JPH01291243A - Positive type photoresist material - Google Patents

Abstract

PURPOSE:To make possible the high resolution and process stability of the title material, without injuring the high sensitivity and thermo-resisting property, especially the pattern profile of the photoresist material by incorporating a 1,2-quinone diazide compd. having a compd. composed of a specified phenolic compd., as a carrier, in the photoresist material. CONSTITUTION:The 1,2-quinone diazide compd. is composed of the phenolic compd. shown by formula I. In the formula, A1-A6 are each hydrogen atom, 1-4 C alkyl, 1-4 C alkoxy group, halogen atom or OD group, and are three or more of the OD groups. (wherein D is hydrogen atom, 1,2-naphthoquinone diazide-4-sulfonyl group or 1,2-naphthoquinone diazide-5-sulfonyl group, etc.), R1-R4 are each hydrogen atom or 1-4 C alkyl group, X is a single bond, -CO-, -COO-, -S-, -SO2- or -(CH2)n- group, etc., (n) is 1-11. Thus, the excellent performances such as the sensitivity, the resolution, the thermoresisting property and the pattern shape of the photoresist material are obtd.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention provides an alkali-soluble resin and 1,2-quinonediazide which can be used as a resist material sensitive to radiation such as ultraviolet rays, deep ultraviolet rays, electron beams, and X-rays. The present invention relates to a positive photoresist material made of a 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 the era of 4 Mbits or more of integration, and pattern formation of submicron rules and even smaller ones has become necessary.

The positive photoresist composition is alkali-soluble, and functions as a borac resin and an alkali dissolution inhibitor.
- a quinonediazide compound.

In the radiation irradiated part, the 1,2-quinonediazide compound becomes ketene via carbene, reacts with moisture inside and outside the system to produce indene carboxylic acid, and becomes easily dissolved in the alkaline aqueous 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 Rika polyisoprene-based negative resists have limited resolution due to swelling of the film during development, and positive resists have recently 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.

Additionally, various improvements have been made to the equipment.
In the case of reduction projection exposure systems, the current focus of research and development is to improve the performance of lenses and shorten the wavelength of exposure sources.

[Problems to be Solved by the Invention] However, in positive photoresists, sensitivity and resolution, sensitivity and heat resistance, and sensitivity, resolution, heat resistance, and process stability tend to be contradictory.

For example, increasing the molecular weight of resin increases heat resistance, but
Decreases 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 characteristics, it has been extremely difficult to achieve high performance without degrading other characteristics.

Furthermore, in the case of ultraviolet light as an exposure source, for example, its wavelength is shifting from g-line to i-line. When a conventional g-line resist is exposed using an i-line reduction projection exposure apparatus, the pattern profile deteriorates significantly, which leads to a decrease in resolution.

In addition, various resists that can be used for either the g-line or the i-line are being developed, but a resist that can be used for both light sources, as desired by users, has not yet been developed.

[Means for Solving the Problem] As a result of extensive research based on the above background, the present inventors have developed a compound consisting of the phenolic compound (I) of the present invention.
In other words, by using a 1,2-quinonediazide compound whose carrier is a compound in which R1-R4 does not contain a hydroxyl group, it has high sensitivity, high heat resistance, and especially high resolution and high process stability without impairing the pattern profile. death,
Moreover, they discovered that the photoresist can be used for either g-line or i-line light sources, and have completed the present invention.

That is, in a positive photoresist material consisting of an alkali-soluble resin and a 1,2-quinonediazide compound, 1,
The 2-quinonediazide compound has the general formula (1), (wherein A1, A2, A1, A4, A6, A6 are hydrogen,
Indicates an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a halogen atom, OD, and at least 3 or more O
It is D. R1, R2, R3, R4 are hydrogen, carbon number 1-
4 shows the alkyl group. D may be the same or different and represents hydrogen, a 1,2-naphthoquinonediazide-4-sulfonyl group, a 1,2-naphthoquinonediazide-5-sulfonyl group, a 1,2-benzoquinonediazide-4-sulfonyl group, One is quinonediazide.

