KR100195582B1 - Copolumer for matrix resin of chemical amplified positive photoresist composition and the chemical amplified photoresist composition containing the same - Google Patents

Abstract

The present invention relates to a copolymer having a repeating unit represented by the following general formula (I) and a chemically amplified positive photoresist composition composed of the copolymer and a photoacid generator.

Here, l, m, and n are numbers representing repeating units, respectively, 0.1 ≦ L / m + n ≦ 0.5, 0 ≦ m / L + n ≦ 0.5, and 0 ≦ n / L + m ≦ 0.9.

The present invention improves the etching resistance by introducing an alicyclic chain to a polyacrylate derivative having low light absorption at 193 nm, improved adhesion by introducing a monomer having a hydroxyl group introduced therein, and the concentration of the developer during development. It could be developed without changing it. Therefore, according to the present invention, a chemically amplified resist was prepared by preparing a copolymer which was easily synthesized, and then a resist pattern having excellent high resolution and etching resistance regardless of the type of substrate.

Description

Copolymer for matrix resin of chemically amplified positive photoresist composition and chemically amplified photoresist composition containing same

The present invention relates to a copolymer for matrix resin of a chemically amplified positive photoresist composition and a chemically amplified positive photoresist composition containing the same. More specifically, it relates to a copolymer represented by the following general formula (I) and a chemically amplified positive photoresist composition composed of the copolymer and a photoacid generator.

Where R is a hydrogen atom or an alkyl group, and l, m and n are the numbers representing the repeating units, respectively, 0.1 ≦ L / m + n ≦ 0.5, 0 ≦ m / L + n ≦ 0.5, and 0 ≦ n / L. + m ≤ 0.9.

In recent years, for high integration of semiconductor devices, research on lithography technology has come to the fore. Lithography techniques mostly rely on light sources, but techniques using g-rays (wavelength 436 nm) and i-rays (365 nm wavelength) have shown limitations in the fabrication of highly integrated semiconductor devices. Accordingly, the use of excimer lasers such as far ultraviolet rays, KrF lasers, ArF lasers, X-rays, and electron beams as light sources used in lithography processes for high integration of semiconductor devices is actively underway. Therefore, the development of a resist according to the change of the light source is essential.

Conventional photoresists used for g-rays and i-rays are resists using novolak-quinonediazide compounds, and when the compound is used in far ultraviolet rays or KrF excimer lasers, the novolak-quinonediazide compounds are ultraviolet rays. The absorption of light is large in the vicinity, so its use has been limited. Therefore, chemically amplified photoresists using polyhydroxystyrene derivatives having relatively low absorption than novolak-quinonediazide compounds as base resins have been used in light sources such as ultraviolet rays and KrF excimer lasers. The chemically amplified resist contains a resin having a functional group decomposed by reaction with an acid and a compound (hereinafter, referred to as a photoacid generator) which generates an acid by irradiation with radiation. However, although it can be used in the chemically amplified resist KrF excimer laser using a polyhydroxy styrene derivative, the wavelength of ArF excimer laser (193 nm), which is shorter than that, is not suitable for use due to the large absorption of light. Therefore, in order to compensate for this, many studies on chemically amplified photoresists using polyacrylate derivatives having low light absorption at a wavelength of 193 nm have been conducted. However, in the case of polyacrylate derivatives, although light absorption is small at 193 nm, etching resistance is inferior to that of novolak resins or polyhydroxystyrene derivatives.

On the other hand, in order to satisfy the high resolution resist pattern, the adhesion between the composition of the resist and the substrate acts as an important factor. In the past, carboxylic acid derivatives were introduced to improve adhesion to the substrate. However, the carboxylic acid derivatives are difficult to be used in the process of reducing the concentration of the developer during development because of their high solubility in aqueous alkali solution. There are disadvantages.

