JPH03210563A - Positive type photoresist composition - Google Patents

Abstract

PURPOSE:To form patterns having excellent heat resistance and image contrast and to obviate the generation of scum after development by compounding a specific compd. with a compsn. consisting of an alkaline-soluble novolak resin having a specific dissolving rate and a quinonediazide group-contg. compd. CONSTITUTION:This compsn. is formed by incorporating the alkaline-soluble novolak resin having the dissolving rate in an aq. soln. of 8% tetramethyl ammonium hydroxide at 23 deg.C within a 50 to 1,000Angstrom /sec, the quinonediazide group- contg. compd. and alpha,alpha',alpha''-tris(4-hydroxyphenyl)-1, 3, 5-triisopropyl benzene into the compsn. The resist patterns having the excellent heat resistance and image contrast are formed in this way. The positive type photoresist compsn. which does not generate the scum in thus obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides a novel positive photoresist composition, more specifically, a resist pattern which can form a resist pattern particularly excellent in heat resistance and image contrast, and which does not generate scum. The present invention relates to a positive photoresist composition that has the following characteristics and is suitably used for manufacturing semiconductor devices.

Conventional technology Conventionally, in the manufacturing process of semiconductor devices such as ICs and LSIs, a photoresist composition is formed on a silicon wafer as microfabrication using a photoetching method, and a mask with a semiconductor device pattern drawn thereon is used. A method is used in which a pattern is transferred by ultraviolet irradiation or the like, and then the silicon wafer is etched using the resulting resist pattern as a protective film. The photoresist backing material used in this method includes an alkali-soluble resin for film formation,
It is known that positive photoresist compositions in which a photosensitive component consisting of a quinonediazide group-containing compound is combined are suitable.

Incidentally, the degree of integration of semiconductor devices has increased rapidly in recent years, and in the manufacture of ultra-LSIs, processing precision of ultra-fine patterns of 1.0 micrometers or less is required, and dry etching is becoming more and more popular. As for the desired properties of the positive photoresist composition used, it is desired that a resist pattern with excellent heat resistance and image contrast can be formed, and that no scum will be generated after development.

However, conventional positive photoresist compositions do not have sufficient heat resistance, have a low residual film rate of resist patterns formed by development, and have difficulty obtaining resist patterns with excellent image contrast. There were drawbacks.

Furthermore, it is known that the use of high molecular weight novolak resins is effective in improving heat resistance.
If a high molecular weight novolak resin is used, a problem arises in that the sensitivity tends to decrease, and it cannot be said to be practical. Thus, the reality is that no positive photoresist composition has been found that fully satisfies all of the above-mentioned demands.

Problems to be Solved by the Invention The present invention overcomes the drawbacks of such conventional positive photoresist compositions, can form a resist pattern with excellent heat resistance and image contrast, and is a positive photoresist composition that does not generate scum. This was made for the purpose of providing a photoresist composition.

Means for Solving the Problems As a result of intensive research to develop a positive photoresist composition having the above-mentioned preferable properties, the present inventors have developed an alkali-soluble novolac resin having a specific dissolution rate as a film-forming component. and a quinonediazide group-containing compound as a photosensitive component, a, a', σ"-
Tris(4-hydroxyphenyl)-1,3,5-1-
It was discovered that the objective could be achieved by blending lyisopropylbenzene, and the present invention was completed based on this knowledge.

That is, the present invention provides (A) an alkali-soluble novolac resin having a dissolution rate in an 8 wt. (C) A positive photoresist composition containing a,σ,α-tris(4-hydroxyphenyl)-1,3,5-)IJ isopropylbenzene.

The present invention will be explained in detail below.

In the composition of the present invention, the alkali-soluble novolac resin used as component (A) is 8% by weight at a temperature of 23°C.
Dissolution rate in tetramethylammonium hydroxide aqueous solution is 50 to 1000 people/sec, preferably 100 to 100
It is necessary to be in the range of 400 A/sec. If the dissolution rate is less than 50 people/second, the object of the present invention cannot be fully achieved, and if it exceeds 1,000 people/second, it tends to be difficult to obtain a resist pattern with excellent image contrast. The above dissolution rate is determined by dissolving the alkali-soluble novolak resin in an appropriate solvent to prepare a solution, applying this solution onto a substrate, drying it at 110°C for 90 seconds, and applying it to a 1.0μ thick layer. Form a resin film, then
This is immersed in an 8% by weight tetramethylammonium hydroxide aqueous solution at a temperature of 23° C., left to stand, taken out and washed with water to determine the amount of decrease in film thickness, which can be calculated from this value.