X is a single bond, -CO-1-COO-1-S-1-SO2
-1-(CH2). -1-C(CH3)2-1-C(C
F3) 2-1-NH-1-(Co)NH(CH2). Indicates NH(Co)-1,
n represents 1-11. ) 2, 2-16.
The object of the present invention is to provide a positive photoresist material and a pattern forming method characterized by comprising a phenolic compound in which the substituent at the 6' position is hydrogen and/or a lower alkyl group.

In addition, A1, A2, A3, A, l in general formula (I)
, A5, A6, the alkyl group includes methyl group, ethyl group, propyl group, butyl group, etc., the alkoxy group includes methoxy group, ethoxy group, propoxy group, butoxy group, etc., and the halogen includes chlorine, fluorine, etc. , bromine, etc.

Examples of the alkyl groups for R, R2, R3, and R4 include methyl, ethyl, propyl, and butyl groups.

The method for synthesizing the 1,2-quinonediazide compound represented by the general formula (I) in the present invention is not particularly limited, but it can be synthesized, for example, by the following method.

The following general formula (n), (where B1, B2, B3, B4, B,, B6 represent a hydroxyl group, hydrogen, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a halogen atom, Three or more represent hydroxyl groups. R1, R2, R3, and R4 are hydrogen and have 1 to 4 carbon atoms.
represents an alkyl group.

X is a single bond, -CO-, -COO-, -S-, -SO2
-, - (CH2). -, -NH-.

C(CH3)2-, C(CF3)2-, - (Co)
NH (CH2) nNH (Co)−+, n
represents 1 to 11. ), 1,2-naphthoquinonediazide-4-sulfonyl chloride, 1,2-naphthoquinonediazide-5-sulfonyl chloride, 1.

It can be synthesized by esterifying all or a portion of 2-benzoquinonediazide-4-sulfonyl chloride in the presence of a base such as potassium hydroxide, thorium hydroxide, alkali carbonate, triethylamine, or pyridine.

The alkali-soluble resin of the present invention includes 1 and 2 of the present invention.
- There is no particular limitation as long as the resin dissolves uniformly in the quinonediazide compound, but examples include the following. Examples include novolak resins such as phenol and cresol, polyvinylphenol or copolymers thereof, and polymers containing carboxylic acids such as styrene-maleic anhydride copolymers or half esters thereof. Particularly preferred is a novolac resin, which can be synthesized by the following method.

Synthesized by polycondensing the corresponding monomer and aldehydes such as formaldehyde, paraformaldehyde, and acetaldehyde in the presence of an acidic catalyst such as formic acid, oxalic acid, acetic acid, hydrochloric acid, nitric acid, sulfuric acid, and Lewis acid according to a known method. can. The weight average molecular weight of the resin is 2000 to 3000
0 (polystyrene equivalent) or preferably. Within this range, sensitivity, resolution, heat resistance, and process stability are excellent.

Further, as monomers used in the novolak 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,
o-n-butylphenol, m-n-butylphenol, p-n-butylphenol, o-t-butylphenol, m-t-butylphenol, p-t-butylphenol, 0-methoxyphenol, m-methoxyphenol, p-methoxyphenol , 0-fluorophenol, m-fluorophenol, p-fluorophenol,
0-chlorophenol, m-chlorophenol, p-chlorophenol, 0-nitrophenol, m-nitrophenol, p-nitrophenol, 2.4-xylenol, 2,5-xylenol, 3.4-xylenol, 3
．． Examples include 5-xylenol. Furthermore, if necessary, the hydroxyl group of the phenol may be substituted with a sulfonic acid or a carboxylic acid ester. Examples of the esterification component include alkyl groups such as methyl, ethyl, and propyl, and aromatic rings such as phenyl, tolyl, benzoate/caftyl, benzyl, cumyl, and phenethyl.

The 1,2-quinonediazide compound of the present invention is preferably used in an amount of 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 material of the present invention contains an alkali-soluble resin and a 1,2-quinonediazide compound at a solid content of 20%.
It is obtained by dissolving it in an appropriate solvent so that the amount becomes 40 parts by weight. Examples of the solvent include ethylene glycol monoalkyl ether and its acetates, propylene glycol monoalkyl ether and its acetates, diethylene glycol dialkyl ethers, ketones such as methyl ethyl ketone and cyclohexanone, acetic acid esters such as ethyl acetate and butyl acetate, Examples include aromatic hydrocarbons such as toluene and xylene, dimethylacetamide, and dimethylformamide.

