JPH05303197A - Positive photoresist composition - Google Patents

Abstract

PURPOSE:To obtain a high-sensitivity resist pattern excellent in resolving power, developability and heat resistance by using an alkali-soluble resin, a quinone diazide and a specified compd. CONSTITUTION:An alkali-soluble resin, a quinone diazide compd. and a compd. shown by the formula are incorporated into the composition. In the formula, R1 to R5 are hydrogen atom, hydroxyl, halogen atom, alkyl, alkoxyl and alkenyls, and at least one among R1 to R5 is hydroxyl. The compd. shown by the formula is obtained by the reaction of cyanuryl chloride with an aminophenol derivative. 2,4,6-Tris(3'-hydroxyphenyl)-amin(-S-triazine, 2,4,6-Tris(4'- hydroxyphenyl)-amino-S-triazine, 2,4,6-Tris(3'-methyl-4'-hydroxyphenyl)-amino-S- triazine, etc., are exemplified as the compd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation-sensitive positive photoresist composition, and more particularly to a photoresist composition for microfabrication having a high resolution and sensitivity and a good pattern cross-sectional shape. It is a thing. The positive type photoresist according to the present invention is a semiconductor wafer,
It is applied to a substrate of glass, ceramics, metal or the like by spin coating or roller coating to a thickness of 0.5 to 3 μm. After that, it is heated and dried, and a circuit pattern or the like is baked by irradiation of ultraviolet rays or the like through an exposure mask and developed to form a positive image. Further, by etching this positive image as a mask, a pattern can be processed on the substrate. IC is a typical application field
Etc., semiconductor manufacturing process, liquid crystal, circuit board manufacturing such as thermal head, and other photo-ablation process.

[0002]

2. Description of the Related Art As a positive photoresist composition,
Generally, a composition containing an alkali-soluble resin and a naphthoquinonediazide compound as a photosensitive material is used. For example, US Pat. No. 3,666,473 as “Novolak type phenol resin / naphthoquinone diazide substituted compound”
No., USP-4,115,128 and USP-4,17
No. 3,470, etc., and the most typical composition is "cresol-formaldehyde novolak resin /
An example of "trihydroxybenzophenone-1,2 naphthoquinone diazide sulfonate" is Thompson "Introduction Tou Microlithography".
(LF Thompson "Introducio
n to Microlitho-graphy ”)
(ACS publication, No. 219, P112 to 121). Novolac resin as a binder is particularly useful for this application because it can be dissolved in an alkaline aqueous solution without swelling, and when it is used as a mask for etching, it gives a high resistance to plasma etching. Is. Further, the naphthoquinonediazide compound used for the photosensitive material acts as a dissolution inhibitor which lowers the alkali solubility of the novolak resin by itself, but when decomposed by light irradiation, an alkali-soluble substance is generated and rather the alkali solubility of the novolak resin is increased. It is unique in that it acts to enhance it, and is particularly useful as a photosensitive material for a positive photoresist because of its large change in properties with respect to light. From this point of view, many positive photoresists containing a novolak resin and a naphthoquinonediazide type photosensitive material have been developed and put to practical use from the viewpoint of 1.5 μm to 2 μm.
We have achieved sufficient results in line width processing down to about μm.

However, the degree of integration of integrated circuits is increasing more and more, and in the manufacture of semiconductor substrates such as VLSIs,
It has become necessary to process an ultrafine pattern having a line width of μm or less. For such applications, there is a demand for a photoresist having a particularly high resolution, a high pattern shape reproducibility for accurately copying the shape of an exposure mask, and a high sensitivity from the viewpoint of high productivity. Further, the etching method has been changed from the conventional wet etching method to the dry etching method in order to increase the degree of integration of the integrated circuit, but the temperature of the resist increases during the dry etching, so that thermal deformation or the like occurs. The resist is required to have high heat resistance so as not to cause this.

