JPH0354565A - Pattern forming method - Google Patents

Abstract

PURPOSE:To improve sensitivity to exposure with UV having a prescribed wavelength, resolution and developability by forming a resist layer made of a compsn. contg. a specified alkali-soluble resin. CONSTITUTION:A resist layer is formed on a substrate by applying and drying a compsn. contg. an alkali-soluble resin obtd. by condensing prescribed phenols with aldehydes and a 1,2-quinonediazido compd. The resist layer is imagewise exposed with light having 300-380 nm wavelength and developed to form a pattern. The phenols are 20-80 mol% m-cresol, 0-50 mol% p-cresol and 20-80 mol% compd. represented by formula I other than m-cresolnd p-cresol. In formu la I, each of R<1>-R<3> is H, hydroxyl, 1-4C alkyl, etc.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a pattern forming method, in particular, a resist layer is formed using a specific photosensitive resin composition, and the resist layer is further exposed to light of a specific wavelength. The present invention relates to a resist pattern forming method characterized by including a step of exposing to light.

[Prior Art] In recent years, with the increase in the density of integrated circuits, a resolution of 1 μm or less than 1 μm is required in the formation of a resist pattern using a positive resist in the manufacture of integrated circuits.

One way to improve the resolution of this resist pattern is to expose the resist to light with a shorter wavelength than the conventionally used ultraviolet light. This method uses light with a wavelength shorter than 436 nm (hereinafter referred to as "G-line"), which is the exposure wavelength for resists currently commonly used, for example, 30 nm.
This is a method of exposing to ultraviolet light of 0 to 380 nm.

[Problem to be solved by the invention] However, the conventionally used positive resist has a
~380r+m UV absorption coefficient is large, so 30
When exposed to ultraviolet light with a wavelength of 0 to 380 nm, the ultraviolet light does not easily reach the bottom of the resist layer, resulting in problems such as a decrease in the sensitivity of the resist and poor pattern shape and developability.

As a solution to such problems, JP-A-63-1
No. 84745 discloses a positive resist composition suitable for exposure to ultraviolet light of 300 to 380 nm aimed at solving the above problems, but the positive resist composition disclosed in this patent However, there was a problem that the developability and heat resistance were insufficient.

The present invention solves the above problems and provides a method for forming a resist pattern that is excellent in sensitivity, resolution, residual film rate, and developability when forming a resist pattern, and also has excellent pattern shape and heat resistance of the resulting resist pattern. The purpose is to

[Means for Solving the Problems] The present invention provides the following features: (1) m-cresol 20 to 80 m-cresol on a substrate;
mol%, p-cresol 0 to 50 mol%, the following general formula (
At least one compound other than m-cresol and p-cresol selected from the compounds represented by I) 20
An alkali-soluble resin obtained by condensing a phenol consisting of ~80 mol% with an aldehyde (hereinafter referred to as "specific alkali-soluble resin"), and (2) 1.
A photosensitive resin composition containing a 2-quinonediazide compound (hereinafter referred to as "photosensitive resin composition") is applied and dried to form a resist layer, and the resist layer is
The present invention provides a pattern forming method characterized by including a step of exposing to light with a wavelength of 80 nm.

General formula (I) Rl [In the formula, R1 to R3 may be the same or different, and are a hydrogen atom, a hydroxyl group, a group represented by R4, OR4, or COOR4 (R4 is a methyl group, an ethyl group, a proyl group, a butyl (represents an alkyl group having 1 to 4 carbon atoms such as a group). ] In the present invention, among the phenols used in the synthesis of the specific alkali-soluble resin contained in the photosensitive resin composition used, compounds other than m-cresol and p-cresol represented by the above general formula (I) is, for example, 3,5-dimethylphenol, 2,5-dimethylphenol, 2,3-dimethylphenol, 2,4-dimethylphenol, 2,6-dimethylphenol, 3,4-dimethylphenol.
Dimethylphenol, 2,3.5-}limethylphenol, 3,4.5-1limethylphenol, 4-t-butylphenol, 2-t-butylphenol, 3-t-butylphenol, 2-methylres. Runnol, 4-methylresorcinol, 5-methylresorcinol, 4-t
-butylcatechol, 4-methoxyphenol, 3-methoxyphenol, 2-methoxyphenol, 2-methoxyphenol, 2-methoxyresorcinol, 3-methoxyresorcinol, 2,3-dimethoxyphenol, 2,5-dimethoxyphenol, 3 , 5-dimethoxyphenol, methyl gallate, ethyl gallate, methyl 3-methoxy-4,5-dihydroxybenzoate, ethyl 3-methoxy-4,5-dihydroxybenzoate, 4-methoxy-3,5-dihydroxybenzoic acid Methyl, ethyl 4-methoxy-3,5-dihydroxybenzoate, 3,4
-Methyl dimethoxy-5-hydroxybenzoate, 3,4
-Ethyl dimethoxy-5-hydroxybenzoate, 3,5
-Methyl dimethoxy-4-hydroxybenzoate, 3,5
-Ethyl dimethoxy-4-hydroxybenzoate, 3-ethylphenol, 2-ethylphenol, 4-ethylphenol, 3,4.5-trimethylphenol, 2,
3. 5-1 ethylphenol, 3,5-diethylphenol, 2,5-diethylphenol, 2,3-
diethylphenol, 3.4-diethylphenol, 2
-isoprobylphenol, 3-isobrobylphenol, 4-isopropylphenol, 2-propylphenol, 3-propylphenol, 4-propylphenol, 2-methoxy-5-methylphenol, 2-t-butyl-5- Examples include methylphenol, thymol, isothymol, and the like.

