JPH0237348A - Positive type photosensitive resin composition - Google Patents

Abstract

PURPOSE:To improve the resolution, the heat resisting property and the process stability of the title composition by incorporating an alkali soluble novolak resin obtd. by polycondensating various kinds of phenols with an aldehyde, in a specified compd. CONSTITUTION:The composition is composed of the alkali soluble novolak resin obtd. by polycondensating the compd. shown by formula I and the phenols. In the formula, X1 and X2 are each hydrogen atom or hydroxymethyl group, R1 and R2 are each 1-4 C alkyl group, Y is C=O or C(R3)(R4) group, R3 and R4 are each hydrogen atom or methyl group, etc., (m) and (n) are each 0 or an integer of 1 or 2. A 1,2-quinone diazide compd. is incorporated in the alkali soluble novolak resin in an amount of 20-50pts.wt. of the compd. per 100pts.wt. of the resin. The sensitivity, the resolution, the heat resisting property and the process stability of the composition are improved.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention provides an alkali-soluble novolac resin and a 1°2- The present invention relates to a positive photosensitive resin composition comprising a quinonediazide compound.

[Prior Art] In recent years, the density and integration of semiconductor integrated circuits have progressed, and as we enter the era of 4 Mbits or more of integration, pattern formation of submicron rules and even smaller ones has become necessary.

The positive photoresist consists of an alkali-soluble novolak resin and a 1°2-quinonediazide compound that functions as an alkali dissolution inhibitor.

In the radiation irradiated part, the 1,2-quinonediazide compound becomes ketene via carbene, reacts with moisture inside and outside the system to produce indene carboxylic acid, and becomes easily dissolved in the alkaline aqueous solution. On the other hand, the unirradiated area is dissolved in an alkaline developer, hardly swells, and maintains a high residual film ratio. As a result, a high resolution resist pattern is obtained. Conventional Rika polyisoprene-based negative photoresists have limited resolution due to swelling of the film during development, and recently positive photoresists have been mainly used. By the way, in order to meet increasingly strict demands,
Various improvements have been attempted in positive photoresists, including resins, photosensitizers, developers, and additives.
A wide-ranging and detailed study is being conducted. In particular, high sensitivity, high resolution, rectangularity of pattern profile, high dry etching resistance, high heat resistance, and process stability are strongly desired and are the goals of improvement.

[Problem to be solved by the invention] However, sensitivity and resolution, sensitivity and heat resistance, and sensitivity,
Resolution, heat resistance and process stability tend to contradict each other. For example, increasing the molecular weight of the resin increases heat resistance, but reduces sensitivity, resolution, pattern profile rectangularity, and process stability. If copolymerization is performed to improve heat resistance, the rectangularity of the pattern profile and process stability will decrease. Furthermore, when the amount of photosensitizer is increased, the resolution improves, but the sensitivity decreases. As described above, since there are many contradictory properties, it has been extremely difficult to achieve high performance without degrading other properties.

[Means for Solving the Problems] As a result of intensive research based on the above background, the present inventors solved the above-mentioned problems by regulating the structure of the polymer to some extent when synthesizing an alkali-soluble resin. We have found that this can be solved and have arrived at the present invention.

In other words, by using the alkali-soluble novolac resin obtained by polycondensing various phenols with aldehyde using the compound (1) of the present invention as a starting material, resolution and patterning can be improved while maintaining sensitivity and process stability. They have discovered that the profile and heat resistance can be improved, and have completed the present invention.

That is, the present invention provides a positive photosensitive resin composition comprising an alkali-soluble novolak resin synthesized by polycondensation from phenols, aldehydes, and acid catalysts and a 1,2-quinonediazide compound, in which the alkali-soluble resin has the general formula (
1) (However, Xl and X2 each represent a hydrogen atom or a hydroxymethyl group, and may be the same or different from each other: R1 and R2 each represent a C1 to 4 alkyl group, and both are the same may also be different from each other: Y is 2Cw Ql-8-2SO2 or 2C(R3
) (R4), in which R5 and R4 each represent a hydrogen atom, a methyl group, an ethyl group, or a phenyl group, and may be the same or different from each other: m, Alkali-soluble novolak resin obtained by polycondensation of a compound represented by (n represents either 0.1 or 2 and may be the same or different from each other) and a phenol. The present invention provides a positive photosensitive resin composition resin composition characterized by the following.

