, 2,3,5
-Trimethylphenol, 3,4,5-trimethylphenol, 2-t-butylphenol, 3-t-butylphenol, 4-t-butylphenol, resorcinol, 2-methylresorcinol, 4-methylresorcinol, 5-methylresorcinol, catechol, 4-t
-Butylcatechol, 2-methoxyphenol, 3-methoxyphenol, 2-propylphenol, 3-propylphenol, 4-propylphenol, 2-isopropylphenol, 3-isopropylphenol, 4-
Examples thereof include isopropylphenol, 2-methoxy-5-methylphenol, 2-t-butyl-5-methylphenol, pyrogallol, thymol and isothymol. These compounds may be used alone or in combination of two or more. As the α, α′-2 substituted xylenes, known ones can be used without particular limitation, and preferred specific examples are o-xylylene glycol, m-xylylene glycol, p-xylylene. Glycol, o-divinylbenzene, m-divinylbenzene, p-divinylbenzene, o-xylylene glycol ditoluene sulfonate, m-xylylene glycol ditoluene sulfonate, p-xylylene glycol ditoluene sulfonate, o- Xylylene glycol dimesylate, m-xylylene glycol dimesylate, p-xylylene glycol dimesylate, o-diisopropenylbenzene, m-diisopropenylbenzene, p-diisopropenylbenzene, 2,3,3 5,6-
Examples thereof include tetramethyl-p-xylylene glycol and 2,5-dimethyl-p-xylylene glycol. The polystyrene equivalent weight average molecular weight (hereinafter, simply referred to as average molecular weight) of the phenol compound (c) used in the present invention has an upper limit of usually 2,000 or less, preferably 1,500 or less. In the GPC pattern, the average molecular weight of 2,000 or more is usually 3
It is 0% or less, preferably 20% or less.

These phenol compounds (c) can also be used as those whose molecular weight and molecular weight distribution are controlled by known means. As a method for controlling the molecular weight and the molecular weight distribution, the resin is crushed, and solid-liquid extraction is performed with an organic solvent having an appropriate solubility, or the resin is dissolved in a good solvent and then dropped into a poor solvent, or a poor solvent is used. Is added dropwise to perform solid-liquid or liquid-liquid extraction. Specific examples of such a phenol compound (c) include those shown in Table 1.

[0018]

[Table 1]

In the present invention, a phenol compound other than the general formula (I) (hereinafter sometimes referred to as another phenol compound) may be used in combination, and high resist properties may be obtained in some cases. Specific examples of other phenol compounds that can be used in combination include monophenols such as p-phenylphenol and p-isopropylphenol; biphenol, 4,4′-dihydroxydiphenyl ether, 4,4′-dihydroxybenzophenone, bisphenol A (Honshu). Chemical Industry Co., Ltd., Bisphenol C (Honshu Chemical Industry Co., Ltd.), Bisphenol E (Honshu Chemical Industry Co., Ltd.), Bisphenol F (Honshu Chemical Industry Co., Ltd.), Bisphenol AP (Honshu Chemical Industry Co., Ltd.), Bisphenol M (Mitsui Petrochemical Industry Co., Ltd.), bisphenol P (Mitsui Petrochemical Industry Co., Ltd.), bisphenol Z (Honshu Chemical Industry Co., Ltd.), 1,1-bis (4-hydroxyphenyl) cyclopentane, 9,9-bis (4-) Hydroxyphenyl) fluorene, 1,1-bis (5-methyl-2)
-Hydroxyphenyl) methane, 3,5-dimethyl-4
-Bisphenols such as hydroxybenzylphenol; 1,1,1-tris (4-hydroxyphenyl) methane, 1,1,1-tris (4-hydroxyphenyl)
Ethane, 1,1-bis (3-methyl-4-hydroxyphenyl) -1- (4-hydroxyphenyl) methane,
1,1-bis (2,5-dimethyl-4-hydroxyphenyl) -1- (2-hydroxyphenyl) methane, 1,
1-bis (3,5-dimethyl-4-hydroxyphenyl) -1- (2-hydroxyphenyl) methane, 2,6
-Bis (5-methyl-2-hydroxybenzyl) -4-
Methylphenol, 2,6-bis (4-hydroxybenzyl) -4-methylphenol, 2,6-bis (3-methyl-4-hydroxybenzyl) -4-methylphenol, 2,6-bis (3,5) -Dimethyl-4-hydroxybenzyl) -4-methylphenol, Trisphenol-PA (manufactured by Honshu Chemical Industry Co., Ltd.), Trisphenol-TC
Trisphenols such as (manufactured by Honshu Chemical Industry Co., Ltd.); 1,
1,2,2-tetrakis (4-hydroxyphenyl) ethane, 1,1,2,2-tetrakis (3-methyl-4-)
Hydroxyphenyl) ethane, 1,1,3,3- (4-
Hydroxyphenyl) propane, 1,1,5,5-tetrakis (4-hydroxyphenyl) pentane, α, α,
α ′, α′-tetrakis (4-hydroxyphenyl)-
3-xylene, α, α, α ′, α′-tetrakis (4-
Hydroxyphenyl) -4-xylene, α, α, α ′,
Tetrakisphenols such as α'-tetrakis (3-methyl-4-hydroxyphenyl) -3-xylene, α, α, α ', α'-tetrakis (3-methyl-4-hydroxyphenyl) -4-xylene, etc. Is exemplified. Of these, trisphenols and tetrakisphenols are particularly preferable examples.