Such alkali-soluble novolac resins are produced by condensing phenols such as phenol, cresol, xylenol, and aldehydes such as formaldehyde in the presence of an acidic catalyst. It can be easily obtained by fractionating the novolak resin obtained.

In general, synthetic resins are not chemically pure substances, but are mixtures of molecules with various molecular weights, compositions, and structures, and have multimolecular properties. By removing the low molecular weight region using a fractionation treatment method, an alkali-soluble novolac resin having a desired dissolution rate can be obtained. In addition, the dissolution rate of alkali-soluble novolak resin that is not subjected to such fractionation treatment is usually in the range of 2500 to 5000 A/sec, and if it is as it is, the (A
) cannot be used as a component.

In the present invention, a quinonediazide group-containing compound is used as the photosensitive component (B).

Examples of this quinonediazide group-containing compound include lf2
．． 3.4-trihydroxybenzophenone, 2.3.4
．． Preferred examples include completely esterified products and partially esterified products of polyhydroxybenzophenone such as 4'-tetrahydroxybenzophenone and naphthoquinone-1,2-diazide-5-sulfonic acid or naphthoquinone-1,2-diazide-4-sulfonic acid. be able to. In addition, other quinonediazide group-containing compounds, such as sulfonyl chloride such as orthobenzoquinonediazide, orthonaphthoquinonediazide, orthoanthraquinonediazide, and compounds having hydroxyl or amino groups, such as phenol, p-
Methoxyphenol, dimethylphenol, hydroxyphenol, bisphenol A1 naphthol, pyrocatechol, pyrogallol, pyrogallol monomethyl ether, pyrogallol-1,3-dimethylfur, gallic acid, esterified or etherified gallic acid with some hydroxyl groups retained, aniline , p-aminodiphenylamine, etc. can also be used as photosensitive components.

The composition of the present invention may contain one type of the above-mentioned quinonediazide group-containing compound as the photosensitive component,
Two or more types may be contained.

These photosensitive components can be prepared, for example, by combining the polyhydroxybenzophenone with naphthoquinone-1,2-diazide-5-sulfonyl chloride or naphthoquinone-1,2-diazide-4-sulfonyl chloride in a suitable solvent such as dioxane. It can be produced by condensation in the presence of an alkali such as ethanolamine, alkali carbonate or alkali hydrogencarbonate, and complete or partial esterification.

In the composition of the present invention, as component (C), σ, ff
, ff#-tris(4-hydroxyphenyl)-1
, 3,5-triisopropylbenzene.

a, a, a”-tris(4-hydroxyphenyl)
-1,3,5-Triisopropylbenzene is known as a raw material and modifier for polycarbonate, polyester, epoxy resin, polysulfone, etc., and can also be obtained by condensing aldehyde with a mixture of this product and phenols. A positive photoresist composition with good resolution and heat resistance using an alkali-soluble resin is also known (Japanese Patent Laid-Open No. 63-261250). However, 1mt
, a', a'-) lis(4-hydroxyphenyl)-1
, 3,5-) It has not been known so far that it is effective to add lyisopropylbenzene itself to a photoresist composition.

This a, a, g''-)lis(4-hydroxyphenyl)-1,3,5-triisopropylbenzene has an excellent sensitizing effect, promotes dissolution of exposed areas during development, and conversely Because it has the effect of suppressing the dissolution of the photoresist, it has excellent dissolution selectivity with respect to the developing solution, and can form a resist pattern with excellent image contrast.Also, it is possible to improve the sensitivity with a small amount of compounding, so it is suitable for positive photoresist compositions. By combining the component (A) with an alkali-soluble novolac type resin having a relatively high weight average molecular weight without reducing the heat resistance of the product,
A positive photoresist composition with improved heat resistance can be provided.

