JPH01291242A - Positive type photoresist composition containing novel photosensitive agent - Google Patents

Abstract

PURPOSE:To improve the resolution and the process stability of the title material, without injuring the sensitivity and the thermo-resisting property of the photoresist material by incorporating a 1,2-quinone diazide compd. composed of a specified compd. in the photoresist material. CONSTITUTION:The 1,2-quinone diazide compd. shown by formula I and an alkali soluble resin are incorporated in the photoresist material. In the formula, Ra and Rb are the same or the different with each other, and are each H, OH, 1-4 C alkyl group or halogen atom, D is 1,2-naphthoquinone diazide-4- sulfonyl group, 1,2-naphthoquinone diazide-5-sulfonyl group of 1,2-benzoquinone diazide-4-sulfonyl group, (m) and (n) are each an integer of 0-5, (m+n)>=1. The positive type photoresist composition is obtd. by dissolving the alkali soluble resin and the 1,2-quinone diazide compd. in an appropriate solvent so as to be in an amount of 20-40pts.wt. based on a solid matter contd. in the photoresist composition. Thus, the excellent performances of the photoresist material such as the sensitivity, the resolution, the thermo-resisting property and a pattern shape of the photoresist, are obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Fields] The present invention relates to an alkali-soluble resin that can be used as a resist material sensitive to radiation such as ultraviolet rays, deep ultraviolet rays, electron beams, and X-rays, and novel 1.2- The present invention relates to a positive photoresist composition comprising a quinonediazide compound and a pattern forming method.

[Prior Art] In recent years, the density and integration of semiconductor integrated circuits have progressed, and we have entered an era where the degree of integration is 4 Mbits or more, and pattern formation of submicron rules or even smaller ones has become necessary.

The positive photoresist consists of an alkali-soluble novolak resin and a 1°2-quinonediazide compound that functions as an alkali dissolution inhibitor.

In the radiation irradiated part, the 1,2-quinonediazide compound becomes ketene through carbene, reacts with moisture inside and outside the system, and indene carboxylic acid is produced, which becomes easily dissolved in an aqueous alkaline solution. On the other hand, the unirradiated area is dissolved in an alkaline developer, hardly swells, and maintains a high residual film ratio. As a result, a high resolution resist pattern is obtained. Conventional cyclized polyisoprene-based negative resists have limited resolution due to swelling of the film during development.
Recently, positive resists have been mainly used.

By the way, in order to meet increasingly stringent requirements, various improvements are being attempted in positive photoresists, and a wide range of detailed studies are being conducted on everything from resins, photosensitizers, developers, and additives. .

In particular, high sensitivity, high resolution, rectangularity of pattern profile, high dry etching resistance, high heat resistance, and process stability are strongly desired and are the goals of improvement.

[Problem to be solved by the invention] However, sensitivity and resolution, sensitivity and heat resistance, and sensitivity,
Resolution, heat resistance and process stability tend to contradict each other. For example, increasing the molecular weight of the resin increases heat resistance, but reduces sensitivity, resolution, and process stability. When copolymerization is performed to improve heat resistance, process stability decreases. Furthermore, when the amount of photosensitizer is increased, the resolution improves, but the sensitivity decreases. As described above, since there are many contradictory properties, it has been extremely difficult to achieve high performance without degrading other properties.

Furthermore, in the case of ultraviolet light as an exposure source, for example, its wavelength is shifting from g-line to i-line. Various resists that can be used with g-line or i-line are being developed, but a resist that can be used with both has not yet been developed.

[Means for Solving the Problems] Based on this background, the present inventors have conducted extensive research and have found that amide compounds containing a piperazine ring are effective. In other words, the novel compound of the present invention (
By using the 1,2-quinonediazide compound consisting of 1), resolution,
It was discovered that the photoresist has improved process stability and can be used for g-line and i-line, and has completed the present invention.

That is, general formula (I), (However, R,, R, are the same or different H, OH.

Indicates an alkyl group having 1 to 4 carbon atoms and a halogen atom.

