JPH11322874A - Alkali soluble novolak resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an alkali soluble novolac resin preferably used for preparing a radiation sensitive resin composition of a positive type suitable as a positive type resist for preparing highly integrated circuits having high sensitivities and good developing properties, capable of resolving resist patterns having <1 μm line breadth and good in dry-etching resistance, wet-etching resistance and heat resistance. SOLUTION: This alkali soluble novolak resin is obtained by condensing (A) cresol essentially comprising 30-70 mole % of m-cresol and 70-30 mole % of p-cresol with a carbonyl compound. The condensation reaction is carried out in a method to add cresol in accordance with the progress of the reaction. (B) when (a), (b) and (c) are maximum heights in molecular weights, expressed in terms of polystyrene measured by a gel permeation chromatography using a monodisperse polystyrene, in the range of 6,300-25,000, 2,500-6,000 and 150-900, they satisfy the following equations: a/b=0.4-1.5 and c/b=0.5-2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an alkali-soluble novolak resin. More specifically, a positive-type radiation-sensitive material that is sensitive to radiation such as ultraviolet rays, far ultraviolet rays, X-rays, electron beams, molecular beams, γ-rays, synchrotron radiation, and proton beams, and is particularly suitable as a resist for producing highly integrated integrated circuits. The present invention relates to an alkali-soluble novolak resin suitably used for preparing a hydrophilic resin composition.

[0002]

2. Description of the Related Art Conventionally, as a resist for producing an integrated circuit, a negative resist in which a bisazide compound is mixed with a cyclized rubber and a positive resist in which a 1,2-quinonediazide compound is mixed with an alkali-soluble resin are known. . In a negative resist, the bisazide compound removes nitrogen by irradiation with ultraviolet light to form nitrene and cross-links the cyclized rubber three-dimensionally. However, the cross-linking does not completely cure the UV-irradiated part, and therefore, in the negative resist, the swelling of the resist pattern in the developing solution is large. However, there is a disadvantage that the resolution of the resist pattern is poor.

On the other hand, since a positive resist contains an alkali-soluble resin and an alkali-insoluble 1,2-quinonediazide compound, it hardly dissolves in an alkaline aqueous solution in a developing solution and hardly swells. That is, in the positive resist, the 1,2-quinonediazide compound in the UV-irradiated portion changes to indenecarboxylic acid, and even when the resist is developed with a developing solution composed of an alkaline aqueous solution, the change in the non-irradiated portion serving as the resist pattern is extremely small. A resist pattern with high resolution that is faithful to the pattern of the mask can be obtained. Therefore, in recent years, where high integration of integrated circuits is required, positive type resists having excellent resolution are frequently used, and with the improvement of the integration degree of integrated circuits, the resolution of the positive type resist is further improved. There is a strong demand. For example, in the ultraviolet exposure method, a thin film of a positive resist applied to a wafer is exposed through a mask to form a latent image and then developed with an alkaline aqueous solution. Unless developed quickly, it becomes difficult to obtain a resist pattern faithful to the mask.

Further, in a conventional positive resist, if an attempt is made to obtain a narrow resist pattern having a resist pattern interval (hereinafter referred to as “line width”) of 1 μm or less, the exposed portion is not completely developed and the resist remains. There is a problem that the resist adheres to the substrate as a scum-like residue.
When a fine resist pattern is formed by increasing the exposure amount, the size of a larger pattern tends to be smaller than the design size. Further, in the conventional positive resist, there is a problem that the dimension of the resist pattern becomes wider as it is closer to the substrate because the contrast is low.

Further, in the conventional positive type resist, the size of the resist pattern greatly changes due to a slight change in the amount of exposure, or when the exposure is performed by a reduction projection type exposure apparatus used for manufacturing an integrated circuit, the focus is slightly reduced. There is a problem that the size and the cross-sectional shape of the resist pattern greatly fluctuate due to the fluctuation. Further, when the reduced projection exposure method is used, there is a problem that the throughput is lower than when the conventional mask contact method is used, that is, the exposure time per wafer is longer.