These solvents can be used alone or in combination of two or more. Moreover, other photosensitizers other than those of the present invention can also be used in combination. Furthermore, if necessary, in order to improve coating properties, nonionic, fluorine-based, silicone-based surfactants, etc. can be added, and other sensitizers, colorants,
Compatible additives such as stabilizers can also be blended.

[Function] The positive photoresist material comprising the alkali-soluble resin and 1,2-quinonediazide compound of the present invention can be used for resist pattern formation using ultraviolet rays, deep ultraviolet rays, electron beams, X-rays, etc., and has excellent sensitivity, Excellent resolution, heat resistance and process stability.

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

As a developer, for example, an organic alkali aqueous solution such as a quaternary ammonium salt such as tetramethylammonium hydroxide, choline, amines, or an inorganic alkali aqueous solution such as sodium hydroxide, potassium hydroxide, sodium carbonate, or aqueous ammonia is used. 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 In a 300 ml 3 flask, 50 g of gallic acid,
0g, acetic anhydride 108.5g and sodium acetate 0.4
g was added and the reaction mixture was stirred at reflux for 4 hours at 140-150°C. After cooling to room temperature, ethyl acetate was added to the reaction mixture, and acetic acid produced during the reaction was removed by washing with water. After drying the separated organic layer over anhydrous sodium sulfate, the solvent was distilled off using an evaporator, and the product was dried under vacuum to obtain 62.6 g of colorless powder crystals of 3,4.5-triacetoxybenzoic acid. Ta. Purity by reverse phase chromatography was 97.6%. Elemental analysis value is C52.3
%, ■4.3%.

Next, in a 300 m1 3 flask, the 3 obtained above,
4.5-Triacetoxybenzoic acid20. After adding 200 ml of Og1 chloroform and 947 g of thionyl chloride and refluxing the reaction mixture for 2-3 hours, the solvent and excess thionyl chloride were distilled off under reduced pressure. The product was dried in vacuo in the presence of phosphorus pentoxide to obtain 19.2 g of colorless crystalline 3,4.5-1-lyacetoxybenzoic acid chloride. Elemental analysis values were C49.2%, H3.9%, and C111.7%.

Next, 15.0 g of 3,4°5-triacetoxybenzoic acid chloride obtained above and 10 g of benzene were mixed in a 100 d flask and stirred in a water bath. 0.5 g of anhydrous aluminum chloride is gradually added thereto. after that,
After continuing stirring for 30 minutes, the mixture was left at room temperature for a while. Ice water was added to the reaction mixture and extracted with ethyl acetate. The separated organic layer was washed with saturated brine and then dried over anhydrous sodium sulfate. After drying, the solvent was distilled off using an evaporator. After column separation of the product, it was dried in vacuo to obtain 12.7 g of needle-like crystals of 3,4.5-1-lyacetoxybenzophenone. Elemental analysis values are C63.5%, H4
,9%.

Next, add the 3, 4,0.
．． 5-) 12.7 g of lyacetoxybenzophenone, 10.0 g of sodium bicarbonate, 150 ml of methanol, and 150 ml of ion-exchanged water were added, and the mixture was stirred at room temperature for 2 hours. The reaction solution was extracted with ethyl acetate, washed successively with water, saturated aqueous sodium bicarbonate, saturated brine, IN aqueous hydrochloric acid, and saturated brine, dried over anhydrous sodium sulfate, and the solvent was distilled off using an evaporator. After column separation of the product, it was dried in vacuo to give yellow powder crystals of 3° and 4.
7.2 g of 5-1-lyhydroxybenzophenone was obtained.

Purity by reverse phase chromatography was 98.3%. Elemental analysis values were C67.4% and H4.6%.

Next, 5.0 g of 3,4゜5-trihydroxybenzophenone and 15.8 g of 1,2-naphthoquinonediazide-5-sulfonyl chloride were added to a 300 mk 3-tube flask.
g in 100 g of dioxane, and at room temperature, with stirring, add 20 a of a solution of 6.8 g of triethylamine in dioxane.
e was added dropwise over 30 minutes. Thereafter, the reaction was continued for 3 hours. After the reaction, triethylamine hydrochloride was filtered off, and the filtrate was poured into a large amount of ion-exchanged water to precipitate a 1,2-quinonediazide compound of 3,4.5-trihydroxybenzophenone. This was filtered, washed sequentially with ion-exchanged water and ethanol, and then dried to a powder of 17.8
I got g. Elemental analysis values are C55.7%, H2.8%,
H was 8.9% and 510.0%.

