JPH0768435B2 - Radiation-sensitive resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a radiation-sensitive resin composition, more specifically, ultraviolet rays, far ultraviolet rays, X-rays, electron beams, molecular beams, γ-rays, synchrotron radiation, protons. The present invention relates to a radiation sensitive resin composition suitable as a positive resist for producing a highly integrated circuit sensitive to radiation such as a beam.

[Conventional technology]

The positive type resist is often used in the manufacture of integrated circuits because a high resolution resist pattern can be obtained.

However, in recent years, the degree of integration of integrated circuits has increased, and there is a demand for a positive resist which has high sensitivity and is capable of forming a resist pattern with improved resolution.
That is, when a fine resist pattern is formed with a positive resist, exposure takes only a short time, and when the latent image formed by exposure is developed with a developer composed of an alkaline aqueous solution, the exposed part comes into contact with the wafer. It is necessary to quickly develop even the part (bottom of the pattern) where there is. In the case of the conventional positive type resist, the sensitivity is insufficient, and the distance between the resist patterns to be formed is 1 μm.
In the case of the following, there is a problem that the developability of the bottom portion of the resist pattern is poor and the resolution is lowered when the interval between the resist patterns to be formed is 1 μm or less.

[Problems to be solved by the invention]

An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a radiation-sensitive resin composition for high integration, which is excellent in sensitivity, resolution and developability, and also has good heat resistance.

[Means for solving problems]

The present invention provides a radiation-sensitive resin composition containing an alkali-soluble novolac resin and a 1,2-quinonediazide compound, wherein the alkali-soluble novolac resin contains 20 to 80 mol% of m-cresol and 5 to 5 of p-cresol. 60 mol% and at least one poly (polyphenol) selected from 2,3-dimethylphenol, 3,4-dimethylphenol, 3,5-dimethylphenol, 2,3,5-trimethylphenol and 3,4,5-trimethylphenol 5 alkylphenols
Obtained by condensation polymerization of phenols containing -60 mol% and aldehydes, and having a polystyrene-reduced weight average molecular weight of 6,300 to 25,000, obtained by gel permeation chromatography with monodisperse polystyrene as the standard. ,Five
When the maximum height values of peaks in the range of 00 to 6,000 and 150 to 900 are a, b and c, respectively, a / b =
A resin in the range of 0 to 1.5 and c / b = 0.4 to 2,
Further, the 1,2-quinonediazide compound is 1,2-naphthoquinonediazide-5 of tetrahydroxybenzophenone.
-It is a sulfonic acid ester.

The alkali-soluble novolac resin used in the present invention (hereinafter, simply referred to as “novolak resin”) is obtained by condensation polymerization of phenols including m-cresol, p-cresol and polyalkylphenol and aldehydes under an acid catalyst. .

In the present invention, it is necessary to use at least one kind of the polyalkylphenol, but such as 2,4-dimethylphenol, 2,6-dimethylphenol, 2,3,6-trimethylphenol, and 2,4,5-trimethylphenol. It can also be used in combination with a polyalkylphenol other than the above.

The proportion of m-cresol, p-cresol and polyalkylphenol used is 20-80 / 5-60 / 5-60 (mol%), preferably 30-70 / 10-50 / 10-50 (mol%). Is. When the amount of m-cresol is less than 20 mol%, the developability is deteriorated, and when it exceeds 80 mol%, the heat resistance and the resolution are deteriorated. If the amount of p-cresol is less than 5 mol%, the resolution is deteriorated, and if it exceeds 60 mol%, the heat resistance and the developability are deteriorated. Further, when the amount of polyalkylphenol is less than 5 mol%, heat resistance is deteriorated, and when it exceeds 60 mol%, developability and resolution are deteriorated.

