JPH08292565A - Positive type resist composition - Google Patents

Abstract

PURPOSE: To improve sensitivity, the rate of a residual film, resolution, etc., as a positive type resist compsn. for fine working by incorporating alkali-soluble phenolic resin, a quinonediazidosulfonic ester type photosensitive agent and a specified phenolic compd. CONSTITUTION: This resist compsn. contains alkali-soluble phenolic resin, a quinonediazidosulfonic ester type photosensitive agent and a phenolic compd. having structural units represented by the formula, wherein each of R1 -R4 is H, hydroxyl, halogen, substitutable alkyl, substitutable cycloalkyl, substitutable alkenyl, substitutable alkoxy or substitutable aryl, at least one of R1 -R4 is hydroxyl and (n) is a positive integer. The alkali-soluble phenolic resin is, e.g. novolak type phenolic resin as a condensation reaction product of phenol with aldehyde. An ester compd. used as the photosensitive agent is, e.g., 1,2- benzoquinonediazido-4-sulfonic ester.

Description

Detailed Description of the Invention

[0001]

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.

[0002]

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 ratio, resolution, heat resistance and storage stability.
Further improvement in performance is desired. In particular, in forming a fine pattern of 0.5 μm or less, it is necessary to more strictly control the resist size, and a positive resist composition having a small so-called “exposure margin” when the exposure amount fluctuates or when the exposure light is defocused. Has been strongly demanded. From such a point of view, it has been proposed to use various phenol compounds (JP-A-3-
No. 200252, JP-A-4-122938, JP-A-5
No. 127,374, JP-A-5-232697). 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.

[0004]

Under the above-mentioned conventional techniques, the inventors of the present invention have diligently studied to solve the above problems, and as a result, by using a specific phenol compound, high resist characteristics can be obtained. The inventors have found that this can be achieved, and have completed the present invention.

[0005]

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

Embedded image (In the formula (I), R _{1 to} R ₄ 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, a substitutable aryl group. At least one of R _{1 to} R ₄ is a hydroxyl group, and n is a positive integer.) The present invention is described in detail below.

[Resist Composition] (A) Alkali-Soluble Phenolic Resin In the present invention, the alkali-soluble phenolic resin (a)
Can be used alone or in combination of two or more. Specific examples of the alkali-soluble phenol resin (a) include condensation reaction products of phenols and aldehydes, condensation reaction products of phenols and ketones, vinylphenol-based polymers, isopropenylphenol-based polymers. The hydrogenation reaction products of these phenolic resins and the like can be combined and used in combination, and novolac-based phenolic resins obtained by the condensation reaction of phenols and aldehydes are preferred examples.

Specific examples of the phenols used here include phenol, o-cresol, m-cresol and 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-methoxyphenol, 3-methoxyphenol, 2-propylphenol, 3-propylphenol, 4 Examples include-propylphenol, 2-isopropylphenol, 3-isopropylphenol, 4-isopropylphenol, 2-methoxy-5-methylphenol, 2-t-butyl-5-methylphenol, thymol and isothymol. Of these, o-cresol, m-cresol,
p-cresol, 2,3-dimethylphenol, 2,5
-Dimethylphenol, 3,4-dimethylphenol,
Preferred examples are 3,5-dimethylphenol, 2,3,5-trimethylphenol, 3,4,5-trimethylphenol and the like. These compounds may be used alone or in combination of two or more.

Specific examples of 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-methylbenzaldehyde, m-methylbenzaldehyde, p-methylbenzaldehyde,
Examples include p-ethylbenzaldehyde, pn-butylbenzaldehyde, and terephthalaldehyde. 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, acetophenone, o-hydroxyacetophenone,
Examples include m-hydroxyacetophenone, p-hydroxyacetophenone, 2,4-dihydroxyacetophenone, 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 phenolic resin used in the present invention
The polystyrene-converted weight average molecular weight by C (hereinafter sometimes referred to as the average molecular weight) is usually 2,000 to 25,
000, preferably 3,500 to 20,000.
If the average molecular weight is less than 3,500, 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 quinone diazide sulfonic acid ester of a polyhydroxy compound is prepared by converting a quinone diazide sulfonic acid compound into a quinone diazide sulfonic acid halide according to a conventional method, and then using sodium carbonate, sodium hydrogen carbonate or sodium hydroxide in a solvent such as acetone, dioxane or tetrahydrofuran. And inorganic bases such as potassium hydroxide, or trimethylamine, triethylamine, tripropylamine, diisopropylamine, tributylamine,
Pyrrolidine, piperidine, piperazine, morpholine, pyridine, dicyclohexylamine, 1,5-diazabicyclo [4.3.0] non-5-ene, 1,8-diazabicyclo [5.4.0] undec-7-ene, etc. By reacting a quinonediazidesulfonic acid halide with a polyhydroxy compound in the presence of an organic base, the quinonediazidesulfonic acid ester-based photosensitizer used in the present invention can be obtained.