Further, when a resist pattern is transferred to a substrate in a dry etching step, the resist is consumed, and the size of the resist pattern fluctuates greatly. Therefore, accurate transfer is not performed, and the wafer is heated during the dry etching. As a result, the resist pattern may be thermally deformed, which causes a problem that dry etching cannot be performed efficiently. In addition, the conventional positive type resist may have a problem in the adhesiveness of the substrate to the resist. In this case, when wet etching is performed, the etching solution penetrates between the substrate and the resist, so that a horizontal direction is caused. There is a problem that etching is further increased.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide an alkali-soluble novolak resin which is particularly preferably used for preparing a positive-working radiation-sensitive composition. Another object of the present invention is to provide a high-integration method which has high sensitivity, good developability, can resolve a resist pattern having a line width of 1 μm or less, and has good dry etching resistance, wet etching resistance and heat resistance. Another object of the present invention is to provide an alkali-soluble novolak resin suitably used for preparing a positive radiation-sensitive resin composition suitable as a positive resist for producing an integrated circuit. Still other objects and advantages of the present invention will become apparent from the following description.

[0008]

According to the present invention, the above objects and advantages of the present invention are as follows: (A) m-cresol 30
It is obtained by a condensation reaction of cresol substantially consisting of 70 mol% and 70 to 30 mol% of p-cresol with a carbonyl compound, wherein the condensation reaction is carried out by a method of adding cresol with the progress of the reaction, and (B) The maximum heights in the respective ranges of 6300-25000, 2500-6000 and 150-900 in terms of polystyrene determined by gel permeation chromatography using monodisperse polystyrene as a standard are a and b, respectively. And c, wherein a / b = 0.4 to 1.5 and c / b = 0.5 to 2 respectively.

The alkali-soluble novolak resin of the present invention is obtained by condensing cresol containing m-cresol and p-cresol with a carbonyl compound. m-
Usage ratio of cresol and p-cresol (mol%)
Is 30-70 / 70-30, preferably 40-60 /
60 to 40. When the use ratio of m-cresol exceeds 70 mol%, resolution and developability deteriorate. When the use ratio is less than 30 mol%, sensitivity,
Resolution and developability decrease. In addition, this use ratio is a use ratio of the raw material at the time of synthesizing the novolak resin.

Further, alkali-soluble novolak resins of the present invention, Toyo Soda made GPC column (G2000H ₆ 2
This, G3000H ₆ 1 present, using G4000H ₆ 1 present), elution solvent tetrahydrofuran, flow rate 1.5m solvent
1 / min, under the analysis conditions of a column temperature of 40 ° C., the molecular weight in terms of polystyrene determined by the GPC method using monodispersed polystyrene as a standard is 6300-25000, 2500-600.
If the maximum height values in the respective ranges of 0 and 150 to 900 are a, b and c, respectively, a / b = 0.4
~ 1.5 and c / b = 0.5-2, preferably a / b =
Novolak resins in the ranges of 0.6 to 1.4 and c / b = 0.5 to 1.5. By using this alkali-soluble novolak resin, a radiation-sensitive resin composition having excellent resolution, sensitivity, developability, heat resistance, dry etching resistance and wet etching property can be obtained as compared with conventional alkali-soluble novolak resins. The value of a / b is 0.
When it is less than 4 or more than 1.5, and when the value of c / b is less than 0.5 or more than 2, it becomes difficult to resolve a resist pattern of 1 μm or less.

The alkali-soluble novolak resin of the present invention is synthesized by condensing the mixed cresol with a carbonyl compound in the presence of an acid catalyst. The carbonyl compound used in the present invention is represented, for example, by the following general formula (I).

[0012]

Embedded image Wherein R ₁ and R ₂ are the same or different, a hydrogen atom,
It means an alkyl group, an aryl group, an alkenyl group or an aralkyl group. ]

The alkyl group of R ₁ and R ₂ in the general formula (I) includes, for example, a methyl group, an ethyl group, a propyl group and a butyl group, and the aryl group includes
For example, phenyl group, toluyl group, cumenyl group and the like, alkenyl group such as vinyl group, propenyl group, allyl group, butenyl group and the like, and aralkyl group such as benzyl group, phenethyl group, cumyl group and the like. Can be.