Examples of aldehydes include formaldehyde,
Paraformaldehyde, acetaldehyde, propylaldehyde, benzaldehyde, phenylacetaldehyde, α-phenylpropylaldehyde, β-phenylpropylaldehyde, o-hydroxybenzaldehyde,
m-hydroxybenzaldehyde, p-hydroxybenzaldehyde, p-chlorobenzaldehyde, m-chlorobenzaldehyde, p-chlorobenzaldehyde, o
-Nitrobenzaldehyde, m-nitrobenzaldehyde, p-nitrobenzaldehyde, o-methylbenzaldehyde, p-methylbenzaldehyde, p-ethylbenzaldehyde, pn-butylbenzaldehyde and the like, and among these compounds, formaldehyde,
Acetaldehyde is preferred. These aldehydes can be used alone or in admixture of two or more.

Aldehydes are usually 0.7 per mole of phenols.
It is used in a proportion of -3 mol, preferably 0.7-2 mol.

Further, the novolak resin, Toyo Soda Co. GPC column (G2000H ₆ 2 present, G3000H _6, G4000H ₆₎ was used, the flow rate 1.
5 ml / min, elution solvent tetrahydrofuran, column temperature 40
The polystyrene-reduced weight average molecular weight determined by the gel permeation chromatograph (GPC) method using monodisperse polystyrene as standard under the analysis condition of ℃ was 6,300 to 25,000, 2,5
When the maximum height values of peaks in the range of 00 to 6,000 and 150 to 900 are a, b and c, respectively, a / b = 0 to
It is a resin in the range of 1.5 and c / b = 0.4 to 2, preferably a / b = 0.2 to 1.3 and a / b = 0.5 to 1.5. The value of c / b is 1.
When it exceeds 5, the heat resistance is improved but the developability is deteriorated.
When the value of c / b exceeds 2, the resolution is improved but the heat resistance is deteriorated. When the value is less than 0.4, the heat resistance is improved but the resolution is decreased.

As the acid catalyst used for condensation polymerization, inorganic acids such as hydrochloric acid, nitric acid and sulfuric acid, and organic acids such as formic acid, oxalic acid and acetic acid can be used.

The amount of the acid catalyst used is preferably 1 × 10 ^{−5 to} 5 × 10 ⁻¹ mol with respect to 1 mol of the phenol.

In polycondensation, water is usually used as a reaction catalyst, but when the phenols used in polycondensation do not dissolve in an aqueous solution of aldehydes and become a heterogeneous system from the initial stage of the reaction, hydrophilicity is used as the reaction medium. It is also possible to use a solvent. Examples of these hydrophilic solvents include methanol and
Examples thereof include alcohols such as ethanol, propanol and butanol, and cyclic ethers such as tetrahydrofuran and dioxane. The amount of these reaction media used is
Usually, it is 20 to 1000 parts by weight per 100 parts by weight of the reaction raw material.

The reaction temperature can be appropriately adjusted depending on the reactivity of the reaction raw materials, but is usually 10 to 200 ° C, preferably 70 to 130 ° C.
Is.

As the polymerization method for obtaining the novolac resin, a polymerization method in which phenols, aldehydes, an acid catalyst and the like are charged all at once, and a polymerization method in which phenols are added as the reaction progresses are used. In the case of the method of adding phenols with the progress of the reaction, in order to produce the novolak resin more reproducibly and stably, first, a part of the phenols, the aldehydes and the acid catalyst are charged and polymerized, and then the remaining It is preferable to employ a method of adding phenols and polymerizing. After completion of the reaction, in order to remove the unreacted raw materials, the acid catalyst and the reaction medium present in the system, the temperature is generally raised to 130 to 230 ° C., the volatile matter is distilled off under reduced pressure, and then, Collect the novolac resin.