D is a 1.2-naphthoquinonediazide-4-sulfonyl group, a 1.2-naphthoquinonediazide-5-sulfonyl group,
1.2-benzoquinonediazide-4=represents a sulfonyl group. mSn each represents an integer from 0 to 5, m and n are 1
That's all. ) A positive photoresist composition comprising a novel 1,2-quinonediazide compound represented by the following formula and an alkali-soluble resin, and a pattern forming method are provided.

In addition, examples of the alkyl group of R, , Rb in general formula (I) include methyl group, ethyl group, propyl group, butyl group, etc., and examples of the halogen include chlorine, fluorine, bromine, etc.

The novel 1゜2-quinonediazide compound represented by the general formula (1) in the present invention has the following general formula (II), (however,
R,, Rb represent the same or different H1 alkyl group having 1 to 4 carbon atoms, or a halogen atom. m1n is each 0 to 5
represents an integer/number, where m+n is 1 or more. ) of the compound represented by 1゜2-naphthoquinonediazide-4
It can be synthesized by esterifying all or part of -sulfonyl chloride, 1,2-naphthoquinonediazide-5-sulfonyl chloride, and 1,2-penzoquinone diacyto-4-sulfonyl chloride.

Although there are no particular limitations on the method for synthesizing general formula (II), it can be synthesized, for example, by the following method. It can be synthesized by reacting polyhydroxybenzoyl chloride with piperazine or by reacting polyhydroxybenzoic acid with piperazine in acetic anhydride under reflux. Thereafter, it can be purified by recrystallization or column separation.

In addition, the esterification of the general formula (n) and the sulfonyl chloride is carried out in the presence of a salt disturbance such as potassium hydroxide, sodium hydroxide, alkali carbonate, triethylamine, pyridine, etc.
It can be synthesized by reacting the required equivalent amount of sulfonyl chloride.

As the alkali-soluble resin of the present invention, 1.2 of the present invention
- There is no particular limitation as long as the resin dissolves uniformly in the quinonediazide compound. For example, the following may be mentioned. Examples include novolac resins such as phenol and cresol, polyvinylphenol or copolymers thereof, and polymers containing carbonic acid such as styrene-maleic anhydride copolymers or half esters thereof. Particularly preferred is a novolac resin, which can be synthesized by the following method. The corresponding monomer and aldehydes such as formaldehyde, paraformaldehyde, and acetaldehyde are combined with phosphoric acid, oxalic acid,
It can be synthesized by polycondensation according to a known method in the presence of an acidic catalyst such as acetic acid, hydrochloric acid, nitric acid, sulfuric acid, or Lewis acid. The weight average molecular weight of the resin is 2000 to 30000
(polystyrene equivalent) is preferable. Within this range, sensitivity, resolution, heat resistance, and process stability are excellent.

Further, as monomers used in the novolac resin that can be used in the present invention, for example, the following phenols can be used alone or in a mixture of two or more. Phenols include phenol, 0-cresol, m-cresol, p-cresol, 0-ethylphenol, m-ethylphenol, p-ethylphenol,
0-n-butylphenol, m-n-butylphenol, p-n-butylphenol, o-t-butylphenol, m-t-butylphenol, p-t-butylphenol, 0-methoxyphenol, m-methquinphenol, p-methoxy Phenol, 0-fluorophenol, m-fluorophenol, p-fluorophenol,
0-chlorophenol, m-chlorophenol, p-chlorophenol)Iy, a-nitrophenol, m-nitrophenol, p-nitrophenol, 2,4-xylenol, 2,5-xylenol, 3,4- Examples include xylenol, 3,5-xylenol, and the like. Furthermore, if necessary, the hydroxyl group of the phenol may be replaced with a sulfonic acid or a carbonic acid ester. Esterification components include alkyl groups such as methyl, ethyl, and propyl, or phenyl, l-lyl, benzoic acid, naphthyl,
Examples include aromatic rings such as benzyl, cumyl, and phenethyl.

The amount of the novel 1,2-quinonediazide compound of the present invention is preferably 20 to 50 parts by weight per 100 parts by weight of the alkali-soluble resin. Within this range, a sufficient difference in solubility in the developer between exposed and unexposed areas can be obtained, and a pattern with excellent sensitivity and resolution can be obtained.