The addition amount of these (C) phenolic compounds varies depending on the composition of the alkali-soluble phenolic resin, the molecular weight, the molecular weight distribution, and the kind and amount of other additives, but the total phenolic compound amount (that is, the phenolic compound ( c) The amount of the phenol compound (c) when alone, the total amount of the phenol compound (c) and the other phenol compound when the phenol compound (c) and the other phenol compound are used in combination) is an alkali-soluble phenol resin. With respect to 100 parts by weight, the upper limit is usually 100 parts by weight, preferably 60 parts by weight, more preferably 40 parts by weight, and the lower limit is usually 3 parts by weight, preferably 5 parts by weight, more preferably 10 parts by weight. . When the phenol compound (c) is used in combination with another phenol compound, the phenol compound (c) 10
The upper limit of other phenol compounds is usually 9 parts by weight with respect to 0 parts by weight.
The amount is 00 parts by weight or less, preferably 400 parts by weight or less, more preferably 100 parts by weight or less. The lower limit of the amount of the other phenol compound used can be arbitrarily selected within a range not exceeding the upper limit.

The positive resist composition of the present invention is usually dissolved in a solvent and used in order to form a resist film by coating it on a substrate. Specific examples of the solvent usable in the present invention include ketones such as acetone, methyl ethyl ketone, cyclopentanone and cyclohexanone; alcohols such as n-propyl alcohol, isopropyl alcohol, n-butyl alcohol and cyclohexanol; ethylene. Ethers such as glycol dimethyl ether, ethylene glycol diethyl ether, dioxane; alcohol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether; propyl formate, butyl formate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, Methyl butyrate,
Esters such as ethyl butyrate, methyl lactate, ethyl lactate; cellosolve acetates such as cellosolve acetate, methyl cellosolve acetate, ethyl cellosolve acetate, propyl cellosolve acetate, butyl cellosolve acetate; propylene glycol, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether. Propylene glycols such as acetate and propylene glycol monobutyl ether; Diethylene glycols such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether and diethylene glycol diethyl ether; halogenated hydrocarbons such as trichloroethylene; aromatics such as toluene and xylene Hydrogen like; dimethylacetamide, dimethylformamide, such as a polar solvent such as N- methyl acetamide and the like, which may be used by either singly or in combination.

The positive resist composition of the present invention may optionally contain a copolymer of styrene and acrylic acid, methacrylic acid or maleic anhydride in order to improve developability, storage stability and heat resistance. , A copolymer of an alkene and maleic anhydride, a vinyl alcohol polymer, a vinylpyrrolidone polymer, rosin, shellac and the like can be added. The amount of such a polymer added is 0 to 100 parts by weight of the total alkali-soluble phenol resin.
50 parts by weight, preferably 5 to 20 parts by weight.