The 1,2-quinonediazide compound used in the present invention is a tetrahydroxybenzophenone represented by the following general formula (I). 1,2-naphthoquinonediazide-5-sulfonic acid ester of 2,3,4,5-tetrahydroxybenzophenone, 2,3,4,6-tetrahydroxybenzophenone, 2,3,5, 6-tetrahydroxybenzophenone,
2,3,4,2'-tetrahydroxybenzophenone, 2,3,5,
2'-tetrahydroxybenzophenone, 2,3,6,2'-tetrahydroxybenzophenone, 2,4,5,2'-tetrahydroxybenzophenone, 2,4,6,2'-tetrahydroxybenzophenone, 3,4, 5,2'-tetrahydroxybenzophenone, 2,3,4,3'-tetrahydroxybenzophenone, 2,3,5,3'-tetrahydroxybenzophenone,
2,3,6,3'-tetrahydroxybenzophenone, 2,4,5,
3'-tetrahydroxybenzophenone, 2,4,6,3'-tetrahydroxybenzophenone, 3,4,5,3'-tetrahydroxybenzophenone, 2,3,4,4'-tetrahydroxybenzophenone, 2,3, 5,4'-tetrahydroxybenzophenone, 2,3,6,4'-tetrahydroxybenzophenone, 2,4,5,4'-tetrahydroxybezophenone, 2,
4,6,4'-tetrahydroxybenzophenone, 3,4,5,4 '
-Tetrahydroxybenzophenone, 2,3,2 ', 3'-tetrahydroxybenzophenone, 2,3,2', 4'-tetrahydroxybenzophenone, 2,3,2 ', 5'-tetrahydroxybenzophenone, 2,3 , 2 ', 6'-Tetrahydroxybenzophenone, 2,3,3', 4'-Tetrahydroxybenzophenone, 2,3,3 ', 5'-Tetrahydroxybenzophenone, 2,4,2', 4'-Tetra Hydroxybenzophenone, 2,4,2 ', 5'-tetrahydroxybenzophenone, 2,4,2', 6'-tetrahydroxybenzophenone,
2,4,3 ', 4'-tetrahydroxybenzophenone, 2,4,
3 ', 5'-tetrahydroxybenzophenone, 2,5,2',
5'-tetrahydroxybenzophenone, 2,5,2 ', 6'-
Tetrahydroxybenzophenone, 2,5,3 ', 4'-tetrahydroxybenzophenone 2,5,3', 5'-tetrahydroxybenzophenone, 2,6,2 ', 6'-tetrahydroxybenzophenone, 2,6,3 ′, 4′-Tetrahydroxybenzophenone, 2,6,3 ′, 5′-Tetrahydroxybenzophenone, 3,4,3 ′, 4′-Tetrahydroxybenzophenone, 3,4,3 ′, 5′-Tetrahydroxybenzophenone , 2,5,3 ', 5'-tetrahydroxybenzophenone and other 1,2-naphthoquinonediazide-5-sulfonates.

Of these, 2,4,2 ', 4'-tetrahydroxybenzophenone-1,2-naphthoquinonediazide-5-sulfonic acid ester, 2,3,4,4'-tetrahydroxybenzophenone-1,2-naphthoquinonediazide- Compounds of 5-sulfonic acid esters are preferred. These 1,2-quinonediazide compounds may be used alone or in admixture of two or more.

The 1,2-naphthoquinonediazide-5-sulfonic acid ester of tetrahydroxybenzophenone includes tetrahydroxybenzophenone and 1,2-naphthoquinonediazide-
Obtained by condensing 5-sulfonic acid chloride in the presence of an amine, 1,2-naphthoquinonediazide-5-condensed with 1 mol of tetrahydroxybenzophenone
The molar ratio of sulfonic acid chloride (condensation ratio) is usually
It is 1 to 4, preferably 1.5 to 3.7. When the condensation ratio of tetrahydroxybenzophenone-1,2-naphthoquinonediazide-5-sulfonic acid ester is less than 1, the insolubilizing effect on the novolak resin is insufficient, and therefore tetrahydroxybenzophenone-1,2-naphthoquinonediazide-
It is necessary to extremely increase the amount of 5-sulfonic acid ester compounded, and the resist having such a composition has an extremely low heat resistance, which is not preferable.

The content of the 1,2-quinonediazide compound is preferably 5 to 100 parts by weight, and particularly preferably 10 to 50 parts by weight, based on 100 parts by weight of the novolac resin. If the compounding amount of the 1,2-quinonediazide compound is too small, the effect of insolubilizing the novolak resin is insufficient, and it is not possible to make a difference in the solubility of the exposed portion and the unexposed portion in the developer containing the alkaline aqueous solution, and thus patterning However, if the amount is too large, the amount of
All of the 2-quinonediazide compound cannot be decomposed, and development with a developer may be difficult.