In order to improve the heat resistance of the resist, a resin containing no component having a weight average molecular weight of 2000 or less is used (JP-A-60-97347), and the total content of monomers to trimers is 10% by weight or less. A technique using a resin (JP-A-60-189739) has been disclosed.
However, when the above-mentioned resin from which the low molecular weight component is removed or reduced is used, there is a problem that the sensitivity is usually lowered and the throughput in device production is lowered.
Attempts have also been made to improve the sensitivity and developability of the resist by adding a specific compound to the resist composition. For example, JP-A-61-141441 discloses a positive photoresist composition containing trihydroxybenzophenone. Although the positive type photoresist containing trihydroxybenzophenone is improved in sensitivity and developability, the addition of trihydroxybenzophenone causes a problem that heat resistance is deteriorated.

Further, JP-A 64-44439 and JP-A-1
-177032, 1-282748, 2-1035
No. 0 shows an idea of adding an aromatic polyhydroxy compound other than trihydroxybenzophenone to increase the sensitivity without deteriorating the heat resistance, but it is not always sufficient to improve the developability. I can not say.

[0006]

SUMMARY OF THE INVENTION Therefore, the object of the present invention is to provide a positive photoresist composition capable of obtaining a resist pattern having high sensitivity, excellent resolution, developability and heat resistance, particularly in the production of semiconductor devices and the like. To provide things.

[0007]

Means for Solving the Problems The inventors of the present invention have made extensive studies, paying attention to the above-mentioned characteristics, and as a result, achieved the above object by using an alkali-soluble resin, a quinonediazide compound and a compound having a specific structural formula. They have found that they can obtain the present invention, and have completed the present invention based on this finding. That is, the object of the present invention has been achieved by a positive photoresist composition containing an alkali-soluble resin, a quinonediazide compound and a compound represented by the following general formula (I).

[0008]

[Chemical 2]

R _{1 to} R ₅ may be the same or different and represent a hydrogen atom, a hydroxyl group, a halogen atom, an alkyl group, an alkoxy group or an alkenyl group. However, at least one of R _{1 to} R ₅ is a hydroxyl group. Hereinafter, the present invention will be described in detail.

In R _{1 to} R ₅ of the above general formula (I), the halogen atom is a chlorine atom, a bromine atom or an iodine atom, and the alkyl group is a methyl group, an ethyl group, a propyl group, an n-butyl group, An alkyl group having 1 to 4 carbon atoms such as an isobutyl group, a sec-butyl group or a t-butyl group, an alkoxy group is a methoxy group, an ethoxy group, a hydroxyethoxy group, a propoxy group, a hydroxypropoxy group, an isopropoxy group, An alkoxy group having 1 to 4 carbon atoms such as an n-butoxy group, an isobutoxy group, a sec-butoxy group or a t-butoxy group is preferable. The alkenyl group is preferably a C2-C4 alkenyl group such as a vinyl group, a propenyl group, an allyl group or a butenyl group.

The compound represented by the general formula (I) can be obtained, for example, by the method described in European Patent 208376, that is, by reacting cyanuric chloride with an aminophenol derivative. Specific examples of the compound thus obtained include 2,4,6-tris (3'-hydroxyphenyl) -amino-S-triazine and 2,4,6-tris (4'-hydroxyphenyl). -Amino-S-triazine, 2,4,6-tris (3'-methyl-4'-hydroxyphenyl) -amino-S-triazine, 2,4,6
-Tris (3 ', 5'-dimethyl-4'-hydroxyphenyl) -amino-S-triazine, 2,4,6-tris (3'-chloro-4'-hydroxyphenyl) -amino-S- Triazine, 2,4,6-tris (3'5'-
Dichloro-4 '-) hydroxyphenyl-amino-S-
Triazine, 2,4,6-tris (3'5'-dibromo-4'-hydroxyphenyl) -amino-S-triazine, 2,4,6-tris (3'-chloro-4'-methylphenyl) Phenyl) -amino-S-triazine, 2,
4,6-Tris (3'-bromo-4'-hydroxy-
5'-methylphenyl) -amino-S-triazine and the like can be mentioned, but the invention is not limited thereto.

