JPH11255855A - Alkali-soluble novolak resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an alkali-soluble novolak resin suitably used as a positive resist for a high integrated circuit excellent in resolution, sensitivity, developing performance and heat resistance. SOLUTION: The titled novolak resin is obtained by the condensation reaction of phenols comprising 30-90 mole % of m-cresol and 70-10 mol.% of a compound represented by the formula (except m-cresol), [wherein X stands for -CH3 , -C2 H5 , -C(CH3 )3 , -CO2 CH3 or -CH2 C2 H5 ; 3>=n>=1; and 3>=m>=1] with formaldehyde, the condensation reaction being carried out by adding the components according to the progress of the reaction and the mol.wt. of the resin being such that a/b=0-1.5 and c/b=0.5-1.5, where a, b and c is the height of the highest peak in the range of mol.wt., in terms of polystyrene measured by the GPC (gel permeation chromatography), of 6,300 to 25,000, 2,500 to 6,000 and 150 to 900, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an alkali-soluble novolak resin. More specifically, in the presence of a 1,2-quinonediazide compound, a resist for producing an integrated circuit, particularly in response to radiation such as ultraviolet ray, far ultraviolet ray, X-ray, electron beam, molecular beam, γ-ray, synchrotron radiation and proton beam. The present invention relates to an alkali-soluble novolak resin suitably used for preparing a positive-type radiation-sensitive resin composition suitable as a resin.

[0002]

2. Description of the Related Art Conventionally, as a resist used for fabricating an integrated circuit, a negative resist in which a bisazide compound is blended with a cyclized rubber, and a resist which is 1 in an alkali-soluble resin.
A positive resist containing a 2-quinonediazide compound is known. In a negative resist, the bisazide compound desorbs nitrogen by irradiation with ultraviolet light to form nitrene, and cross-links the cyclized rubber three-dimensionally. There is a difference in the pattern, which results in patterning, but the crosslinking does not mean that the UV-irradiated portion is completely cured, so the swelling of the resist pattern in the developer is large,
There is a disadvantage that the resolution of the resist pattern is poor.

On the other hand, since a positive resist contains an alkali-insoluble 1,2-quinonediazide compound in an alkali-soluble resin, it hardly dissolves in a developing solution composed of an alkaline aqueous solution and hardly swells. That is, in the positive resist, the 1,2-quinonediazide compound in the UV-irradiated portion changes to indene carboxylic acid, and even when the resist is developed with a developing solution composed of an alkaline aqueous solution, the change in the unirradiated portion serving as the resist pattern is extremely small. Thus, a resist pattern with high resolution that is faithful to the pattern of the mask can be obtained. For this reason, in recent years, where a higher degree of integration of integrated circuits is required, a positive resist having an excellent resolution is often used.

[0004] However, even in the case of a positive resist, it is difficult to obtain a resist pattern faithful to a mask unless the ultraviolet-exposed portion is in contact with the wafer unless the resist is rapidly developed. At present, when the resist pattern interval (hereinafter, referred to as “line width”) is as narrow as 1 μm or less, the developability of the bottom portion of the resist pattern greatly affects the resolution. In the formation of an integrated circuit, the reduction projection exposure method employed to reduce the resolution to 1 μm or less has a problem that the throughput is low, that is, the exposure time per wafer is long. In order to solve such a problem, it is necessary to increase the sensitivity of the resist.

On the other hand, as the degree of integration of LSI has been improved, the width of wiring has been reduced, and dry etching has been used as a means for this. It is desirable that the resist pattern does not change by heating during the dry etching, but the heat resistance of the conventional positive resist is insufficient.
Thus, the performance required as a resist is
There are “resolution”, “sensitivity”, “developability”, and “heat resistance”, among which sensitivity and heat resistance tend to be contradictory. That is, when the molecular weight of the novolak resin is reduced,
Although the sensitivity increases, the heat resistance deteriorates. Also, when the molecular weight of the novolak resin is reduced, the developability and the resolution tend to be good, but the heat resistance deteriorates. As described above, if one of the performances required for the above-mentioned resist is to be improved, the other deteriorates. Therefore, all of the conventional positive resists are insufficient.

