JPH08220750A - Positive type resist composition - Google Patents

Abstract

PURPOSE: To improve sensitivity and resolution and to obtain a superior pattern shape by incorporating alkali=soluble phenolic resin having specified structural units and a quinonediazidesulfonic ester photosensitive agent. CONSTITUTION: This resist compsn. contains alkali-soluble phenolic resin having structural units represented by the formula and a quinonediazidesulfonic ester photosensitive agent. In the formula, 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. An ester compd. used as the photosensitive agent is, e.g. 1,2- benzoquinonediazide-4-sulfonic ester of a polyhydroxy compd.

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 alkali-soluble phenolic resins (JP-A-3-236053, JP-A-5-173326, JP-A-5-232696, etc.). 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 such a conventional technique, the inventors of the present invention have conducted extensive studies to solve the above-mentioned problems, and as a result, use an alkali-soluble phenol resin (a) having a specific structural unit. As a result, it was found that high resist characteristics can be obtained, and the present invention has been completed.

[0006]

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

Embedded image (In the formula, R1 to R4 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. At least one of R4 is a hydroxyl group, and n is a positive integer.)

The present invention will be described in detail below. (A) Alkali-Soluble Phenolic Resin The alkali-soluble phenolic resin used in the present invention is particularly preferably one having a structural unit represented by the above general formula (I) (hereinafter sometimes referred to as resin (a)). Not limited. Specific examples of such resins are shown in Table 1.
To (a-1) to (a-16) and the like shown in 2 to 2. R1 to R4 in the table correspond to the general formula (I).

[0008]

[Table 1]

[0009]

[Table 2]

Among these compounds, particularly preferred are a-1, a-2, a-5, a-6, a-7 and a-11.
Is.

The resin (a) can be obtained by addition reaction of dicyclopentadiene and phenols in the presence of an acid catalyst. The phenols used here are
Known compounds can be used without particular limitation, but preferred examples include phenol, o-cresol, m-cresol, p-cresol, 2,3-dimethylphenol, 2,5-dimethylphenol, and 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-isopropyl Phenol, 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, endo and exo,
The dicyclopentadiene used as the raw material of the resin used in the present invention may be any isomer or a mixture of two isomers. When a mixture of isomers is used, the ratio of isomers is not particularly limited.

U of the resin (a) used in the present invention
Polystyrene-equivalent weight average molecular weight by GPC using V254 nm detector (hereinafter, simply referred to as average molecular weight)
Has an upper limit of 15,000 or less, preferably 10,0
It is 00 or less. The lower limit is 2,000 or more, preferably 3,000 or more. The average molecular weight of 1,000
The following portion is 20% or less, preferably 15% or less. When the average molecular weight is 10,000 or more, the pattern shape, developability and sensitivity tend to be deteriorated, and particularly, it is 15,0
If it exceeds 00, it is not practical. The average molecular weight of 3,0
If it is less than 00, the pattern shape, developability and resolution are deteriorated, and if it is less than 2,000, it is not practical. further,
15% of the average molecular weight of 1,000 or less by GPC
If it is more than 20%, the pattern shape, developability and resolution tend to deteriorate, and if it is 20% or more, it is not practical.

In order to control the average molecular weight of the resin (a) to a desired range, it 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.

In the present invention, in addition to the resin (a) described above as the alkali-soluble phenol resin, the resin (a)
Other than the above, one or more kinds of alkali-soluble phenol resins (hereinafter sometimes referred to as other resins) may be mixed and used.

When another resin is used in combination, the amount of the other resin can be arbitrarily selected, and the preferable amount varies depending on the average molecular weight of the resin (a), but usually the resin (a):
The ratio of other resins is 5:95 to 95: 5 (parts by weight), preferably 20:80 to 80:20 (parts by weight). In particular, even if the average molecular weight of the resin (a) is within the above range, if the average molecular weight is relatively low (usually about 4,500 or less), the ratio of the resin (a) to the other resin is a):
When the other resin is used together in an amount in the range of 5:95 to 50:50 (parts by weight), the resist characteristics are dramatically improved.

Specific examples of other resins used in combination include, for example, condensation reaction products of phenols and aldehydes, vinylphenol-based polymers, isopropenylphenol-based polymers, hydrogenation reactions of these phenolic resins. Products 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 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.
These condensation reaction products can be obtained by a conventional method, for example, by reacting phenols and aldehydes in the presence of an acidic catalyst.

The vinylphenol-based polymer is selected from a homopolymer of vinylphenol and a copolymer of vinylphenol and a component copolymerizable with vinylphenol. The isopropenylphenol-based 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.

Regarding the other resins used in combination,
Like the resin (a), it can be used by controlling the molecular weight and the molecular weight distribution by known means. The average molecular weight of other resins is usually 2,000 to 25,000.
It is 0, 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.

