JPH0345825B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a positive resist composition useful as a resist for microfabrication. In recent years, there has been remarkable progress in semiconductor integrated circuit manufacturing technology, and the resists used for manufacturing highly integrated semiconductor integrated circuits have changed from cyclized isoprene rubber-based negative resists, which have a large drop in resolution due to swelling, to alkaline-soluble resins, which have less swelling. There is a shift toward positive resists based on combinations of 1,2-naphthoquinonediazide and 1,2-naphthoquinonediazide compounds. However, even if a positive resist is used, side etching occurs when wet etching is performed, making it difficult to increase the degree of integration of semiconductor integrated circuits. This side etching phenomenon occurs because wet etching progresses isotropically.
This phenomenon is unavoidable as long as wet etching is used. Therefore, in recent years, reactive ion etching, which sputters charged ions perpendicularly to the surface to be etched to perform anisotropic etching, has been developed.
Dry etching, also known as ion milling, is attracting attention and is already at the stage of practical application.
However, this method generates a large amount of heat because charged particles are spattered onto the resist surface. Therefore, a resist to which this dry etching can be applied is required to have excellent dry etching resistance and good heat resistance. An object of the present invention is to improve the above-mentioned drawbacks of the prior art and to provide a positive resist composition having high resolution and excellent heat resistance, dry etching resistance, and film retention rate. The present invention has a repeating structural unit represented by the following general formula (A) of 20 to 95%, a repeating structural unit represented by the following general formula (B), and/or a repeating structural unit represented by the following general formula (C). The present invention provides a positive resist composition comprising an alkali-soluble resin having a proportion of 5 to 80% and a 1,2-quinonediazide compound. General formula (A) General formula (B) General formula (C) (In each formula, R ¹ to ^{R 4} are hydrogen atoms, R ⁵ is an alkyl group having 1 to 4 carbon atoms, or 1,
2-quinonediazide group, R ⁶ is a hydrogen atom or a methyl group. ) Hereinafter, the present invention will be explained in detail. The positive resist composition according to the present invention contains a repeating structural unit represented by the general formula (A), a repeating structural unit represented by the general formula (B), and/or a repeating structural unit represented by the general formula (C). It consists of an alkali-soluble resin, a 1,2-quinonediazide compound, and additives added as necessary, and is used after being dissolved in an organic solvent. In the present invention, the alkali-soluble resin;
The composition ratio with the 1,2-quinonediazide compound is generally based on 100 parts by weight of the alkali-soluble resin.
5 to 100 parts by weight of 1,2-quinonediazide compound,
Preferably it is 10 to 50 parts by weight. If the composition ratio of the 1,2-quinonediazide compound is less than 5 parts by weight, the amount of carboxylic acid produced by absorbing light will be small, resulting in a difference in the solubility of the resist coating before and after light irradiation in a developer consisting of an alkaline aqueous solution. is small, making patterning difficult. If the amount exceeds 100 parts by weight, the added 1,2-
Since most of the quinonediazide compound remains in its powder form, the insolubilization effect in alkaline aqueous solutions is too high, making it difficult to develop the resist coating, and the ability to form a coating and the mechanical properties of the coating decrease. There is a tendency to In the alkali-soluble resin used in the present invention, the proportion of repeating structural units represented by general formula (A) is 20 to 95%, preferably 30 to 95% of all repeating structural units, and the proportion of repeating structural units represented by general formula (B) is 20 to 95%, preferably 30 to 95%, and The proportion of the repeating structural units represented by and/or the repeating structural units represented by general formula (C) is 5 to 5% of the total repeating structural units.