[0006]

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 radiation-sensitive resin composition. Another object of the present invention is to solve the problems of the prior art and prepare a positive radiation-sensitive resin composition suitable as a positive resist for high integration with excellent resolution, sensitivity, developability and heat resistance. To provide an alkali-soluble novolak resin which is suitably used for the above-mentioned process. Still other objects and advantages of the present invention will become apparent from the following description.

[0007]

According to the present invention, m-cresol of 30 to 90 mol% and a compound of the formula (I)

Embedded image Wherein, X is _{-CH 3, -C 2 H 5,} -C (C
H _{3) 3,} means -CO ₂ CH ₃ or -CO ₂ C ₂ H _5, except 3 ≧ n ≧ 1,3 ≧ m ≧ 1 and is] in compounds represented (but m- cresol) 70 Obtained by subjecting a phenol containing 10 to 10 mol% to a condensation reaction with formaldehyde, the condensation reaction being carried out by a method of adding the phenol with the progress of the reaction, and gel permeation using monodisperse polystyrene as a standard. Chromatograph (GP
The polystyrene equivalent molecular weight determined by the method C) is 6,30.
0-25,000, 2,500-6,000 and 15
When the maximum height values of the peaks in the range of 0 to 900 are a, b and c, respectively, a / b = 0 to 1.5 and c / b = 0.5 to 1.5. The present invention relates to an alkali-soluble novolak resin.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The alkali-soluble novolak resin of the present invention is obtained by condensing formaldehyde with a phenol containing 30 to 90 mol% of m-cresol and 30 to 90 mol% of the compound of the formula (I). Can be

The compounds of the general formula (I) used in the present invention include, for example, o-cresol, 3,5-dimethylphenol, 2,5-dimethylphenol, 2,3-dimethylphenol
Dimethylphenol, 2,4-dimethylphenol,
2,6-dimethylphenol, 3,4-dimethylphenol, 2,3,5-trimethylphenol, 4-t-butylphenol, 2-t-butylphenol, 3-t-
Butylphenol, 2-methylresorcinol, 4-methylresorcinol, 5-methylresorcinol, 4-
t-butylcatechol, 4-methoxyphenol, 3-
Methoxyphenol, 2-methoxyphenol, 2-methoxycatechol, 2-methoxyresorcinol, 3-
Methoxyresorcinol, 2,3-dimethoxyphenol, 2,5-dimethoxyphenol, 3,5-dimethoxyphenol, methyl gallate, ethyl gallate,
Methyl methoxy-4,5-dihydroxybenzoate, 3-
Ethyl methoxy-4,5-dihydroxybenzoate, 4-
Methyl methoxy-3,5-dihydroxybenzoate, 4-
Ethyl methoxy-3,5-dihydroxybenzoate, 3,
Methyl 4-dimethoxy-5-hydroxybenzoate, 3,
Ethyl 4-dimethoxy-5-hydroxybenzoate, 3,
Methyl 5-dimethoxy-4-hydroxybenzoate, 3,
Ethyl 5-dimethoxy-4-hydroxybenzoate, 3-
Ethylphenol, 2-ethylphenol, 4-ethylphenol, 2,3,5-triethylphenol, 3,
5-diethylphenol, 2,5-diethylphenol, 2,3-diethylphenol and the like can be mentioned. These compounds are used alone or in combination of two or more.

In the present invention, the ratio of m-cresol to the compound of the formula (I) (m-cresol / compound of the formula (I)) is from 30 to 90/70 by molar ratio.
10 to 10. The use ratio of m-cresol is 30 mol%
If it is less than 90% or more than 90 mol%, the resolution and developability will be reduced. In addition, this use ratio is the use ratio of the raw material at the time of synthesizing the novolak resin.

The alkali-soluble novolak resin in the present invention is a GPC column (G2000H manufactured by Toyo Soda).
₆ 2, G3000H ₆ 1 present, using G4000H ₆ 1 present), flow rate 1.5 ml / min, eluent tetrahydrofuran, analytical conditions of column temperature 40 ° C., gel permeation Activation chromatography to monodisperse polystyrene as the standard The values of the maximum heights of the peaks having a molecular weight in terms of polystyrene in the range of 6,300 to 25,000, 2,500 to 6,000, and 150 to 900 determined by the graph (GPC) method are a, b, and c, respectively. Where a / b = 0 to
It is a resin in the range of 1.5 and c / b = 0.5 to 1.5. By using this alkali-soluble novolak resin, a resin excellent in resolution, sensitivity, developability and heat resistance can be obtained as compared with a conventional alkali-soluble novolak resin.