Among these, 2,5-dimethylphenol, 3,5-
Dimethylphenol, 2,3-dimethylphenol, 3
, 4-dimethylphenol, 2,3.5-}trimethylphenol and 3,4.5-trimethylphenol are preferably used.

These compounds may be used alone or in combination of two or more.

In the present invention, the phenols used in the synthesis of the specific alkali-soluble resin include m-cresol 20 to 80 mol%, preferably 30 to 70 mol%, and p-cresol 0 to 80 mol%.
50 mol%, preferably 0 to 40 mol%, general formula (I)
It consists of 20 to 80 mol%, preferably 30 to 70 mol% of compounds other than m-cresol and p-cresol represented by. Among these phenols, if the proportion of m-cresol used is less than 20 mol%, the sensitivity and developability of the photosensitive resin composition will deteriorate, and if it exceeds 80 mol%, the resolution, pattern shape, and heat resistance will deteriorate. Also, p
- If the proportion of cresol used exceeds 50 mol%, heat resistance and developability may deteriorate.

Examples of aldehydes used in the synthesis of the specific alkali-soluble resin include formaldehyde, paraformaldehyde, benzaldehyde, furfural, and acetaldehyde, and among these, formaldehyde is particularly preferred. These aldehydes can be used alone or in combination of two or more. The amount of the aldehyde used is preferably 0.7 to 3 mol, more preferably 0.7 to 3 mol, per 1 mol of the total amount of phenols. It is 8 to 1.5 moles.

Examples of the acidic catalyst used in the condensation include inorganic acids such as hydrochloric acid, nitric acid, and sulfuric acid, and organic acids such as formic acid, oxalic acid, and acetic acid. The amount of these acidic catalysts used is usually IXIO-5 to 5X10- per mole of phenol.
It is 1 mole.

In condensation, water is usually used as the reaction medium, but if the phenols used in polycondensation do not dissolve in the aldehyde aqueous solution and the reaction becomes a heterogeneous system from the early stage, a hydrophilic solvent may be used as the reaction medium. You can also use Examples of these hydrophilic solvents include alcohols such as methanol, ethanol, propanol, and butanol, and cyclic ethers such as tetrahydrofuran and dioxane. The amount of these reaction media used is usually 20 to 1,000 parts per 100 parts by weight of reaction materials.
Parts by weight. The reaction temperature for condensation can be adjusted appropriately depending on the reactivity of the reaction raw materials, but is usually 10 to 20
It is 0°C.

Examples of condensation methods include a method in which phenols, aldehydes, and an acidic catalyst are added all at once, and a method in which phenols, aldehydes, etc. are added as the reaction progresses in the presence of an acidic catalyst. I can do it.

After the condensation reaction is completed, the internal temperature is generally lowered to 1
30-230°C and under reduced pressure, e.g. 20-50°C.
Volatile matter is distilled off at about mmHg, and the specific alkali-soluble resin is recovered. After the condensation reaction is completed, the reaction mixture is dissolved in the hydrophilic solvent, and a precipitant such as water, n-hexane, or n-hebutane is added to precipitate the specific alkali-soluble resin, and the precipitate is separated. It can also be collected.

The polystyrene equivalent weight average molecular weight (hereinafter referred to as rMwJ) of the specific alkali-soluble resin used in the present invention is:
2,000 to 20,000.

When Mw is less than 2,000, the heat resistance of the photosensitive resin composition deteriorates, and when it exceeds 20,000, sensitivity decreases.

In addition, the specific alkali-soluble resin has a polystyrene equivalent molecular weight of 6,300 to 27,000, 2,500 to 6,0
When the maximum height values of the peaks in the range of 00 and 150 to 900 are respectively a, b and C, a/b
=0. 2 ~1. 7 and c/b=0.2-2, more preferably a/b=0.2-1
．． 5 and C/b=0.4 to 1.5. If the a/b value exceeds 1.7, developability and sensitivity may deteriorate, and if c/b value exceeds 2, pattern shape, heat resistance, and developability may deteriorate. be.