The hydroxy compound used here is a known one having a phenol group, and specific examples include 2,3,4-trihydroxybenzophenone,
2,4,4'-trihydroxybenzophenone, 2,
3,4,4'-tetrahydroxybenzophenone, 2,
4,2 ', 4'-tetrahydroxybenzophenone,
Polyhydroxybenzophenones such as 2,3,4,2 ′, 4′-pentahydroxybenzophenone; gallic acid esters such as methyl gallate, ethyl gallate and propyl gallate; 2,2-bis (4-hydroxyphenyl) )
Propane, polyhydroxybisphenylalkanes such as 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-methoxy Polyhydroxytrisphenylalkanes such as phenylmethane;
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 phenols such as 2-methylresorcin, 4,6-bis (4-hydroxy-3-methylbenzyl) -2-methylresorcin and formaldehyde, phenol represented by the following general formula (II) and formaldehyde And a novolac resin.

Embedded image (In the formula (II), R ₅ and R ₆ are independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R _{7 to} R ₁₀ are independently an alkyl group having 1 to 4 carbon atoms. )

In the photosensitizer used in the present invention, the ratio of esterification of the 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).
It is preferably 3 to 50 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 In the present invention, the phenol compound as a modifier of the positive resist has a structural unit represented by the above formula (I) (hereinafter referred to as phenol compound (c)). Yes) is used. Such a compound can be obtained by subjecting phenols and dicyclopentadiene to an addition reaction in the presence of an acid catalyst. The phenols used as the raw material of the phenol compound (c) are not particularly limited and known ones can be used, but preferable examples include phenol, o-cresol, m-cresol and 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 -Isopropylphenol, 2-methoxy-5-methylphenol, 2-t-butyl-5-methylphenol, pyrogallol, thymol, isothymol and the like can be mentioned. These compounds may be used alone or in combination of two or more.

Dicyclopentadiene is a dimer of cyclopentadiene and has two isomers, an endo isomer and an exo isomer. However, dicyclopentadiene used as a raw material of the resin used in the present invention has no isomer. May be
It may also be a mixture of two isomers. When a mixture of isomers is used, the ratio of isomers is not particularly limited.

Further, as the phenol compound (c),
In addition to phenols and dicyclopentadiene,
An aldehyde or a ketone used as a raw material of a novolak resin may be allowed to react with each other to be used. Formaldehyde (formalin) is preferable as the aldehydes. When using aldehydes and ketones together, the usage rate of dicyclopentadiene is
20 parts by weight or more, preferably 5 parts by weight of the total amount of 100 parts by weight of aldehydes, ketones and dicyclopentadiene.
It is 0 part by weight or more, and more preferably 70 parts by weight or more.

Specific examples of the phenol compound (c) include those shown in Tables 1 and 2. Tables 2 and 3
R _{1 to} R _{4 in the} inside correspond to the formula (I). The phenol compound (c) contains at least one structural unit represented by the formula (I).

[0021]

[Table 1]

[Table 2]

The polystyrene-reduced weight average molecular weight (average molecular weight) of the phenol compound (c) used in the present invention by GPC using a UV 254 nm detector is
The alkali-soluble phenol resin can be arbitrarily selected depending on the type and average molecular weight, and is usually 2,000.
It is less than 1,500 or less. Also, GPC
In the chart, the portion having an average molecular weight of 2,000 or more is usually 40% or less, preferably 30% or less.

As a method for adjusting the average molecular weight of the compound to a desired range, the same method as the method for controlling the molecular weight and the molecular weight distribution of the alkali-soluble phenol resin can be mentioned.

(D) Additive In the present invention, a phenol compound other than the above-mentioned phenol compound (c) (hereinafter sometimes referred to as other phenol compound) can be used as an additive. Thereby, higher resist characteristics may be obtained in some cases.