When the value of a / b exceeds 1.5, developability and sensitivity deteriorate. If the value of c / b exceeds 1.5, the heat resistance deteriorates, and the value of c / b becomes 0.5.
If it is less than the above, the sensitivity and the resolution are reduced. In the present invention, the alkali-soluble novolak resin is synthesized by condensing the phenol with formaldehyde in the presence of an acid catalyst, but can also be synthesized without a catalyst. Examples of the acid catalyst used at this time 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 formaldehyde used is phenols 1
The amount of the acid catalyst is preferably from 0.7 to 3 mol per mol, and the amount of the acid catalyst is preferably from 0 to 0.1 mol per mol of the phenol.

In the condensation reaction, water is usually used as a reaction catalyst. However, when the phenol used does not dissolve in an aqueous formaldehyde solution and becomes heterogeneous from the beginning of the reaction, a hydrophilic solvent is used as a reaction medium. Can also be used. Examples of the hydrophilic solvent used at this time include alcohols such as methanol, ethanol, propanol and butanol, and cyclic ethers such as tetrahydrofuran and dioxane. The use amount of these reaction media is preferably 20 to 1,000 parts by weight per 100 parts by weight of the total amount of phenols and formaldehyde. The reaction temperature of the condensation reaction can be appropriately adjusted according to the reactivity between phenols and formaldehyde, but is usually 10 to 200 ° C, preferably 70 to 130 ° C.
It is.

As a method for obtaining the alkali-soluble novolak resin, a method is employed in which phenols are added to formaldehyde and an acid catalyst as the reaction proceeds to cause a reaction. In the method of adding and reacting the phenols with the progress of the reaction, in order to produce the alkali-soluble resin more reproducibly and stably, a part of the phenols, formaldehyde and an acid catalyst are first charged and polymerized. Then, it is preferable to adopt a method in which the remaining phenols are added as the reaction proceeds to cause a reaction. After the completion of the condensation reaction, the internal temperature is generally raised to 1 to remove unreacted substances, acid catalyst and reaction medium present in the system.
The temperature is increased to 30 to 230 ° C., and volatile components are distilled off under reduced pressure.
Next, the molten alkali-soluble novolak resin is dripped onto a steel belt or the like to recover the alkali-soluble novolak resin. Alternatively, a method in which the alkali-soluble novolak resin is recovered by dissolving it in a solvent may be used.

The alkali-soluble novolak resin of the present invention is mixed with a 1,2-quinonediazide compound to give a positive-type radiation-sensitive resin 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 (poly) hydroxybenzenes such as benzoquinonediazide-4-sulfonic acid ester, resorcinol-1,2-naphthoquinonediazide-4-sulfonic acid ester, pyrogallol-1,2-naphthoquinonediazide-5-sulfonic acid ester -Quinonediazide sulfonic 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-trihydroxyphenone-n-hexyl ketone-1,2-naphthoquinonediazide-4-sulfonic acid ester, 2 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-sulfone Acid ester, 2,2 ', 4,4'-tetrahydroxybenzophenone-1,2-naphthoquinonediazide-4-sulfonic acid ester, 2,3,4,4'-tetrahydroxybenzophenone-1,2-naphthoquinonediazide- 4-
Sulfonic acid ester, 2,2 ', 3,4,6'-pentahydroxybenzophenone-1,2-naphthoquinonediazide-4-sulfonic acid ester, 2,2', 3,4
6'-pentahydroxybenzophenone-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'-hexahydroxybenzophenone-1,2 -Naphthoquinonediazide-
5-sulfonic acid ester, 2,3 ', 4,4', 5'6
-Hexahydroxybenzophenone-1,2-naphthoquinonediazide-4-sulfonic acid ester, 2,3 ',
4,4 ', 5'6-hexahydroxybenzophenone-
1,2-naphthoquinonediazido-5-sulfonic acid ester and other (poly) hydroxyphenyl alkyl ketones or 1,2
-Quinonediazide sulfonic acid esters,