The positive resist composition of the present invention may contain compatible additives such as a surfactant, a storage stabilizer, a sensitizer, a striation inhibitor and a plasticizer, if necessary. it can. Examples of the surfactant include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, and polyoxyethylene oleyl ether; polyoxyethylene octylphenyl ether, polyoxyethylene nonylphenol ether, and the like. Oxyethylene aryl ethers; polyethylene glycol dialkyl esters such as polyethylene glycol dilaurate and ethylene glycol distearate; Ftop EF301, EF303, EF352 (manufactured by Shin-Akita Kasei Co., Ltd.), Megafax F171, F172, F173,
F177 (manufactured by Dainippon Ink and Chemicals), Florard FC43
0, FC431 (Sumitomo 3M), Asahi Guard AG710, Surflon S-382, SC-10.
1, SC-102, SC-103, SC-104, SC
-105, SC-106 (manufactured by Asahi Glass Co., Ltd.) and the like; organosiloxane polymer KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.); acrylic acid-based or methacrylic acid-based (co) polymer polyflow No. 75, no. 95 (manufactured by Kyoeisha Oil and Fat Chemical Co., Ltd.). The amount of these surfactants to be compounded is usually 2 parts by weight or less, preferably 1 part by weight or less, per 100 parts by weight of the solid content of the composition. The resist composition of the present invention generally uses an alkaline aqueous solution as an alkaline developing solution, and specific examples thereof include aqueous solutions of inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium silicate, and ammonia; ethylamine, propylamine, and the like. Aqueous solution of primary amines; Aqueous solution of secondary amines such as diethylamine and dipropylamine; Aqueous solution of tertiary amines such as trimethylamine and triethylamine; Aqueous solution of alcohol amines such as diethylethanolamine and triethanolamine; Tetramethylammonium hydroxy , Tetraethylammonium hydroxide, trimethylhydroxymethylammonium hydroxide, triethylhydroxymethylammonium hydroxide, trimethylhydroxyethylammonium hydroxide Etc. Any quaternary ammonium hydroxide solution and the like. Further, if necessary, a water-soluble organic solvent such as methanol, ethanol, propanol, or ethylene glycol, a surfactant, a resin dissolution inhibitor, or the like can be added to the alkaline aqueous solution.

A resist film can be formed by applying a resist solution prepared by dissolving the resist composition of the present invention in a solvent onto the surface of a substrate such as a silicon wafer by a conventional method and then removing the solvent by drying. Spin coating is particularly recommended as the coating method at this time. Examples of the exposure source used in the exposure for forming the pattern on the resist film thus obtained include ultraviolet rays, far ultraviolet rays, KrF excimer laser light, electron beam sources such as X-rays and electron beams. Furthermore, it is preferable to perform heat treatment (post-exposure bake) after the exposure because the sensitivity can be improved and stabilized.

The preferred embodiments of the present invention are shown below, but the present invention is not limited thereto. In a positive resist composition containing an alkali-soluble phenol resin, a quinonediazide sulfonic acid ester-based photosensitizer and a phenol compound, a phenol compound having a structural unit represented by the general formula (I) and a phenol compound other than the phenol compound A positive resist composition comprising a phenol compound. A positive resist composition in which the phenol compound other than the phenol compound having the structural unit represented by formula (I) is trisphenol or tetrakisphenol. The positive resist composition as described above, wherein a phenol compound other than the phenol compound is used in a proportion of 900 parts by weight or less based on 100 parts by weight of the phenol compound having the structural unit represented by the formula (I). In a positive resist composition containing an alkali-soluble phenol resin, a quinonediazide sulfonic acid ester-based photosensitizer, and a phenol compound, the upper limit of the phenol compound is 100 parts by weight and the lower limit is 3 parts by weight, relative to 100 parts by weight of the alkali-soluble phenol resin. The positive resist composition containing. In a positive resist composition containing an alkali-soluble phenolic resin, a quinonediazide sulfonic acid ester-based photosensitizer and a phenolic compound, the phenolic compound has an upper limit of 60 parts by weight and a lower limit of 3 parts by weight with respect to 100 parts by weight of the alkali-soluble phenolic resin. The positive resist composition containing. In a positive resist composition containing an alkali-soluble phenol resin, a quinonediazide sulfonic acid ester-based photosensitizer, and a phenol compound, the phenol compound is contained in an upper limit of 100 parts by weight and a lower limit of parts by weight with respect to 100 parts by weight of the alkali-soluble phenol resin. Is a positive resist composition. In a positive resist composition containing an alkali-soluble phenol resin, a quinonediazide sulfonic acid ester-based photosensitizer and a phenol compound, the upper limit of the phenol compound is 5 parts by weight and the lower limit is 3 parts by weight with respect to 60 parts by weight of the alkali-soluble phenol resin. The positive resist composition containing.