The positive photoresist composition of the present invention contains an alkali-soluble resin and a 1,2-quinonediazide compound in a solid fraction of 2.
It is obtained by dissolving it in an appropriate solvent to a concentration of 0 to 40 parts by weight. Examples of the solvent include ethylene glycol monoalkyl ether and its acetates, propylene glycol monoalkyl ether and its acetates,
Examples include diethylene glycol dialkyl ethers, ketones such as methyl ethyl ketone and cyclohexanone, acetate esters such as ethyl acetate and butyl acetate, aromatic hydrocarbons such as toluene and xylene, dimethylacetamide and dimethylformamide. These solvents can be used alone or in combination of two or more. Also,
Photosensitizers other than those of the present invention may also be used in combination. Furthermore, if necessary, nonionic, fluorine, silicone, etc. surfactants can be added to improve coating properties, and other sensitizers, colorants, stabilizers, etc. Certain additives may also be included.

[Function] The positive photoresist composition comprising the alkali-soluble resin of the present invention and the novel 1,2-quinonediazide compound has the following properties:
It can be used to form resist patterns using ultraviolet rays, deep ultraviolet rays, electron beams, X-rays, etc., and has excellent sensitivity, resolution, heat resistance, and process stability.

There are no particular limitations on how to use the positive photoresist composition of the present invention to form a resist pattern using radiation, and the method can be carried out according to a conventional method.

For example, the positive photoresist solution of the present invention is prepared by dissolving an alkali-soluble resin, a 1,2-quinonediazide compound, and additives in a solvent, and filtering the solution through a 0.2 μm filter. A resist film is obtained by spin-coding a resist solution onto a substrate such as a silicon wafer and pre-baking it. Thereafter, a resist pattern can be formed by performing exposure using a reduction projection exposure device, an electron beam exposure device, or the like, and developing.

Examples of developing solutions include: tetramethylammonium hydroxide, quaternary ammonium salts such as choline, organic alkali aqueous solutions such as amines, or inorganic alkali aqueous solutions such as thorium hydroxide, potassium hydroxide, sodium carbonate, and aqueous ammonia. can be used. Other methods such as coating, pre-baking, exposure, and development can be carried out by conventional methods.

[Examples] Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto.

Synthesis Example 1 3,4-dihydroxybenzoyl chloride 9. i5g, piperazine 2.51g
was dissolved in 250 mal of chloroform, and 50 d of a chloroform solution of 5.90 g of triethylamine was added dropwise at room temperature while stirring over 30 minutes. Thereafter, the reaction continued for 200 hours.

After the reaction, the reaction solution was sequentially treated with saturated brine, IN aqueous hydrochloric acid solution,
It was washed with saturated saline and dried with anhydrous sodium sulfate. Thereafter, the mixture was filtered and the solvent was removed using an evaporator to obtain N,N--bis(3°4-dihydroxybenzoyl)piperazine.

Purification of the compound was performed by column separation. Yield is 3.1
It was g. Purity determined by reverse phase chromatography was 97.5%.

Elemental analysis values are C60.7%, H4.5%, H8.1%
showed that.

Synthesis Example 2 N, N--bis(3,
2.5 g of 4-dihydroxybenzoyl)piperazine and 5.64' g of 1,2-naphthoquinonediazide-5-sulfonyl chloride were dissolved in 50 g of dioxane, and a dioxane solution of 2.4 g of triethylamine was added with stirring at room temperature. It was added dropwise over 20 minutes. Thereafter, the reaction was continued for 3 hours. After the reaction, the triethyl amyletate was filtered, and the filtrate was poured into a large amount of ion-exchanged water to precipitate the 1°2-quinonediazide compound. This was filtered, washed successively with ion-exchanged water and ethanol, and then dried to obtain a powder. The yield was 6.9g.

Elemental analysis values are C54.9%, H2.5%, N10.4
%, N9.0%.

Synthesis Example 3 According to Synthesis Examples 1 and 2, 1°2-naphthoquinonediazide-5-sulfonic acid ester of N,N--bis(3°5-dihydroxybenzoyl)piperazine (3 hydroxyl groups on average are esterified) was obtained. Ta.