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 ( 1,2-quinonediazidesulfonic acid esters of bis [(poly) hydroxyphenyl] alkane such as 2,3,4-trihydroxyphenyl) propane-1,2-naphthoquinonediazide-5-sulfonic acid ester; Lauryl-1,2-naphthoquinonediazide-4-sulfonic acid ester of dihydroxybenzoate, 2 3,4-trihydroxybenzoic acid phenyl-1,2-naphthoquinonediazide-5-sulfonic acid ester, 3,4,5-trihydroxypropyl propyl-1,2-naphthoquinonediazide-5-sulfonic acid ester, 3, 1,2-quinonediazidesulfonic acid ester of (poly) hydroxybenzoic acid alkyl ester or (poly) hydroxybenzoic acid arylester such as phenyl-1,2-naphthoquinonediazide-5-sulfonic acid ester of 4,5-trihydroxybenzoic acid Kind,

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) benzene-
1,2-quinonediazidosulfonic acid esters of bis [(poly) hydroxybenzoyl] alkane or bis [(poly) hydroxybenzoyl] benzene, such as 1,2-naphthoquinonediazide-5-sulfonic acid ester;

Ethylene glycol di (3,5-dihydroxybenzoate) -1,2-naphthoquinonediazide-5-sulfonic acid ester, polyethylene glycol (3,4,5-trihydroxybenzoate) -1,2
1,2-quinonediazidosulfonic acid esters of (poly) ethylene glycol-di [(poly) hydroxybenzoate] such as naphthoquinonediazide-5-sulfonic acid ester, and α-pyrone-based natural dyes having a hydroxyl group of 1,
Examples thereof include 2-quinonediazidosulfonic acid esters, 1,2-quinonediazidosulfonic acid esters of hydroxyl group-containing natural γ-pyrone dyes, and 1,2-quinonediazidesulfonic acid esters of hydroxyl-containing diazine natural dyes. In addition to these compounds, Li.
ght-Sensitive Systems ”339-352, (1965), John W
“Photo by WS DeForest, iley & Sons (New York)
resist ”50, (1975), McGraw-Hill, Inc., (New York)
1,2-quinonediazide compounds described in the above can also be used.

These 1,2-quinonediazide compounds are used alone or as a mixture of two or more. The amount of the 1,2-quinonediazide compound is usually 5 to 100 parts by weight, preferably 10 to 50 parts by weight, based on 100 parts by weight of the alkali-soluble novolak resin. When the amount is less than 5 parts by weight, 1,2-
Since the quinonediazide compound absorbs radiation and generates a small amount of carboxylic acid, patterning is difficult. On the other hand, when the quinonediazide compound exceeds 100 parts by weight, all of the 1,2-quinonediazide compound added by short-time radiation is used. Cannot be decomposed, and it becomes difficult to develop with a developing solution composed of an alkaline aqueous solution.

These sensitizers can be added to the positive radiation-sensitive resin composition 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 and 10H-pyrido [3,2-b].
[1,4] -benzothiazines, urazoles, hydantoins, barbituric acids, glycine anhydrides, 1-
Hydroxybenzotriazoles, alloxanes, maleimides, and further described in JP-B-48-12242, JP-B-48-35402, JP-A-58-37641, JP-A-58-149042, and the like. Sensitizers. The compounding amount of the sensitizer is
To 100 parts by weight of the quinonediazide compound,
It is not more than 00 parts by weight, preferably 4 to 60 parts by weight.

A surfactant may be added to the positive-type radiation-sensitive resin composition in order to improve coatability, for example, developability of a radiation-irradiated portion after striation or formation of 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 dilaurate, polyethylene glycol dialkyl ethers such as polyethylene glycol distearate, etc., EFTOP EF301, EF
303, EF352 (manufactured by Shin-Akita Kasei Co., Ltd.), Megafac F171 and F173 (manufactured by Dainippon Ink and Chemicals, Inc.), and a fluoroalkyl group or perfluoroalkyl group exemplified in JP-A-57-178242. Having a linear fluorine-based surfactant, Florado FC430, FC43
1 (manufactured by Sumitomo 3M Limited), Asahi Guard AG71
0, Surflon S-382, SC101, SC102,
Fluorinated surfactants such as SC103, SC104, SC105, SC106 (manufactured by Asahi Glass Co., Ltd.), organosiloxane polymer KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.),
Acrylic or methacrylic acid (co) polymer polyflow No. 75, No. 95 (Kyoeisha Yushi Kagaku Kogyo Co., Ltd.)
Manufactured).

