JPS6289040A - Positive type photoresist composition - Google Patents

Abstract

PURPOSE:To improve various properties including sensitivity, resolving power and pattern shape, etc., by mixing a naphthoquinone diazide compd. which applies a specific positive type photoresist compsn. with an alkali soluble resin and using such mixture. CONSTITUTION:A naphthoquinone diazide compd. is first obtd. by bringing 1,2-naphthoquinone-2-diazide-4-sulfonyl chloride, etc. into reaction with 2,3,4,4'- tetrahydroxybenzophenon carboxylate. Such naphthoquinone diazide compd. is then mixed with the alkali soluble resin at about 5-50wt% and such mixture is used. A highly polar solvent such as methyl Cellosolve or ethyl Cellosolve or the solvent mixture composed thereof or the solvent mixture further added with arom. hydrocarbon is used for the solvent in this case. The resist compsn. prepd. in the above-mentioned manner is coated on a substrate and is then exposed to a prescribed pattern. Such resist is developed. The photoresist compsn. having the improved properties including sensitivity, resolving power and pattern shape, etc., is thus obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to positive photoresist compositions. Specifically, the present invention relates to a positive photoresist composition containing a naphthoquinone diazide compound.

[Conventional technology]

The density of integrated circuits has been increasing at an accelerating rate year by year, and we are now moving into the era of so-called ultra-LSIs with higher integration density.As a result, the requirements for IJ technology are becoming stricter year by year. .

In modern lithography processes.

In order to improve the resolution, a process was introduced in which reduced projection was performed using the original monochromatic light of low intensity, and a single wafer was divided and exposed many times. The proportion of exposure time in the overall process is increasing, as the shapes to be used are becoming more and more complex and the number of exposures is also increasing. Therefore, improving the sensitivity of the resist will greatly improve the throughput of VLSI manufacturing, and will also greatly contribute to cost performance since it will improve the throughput of processes that use extremely expensive machines such as reduced projection exposure machines. Under these circumstances, there has been a strong desire for the emergence of a nine-positive resist that maintains the high resolution characteristic of positive resists while improving sensitivity.

Tokukai Akira! No. 1/7//C discloses a positive resin containing a borac resin with a softening point of /10 to /ltr°C obtained by condensing a mixture of ortho-, meta-, and para-cresol with formaldehyde and a naphthoquinone diazide sensitizer. type photoresist compositions are described.

[The problem that the invention attempts to solve]

Conventional positive photoresists are still far from fully satisfactory in terms of sensitivity, resolution, pattern shape, etc.

That is, an object of the present invention is to provide a photoresist composition that is further excellent in sensitivity, resolution, pattern shape, etc.

[Means for solving problems]

The inventors of the present invention have carried out extensive studies and have found that the υ problem can be solved by using a naphthoquinone diazide compound that provides an excellent positive photoresist composition, and have completed the present invention.

That is, the gist of the present invention resides in a photoresist composition of 3.4(, &'-tetrahydroxybenzophenone carboxylic acid ester type).

The naphthoquinone diazide compound in the present invention is %co,
,7. +, F'-tetrahydroxybenzophenone carboxylic acid ester, /, -naphthoquinone-S-diazido-Hiroshi-sulfonyl chloride, or/, conaphthoquinone-diazide-! - It can be obtained by reacting sulfonyl chloride according to a conventional method.

Ko, J, 4'4'-tetrahydroxybenzophenone carpone ester is one...? 4'-tetrahydroxybenzophenone is partially esterified with a carboxylic acid, and specific examples of the carboxylic acid include alkyl or aryl carboxylic acids.

7, TI/ki/l/carboxylic acids include acetic acid 11 gropionic acid, hydroxyacetic acid, hydroxypropionic acid, etc., and arylcarboxes σ include:
Benzoic acid, monohydroxybenzoic acid, dihydroxybenzoic acid,
Examples include V-arg, trihydroxybutyric acid, and the like.

In the present invention, 3. A naphthoquinonediazide sulfonic acid ester compound of 'I,'I'-tetrahydroxybenzophenonecarboxylic acid ester is used as a resist composition by mixing it with a novolac resin or an alkali-soluble resin such as a vinylphenol species (fat). (Five examples of fats: tJf, phenol, 0-cresol, m-cresol, p-cresol, co-, 3-xylenol.

Yu, left - xylenol, 3. Turkylenol.

, 3. ! i'-xylenol or α-naphthol,
It is obtained by condensing a compound having a phenolic OH group such as β-naphthol with an aldehyde such as formaldehyde, acetaldehyde, or benzaldehyde. Also, vinyl phenol position (for example, fat is 1).

Use one with the following structure.

The naphthoquinonediazide compound of the present invention (2,,3,Q
, 4t'-tetrahydroxybenzophenone carboxylic acid ester naphthoquinonediazide sulfonic acid ester)
is 5 to jO weight% based on the above alkali-soluble resin.
They are used in mixed quantities, and usually they are dissolved in an appropriate solvent. The solvent is not particularly limited as long as it does not react with the photosensitive 41 and alkali-soluble resins, has sufficient solubility, and provides good coating properties, but examples include methyl cellosolve, ethyl cellosolve, butyl cellosolve, and methyl cellosolve acetate. .