These compounds may be used alone or in combination of two or more. The compounding amount of the compound represented by the general formula (I) is usually 150 parts by weight or less, preferably 5 to 100 parts by weight, based on 100 parts by weight of the quinonediazide compound. If the use ratio is less than 5 parts by weight, the effect of increasing the sensitivity is not substantially obtained, and if it exceeds 150 parts by weight, the residual film rate is remarkably reduced.

Examples of the alkali-soluble resin used in the present invention include novolak resin, acetone-pyrogallol resin, polyhydroxystyrene and derivatives thereof. Among these, novolak resin is particularly preferable,
It can be obtained by addition-condensing an aldehyde with a predetermined monomer as a main component in the presence of an acidic catalyst. Specific monomers include phenol, m-cresol, p
-Cresols, cresols such as o-cresol, 2,
Xylenols such as 5-xylenol, 3,5-xylenol, 3,4-xylenol, and 2,3-xylenol,
Alkylphenols such as m-ethylphenol, p-ethylphenol, o-ethylphenol, pt-butylphenol, p-methoxyphenol, m-methoxyphenol, 3,5-dimethoxyphenol, 2-methoxy-4- Alkoxyphenols such as methylphenol, m-ethoxyphenol, p-ethoxyphenol, m-propoxyphenol, p-propoxyphenol, m-butoxyphenol, p-butoxyphenol and bisalkyl such as 2-methyl-4-isopropylphenol. Phenols, m-chlorophenol, p-chlorophenol, o-chlorophenol, dihydroxybiphenyl, bisphenol A, phenylphenol,
Hydroxy aromatic compounds such as resorcinol and naphthol may be used alone or in combination of two or more, but are not limited thereto.

Examples of the aldehydes include formaldehyde, paraformaldehyde, acetaldehyde, propylaldehyde, benzaldehyde, phenylacetaldehyde, α-phenylpropylaldehyde, β-phenylpropylaldehyde, o-hydroxybenzaldehyde, 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, furfural,
Chloroacetaldehyde and acetals thereof such as chloroacetaldehyde diethyl acetal can be used, and of these, formaldehyde is preferably used. These aldehydes are
They may be used alone or in combination of two or more. As the acidic catalyst, hydrochloric acid, sulfuric acid, formic acid, acetic acid, oxalic acid or the like can be used. The weight average molecular weight of the thus obtained novolak resin is preferably in the range of 2,000 to 30,000. If it is less than 2000, the film loss of the unexposed area after development is large, and if it exceeds 30,000, the developing speed becomes slow. Particularly preferred is 6000-200
The range is 00. Here, the weight average molecular weight is defined as having a polystyrene conversion value of gel permeation chromatography.