These surfactants may be used alone or as a mixture of two or more. The amount of the surfactant is usually per 100 parts by weight of the total amount of the alkali-soluble novolak resin and the 1,2-quinonediazide compound in the composition,
It is at most 2 parts by weight, preferably at most 1 part by weight. Also,
In the positive-type radiation-sensitive resin composition, a coloring agent is used to visualize the latent image in the irradiated area or to reduce the influence of halation during irradiation, and an adhesion aid is used to improve the adhesiveness. It can also be blended.

Examples of the coloring agent include methyl violet 2B (CI No. 42555), malachite green (CI No. 42000) and Victoria Blue B (CIN
o. 44045), neutral red (CI No. 50)
040), Solvent Yellow 2 (CI No. 1102)
0), Solvent Yellow 6 (CI No. 11390),
Solvent Yellow 14 (CI No. 12055), Solvent Yellow 15 (CI No. 18820), Solvent Yellow 16 (CI No. 12700), Solvent Yellow 21 (CI No. 18690), Solvent Yellow D-33 (CI No. 47000), Solvent Yellow 56 (CINo. 11021), Solvent Orange 1
(CI No. 11920), Solvent Orange 2 (CI
No. 12100), Solvent Orange 14 (CINo.
26020), Solvent Orange 40, Solvent Red 3 (CI No. 12010), Solvent Red 8
(CINo. 12715), Solvent Red 23 (CIN
o. 26100), Solvent Red 24 (CI No. 2)
6105), Solvent Red 25 (CI No. 2611)
0), Solvent Red 27 (CI No. 26125),
Solvent Red (CI No. 45170B), Disperse Red 9 (CI No. 60505), Oil Scarlet 308 (CI No. 21260), Solvent Brown (CI No. 12020), Disperse Yellow 1
(CINo. 10345), Disperse Yellow 3 (C
INo. 11855), Disperse Yellow 4 (CIN
o. 12770), Disperse Yellow 8 (CINo.
27090), Disperse Yellow 42 (CINo. 1)
0338), Disperse Orange 1 (CI No. 110)
80), Disperse Orange 3 (CI No. 1100)
5), Disperse Orange 5 (CINo. 1110)
0), Disperse Orange 11 (CINo. 6070)
0), Disper Thread 1 (CINo. 11110),
Oil-soluble dyes such as Disperse Red 4 (CI No. 60755), Disperse Red 11 (CI No. 62015), Disperse Red 15 (CI No. 60710), Disperse Red 58 (CI No. 11135);

Miketone Fast Yellow 7G, Miketone Fast Orange 5R (Mitsui Toatsu Dye Co., Ltd.)
Methine dyes such as holon (manufactured by Sando), Macrolex Yellow 6G (manufactured by Bayer), stilbene,
Fluorescent brighteners such as 4,4-diaminostilbene sulfonic acid derivatives, coumarin derivatives and pyrazoline derivatives;
And hydroxyazo dyes described in JP-A-9-142538. The mixing amount of these coloring agents is 100% in total of the alkali-soluble novolak resin and the 1,2-quinonediazide compound in the positive-type radiation-sensitive resin composition.
It is usually at most 6 parts by weight, preferably at most 4 parts by weight, per part by weight.

Examples of the adhesion aid include 3-aminopropyltriethoxysilane, vinyltrichlorosilane,
Silicon compounds such as-(3,4-epoxycyclohexylethyl) trimethoxysilane are used. The compounding amount of the adhesion assistant is usually 4 parts by weight or less per 100 parts by weight of the total amount of the alkali-soluble novolak resin and the 1,2-quinonediazide compound in the positive-type radiation-sensitive resin composition.
It is preferably at most 2 parts by weight. Further, a storage stabilizer, an antifoaming agent, and the like can be added to the positive-type radiation-sensitive resin composition, if necessary.

When the positive-type radiation-sensitive resin composition is applied to a substrate, the alkali-soluble novolak resin,
The 1,2-quinonediazide compound and various compounding agents were prepared, for example, by dissolving each in a predetermined amount in an appropriate solvent so that the concentration was 5 to 50% by weight, and then, for example, filtering through a filter having a pore size of about 0.2 μm. The composition solution is applied to a silicon wafer or the like by spin coating, flow coating, roll coating, or the like.