Examples of the 1,2-quinonediazide compound used in the present invention include 1,2-penzoquinonediazide-4-sulfonic acid ester, 1,2-naphthoquinonediazide-4-
Sulfonic acid ester, 1,2-naphthoquinone diazide
Examples include 5-sulfonic acid esters.

Specifically, 1,2-penzoquinonediazide-4-sulfonic acid ester and 1,2-naphthoquinonediazide-4-sulfonic acid ester of (poly)hydroxybenzene such as p-cresol, resorcinol, birogallol, and phloroglycinol. or 1,2-naphthoquinonediazide-5
-Sulfonic acid ester; 2,4-dihydroxyphenyl-propyl ketone, 2,4-dihydroxyphenyl-101hexyl ketone, 2,4-dihydroxybenzophenone, 2.3.4-trihydroxyphenyl-n- Xyl ketone, 2,3.4-trihydroxybenzophenone, 2,4.6-}rihydroxybenzophenone, 2.3
．． 4.4'-Tetrahydroxybenzophenone, 2
, 3,4.3'-tetrahydroxybenzophenone, 2.2'. 3.4-tetrahydroxy-4'-methylbenzophenone, 2,3,4.4'-tetrahydrocytophenone=3'-methoxybenzophenone, 2.2',
4.4'-Tetrahydroxybenzophenone, 2,2'
, 3,4.6'-Pentahydroxybenzophenone, 2.3.3'. (Poly)hydroxyphenyl alkyl ketones or (poly)hydroxyphenyls such as 4.4',5'-1-hexahedoxybenzophenone, 2.3'4.4'5'6-hexahydroxybenzophenone 1,2-penzoquinonediazide-4-sulfonic acid ester, 1,2-naphthoquinonediazide-4-sulfonic acid ester or 1,2-naphthoquinonediazide-5-sulfonic acid ester of aryl ketone; bis(p-hydroxyphenyl ) methane, bis(2.4=dihydroxydiphenyl)methane, bis(2.3.4-trihydroxyphenyl)methane, 2.2=bis(p-hydroxyphenyl)propane, 2,2-bis( 2,4-dihydroxyphenyl)propane, 2,2-bis(2,3.4-}
Bis[(poly) such as (hydroxyphenyl)propane]
1,2-penzoquinonediazide-4-sulfonic acid ester of hydroxyphenyl]alkane, 1. 2-naphthoquinonediazide-4-sulfonic acid ester or 1,
2-naphthoquinonediazide-5-sulfonic acid ester;
lauryl 3,5-dihydroxybenzoate, 2. 3.
Phenyl 4-4-hydroxybenzoate, 3,4.5-
of (poly)hydroxybenzoic acid alkyl esters or (poly)hydroxybenzoic acid aryl esters such as lauryl trihydroxybenzoate, brobyl 3,4,5-trihydroxybenzoate, phenyl 3,4,5-trihydro6xybenzoate; 1.2-penzoquinonediazide-4-
Sulfonic acid ester, 1,2-naphthoquinonediazide-
4-sulfonic acid ester or 1,2-naphthoquinonediazide-5-sulfonic acid ester; bis(2,5-dihydroxybenzoyl)methane, bis(2.3.4-trihydroxybenzoyl)methane, bis(2 .4.6-}
hydroxybenzoyl)methane, p-bis. (2.5
-dihydroxybenzoyl)benzene, p-bis(2,
3.4-}lihydroxybenzoyl)benzene, p-bis(2,4.6-hlihydroquinebenzoyl)benzene or other bis[(poly)hydroxybenzoyl]alkanes or bis[(poly)hydroxybenzoyl]benzene 1,2-penzoquinonediazide-4-sulfonic acid ester, 1,2-naphthoquinonediazide-4-sulfonic acid ester or 1,2-naphthoquinonediazide-5-sulfonic acid ester; ethylene glycol di(3.5-
(poly)ethylene glycol rouge such as dihydroxybenzoate), polyethylene glycol rouge (3,5-dihydroxybenzoate), and polyethylene glycol rouge (3.4,5-trihydroxybenzoate) [
1,2-penzoquinonediazido-4-sulfonic acid ester, 1,2-naphthoquinonediazide-4-sulfonic acid ester or 1.
Mention may be made of 2-naphthoquinonediazide-5-sulfonic acid ester.