The composition of the present invention may contain a sensitizer in order to improve the sensitivity as a resist. Examples of these sensitizers include 2H-pyrido [3,2-b] -1,4-oxazin-3 [4H] ones, 10H-pyrido [3,2-b] [1,
4] -Benzothiazines, laurazoles, hydantoins, barbituric acids, glycine anhydrides, 1-hydroxybenzotriazoles, alloxans, maleimides and the like. The compounding amount of these sensitizers is 1,2-
The amount is usually 100 parts by weight or less, preferably 4 to 60 parts by weight, based on 100 parts by weight of the quinonediazide compound.

Further, the composition of the present invention may contain a surfactant in order to improve the coating property, for example, the development property of the irradiation portion after striation or dry film formation. Examples of the surfactant include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether and other polyoxyethylene alkyl ethers, polyoxyethylene octylphenol ether, polyoxyethylene nonylphenol ether and other polyoxyethylene alkylphenols. Nonionic surfactants such as ethers, polyethylene glycol dilaurate, polyethylene glycol dialkyl esters such as polyethylene glycol distearate, Ftop EF301, EF303, EF352 (manufactured by Shin-Akita Kasei Co., Ltd.), Megafac F171, F172, F173 ( Dai Nippon Ink Co., Ltd., Florard FC430, FC431 (Sumitomo 3M), Asahi Guard AG710, Surflon S-382, SC10
1, SC102, SC103, SC104, SC105, SC106 (Made by Asahi Glass Co., Ltd.)
Fluorosurfactants such as, organosiloxane polymer
KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.), acrylic acid-based or methacrylic acid-based (co) polymer Polyflow No. 75, No. 95 (manufactured by Kyoeisha Yushi-Kagaku Kogyo Co., Ltd.) and the like can be mentioned. The content of these surfactants is usually 2% by weight or less, preferably 1% by weight or less, based on the solid content of the composition.

Further, in the composition of the present invention, a dye or pigment for visualizing a latent image of a radiation irradiated portion and reducing the effect of halation during radiation irradiation, and an adhesion aid for improving adhesiveness should be blended. You can also

Furthermore, in the positive-type radiation-sensitive resin composition of the present invention,
If necessary, a storage stabilizer, a defoaming agent, etc. may be added.

The composition of the present invention is prepared by dissolving a predetermined amount of the novolak resin, the 1,2-quinonediazide compound, and various compounding agents in a solvent so that the solid content concentration becomes 5 to 50% by weight, for example, a pore diameter of 0.2 μm. It is obtained by filtering with a medium filter. Examples of the solvent used in this case include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, and other ethylene glycol monoalkyl ethers, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether. Ether, diethylene glycol dialkyl ethers such as diethylene glycol dibutyl ether, ethylene glycol monoalkyl ether acetates such as methyl cellosolve acetate and ethyl cellosolve acetate, propylene glycol methyl ether acetate,
Propylene glycol monoalkyl ether acetates such as propylene glycol ethyl ether acetate and propylene glycol propyl ether acetate,
Aromatic hydrocarbons such as toluene and xylene, methyl ethyl ketone, ketones such as cyclohexanone, methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, oxyacetic acid Ethyl, methyl 2-hydroxy-3-methylbutanoate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-methyl-3-methoxybutyl propionate, 3-methyl-3-methoxybutyl butyrate Esters such as ethyl acetate, butyl acetate, methyl acetoacetate, and ethyl acetoacetate can be used. Two or more kinds of these solvents may be mixed and used. Further, ethers such as benzyl ethyl ether and dihexyl ether, diethylene glycol monoalkyl 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- Alcohols such as octanol, 1-nonanol and benzyl alcohol, high boiling point solvents such as benzyl acetate, ethyl benzoate, diethyl oxalate, diethyl maleate, γ-butyrolactone, ethylene carbonate, propylene carbonate and esters such as phenyl cellosolve acetate. Can also be added.

When applying the composition of the present invention to a substrate, hexamethyldisilazane, chloromethylsilane, or the like is previously applied to the substrate to be coated in order to improve the adhesion between the coating film and the substrate such as the silicon oxide film. be able to.