80%, preferably 5-70%. Repeating structural unit represented by general formula (B) and/
Alternatively, if the proportion of repeating structural units represented by the general formula (C) is less than 5%, for example, in the case of a homopolymer of nuclear-substituted hydroxystyrene, the solubility in a developer consisting of an alkaline aqueous solution will be excessive, resulting in a decrease in the residual film rate. On the other hand, if it exceeds 80%, the solubility in a developing solution consisting of an alkaline aqueous solution becomes too low, resulting in an extreme decrease in developability. The alkali-soluble resin has general formula (A), general It may contain repeating structural units other than those represented by formula (B) and general formula (C). Such repeating structural units include, for example, styrene units,
Styrenic units such as α-methylstyrene units, (meth)acrylate units such as methyl (meth)acrylate units, ethyl (meth)acrylate units, 2-hydroxyethyl (meth)acrylate units, maleic anhydride units, ( Meta)
Examples include acrylic acid units. Further, the number average molecular weight of the alkali-soluble resin is not particularly limited as long as it maintains alkali solubility, but is preferably 1,000 to 100,000, particularly preferably 2,000 to 50,000. The alkali-soluble resin has the following general formula, for example:
It can be obtained by esterifying a polymer of a hydroxystyrene derivative represented by (D) using a chloride represented by the following general formula (E) or general formula (F). General formula (D) General formula (E) General formula (F) (In the formula, R ¹ to ^{R 6} are the general formula (A) and the general formula (B)
Or it is the same as that in general formula (C). ) Hydroxystyrene derivatives represented by the above general formula (D) include, for example, o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, α-methyl-o-hydroxystyrene,
Examples include α-methyl-m-hydroxystyrene and α-methyl-p-hydroxystyrene. Examples of the chloride represented by the above general formula (E) include acetyl chloride, propionyl chloride, butyryl chloride, and 1,2-naphthoquinonediazide-5 chloride.
-carbonyl, 1,2-naphthoquinonediazide-4-carbonyl chloride, 1,2-benzoquinonediazide-4-carbonyl chloride, and the like. Examples of the chloride represented by the above general formula (F) include ethylsulfonyl chloride, butylsulfonyl chloride, 1,2-naphthoquinonediazide-5-sulfonyl chloride, -1,2-naphthoquinonediazide-4-sulfonyl chloride, and - Examples include 1,2-benzoquinonediazide-4-sulfonyl. In this esterification, generally basic organic solvents such as pyridine and N-methylpyrrolidone, alkali metals such as sodium hydroxide and potassium hydroxide, and organic amines such as trimethylamine can be used as catalysts. The reaction temperature in esterification is generally 10 to 60°C, preferably
10-40℃, reaction time 15 minutes-6 hours, preferably
The duration is 30 minutes to 4 hours. The polymer of the hydroxystyrene derivative represented by the general formula (D) can be obtained, for example, by the following methods (i) to (iv). (i) “Journal of Polymer Science”
A-1, Volume 7, pages 2175-2184 and 2405
~2410 pages (1969), Japanese Patent Application Publication No. 57-44607,
A method of cationically polymerizing a hydroxystyrene derivative in the presence of a cationic polymerization catalyst such as boron trifluoride ethyl ether or an organic carboxylic acid, as described in Publications No. 57-44608 and No. 57-44609. (ii) As described in "Journal of Organ Chemistry" Vol. 24, pp. 1345-1347 (1959), hydroxystyrene derivatives are used as radical polymerization initiators such as azobisisobutyronitrile, A method of radical polymerization using ionizing radiation, light, etc. (iii) “Journal of Polymer Science,
Polymer Chemistry Edition” No. 12
Vol., pp. 2017-2025 (1974), an azo compound such as azobisisobutyronitrile, a peroxide such as benzoyl peroxide, lauroyl peroxide, etc. using an acetylated hydroxystyrene derivative as a radical polymerization initiator. A method in which the acetyl groups of the polymer are completely hydrolyzed using an acid such as hydrazine, hydrogen chloride, or acetic acid, or a base such as potassium hydroxide or sodium hydroxide after radical polymerization using ionizing radiation, light, etc. (iv) After silylating the hydroxystyrene derivative with a silylation reagent such as t-butylene dimethylsilyl chloride or phenyldimethylsilyl chloride, it is converted into n-butyllithium or sec-butyllithium in an organic solvent such as tetrahydrofuran, benzene, or toluene. , a method of anionic polymerization using an anionic polymerization catalyst such as sodium naphthalene or potassium naphthalene, followed by desilylation using hydrochloric acid, hydrofluoric acid, potassium fluoride, etc. The hydroxystyrene derivative represented by the general formula (D) can be obtained by hydrolyzing coumarin or coumarin substitutes, for example, as described in "Journal of Organ Chemistry", Vol. 23, pp. 544-599. A method for decarboxylating hydroxycinnamic acid obtained by
Gedogi) Volume 16, pages 1-20 (published in 1943),
"Chemical Analysis (Anrlen der Chemie)" Volume 413, No.