The present invention improves the etching resistance by introducing an early cyclic chain to the polyacrylic derivatives to improve these disadvantages and at the same time improve the adhesion by introducing a monomer having a hydroxyl group introduced, and can be developed without changing the concentration of the developer during development. Compounds that can be developed. Therefore, according to the present invention, a chemically amplified resist was prepared by preparing a copolymer which was easily synthesized, and then a resist pattern having excellent high resolution and etching resistance regardless of the type of substrate.

An object of the present invention is to provide a copolymer in which the repeating unit is represented by the following general formula (I).

Here, l, m, and n are numbers representing repeating units, respectively, 0.1 ≦ L / m + n ≦ 0.5, 0 ≦ m / L + n ≦ 0.5, and 0 ≦ n / L + m ≦ 0.9.

Another object of the present invention is to provide a chemically amplified positive photoresist composition composed of a copolymer represented by the general formula (I) and a photoacid generator.

The copolymer for matrix resin of the chemically amplified positive photoresist composition of the present invention has a repeating unit represented by the following general formula (I), and has a weight average molecular weight of 1,000 to 1,000,000 in terms of polystyrene, and a molecular weight distribution (Mw / Mn). ) Is 1.0 to 1.5.

Here, l, m, and n are numbers representing repeating units, respectively, 0.1 ≦ L / m + n ≦ 0.5, 0 ≦ m / L + n ≦ 0.5, and 0 ≦ n / L + m ≦ 0.9.

First, the copolymer in which the repeating unit is represented by the general formula (I) is a monomer represented by the following structural formula (II), a norbornene monomer represented by the following structural formula (III) and a male represented by the following structural formula (IV). Maleic anhydride monomers can be prepared in the presence of a polymerization catalyst.

The monomer represented by Structural Formula (II) may be polymerized into a copolymer or terpolymer with monomers represented by Structural Formula (III) and Structural Formula (IV), respectively. It can also superpose | polymerize and use as a matrix resin.

Such copolymers or terpolymers may be block copolymers, random copolymers or graft copolymers. The polymerization method of the copolymer represented by the general formula (I) can be carried out by various methods such as radical polymerization, cationic polymerization or anionic polymerization, of which radical polymerization is most preferred. As the reaction solvent, a general organic solvent may be used. That is, it is an aromatic hydrocarbon, a cyclic ether, an aliphatic hydrocarbon, and benzene, toluene, xylene, dioxane, tetrahydroxyfuran, hexane, cyclohexane, diethoxyethane, etc. are mentioned specifically ,. These may be used in combination of two or more or alone. In addition, polymerization initiators used for radical polymerization include azobisisobutyronitrile (hereinafter referred to as AIBN), benzoyl peroxide, lauryl peroxide, azobisisocapronitrile and azobis There is no particular limitation as long as it is used as a general radical polymerization initiator such as isovaleronitrile and t-butylhydroperoxide.

The reaction is performed while stirring in an atmosphere of an inert gas such as argon or nitrogen. The polymerization is carried out for 1 to 48 hours. The polymerization temperature may vary depending on the type of polymerization initiator. For example, when azobisisobutyronitrile is used as a polymerization initiator, 60-90 degreeC is suitable. After the reaction, a solvent capable of dissolving the polymerized product, for example, dichloromethane, tetrahydrofuran, methanol or the like is added to the reaction system to stop the reaction, and then the reaction mixture obtained is a suitable solvent such as water, hexane, heptane and methanol. The copolymer can be obtained by, for example, precipitating on the back and then filtering and drying. The molecular weight of the copolymer can be adjusted according to the reaction time and the amount of polymerization initiator used. If the molecular weight is small, the coating properties and heat resistance is poor, if the molecular weight is too large, there is a disadvantage that the sensitivity, developability, and the like. Therefore, the molecular weight of the copolymer may be 1,000 to 1,000,000, but preferably 4,000 to 80,000. Moreover, molecular weight distribution (Mw / Mn) is 1.0-5.0, Preferably 1.2-2.5 are suitable. After the end of the polymerization, the residual amount of monomer should be 10% by weight or less based on the resultant copolymer, and preferably 3% by weight or less.

