JP2753917B2 - Positive photoresist composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positive photoresist composition which is sensitive to radiation, and more particularly to a photoresist composition for microfabrication having a high resolving power and sensitivity and a good pattern cross-sectional shape. Things. The positive photoresist according to the present invention is a semiconductor wafer,
It is applied to a substrate of glass, ceramics, metal or the like by a spin coating method or a roller coating method to a thickness of 0.5 to 3 μm. Thereafter, the circuit pattern is heated, dried, printed with a circuit pattern or the like through an exposure mask by ultraviolet irradiation or the like, and developed to form a positive image. Further, by performing etching using the positive image as a mask, a pattern can be processed on the substrate. Typical applications are IC
And the like, manufacturing of circuit boards such as liquid crystals and thermal heads, and other photo-fabrication processes.

[0002]

2. Description of the Related Art Positive photoresist compositions include:
In general, 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 phenolic resin / naphthoquinonediazide-substituted compound”
No., USP-4,115,128 and USP-4,17
No. 3,470, and the most typical composition is a novolak resin composed of cresol-formaldehyde /
An example of "trihydroxybenzophenone-1,2 naphthoquinonediazidosulfonic acid ester" is Thompson "Introduction to microlithography".
(LF Thompson "Introduction"
n to Microlitho-graphy ")
(ACS Publishing, No. 219, pp. 112-121). Novolak resin as a binder is soluble in an alkaline aqueous solution without swelling, and is particularly useful in this application because it gives high resistance to plasma etching especially when the generated image is used as a mask for etching. It is. Further, the naphthoquinonediazide compound used in the photosensitive material itself acts as a dissolution inhibitor that reduces the alkali solubility of the novolak resin, but when decomposed by irradiation with light, generates an alkali-soluble substance and rather increases the alkali solubility of the novolak resin. 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 property change to light. From this point of view, many positive photoresists containing a novolak resin and a naphthoquinonediazide-based photosensitive material have been developed and put into practical use.
Sufficient results have been achieved in line width processing down to about μm.

[0003] However, the degree of integration of integrated circuits is increasing more and more, and in the manufacture of semiconductor substrates such as VLSI, one is required.
Processing of an ultrafine pattern having a line width of μm or less has been required. In such applications, there is a demand for a photoresist having particularly high resolution, high pattern shape reproduction accuracy for accurately capturing the shape of an exposure mask, and high sensitivity from the viewpoint of high productivity. In addition, in order to increase the degree of integration of integrated circuits, the etching method has shifted from the conventional wet etching method to a dry etching method. High heat resistance is required for the resist so that it does not occur.

In order to improve the heat resistance of the resist, a resin containing no component having a weight average molecular weight of 2,000 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) is disclosed.
However, when a resin from which the above low molecular weight component is removed or reduced is used, there is a problem that the sensitivity is usually lowered and the throughput in the device manufacturing is lowered.
Attempts have also been made to improve the sensitivity and developability of the resist by incorporating a specific compound into the resist composition. For example, Japanese Patent Application Laid-Open No. 61-141441 discloses a positive photoresist composition containing trihydroxybenzophenone. The positive photoresist containing trihydroxybenzophenone has improved sensitivity and developability, but has the problem that the addition of trihydroxybenzophenone deteriorates heat resistance.

Further, Japanese Patent Application Laid-Open Nos.
-177032, 1-2780748, 2-1035
No. 0 shows a technique for increasing the sensitivity without deteriorating the heat resistance by adding an aromatic polyhydroxy compound other than trihydroxybenzophenone, but the improvement of the developability is not necessarily sufficient. I can not say.

[0006]

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

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies while paying attention to the above characteristics, and as a result, have achieved the above object by using an alkali-soluble resin, a quinonediazide compound and a compound having a specific structural formula. The inventors have found that the present invention has been achieved, 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 comprising an alkali-soluble resin, a quinonediazide compound and a compound represented by the following general formula (I).

[0008]

Embedded image Here, R _{1 to} R ₄ may be the same or different, and may be a hydrogen atom, a hydroxyl group, a halogen atom, an alkyl group, an alkoxy group or an alkenyl group, R ₅ and R ₆ : a hydrogen atom, an alkyl group or a) c: 0 or 1, b: 0 or an integer of 1 to 4 Where b = 0,
When a = 1, when both R ₅ and R ₆ are hydrogen atoms
And one of R ₅ and R ₆ is a hydrogen atom, and the other is
Represents an alkyl group having 1 to 4 carbon atoms. Also,
When b = 1 and a = 1 , both R ₅ and R _{6 represent} a hydrogen atom.
Excluding the case. When b = 2, a = 1, and c = 0, R
Except when both ₅ and R ₆ represent a hydrogen atom.