Examples of the carbonyl compound include formaldehyde, paraformaldehyde, acetaldehyde, propylaldehyde, benzaldehyde, phenylacetaldehyde, α-phenylpropylaldehyde, β-phenylpropylaldehyde, toluylbenzaldehyde, mesitylbenzaldehyde, phenethylbenzaldehyde, o-hydroxy Benzaldehyde, m
-Hydroxybenzaldehyde, p-hydroxybenzaldehyde, o-chlorobenzaldehyde, m-chlorobenzaldehyde, p-chlorobenzaldehyde, o-
Nitrobenzaldehyde, m-nitrobenzaldehyde, p-nitrobenzaldehyde, o-methylbenzaldehyde, m-methylbenzaldehyde, p-methylbenzaldehyde, p-ethylbenzaldehyde, pn
-Butylbenzaldehyde, acrolein, crotonaldehyde, cinnamaldehyde, acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone,
Methyl phenyl ketone, methyl benzyl ketone and the like, among these compounds, formaldehyde, acetaldehyde, benzaldehyde, p-hydroxybenzaldehyde, acrolein, acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, methyl phenyl ketone, methyl benzyl ketone and the like Is preferred.

The carbonyl compound may be used alone or in combination of two or more.
The above can be mixed and used. This carbonyl compound
The amount of the compound is preferably based on 1 mole of the mixed cresol.
Is from 0.7 to 3 mol, particularly preferably from 0.7 to 2 mol.
You. Acid catalysts include, for example, inorganic acids such as hydrochloric acid, nitric acid, and sulfuric acid.
Organic acids such as acid, formic acid, oxalic acid and acetic acid can be mentioned. Acid catalyst
Is used in an amount of 1 × 10 ^-Four~
5 × 10^-1Molar is preferred.

In the condensation reaction, water is usually used as a reaction medium, but a hydrophilic solvent can also be used. In this case, examples of the hydrophilic solvent used 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 the total amount of mixed cresol and carbonyl compound, 1
20 to 1000 parts by weight per 00 parts by weight is preferred.

The reaction temperature of the condensation reaction can be appropriately adjusted according to the reactivity between the mixed cresol and the carbonyl compound, but is usually from 10 to 200 ° C., preferably from 70 to 1 ° C.
50 ° C. As a reaction method for obtaining the alkali-soluble novolak resin, a method is employed in which cresol is added to a carbonyl compound and an acid catalyst with the progress of the reaction to cause a reaction. In the method of reacting by adding cresol with the progress of the reaction, in order to produce the alkali-soluble novolak resin more reproducibly and stably, the total amount of p-cresol and a part of m-cresol,
It is preferable to adopt a method in which a carbonyl compound and an acid catalyst are charged and polymerized, and then the remaining m-cresol is added as the reaction proceeds to cause a reaction. After completion of the condensation reaction, in order to remove unreacted substances, acid catalyst and reaction medium to be present in the system, the internal temperature is generally raised to 130 to 230 ° C., and volatile components are distilled off under reduced pressure. The alkali-soluble novolak resin is cast on a steel belt or the like to recover the alkali-soluble novolak resin.However, a method is used in which the volatile components are distilled off, cooled, dissolved in a solvent, and recovered. Can also.