Synthesis Example 2 According to Synthesis Example 1, 3,4,4--1-dihydroxy-
A 1,2-quinonediazide compound of 3'-methylbenzophenone was synthesized. Elemental analysis values are C56.2%, H
2.8%, H8.8%, and 310.0%.

Synthesis Example 3 According to Synthesis Example 1, a 1°2-quinonediazide compound of 3,4,5,4-tetrahydrokidi-3'-methylbenzophenone was synthesized. Elemental analysis value is C54.8%,
They were H2.9%, H8.6%, and S10.0%.

Synthesis example 4 0-cresol 3 in 4 flasks with 300 rrdl
0g, m-cresol 5'og, p-cresol 50g
, 1.75 g of oxalic acid dihydrate was added. Under nitrogen atmosphere,
Without stirring, the mixture was immersed in an oil bath and heated until the internal temperature reached 100°C. 35% while maintaining internal temperature at 100'C
86 g of formalin aqueous solution was added dropwise over 90 minutes. after that,
The reaction was continued for 15 minutes to synthesize a novolak resin. After the reaction, 120 g of resin powder was obtained by repeating dissolution and precipitation and drying.

As a result of GPCΔIII determination, the weight average molecular weight of the novolac resin was 6850 in terms of polystyrene. In addition, the degree of dispersion (weight average molecule fl/number average molecular weight) is 4.8
It was 5.

Example 1 1,2-quinonediazide compound obtained in Synthesis Example 1 2.15
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 with a 0.2 μm membrane filter.
This was used as a resist solution.

The resist solution was spin-coated onto a 4-inch silicon wafer using a spinner, and prebaked in a circulating constant temperature bath at 90° C. for 30 minutes to obtain a resist film with a thickness of 1.5 μm. Next, a reduction projection exposure device (manufactured by GCA, DSW-630
0ASN, A, -0,35) through the reticle.

Immersion development was performed at 25° C. for 1 minute using a 2.38% by weight aqueous solution of tetramethylammonium hydroxide as a developer.

The exposure dose for one-to-one resolution of 1.0 μm lines/spaces was 158 mJ/cm2.

Also, even in 0.7μm line/space, 160
A one-to-one pattern could be resolved at mJ/cm2, and the mask fidelity was also good.

Furthermore, the exposure dose at which resolution of a 1,0 μm line/space begins is 100 m J/cm2;
No scum was observed within the exposure range from 158 mJ/cm2 to 158 mJ/cm2.

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

Next, resist patterns with 2 μm lines/spaces of 140, 145, 150, 155°160.16
Baking was performed in a circulating constant temperature bath at each temperature of 5,170° C. for 30 minutes, and heat resistance was evaluated based on the presence or absence of pattern deformation. As a result, the heat resistance was 150°C.

Example 2 DSW-630OA is used as a reduction projection exposure apparatus.
A -20= exposure test was carried out according to Example 1, except that an i-line reduction projection exposure apparatus having a lens of ,=0.42 was used.

As a result, the exposure dose for resolving 1.0 μm line/space one-to-one was 162 mJ/cm2. Regarding the resolution, a 0.5 μm line/space could be resolved, and the pattern was rectangular.

Example 3 The 1,2-quinonediazide compound obtained in Synthesis Example 2 was subjected to an exposure test and a heat resistance test according to Example 1.

As a result, the exposure dose for resolving 1.0 μm line/space one-to-one was 153 mJ/cm2. Regarding the resolution, a 0.7 μm line/space could be resolved, and the pattern was rectangular.

Heat resistance was 150°C.

Similarly, according to Example 2, an exposure test and a heat resistance test were conducted.

As a result, the exposure amount for resolving 1.0 μm line/space one-to-one was 157 mJ/cm2. Regarding the resolution, a 0.5 μm line/space could be resolved, and the pattern was rectangular.

Example 4 The 1,2-quinonediazide compound obtained in Synthesis Example 3 was subjected to an exposure test and a heat resistance test according to Example 1.