(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 prepared by converting a quinonediazidesulfonic acid compound into a quinonediazidesulfonic 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 thereof 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 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, R5 and R6 are independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R7 to R10 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 sensitizers used in the present invention may be used alone or in combination 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 In the present invention, a low molecular weight phenol compound is used as an optional component for the purpose of promoting alkali solubility of the resist composition of the present invention and improving sensitivity, residual film ratio, resolution and heat resistance. Can be added. Specific examples of the low molecular weight phenol compound include p-phenylphenol,
Monophenols such as p-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 (Made by Honshu Chemical Industry Co., Ltd.), bisphenol F (made by Honshu Chemical Industry Co., Ltd.), bisphenol AP (made by 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 the (C) phenol compound added varies depending on the composition of the alkali-soluble phenol resin, the molecular weight, the molecular weight distribution, and the kind and amount of other additives.
With respect to 0 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. .

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, 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 optionally contain compatible additives such as a surfactant, a storage stabilizer, a sensitizer, an anti-striation agent and a plasticizer. it can.

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.

In the resist composition of the present invention, an alkaline aqueous solution is usually used as an alkaline developing solution. Specific examples thereof include aqueous solutions of inorganic alkali such as sodium hydroxide, potassium hydroxide, sodium silicate and ammonia; ethylamine and propyl. Aqueous solutions of primary amines such as amines;
Aqueous solutions of secondary amines such as diethylamine and dipropylamine; aqueous solutions of tertiary amines such as trimethylamine and triethylamine; aqueous solutions of alcohol amines such as diethylethanolamine and triethanolamine; tetramethylammonium hydroxide, tetraethylammonium hydroxide, Examples thereof include aqueous solutions of quaternary ammonium hydroxide such as trimethylhydroxymethylammonium hydroxide, triethylhydroxymethylammonium hydroxide and trimethylhydroxyethylammonium hydroxide. 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 for carrying out the present invention are shown below, but the present invention is not limited thereto. In a positive resist composition containing (A) an alkali-soluble phenol resin and (B) a quinonediazide sulfonic acid ester-based photosensitizer, the (A) alkali-soluble phenol resin has a structural unit represented by the general formula (I). A positive resist composition comprising an alkali-soluble phenolic resin and one or more other alkali-soluble phenolic resin other than the formula resin. In a positive resist composition containing (A) an alkali-soluble phenol resin and (B) a quinonediazide sulfonic acid ester-based photosensitizer, (A) the alkali-soluble phenol resin is a polystyrene-converted weight average molecular weight measured by GPC using a UV 254 nm detector. Is from 15,000
A positive resist composition, which is an alkali-soluble phenol resin having a structural unit represented by the general formula (I) of 2,000. In a positive resist composition containing (A) an alkali-soluble phenol resin and (B) a quinonediazide sulfonic acid ester-based photosensitizer, (A) the alkali-soluble phenol resin is a polystyrene-converted weight average molecular weight measured by GPC using a UV 254 nm detector. Is 10,000-
A positive resist composition, which is an alkali-soluble phenol resin having a structural unit represented by the general formula (I) of 2,000. In a positive resist composition containing (A) an alkali-soluble phenol resin and (B) a quinonediazide sulfonic acid ester-based photosensitizer, (A) the alkali-soluble phenol resin is a polystyrene-converted weight average molecular weight measured by GPC using a UV 254 nm detector. Is from 15,000
A positive resist composition, which is an alkali-soluble phenol resin having a structural unit represented by the general formula (I) of 3,000. In a positive resist composition containing (A) an alkali-soluble phenol resin and (B) a quinonediazide sulfonic acid ester-based photosensitizer, (A) the alkali-soluble phenol resin is a polystyrene-converted weight average molecular weight measured by GPC using a UV 254 nm detector. Is 10,000-
A positive resist composition, which is an alkali-soluble phenol resin having a structural unit represented by the general formula (I) of 3,000. (A) Alkali-soluble phenolic resin containing an alkali-soluble phenolic resin having a structural unit represented by the general formula (I) and one or more other alkali-soluble phenolic resins other than the resin, (B) Quinonediazide sulfonic acid ester In a positive resist composition containing a photosensitizer, a resin having a weight average molecular weight of a resin having a structural unit represented by formula (I) in an alkali-soluble phenolic resin (A) is a resin in any of the above ranges. A positive resist composition, characterized in that (A) Alkali-soluble phenolic resin containing an alkali-soluble phenolic resin having a structural unit represented by the general formula (I) and one or more other alkali-soluble phenolic resins other than the resin, (B) Quinonediazide sulfonic acid ester In a positive resist composition containing a photosensitizer, (A) an alkali-soluble phenolic resin having the structural unit represented by the general formula (I) in the alkali-soluble phenolic resin and one or more other than the resin The positive resist composition is characterized in that the ratio (parts by weight) with respect to the alkali-soluble phenol resin is from 95: 5 to 5:95. (A) Alkali-soluble phenolic resin containing an alkali-soluble phenolic resin having a structural unit represented by the general formula (I) and one or more other alkali-soluble phenolic resins other than the resin, (B) Quinonediazide sulfonic acid ester In a positive resist composition containing a photosensitizer, the alkali-soluble phenolic resin having the structural unit represented by the general formula (I) in (A) alkali-soluble phenolic resin is measured by GPC using a UV 254 nm detector. The weight average molecular weight in terms of polystyrene is 2,000 to 4,500, and the ratio of the resin and one or more other alkali-soluble phenol resin other than the resin is in the range of 5:95 to 50:50 (parts by weight). And a positive resist composition.