In the composition of the present invention, the alkali-soluble novolak resin as the component (A) is usually used in an amount of 5 to 200 parts by weight, preferably 10 to 60 parts by weight, per 10 parts by weight of the quinonediazide group-containing compound as the component (B). Used in range. If the amount of this alkali-soluble novolac resin is too large, the image fidelity will be poor and the transferability will be lowered, and if it is too small, the homogeneity of the resist film will be poor and the resolution will tend to be reduced.

In addition, the σ,a,t-tris(4-hydroxyphenyl)-1,3,5-)liisoprobylbenzene of component (C) has a total amount of 100% of the alkali-soluble novolac resin and the quinonediazide group-containing compound. Per part by weight, usually 0.
It is used in an amount of 1 to 30 parts by weight, preferably 0.5 to 25 parts by weight. If this amount is less than 0.1 parts by weight, a resist pattern with excellent image contrast cannot be obtained, and if it exceeds 30 parts by weight, no improvement in effect is seen in relation to the amount, and it is rather unfavorable that it becomes uneconomical.

The composition of the present invention comprises the alkali-soluble novolac resin, the quinonediazide group-containing compound, and α,aa#-tris(
4-hydroxyphenyl)-1,3,5-triisopropylbenzene is preferably dissolved in a suitable solvent and used in the form of a solution.

Examples of such solvents include ketones such as acetone, methyl ethyl ketone, cyclohexane, and methyl isoamyl ketone; monomethyl ether, monoethyl ether, monopropyl ether, and motubutyl ether of ethylene glycol, ethylene glycol monoacetate, diethylene glycol, or diethylene glycol monoacetate; Or polyhydric alcohols such as monophenyl ether, cyclic ethers such as its derivatives nidioxane, and esters such as ethyl lactate, methyl acetate, ethyl acetate, and butyl acetate. These may be used alone or in combination of two or more.

The compositions of the present invention may further contain compatible additives, such as additional resins, plasticizers, stabilizers, to improve the performance of the resist film, etc., or to make the developed image more visible. It is possible to add and contain commonly used coloring agents and sensitizers to further improve the sensitizing effect.

One example of a preferred method of using the composition of the present invention is as follows:
First, on a support such as a silicon wafer, alkali-soluble novolak resin as component (A), quinonediazide group-containing compound as component (B), and a, α, a-
A solution of tris(4-hydroxyphenyl)-1,3,5-)liisobrobylbenzene dissolved in a suitable solvent as mentioned above is applied with a spinner and dried to form a photosensitive layer. Exposure is performed using a light source that emits ultraviolet rays, such as a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, an arc lamp, a xenon lamp, etc. through a required mask pattern, or irradiation is performed while scanning an electron beam.

Next, by using a developer, for example, a weakly alkaline aqueous solution such as a 1-10% by weight tetramethylammonium hydroxide aqueous solution, to dissolve and remove the portions made solubilized by exposure, an image faithful to the mask pattern can be obtained. can.

Effects of the Invention According to the present invention, an alkali-soluble novolak resin having a specific dissolution rate as a film-forming component, a quinonediazide group-containing compound as a photosensitive component, and Zaraani a, α,
σ“-tris(4-hydroxyphenyl)-1,3,5
- By combining with triisopropylbenzene, a resist pattern with extremely excellent heat resistance and image contrast can be formed, and a practical positive photoresist composition with excellent characteristics such as no scum remaining after development is provided. can do.

The positive photoresist composition of the present invention is suitably used, for example, in the production of semiconductor devices, where fine processing is progressing.

Examples Next, the present invention will be explained in more detail with reference to examples.
The present invention is not limited in any way by these examples. The dissolution rate of the alkali-soluble novolac resin in the examples was determined by dissolving the obtained alkali-soluble novolac resin in ethylene glycol monoethyl ether acetate, applying the solution on the substrate, and drying it at 110°C for 90 seconds. After forming a 1.0 μ thick machine fat film, 8
It was determined from the amount of decrease in film thickness after being left standing and immersed in a wt % tetramethylammonium hydroxide aqueous solution (23° C.) and then washed with water.

Incidentally, the physical properties of the compositions obtained in each case were measured by the following method.