It can be obtained by the method described in pages 287-309 (published in 1919). Note that the method (iii) above
In this step, the alkali-soluble resin used in the present invention can be directly obtained by hydrolyzing only a portion of the acetyl groups of the polymer. The alkali-soluble resin is a novolak resin or resol resin synthesized from other alkali-soluble resins, such as aromatic hydroxy compounds such as phenol, cresol, xylenol, resorcinol, and hydroquinone, and aldehydes such as formaldehyde, acetaldehyde, and benzaldehyde, or these resins. For example, the modified resin may be used in combination with about 50 parts by weight or less, preferably about 40 parts by weight or less, based on 100 parts by weight of the above-mentioned alkali-soluble resin. Examples of the 1,2-quinonediazide compound used in the present invention include 1,2-benzoquinonediazide sulfonic acid ester, 1,2-naphthoquinonediazide sulfonic acid ester, 1,2-benzoquinonediazide sulfonic acid amide, and 1,2-naphthoquinonediazide sulfonic acid ester. Quinonediazide sulfonic acid amide, etc., and known 1,2-quinonediazide compounds can be used as they are. More specifically, J. Kosar, “Light-Sensitive Systems” 339-3352,
(1965), John Wiley & Sons (New
York) and “Photoresist” by WS De Forest.
50, (1975), Mc Graw Hill, lnc. (New York)
Examples include 1,2-quinonediazide compounds described in . That is, 1,2-benzoquinonediazide-4-sulfonic acid phenyl ester, di-(1'',2''-benzoquinonediazide-4''-sulfonyl)-4,4'-dihydroxybiphenyl, 1,
2-benzoquinonediazide-4-(N-ethyl-
N-β-naphthyl)-sulfonamide, 1,2-
Naphthoquinonediazide-5-sulfonic acid cyclohexyl ester, 1-(1',2'-naphthoquinonediazide-5'-sulfonyl)-3,5-dimethylpyrazole, 1,2-naphthoquinonediazide-5-
Sulfonic acid-4'-hydroxydiphenyl-4''-azo-β-naphthol ester, N,N-di-(1,
2-naphthoquinonediazide-5-sulfonyl)-
Aniline, 2-(1',2'-naphthoquinonediazide-5'-sulfonyloxy)-1-hydroxy-anthraquinone, 1,2-naphthoquinonediazide-
Condensate of 2 moles of 5-sulfonic acid chloride and 1 mole of 4,4'-diaminobenzophenone, 1,2-naphthoquinonediazide-5-sulfonic acid chloride 2
condensate of 1 mole of 4,4'-dihydroxy-1,1'-diphenylsulfone, 1 mole of 1,2-naphthoquinonediazide-5-sulfonic acid chloride and 1 mole of purpurogalin, 1,2 -naphthoquinone diazide-5-(N-dihydroabiethyl)-sulfonamide and the like can be exemplified. Also, Japanese Patent Publication No. 37-1953, Publication No. 37-3627, Publication No. 37-13109, Publication No. 40-26126, Publication No. 40-26126,
Publication No. 40-3801, Publication No. 45-5604, Publication No. 45-
Publication No. 27345, Publication No. 51-13013, Japanese Unexamined Patent Publication No. 1973-
Publication No. 96575, Publication No. 48-63802, Publication No. 48-63803
Publication No. 58-75149, etc.