Examples of the solvent 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; monooxymonocarboxylic acid esters such as methyl 2-oxypropionate and ethyl 2-oxypropionate; aromatic hydrocarbons such as toluene and xylene; methyl ethyl ketone; 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, ethers such as benzyl ethyl ether and dihexyl ether, glycol ethers such as diethylene glycol monomethyl ether and diethylene glycol monoethyl ether, ketones such as acetonylacetone and isophorone, and fatty acids such as caproic acid and caprylic acid. , 1
Alcohols such as -octanol, 1-nonanol, and benzyl alcohol; or esters such as benzyl acetate, ethyl benzoate, diethyl oxalate, diethyl maleate, γ-butyrolactone, ethylene carbonate, propylene carbonate, and phenyl cellosolve acetate. High boiling solvents can also be added.

Examples of the developer for the positive-type radiation-sensitive resin composition include inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and aqueous ammonia, ethylamine, and n-propylamine. Primary amines, such as diethylamine, di-n-propylamine, etc .; tertiary amines, such as triethylamine and methyldiethylamine; alcohol amines, such as dimethylethanolamine and triethanolamine; Quaternary ammonium salts such as methylammonium hydroxide, tetraethylammonium hydroxide and choline, or pyrrole, piperidine, 1,8-diazapicyclo (5,4,0) -7-undecene, 1,5-diazapicyclo (4,3 , 0) -5
An alkaline aqueous solution obtained by dissolving a cyclic amine such as nonane is used. When manufacturing an integrated circuit in which the use of a developer containing a metal becomes a problem, it is preferable to use an alkaline aqueous solution of a quaternary ammonium salt or a cyclic amine. Further, an appropriate amount of a water-soluble organic solvent, for example, an alcohol such as methanol or ethanol or a surfactant may be added to the developer.

[0030]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited by these Examples. Example 1 In a 5-liter separable flask equipped with a stirrer, a condenser and a thermometer, 324 g (3 mol) of m-cresol, 244 g (2 mol) of 3,5-dimethylphenol, 770 g of a 37% by weight aqueous solution of formaldehyde and 0.8 g of oxalic acid was charged, the separable flask was immersed in an oil bath, and reacted for 1 hour while maintaining the internal temperature at 100 ° C., and then 324 g (3 mol) of m-cresol and 244 g of 3,5-dimethylphenol ( 2 mol) was continuously charged into a separable flask as the reaction proceeded, and reacted for 2 hours.

Next, the temperature of the oil bath was raised to 180 ° C., and simultaneously the pressure inside the separable flask was reduced to remove water, formaldehyde, unreacted m-cresol, 3,5-dimethylphenol and oxalic acid. Next, the melted novolak resin was returned to room temperature and collected. This novolak resin was dissolved in tetrahydrofuran, and
The molecular weight distribution of the novolak resin was measured by the method. Table 1 shows the results. 100 parts by weight of the novolak resin thus obtained and 29 parts by weight of the 1,2-quinonediazide compound shown in Table 1 were mixed with ethyl cellosolve acetate 3
The mixture was dissolved in 01 parts by weight to prepare a positive radiation-sensitive resin composition solution. The composition solution was filtered through a filter having a pore size of 0.2 μm to remove foreign particles.

This was spin-coated on a silicon wafer by a spinner by a conventional method, and prebaked on a hot plate at 90 ° C. for 2 minutes to form a 1.2 μm thick resist film. Next, the exposure amount was changed using a reduction projection exposure machine, developed with a 2.4% by weight aqueous solution of tetramethylammonium hydroxide at 25 ° C. for 60 seconds, rinsed with water, dried, and the obtained resist pattern was scanned. Observation with a scanning electron microscope revealed that there was no development residue, that the sensitivity was good, that the resist pattern was not thin, and that a resist pattern having a line width of 0.8 μm could be resolved. 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, and found to be 150 ° C., indicating that the resist had good heat resistance. Table 1 shows the results.