The alkali-soluble novolak resin of the present invention is used together with a 1,2-quinonediazide compound to give a positive radiation-sensitive composition. The 1,2-quinonediazide compound is not particularly limited.
Benzoquinonediazide-4-sulfonic acid ester, 1,
2-naphthoquinonediazide-4-sulfonic acid ester,
1,2-naphthoquinonediazide-5-sulfonic acid ester and the like. Specifically, p-cresol-1,2
1,2 of (poly) hydroxybenzene such as benzoquinonediazide-4-sulfonic acid ester, resorcinol-1,2-naphthoquinonediazide-4-sulfonic acid ester, pyrogallol-1,2-naphthoquinonediazide-5-sulfonic acid ester -Quinonediazidesulfonic acid esters, 2,4-dihydroxyphenyl-propyl ketone-1,2-benzoquinonediazide-4-sulfonic acid ester, 2,4-dihydroxyphenyl-n-hexylketone-1,2-naphthoquinonediazide-4 -Sulfonic acid ester, 2,4-dihydroxybenzophenone-
1,2-naphthoquinonediazide-5-sulfonic acid ester, 2,3,4-trihydroxyphenyl-n-hexyl ketone-1,2-naphthoquinonediazide-4-sulfonic acid ester, 2,3,4-trihydroxybenzophenone -1,2-naphthoquinonediazide-4-sulfonic acid ester, 2,3,4-trihydroxybenzophenone-1,
2-naphthoquinonediazide-5-sulfonic acid ester,
2,4,6-trihydroxybenzophenone, -1,2-
Naphthoquinonediazide-4-sulfonic acid ester, 2,
4,6-trihydroxybenzophenone-1,2-naphthoquinonediazide-5-sulfonic acid ester, 2,2 ′,
4,4'-tetrahydroxybenzophenone-1,2-naphthoquinonediazide-5-sulfonic acid ester, 2,3,
4,4'-tetrahydroxybenzophenone-1,2-naphthoquinonediazide-5-sulfonic acid ester,
2 ', 4,4'-tetrahydroxybenzophenone-1,
2-naphthoquinonediazide-4-sulfonic acid ester,
2,3,4,4'-tetrahydroxybenzophenone-1,
2-naphthoquinonediazide-4-sulfonic acid ester,
2,2 ', 5,6-tetrahydroxybenzophenone-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'-pentahydroxybenzophenone-1,2-naphtho Quinonediazide-5-sulfonic acid ester, 2 ', 3,4,5,6'-pentahydroxybenzophenone-1,2-naphthoquinonediazide-5-sulfonic acid ester, 2,3,3', 4,4 ', 5 '-Hexahydroxybenzophenone-1,2-naphthoquinonediazido-4-sulfonic acid ester, 2,3,3', 4,4 ',
5′-hexahydroxybenzophenone-1,2-naphthoquinonediazide-5-sulfonic acid ester, 2,3 ′,
4,4 ', 5', 6-hexahydroxybenzophenone-
(Poly) hydroxy such as 1,2-naphthoquinonediazide-4-sulfonic acid ester, 2,3 ', 4,4', 5 ', 6-hexahydroxybenzophenone-1,2-naphthoquinonediazide-5-sulfonic acid ester 1,2-quinonediazidosulfonic acid esters of phenylalkylketone or (poly) hydroxyphenylarylketone,
Bis (p-hydroxyphenyl) methane-1,2-naphthoquinonediazide-4-sulfonic acid ester, bis (2,4-dihydroxyphenyl) methane-1,2-naphthoquinonediazide-5-sulfonic acid ester, bis (2, 3,4-trihydroxyphenyl) methane-1,2
-Naphthoquinonediazide-5-sulfonic acid ester,
2,2-bis (p-hydroxyphenyl) propane-1,
2-naphthoquinonediazide-4-sulfonic acid ester,
2,2-bis (2,4-dihydroxyphenyl) propane-1,2-naphthoquinonediazide-5-sulfonic acid ester, 2,2-bis (2,3,4-trihydroxyphenyl) propane-1,2- 1,2-quinonediazidosulfonic acid esters of bis [(poly) hydroxyphenyl] alkane, such as naphthoquinonediazide-5-sulfonic acid ester, lauryl-1,2,3,5-dihydroxybenzoate
-Naphthoquinonediazide-4-sulfonic acid ester,
Phenyl-1,2,3,4-trihydroxybenzoate-1,2-
Naphthoquinonediazide-5-sulfonic acid ester, 3,
Propyl 4,5-trihydroxybenzoate-1,2-naphthoquinonediazide-5-sulfonate 3,4,5
1,2-quinonediazidesulfonic acid esters of (poly) hydroxybenzoic acid alkyl esters or (poly) hydroxybenzoic acid arylesters such as phenyl-1,2-naphthoquinonediazide-5-sulfonic acid ester of phenyl-1,2-naphthoquinonediazide-5-sulfonate, bis (2,5-dihydroxybenzoyl) methane-1,2-naphthoquinonediazide-4-sulfonic acid ester, bis (2,3,4-trihydroxybenzoyl) methane-1,2-naphthoquinonediazide-5-sulfonic acid ester, Bis (2,4,6-trihydroxybenzoyl) methane-1,2-naphthoquinonediazide-5-sulfonic acid ester, p-bis (2,5
-Dihydroxybenzoyl) benzene-1,2-naphthoquinonediazide-4-sulfonic acid ester, p-bis (2,3,4-trihydroxybenzoyl) benzene-
1,2-naphthoquinonediazide-5-sulfonic acid ester, p-bis (2,4,6-trihydroxybenzoyl)
1,2-quinonediazidosulfonic acid esters of bis [(poly) hydroxybenzoyl] alkane or bis [(poly) hydroxybenzoyl] benzene such as benzene-1,2-naphthoquinonediazide-5-sulfonic acid ester, ethylene glycol-di (3,5-dihydroxybenzoate) -1,2-naphthoquinonediazide-5
-Sulfonic acid ester, polyethylene glycol-di (3,4,5-trihydroxybenzoate) -1,2-
1,2-quinonediazidesulfonic acid esters of (poly) ethylene glycol-di [(poly) hydroxybenzoate] such as naphthoquinonediazide-5-sulfonic acid ester. These 1,2-quinonediazide compounds are used alone or in combination of two or more.