[0026]

EXAMPLES The present invention will be described in more detail below with reference to synthesis examples and examples. Parts and% in each example are based on weight unless otherwise specified.

(Synthesis Example 1) Synthesis of Novolac Resin A-1 In a 2 liter flask equipped with a cooling pipe and a stirrer,
m-cresol 462g, p-cresol 308g, 3
360 g of 7% formalin and oxalic acid dihydrate 2.49
g was added and the reaction was carried out for 2 hours while maintaining the temperature at 95 to 100 ° C. After that, water was distilled off at 100 to 105 ° C. for 2 hours, and the temperature was raised to 180 ° C. to 10 mmH.
After reducing the pressure to g and removing unreacted monomers and water,
After returning to room temperature and collecting, 515 g of novolak resin A-1
Obtained. The polystyrene-reduced weight average molecular weight (Mw) of this novolac resin A-1 was measured by GPC and found to be 6000.

Synthesis Example 2 Synthesis of Novolak Resin A-2 380 g of the novolak resin obtained in Synthesis Example 1 and 360 g of ethyl cellosolve acetate were added and dissolved. A dropping funnel was attached to the flask, and 950 g of toluene was added dropwise from the dropping funnel while controlling the temperature at 80 to 85 ° C, and further heated at 80 ° C for 1 hour. The mixture was gradually cooled to room temperature and left still for 1 hour. The supernatant of the precipitated resin component was removed by decantation, 570 g of ethyl lactate was added, and the mixture was heated to 100 ° C. at 100 mmHg to remove residual toluene to obtain an ethyl lactate solution of novolak resin A-2. The polystyrene-reduced weight average molecular weight (Mw) of this novolak resin was measured by GPC to find that it was 9800.
Met.

(Synthesis Example 3) Synthesis of Novolac Resin A-3 In a 2 liter flask equipped with a cooling pipe and a stirrer,
280 g of m-cresol, 210 g of p-cresol,
265 g of 2,3,5-trimethylphenol, 368 g of 37% formalin and 2.49 g of oxalic acid dihydrate were added, and the reaction was carried out for 2 hours while maintaining the temperature at 95 to 100 ° C.
Then, the water was distilled off at 100 to 105 ° C. for 2 hours,
Furthermore, the temperature was raised to 180 ° C. and the pressure was reduced to 10 mmHg to remove unreacted monomers and water, and then the temperature was returned to room temperature and recovered to obtain 675 g of novolak resin A-3.
The polystyrene-reduced weight average molecular weight (Mw) of this novolak resin A-3 was measured by GPC and found to be 6400.

(Synthesis Example 4) Synthesis of Novolac Resin A-4 380 g of the novolak resin obtained in Synthesis Example 3 and 3800 g of toluene were added and dissolved. After heating at 80 ° C. for 1 hour, the mixture was gradually cooled to room temperature and left still for 1 hour. After removing the supernatant liquid of the precipitated resin component by decantation, 570 g of ethyl lactate was added, and 100 mmHg was added to 1
Residual toluene was removed by heating to 00 ° C to obtain an ethyl lactate solution of novolak resin A-4. The polystyrene-equivalent weight average molecular weight (M
When w) was measured, it was 9800.

(Synthesis Example 5) Synthesis of Photosensitizer B-1 Novolak resin A-1 was used as a polyhydroxy compound, and 1,2-naphthoquinonediazide-5-sulfonic acid chloride was used as a quinonediazidesulfonic acid compound. (Mole% corresponding to a rate of 40%) was dissolved in acetone to obtain a 10% solution. While controlling the temperature at 20 to 25 ° C, 1.2 equivalents of triethylamine of 1,2-naphthoquinonediazide-5-sulfonic acid chloride was added dropwise over 30 minutes, and the reaction temperature was maintained for 2 hours for reaction. Was completed. The precipitated salt was separated by filtration and put into a 0.2% aqueous solution of oxalic acid in an amount 10 times as much as the reaction solution.
The solid content that has precipitated is filtered, washed with ion-exchanged water, and dried to give a quinonediazide sulfonic acid ester-based photosensitizer B-
Got 1.