1,2-quinonediazide compounds can also be used. Furthermore, the following general formula () General formula below () (In the general formulas () and (), a and b are the same or different, an integer of 3 or 4, l
and m are the same or different, 0 or an integer of 1 to 3, c is an integer of 1 to 4, n is 0 or an integer of 1 to 3, and (a-l), (b-m) and ( c-n) are all integers of 1 or more; R ₁ , R ₅ and R ₇ are the same or different; 1,2-naphthoquinonediazide-4-sulfonyl group, 1,2-naphthoquinonediazide-5-sulfonyl group or 1 ,2
-benzoquinonediazide-4-sulfonyl group,
R ₂ , R ₆ , R ₈ and R ₁₁ are the same or different, and are hydrogen atoms, halogen atoms, alkyl groups, aryl groups,
Aralkyl group, alkoxy group, cyano group or nitro group, R ₃ , R ₄ , R ₉ and R ₁₀ are the same or different and mean a hydrogen atom, alkyl group, aryl group or aralkyl group, R ₃ and R ₄ and R ₉ and R ₁₀ can form a ring with a carbon-carbon bond or an ether bond) The following general formula () (In the general formula (), n is an integer of 2 to 4,
l is 0 or an integer of 1 to 3, m is an integer of 1 to 4,
k is an integer from 1 to 4, and k+l+m=5,
R ₁ is 1,2-naphthoquinonediazide-4-sulfonyl group, 1,2-naphthoquinonediazide-5-
Sulfonyl group or 1,2-benzoquinonediazide-4-sulfonyl group, _R2 is hydrogen atom, halogen atom, alkyl group, aryl group, aralkyl group, alkoxy group, cyano group or nitro group, Z
means the residue of methane or an aromatic compound) The following general formula () Or the following general formula () (In general formulas () and (), a, b
and c are the same or different, integers from 1 to 4,
l, m and n are the same or different, 0 or 1
~3 integers, (a-l), (b-m) and (c-
n) is an integer of 1 or more, R ₁ , R ₂ and R ₅ are the same or different, and 1,2-naphthoquinonediazide-4
-sulfonyl group, 1,2-naphthoquinonediazide-5-sulfonyl group or 1,2-benzoquinonediazide-4-sulfonyl group, R ₃ , R ₄ and R ₆
are the same or different, hydrogen atom, halogen atom,
alkyl group, aryl group, aralkyl group, alkoxy group, cyano group or nitro group, R ₇ means an alkyl group, aryl group or aralkyl group, Z means an alkylene group or oxaalkylene group with or without a substituent) A 1,2-quinonediazide compound represented by can also be used. The 1,2-quinonediazide compound represented by the above general formula () is, for example, (2,3,4-trihydroxyphenyl)methane, 1,1-di(2,
3,4-trihydroxyphenyl)propane,
2,2-di(2,3,4-trihydroxyphenyl)propane, 1,1-di(2,3,4-trihydroxyphenyl)butane, 1,1-di(2,
3,4-trihydroxyphenyl)cyclohexane, 1,1-di(2,3,4-trihydroxyphenyl)-4-oxacyclohexane, di(2,
4,6-trihydroxyphenyl)methane, 1,
1-di(2,4,6-trihydroxyphenyl)
Propane, 2,2-di(2,4,6-trihydroxyphenyl)propane, 1,1-di(2,4,
6-trihydroxyphenyl)butane, 1,1-
Di(2,4,6-trihydroxyphenyl)cyclohexane, 1,1-di(2,4,6-trihydroxyphenyl)-4-oxacyclohexane,
Di(2,3,4-trihydroxy-5-bromophenyl)methane, 2,2-di(2,4,6-trihydroxy-3-chlorophenyl)propane, di(2,3,4-trihydroxy-5 -methylphenyl)methane, 2,2-di(2,4,6-trihydroxy-3-methylphenyl)propane, di(2,3,4-trihydroxy-5-cyanophenyl)methane, 2,2-di(2 , 4,6-trihydroxy-3-nitrophenyl)propane, di(1,2,3,4-tetrahydroxyphenyl)
Polyhydroxy compounds such as methane, 2,2-di(1,2,3,5-tetrahydroxyphenyl)propane and 1,2-naphthoquinonediazide-5-
It can be obtained by condensing sulfonyl chloride, 1,2-naphthoquinonediazide-4-sulfonyl chloride, or 1,2-benzoquinonediazide-4-sulfonyl chloride at an equivalent ratio of 0.125 to 1. The 1,2-quinonediazide compound represented by the above general formula () is, for example, 2,3,4-trihydroxydiphenylmethane, 2,4,6-trihydroxydiphenylmethane, 2,3,4-trihydroxy- 5-chlorodiphenylmethane, 2,4,
6-trihydroxy-3-bromodiphenylmethane, 2,3,4-trihydroxy-5-methyldiphenylmethane, 2,4,6-trihydroxy-
3-cyanodiphenylmethane, 2,3,4-trihydroxy-5-nitrodiphenylmethane, 2,
3,4-trihydroxy-4'-methyldiphenylmethane, 2,4,6-trihydroxy-4'-methyldiphenylmethane, 2,3,4-trihydroxy-4'-t-butyldiphenylmethane ,2,3,
4,5-tetrahydroxydiphenylmethane,
2,3,4,6-tetrahydroxydiphenylmethane, 2,5-dihydroxydiphenylmethane,
2,4-dihydroxydiphenylmethane, 2,4
-dihydroxy-4′-methyldiphenylmethane,
2,5-dihydroxy-4'-t-butyldiphenylmethane, 2-(2,3,4-trihydroxyphenyl)-2-phenylpropane, 2-(2,4,