Hereinafter, the present invention will be described in detail.

In R _{1 to} R ₄ of the general formula (I), a halogen atom is chlorine, bromine or iodine, and an alkyl is methyl, ethyl, propyl, n-butyl, An alkyl group having 1 to 4 carbon atoms such as an isobutyl group, a sec-butyl group or a t-butyl group, wherein the 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 preferred.
As the alkenyl group, an alkenyl group having 2 to 4 carbon atoms such as a vinyl group, a propenyl group, an allyl group or a butenyl group is preferable.

The compound represented by the general formula (I) is described, for example, in Chemishe Berichte 74, 177.
Using a p-hydroxyphenyl ketone compound obtained by the method described on page 2 (1941), JP-A-55-16
2728, that is, by reacting a carbonyl precursor with a phenol derivative under acidic or alkaline conditions. Further, it can be obtained by reacting a haloketone compound with a phenol derivative under acidic conditions, for example, by the method described in US Pat. When the reaction is performed under acidic conditions, it is preferable to use a catalyst containing a mercapto group. Specific examples of the catalyst containing a mercapto group include ethanethiol, 1-butanethiol, thiophenol, and mercaptoacetic acid, but are not limited thereto. The condensation reaction is preferably carried out using at least a stoichiometric amount of a phenol reaction component. Reaction temperature is from room temperature to 10
A temperature of 0 ° C. or higher is preferred. The progress of the condensation reaction can be easily monitored by chromatography or spectroscopy. For example, infrared spectroscopy can easily be followed by a decrease in the carbonyl absorption band.

The purification of these compounds can be performed by recrystallization, elution chromatography or the like. Suitable solvents for recrystallization are methylene chloride, benzene, cyclohexane,
Methanol, ethanol, and an alcohol-water mixture. Elution chromatography is best performed on alumina or silica with various solvents as eluents.

Specific examples of the compound represented by the general formula (I) thus obtained include the following [Ia] and [I
-C] and the compounds represented by [ Ie] to [Ip], but are not limited thereto. Compounds represented by the following [Ib] and [Id]
Is a reference specific example. These polyhydroxy compounds are used alone or in combination of two or more.

[0014]

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[0015]

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[0016]

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[0017]

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[0018]

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[0019]

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The amount of the compound represented by the general formula (I) is usually 1 to 100 parts by weight of the quinonediazide compound.
It is 50 parts by weight or less, preferably 5 to 100 parts by weight.
If the use ratio is less than 5 parts by weight, the effect of increasing sensitivity is not substantially obtained, and if it exceeds 150 parts by weight, the residual film ratio is remarkably reduced.