(Synthesis Example 6) Synthesis of Photosensitizer B-2 As a polyhydroxy compound, R represented by the general formula (II) is used.
12 = R13 = H, R14 = R15 = R16 = R17 = with CH _3, compound corresponds to the amount of the quinonediazide sulfonic compound 1,2-naphthoquinonediazide-5-sulfonic acid chloride in the esterification 70% A quinonediazide sulfonic acid ester-based photosensitizer B-2 was obtained by the same operation as in Synthesis Example 5 except that the mol% was used.

(Synthesis Example 7) Acquisition of Phenolic Compound (c) XYLOCK Resin "XL-225-L" manufactured by Mitsui Toatsu Chemicals, Inc.
L "," XL-225-3L "or" XL-225- "
4 L ”was used as a good solvent in ethyl cellosolve acetate and toluene as a poor solvent, and fractionation operation was performed to obtain a resin having an average molecular weight (Mw) shown in Table 2.

The resist evaluation methods in the following examples and comparative examples are as follows. All resist evaluations were performed on a silicon wafer. (1) Sensitivity 0.60 μm 1: 1 line & space can be formed according to the design dimension, and the exposure energy amount can be defined as exposure time (unit: ms
The value represented by ec). (2) Resolution This represents the limit resolution (μm) under the above exposure conditions. (3) Remaining film ratio This represents the ratio (%) of the resist film thickness before and after the development of the portion where the pattern is not formed on the wafer. (4) Pattern shape The wafer on which the resist pattern was formed was cut from the direction perpendicular to the line pattern, and the result of observation with an electron microscope from the cross-sectional direction of the pattern was shown. The pattern side wall was raised at an angle of 80 degrees or more with respect to the substrate, and a film having no film reduction was judged to be good. The film loss was recognized as "film loss".

(Examples 1 to 9 and Comparative Examples 1 and 2) 30 parts by weight of the resin and the photosensitizer shown in Table 2 were dissolved in ethyl lactate,
The amount of solvent blended was adjusted so that the coating could be applied to a film thickness of 1.17 μm. These solvents were filtered with a 0.1 μm Teflon filter (polytetrafluoroethylene filter) to prepare a resist solution. However, Comparative Examples 1 and 2 are examples containing 20 parts by weight of trisphenol PA (manufactured by Honshu Chemical Industry Co., Ltd.) as a phenol compound.

After coating the above resist solution on a silicon wafer with a coater, prebaking was performed at 90 ° C. for 90 seconds to form a resist film having a thickness of 1.17 μm. This wafer was exposed using an i-line stepper NSR1755i7A (manufactured by Nikon Corporation; NA = 0.50) and a test reticle while varying the exposure time, and then the wafer was exposed at 60 ° C. at 110 ° C.
Second exposure bake (Post Exposure Ba
king). Next, it was developed by a paddle method at 23 ° C. for 1 minute with a 2.38% tetramethylammonium hydroxide aqueous solution to form a positive pattern. This wafer was taken out and observed with an electron microscope to observe the sensitivity, resolution, residual film rate, and pattern shape. Table 2 shows the results.

[0037]

[Table 2]

From these results, it was found that the addition of the phenol compound (c) improves the sensitivity, the residual film rate, the resolution and the pattern shape. It was also found that the effect is further improved by using other phenol compounds together.

[0039]

As described above, according to the present invention, it is suitable as a positive resist for fine processing having a fineness of 1 μm or less, which is excellent in sensitivity, resolution and pattern shape.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Takeka Kato 1-2-1 Yokou, Kawasaki-ku, Kawasaki-shi, Kanagawa Nihon Zeon Co., Ltd.

Claims (2)

[Claims] 1. A positive resist composition comprising an alkali-soluble phenol resin, a quinonediazide sulfonic acid ester-based photosensitizer, and a phenol compound having a structural unit represented by the following general formula (I). Embedded image (In the formula, R1 to R3 are each independently a hydrogen atom, a hydroxyl group, a halogen atom, a substitutable alkyl group, a substitutable cycloalkyl group, a substitutable alkenyl group, a substitutable alkoxy group, or a substitutable aryl group. To R11 are independently a hydrogen atom, a substitutable alkyl group, a substitutable cycloalkyl group, a substitutable alkenyl group, or a substitutable aryl group.) 2. The positive resist composition according to claim 1, wherein the phenol compound has a polystyrene reduced weight average molecular weight of 2,000 or less in a GPC pattern using a UV254 nm detector. [0001]