Synthesis Example 4 30 g of 0-cresol, m
- 55 g of cresol, 45 g of p-cresol, and 1.75 g of oxalic acid dihydrate were added. Under a nitrogen atmosphere, the mixture was immersed in an oil bath without stirring, and the temperature was raised to an internal temperature of 100°C. While maintaining the internal temperature at 100° C., 86 g of a 35% aqueous formalin solution was added dropwise over 90 minutes. Thereafter, the reaction was continued for 10 minutes to synthesize a novolac resin. After the reaction, 112 g of resin powder was obtained by repeating dissolution and precipitation and drying.

The weight average molecular weight of novolak resin is G P C411
As a result of one constant, it was 4/50 in terms of polystyrene.

Further, the degree of dispersion (weight average molecular weight/number average molecular weight) is 4.
It was 73.

Example 1 1,2-quinonediazide compound obtained in Synthesis Example 2 2.25
．． g and 8 g of the novolac resin obtained in Synthesis Example 4 were dissolved in 24 g of ethylene glycol monoethyl ether acetate, and filtered through a 0.2 μm membrane filter to obtain a resist solution.

The resist solution was spin-coated onto a 4-inch silicon wafer using a spinner, and prebaked at 90°C for 30 minutes in a circulating constant temperature bath to form a 1.5 μm thick resist!・A film was obtained. Next, a reduction projection exposure device (manufactured by GCA, DSW-63
00A, N, A, -0, 35) was used to expose through the reticle.

Immersion development was performed at 25° C. for 11 minutes using a 2.30 weight aqueous solution of tetramethylammonium hydroxide as a developer.

The exposure dose for one-to-one resolution of 1.0 μm lines/spaces was 1.45 mJ/cm2.

Regarding resolution, it was possible to resolve 0.7 μm line/space, and the pattern was rectangular.

Next, resist patterns with 2 μm lines/spaces of 140, 145, 150, 155°1.60, 1
Baking was performed at each temperature of 65,170°C for 30 minutes in a constant temperature bath, and the heat resistance was evaluated based on the presence or absence of pattern deformation. As a result, the heat resistance was 155°C.

Example 2 As a reduction projection exposure apparatus, DSW'-6300A is
An exposure test was carried out in accordance with Example 1, except that a one-line reduction projection exposure apparatus having a lens with A, = 0.42 was used.

As a result, the exposure dose for resolving 1.0 μm lines/spaces on a one-to-one basis was 157 mJ/cm′. Regarding the resolution, one image of 0.5 μm line/space could be resolved, and the pattern was rectangular.

Example 3 Using the 1,2-quinonediazide compound obtained in Beach Formation Example 3, an exposure test and a heat resistance test were conducted according to Example 1.

As a result, the exposure dose for resolving 1.0 μm line/space one-to-one was 140 mJ/cm2.

Regarding the resolution, a 0.7 μm line/space could be resolved, and the pattern was rectangular.

Heat resistance was 155°C.

[Effects of the Invention] The positive photoresist composition comprising the alkali-soluble resin of the present invention and the novel 1,2-quinonediazide compound has the following properties:
The 1,2-quinonediazide compound contains a piperazine ring and consists of a carboxylic acid amide bond, has excellent sensitivity, resolution, heat resistance, and pattern shape, and exhibits good performance against both g-line and i-line light sources. Therefore, it is suitable for manufacturing semiconductor integrated circuit elements such as VLSI.

Claims (2)

[Claims] (1) General formula (I), ▲Mathematical formula, chemical formula, table, etc.▼(I) (However, R_a and R_b are the same or different H, OH
, represents an alkyl group having 1 to 4 carbon atoms or a halogen atom:
D represents a 1,2-naphthoquinonediazide-4-sulfonyl group, a 1,2-naphthoquinonediazide-5-sulfonyl group, or a 1,2-benzoquinonediazide-4-sulfonyl group; m and n are each an integer of 0 to 5; and m+n
is 1 or more) and an alkali-soluble resin. (2) A pattern forming method using the positive photoresist composition according to claim 1.