In addition, various phenols used in the polycondensation with the compound (1) of the present invention include, for example, phenol, O-cresol, m-cresol, p-cresol, 0-ethylphenol, m-ethylphenol, p- Ethylphenol, 0-n-butylphenol, m-n-butylphenol, p-n-butylphenol, 0-t-butylphenol, m-t-butylphenol, p-t-butylphenol, O-methoxyphenol, m-methoxyphenol, p -methoxyphenol, O-fluorophenol, m-fluorophenol, p-fluorophenol, O-chlorophenol, m-chlorophenol,
Examples include p-chlorophenol, 0-nitrophenol, m-nitrophenol, p-nitrophenol, 2.4-xylenol, 2.5-xylenol, 3.4-xylenol, 3.5-xylenol, and the like. Furthermore, the hydroxyl group of phenol may be substituted with sulfonic acid or carboxylic acid ester, if necessary. Esterification components include alkyl groups such as methyl, ethyl, propyl, phenyl, tolyl, benzoic acid, naphthyl, benzyl,
Examples include aromatic rings such as cumyl and phenethyl.

The method for synthesizing compound (1) of the present invention is not particularly limited, but it can be synthesized, for example, by the following method.

One mole of commercially available bisphenol A, bisphenol B, bisphenol S, etc. is dissolved in an aqueous solution of caustic soda, and after cooling, formalin or paraformaldehyde is added and reacted. Thereafter, the precipitate is filtered, dissolved in a small amount of water, and neutralized to obtain the desired compound.

Alternatively, the target compound can be obtained by performing similar experiments using phenol, cresol, or the various phenols described above instead of bisphenol A, bisphenol B, bisphenol S, or the like.

Next, an example of a method for synthesizing an alkali++J-soluble novolak resin using the compound (1) of the present invention will be shown.

The compound of the present invention is dissolved in a high boiling point solvent, and then the above-mentioned various phenols and catalysts are added in required amounts and rapidly heated. Then, aldehyde is added dropwise to produce a resin. Alternatively, the above-mentioned phenols may be melted above their melting point, the compound and catalyst of the present invention may be added thereto, and then the aldehyde may be added. The aldehyde used here is not particularly limited, but examples include feraldehyde,
Examples include paraformaldehyde, acetaldehyde, and phenylaldehyde. Similarly, the catalyst is not particularly limited, but examples thereof include formic acid, oxalic acid, acetic acid, hydrochloric acid, sulfuric acid, nitric acid, and Lewis acid. Further, some of the hydroxyl groups in the resin of the present invention may be esterified with a sulfonyl group or a carbonyl group. Esterification is obtained by reacting the resin of the present invention with a sulfonyl halide or a carbonyl halide in the presence of a base such as potassium hydroxide, sodium hydroxide, alkali carbonate, triethylamine, or pyridine.

The weight average molecular weight of the novolak resin using the compound of the present invention is preferably 1,500 to 30,000 (in terms of polystyrene). Further, the copolycondensation ratio of the compound of the present invention and the above-mentioned phenols is not particularly limited and may be anywhere from 0.01 to 99.99 mol%, but preferably the content of the compound of (1) of the present invention is is preferably 1 to 20 mol%. Within the above range, sensitivity, resolution, heat resistance, and process stability are excellent.