As the other phenol compounds, those generally added to the positive resist composition can be used, and specific examples thereof include p-phenylphenol and p-phenylphenol.
-Monophenols such as isopropylphenol; biphenol, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxybenzophenone, bisphenol A (manufactured by Honshu Chemical Industry Co., Ltd.), bisphenol C (manufactured by 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 ( Bisphenols such as 4-hydroxyphenyl) fluorene, 1,1-bis (5-methyl-2-hydroxyphenyl) methane and 3,5-dimethyl-4-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)
Trisphenols such as -4-methylphenol, trisphenol-PA (manufactured by Honshu Chemical Industry Co., Ltd.), trisphenol-TC (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', α'-tetrakis (3-methyl -4-hydroxyphenyl) -3-
Examples include tetrakisphenols such as xylene, α, α, α ′, α′-tetrakis (3-methyl-4-hydroxyphenyl) -4-xylene. Of these, trisphenols and tetrakisphenols are particularly preferable examples.

The amount of addition of these other phenol compounds is
Alkali-soluble phenolic resin composition, average molecular weight, molecular weight distribution, type and amount of additives, phenolic compound (c)
The total amount of phenolic compounds (that is, the phenolic compound amount itself when the phenolic compound (c) is used alone, or the phenolic compound (c) and other phenolic compounds when used in combination with other phenol compounds Is 100 parts by weight of the alkali-soluble phenol resin, the upper limit is usually 100 parts by weight, preferably 60 parts by weight, more preferably 40 parts by weight, the lower limit is usually 3 parts by weight. , Preferably 5 parts by weight,
It is more preferably 10 parts by weight. When the phenol compound (c) is used in combination with another phenol compound, the ratio of both is usually 900 parts by weight or less, preferably 500 parts by weight, relative to 100 parts by weight of the phenol compound (c). Hereafter, it is more preferably 100 parts by weight or less.

The positive resist composition of the present invention is usually used by dissolving it in a solvent 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,
Esters such as methyl propionate, ethyl propionate, methyl butyrate, 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 glycols such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether; diethylene glycol monomethyl ether,
Diethylene glycols such as diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether; halogenated hydrocarbons such as trichloroethylene; toluene,
Aromatic hydrocarbons such as xylene; polar solvents such as dimethylacetamide, dimethylformamide, N-methylacetamide, etc. may be mentioned, and these may be used alone or in admixture of two or more. These solvents are used in an amount ratio sufficient to uniformly dissolve the above (A) to (C).

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.

Further, the positive resist composition of the present invention may optionally contain compatible additives such as a surfactant, a storage stabilizer, a sensitizer, an anti-striation agent and a plasticizer. be able to.

Examples of the surfactant include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether; polyoxyethylene octyl phenyl ether, polyoxyethylene nonylphenol ether. Polyoxyethylene aryl ethers such as; polyethylene glycol dialkyl esters such as polyethylene glycol dilaurate, ethylene glycol distearate; F-top EF3
01, EF303, EF352 (manufactured by Shin-Akita Kasei Co., Ltd.), Megafax F171, F172, F173, F177
(Manufactured by Dainippon Ink and Chemicals), Fluorard FC430, FC4
31 (Sumitomo 3M), Asahi Guard AG71
0, Surflon S-382, SC-101, SC-1
02, SC-103, SC-104, SC-105, S
Fluorosurfactants such as C-106 (manufactured by Asahi Glass Co., Ltd.); 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.

[Developer] In the resist composition of the present invention, an alkali aqueous solution is usually used as an alkali developer, and specific examples thereof include an aqueous solution of an inorganic alkali such as sodium hydroxide, potassium hydroxide, sodium silicate and ammonia. An aqueous solution of primary amines such as ethylamine and propylamine; an aqueous solution of secondary amines such as diethylamine and dipropylamine; an aqueous solution of tertiary amines such as trimethylamine and triethylamine; alcohol amines such as diethylethanolamine and triethanolamine Aqueous solution of tetramethylammonium hydroxide, tetraethylammonium hydroxide, trimethylhydroxymethylammonium hydroxide, triethylhydroxymethylammonium hydroxide, trimethylhydroxyethyl Such as an aqueous solution of quaternary ammonium hydroxide such as mode onium hydroxide 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.