Among the 1,2-quinonediazide compounds, 2,3.4
-}lihydroxybenzophenone-1,2-naphthoquinonediazide-4-sulfonic acid ester, 2,3.4-1
Lyhydroxybenzophenone-1,2-naphthoquinonediazide-5-sulfonic acid ester, 2.4.6-Trihydroxybenzophenone-1,2-naphthoquinonediazide-4-sulfonic acid ester, 2.4.6- }Lihydroxybenzophenone-1,2-naphthoquinone diazide
5-sulfonic acid ester, 2.2'. 4.4'-tetrahydrooxybenzophenone-1.2naphthoquinonediazide-4-sulfonic acid ester, 2.2'. 4.4
' -Tetrahydroxybenzophenone-1,2-naphthoquinonediazide-5-sulfonic acid ester, 2,
3. 4. 3'-tetrahydrooxybenzophenone-1,2-naphthoquinonediazide-4-sulfonic acid ester, 2,3,4.3'-tetrahydrooxybenzophenone-1,2-naphthoquinonediazide-5-sulfonic acid Ester, 2.3,4.4'-tetrahydrooxybenzophenone-1,2-naphthoquinonediazide-4-sulfonic acid ester, 2.3.4.4'-tetrahydrooxybenzophenone-1,2 -Naphthoquinone diazide-
5-sulfonic acid ester, 2.2'. 3. 4-tetrahydrocytophenone-4'-methylbenzophenone-1.2
-naphthoquinone diazide-4-sulfonic acid ester, 2
．． 2'3,4-tetrahydroxy-4'-methylbenzophenone-1,2-naphthoquinone diazide-5-
Sulfonic acid ester, 2,3,4.4'-tetrahydroxy-3'-methoxybenzophenone-1,2-naphthoquinonediazide-4-sulfonic acid ester, 2,3,
4.4'-tetrahydroxy-3'-methoxybenzophenone-1,2-naphthoquinonediazide-5-sulfonic acid ester, 2.2'. 3,4,6'-pentahydroxybenzophenone-1,2-naphthoquinonediazide-4-sulfonic acid ester, 2.2',3,4.6
' -bentahydeoxybenzophenone-1,2-naphthoquinonediazide-5-sulfonic acid ester, 2,3.
3'. 4.4'5'-hexahydroxybenzophenone-1,2-naphthoquinonediazide-4-sulfonic acid ester, 2,3.3',4.4'. 5' monohexahydroxybenzophenone-1,2-naphthoquinonediazide-5-sulfonic acid ester, 2.3' 4.
4'5' 6-Hexahydroxybenzophenone-1,2-naphthoquinonediazide-4-sulfonic acid ester, 2.3'. 1,2-naphthoquinonediazide sulfonic acid esters of polyhydroxybenzophenone such as 4.4'5',6-hexahydroxybenzophenone-1,2-naphthoquinonediazide-5-sulfonic ester are preferred. These 1,2-quinonediazide compounds may be used alone or in combination of two or more.

In addition, the number of 1,2-naphthoquinonediazide sulfonic acid groups bonded to trihydroxybenzophenone, tetrahydroxybenzophenone, pentahydroxybenzophenone, or hexahydroxybenzophenone with or without a substituent ( The condensation ratio (condensation ratio) is 165 to 3 on average for trihydroxybenzophenone, 2 to 4 on average for tetrahydroxybenzophenone, 2.5 to 5 on average for pentahydroxybenzophenone, and 2.5 to 5 on average for pentahydroxybenzophenone. In the case of xybenzophenone, the average number is preferably 3 to 6.

The blending amount of the 1.2-quinonediazide compound is 3 to 50 parts by weight, preferably 5 to 40 parts by weight, based on 100 parts by weight of the specific alkali-soluble resin.

If the amount of the 1.2-quinonediazide compound is too small, it will be difficult to differentiate the solubility of the exposed and unexposed areas in a developer consisting of an alkaline aqueous solution, making patterning difficult; if the amount is too large, A short exposure time cannot completely decompose the added 1,2-quinonediazide compound, making development with a developer consisting of an alkaline aqueous solution difficult.

In the present invention, a sensitizer may be added to the photosensitive resin composition in order to improve the sensitivity to radiation. Examples of these sensitizers include 2H-pyrid (3.
2-b)-1,4-oxazin-3(4H)ones, I
OH-pyrido(3,2-b)(1.4)-benzothiazines, urazoles, hydantoins, barbiturates, glycine anhydrides, 1-hydroxybenzotriazoles, alloxanes, maleimides, etc. . The blending amount of these sensitizers is usually 100 parts by weight or less per 100 parts of the 1,2-quinonediazide compound.