The amount of the 1,2-quinonediazide compound is usually 5 to 100 parts by weight, preferably 1 to 100 parts by weight of the alkali-soluble novolak resin.
0 to 50 parts by weight. When the amount is less than 5 parts by weight, the amount of indenecarboxylic acid generated by the absorption of the 1,2-quinonediazide compound is small, so that patterning is difficult. In a short time, all the 1,2-quinonediazide compounds in the irradiated area cannot be decomposed by short-time irradiation, and it becomes difficult to develop with a developing solution composed of an alkaline aqueous solution.

A sensitizer can be added to the above composition in order to improve the sensitivity as a resist. These sensitizers include, for example, 2H-pyrido [3,2-
b] -1,4-oxazine-3 [4H] ones, 10H
-Pyrido [3,2-b] [1,4] -benzothiazines,
Examples thereof include urazoles, hydantoins, barbituric acids, glycine anhydrides, 1-hydroxybenzotriazoles, alloxanes, and maleimides. The amount of the sensitizer is usually 100 parts by weight or less, preferably 4 to 60 parts by weight, based on 100 parts by weight of the 1,2-quinonediazide compound.

Further, a surfactant or the like may be added to the above composition in order to improve coatability, for example, developability of a radiation-irradiated portion after formation of a striation or a dried coating film. Examples of the surfactant include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, and polyoxyethylene oleyl ether; and polyoxyethylene alkyl phenols such as polyoxyethylene octyl phenol ether and polyoxyethylene nonyl phenol ether. Nonionic surfactants such as ethers, polyethylene glycol dialkyl ethers such as polyethylene glycol dilaurate and polyethylene glycol distearate, F-top EF301, EF30
3, EF352 (manufactured by Shin-Akita Kasei Co., Ltd.), Megafac F171 and F173 (manufactured by Dainippon Ink Co., Ltd.), Florado FC430, FC431 (Sumitomo 3M Limited)
Asahi Guard AG710, Surflon S-38
2, SC101, SC102, SC103, SC10
4. Fluorinated surfactants such as SC105 and SC106 (manufactured by Asahi Glass Co., Ltd.), organosiloxane polymer KP3
No. 41 (manufactured by Shin-Etsu Chemical Co., Ltd.) and acrylic or methacrylic acid (co) polymer polyflow Nos. 75 and 75
95 (manufactured by Kyoeisha Yushi Kagaku Kogyo KK) and the like.

The amount of these surfactants is usually in the range of 100 parts by weight of the total amount of the alkali-soluble novolak resin and 1,2-quinonediazide compound in the above composition.
It is at most 2 parts by weight, preferably at most 1 part by weight. Also,
In the above composition, to visualize the latent image of the radiation-irradiated portion, or to reduce the effect of halation upon radiation, a coloring agent may be added, and an adhesion aid may be added to improve the adhesiveness. it can.