The 1,2-quinonediazide compound used in the present invention is, for example, 1,2-naphthoquinone di,azido-4-
Sulfonic acid ester, 1,2-naphthoquinonediazide-
It is a 5-sulfonic acid ester, and the ester components include polyhydroxybenzophenones such as trihydroxybenzophenone, tetrahydroxybenzophenone, and hexahydroxybenzophenone, alkyl gallates such as methyl gallate, flavones such as quercetin, trihydroxybenzene, trihydroxy Examples include polyhydroxyphenylalkyl ketones such as phenyl-n-hexyl ketone, dihydroxydiphenylmethane, dihydroxydiphenylpropane, dihydroxydiphenylhexafluoropropane, dihydroxydiphenylsulfone, and dihydroxydiphenylamine. The 1,2-quinonediazide compound is an alkali-soluble novolac resin 1
00 parts by weight, preferably 20 to 50 parts by weight. Within this range, a sufficient difference in solubility in the developer between exposed and unexposed areas can be obtained, and a pattern with excellent sensitivity and resolution can be obtained.

The positive photosensitive resin composition of the present invention is obtained by dissolving the alkali-soluble novolak resin and the 1,2-quinonediazide compound in a suitable solvent so that the solid content becomes 20 to 40 parts by weight. Examples of the solvent include ethylene glycol monoalkyl ether and its acetates, propylene glycol monoalkyl ether and its acetates, diethylene glycol dialkyl ethers, ketones such as methyl ethyl ketone and cyclohexanone, acetic acid esters such as ethyl acetate and butyl acetate, Examples include aromatic hydrocarbons such as toluene and xylene, dimethylacetamide, and dimethylformamide. These solvents can be used alone or in combination of two or more. Furthermore, if necessary, a nonionic, fluorine-based, silicone-based surfactant, etc. can be added to improve the coating properties. Furthermore, compatible additives such as sensitizers, color toners, stabilizers, etc. can be blended.

[Function] The positive photosensitive resin composition comprising an alkali-soluble novolak resin and a 1°2-quinonediazide compound of the present invention can be used for resist pattern formation using ultraviolet rays, deep ultraviolet rays, electron beams, X-rays, etc. , sensitivity, resolution,
Excellent heat resistance and process stability.

There are no particular limitations on the method of use when forming a resist pattern by radiation using the positive photosensitive resin composition comprising the alkali-soluble novolak resin and 1゜2-quinonediazide compound of the present invention, and the method is carried out according to a conventional method. be able to.

For example, the positive photosensitive resin composition of the present invention is prepared by dissolving an alkali-soluble novolac resin, a 1,2-quinonediazide compound, and additives in a solvent, and filtering the solution through a 0.2 μm filter. A resist film is obtained by spin-coding the resist solution onto a substrate such as a silicon wafer and subjecting it to brebake. after that,
Exposure is performed using a reduction projection exposure device, an electron beam exposure device, etc.
A resist pattern can be formed by developing.

As a developer, for example, an aqueous organic alkali solution such as a quaternary ammonium salt such as tetramethylammonium hydroxide or choline, an amine, or an aqueous inorganic alkali solution such as sodium hydroxide, potassium hydroxide, sodium carbonate, or aqueous ammonia. can be used. Other methods such as coating, blebake, exposure, development, etc. can be carried out by conventional methods.

[Examples] Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto.

Synthesis Example 1 Bisphenol A was placed in a 1.0OOrd 4 flask.
After cooling, 200 g of 37% formalin aqueous solution was added to a 30% aqueous solution of 228 g of sodium hydroxide and 40 g of caustic soda, and the mixture was left to stand at room temperature for about a week to obtain a crystalline precipitate. This was filtered out and alcohol After drying, it was dissolved in a small amount of water and neutralized with acetic acid.The precipitate was filtered and dried to obtain 174g of colorless needle-shaped crystals.When reverse layer chromatography was performed, there was only one peak. The elemental analysis values were C65.2%, H7.1%.3.5.3-5-Tetramethylol-4,4''-
Theoretical value of dihydroxydiphenylpropane C65.5%
, H6.9%.

Synthesis Example 2 Bisphenol A2 was added to a 1000mj 4-tube flask.
28g r, caustic soda 40g as a 30% aqueous solution,
After cooling, 37% formalin aqueous solution 1 ('J Og r
After addition, a crystalline precipitate was obtained upon standing at room temperature for about a week. This was filtered off, washed with alcohol, dried, dissolved in a small amount of water, and neutralized with acetic acid. The precipitate was filtered and dried to obtain 114 gr of colorless needle crystals. The elemental analysis values were C69,496 and H6.8%. The average methylolization rate was 2.58 based on elemental analysis.