Example 2 In the same separable flask as in Example 1, 270 g (2.5 mol) of m-cresol, 305 g (2.5 mol) of 3,5-dimethylphenol, 770 g of a 37% by weight aqueous formaldehyde solution, and 0.8 g of acid was 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, 270 g (2.5 mol) of m-cresol and 305 g of 3,5-dimethylphenol were further added. (2.5 mol) was continuously charged into a separable flask as the reaction proceeded, and reacted for 2 hours.
Thereafter, a novolak resin was synthesized in the same manner as in Example 1,
The molecular weight distribution of the novolak resin was measured by the GPC method. Table 1 shows the results. Next, a positive-type radiation-sensitive resin composition solution was prepared in the same manner as in Example 1 except that the addition amount of the 1,2-quinonediazide compound shown in Table 1 was used, followed by filtration and evaluation of the resist performance. . Table 1 shows the results. All were excellent in sensitivity, resolution, developability and heat resistance.

Example 3 In the same separable flask as in Example 1, 324 g (3 mol) of m-cresol, 272 g (2 mol) of 2,3,5-trimethylphenol, 892 g of a 37% by weight aqueous solution of formaldehyde and oxalic acid 3 0.0 g, the separable flask was immersed in an oil bath and reacted for 3 hours while maintaining the internal temperature at 100 ° C., and then m-cresol 3 was added.
24 g (3 mol) and 272 g (2 mol) of 2,3,5-trimethylphenol were continuously charged into the separable flask as the reaction progressed, and reacted for 3 hours. Thereafter, 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 the GPC method. Table 1 shows the results. Next, a positive radiation-sensitive resin composition solution was prepared and filtered in the same manner as in Example 1 to evaluate the resist performance. Table 1 shows the results. All were excellent in sensitivity, resolution, developability and heat resistance.

Example 4 In a separable flask similar to that of Example 1, 216 g (2 mol) of m-cresol and 4-t-butylphenol 30 were added.
0 g (2 mol), 37% by weight aqueous formaldehyde solution 7
70 g and oxalic acid 3.0 g were charged, and the separable flask was immersed in an oil bath.
Let react for hours, then 648 g of m-cresol
(6 mol) was continuously charged into a separable flask as the reaction proceeded, and reacted for 4 hours. Thereafter, 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 the GPC method. Table 1 shows the results. Next, a positive-type radiation-sensitive resin composition solution was prepared in the same manner as in Example 1 except that the kind and the amount of the 1,2-quinonediazide compound shown in Table 1 were used, and filtration was performed to evaluate the resist performance. Was. Table 1 shows the results. All were excellent in sensitivity, resolution, developability and heat resistance.

Example 5 A positive-type radiation-sensitive resin composition was obtained in the same manner as in Example 1 except that the novolak resin obtained in Example 1 and the 1,2-quinonediazide compound of the kind and amount shown in Table 1 were used. A solution was prepared and filtered, and the resist performance was evaluated. Table 1 shows the results. All were excellent in sensitivity, resolution, developability and heat resistance.

Comparative Example 1 In the same separable flask as in Example 1, 648 g (6 mol) of m-cresol, 488 g (4 mol) of 3,5-dimethylphenol having high reaction activity, 770 g of a 37% by weight aqueous solution of formaldehyde and shu 8 g of acid was charged at once, the separable flask was immersed in an oil bath,
The reaction was carried out for 2 hours while maintaining the temperature at 0 ° C., and then 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. Next, a composition solution was prepared in the same manner as in Example 1 except that the kind and addition amount of the 1,2-quinonediazide compound shown in Table 1 were used, followed by filtration and evaluation of the resist performance. The results are shown in Table 1. As a result, the sensitivity, resolution and developability were inferior to those of the examples.

Comparative Examples 2 and 3 Various phenols shown in Table 1 were used.
A novolak resin was synthesized in the same manner as described above, and the molecular weight distribution of the novolak resin was measured by the GPC method. Table 1 shows the results.
Shown in Next, the types and addition amounts of 1,2-
Using a quinonediazide compound, a positive radiation-sensitive resin composition solution was prepared and filtered in the same manner as in Example 1 except for evaluating the resist performance. The results are shown in Table 1. As a result, the sensitivity, resolution and developability were inferior to those of the examples.

[0039]

[Table 1]

From the results shown in Table 1, the positive radiation-sensitive resin composition containing the alkali-soluble novolak resin of the present invention was
It can be seen that the balance between sensitivity, resolution, developability and heat resistance is excellent. Example 6 A positive-type radiation-sensitive resin composition solution was prepared in the same manner as in Example 1 except that the novolak resin obtained in Example 1 and the 1,2-quinonediazide compound of the type and addition amount shown in Table 2 were used. It was prepared, filtered, and evaluated for resist performance. Table 2 shows the results. All were excellent in sensitivity, resolution, developability and heat resistance.