6-trihydroxyphenyl)-2-phenylpropane, 2-(2,3,4-trihydroxy-5
-chlorophenyl)-2-phenylpropane, 2
-(2,3,4-trihydroxy-5-methylphenyl)-2-phenylpropane, 2-(2,4,
6-trihydroxy-3-cyanophenyl)-2
-Phenylpropane, 2-(2,3,4-trihydroxy-5-nitrophenyl)-2-phenylpropane, 2-(2,3,4-trihydroxyphenyl)-2-(p-tolyl) Propane, 2-(2,
4,6-trihydroxyphenyl)-2-(4-t
-butylphenyl)propane, 2-(2,3,4,
5-tetrahydroxyphenyl)-2-phenylpropane, 2-(2,3,4,6-tetrahydroxyphenyl)-2-phenylpropane, 2-
(2,5-dihydroxyphenyl)-2-phenylpropane, 2-(2,4-dihydroxyphenyl)
-2-phenylpropane, 2-(2,4-dihydroxyphenyl)-2-(p-tolyl)propane and other polyhydroxy compounds and 1,2-naphthoquinonediazide-5-sulfonyl chloride, 1,2-
It can be obtained by condensing naphthoquinonediazide-4-sulfonyl chloride or 1,2-benzoquinonediazide-4-sulfonyl chloride at an equivalent ratio of 0.25 to 1. Details of the 1,2-quinonediazide compound represented by the above general formula () or () are described in the applicant's patent application "Positive photosensitive resin composition" dated December 6, 1982. The 1,2-quinonediazide compound represented by the above general formula () is, for example, p-bis(4-hydroxybenzoyl)benzene, p-bis(2,5-
dihydroxybenzoyl)benzene, p-bis(2,3,4-trihydroxybenzoyl)benzene, m-bis(2,4,6-trihydroxybenzoyl)benzene, p-bis(4-hydroxy-3-chlorobenzoyl) Benzene, p-bis(2,3,4-trihydroxy-5-methylbenzoyl)benzene, p-bis(2,4,6-trihydroxy-3-nitrobenzoyl)benzene,
p-bis(2,3,4-trihydroxy-5-cyanobenzoyl)benzene, 1,3,5-tris(2,5-dihydroxybenzoyl)benzene,
1,2,3-tris(2,3,4-trihydroxybenzoyl)benzene, 1,2,4-tris(2,4,6-trihydroxybenzoyl)benzene, 1,2,4,5-tetrakis( 2, 3, 4
-trihydroxybenzoyl)benzene, α,
α'-bis(2,3,4-trihydroxybenzoyl)-p-xylene, α-α'-α'-tris(2,
Polyhydroxy compounds such as 3,4-trihydroxybenzoyl)mesitylene, 1,2-bis(2,3,4-trihydroxybenzoyl)naphthalene, and 1,2-naphthoquinonediazide-5-sulfonyl chloride, 1,2-naphtho It can be obtained by condensing quinonediazide-4-sulfonyl chloride or 1,2-benzoquinonediazide-4-sulfonyl chloride at an equivalent ratio of 0.083 to 1, details of which are described in the applicant's patent dated December 23, 1983. It is described in the application "Positive Photosensitive Resin Composition". The 1,2-quinonediazide compound represented by the above general formula () is, for example, ethylene glycol-
di(2-hydroxybenzoate), diethylene glycol-di(2,3-dihydroxybenzoate), triethylene glycol-di(2,6-
dihydroxybenzoate), ethylene glycol di(3,4,5-trihydroxybenzoate), triethylene glycol di(2-hydroxy-3-methylenebenzoate), ethylene glycol di(4-chloro-2-hydroxybenzoate) , polyethylene glycol di(5-
Bromo-2-hydroxybenzoate), Propylene glycol-di(3-chloro-4-hydroxybenzoate), Styrene glycol-di(2
-hydroxy-3-methoxybenzoate), polypropylene glycol-di(2-hydroxy-
5-methoxybenzoate), poly-3,3-bischloromethyloxetane glycol-di(3-
hydroxy-4-methoxybenzoate), 1,
3-propanediol-di(3,4,5-trihydroxybenzoate), 1,4-butanediol-di(3-hydroxybenzoate), polytetrahydrofuran glycol-di(3,4,5-
polyhydroxy compounds such as trihydroxybenzoate) and 1,2-naphthoquinonediazide-5
-Fluphonyl chloride, 1,2-naphthoquinonediazide-4-sulfonyl chloride or 1,2-
It can be obtained by condensing benzoquinone diazide-4-sulfonyl chloride at an equivalent ratio of 0.17 to 1. The 1,2-quinonediazide compound represented by the above general formula () is, for example, ethylene glycol-monomethyl-mono(3,4,5-trihydroxybenzoate), ethylene glycol-monoethyl-mono(2,4,6-trihydroxybenzoate), hydroxybenzoate), diethylene glycol monoethyl
Mono(2,3-dihydroxybenzoate), triethylene glycol-monoethyl-mono(3,
5-dihydroxybenzoate), ethylene glycol-monophenyl-mono(3,4,5-trihydroxybenzoate), 1,2-benzenedimethanol-monoethyl-mono(3,4,5-trihydroxybenzoate), etc. Hydroxy compound and 1,2-naphthoquinonediazide-5
-sulfonyl chloride, 1,2-naphthoquinonediazide-4-sulfonyl chloride or 1,2-
It can be obtained by condensing benzoquinone diazide-4-sulfonyl chloride at an equivalent ratio of 0.3 to 1. Details of the 1,2-quinonediazide compound represented by the above general formula () or () are described in the applicant's patent application "Positive photosensitive resin composition" dated January 10, 1980. The above 1,2-quinonediazide compounds may be used alone or in combination of two or more. Examples of the organic solvent used to dissolve the alkali-soluble resin and the 1,2-quinonediazide compound include glycols such as ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, and diethylene glycol dibutyl ether. Ethers, methyl cellosolve acetate,