[Pattern formation] A resist film may 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. it can. Spin coating is particularly recommended as the coating method at this time. The exposure sources used in the exposure for forming the pattern on the resist film thus obtained are ultraviolet rays, far ultraviolet rays, KrF excimer laser light, X-rays,
An electron beam source such as an electron beam may be used. 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 for carrying out 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 one or more phenol compounds. A phenol compound other than the phenol compound having the structural unit represented by formula (I) is selected from the group consisting of trisphenols and tetrakisphenols.
A positive resist composition comprising at least one type of phenol compound. 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 100 parts by weight with respect to 100 parts by weight of the alkali-soluble phenol resin, and the upper limit is 5 parts by weight. 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 upper limit of the phenol compound is 60 parts by weight and the lower limit thereof is 5 parts by weight with respect to 100 parts by weight of the alkali-soluble phenol resin. The positive resist composition containing.

[0034]

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 Novolac Resin A-2 To 380 g of the novolak resin obtained in Synthesis Example 1, 360 g of ethyl cellosolve acetate was added and dissolved. A dropping funnel was attached to the flask, and 950 g of toluene was dropped from the dropping funnel while the temperature was controlled at 80 to 85 ° C.
Heated at 0 ° 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 by decantation, 570 g of ethyl lactate was added,
The residual toluene was removed by heating to 100 ° C. at 100 mmHg to obtain an ethyl lactate solution of novolak resin A-2.
The polystyrene-reduced weight average molecular weight (Mw) of this novolak resin measured by GPC was 9,800.

(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 novolak resin A-4 To 380 g of the novolak resin obtained in Synthesis Example 3, 3800 g of toluene was 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.
_Five= R₆= H, R₇= R₈ = R₉= R_Ten= CH₃The compound that is
1, 2, as a quinonediazide sulfonic acid compound
Of naphthoquinonediazide-5-sulfonic acid chloride
In addition to using the mol% corresponding to the esterification rate of 70%
Is a quinonediazide sulfonic acid prepared in the same manner as in Synthesis Example 5.
Ester type photosensitizer B-2 was obtained.

(Synthesis Examples 7 to 9) Phenol compound (c-
1) to (c-3) acquisition Mitsui Toatsu Chemicals' dicyclopentadiene phenol resin "DPR-3000", "DPR-5000" or "DPR-5210" is ethyl cellosolve acetate as a good solvent and toluene as a poor solvent. Was used to carry out the separation operation. Dicyclopentadiene phenol resin "DPR
Although "-3000" and "DPR-5000" have different molecular weight distributions, both are copolymers of dicyclopentadiene and phenol. Dicyclopentadiene "D
PR5210 "is a copolymer of dicyclopentadiene, formaldehyde (or formalin), and phenol. As a result of the above fractionation operation, three types of phenol compounds c-1 having different polystyrene-equivalent weight average molecular weights in the GPC pattern using the UV254 nm detector were used.
(Mw = 750), c-2 (Mw = 1,200) and c-3 (Mw = 1,800) were obtained.

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 0.50 μm 1: 1 line & space The exposure energy amount that can be formed according to the design dimension is the 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 12 and Comparative Examples 1 and 2) Resins shown in Table 3, 30 parts by weight of a photosensitizer, a phenol compound (c) and additives were dissolved in ethyl lactate to give 1.17 μm.
The amount of solvent blended was adjusted so that it could be applied to a film thickness of. These solvents were filtered with a 0.1 μm Teflon filter (polytetrafluoroethylene filter) to prepare resist solutions R1 to R10. The resist solution was applied onto a silicon wafer with a coater and prebaked at 90 ° C. for 90 seconds to form a resist film having a thickness of 1.17 μm. This wafer is i-line stepper NSR1755i7
After exposure was performed using A (manufactured by Nikon; NA = 0.50) and a test reticle while changing the exposure time,
Post-exposure bake at 110 ° C. for 60 seconds (Post Expo
Sure baking) was performed. Next is 2.38%
23 with an aqueous solution of tetramethylammonium hydroxide
It was developed by a paddle method at 1 ° C. for 1 minute 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.
The results are shown in Table 3.

[0044]

[Table 3]

As a result, it was found that when the phenol compound having the phenol compound having the structural unit represented by the general formula (I) is contained, the sensitivity, the residual film ratio, the resolution and the pattern shape are improved. .

[0046]

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

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

Claims (1)

[Claims] 1. An alkali-soluble phenolic resin (a),
A positive resist composition containing a quinonediazide sulfonic acid ester-based photosensitizer (b) and a phenol compound (c) having a structural unit represented by the following general formula (I). Embedded image (In the formula (I), R _{1 to} R ₄ 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, a substitutable aryl group. (At least one of R _{1 to} R ₄ is a hydroxyl group, and n is a positive integer.)