As a result, the exposure dose for resolving 1.0 μm line/space one-to-one was 168 mJ/cm2. Regarding the resolution, a 0.65 μm line/space could be resolved, and the pattern was rectangular.

Heat resistance was 155°C.

Similarly, according to Example 2, an exposure test and a heat resistance test were conducted.

As a result, the exposure dose for resolving 1.0 μm line/space one to one was 175′ mJ/cm 2 . Regarding the resolution, a 0.5 μm line/space could be resolved, and the pattern was rectangular.

Comparative Example In a 500 ml three-tone flask, 10.0 g of 2,3.4-trihydroxybenzophenone and 31.0 g of 1°2-naphthoquinonediazide-5-sulfonyl chloride were added. ．． 8
A solution of 13.7 g of triethylamine in 100 g of dioxane and 30 g of triethylamine in dioxane was prepared at room temperature without stirring.
ml was added dropwise over 30 minutes. Thereafter, the reaction was continued for 3 hours. After the reaction, i-ethylamine hydrochloride was filtered, and the filtrate was poured into a large amount of ion-exchanged water.
A 1,2-quinonediazide compound of -trihydroxybenzophenone was precipitated. This is filtered, washed sequentially with ion-exchanged water and ethanol, and then dried to form a powder of 35%.
．． 8g was obtained. Elemental analysis value is C55.9%, ■2.6
%, N9.0%, and 810.1%.

2.3.1.2 of 4-1-lyhydroxybenzophenone
- according to Example 1 using a quinonediazide compound,
An exposure test and a heat resistance test were conducted.

As a result, the exposure amount for resolving a 1.0 μm line/space on a one-to-one basis was 153 mJ/cm 2 .

Regarding resolution, 0.7 μm lines/spaces could be resolved, but the pattern profile was poor.

The exposure at which resolution of a 1.0 zzm line/space begins is 95 m J/cm2, but from 95 to 14
Scum generation was observed within the exposure amount range of 0 mJ/cm2.

Heat resistance was 150°C.

Similarly, according to Example 2, an exposure test and a heat resistance test were conducted.

As a result, the exposure dose for resolving 1.0 μm line/space one-to-one was 180 mJ/cm2. Regarding resolution, 0.6 μm lines/spaces could be resolved, but the pattern was trapezoidal.

[Effects of the Invention] The positive photoresist composition comprising the alkali-soluble resin and 1,2-quinonediazide compound of the present invention is ],]
Since the 2-quinonediazide compound consists of a phenolic compound whose substituents at the 2.2' and 6.6-positions are hydrogen and/or lower alkyl groups, it has excellent sensitivity, resolution, heat resistance, and pattern shape. It can demonstrate excellent performance for both g-line and i-line. Therefore, it is suitable for manufacturing semiconductor integrated circuit teeth such as VLSI.

Claims (3)

[Claims] (1) In a positive photoresist material consisting of an alkali-soluble resin and a 1,2-quinonediazide compound, 1,
The 2-quinonediazide compound has the general formula (I), ▲mathematical formula, chemical formula, table, etc.▼(I) [However, A_1, A_2, A_3, A_4, A_5 and A_6 are hydrogen and an alkyl group having 1 to 4 carbon atoms. , carbon number 1~
4 alkoxy group, halogen atom or OD, and at least 3 or more OD. R_1, R_2, R_3,
and R_4 represents hydrogen or an alkyl group having 1 to 4 carbon atoms: D is hydrogen, which may be the same or different, a 1,2-naphthoquinonediazide-4-sulfonyl group, a 1,2-naphthoquinonediazide-5-sulfonyl group, or 1,2-benzoquinonediazide-4-sulfonyl group, at least one of which is quinonediazide: X is a single bond, -CO-
, -COO-, -S-, -SO_2-, -(CH_2)_n-, -C(CH_3)_2-, -C
(CF_3)_2-, -NH- or -(CO)NH(CH_2)_nNH(CO)-, where n represents 1 to 11] 2, 2', 6,
A positive photoresist material comprising a phenolic compound in which the substituent at the 6' position is hydrogen and/or a lower alkyl group. (2) The positive photoresist material according to claim 1, wherein X is a carbonyl group. (3) A pattern forming method using the positive photoresist material according to claim 1 or 2.