Examples of the alkali-soluble resin used in the present invention include a novolak resin, an acetone-pyrogallol resin, polyhydroxystyrene and derivatives thereof. Among these, Novolak resin is particularly preferred,
It is obtained by subjecting a given monomer as a main component to addition condensation with an aldehyde in the presence of an acidic catalyst. Specific monomers include phenol, m-cresol, p
Cresols such as cresol, o-cresol, 2,
Xylenols such as 5-xylenol, 3,5-xylenol, 3,4-xylenol, 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 bisalkyls 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 can 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 and p-hydroxybenzaldehyde. -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 its acetal form, such as chloroacetaldehyde diethyl acetal, can be used, and among these, formaldehyde is preferably used. These aldehydes are
They are used alone or in combination of two or more. As the acidic catalyst, hydrochloric acid, sulfuric acid, formic acid, acetic acid, oxalic acid and 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 portion after development is large, and if it exceeds 30,000, the developing speed is reduced. Particularly preferred are 6000-200
00 range. Here, the weight average molecular weight is defined as a value in terms of polystyrene 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,
3,4-trihydroxy-2′-methylbenzophenone,
2,3,4,4'-tetrahydroxybenzophenone,
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-trihydroxyphen Polyhydroxyphenyl alkyl ketones such as enylpentyl 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)
Bis ((poly) hydroxyphenyl) alkanes such as propane-1, nordihydroguaiaretic acid, 3,4,5
Polyhydroxybenzoic acid esters such as propyl trihydroxybenzoate, phenyl 2,2,3,4-trihydroxybenzoate, phenyl 2,3,4,5-trihydroxybenzoate, 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 biphenylpentol, 2,4,6,2 ', 4', 6'-biphenylhexol, 2,3,4,2 ', 3', 4'-biphenylhexol (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'-tetrahydroxydiphenylsulfoxide and bis (such as 2,2', 4,4'-diphenylsulfone) 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'-diacetyltriphenylmethane, 2,4,6,2 ', 4', 6'-hexahydroxy-5,5'-dipropionyltriphenylmethane Enylmethanes, 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'-hexol, 3,3,3 ', 3'-tetramethyl-1,1'-
Spirobi-indane-4,5,6,4 ', 5', 6'-hexol, 3,3,3 ', 3'-tetramethyl-1,1'-spirobi-indane-4,5,6,5 Polyhydroxyspirobi-indanes such as ', 6', 7'-hexol, 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′-xanthen]; 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 Pyran, 2-
(3,4,5-trihydroxyphenyl) -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 of a phenol resin such as a novolak resin can also be used. These naphthoquinonediazide ester photosensitive materials of the polyhydroxy compound may be used alone or in combination of two or more. The usage ratio of the photosensitive material to the alkali-soluble resin is 5 to 100 parts by weight, preferably 10 to 50 parts by weight, based on 100 parts by weight of the resin. When the use ratio is less than 5 parts by weight, the residual film ratio is remarkably reduced.
If the amount is more than 10 parts by weight, sensitivity and solubility in a solvent are reduced.

In the composition of the present invention, another polyhydroxy compound can be used in combination for further promoting dissolution in a developer. 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'-
Tetrahydroxydiphenylsulfoxide, 2,2 ',
4,4'-tetrahydroxydiphenylsulfone, 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,
Preferably, it can be blended in a proportion of 30 parts by weight or less.

Solvents for dissolving the photosensitive material and the alkali-soluble novolak resin of the present invention include ketones such as methyl ethyl ketone and cyclohexanone, and 4-ethoxy-2.
-Ketoethers such as butanone and 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 and ethyl Cellosolve esters such as cellosolve acetate; fatty acid esters such as butyl acetate, methyl lactate and ethyl lactate; halogenated hydrocarbons such as 1,1,2-trichloroethylene; dimethylacetamide;
Highly polar solvents such as methylpyrrolidone, dimethylformamide, and dimethylsulfoxide can be exemplified. These solvents can 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 coating properties such as striation. Examples of the surfactant include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, polyoxyethylene alkyl ethers such as polyoxyethylene oleyl ether, polyoxyethylene octyl phenol ether, and polyoxyethylene nonyl. Polyoxyethylene alkyl allyl ethers such as phenol ether, polyoxyethylene / polyoxypropylene block copolymers, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, sorbitan tristearate Fatty acid esters such as 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 Chemical Co., Ltd.),
MegaFuck F171, F173 (Dainippon Ink Co., Ltd.)
), Florado FC430, FC431 (manufactured by Sumitomo 3M Limited), Asahi Guard AG710, Surflon S
-382, SC101, SC102, SC103, SC10
4, fluorine-based surfactants such as SC105 and SC106 (manufactured by Asahi Glass Co., Ltd.), 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
(Manufactured by Kyoeisha Yushi Kagaku Kogyo KK) and the like. The amount of these surfactants is determined by the amount of the alkali-soluble resin and the quinonediazide compound in the composition of the present invention.
It is usually at most 2 parts by weight, preferably at most 1 part by weight, per part by weight. These surfactants may be added alone or in some combination.

As a developer for the positive photoresist composition of the present invention, 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 alkali amines such as alcoholamines such as dimethylethanolamine and triethanolamine, quaternary ammonium salts such as tetramethylammonium hydroxide and tetraethylammonium hydroxide, and cyclic amines such as pyrrole and piperidine. Can be. Further, an appropriate amount of an alcohol or a surfactant may be added to the aqueous solution of the above alkalis for use.

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

The positive photoresist composition is applied onto a substrate (eg, silicon / silicon dioxide coating) to be used in the manufacture of precision integrated circuit devices by an appropriate application method such as a spinner or a coater. By exposing and developing through a mask, a good resist can be obtained. Hereinafter, examples of the present invention will be described, but the present invention is not limited thereto. In addition,% shows weight% unless otherwise specified.