Further, a storage stabilizer, an antifoaming agent and the like can be added to the above-mentioned composition, if necessary. The above composition is prepared by dissolving a predetermined amount of the alkali-soluble novolak resin, the 1,2-quinonediazide compound and various compounding agents in a suitable solvent in a solvent, and filtering the resulting mixture with a filter having a pore size of about 0.2 μm, for example. This is applied to a silicon wafer or the like by spin coating, flow coating, roll coating or the like. Suitable solvents used in this case include glycol ethers such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether; cellosolve esters such as methyl cellosolve acetate and ethyl cellosolve acetate; methyl 2-oxypropionate; Examples thereof include monooxymonocarboxylic esters such as ethyl oxypropionate, ketones such as methyl ethyl ketone and cyclohexanone, and esters such as ethyl acetate and butyl acetate. These solvents are used alone or in combination of two or more. Also, if necessary, benzyl ethyl ether,
Ethers such as dihexyl ether, glycol ethers such as diethylene glycol monomethyl ether and diethylene glycol monoethyl ether, ketones such as acetonylacetone and isophorone, fatty acids such as caproic acid and caprylic acid, 1-octanol, 1-nonanol and benzyl High boiling solvents such as alcohols such as alcohol, benzyl acetate, ethyl benzoate, diethyl oxalate, diethyl maleate, diethyl maleate, γ-butyrolactone, ethylene carbonate, propylene carbonate, esters such as phenyl cellosolve acetate, toluene, xylene, etc. Aromatic hydrocarbons can be added.

Examples of the developer of the above composition include inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate and aqueous ammonia, and primary amines such as ethylamine and n-propylamine. Amines, diethylamine, secondary amines such as di-n-propylamine, tertiary amines such as triethylamine and methyldiethylamine, alcoholamines such as dimethylethanolamine and triethanolamine, tetramethylammonium hydroxide, Quaternary ammonium salts such as tetraethylammonium hydroxide, or pyrrole, piperidine, 1,8-diazabicyclo (5,4,0) -7-undecene, 1,5-diazabicyclo (4,3,0) -5-nonane Alkaline water obtained by dissolving cyclic amines such as Liquid is used.

An alkaline aqueous solution obtained by adding an appropriate amount of a water-soluble organic solvent, for example, an alcohol such as methanol or ethanol or a surfactant to the developer may be used as the developer.

[0026]

EXAMPLES The present invention will be described below in detail with reference to examples, but the present invention is not limited by these examples.

Example 1 (1) 162 g of m-cresol was placed in a 5 L three-neck separable flask equipped with a stirrer, a cooling tube and a thermometer.
(1.5 mol), 648 g (6 mol) of p-cresol,
770 g of a 37% by weight aqueous formaldehyde solution and 0.45 g of oxalic acid were charged, and the separable flask was immersed in an oil bath, and reacted for 1 hour while maintaining the internal temperature at 100 ° C. Thereafter, 270 g (2.5 mol) of m-cresol was continuously charged into the separable flask with the progress of the reaction and reacted for 2 hours.

Next, the temperature of the oil bath was raised to 170 ° C., and simultaneously the pressure in the separable flask was reduced to remove water, unreacted m-cresol, p-cresol, formaldehyde and oxalic acid. And recovered. The novolak resin was dissolved in tetrahydrofuran, and the molecular weight distribution of the novolak resin was measured by the GPC method described above. Table 1 shows the results.

(2) 100 parts by weight of the novolak resin thus obtained and 27 parts by weight of the 1,2-quinonediazide compound shown in Table 1 were dissolved in 360 parts by weight of ethyl cellosolve acetate to give a positive impression. A radiation resin composition solution was prepared. This composition solution was filtered through a membrane filter having a pore size of 0.2 μm. This solution was spin-coated on a silicon wafer with a spinner, and prebaked on a hot plate at 90 ° C. for 2 minutes to form a 1.2 μm thick resist layer. Next, exposure is performed by changing the exposure time while shifting the exposure area so as not to overlap with a GCA 4800DSW reduction projection exposure apparatus equipped with a test pattern reticle, and developed for 60 seconds using a 2.4% by weight aqueous solution of tetramethylammonium hydroxide. And rinsed with water and dried.