Synthesis Example: Add 40 gr of caustic soda to 94 gr of carbolic acid in a 1,000 d 4-tube flask to make a 30% aqueous solution, and after cooling, the solution was 37%
243 gr of formalin was added and left at room temperature for 51 hours. The precipitate was filtered, washed with alcohol, dried, and then dissolved in a small amount of water. Next, after neutralizing with dilute acetic acid, the washed product was filtered.
After drying, 129g of colorless needle-like crystals were obtained.

When this compound was subjected to i11 determination by reverse layer chromatography, there was only one peak. The elemental analysis value is C63,
106, H6.5%, which was in very good agreement with the theoretical value.

(3,5,3゛ 5″-tetramethylol-4,4′-
Theoretical value of dihydroxydiphenylmethane 063.8%,
H6, 3%) Synthesis Example 4 Metacresol 11 in a 300rIdl 4 flask
5 gr, 37% formalin 13.3 gr.

Mix 0.2g of concentrated hydrochloric acid, gradually add hot water, and boil under reflux for 2 hours.
Allowed time to react. Next, after heating and concentrating to 160° C. to remove water, unreacted cresol was recovered under reduced pressure. Furthermore, fractions from 180°C to 230°C were collected under reduced pressure of 0.5 mmHg. When measured by reverse layer chromatography, there were three peaks. After column separation, elemental analysis of each compound and all J determination based on "C,'HNMRi," revealed that 4.4'-dihydroxy-2,2'-dimethyldiphenylmethane and 2,4'-dihydroxy-
4,2′-dimethyldiphenylmethane and 2,2′-
It was found to be a mixture of dihydroxy-4,4'-dimethyldiphenylmethane. Using this mixture, a tetramethylol compound was synthesized in the same manner as in Synthesis Example 1.

Synthesis example 5 Bisphenol S instead of bisphenol A228gr
A tetramethylol compound was synthesized in exactly the same manner as in Synthesis Example 1 except that 250 gr of was used.

Reverse layer chromatography revealed only one peak. Elemental analysis values are 051.1%, H4.9%,
It was 88.9%. 3.5.35'-Tetramethylol-4,4''-dihydroquine diphenylsulfone, which was almost in agreement with the theoretical values of C51,996, H4, 9%, and 88.7%.

Synthesis Example 6 12g of the compound obtained in Synthesis Example 1 and 50g of m-cresol were placed in a 500d 4 flask.

p-cresol 30 grs o-cresol 20
gr, and 1.75 gr of oxalic acid dihydrate were added thereto, and the mixture was immersed in an oil bath under a nitrogen atmosphere without stirring, and the temperature was raised until the internal temperature reached 120°C. After 30 minutes of reaction, the molecular weight was 650.
The reaction was continued under reflux while adding 3706 formalin dropwise until the temperature reached 0 (polystyrene equivalent). After the reaction was completed, 108 gr of resin powder was obtained by repeating dissolution and precipitation, followed by drying. Accurate ff1ff of novolac resin
The i-average molecular weight was 6750 in terms of polystyrene as a result of G P CAFI determination. Further, the degree of dispersion was 3.98.

Synthesis Example 7 A resin was synthesized in exactly the same manner as in Synthesis Example 6 except that 12 g of the compound of Synthesis Example 2 was used instead of 12 g of the compound of Synthesis Example 1. The weight average molecular weight of the resin was 6470. Dispersion The degree was 4.0.

Synthesis Example 8 8.5g of the compound of Synthesis Example 3, 60g of m-cresol
", p-cresol 40g, oxalic acid dihydrate 1.75g
Add r and use the same method as Synthesis Example 6 to prepare 1-1 standard molecule M:L7.
500 resins were synthesized. As a result of G P Cr11 constant, the weight average molecular weight was 7,450. The degree of dispersion was 4.25.