[0030]

【Example】

(1) Synthesis of novolak resin (A) 40 g of m-cresol, 60 g of p-cresol, 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. Cool down to room temperature after the reaction, 30m
The pressure was reduced to mHg. Next, 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, 50% by weight of p-cresol
And a cresol novolak resin (molecular weight 9400 in terms of polystyrene) synthesized using a formalin aqueous solution in the same manner as in the above (1), "Experimental Method for Polymer Synthesis", page 32 (Masetsu Kinoshita, Takayuki Otsu: Chemical 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 11.5 g of 2,3,4-trihydroxybenzophenone
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 dropped, and reacted at 25 ° C. for 3 hours. The reaction mixture was poured into 1500 ml of a 1% aqueous hydrochloric acid solution, and the resulting precipitate was separated by filtration.
After washing with water and drying (40 ° C.), 1,2-naphthoquinonediazide-5 of 2,3,4-trihydroxybenzophenone
-29.8 g of sulfonic acid ester were obtained.

(4) Synthesis of Photosensitive Material b 2,3,4,4'-Tetrahydroxybenzophenone 1
2.3 g, 1,2-naphthoquinonediazide-5-sulfonyl chloride (40.3 g) and acetone (300 ml) 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% aqueous hydrochloric acid solution, and the resulting precipitate was separated by filtration, washed with water and dried (40 ° C.), and subjected to 2, 3, 4,
39.7 g of 1,2-naphthoquinonediazide-5-sulfonic acid ester of 4'-tetrahydroxybenzophenone
I got

(5) Synthesis Example 1 Synthesis of Compound [Ib] To 25.4 g (0.20 mol) of dichloroacetone was added 188 g (2.0 mol) of phenol and heated to 45 ° C. Hydrogen chloride gas was introduced into the reaction solution. When the reaction liquid turned yellow, the heating was stopped and the introduction of hydrogen chloride gas was continued for another 2 hours. Thereafter, the red-brown reaction mixture was distilled under reduced pressure to remove excess phenol. The obtained red-brown solid residue was washed with n-hexane, and further subjected to column chromatography (filler: silica gel, eluent: n
-Hexane / ethyl acetate = 2/1). As a result, 72 g of a white powder was obtained. NMR (nuclear magnetic resonance spectrum) confirmed that the powder was 1,2,2,3-tetrakis (4′-hydroxyphenyl) propane [Ib].

(6) Synthesis Example 2 Synthesis of Compound [Ic] 66.5 g of 4-hydroxyphenylpropionic acid (0.
40 mol) and 16.4 g (0.12 mol) of zinc chloride were heated to 140 ° C. and melted. To this, 75.3 g (0.80 mol) of phenol was added, and stirring was continued at 140 ° C. for 6 hours. Thereafter, the reddish-brown reaction mixture was poured into 1.5 l of ice water, and extracted with ethyl acetate. The ethyl acetate extract was dried and then concentrated, and the obtained dark brown viscous oil was purified by column chromatography (filler: silica gel, eluent: n-hexane / ethyl acetate = 4/1). White powder (1,3-bis (4'-hydroxyphenyl) -1-propanone)

[0036]

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55 g were obtained.

To 48.5 g (0.20 mol) of 1,3-bis (4'-hydroxyphenyl) -1-propanone are added 188 g (2.0 mol) of phenol and 1 ml of thioglycolic acid, and the mixture is heated to 50 ° C. Heated. After hydrogen chloride gas was introduced into this for 7 hours, stirring was further continued at 50 ° C. for 10 hours. The dark brown reaction mixture was distilled under reduced pressure to remove excess phenol. The obtained black-brown solid was subjected to column chromatography (filler: silica gel, eluent: n-
Hexane / ethyl acetate = 3/1). As a result, 43 g of a white powder was obtained. NMR confirmed that this white powder was 1,1,1,3-tetrakis (4′-hydroxyphenyl) propane [Ic].