Using a scanning electron microscope with respect to the obtained resist pattern, the resist pattern after development was 1.
When an exposure time for forming a line and space pattern of 2 μm or more accurately (hereinafter referred to as an optimum exposure time) was obtained, the sensitivity was 0.40 seconds, which was good.
No scum-like development residue was observed. Further, when the minimum resist pattern size at the optimum exposure time (hereinafter, referred to as “resolution”) was obtained, it was 0.8 μm, which was a high resolution. When the temperature at which the pattern began to collapse was determined by placing the wafer on which the resist pattern was formed in an oven, the temperature was 150 ° C.
It was found that the resist had good heat resistance. Further, the adhesiveness between the resist and the substrate is good, and the etching solution does not penetrate between the resist and the substrate.
The resist pattern of No. m did not peel at all, and the wet etching property was good. Table 1 shows the results.

Examples 2 to 8 (1) Using m-cresol and p-cresol shown in Table 1, a novolak resin was synthesized in the same manner as in Example 1, and the molecular weight distribution of the novolak resin was measured by GPC. Was measured. Table 1 shows the results. (2) Then, a positive-type radiation-sensitive resin composition solution was prepared in the same manner as in Example 1 except that the 1,2-quinonediazide compound of the type and the addition amount shown in Table 1 was used. An evaluation was performed. Table 1 shows the results. All were excellent in sensitivity, resolution, developability, heat resistance and wet etching properties.

Comparative Example 1 (1) 108 g (1 mol) of m-cresol and 864 g of p-cresol were placed in the same separable flask as in Example 1.
(8 mol), 770 aqueous solution of 37% by weight formaldehyde
g and oxalic acid (0.45 g) were charged, and the separable flask was immersed in an oil bath and reacted for 1 hour while maintaining the internal temperature at 100 ° C. Next, 108 g (1 mol) of m-cresol was continuously charged into the separable flask with the progress of the reaction and allowed to react for 2 hours. Thereafter, the same treatment as in Example 1 was performed to determine the molecular weight distribution of the novolak resin by the GPC method. It was measured. Table 1 shows the results. (2) Then, a positive-type radiation-sensitive resin composition solution was prepared in the same manner as in Example 1 except that the 1,2-quinonediazide compound of the type and the addition amount shown in Table 1 was used. An evaluation was performed. The results are shown in Table 1. As a result, the sensitivity, developability, resolution, heat resistance, and wet etching properties were inferior to those of the examples.

Comparative Example 2 (1) 432 g (4 mol) of m-cresol and 648 g of p-cresol were placed in the same separable flask as in Example 1.
(6 moles), 37% by weight formaldehyde aqueous solution 770
g and oxalic acid (0.45 g) were charged all at once, and the separable flask was immersed in an oil bath.
Allowed to react for hours. Then, the same processing as in the first embodiment is performed to
The molecular weight distribution of the novolak resin was measured by the PC method. Table 1 shows the results. (2) Then, a positive-type radiation-sensitive resin composition solution was prepared in the same manner as in Example 1 except that the 1,2-quinonediazide compound of the type and the addition amount shown in Table 1 was used. An evaluation was performed. The results are shown in Table 1. As a result, the sensitivity, resolution, developability, heat resistance and wet etching properties were inferior to those of the examples.

Comparative Example 3 (1) Into the same separable flask as in Example 1, m-cresol 648 g (6 mol), p-cresol 432 g
(4 mol), 37% by weight formaldehyde aqueous solution 770
g and oxalic acid (0.45 g) were charged, and the separable flask was immersed in an oil bath and reacted for 1 hour while maintaining the internal temperature at 100 ° C. Thereafter, the same treatment as in Example 1 was performed, and the molecular weight distribution of the novolak resin was measured by the GPC method. Table 1 shows the results. (2) Then, a positive-type radiation-sensitive resin composition solution was prepared in the same manner as in Example 1 except that the 1,2-quinonediazide compound of the type and the addition amount shown in Table 1 was used. An evaluation was performed. The results are shown in Table 1. The sensitivity, resolution, developability,
Heat resistance and wet etching properties were poor.