The developer of the composition of the present invention includes, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, inorganic alkalis such as aqueous ammonia, ethylamine, primary n-propylamine and the like. Secondary amines such as primary amines, diethylamine and di-n-propylamine, tertiary amines such as triethylamine and methyldiethylamine, dimethylethanolamine,
Alcohol amines such as triethanolamine, quaternary ammonium salts such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, choline or pyrrole, piperidine, 1,8-diazabicyclo (5,4,0) -7-undecene, 1,5-diazabicyclo (4,
An alkaline aqueous solution prepared by dissolving a cyclic amine such as 3,0) -5-nonane is used.

Further, an appropriate amount of an aqueous organic solvent, for example, alcohols such as methanol and ethanol and a surfactant may be added to the developer and used.

〔Example〕

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

The polystyrene reduced weight average molecular weight in the examples was measured by gel permeation chromatography (GPC) method. Further, the performance of the resist (sensitivity, resolution, developability, heat resistance) was evaluated by the following methods.

Sensitivity: In GCA 4800DSW reduction projection exposure machine, the exposure time is changed to perform exposure, then development is performed using a tetramethylammonium hydroxide 2.4 wt% aqueous solution at 25 ° C. for 60 seconds, rinsed with water and dried, An exposure time for forming a line-and-space pattern having a developed resist pattern of 1.2 μm in a one-to-one relationship with the obtained resist pattern using a scanning electron microscope (hereinafter, referred to as “optimum exposure time”). Called).

Development degree: The minimum resist pattern dimension at the optimum exposure time was measured.

Developability: The extent of scum and development residual was examined.

Heat resistance: The wafer was put in a clean oven, and the temperature at which the pattern began to break was measured.

Example 1 In a separable flask equipped with a stirrer, a cooling tube and a thermometer, 108 g (1.0 mol) of m-cresol and 324 g (3.0 mol) of p-cresol 195 g (1.
6 mol), 438 g of 37% by weight aqueous formaldehyde solution and 0.64 g of oxalic acid were placed, the separable flask was immersed in an oil bath, and the reaction was carried out for 0.5 hours while maintaining the internal temperature at 100 ° C., after which 432 g of m-cresol (4.0 mol) was added. ), And 49 g (0.4 mol) of 3.5-dimethylphenol were continuously charged into a separable flask as the reaction proceeded, and reacted for 0.5 hours.

Next, the oil bath temperature was raised to 180 ° C., and at the same time, the pressure in the separable flask was reduced to remove water, unreacted formaldehyde, m-cresol, p-cresol, 3,5-dimethylphenol and oxalic acid. Then, the molten novolac resin was returned to room temperature and recovered.

This novolak resin was dissolved in tetrahydrofuran, and the molecular weight distribution of the novolak resin was measured by the GPC method.
The results are shown in Table 1.

100 parts by weight of the novolak resin thus obtained and the 1,2-naphthoquinonediazide compound (I) 3 shown in Table 1
0 parts by weight was dissolved in 300 parts by weight of ethyl cellosolve acetate to prepare a composition solution. This composition solution has a pore size
Foreign particles were removed by filtration with a 0.2 μm filter.

This was spin-coated on a silicon wafer by a spinner by a conventional method, and then prebaked at 90 ° C. for 2 minutes on a hot plate to form a resist film having a dry film thickness of 1.2 μm.

Next, the exposure amount was changed with a reduction projection exposure machine (4800DSW manufactured by GCA), and tetramethylammonium hydroxide 2.
It was developed with a 4% by weight aqueous solution at 25 ° C. for 60 seconds, rinsed with water and dried. Observation of the obtained resist pattern with a scanning electron microscope revealed that no development residue was observed, the developability was good, the sensitivity was good, and a resist pattern having a line width of 0.8 μm could be resolved. When the temperature at which the pattern began to collapse when the wafer on which the resist pattern was formed was placed in an oven, it was 155 ° C., and it was found that the resist had good heat resistance. The results are shown in Table 1.