(7) Synthesis Example 3 Synthesis of Compound [Im] 52.8 g (0.40 mol) of glutaric acid and zinc chloride 3
2.7 g (0.24 mol) of the mixture was heated to 140 ° C. and melted. To this, 151 g (1.6 mol) of phenol was added, and stirring was continued at 140 ° C. for 6 hours. Thereafter, the reddish-brown reaction mixture was poured into 1.5 l of ice water, and extracted with ethyl acetate. The ethyl acetate extract was dried and concentrated, and the resulting black-brown viscous oil was purified by column chromatography (filler: silica gel, eluent: n-hexane / ethyl acetate = 3/1). White powder (1,5-
Bis (4'-hydroxyphenyl) -1,5-pentanedione

[0040]

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59 g were obtained.

56.9 g of this 1,5-bis (4'-hydroxyphenyl) -1,5-pentanedione (0.20 g
376 g (4.0 mol) of phenol and 2 ml of thioglycolic acid were added to the mixture, and the mixture was heated to 50 ° C. After hydrogen chloride gas was introduced into this for 8 hours, it was further added at 50 ° C. for 12 hours.
Stirring was continued for hours. The dark brown reaction mixture was distilled under reduced pressure,
Excess phenol was distilled off. The resulting black-brown solid was purified by column chromatography (filler: silica gel, eluent: n-hexane / ethyl acetate = 2/1). As a result, 56 g of a white powder was obtained. According to NMR, this white powder was 1,1,1,5,5,5-hexakis (4 ′
-Hydroxyphenyl) pentane [I-m].

(7) Preparation and Evaluation of Positive Photoresist Composition The cresol novolak resin (A) or (B) obtained in the above (1) or (2) and the cresol novolak resin obtained in the above (3) or (4) Photosensitive material a or b and additives (1) to
(6) was dissolved in 15 g of ethyl cellosolve acetate at the ratio shown in Table 2 and filtered using a 0.2 μm microfilter to prepare a photoresist composition. The 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 1.2 μm-thick resist film. Next, exposure was performed through a test chart mask using a reduction projection exposure apparatus FPA-1550 manufactured by Canon Inc., developed with a 2.38% aqueous solution of tetramethylammonium hydroxide for 1 minute, washed with water for 30 seconds, and dried.

The resist pattern on the silicon wafer thus obtained was observed with a scanning electron microscope to evaluate the resist. Table 3 shows the results.

[0045]

[Table 1]

[0046]

[Table 2]

[0047]

[Table 3]

The sensitivity was defined as the reciprocal of the exposure amount for reproducing a mask pattern of 0.70 μm, and was shown as a relative value to the sensitivity of Comparative Example 1. The residual film ratio was expressed as a percentage of the ratio of the unexposed portion before and after development. The resolving power indicates a limit resolving power at an exposure amount for reproducing a mask pattern of 0.70 μm. The heat resistance was a temperature at which the resist-patterned silicon wafer was baked in a convection oven for 30 minutes and the pattern did not deform. The shape of the resist was represented by the angle (Θ) between the resist wall surface in the cross section of the resist pattern of 0.70 μm and the plane of the silicon wafer. Regarding the developability, ○ indicates that the surface layer peeling and film residue were not observed and was good, X indicates the case where many were observed, and Δ indicates that it was slightly observed. As you can see,
The resists using the additives ( 2 ) to (3) of the present invention were excellent in sensitivity, residual film ratio, resolution, heat resistance, resist shape and developability.

[0049]

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

Continuation of the front page (56) References JP-A-4-12356 (JP, A) JP-A-4-12357 (JP, A) JP-A-5-265211 (JP, A)

Claims (1)

(57) [Claims] 1. A positive photoresist composition comprising an alkali-soluble resin, a quinonediazide compound and a compound represented by the following general formula (I). Embedded image Here, R _{1 to} R ₄ may be the same or different and may be a hydrogen atom, a hydroxyl group, a halogen atom, an alkyl group, an alkoxy group or an alkenyl group, R ₅ , R ₆ : a hydrogen atom, an alkyl group or a) c: 0 or 1, b: 0 or an integer of 1 to 4, However, when b = 0 and a = 1 , both R ₅ and R ₆
Either one it is when it is hydrogen atom and R ₅ and R ₆
Is a hydrogen atom and the other is an alkyl group having 1 to 4 carbon atoms.
Excludes cases where When b = 1 and a = 1, R ₅ and R
Except when both ₆ represent a hydrogen atom. Also, b = 2,
Table both hydrogen atom of _{R 5} and _{R 6} when a = 1, c = 0
Excluding the case.