JPH02186351A - Photosensitive agent for positive type photoresist - Google Patents

Abstract

PURPOSE:To enhance sensitivity, resolution, heat resistance, and a pattern form by forming a photoresist made of a specified 1,2-quinonediazide compound and an alkali-soluble resin. CONSTITUTION:The photosensitive agent to be used for the positive type photoresist comprises the 1,2-quinonediazide compound represented by formula I in which at least 2 of A1-A10 are -O-D, each independent of each other, and D is -R, -COR, or -SO2R; R is alkyl, aralkyl, or aryl; the rest of them are H, halogen, or alkyl, and at least one is a group having a quinone-diazide group; and X is a single bond, -CO-, -COO-, or the like. The positive type photoresist material comprising the alkali-soluble resin and the 1,2-quinonediazide compound can be used for forming a resist patterns by using ultraviolet rays, far ultraviolet rays, electron beams, X-rays, etc., thus permitting sensitivity, resolution, heat resistance, and process stability to be enhanced.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention provides a positive photoresist comprising an alkali-soluble resin and a 1,2-quinonediazide compound that 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 materials and pattern forming methods. [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 material consists of an alkali-soluble novolak resin and a 1,2-quinonediazide compound that functions as an alkali dissolution inhibitor. In the radiation irradiated area, the 1,2-quinonediazide compound becomes ketene via carbene, reacts with moisture inside and outside the system to produce indene carboxylic acid, and is dissolved in the aqueous alkaline solution in the container. 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 highly resolvable resist pattern can be obtained. Conventional cyclized polyisoprene-based negative resists have limited resolution due to swelling of the film during development, and 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. 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. [The problem that the invention seeks to solve”: fJ] 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 lowering the F of other characteristics. Furthermore, in the case of ultraviolet light as an exposure source, for example, its wavelength is shifting from g-line to ivA. conventional g
If a line resist is exposed using an i-line reduction projection exposure apparatus, the pattern profile will be significantly deteriorated, which will lead to a decrease in resolution. In addition, although various resists that can be used with either the g-line or the i-line are being developed, a resist that can be used with both light sources, as desired by users, has not yet been developed.

[Means to solve the problem]

As a result of extensive research based on this background, the present inventors have found that when all hydroxyl groups of a phenolic compound are replaced as a photosensitizer, the absorption of the i-line is lowered and the resist properties for the i-line are improved. It has been found that the photosensitive agent can be applied to G-line as well, and has high sensitivity, high resolution, and high process stability. In particular, the inventors have found that when some of the substituents are not photosensitive components, the solubility in a developing solution is improved and the resist properties are dramatically improved, leading to the completion of the present invention. Furthermore, it has been found that when some of the substituents are not photosensitive components, the storage stability of the resist solution is also improved. That is, the present invention provides at least 2 of general formula (1) % formula % Δ7 , A, , Ag and All+
each is independently a group represented by 10-D (where D is R
, COR or -So, R ((R represents an alkyl group, aralkyl group or aryl group which may have a substituent)) or a 1,2-naphthoquinonediazide-4-sulfonyl group, 1゜2 -naphthoquinonediazide-5-sulfonyl group or 1,2-benzoquinonediazide-4-sulfonyl group), and the remainder is a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms, respectively. AI (, at least one of which is a group containing a quinonediazide group, X is a single bond, -