Synthesis Example 9 9.7g of the compound of Synthesis Example 4, 60g of m-cresol
r, p-cresol 40 gr, oxalic acid dihydrate 1.75
target molecule E1730 in the same manner as Synthesis Example 6 by adding gr.
0 resin was synthesized. As a result of GPC measurement, the weight average molecular weight was 7,300. The degree of dispersion was 4.20.

Synthesis Example 10 A resin was synthesized in exactly the same manner as in Synthesis Example 6 except that 13 g of the compound of Synthesis Example 5 was used instead of 12 g of the compound of Synthesis Example 1. As a result of GPC δ-1 constant, the weight average molecular weight was 6.
It was 980. The degree of dispersion was 3.95.

Synthesis Example 11 120d of diethylene glycol dimethyl ether was charged into a 500rR1 4-tube flask, and then 92gr of bisphenol S12.5g and 37% formalin were added.
, 4.15 gr of oxalic acid dihydrate are added. Temperature 80℃
After 90 minutes, 60g of m-cresol, which had been previously heated to 80°C.

A mixture of 40 g of p-cresol was added at once. After the addition, the oil bath was raised until the internal temperature reached 125°C, and the reaction was continued for about 5 hours while maintaining this temperature. After that, vacuum distillation was performed to remove unreacted Monomer and solvent were distilled off.

This polymer had a ff1W average molecular weight of 6250 and a dispersity of 4.03.

Synthesis Example 12 2.3.4-Trihydroxybenzophenone 5. Ogr and 1,2-naphthoquinonediazide-5-sulfonyl chloride 15.8
gr in dioxane 100 gr, and while stirring at room temperature triethylamine 7, Ogr dioxane solution 2
0mj! was added dropwise over 30 minutes. Thereafter, the reaction was continued for 3 hours. After the reaction, the triethylamine hydrochloride was filtered, and the filtrate was poured into a large amount of ion-exchanged water.2.3.4
- A 1.2 quinonediazide compound of trihydroxybenzophenone was precipitated. Filter this, ion exchange water,
After sequentially washing with ethanol, drying and powder 17.
I got 9gr. Elemental snoring result C55.3%, H2.9
%, N9.1, and S10.2.

Example 1 8 gr of the resin obtained in Synthesis Example 6 and 2.21 gr of 1,2-quinonediazide obtained in Synthesis Example 12 were dissolved in 24 g of ethylene glycol monoethyl ether acetate and filtered through a 0.2 μm microfilter. It was filtered to obtain a resist solution. This resist solution was applied onto a 4-inch wafer using a spinner, and prebaked at 90°C for 30 minutes in a circulating constant temperature bath to obtain a resist film with a thickness of 1.5 μm. Next, a reduction projection exposure device (manufactured by GCA, DSW
-6300A%N,A, -0,35) was used to expose through the reticle. Immersion development was performed at 25° C. for 1 minute using a 2.38 fII mass % aqueous solution of tetramethylammonium hydroxide as a developer.

The exposure dose for developing 1.0 μm lines/spaces in a 1:1 ratio was 165 mJ/am 2 , and with the same exposure amount, it was possible to develop 0.65 μm lines/spaces in a 1:1 ratio, and the mask fidelity was also good. The resolution could be resolved down to 0.65 μm under the same exposure amount, and the pattern was rectangular. 0.60μm
could also be resolved, but the shape was slightly trapezoidal.

Next, one 3 μm line/space pattern was created.
40.145.150.155.160゜165.17
The heat resistance was evaluated by baking at each temperature of 0° C. for 30 minutes in a circulating constant temperature bath. As a result, no pattern deformation was observed up to 150°C.

Example 2 8 gr of the resin obtained in Synthesis Example 7 and 2.25 gr of 1,2-quinonediazide obtained in Synthesis Example 12 were dissolved in 24 g of ethylene glycol monoethyl ether acetate and filtered through a 0.2 μm microfilter. It was filtered to obtain a resist solution. This resist solution was applied onto a 4-inch wafer using a spinner, and prebaked at 90°C for 30 minutes in a circulating constant temperature bath to obtain a resist film with a thickness of 1.5 μm. .Next, a reduction projection exposure device CGCAGCA W
-6300A,N,A, -0,35) was used to expose through the reticle. Immersion development was performed at 25° C. for 1 minute using a 2.38% by weight aqueous solution of tetramethylammonium hydroxide as a developer.