The chemically amplified positive photoresist composition of the present invention is composed of a matrix resin and a copolymer having a repeating unit represented by the general formula (I) and a photoacid generator.

Examples of the photoacid generator used in the composition of the present invention include onium salt-based iodide salts, sulfonium salts, phosphonium salts, diazonium salts, pyridinium salts, and the like, and among these salts, triphenylsulfonium tri Plate, diphenyl (4-methylphenyl) sulfonium triflate, diphenyl (4-t-butylphenyl) sulfonium triflate, diphenyl (4-methoxyphenyl) sulfonium triflate, diphenyl (naphthalene -1-yl) sulfonium triflate, triphenylsulfonium hexafluoroantimonate, diphenylidonium triflate, diphenyliodium methylbenzenesulfonate, bis (cyclohexylsulfonyl) diazo Methane and bis (2,4-dimethylphenylsulfonyl) diazomethane are particularly preferred. Examples of the halogen compound include 1,1-bis (4-chlorophenyl) -2,2,2-trichloroethane, phenyl-bis (trichloromethyl) -s-triazine and naphthyl-bis (trichloromethyl) -s -Triazine. Besides these, there are 1,3-diketo-2-diazo compounds, diazobenzoquinone compounds, diazonaptoquinone compounds which are diazoketone compounds, and sulfone compounds, sulfonic acid compounds, nitrobenzyl compounds and the like. Particularly preferred compounds among these photoacid generators are onium salt compounds and diazoketone compounds. The photoacid generator is used in an amount of 0.1 to 30 parts by weight, in particular 0.3 to 10 parts by weight, based on 100 parts by weight of the total solid component. Said photo-acid generator can be used individually or in mixture of 2 or more types.

The composition of this invention can use an additive as needed. Such additives include surfactants, azo compounds, antihalation agents, adhesion aids, storage stabilizers, and antifoaming agents. Examples of the surfactant include polyoxylauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyethylene glycol dilaurylate and the like. These surfactants are preferably used in an amount of 2 parts by weight or less based on 100 parts by weight of the total solid component.

In addition, a basic compound may be used to prevent diffusion of acid generated after exposure. Examples of the basic compound include amine compounds and ammonium compounds. For example, triethyl amine and tetramethylammonium hydroxide. The addition amount of basic compound is 0.05-5 weight part with respect to a total solid component. If the amount is larger than this, the diffusion of the acid is reduced, but the sensitivity is lowered.

The photoresist composition in the present invention is usually used after being dissolved in a suitable solvent. In order to obtain a uniform and flat coating film, it is used by dissolving in a solvent having a suitable evaporation rate and viscosity. Examples of the solvent having such physical properties include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, Diethylene glycol dibutyl ether, methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, methyl ethyl ketone, cyclohexanone, methyl 2- Hydroxypropionate, ethyl 2-hydroxypropionate, 2-heptanone, N-methylpyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, ethyl pyruvate, n-amyl Acetate, ethyl lactate, gamma-butyrolactone, and the like, In some cases, these alone or two or more mixed solvents are used. The amount of the solvent is adjusted to be uniformly formed on the wafer using an appropriate amount depending on the physical properties of the solvent used, ie volatility, viscosity, and the like.

The composition of the present invention can be subjected to a lithography process by a conventional method, and as a developer used at the time of development, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, tri It is selected from an aqueous solution containing ethylamine, tetramethyl ammonium hydroxide, tetraethylammonium hydroxide and the like. Among these, tetramethylammonium hydroxide is preferable. If necessary, surfactants, water-soluble alcohols and the like can be used as additives. After using such a developing solution, it is usually preferable to wash with water after developing.