co--coo--s--5o- -SO□-(CH2) -C(CH3)2 -C(CFi)2--NH- or (CO)NH(CH2) NH(Co) group (n is a number represented by 1 or 2)] A photosensitizer for positive photoresists is provided. Furthermore, the present invention provides a positive photoresist composition comprising the photosensitive agent for positive photoresists and an alkali-soluble resin, and a pattern forming method using the positive photoresist composition. Note that AI, A2, and AI in general formula (I). A4, As, Ab, A? , A8 , A9, Alo
Examples of the alkyl group include methyl group, ethyl group, propyl group, butyl group, etc., and halogens include chlorine, fluorine,
Examples include bromine. Examples of the alkyl group of R include methyl group, ethyl group, propyl group, butyl group, etc., examples of the aryl group include phenyl group, naphthyl group, etc., and examples of the aralkyl group include benzyl group, phenethyl group, cumyl group, etc. Can be done. Examples of substituted alkyl groups include fluorine-substituted alkyl groups and alkoxyalkyl groups, and examples of substituted aryl groups include alkyl-substituted phenyl groups such as tolyl and ethylphenyl, fluorine-substituted phenyl groups, and benzoic acid. The method for synthesizing the 1,2-quinonediazide compound represented by general formula (1) in the present invention is not particularly limited, but it can be synthesized, for example, by the following method. The following general formula (n) [However, B, Bz, B3, B4, BS, B6, B
At least two of y, Bs, Bq and B1° are hydroxyl groups, and the remainder each represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms, and X is a single bond, -CO-
-COO--9- -S O-S O2--(CH2) NH--C(CH))z -C(CFi)2- or (Co)NH(CH2), NH(,CO) 2
1.2-
naphthoquinonediazide-4-sulfonyl chloride, 1,
The rest is esterified with 2-naphthoquinonediazide-5-sulfonyl chloride or 1°2-benzoquinonediazide-4-sulfonyl chloride in the presence of a base such as potassium hydroxide, sodium hydroxide, alkali carbonate, triethylamine, or pyridine. It can be synthesized by Furthermore, when esterifying with a substituent other than a photosensitive group, the desired product can be obtained even if the esterification is performed simultaneously with a 1,2-quinonediazide group. 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) is preferred. 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,
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, benzoic acid, naphthyl, benzyl, cumyl, and phenethyl. The 1,2-quinonediazide compound of the present invention is preferably used in an amount of 20 to 50 parts 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 in a solid content of 20%.
Dissolve f'7 in an appropriate solvent to make ~40 parts by weight.
It will be done. 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 than those of the present invention can also be used for OL. Furthermore, if necessary, nonionic, fluorine-based, silicone-based surfactants, etc. can be added in order to improve the solubility, and other sensitizers, color toners,
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. Then, a resist film is obtained by spin-coding the cyst solution onto a substrate such as a silicon wafer and bre-baking. 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. Further, the wafer may be subjected to heat treatment after exposure. 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, blebake, exposure, development, etc. 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 4.9 g of 2,3.4゜4゛-tetrahydroxybenzophenone and 0.9 g of propionic acid chloride were dissolved in 50 g of dioxane in a 300-Ij 3-tube flask, and 1.1 g of triethylamine was dissolved at room temperature while stirring. 50 d of 1 g of dioxane solution was added dropwise over 30 minutes. after that,
A solution of 18.8 g of 1.2-naphthoquinonediazide-5-sulfonyl chloride and 50 g of dioxane was added dropwise over 30 minutes, and then a dioxane solution of 50rR1 containing 7.8 g of triethylamine was added dropwise over 30 minutes. Thereafter, the reaction was continued for 3 hours. After the reaction, triethylamine hydrochloride is
After filtration, the filtrate was poured into a large amount of ion-exchanged water, and 2
, 3.4. An ester compound of 4-tetrahydroxybenzophenone was precipitated. This is filtered, washed sequentially with ion-exchanged water and ethanol, and then dried to a powder of 20. I got og. Elemental analysis values are C55.1%, H2.6%, N8.9%
, 510.0%. Synthesis Example 2 According to Synthesis Example 1, 4.9 g of 2,3.4.4''-tetrahydroxybenzophenone was mixed with 1.9 g of ethoxyacetic acid chloride.