Example 7 A positive-type radiation-sensitive resin composition was prepared in the same manner as in Example 1 except that the novolak resin obtained in Example 2 and the 1,2-quinonediazide compound of the type and amount shown in Table 2 were used. A solution was prepared and filtered, and the resist performance was evaluated. Table 2 shows the results. All were excellent in sensitivity, resolution, developability and heat resistance.

Examples 8 and 9 Positive radiation sensitivity was obtained in the same manner as in Example 1 except that the novolak resin obtained in Example 3 and the type and amount of 1,2-quinonediazide compound shown in Table 2 were used. A resin composition solution was prepared, filtered, and evaluated for resist performance. Table 2 shows the results. All were excellent in sensitivity, resolution, developability and heat resistance.

Examples 10 and 11 In the same separable flask as in Example 1, 432 g (4 mol) of m-cresol, 736 g (1 mol) of 2,3,5-trimethylphenol, 892 g of a 37% by weight aqueous solution of formaldehyde and shu 3.0 g of acid was charged, the separable flask was immersed in an oil bath, and reacted for 3 hours while maintaining the internal temperature at 100 ° C., and then m-cresol 1 was further added.
08 g (1 mol) and 544 g (4 mol) of 2,3,5-trimethylphenol were continuously charged into the separable flask as the reaction progressed, and reacted for 2 hours. afterwards,
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 the GPC method.
Table 2 shows the results. Next, a positive-type radiation-sensitive resin composition solution was prepared in the same manner as in Example 1 except for using the 1,2-quinonediazide compound of the kind and the addition amount shown in Table 2, filtered, and evaluated for resist performance. Was. Table 2 shows the results. All were excellent in sensitivity, resolution, developability and heat resistance.

Examples 12 and 13 In the same separable flask as in Example 1, 108 g (1 mol) of m-cresol, 3,5-dimethylphenol 4
88 g (4 mol), 770 g of a 37% by weight aqueous solution of formaldehyde and 0.8 g of oxalic acid were charged, the separable flask was immersed in an oil bath, and the reaction was carried out for 0.5 hour while maintaining the internal temperature at 100 ° C. Cresol 43
2 g (4 mol), 122 g of 3,5-dimethylphenol
(1 mol) was continuously charged into a separable flask as the reaction proceeded, and reacted for 1.5 hours. Then, a novolak resin was synthesized in the same manner as in Example 1, and the GPC
The molecular weight distribution of the novolak resin was measured by the method. Table 2 shows the results. Next, as shown in Table 2,
A positive radiation-sensitive resin composition solution was prepared and filtered in the same manner as in Example 1 except that a 2-quinonediazide compound was used, and the resist performance was evaluated. Table 2 shows the results. All were excellent in sensitivity, resolution, developability and heat resistance.

[0045]

[Table 2]

[0046]

The alkali-soluble novolak resin of the present invention exhibits excellent resolution, sensitivity, developability and heat resistance in the presence of a 1,2-quinonediazide compound, and furthermore has a positive resist excellent in dry etching resistance. Can be obtained.

Claims (2)

[Claims] 1. 30-90 mol% of m-cresol and a compound of the general formula (I) Wherein, X is _{-CH 3, -C 2 H 5,} -C (C
H _{3) 3,} means -CO ₂ CH ₃ or -CO ₂ C ₂ H _5, except 3 ≧ n ≧ 1,3 ≧ m ≧ 1 and is] in compounds represented (but m- cresol) 70 Obtained by subjecting a phenol containing 10 to 10 mol% to a condensation reaction with formaldehyde, the condensation reaction being carried out by a method of adding the phenol with the progress of the reaction, and gel permeation using monodisperse polystyrene as a standard. Chromatograph (GP
The polystyrene equivalent molecular weight determined by the method C) is 6,30.
0-25,000, 2,500-6,000 and 15
When the maximum height values of the peaks in the range of 0 to 900 are a, b and c, respectively, a / b = 0 to 1.5 and c / b = 0.5 to 1.5. An alkali-soluble novolak resin characterized in that: 2. The alkali-soluble novolak resin according to claim 1, which is used for a positive radiation-sensitive resin composition.