(1) Apply a sensitivity sample to a silicon wafer using a spinner,
Dry on a hot plate at 110℃ for 90 seconds to obtain a film thickness of 1.
．． A resist film of 371m+ was obtained. This film was coated with a reduction projection exposure device N5R-150504D (manufactured by Kon Co., Ltd.).
．． After exposure at intervals of 1 second to 0.02 seconds, the
The sensitivity was defined as the appropriate exposure time (minimum exposure time required for buttering) after developing for 30 minutes, washing with water for 30 seconds, and drying.

(2) Remaining film rate in unexposed areas The film thicknesses of unexposed areas before and after development in the sensitivity measurement described above were measured, and the residual film rate was determined from the difference.

(3) Heat resistance The resist pattern of the silicon wafer obtained as described above was baked on a hot plate for 5 minutes at each temperature of 120°C, 130°C, 140°C, and 150°C, and whether or not the pattern was deformed. The heat resistance was evaluated using the following criteria.

O: No deformation Items that could not be confirmed were ignored.

*Example 1 m-cresol and p-cresol in a weight ratio of 40:
Cresol novolac resin (weight average molecular weight 4000, dissolution rate 40
00 A/sec) 1509 was dissolved in 850 t of methanol, 500 g of pure water was added, and the mixture was stirred for 1 hour for fractionation to obtain a cresol novolac resin fractionated as a precipitate. This one has a weight average molecular weight of 9000
The dissolution rate was 250 A/sec.

Next, 2,3,4,4'-tetrahydroxybenzophenone 9.89 (0.04 mol) and 7toquinone-1.
2-Diazido-5-sulfonyl chloride 45.6g (0
, 17 mol) was dissolved in a mixture of dioxane 2409 and N-methylpyrrolidone 37 g, and a mixture of 70 g of triethanolamine and 210 g of dioxane was added thereto with thorough stirring, and the mixture was further stirred for 30 minutes to 1 hour. Thereafter, this was filtered, and a dilute hydrochloric acid solution prepared by diluting 35% by weight hydrochloric acid 259 with ion-exchanged water 10009 was added to the obtained filtrate to precipitate the reactant, and the obtained precipitate was thoroughly washed with ion-exchanged water. Then, drain the water well and dry it.
A photosensitive component was prepared.

Next, 20 g of the cresol novolak resin obtained by the above-mentioned fractionation treatment, 5 g of the photosensitive component, and 2 g of a,aa''-tris(4-hydroxyphenyl)-1,3,5-triinpropylbenzene were mixed with ethylene glycol monomer. After dissolving in 75 g of ethyl ether acetate, this was filtered to prepare a positive cleft photoresist composition.The physical properties of this composition are shown in the table.

Example 2 m-cresol and p-cresol in a weight ratio of 35:
Talesol novolac resin (weight average molecular weight 3000, dissolution rate 27
00 A/sec) 1509 was dissolved in methanol 8509, 500 g of pure water was added, and the mixture was stirred for 1 hour for fractionation to obtain Talesol novolac resin fractionated as a precipitate. This one has a weight average molecular weight of 5500
The dissolution rate was 300 A/sec. A positive photoresist composition was prepared in the same manner as in Example 1 except that the Talesol novolak resin thus obtained was used.

The physical properties of this product are shown in the table.

Example 3 m-cresol and p-cresol in a weight ratio of 50:5
Cresol novolac resin (weight average molecular weight 10,000, dissolution rate 300
After dissolving 150 g of 0 A/sec) in 850 g of methanol, 500 g of pure water was added and the mixture was stirred for 1 hour for fractionation treatment to obtain a cresol novolac resin fractionated as a precipitate. This one has a weight average molecular weight of 13,000
The dissolution rate was 350λ/sec. A positive photoresist composition was prepared in the same manner as in Example 1 except that the cresol novolak resin thus obtained was used.

The physical properties of this product are shown in the table.

Comparative Example A positive photoresist composition was prepared in the same manner as in Example 1, except that a cresol novolac resin that had not been subjected to fractionation treatment was used. The physical properties of this product are shown in the table.

Claims (1)

[Claims] 1(A) Dissolution rate in 8% by weight tetramethylammonium hydroxide aqueous solution at 23°C is 50-100
an alkali-soluble novolac resin in the range of 0 Å/sec;
(B) Quinonediazide group-containing compound and (C) α, α′
, α″-tris(4-hydroxyphenyl)-1,3,
A positive photoresist composition containing 5-triisopropylbenzene.