In addition, in the present invention, the photosensitive resin composition has coating properties,
For example, a surfactant may be blended to improve striations and the developability of exposed areas after resist layer formation. Examples of surfactants include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, and polyoxyethylene oleyl ether, polyoxyethylene octyl phenyl ether, and polyoxyethylene nonyl phenyl ether. Polyoxyethylene alkyl ethers, polyethylene glycol dilaurate,
Nonionic surfactants such as polyethylene glycol dialkyl esters such as polyethylene glycol distearate, FTOP EF301, EF30B, EF
352 (manufactured by Shin-Akita Kasei Co., Ltd.), Megafac F171,
F172, F173 (manufactured by Dainippon Ink), Florado FC430, FC431 (manufactured by Sumitomo 3M),
Asahi Guard AG710, Surflon S-382, SC
101, SC102, SC103, SCIO4, SC1
05, SC106 (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 Boliflow-No. 75, No. 95 (manufactured by Kyoeisha Yushi Kagaku Kogyo Co., Ltd.). The blending amount of these surfactants is usually 2% by weight or less based on the solid content of the composition.

Furthermore, in the present invention, the photosensitive resin composition includes a dye, for example, 1.7-bis(3-methoxy4-hydroxyphenyl)-, which makes the latent image in the exposed area visible and reduces the effect of halation during exposure. 1,6-hebutadiene-
Dyes having a β-diketone structure such as 3,5-dione,
5-hydroxy-4-(4-methoxyphenylazo)-
Dyes having a pyrazole or imidazole structure such as 3-methyl-1-phenylpyrazole, pigments, and adhesion aids for improving adhesion can also be blended, and if necessary, storage stabilizers, Antifoaming agents and the like can also be added.

In the present invention, as a method for forming a resist layer on a substrate such as a silicon wafer, predetermined amounts of the specific alkali-soluble resin, 1,2-quinonediazide compound, and various compounding agents as necessary are added to a solid content concentration of 20%. ~4
For example, the pore size is 0.0% by weight.
After filtering through a filter of about 2 μm, it is applied by spin coating, flow coating, roll coating, etc. so that the dry film thickness is usually 0.5 to 4 μm, and then dried.

Examples of solvents used in this case include glycol ethers such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether, ethylene glycol alkyl ether acetates such as methyl cellosolve acetate and ethyl cellosolve acetate, diethylene glycol monomethyl ether, and diethylene glycol monoethyl ether. Diethylene glycols such as propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol alkyl ether acetate such as brobylene glycol propyl ether acetate,
Aromatic hydrocarbons such as toluene and xylene, ketones such as methyl ethyl ketone and cyclohexanone, methyl 2-hydroxyprobionate, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxy acetate, oxy Ethyl acetate, 2-
Methyl hydroxy-3-methylbutanoate, methyl-
Esters such as 3-methoxybutyl acetate, 3-methyl-3-methoxybutylbutylbionate, 3-methyl-3-methoxybutylbutyrate, ethyl acetate, and butyl acetate can be used. These solvents can be used alone or in combination of two or more.

Furthermore, benzyl ethyl ether, dihexyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, acetonyl acetone, isophorone, caproic acid, cabrylic acid, 1-octanol, 1-nonanol, benzyl alcohol, benzyl acetate, ethyl benzoate, oxalic acid. Adding high boiling point solvents such as diethyl, diethyl maleate, γ-butyrolactone, ethylene carbonate, propylene carbonate, phenyl cellosolve acetate, N,N-dimethylformamide, N-methyl-2-pyrrolidone, dimethylbenzimidazolidinone. You can also do it.

After forming the resist layer on the substrate, the resist layer is exposed through a pattern mask, preferably through a reticle of a reduction projection exposure machine. The wavelength of the light that exposes the resist layer is 3
00-380 nm, preferably 350-380 nm
m, and the exposure amount is usually 25 to 1,000 mJ/ct
l, preferably 50 to 500 mJ/ci.

As a developer for developing the resist layer after exposure,
For example, inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, primary amines such as ethylamine and n-probylamine, diethylamine, di-n-propylamine, etc. Secondary amines such as bilamin, tertiary amines such as triethylamine, methyldiethylamine,
Alcohol amines such as dimethylethanolamine and triethanolamine, quaternary ammonium salts such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, choline, or pyrrole, piperidine, 1,8-diazabisic acid (5,4.0) -7-
undecene, 1.5-diazabicyclo(4.3.0)-
Concentration of 1 to 1 by dissolving cyclic amines such as 5-nonane
A 10% by weight aqueous alkaline solution is used. Furthermore, a suitable amount of a water-soluble organic solvent, such as alcohols such as methanol and ethanol, or a surfactant may be added to the developer.

Furthermore, in the present invention, in order to further improve the pattern shape, a photosensitive resin composition is applied onto the substrate, prebaked and exposed, and then heated.
It can also be developed. After development, rinsing is usually performed with water or the like.