Therefore, the present invention can be used for light sources such as ultraviolet rays, far ultraviolet rays, KrF excimer lasers, and further ArF excimer lasers, and have excellent storage stability, etching resistance, resolution, and the like. Can be.

The present invention is specifically described by the following synthesis examples and examples. However, the present invention is not limited to these synthesis examples and examples.

Monomer Synthesis

Synthesis Example 1

48.86 g of 5-norbornene-2-carboxaldehyde and 93.91 g of t-buty1 bromoacetate are dissolved in 400 ml of tetrahydrofuran. The solution was reacted at 80 ° C. for 1 hour using a Zn-Cu couple catalyst prepared in a conventional manner. After the reaction the reaction is cooled and neutralized with acid. After neutralization, the mixture was extracted with ether, washed 2-3 times with saturated aqueous sodium chloride solution, the organic layer was separated, dried over anhydrous magnesium sulfate, filtered and the solvent was completely removed. The reaction product from which the solvent was completely removed was purified using silica gel column chromatography to obtain 3-bicyclo [2.2.1] hept-5-en-2-yl-3-hydroxy- having the structure of formula (II ′). 120 g of propionoc acid tert-butyl ester) was obtained.

Synthesis Example 2

25 g of the monomer obtained in Synthesis Example 1 was dissolved in 1,000 ml of ethanol. The palladium catalyst was placed therein, reduced to hydrogen at room temperature for 10 hours, and then filtered to remove the catalyst. The solvent was completely removed to form 3-bicyclo [2.2.1] hept-2-yl-3-hydroxy-propionic acid t-butyl ester of the following formula (II ″) (3-bicyclo [2.2.1] hept-2 24 g of -yl-3-hydroxy-propionoc acid tert-butyl ester) were obtained.

Synthesis Example 3

24 g of the monomer of formula (II ″) obtained in Synthesis Example 2 and 14 g of methacryloyl chloride were dissolved in 400 ml of dichloromethane, and the reactor was cooled to 0 ° C., and 15 g of triethylamine was slowly added dropwise thereto. After dropping, the mixture is stirred at room temperature for 4 hours. After stirring 2-3 times with saturated aqueous NaCl solution, the organic layer was separated, dried over anhydrous magnesium sulfate, filtered and the solvent was completely removed. The reaction product from which the solvent was completely removed was purified using silica gel column chromatography to obtain 3-bicyclo [2.2.1] hept-2-yl-3- (2-methyl-alkoxy) having the structure of Formula (II). 18 g of t-butyl ester (3-bicyclo [2.2.1] hept-2-yl-3- (2-mehtyl-allyloxy) tert-butyl ester) was obtained.

Copolymer Synthesis

Synthesis Example 4

9.26 g of the compound of formula II of Synthesis Example 3, 5.51 g of 5-norbornen-2-ol, 4.90 g of maleic anhydride, and AIBN 0.059 as a polymerization initiator After dissolving g in 35 ml of toluene and injecting nitrogen into the reactor to make the inside of the reactor completely in a nitrogen atmosphere, the reaction temperature was raised to 80 ° C. and stirred for 24 hours. After the polymerization, tetrahydrofuran was added to terminate the polymerization, and the resin was added dropwise to 1,000 ml of methanol to obtain a white precipitate, which was filtered and dried in vacuo for 20 hours to obtain 15.0 g of resin (1). The weight average molecular weight (polystyrene conversion, abbreviated below) of resin was 18,000.

Synthesis Example 5

3.30 g of the compound of formula (II) of Synthesis Example 3, 5.88 g of maleic hydride and 5.83 g of AIBN were dissolved in 31 ml of toluene, and nitrogen was introduced into the reactor to make the inside of the reactor completely nitrogen atmosphere, and then the reaction temperature was decreased. The temperature is raised to 80 ° C. and stirred for 24 hours. After the polymerization, methylene chloride was added to stop the polymerization, and the resin was added dropwise to 1,000 ml of hexane to obtain a white precipitate. The mixture was filtered and dried in vacuo for 20 hours to obtain 12.0 g of resin (2). The weight average molecular weight of resin was 13,000.