The exposure amount to develop 1.0 μm line/space one to one is 170 mJ/cm2, and 0 at the same exposure amount.
．． One-to-one development was possible up to 70 μm line/space, and the mask fidelity was also good. Resolution is 0 under the same - exposure amount
．． It was possible to resolve up to 70 μm, and the pattern was rectangular.

0.65 μm could also be resolved, but the shape was trapezoidal.

Next, one 3 μm line/space pattern was created.
40.145.150.155.160.165.17
The heat resistance was evaluated by baking at each temperature of 0° C. for 30 minutes in a circulating constant temperature bath. As a result, no pattern deformation was observed up to 150°C.

Example 3 7.5g of the resin obtained in Synthesis Example 8 and 2.25g of 1,2-quinonediazide obtained in Synthesis Example 12 were dissolved in 24g of ethylene glycol monoethyl ether acetate, and filtered through a 0.2 μm microfilter. Perform filtration at
This was used as a resist solution. This resist solution was applied onto a 4-inch wafer using a spinner, and prebaked at 90° C. for 30 minutes in a circulating constant temperature bath to obtain a resist film with a thickness of 1.5 μm. Next, exposure was performed through the reticle using a 5:1 reduction projection exposure machine (g-line) with N and A of 0.45. Immersion development was performed at 25° C. for 1 minute using a 2.38% by weight aqueous solution of tetramethylammonium hydroxide as a developer.

The exposure amount for developing 1.0 μm lines/spaces in a 1:1 ratio was 158 mJ/cm 2 , and with the same exposure amount, it was possible to develop 0.55 μm lines/spaces in a 1:1 ratio, and the mask fidelity was also good. The resolution could be resolved down to 0.55 μm under the same exposure amount, and the pattern was rectangular. 0.50μm
could also be resolved, but the shape was slightly trapezoidal.

Next, one 3 μm line/space pattern was created.
40.145.150.155.1601165.17
The heat resistance was evaluated by baking at each temperature of 0° C. for 30 minutes in a circulating constant temperature bath. As a result, no pattern deformation was observed up to 145°C.

Example 4 A photosensitizer obtained by esterifying commercially available 1.3.5-)rihydroxybenzene (Tokyo Kaseihin) with an average of 2.5 moles of 1.2-naphthoquinonediazide-4-sulfonyl chloride was prepared in the same manner as in Synthesis Example 12. Synthesized with.

7.5 gr of synthetically obtained resin and 2.0 gr of the photosensitizer
gr was dissolved in 24 gr of ethylene glycol monoethyl ether acetate and filtered through a 0.21 trn microfilter to obtain a resist solution. This resist solution was coated on a 4-inch wafer using a spinner, and kept in a constant cycle at 90°C for 30 minutes. Prebaking was performed in an M tank to obtain a resist film with a thickness of 1.5 μm. Next, N, A,
Using a 5:1 reduction projection exposure machine (i-line) with a ratio of 0.42,
Exposure was made through the reticle. Using a 2.38% by weight aqueous solution of tetramethylammonium hydroxide as a developer, 7-point development was performed at 25° C. for 1 minute.

The exposure dose for developing 1.0 μm lines/spaces in a 1:1 ratio was 178 mJ/cm 2 , and with the same exposure amount, it was possible to develop 0.50 μm lines/spaces in a 1:1 ratio, and the mask fidelity was also good. The resolution could be resolved down to 0.50 μm under the same exposure amount, and the pattern was rectangular.