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

In addition, the polystyrene equivalent molecular weight in the synthesis example is based on Toyo Soda GPC columns (2 G2000Hs, G300
0H6 one, G4000H6 one), flow rate 1
．． Measurement was carried out by gel permeation chromatography (GPC) using monodisperse polystyrene as a standard, under analysis conditions of 5 ml/min, elution solvent tetrahydrofuran, and column temperature 40°C.

Synthesis Example 1 In a separable flask equipped with a stirrer, a condenser, and a thermometer, 78.8 g (0.729 mol) of m-cresol and 20.3 g (
0.149 mol), 121 g (1.49 mol) of a 37% by weight formaldehyde aqueous solution (formalin), and 1.5 g (0.0119 mol) of oxalic acid dihydrate, and immersed the separable flask in an oil bath. After condensing for 1 hour while keeping the internal temperature at 100°C and stirring, 19.7 g (0.182 mol) of m-cresol and 2,3,5
- 81.2 g (0.596 mol) of trimethylphenol was added and condensation was further carried out for 2.5 hours to synthesize a specific alkali-soluble resin. After the reaction, the temperature of the oil bath was increased to 180℃.
℃ and at the same time increase the pressure inside the reaction vessel to 30-5 Qmm.
The pressure was reduced to Hg to remove water, oxalic acid, unreacted formaldehyde, m-cresol, 2,3.5-trimethylphenol, and the like. Next, the dissolved specific alkali-soluble resin was returned to room temperature and recovered (hereinafter, this specific alkali-soluble resin will be referred to as "resin A"). When resin A was dissolved in tetrahydrofuran and the Mw was measured, it was found to be 4.
,900.

Synthesis Example 2 In a separable flask similar to that in Synthesis Example 1, 18.8 g (0.174 mol) of m-cresol, 84.9 g (0.695 mol) of 3,5-xylenol, and 126.9 g (1 mol) of formalin were added. .563 mol) and oxalic acid.
Charge 0.142 g (0.00113 mol) of dihydrate, immerse the separable flask in an oil bath, and bring the internal temperature to 100°C.
After condensing for 30 minutes with stirring, m-
75.1 g (0.695 mol) of cresol and 3,
21.2 g (0.174 mol) of 5-xylenol was added, and condensation was further carried out for 100 minutes to synthesize an alkali-soluble resin. After the reaction, the temperature of the oil bath was raised to 180°C, and at the same time the pressure inside the reaction vessel was reduced to 30-50 mmHg, and water, oxalic acid, unreacted formaldehyde, m
-Cresol and 3,5-xylenol were removed. Next, the molten alkali-soluble resin was returned to room temperature and recovered (hereinafter, this specific alkali-soluble resin will be referred to as "resin B"). Resin B was dissolved in tetrahydrofuran and its Mw was measured and found to be 3,500.

Synthesis Example 3 Into a separable flask similar to that in Example 1, 82.4 g (0.763 mol) of m-cresol, 2,3.5
-Trimethylphenol 11.8g (0.087mol)
, p-cresol 37. 6g (0.348 mol),
Charge 127.0 g (1.565 mol) of formalin and 1.578 g (0.0125 mol) of oxalic acid dihydrate, immerse the separable flask in an oil bath, and maintain the internal temperature at 100°C. After condensation for 60 minutes with stirring, 20.6 g m-cresol (<0.191 mol)
and 2, 3. 5-trimethylphenol 47
．． 3 g (0.348 mol) was added and condensation was further carried out for 120 minutes to synthesize a specific alkali-soluble resin. After the reaction, the temperature of the oil bath was raised to 180°C, and at the same time the pressure inside the reaction vessel was reduced to 30-50 miHg, and water, oxalic acid, unreacted formaldehyde, m-cresol, and p-
Cresol, 2,3,5-trimethylphenol, etc. were removed. Next, the molten specific alkali-soluble resin was returned to room temperature and recovered (hereinafter, this specific alkali-soluble resin is referred to as "resin C"). Resin C was dissolved in tetrahydrofuran and its Mw was measured and found to be 5,200.