As the photosensitive material used in the present invention, an esterified product of the following polyhydroxy compound with 1,2-naphthoquinonediazide-5- (and / or -4-) sulfonyl chloride can be used. Examples of polyhydroxy compounds include, for example, 2,3,4-trihydroxybenzophenone, 2,4,4'-trihydroxybenzophenone, 2,4,6-trihydroxybenzophenone and 2,2,4'-trihydroxybenzophenone.
3,4-trihydroxy-2'-methylbenzophenone,
2,3,4,4'-tetrahydroxybenzophenone, 2,
2 ', 4,4'-tetrahydroxybenzophenone, 2,4,
6,3 ', 4'-pentahydroxybenzophenone, 2,3,
4,2 ', 4'-pentahydroxybenzophenone, 2,3,
4,2 ', 5'-pentahydroxybenzophenone, 2,4,
6,3 ', 4', 5'-hexahydroxybenzophenone,
Polyhydroxybenzophenones such as 2,3,4,3 ′, 4 ′, 5′-hexahydroxybenzophenone, 2,3,4-trihydroxyacetophenone, 2,3,4-trihydroxyphenone Polyhydroxyphenyl alkyl ketones such as enyl pentyl ketone, 2,3,4-trihydroxyphenylhexyl ketone, bis (2,4-dihydroxyphenyl) methane, bis (2,3,4-trihydroxyphenyl) ) Methane, bis (2,4-dihydroxyphenyl) propane-1, bis (2,3,4-trihydroxyphenyl)
Propane-1, bis ((poly) hydroxyphenyl) alkanes such as nordihydroguaiaretic acid, 3,4,5
-Propyl trihydroxybenzoate, phenyl 2,3,4-trihydroxybenzoate, phenyl 3,3,5-trihydroxybenzoate, and other polyhydroxybenzoates, bis (2,3,4-trihydroxybenzoyl) ) Methane, bis (3-acetyl-4,5,6-trihydroxyphenyl) -methane, bis (2,3,4-trihydroxybenzoyl) benzene, bis (2,4,6-trihydroxybenzoyl) benzene, etc. Bis (polyhydroxybenzoyl) alkane or bis (polyhydroxybenzoyl)
Aryls, ethylene glycol-di (3,5-dihydroxybenzoate), ethylene glycol-di (3,
Alkylene-di (polyhydroxybenzoates) such as 4,5-trihydroxybenzoate), 2,3,4-biphenyltriol, 3,4,5-biphenyltriol, 3,5,3 ', 5'- Biphenyl tetrol 2,4,
2 ', 4'-biphenyl tetrol, 2,4,6,3', 5'-
Polyhydroxybiphenyl such as biphenyl pentol, 2,4,6,2 ', 4', 6'-biphenyl hexol, 2,3,4,2 ', 3', 4'-biphenyl hexol Bis (polyhydroxy) sulfides such as 4,4′-thiobis (1,3-dihydroxy) benzene and bis (polyhydroxyphenyl) such as 2,2 ′, 4,4′-tetrahydroxydiphenyl ether Ethers, bis (polyhydroxyphenyl) sulfoxides such as 2,2 ′, 4,4′-tetrahydroxydiphenyl sulfoxide, and bis (such as 2,2 ′, 4,4′-diphenyl sulfone) Polyhydroxyphenyl) sulfones, 4,4 ′, 3 ″, 4 ″ -tetrahydroxy-3,5,3 ′, 5′-tetramethyltriphenylmethane, 4,4 ′, 2 ″, 3 '', 4 ''-pentahydroxy-3,
5,3 ', 5'-tetramethyltriphenylmethane, 2,3,
4,2 ', 3', 4'-hexahydroxy-5,5'-diacetyltriphenylmethane, 2,3,4,2 ', 3', 4 ', 3'',
Polyhydroxytrif such as 4 ″ -octahydroxy-5,5′-diacetyltriphenyl methane, 2,4,6,2 ′, 4 ′, 6′-hexahydroxy-5,5′-dipropionyltriphenyl methane Enenylmethanes, 3,3,3 ', 3'-tetramethyl-1,1'-spirobi-indane-5,6,5',
6'-tetrol, 3,3,3 ', 3'-tetramethyl-1,
1'-spirobi-indane-5,6,7,5 ', 6', 7'-hexool, 3,3,3 ', 3'-tetramethyl-1,1'-
Spirobi-indane-4,5,6,4 ', 5', 6'-hexool, 3,3,3 ', 3'-tetramethyl-1,1'-spirobi-indane-4,5,6,5 Polyhydroxyspirobi-indanes such as ', 6', 7'-hexool, 3,3-bis (3,4-dihydroxyphenyl) phthalide, 3,3-bis (2,3,4-trihydroxyphenyl) (Enyl) phthalide,
Polyhydroxyphthalides such as 3 ', 4', 5 ', 6'-tetrahydroxyspiro [phthalide-3,9'-xanthene], 2- (3,4-dihydroxyphenyl) -3,5,
7-trihydroxybenzopyran, 2- (3,4,5-
Trihydroxyphenyl) -3,5,7-trihydroxybenzopyran, 2- (3,4-dihydroxyphenyl) -3- (3,4,5-trihydroxybenzoyloxy) -5,7-dihydroxybenzo Piran, 2-
(3,4,5-Trihydroxyphenyl) -3- (3,3
4,5-Trihydroxybenzoyloxy) -5,7-
Polyhydroxybenzopyrans such as dihydroxybenzopyran or flavono dyes such as morin, quercetin and rutin can be used. Further, a low-nucleus body of a phenol resin such as a novolak resin can also be used. The naphthoquinone diazide ester photosensitive materials of these polyhydroxy compounds are used alone or in combination of two or more kinds. The ratio of the photosensitive material to the alkali-soluble resin used is 5 to 100 parts by weight, preferably 10 to 50 parts by weight, based on 100 parts by weight of the resin. If this usage ratio is less than 5 parts by weight, the residual film ratio will be significantly reduced, while
If it exceeds the amount by weight, the sensitivity and the solubility in a solvent are lowered.