After esterification with 2 g, esterification was performed with 18.8 g of 1°2-naphthoquinonediazide-5-sulfonyl chloride to obtain a powder weighing 19.3 g after drying. Elemental analysis values are C54.8%, H2.7%, N8.8%,
S was 9.8%. Synthesis Example 3 According to Synthesis Example 1, 4.9 g of 2.3.4.4=-tetrahydroxybenzophenone was esterified with 1.3 g of p-benzoic acid sulfonyl chloride, and then 1,2-naphthoquinonediazide-5-sulfonyl Esterification was performed with 19.9 g of chloride to obtain a powder weighing 19.5 g after drying. Element 11? Values are C54, 3%, H2, 4%
, N9.1%, 310.796. Synthesis Example 4 According to Synthesis Example 1, 5.0 g of 2,3,4.2-4'' pentahydroxybenzophenone was esterified with 1.2 g of ethoxyacetic acid chloride, and then 1,2-naphthoquinonediazide-5-sulfonyl It was esterified with 23.0 g of chloride to obtain a powder weighing 22.3 g after drying.The elemental analysis values were: C53.4%, H2.6%, N9.5
%, 510.4o6. Synthesis-15 According to synthesis vr1i, 2,3,4.4-tetrahydroxybenzophenone 5. Og was esterified with 13.6 g of 1,2-naphthoquinonediazide-5-sulfonyl chloride to obtain a powder weighing 15.5 g after drying. Elemental analysis values are C54.8%, H2.6%, N8.5
%, 89.4%. Synthesis Example 6 0-Cresol 30 in a 300ml 4 flask
g s m-cresol 50g5p-cresol 50
g1 1.75 g of oxalic acid dihydrate and 86 g of a 37% formalin aqueous solution 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. Internal temperature 10
The reaction was continued for 60 minutes while maintaining the temperature at 0°C. after that,
The external temperature was raised to 180°C, and dehydration and monomer removal were performed under reduced pressure for 1 hour. After cooling, repeat the process of dissolution and precipitation.
By drying, 120g of novolak resin powder
I got it. The weight average molecular weight of novolac resin is G P Cil#
The J constant was 8900 in terms of polystyrene. Further, the degree of dispersion (weight average molecular weight/number average molecular m>) is 4.
It was 85. Example 1 1,2-quinonediazide compound 2 obtained in Synthesis Example 1, Og
and the novolak resin obtained in Synthesis Example 69. The solution was dissolved in 25 g of ethylene glycol monoethyl ether acetate and passed through a 082 μm membrane filter to obtain a resist solution. The resist solution was spin-coated onto a 4-inch silicon wafer using a spinner and heated to 80°C.
, Brebake on a hot plate for 90 seconds, 1
．． A resist film with a thickness of 5 μm was obtained. Next, exposure was performed through the reticle using a reduction projection exposure apparatus (manufactured by GCA, DSW-6300A, N, A, -0,35). After exposure, it was heated on a hot plate at 100° C. for 90 seconds, and then developed. An immersion phenomenon was performed at 25° C. for 1 minute using a 2.38 weight 96 aqueous solution of tetramethylammonium hydroxide as a developer. The exposure dose for one-to-one resolution of 1.0 μm lines/spaces was 255 mJ/cm2. Also, bs 2 in 0.65 μm line/space
55mJ/crn"?'1:1 pattern resolution,
Mask fidelity was also good. Regarding the resolution, a 0.6 μm line/space could be resolved, and the pattern was rectangular. Next, resist patterns of 2 μm lines/spaces are respectively 120.125.130.135.140.14.
5. Baking was performed on a hot plate at each temperature of 150° C. for 5 minutes, and heat resistance was evaluated based on whether the pattern was deformed or not. As a result, the heat resistance was 135°C. Example 2 DSW-6300A is used as a reduction projection exposure apparatus.