Synthesis Example 4 In a separable flask similar to that in Synthesis Example 1, 17.8 g (0.165 mol) of m-cresol, 53.4 g (0.438 mol) of 3,5-xylenol, and 44.4 g of p-cresol were added. (0.411 mol), formalin 1
37.3 g (1.692 mol) and 0.3 g (1.692 mol) of oxalic acid dihydrate. 14.6g (0.00116 mol)
and soak the separable flask in an oil bath to bring the internal temperature to 1.
After condensation was carried out for 45 minutes while maintaining the temperature at 00°C with stirring, 71.0 g (0.657 mol) of m-cresol and 13.4 g (0.110 mol) of 3,5-xylenol were added, and the mixture was further condensed for 60 minutes. A specific alkali-soluble resin was synthesized by condensation. After the reaction, the temperature of the oil bath was increased to 180℃.
℃ and at the same time increase the pressure inside the reaction vessel to 30-50n+.
Reduce pressure to mHg and add water, oxalic acid, unreacted formaldehyde, m-cresol, p-cresol and 3,5
-Removed xylenol, etc. Next, the molten specific alkali-soluble resin is returned to room temperature and recovered (hereinafter, this specific alkali-soluble resin will be referred to as "resin D"). Resin D was dissolved in tetrahydrofuran and its Mw was measured and found to be 4,200.

Synthesis Example 5 In a separable flask similar to that in Synthesis Example 1, 56.7 g (0.524 mol) of m-cresol, 2,3.5
-1-trimethylphenol 17.8g (0.131mol)
, 20.0 g (0.164 mol) of 2,5-xylenol, 119.6 g (1.47 mol) of formalin, and 1.49 g (0.0118 mol) of oxalic acid dihydrate were placed in a separable flask. After condensation was carried out for 90 minutes while keeping the internal temperature at 100°C and stirring in an oil bath, 14.2 g (0.131 mol) of m-cresol was added.
, 2, 3,5-trimethylphenol 71.3g
(0.523 mol), 2.5-xylenol 20.
0g (0.164 mol) was added and condensation was further carried out for 240 minutes to synthesize a specific alkali-soluble resin. After the reaction, the temperature of the oil bath was raised to 180°C, and at the same time the pressure inside the reaction vessel was reduced to 30-50 mmHg, and water, oxalic acid,
Unreacted formaldehyde, m-cresol, 2,5-
Xylenol, 2,3.5-1-limethylphenol, etc. were removed. Next, the molten specific alkali-soluble resin was returned to room temperature and recovered (hereinafter, this specific alkali-soluble resin is referred to as "resin E"). Resin E was dissolved in tetrahydrofuran and its Mw was measured and found to be 3,300.

Synthesis Example 6 In a separable flask similar to that in Synthesis Example 1, 30 g (0.277 mol) of m-cresol, 170 g (1.572 mol) of p-cresol, and 150 g of formalin were added.
(1.849 mol) and 0.23 oxalic acid dihydrate
3 g (0.00185 mol) was charged, the separable flask was immersed in an oil bath, the internal temperature was maintained at 100° C., and condensation was carried out for 280 minutes with stirring to synthesize a resin. After the reaction, the oil bath was raised to 180°C, and at the same time the pressure inside the reaction vessel was reduced to 30 to 50 mmHg to remove water, oxalic acid, unreacted formaldehyde, m-cresol, and p-cresol. Next, the molten resin was returned to room temperature and collected (hereinafter, this resin will be referred to as "resin F"). Resin F was dissolved in tetrahydrofuran and ``i'' was measured and found to be 3,100.

Example 1 100 g of resin and a condensate of 1 mol of 2,3,4,4'-tetrahydrooxybenzophenone and 3.6 mol of 1,2-naphthoquinonediazide-5-sulfonic acid chloride (
After dissolving 20 g of ``1,2-quinonediazide compound (I)'' in 310 g of ethyl cellosolve acetate, it was filtered through a membrane filter with a pore size of 0.2 μm.
A photosensitive resin composition was prepared. The obtained solution was applied onto a silicon wafer having a silicon oxide film using a spinner, and then heated at 90°C on a hot plate for 2 hours.
A resist layer with a thickness of 1.2 μm was formed by bre-baking for 1 minute, and exposed for 0.310 seconds with a Nikon reduction projection exposure machine (light source 365 nm, numerical aperture of lens 0.45), and then exposed with 2.0 μm of tetramethylammonium hydroxide. When developed at 25°C for 60 seconds using a 4% by weight aqueous solution, rinsed with water, and dried, lines and spaces were formed on the wafer.
．． A resist pattern with a thickness of 45 μm could be formed.

Next, the following tests were conducted.

Resolution: The dimension of the smallest resist pattern that is resolved when exposed at the optimum exposure time was measured.

Remaining film rate: The thickness of the remaining pattern at the optimum exposure time was divided by the thickness of the applied resist layer, this value was multiplied by 100, and expressed in units of %.

Developability: The degree of scum and development residue was examined.

Heat resistance: A wafer with a resist pattern formed thereon was placed in a clean oven, and the temperature at which the pattern began to collapse was measured.

Pattern shape: Where X is the width of the top surface of a 0.5 μm resist pattern and y is the width of the bottom surface, those with an x/y value of 0.85 to 1.01 were considered good.