Cellosolve esters such as ethyl cellosolve acetate and butyl cellosolve acetate, aromatic hydrocarbons such as toluene and xylene, ketones such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, acetonyl acetone, acetophenone, and isophorone, benzyl ethyl ether, Ethers such as 2-dibutoxyethane and dihexyl ether, fatty acids such as caproic acid and caprylic acid, 1-octanol, 1-
Alcohols such as nonanol, 1-decanol, benzyl alcohol, ethyl acetate, butyl acetate, 2-ethylhexyl acetate, benzyl acetate, benzyl benzoate, diethyl oxalate, dibutyl oxalate, diethyl malonate, dimethyl maleate, diethyl maleate , dibutyl maleate, dimethyl phthalate, ethylene carbonate, propylene carbonate, and other esters, and one type or a combination of two or more of these can be used. The amount of this organic solvent used varies depending on the required film thickness or coating method when applying the resist composition, but it is usually 100 to 2000 parts by weight per 100 parts by weight of the alkali-soluble resin used in the present invention. parts, preferably 300 to 1500 parts by weight. Furthermore, a surfactant can be added to the resist composition of the present invention in order to improve developability. Examples of surfactants include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, and polyoxyethylene oleyl ether; polyoxyethylene octyl phenol ether and polyoxyethylene nonyl phenol ether; Examples include polyethylene glycol dialkyl esters such as oxyethylene alkyl phenol ethers, polyethylene glycol dilaurate, and polyethylene glycol distearate. Furthermore, storage stabilizers, dyes, pigments, etc. can be added to the resist composition of the present invention, if necessary. In addition, in order to improve the adhesion between the coating film of the resist composition of the present invention and a substrate such as a silicon oxide film,
Hexamethyldisilazane, chloromethylsilane, or the like can also be applied to the substrate in advance. Examples of the developer for developing the resist coating film formed by the resist composition of the present invention include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate,
Inorganic alkalis such as aqueous ammonia, primary amines such as ethylamine and n-propylamine, secondary amines such as diethylamine and di-n-propylamine, tertiary amines such as triethylamine and methyldiethylamine, and dimethylethanolamine. , alcohol amines such as triethanolamine, quaternary ammonium salts such as tetramethylammonium hydroxide, tetraethylammonium hydroxy, pyrrole, piperidine,
1,8-diazabicyclo(5,4,0)-7-undecene, 1,5-diazabicyclo(4,3,
0) When fabricating integrated circuits where aqueous solutions of alkalis such as cyclic amines such as -5-nonane are used and the use of metal-containing developers becomes a problem, aqueous solutions of quaternary ammonium salts and cyclic amines are used. It is preferable to use Further, an aqueous solution obtained by adding an appropriate amount of a water-soluble organic solvent such as an alcohol such as methanol or ethanol, or a surfactant to the aqueous solution of the alkali mentioned above can also be used as the developer. As is clear from the Examples described later, the resist composition of the present invention is a positive resist composition having excellent heat resistance, dry etching resistance, and high resolution, and is used as a positive resist composition for producing integrated circuits. It is not only particularly useful as a mold resist, but also useful as a positive resist for mask production. EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples. Example 1 12 g of polyhydroxystyrene "Resin M" (manufactured by Maruzen Petrochemical Co., Ltd.) having a number average molecular weight of 10,000 was dissolved in 100 g of pyridine dried with potassium hydroxide, and the solution was chlorinated while keeping the temperature at 10 ° C. After adding acetyl dropwise for about 30 minutes, the temperature was further increased to 25°C.