An exposure test was carried out in accordance with Example 1, except that the exposure apparatus was replaced with an i-line reduction projection exposure apparatus having a lens of -0.40. As a result, the exposure amount for resolving 1.0 μm line/space one to one was 270 mJ/crn2. 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 a g-line 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 213 mJ/cm2. Regarding resolution, 0.55 μm lines/spaces could be resolved. Heat resistance was 135°C. Similarly, according to Example 2, an i-line exposure test was conducted. As a result, the exposure dose for resolving 1.0 μm line/space at a ratio of 1:1 was 230 mJ/cm′. Regarding the quadrature, 0.5 μm lines/spaces could be resolved, and the pattern was rectangular. Example 4 In the 1,2-quinonediazide compound obtained in Synthesis Example 3, g-line We conducted an exposure test and a heat resistance test at
=. Regarding the resolution, a 0.60 μm line/space could be resolved, and the pattern was rectangular. Heat resistance was 140°C. Similarly, according to Example 2, a one-line exposure test was conducted. As a result, the exposure dose for resolving 1.0 μm line/space one-to-one was 180 mJ/cm2. Regarding the resolution, a 0.5 μm line/space could be resolved, and the pattern was rectangular. Example 5 The j-star 1,2-quinonediazide compound in Synthesis Example 4 was subjected to a g-line exposure test and a heat resistance test in accordance with Example 1. As a result, the exposure amount for resolving 1.0 μm line/space one to one was 270 mJ/cm 2 . Regarding the resolution, a 0.6 μm line/space could be resolved, and the pattern was rectangular. Heat resistance was 140°C. Similarly, according to Example 2, an i-line exposure test was conducted. As a result, the exposure dose for resolving 1.0 μm lines/spaces on a one-to-one basis was 300 mJ/cm''.As for the resolution, 0.5 μm lines/spaces could be resolved, and a rectangular pattern Comparative Example The 1,2-quinonediazide compound obtained in Synthesis Example 5 was subjected to an i-line exposure test according to Example 2. As a result, 1,0 μm line/space was resolved on a one-to-one basis. The exposure dose for imaging was 230 mJ/cm2, but regarding the resolution, the pattern shape of 0.55 μm line/space was trapezoidal.The following is a summary of embodiments of the present invention. (1) 1, which does not have aquatic group as a substituent in the nucleus and may have a group not containing a 1,2-quinone azide group in the oxygen atom substituted in the nucleus, ] A photosensitizer for positive photoresists comprising a compound that is The photosensitizer for positive photoresists according to the above embodiment (1), in which the oxygen atom has a group containing a 1,2-quinonediazide group. (3) The above embodiment, in which X in the general formula (I) is a carbonyl group. (2) Photosensitive agent for positive photoresist. (4)
The ratio of the number of groups not containing a 1.2-quinonediazide group and the number of groups containing a 1.2-quinonediazide group bonded to an oxygen atom substituted in the nucleus is 0.1:99.9 to 50:50.
The photosensitizer for positive photoresists according to the embodiment (2) or (3) above. C. Effects of the Invention] The positive photoresist composition comprising the 1,2-quinonediazide compound and the alkali-soluble resin of the present invention has the following effects:1.
Since the 2-quinonediazide compound is composed of a phenolic compound in which the hydroxyl group is substituted, sensitivity, resolution,
It has excellent heat resistance and pattern shape, and in particular, has very low absorption of i-line, so it can exhibit excellent performance for both g-line and i-line. In particular, when the photosensitive component is partially substituted with a substituent that is not a photosensitive component, the resist properties are further improved. Therefore, it is suitable for manufacturing semiconductor integrated circuit elements such as VLSI.

Claims (3)

[Claims] (1) General formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) [However, A_1, A_2, A_3, A_4, A_5, A
At least two of _6, A_7, A_8, A_9 and A_1_0 are each independently a group represented by -OD (however, D is a group represented by R, COR or -SO_2R ((R is a group having a substituent) 1,2-naphthoquinonediazide-4-sulfonyl group, 1,2-naphthoquinonediazide-5-sulfonyl group or 1,2-benzoquinonediazide-4-sulfonyl group) ), and
The remainder each has a hydrogen atom, a halogen atom, or a carbon number of 1 to
4, at least one of A_1 to A_1_0 is a group containing a quinonediazide group,
X is a single bond, -CO-, -COO-, -S-, -SO-
, -SO_2-, -(CH_2)_n-, -C(CH_3)_2-, -C(CF_3)_2-, -
A photosensitizer for positive photoresists comprising a compound represented by a group represented by NH- or -(CO)NH(CH_2), NH(CO)- (n is a number represented by 1 or 2). (2) A positive photoresist composition comprising the photosensitizer for positive photoresists according to claim 1 and an alkali-soluble resin. (3) A pattern forming method using the positive photoresist composition according to claim 2.