Note that the optimum exposure time means that exposure is performed by changing the exposure time when forming a resist pattern, then development is performed using a 2.4% by weight aqueous solution of tetramethylammonium hydroxide at 25°C for 60 seconds, and the resist pattern is rinsed with water. After drying, a resist pattern was formed on the wafer, and a 0.6 μm line and space pattern (ILIS) was formed.
This represents the exposure time for forming the 1:1 ratio. The results are shown in Table-1.

Examples 2 to 10 and Comparative Example 1 Except for using a photosensitive resin composition in which the types and amounts of the specific alkali-soluble resin, 1,2-quinonediazide compound, light absorber, and solvent were as shown in Table 1. A resist pattern was formed in the same manner as in Example 1. However, in Example 10, the substrate was heated on a hot plate at 110° C. for 1 minute before development. Then, in the same manner as in Example 1, resolution, residual film rate, developability, heat resistance, and pattern shape were measured. The results are shown in Table-1.

In addition, in Table 1, 1,2-naphthoquinonediazide compound (■) is 2, 3, 4. A condensate of 1 mol of 4'-tetrahydrooxybenzophenone and 3.0 mol of 1,2-naphthoquinonediazide-4-sulfonic acid chloride is prepared as 1,2-naphthoquinonediazide compound (2).
, 4.4'-tetrahydroxy-3'-methoxybenzophenone 1 mol and 1,2-naphthoquinonediazide-5
- 1.2 mol of condensate with 3.0 mol of sulfonic acid chloride
- Naphthoquinonediazide compound (2) is a condensate of 1 mole of 2,3.4-trihydroxybenzophenone and 2.5 moles of 1,2-naphthoquinonediazide-5-sulfonic acid chloride. V is 2
．． A condensate of 1 mole of 2',3,4.6'-pentahydroxybenzophenone and 4 moles of 1,2-naphthoquinonediazide-5-sulfonic acid chloride is prepared as 1,2-naphthoquinonediazide compound (2). 3.3', 4.4'
, 1 mole of 5'hexahydroxybenzophenone and 1,
2-naphthoquinonediazide-5-sulfonic acid chloride 4
．． This shows a condensate with 5 moles.

Example 11 The same procedure as in Example 1 was carried out except that 2.5 g of 1,7-bis(3-methoxy4-hydroxyphenyl)-1,6-hebutadiene-3,5-dione, which is a light absorbing agent, was added. A solution of a photosensitive resin composition was prepared in the same manner as in Example 1.

The obtained solution was spin-coated onto a silicon wafer having a step structure of 0.6 μm on which a 0.2 μm thick aluminum layer was vapor-deposited, and then prebaked on a hot plate at 90° C. for 2 minutes to form a 1.5 μm thick aluminum layer. A resist layer of .3 μm was formed, exposed for 0.410 seconds using a Nikon reduction projection exposure machine (light source 365 nm, lens numerical aperture 0.45), and then using a 2.4% by weight aqueous solution of tetramethylammonium hydroxide. After developing at 25°C for 60 seconds, rinsing with water, and drying, there were no lines and spaces on the wafer.
A resist pattern with a thickness of 45 μm could be formed. Next, in the same manner as in Example 1, the resolution, residual film rate,
Developability, heat resistance, and pattern shape were measured. The results are shown in Table-1.

Example 12 In Example 1, the light absorbing agent 5-hydroxy-4-
A photosensitive resin composition was prepared in the same manner as in Example 1 except that (4-methoxyphenylazo)-3-methyl-1-phenylvirazole was added. A resist pattern was formed in the same manner as in Example 11 (2) except that the obtained photosensitive resin composition was used. Then, in the same manner as in Example 1, resolution, residual film rate, developability, heat resistance, and pattern shape were measured. The results are shown in Table-1.

The following margin [Effects of the Invention] The method of the present invention is excellent in sensitivity, resolution, residual film rate, and developability in forming a resist pattern, and is also excellent in the pattern shape and heat resistance of the resulting resist pattern.

Claims (1)

[Claims] On the substrate, (1) m-cresol 20 to 80 mol%,
p-cresol 0 to 50 mol%, m-cresol selected from compounds represented by the following general formula (I) and p-cresol
- at least one compound other than cresol 20-80
Alkali-soluble resin obtained by condensing phenols consisting of mol% and aldehydes, and (2) 1
, a pattern formation process comprising the steps of applying a photosensitive resin composition containing a 2-quinonediazide compound, drying it to form a resist layer, and exposing the resist layer to light with a wavelength of 300 to 380 nm. Method. General formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) [In the formula, R^1 to R^3 may be the same or different, and are hydrogen atoms, hydroxyl groups, R^4, OR^4, or COOR＾4
(R^4 represents an alkyl group having 1 to 4 carbon atoms). ]