The composition of the present invention may further contain other polyhydroxy compounds in order to accelerate the dissolution in the developing solution. Preferred polyhydroxy compounds include:
Phenols, resorcin, phloroglucin, 2,3,4
-Trihydroxybenzophenone, 2,3,4,4'-tetrahydroxybenzophenone, 2,3,4,3 ', 4',
5'-hexahydroxybenzophenone, acetone-pyrogallol condensation resin, phlorogluside, 2,4,2 ',
4'-biphenyl tetrol, 4,4'-thiobis (1,
3-dihydroxy) benzene, 2,2 ', 4,4'-tetrahydroxydiphenyl ether, 2,2', 4,4'-
Tetrahydroxydiphenyl sulfoxide, 2,2 ',
4,4′-Tetrahydroxydiphenyl sulfone, bis (2,4-dihydroxyphenyl) methane, bis (2,3,4-trihydroxyphenyl) methane, bisphenol A, bisphenol AF, bisphenol S , Bisphenol F, and the like. These polyhydroxy compounds are usually 50 parts by weight or less based on 100 parts by weight of the polyhydroxy compound of the present invention,
It can be preferably mixed in a proportion of 30 parts by weight or less.

As a solvent for dissolving the photosensitive material of the present invention and the alkali-soluble novolak resin, ketones such as methyl ethyl ketone and cyclohexanone, 4-ethoxy-2
-Ketoethers such as butanone, 4-methoxy-4-methyl-2-pentanone, alcohol ethers such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether, ethers such as dioxane and ethylene glycol dimethyl ether, methyl cellosolve acetate, ethyl Cellosolve esters such as cellosolve acetate, fatty acid esters such as butyl acetate, methyl lactate, ethyl lactate, halogenated hydrocarbons such as 1,1,2-trichloroethylene, dimethylacetamide, N-
Examples thereof include highly polar solvents such as methylpyrrolidone, dimethylformamide and dimethylsulfoxide. These solvents may be used alone or as a mixture of a plurality of solvents.

A surfactant may be added to the positive photoresist composition of the present invention in order to further improve the coating properties such as striation. Examples of the surfactant include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, polyoxyethylene oleyl ether, and other polyoxyethylene alkyl ethers, polyoxyethylene octylphenol ether, polyoxyethylene nonyl. Polyoxyethylene alkyl allyl ethers such as phenol ethers, polyoxyethylene / polyoxypropylene block copolymers, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, sorbitan tristea Sorbitan fatty acid esters such as rate, polyoxyethylene sorbitan monolaurate, polyoxyethylene sol Monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, polyoxyethylene sorbitan tristearate, etc., polyoxyethylene sorbitan fatty acid esters nonionic surface active agents such as, Efutotsupu EF
301, EF303, EF352 (manufactured by Shin-Akita Kasei Co., Ltd.),
Megafacs F171, F173 (Dainippon Ink Co., Ltd.)
), Fluorard FC430, FC431 (Sumitomo 3M Limited), Asahi Guard AG710, Surflon S
-382, SC101, SC102, SC103, SC10
4, SC105, SC106 (manufactured by Asahi Glass Co., Ltd.), fluorine-based surfactant, organosiloxane polymer KP341
(Manufactured by Shin-Etsu Chemical Co., Ltd.) or acrylic acid-based or methacrylic acid-based (co) polymerized Polyflow No. 75, No. 95
(Kyoeisha Yushi Kagaku Kogyo Co., Ltd.) and the like can be mentioned. The amount of these surfactants to be blended is 100% for the alkali-soluble resin and quinonediazide compound in the composition of the present invention.
It is usually 2 parts by weight or less, preferably 1 part by weight or less, per part by weight. These surfactants may be added alone or in some combinations.