Example 2 The same separable frass as in Example 1 was mixed with m-cresol.
86 g (0.8 mol), p-cresol 324 g (3.0 mol), 3,5
-Prepare 293 g (2.4 mol) of dimethylphenol, 317 g of 37% by weight aqueous formaldehyde solution and 0.59 g of oxalic acid, immerse the separable flask in an oil bath, and carry out the reaction for 0.5 hours while maintaining the internal temperature at 100 ° C. Cresol 346g (3.2mol), 3,5-dimethylphenol 73g
(0.6 mol) was continuously charged into a separable flask as the reaction proceeded, and the reaction was carried out for 0.5 hours.

Thereafter, the same operation as in Example 1 was performed to recover the novolak resin, and its molecular weight distribution was measured. The results are shown in Table 1. Further, a composition solution was prepared in the same manner as in Example 1, filtered, and the resist performance was evaluated. The results are shown in Table 1.

Example 3 A separable flask similar to that used in Example 1 was charged with m-cresol.
65 g (0.6 mol), p-cresol 324 g (3.0 mol) 3,5-
Dimethylphenol 390 g (3.2 mol), 37% by weight formaldehyde dihydrate 319 g and oxalic acid 0.59 g were charged, the separable flask was immersed in an oil bath, and the reaction was carried out for 0.5 hours while keeping the internal temperature at 100 ° C., and then m-cresol. 259
g (2.4 mol) and 3,5-dimethylphenol 98 g (0.8
Mol) was continuously charged into a separable flask as the reaction proceeded, and the reaction was carried out for 0.5 hours. Thereafter, the same operation as in Example 1 was performed to recover the novolak resin, and its molecular weight distribution was measured. The results are shown in Table 1. Further, a composition solution was prepared in the same manner as in Example 1, filtered, and the resist performance was evaluated. The results are shown in Table 1.

Examples 4 to 7 Novolak resins were synthesized in the same manner as in Example 1 except that various phenols shown in Table 1 were used, and the molecular weight distribution of the novolac resins was measured. The results are shown in Table 1.

Further, a composition solution was prepared in the same manner as in Example 1, filtered, and the resist performance was evaluated. The results are shown in Table 1.

Example 8 The novolak resin obtained in Example 1 and the 1,2-naphthoquinonediazide compound (I of the type and addition amount shown in Table 2)
Using I), a composition solution of the present invention was prepared in the same manner as in Example 1, filtered, and the resist performance was evaluated. The results are shown in Table 2.

Example 9 The novolak resin obtained in Example 4 and the 1,2-naphthoquinonediazide compound (I of the type and addition amount shown in Table 2)
Using I), a composition solution was prepared in the same manner as in Example 1, filtered, and the resist performance was evaluated. The results are shown in Table 2, which shows excellent sensitivity, resolution, developability and heat resistance.

Example 10 The novolac resin obtained in Example 6 and the 1,2-naphthoquinonediazide compound (I of the kind and addition amount shown in Table 2)
Using I), a composition solution was prepared in the same manner as in Example 1, filtered, and the resist performance was evaluated. The results are shown in Table 2.

Example 11 The novolac resin obtained in Example 1 and the 1,2-naphthoquinonediazide compound (I
Using II), a composition solution was prepared in the same manner as in Example 1, filtered, and the resist performance was evaluated. The results are shown in Table 2.

Example 12 The novolak resin obtained in Example 7 and the 1,2-naphthoquinonediazide compound (I
Using I), a composition solution was prepared in the same manner as in Example 1, filtered, and the resist performance was evaluated. The results are shown in Table 2.

Comparative Example 1 A separable flask similar to that used in Example 1 was charged with m-cresol.
162g (1.5mol), p-cresol 54g (0.5mol), 3,5
-Dimethylphenol 976 g (8.0 mol), 37 wt% formaldehyde aqueous solution 438 g and oxalic acid 0.80 g were charged, the separable flask was immersed in an oil bath, and the reaction was carried out for 2 hours while keeping the internal temperature at 100 ° C. Thereafter, the novolak resin was recovered in the same manner as in Example 1, and the molecular weight distribution of the novolac resin was measured. The results are shown in Table 3. Further, a composition solution was prepared in the same manner as in Example 1, filtered, and the resist performance was evaluated. The results are shown in Table 3.