Ester thread solvents such as dimethylformamide, N-
Examples include highly polar solvents such as methylpyrrolidone and dimethyl sulfoxide, a mixture of these solvents, and those to which aromatic hydrocarbons are further added.

A good resist can be obtained by applying the above-mentioned resist composition to a substrate by a known method, exposing it to light in a predetermined pattern, and developing it.

The current solution of the positive photoresist composition of the present invention includes sodium hydroxide, potassium hydroxide 1, WV sodium,
Inorganic alkalis such as sodium silicate, disodium metasilicate, aqueous ammonia, primary amines such as ethylamine and n-propylamine, diethylamine, di-n
- Tertiary amines such as propylamine, tertiary amines such as triethylamine, methyldiethylamine, tetramethylammonium hydroxide.

An aqueous solution of a quaternary amine such as trimethylhydroxyethylammonium hydroxide, or the like, or a solution prepared by adding alcohol, a surfactant, etc., can be used.

The positive irradiation-resistant resin composition of the present invention is useful not only for VLSI, but also for general IOF manufacturing, mask production a, and offset printing.

The resist iJ1 paraboloid of the present invention contains a dye and a plasticizer (1,
Additives such as adhesion promoters, development accelerators, and surfactants may be mixed.

The present invention will be explained in more detail with reference to specific examples below, but the present invention is not limited in any way by these examples.

Example/2, J, 'I, 'I'-detrahydroxybenzofuninone benzokyo ester yada/ (to L x 10-s mol), and 1,2-naphthoquinone-diazide-5
- Dissolve sulfonyl chloride J,, ly (/J x / (f' mol) in dioxane SO, add triethylamine with stirring, and continue the reaction at -5 to 30°C for S time. Cooling. Add 100 ml of water afterward to precipitate the reactants and separate them.

After Q VC/00 tri in ethanol! Koshi, U
- Separated and dried as an orange powder (decomposition point luta~i3o)
℃), 3.9 jp was obtained.

Naphthoquinonediazide compound 0 synthesized by the above method
．． 211, li+ and 1m-cresol 30% by weight, p
-Cresol qON amount%, 2. ! - Novolac synthesized from 30% xylenol and formalin, dissolved in ethyl cellosolve acetate), y, i g, filtered with a Millipore filter of θ, λμ, and applied with a positive resist α to make. this! It was spin-coated on a silicon wafer with a saponification interval of rooo^ ("102") and prebaked at 90°C for 30 minutes to obtain an on-coat. -M A -10 was used to determine the sensitivity (minimum *-yt at which the remaining film thickness is 0, expressed as the reciprocal of time).Development was performed for 20"01 minutes using NMD-3 manufactured by Tokyu Ohka A. . The resolution test was conducted using the above-mentioned mask aligner using Toppan Printing Co., Ltd.'s resolution I'px test pattern.

Further, the percentage of the film thickness after development with respect to the film thickness before development in the unexposed area is defined as the residual film thickness, and is used as a measure of the degree of film thickness after development in the unexposed area.

Furthermore, a naphthoxydiazide-based compound synthesized in the same manner as in Example 1 except that co, j, tI, 4('-tetrahydroxybenzophenonecarboxylic acid ester was changed) was evaluated in the same manner, so Table 1 is also shown. Summarize.

The method for synthesizing the borac resin used above from 30% by weight of m-cresol, 110% by weight of p-cresol, 30% by weight of M, 30% by weight of yo-xylenol, and formalin is as follows.

m-Cresol/deO,p (8 moles), 2.5-xylenol/&/i (/, λ demoles), J? % formalin rich!
, 2 J/ (J, 39 mol) and oxalic acid dihydrate 10JifI: React at 19-93°C for 5 hours with stirring.

Thereafter, the mixture was cooled to room temperature, reduced to 305w Hi, and gradually heated again to expel moisture and residual monomers. Finally, it took 3 hours to heat up to /76°C. The remaining resin was poured into a stainless steel vat and cooled. The yield is 27. Weight i average molecule tic MW in terms of polystyrene by t-gel permeation chromatography
When I asked for it, it was 4#10.

Clothes-l When the cross-sectional shape of the pattern of the above-mentioned example was observed using an electron microscope, it was found that the pattern was good with good hem-cutting.

〔Effect of the invention〕

The positive photoresist composition of the present invention has excellent physical properties such as sensitivity, resolution, pattern shape, etc., and is highly preferred in practice for use in processing highly integrated ultra-LTI.

Claims (2)

[Claims] (1) A positive photoresist composition comprising a naphthoquinonediazide sulfonic acid ester of 2,3,4,4'-tetrahydroxybenzophenonecarboxylic acid ester and an alkali-soluble resin. (2) The positive photoresist composition according to claim 1, wherein the alkali-soluble resin is a phenolic novolak resin.