The developer for the positive photoresist composition of the present invention includes sodium hydroxide, potassium hydroxide,
Inorganic alkalis such as sodium carbonate, sodium silicate, sodium metasilicate and aqueous ammonia, primary amines such as ethylamine and n-propylamine, secondary amines such as diethylamine and di-n-butylamine, triethylamine and methyldiethylamine. Tertiary amines such as
Use aqueous solutions of alcohol amines such as dimethylethanolamine and triethanolamine, quaternary ammonium salts such as tetramethylammonium hydroxide and tetraethylammonium hydroxide, cyclic amines such as pyrrole and piperidine, and alkalis such as You can Further, an appropriate amount of alcohols and surfactants may be added to the above aqueous solution of alkalis for use.

The positive photoresist composition of the present invention may contain a dye, a plasticizer and an adhesion aid, if necessary. Specific examples thereof include dyes such as methyl violet, crystal violet and malachite green, stearic acid, acetal resins, phenoxy resins, plasticizers such as alkyd resins, and adhesion promoters such as hexamethyldisilazane and chloromethylsilane. is there.

After applying the above positive photoresist composition onto a substrate (eg, silicon / silicon dioxide coating) used for the production of precision integrated circuit devices by a suitable coating method such as a spinner or a coater, a predetermined coating is performed. A good resist can be obtained by exposing through a mask and developing. Examples of the present invention will be shown below, but the present invention is not limited thereto. Unless otherwise specified,% means% by weight.

[0022]

【Example】

(1) Synthesis of novolak resin (A) m-cresol 40 g, p-cresol 60 g, 37%
54.0 g of formalin aqueous solution and 0.05 g of oxalic acid were charged into a three-necked flask, heated to 100 ° C. with stirring, and reacted for 7 hours. After the reaction, cool to room temperature and 30m
The pressure was reduced to mHg. Then, the temperature was gradually raised to 150 ° C. to remove water and unreacted monomers. The obtained novolak resin had an average molecular weight of 7,900 (in terms of polystyrene).

(2) Synthesis of novolak resin (B) 50% by weight of m-cresol and 50% by weight of p-cresol
And a cresol novolak resin (polystyrene-equivalent molecular weight 9400) synthesized in the same manner as (1) above using an aqueous formalin solution, "Experimental Method for Polymer Synthesis," p. 32 (Masayoshi Kinoshita, Takayuki Otsu: Kagaku Dojin (1973). )), The low molecular weight components were separated to obtain a cresol novolak resin having a molecular weight of 10060 in terms of polystyrene.

(3) Synthesis of Photosensitive Material a 2,3,4-trihydroxybenzophenone 11.5 g,
30.2 g of 1,2-naphthoquinonediazide-5-sulfonyl chloride and 300 ml of acetone were charged into a three-necked flask and uniformly dissolved. Then triethylamine /
A mixed solution of acetone = 11.4 g / 50 ml was gradually added dropwise and reacted at 25 ° C. for 3 hours. The reaction mixture was poured into 1500 ml of a 1% aqueous hydrochloric acid solution, the precipitate formed was filtered off,
After washing with water and drying (40 ° C), 1,2-naphthoquinonediazide-5 of 2,3,4-trihydroxybenzophenone-5
-29.8 g of sulfonic acid ester are obtained.