Comparative Example 4 (1) Into the same separable flask as in Example 1, m-cresol 648 g (6 mol), p-cresol 432 g
(4 mol), 37% by weight formaldehyde aqueous solution 770
g and 9 g of oxalic acid, the separable flask was immersed in an oil bath, and reacted for 1 hour while maintaining the internal temperature at 100 ° C.
Thereafter, the same treatment as in Example 1 was performed, and the molecular weight distribution of the novolak resin was measured by the GPC method. Table 1 shows the results. (2) Then, a positive-type radiation-sensitive resin composition solution was prepared in the same manner as in Example 1 except that the 1,2-quinonediazide compound of the type and the addition amount shown in Table 1 was used. An evaluation was performed. The results are shown in Table 1. As a result, the sensitivity, resolution, developability, heat resistance and wet etching properties were inferior to those of the examples.

Comparative Example 5 (1) In a separable flask similar to that in Example 1, 432 g (4 mol) of m-cresol and 216 g of p-cresol were placed.
(2 mol), 37% by weight formaldehyde aqueous solution 770
g and oxalic acid (0.45 g) were charged, and the separable flask was immersed in an oil bath and reacted for 1 hour while maintaining the internal temperature at 100 ° C. Then, 432 g (4 mol) of m-cresol was continuously charged into the separable flask as the reaction progressed, reacted for 2 hours, and then treated in the same manner as in Example 1 to measure the molecular weight distribution of the novolak resin by the GPC method. did. Table 2 shows the results. (2) Next, a positive-type radiation-sensitive resin composition solution was prepared in the same manner as in Example 1 except that the 1,2-quinonediazide compound of the type and the addition amount shown in Table 2 was used. An evaluation was performed. The results are shown in Table 2. As compared with the examples, the sensitivity, developability, resolution and heat resistance were good, but about 10% of the 0.8 μm resist pattern.
Peeling and lifting from the substrate were observed in the number of patterns corresponding to the above, and the adhesion to the substrate, that is, the wet etching property was poor.

Reference Example 1 A resist layer was formed in the same manner as in Example 1. Next, Canon F equipped with a test pattern reticle
The resist performance was evaluated in the same manner as in Example 1 except that the PA-1550 reduction projection exposure apparatus was used. As a result, the optimum exposure time was as high as 0.30 seconds, and no scum-like development residue was observed. . The resolution is 0.7 μm,
Very high resolution was obtained.

Reference Example 2 A resist layer was formed in the same manner as in Example 1. Next, Canon F equipped with a test pattern reticle
Using a PA-1550 reduction projection exposure apparatus, the resist performance was evaluated in the same manner as in Example 1 except for developing with a 2.2% by weight aqueous solution of tetramethylammonium hydroxide. The optimum exposure time was 0.6 seconds. The sensitivity was high, and no scum-like residual development was observed. The resolution was 0.6 μm, and a very high resolution was obtained.

[0039]

[Table 1]

[0040]

[Table 2]

[0041]

By using the alkali-soluble novolak resin of the present invention, a resist pattern having a high sensitivity, good developability, a line width of 1 μm or less can be resolved, dry etching resistance and wet etching can be obtained. A positive radiation-sensitive resin composition having good heat resistance and heat resistance can be obtained. This positive-type radiation-sensitive resin composition is sensitive to radiation such as ultraviolet rays, far ultraviolet rays, X-rays, electron beams, molecular beams, γ-rays, synchrotron radiation, and proton beams, and is particularly suitable for producing highly integrated integrated circuits. It is suitable as a resist.

Continuation of front page (72) Inventor Yoshinori Yoshida 2-11-24 Tsukiji, Chuo-ku, Tokyo Inside JSR Co., Ltd.

Claims (2)

[Claims] (A) 30-70 mol% of m-cresol
And a condensation reaction of cresol substantially consisting of 70 to 30 mol% of p-cresol with a carbonyl compound, wherein the condensation reaction is carried out by a method of adding cresol as the reaction proceeds, and (B) Polystyrene-equivalent molecular weight of 630 determined by gel permeation chromatography using monodisperse polystyrene as a standard.
0-25000, 2500-6000 and 150-9
When the maximum heights in the respective ranges of 00 are a, b and c, respectively, a / b = 0.4 to 1.5 and c / b = 0.
An alkali-soluble novolak resin which is in each range of 5-2. 2. The alkali-soluble novolak resin according to claim 1, which is used for a positive radiation-sensitive resin composition.