Example 5 8 gr of the resin obtained in Synthesis Example 10 and commercially available 2.3.4.
1.2 per mole of 4'-tetrahydroxybenzophenone
- 2.0 gr of a photosensitizer (purchased from Toyo Gosei) made by esterifying naphthoquinone diazide-5-sulfonyl chloride with an average of 3.2 moles was dissolved in 24 gr of ethylene glycol monoethyl ether acetate, and filtered through a 0.2 μm microfilter. A resist solution was obtained. Using this resist solution, spin a 4-inch wafer using a spinner.
A resist film having a thickness of 1.5 μm was formed by coating the resist film on top and pre-baking it at 90° C. for 30 minutes in a circulating constant temperature bath. Next, a 5:1 reduction projection exposure machine (g-line) with N and A of 0.45.
was used to expose light through the reticle. As a developer,
Tetramethylammonium hydroxide 2. 38f
Immersion development was performed at 25° C. for 1 minute using a flffi% aqueous solution.

The exposure amount for developing 1.0 μm lines/spaces on a 1:1 basis is 158 mJ/cm', and with the same exposure amount, it is possible to develop 0.60 am lines/spaces on a 1:1 basis.
Mask fidelity was also good. The resolution could be resolved down to 0.60 μm under the same exposure amount, and the pattern was rectangular.

Example 6 8 gr of resin of Synthesis Example 11 and 2.25 gr of photosensitizer of Synthesis Example 12
gr was dissolved in 24 gr of ethylene glycol monoethyl ether acetate and filtered through a 0.2 μm microfilter to obtain a resist solution. Using this resist solution, apply it onto a 4-inch wafer using a spinner,
1. Pre-bake in a circulating constant temperature bath at 90°C for 30 minutes.
A resist film with a thickness of 5 μm was obtained.

Next, a reduction projection exposure device manufactured by CGCA, DSW-6300
A, N, A, -0,35) was used to expose through the reticle. Using a 2.38ffiQ% aqueous solution of tetramethylammonium hydroxide as a developer,
Immersion development was performed at ℃ for 1 minute.

The exposure dose for developing 1.0 μm lines/spaces in a 1:1 ratio was 148 mJ/cm 2 , and with the same exposure amount, it was possible to develop 0.70 μm lines/spaces in a 1:1 ratio, and the mask fidelity was also good. The resolution could be resolved down to 0.65 μm under the same exposure amount, and the pattern was rectangular.

[Effects of the Invention] A positive photosensitive resin composition comprising an alkali-soluble novolac resin of the present invention and a 1°2-quinonediazide compound can be produced by controlling the structure of the novolak resin to a certain extent, that is, by using the compound of the present invention as a starting material. By using resins that have been dehydrated with various phenols,
Since it is possible to improve resolution, heat resistance, and pattern shape without impairing sensitivity and process stability, it is suitable for manufacturing semiconductor integrated circuit elements such as VLSI.

Claims (4)

[Claims] (1) Alkali-soluble novolak resin synthesized by polycondensation from phenols, aldehydes, and acid catalysts and 1,2
- In a positive photosensitive resin composition consisting of a quinonediazide compound, the alkali-soluble resin has the general formula (1) ▲ Numerical formula, chemical formula, table, etc. ▼ (1) (However, X_1 and X_2 are each a hydrogen atom or hydroxymethyl R_1 and R_2 each represent a C1 to 4 alkyl group, and may be the same or different: Y is ■C=O, -S-, ■SO_2 or ■C(
R_3) (R_4), which R_
3 and R_4 each represent a hydrogen atom, a methyl group, an ethyl group, or a phenyl group, and may be the same or different; m and n each represent a number of 0, 1, or 2; A positive photosensitive resin composition characterized in that it is an alkali-soluble novolak resin obtained by polycondensation of a compound represented by the formula (which may be the same or different from each other) and a phenol. . (2) The positive photosensitive resin composition according to claim 1, wherein X_1 and/or X_2 are hydroxymethyl groups. (3) The positive photosensitive resin composition according to claim 1 or 2, comprising an alkali-soluble novolak resin containing 0.01 to 99.99 mol% of the component represented by general formula (1). (4) The positive photosensitive resin composition according to any one of claims 1 to 3, comprising an alkali-soluble novolak resin containing 1 to 20 mol% of the component of general formula (1).