Stirred at ℃ for 1 hour. The reaction product solution thus obtained was added to 1500 ml of vigorously stirred methanol, and the precipitate (polymer) produced was collected.
This precipitate was purified by dissolving it in 50 g of tetrahydrofuran, reprecipitating it with 800 ml of methanol, and then drying it under reduced pressure. The thus obtained polymer was analyzed by 1H-nuclear magnetic resonance spectroscopy (hereinafter referred to as "NMR analysis") and infrared absorption spectrum analysis (hereinafter referred to as "IR analysis"). It was found that it contains the repeating structural unit shown below.

【formula】

[Formula] Further, NMR analysis revealed that the proportion of p-acetoxystyrene units to the total repeating structural units was 19%. Next, 10 g of the above polymer and 2.3 g of 2,3,4-trihydroxybenzophenone-tri(1,2-naphthoquinonediazide sulfonyl ester)
was dissolved in 47 g of cellosolve acetate, and this solution was filtered using a membrane filter with a pore size of 0.2 μm to prepare a resist composition solution. After spin-coating this resist composition solution onto a silicon substrate having a thermal oxide film with a thickness of 7000 Å,
It was heated and dried for 25 minutes in a circulating oven kept at 0.degree. C. to obtain a resist coating film with a thickness of 1.2 .mu.m. This resist coating is applied to the mask aligner “PLA501F”.
(manufactured by Canon Inc.) at an exposure dose of 18 mJ/cm ² through a pattern mask with a line width of 0.6 μm, and development was performed using a 1.5% by weight aqueous solution of tetramethylammonium hydroxyoxide. However, a resist coating film was formed in which the pattern of the mask was faithfully transferred. When the residual film rate was measured, it was 97%. Here, the residual film rate is calculated by multiplying by 100 the value of the quotient (a/b) obtained by dividing the film thickness value of the pattern after development (a) by the film thickness value before development (b). %
It is expressed with the unit of . This substrate is then placed in a variable temperature air circulating oven.
After post-baking for 30 minutes, the heat resistance temperature was examined using a scanning electron microscope and found to be 160°C. The heat resistance temperature here is based on the temperature at which the corners of the resist coating film forming the pattern are rounded. Example 2 12 g of polyhydroxystyrene "Range M" with a number average molecular weight of 10,000 was dissolved in 100 g of pyridine dried using potassium hydroxide, and while maintaining this solution at a temperature of 15°C, 1,2-naphthoquinonediazide-5 was dissolved. - After adding 3 g of sulfonyl chloride little by little over 30 minutes, the mixture was further stirred at a temperature of 25°C for 1 hour. The resulting reaction product liquid was treated in the same manner as described in Example 1 to obtain a polymer. When this polymer was analyzed by NMR analysis and IR analysis, it was found that it contained the repeating structural units shown below.