[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) Acquisition of Resin a-1 Dicyclopentadiene phenol resin "DPR-5000", "DPR-3000" or "DPR-5210" manufactured by Mitsui Toatsu Chemicals, Inc. was used as a good solvent for ethyl cellosolve acetate, Using toluene as the poor solvent, fractionation was performed, and the polystyrene-converted weight average molecular weight (Mw) by GPC was 2,500, 4,500 and 6, respectively.
000 resins were obtained.

(Synthesis Example 2) Synthesis of Resin a-2 In a 2 liter flask equipped with a cooling pipe and a sales expansion device,
130 g of m-cresol, 87 g of p-cresol, 172 g of dicyclopentadiene and 1.6 oxalic acid dihydrate.
4 g was put and gradually heated to reach 98 ° C. in 30 minutes.
The reaction was carried out for 2 hours while maintaining the temperature at 95 to 100 ° C. While further raising the temperature to 180 ° C, reduce the pressure to 10 mmHg,
After removing unreacted monomer, return to room temperature and collect,
The resinous product was fractionated using ethyl cellosolve acetate as a good solvent and toluene as a poor solvent to obtain an alkali-soluble resin a-2. The polystyrene-reduced weight average molecular weight (Mw) of the obtained resin by GPC was 450.
It was 0.

(Synthesis Example 3) Resins a-5, a-6, a-7
And a-11 Synthesis of resin a- by the same operation as in Synthesis Example 2 except that resorcinol, 4-methylcatechol, pyrogallol, and 4-phenylphenol were used as phenol compounds, respectively.
5, a-6, a-7 and a-11 were obtained. The polystyrene-reduced weight average molecular weight (M
w) is 4500, 4500, 4500, 250 respectively
It was 0.

(Synthesis Example 4) Synthesis of Novolac Resin A-1 A 2 liter flask equipped with a cooling tube 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. When the polystyrene-converted weight average molecular weight of this novolak resin A-1 was measured by GPC,
It was 6000.

(Synthesis Example 5) Synthesis of Novolak Resin A-2 380 g of the novolak resin obtained in Synthesis Example 4 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 of this novolak resin measured by GPC was 9,800.

(Synthesis Example 6) Synthesis of Novolac Resin A-3 In a 2 liter flask equipped with a cooling tube 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 of this novolak resin A-3 was measured by GPC to find that it was 640.
It was 0.

(Synthesis Example 7) Synthesis of Novolac Resin A-4 380 g of the novolak resin obtained in Synthesis Example 6 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-reduced weight average molecular weight of this novolak resin measured by GPC was 9,800.

Synthesis Example 8 Synthesis of Photosensitizer B-1 The novolac resin A-1 obtained in Synthesis Example 4 was used as the polyhydroxy compound, and 1,2-naphthoquinonediazide-5-sulfonic acid was used as the quinonediazidesulfonic acid compound. Chloride (the amount is mol% corresponding to an esterification rate of 40%) was dissolved in acetone to obtain a 10% solution. 20
While controlling the temperature 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. It 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 precipitated solid content was filtered, washed with ion-exchanged water, and dried to obtain a quinonediazide sulfonic acid ester-based photosensitizer B-1.

(Synthesis Example 9) Synthesis of Photosensitizer B-2 R represented by the general formula (II) as a polyhydroxy compound
5 = R6 = H, R7 = R8 = R9 = R10 = with CH _3, compound, 1,2 as quinonediazide sulfonic compound
-A quinonediazide sulfonic acid ester-based photosensitizer B-2 was obtained in the same manner as in Synthesis Example 8 except that the amount of naphthoquinonediazide-5-sulfonic acid chloride was changed to a mol% corresponding to an esterification rate of 70%.

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 12 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, and the amount of the solvent was adjusted so as to be applied to a film thickness of 1.17 μm. did. These solvents were filtered with a 0.1 μm Teflon filter (polytetrafluoroethylene filter) to prepare a resist solution.

The resist solution was coated on 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 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. The results are shown in Table 3.

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[Table 3]

As a result, it was found that when the resin having the structural unit represented by the general formula (I) was used as the resin, the sensitivity, the residual film rate, the resolution, the pattern shape and the like were improved.

[0049]

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.

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

Claims (1)

[Claims] 1. A positive resist composition comprising an alkali-soluble phenol resin (a) having a structural unit represented by the following general formula (I) and a quinonediazide sulfonic acid ester-based photosensitizer (b). . Embedded image (In the formula, R1 to R4 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. At least one of R4 is a hydroxyl group, and n is a positive integer.)