(4) Synthesis of Photosensitive Material b 2,3,4,4'-Tetrahydroxybenzophenone 1
2.3 g of 1,2-naphthoquinonediazide-5-sulfonyl chloride and 40.3 g of acetone and 300 ml of acetone were charged into a three-necked flask and uniformly dissolved. Then, a mixed solution of triethylamine / acetone = 15.2 g / 50 ml was gradually added dropwise and reacted at 25 ° C. for 3 hours. The reaction mixture was poured into 1500 ml of a 1% hydrochloric acid aqueous solution, the precipitate formed was filtered off, washed with water and dried (40 ° C.), and then 2, 3, 4,
39.7 g of 1,2-naphthoquinonediazide-5-sulfonic acid ester of 4'-tetrahydroxybenzophenone
Got

(5) Compound [Ia]: Synthesis of 2,4,6-tris (4'-hydroxyphenyl) -amino-S-triazine p-Aminophenol 6 in 550 ml of acetone.
2.1 g was placed in a three-necked flask and uniformly dissolved. Then cyanuric chloride / acetone = 17.5 g / 150 ml
Was gradually added dropwise over about 1 hour and refluxed at 56 ° C. for 3 hours. The reaction mixture was filtered off, washed with water, dried,
36.3 g of 2,4,6-tris (4'-hydroxyphenyl) -amino-S-triazine was obtained. The white crystals have a purity of 99.8% by gas chromatography,
It had a melting point of 297 ° C.

(6) Compound [Ib]: Synthesis of 2,4,6-tris (3'-hydroxyphenyl) -amino-S-triazine m-amino instead of 62.1 g of p-aminophenol 2,4,6-Tris (3'-hydroxyphenyl) -amino-S-triazine was synthesized in the same manner as in (5) except that 62.1 g of phenol was used. The white crystals showed a purity of 98.7% by gas chromatography and had a melting point of 289 ° C.

(7) Preparation and Evaluation of Positive Photoresist Composition Cresol novolac resin (A) or (B) obtained in the above (1) or (2), obtained in (3) or (4) above. Photosensitive Material a or b and Additives (1) to Table 1
(5) was dissolved in 15 g of ethyl cellosolve acetate in the ratio shown in Table 2 and filtered using a 0.2 μm microfilter to prepare a photoresist composition. This photoresist composition was applied to a silicon wafer using a spinner and dried on a vacuum hot plate at 100 ° C. for 90 seconds to obtain a resist film having a thickness of 1.2 μm. Next, it was exposed through a test chat mask using a reduction projection exposure apparatus FPA-1550 manufactured by Canon Inc., developed with a 2.38% tetramethylammonium hydroxide aqueous solution for 1 minute, washed with water for 30 seconds and dried.

The resist pattern of the silicon wafer thus obtained was observed with a scanning electron microscope to evaluate the resist. The results are shown in Table 3.

[0030]

[Table 1]

[0031]

[Table 2]

[0032]

[Table 3]

The sensitivity was defined as the reciprocal of the exposure dose for reproducing a 0.70 μm mask pattern, and shown as a relative value with respect to the sensitivity of Comparative Example 1. The residual film rate was expressed as a percentage of the ratio of the unexposed area before and after development. The resolving power represents a limiting resolving power at an exposure amount that reproduces a 0.70 μm mask pattern. The heat resistance showed the temperature at which the resist pattern-patterned silicon wafer was baked in a convection oven for 30 minutes and the pattern was not deformed. The shape of the resist is represented by the angle (θ) formed by the resist wall surface and the plane of the silicon wafer in the 0.70 μm resist pattern cross section. Regarding the developability, the case where the peeling of the surface layer and the film residue were not observed and was good was represented by ◯, the case where a large amount was observed was represented by x, and the case where a little was observed was represented by Δ. As can be seen from this, the resists using the additives (1) and (2) of the present invention were excellent in sensitivity, residual film rate, resolution, heat resistance, resist shape and developability.

[0034]

The positive photoresist containing the additive of the present invention is excellent in resolution, sensitivity, developability and heat resistance and is suitable for use as a fine processing photoresist.

Claims (1)

[Claims] 1. A positive photoresist composition comprising an alkali-soluble resin, a quinonediazide compound and a compound represented by the following general formula (I). [Chemical 1] Here, R _{1 to} R ₅ may be the same or different and represent a hydrogen atom, a hydroxyl group, a halogen atom, an alkyl group, an alkoxy group or an alkenyl group. However, at least one of R _{1 to} R ₅ is a hydroxyl group.