【formula】

[Formula] Also, according to NMR analysis, the ratio of p-(1,2-naphthoquinonediazide-5-sulfonyloxy)-styrene units to the total repeating structural units is 11
%. Next, 10 g of the above polymer and 1.8 g of 2,3,4-trihydroxybenzophenone-tri(1,2-naphthoquinonediazide sulfonyl ester)
was dissolved in 47 g of cellosolve acetate, and this solution was filtered using a membrane filter with a pore size of 0.2 μm to prepare a resist composition solution. A resist coating film was formed using this resist composition solution in the same manner as described in Example 1, and further exposed and developed. As a result, a resist coating film with the pattern of the mask faithfully transferred was obtained. Been formed. When we measured the residual film rate, it was 98.
It was %. Next, the heat resistance temperature of the resist coating film was examined by the same method as described in Example 1, and it was found to be 165°C. Comparative example 1 In a three-necked separable flask with an internal volume of 500ml
- After charging 100 g of cresol, 66 ml of a 37% by weight formalin aqueous solution and 0.04 g of oxalic acid were added.
While stirring, the separable flask was immersed in an oil bath to control the reaction temperature at 100°C, and the reaction was carried out for 10 hours to synthesize a novolak resin.
After the reaction, the pressure was reduced to 30 mmHg to remove water, and the internal temperature was further raised to 130°C to remove unreacted substances. Then, the molten alkali-soluble novolak resin was returned to room temperature and recovered. Next, 10 g of this resin and 2.3 g of 2,3,4-trihydroxybenzophenone-tri(1,2-naphthoquinonediazide sulfonyl ester) were dissolved in 47 g of cellosolve acetate, and this solution was poured into a membrane with a pore size of 0.2 μm. It was filtered using a filter to prepare a resist composition solution. A resist coating film was formed using this resist composition solution in the same manner as described in Example 1, and exposure and development were carried out in the same manner as in Example 1 except that the exposure amount was 16 mJ/cm ² . As a result, a resist coating film was formed to which the pattern of the mask was transferred. When we measured the residual film rate, we found that it was 82.
It was %. Next, the heat resistance temperature of the resist coating film was examined by the same method as described in Example 1, and it was found to be 130°C. Comparative Example 2 10 g of polyhydroxystyrene “Range M” with a number average molecular weight of 10,000 and 1.8 g of 2,3,4-trihydroxybenzophenone-tri(1,2-naphthoquinonediazide sulfonyl ester) were dissolved in 47 g of cellosolve acetate. and add this solution to the pore size
Filter using a 0.2 μm membrane filter,
A resist composition solution was prepared. A resist coating film was formed using this resist composition solution in the same manner as described in Example 1, and exposure and development were carried out in the same manner as in Example 1 except that the exposure amount was 17 mJ/cm ² . As a result, a resist coating film was formed to which the pattern of the mask was transferred. When we measured the residual film rate, we found that it was 72.
It was %. Next, the heat resistance temperature of the resist coating film was examined by the same method as described in Example 1, and it was found to be 150°C. Comparative Example 3 10 g of the polymer obtained in Example 2 was dissolved in 47 g of cellosolve acetate, and this solution was filtered using a membrane filter with a pore size of 0.2 μm to prepare a resist composition solution. A resist coating film was formed using this resist composition solution in the same manner as described in Example 1, and was further exposed and developed. It was not possible to obtain a pattern because the difference in solubility was small. Examples The dry etching resistance of the resist patterns obtained in Examples 1 and 2 and Comparative Examples 1 and 2 was evaluated using a parallel plate dry etching apparatus (electrode spacing of 40 mm) using carbon tetrachloride as an etching gas. The test was conducted under the conditions of an output of 100 W and a gas pressure of 15 Pa. Table 1 shows the relative etching rates when the etching rate of PMMA (polymethyl methacrylate) is set to 1. This indicates that the resist coating film formed using the resist composition of the present invention has good dry etching resistance.

【table】

Claims (1)

[Scope of Claims] 1 The proportion of repeating structural units represented by the following general formula (A) is 20 to 95%, and the repeating structural units represented by the following general formula (B) and/or the following general formula (C) are 20 to 95%. 1. A positive resist composition comprising an alkali-soluble resin having a repeating structural unit ratio of 5 to 80%, and a 1,2-quinonediazide compound. General formula (A) General formula (B) General formula (C) (In the formula, R ¹ to ^{R 4} are hydrogen atoms, R ⁵ is an alkyl group having 1 to 4 carbon atoms, or 1,
2-quinonediazide group, R ⁶ is a hydrogen atom or a methyl group. )