Comparative Example 2 In a separable flask similar to that used in Example 1, 864 g (8.0 mol) of m-cresol and 244 g of 2,5-dimethylphenol (2.
0 mol), 438 g of 37% by weight aqueous formaldehyde solution and 0.80 g of oxalic acid were charged, the separable flask was immersed in an oil bath, and the reaction was carried out for 2 hours while maintaining the internal temperature at 100 ° C.
Thereafter, the novolak resin was recovered in the same manner as in Example 1, and the molecular weight distribution of the novolac resin was measured. The results are shown in Table 3. Further, a composition solution was prepared in the same manner as in Example 1, filtered, and the resist performance was evaluated.
The results are shown in Table 3.

Comparative Example 3 In a separable flask similar to that used in Example 1, 108 g (1.0 mol) of m-cresol, 162 g (1.5 mol) of p-cresol,
195 g (1.6 mol) of 3,5-dimethylphenol, 438 g of 37% by weight aqueous formaldehyde solution and 0.64 g of oxalic acid were charged, the separable flask was immersed in an oil bath, and the reaction was carried out for 0.5 hours while maintaining the internal temperature at 100 ° C. Further, m-cresol 432 g (4.0 mol), p-cresol 162 g (1.5 mol) and 3,5-dimethylphenol 49 g (0.4 mol) were continuously charged into a separable flask as the reaction proceeded,
The reaction was carried out for 0.5 hours. After that, in the same manner as in Example 1,
The novolak resin was recovered and the molecular weight distribution of the novolak resin was measured. The results are shown in Table 3. Further Example 1
A composition solution was prepared in the same manner as above, filtered, and the resist performance was evaluated. The results are shown in Table 3.

Comparative Example 4 In a separable flask similar to that used in Example 1, 216 g (2.0 mol) of m-cresol, 324 g (3.0 mol) of p-cresol,
195 g (1.6 mol) of 3,5-dimethylphenol, 438 g of 37% by weight aqueous formaldehyde solution and 0.64 g of oxalic acid were charged, the separable flask was immersed in an oil bath, and the reaction was carried out for 0.5 hours while maintaining the internal temperature at 100 ° C., and then further. 324 g (3.0 mol) of m-cresol, 49 g of 3,5-dimethylphenol
(0.4 mol) was continuously charged into a separable flask as the reaction proceeded, and reacted for 0.5 hours. Thereafter, the novolak resin was recovered in the same manner as in Example 1, and the molecular weight distribution of the novolac resin was measured. The results are shown in Table 3. Further, a composition solution was prepared in the same manner as in Example 1,
After filtering, the resist performance was evaluated. The results are shown in Table 3.

[Advantages of the Invention] According to the radiation-sensitive resin composition of the present invention, it is possible to obtain a positive resist having excellent resolution, sensitivity, developability and heat resistance, and also excellent dry etching resistance.

Claims (1)

[Claims] 1. A radiation-sensitive resin composition containing an alkali-soluble novolac resin and a 1,2-quinonediazide compound, wherein the alkali-soluble novolac resin is m-
Cresol 20 to 80 mol%, p-cresol 5 to 60 mol% and 2,3-dimethylphenol, 3,4-dimethylphenol, 3,5-dimethylphenol, 2,3,5-trimethylphenol and 3, Gel permeation obtained by condensation polymerization of phenols containing 5 to 60 mol% of at least one polyalkylphenol selected from 4,5-trimethylphenol and aldehydes, and using monodisperse polystyrene as standard. The polystyrene-reduced weight average molecular weight determined by the chromatographic method is 6,300 to 25,00.
When the maximum height values of the peaks in the range of 0, 2,500 to 6,000 and 150 to 900 are a, b and c, respectively,
A resin in the range of a / b = 0 to 1.5 and c / b = 0.4 to 2, and the 1,2-quinonediazide compound is a 1,2-naphthoquinonediazide-5-sulfonic acid ester of tetrahydroxybenzophenone. A radiation-sensitive resin composition characterized by being present.