Synthesis Example 6

The polymerization was carried out in the same manner as in Synthesis Example 4 except for using t-buty1 hydroperoxide instead of AIBN as a polymerization initiator, to obtain 14.8 g of Resin (3). The weight average molecular weight of the resin was 17,000. .

Example 1

100 parts by weight of the resin (1) obtained in Synthesis Example 4 and 1.0 part by weight of triphenylsulfonium triflate as a photoacid generator were dissolved in 400 parts by weight of methyl 3-methoxypropionate, and then the solution was filtered through a 0.1 μm membrane filter. A solution was obtained.

The resist thus obtained was applied to a silicon wafer using a spinner and dried at 110 ° C. for 60 seconds to obtain a film having a thickness of 0.6 μm. The film was exposed through a pattern chrome mask using a 193 nm ArF excimer laser stepper and then heat treated at 110 ° C. for 90 seconds, followed by development, washing and drying for 60 seconds with a 2.38 wt% tetramethylammonium hydroxide aqueous solution. Formed.

The resist thus formed obtained a line-and-space pattern of 0.30 mu m at an exposure dose of 46 mJ / cm 2.

Example 2

100 parts by weight of the resin (1) obtained in Synthesis Example 4 and 5.0 parts by weight of triphenylsulfonium triflate were dissolved in 400 parts by weight of methyl 3-methoxypropionate. A resist pattern was formed in the same manner as in Example 1 except that 40 mol% of tetramethyl ammonium hydroxide was added to the resist with respect to triphenylsulfonium triflate as a photoacid generator.

The resist thus formed obtained a line-and-space pattern of 0.20 mu m at an exposure dose of 56 mJ / cm 2.

Example 3

A resist pattern was formed in the same manner as in Example 1 except that the resist of Example 1 was left for 1 hour after the exposure treatment and then heated at 110 ° C. for 90 seconds. The resist thus formed obtained a line-and-space pattern of 0.25 mu m at an exposure dose of 50 mJ / cm 2.

Example 4

A resist pattern was formed in the same manner as in Example 1 except that 4.5 parts by weight of triphenylsulfonium hexafluoroantimonate was used instead of 5.0 parts by weight of triphenylsulfonium triflate used in Example 2.

The resist thus formed obtained a line-and-space pattern of 0.20 mu m at an exposure dose of 30 mJ / cm 2.

Example 5

100 parts by weight of the resin (2) obtained in Synthesis Example 5 and 5.4 parts by weight of triphenylsulfonium triflate were dissolved in 400 parts by weight of methyl 3-methoxypropionate. A resist pattern was formed in the same manner as in Example 1 except that 45 mol% of tetramethyl ammonium hydroxide was added to the resist with respect to the photoacid generator.

The resist thus formed obtained a line-and-space pattern of 0.30 mu m at an exposure dose of 74 mJ / cm 2.

Example 6

A resist pattern was formed in the same manner as in Example 1 except that 4.6 parts by weight of triphenylsulfonium hexafluoroantimonate was used instead of 5.4 parts by weight of triphenylsulfonium triflate used in Example 5.

The resist thus formed obtained a line-and-space pattern of 0.25 mu m at an exposure dose of 40 mJ / cm 2.

Example 7

100 parts by weight of the resin (3) obtained in Synthesis Example 6 and 1.2 parts by weight of triphenylsulfonium triflate were dissolved in 400 parts by weight of methyl 3-methoxypropionate, and then a resist pattern was formed in the same manner as in Example 1. It was.

The resist thus formed obtained a line-and-space pattern of 0.30 mu m at an exposure dose of 46 mJ / cm 2.

Example 8

100 parts by weight of the resin (3) obtained in Synthesis Example 6 and 5.0 parts by weight of triphenylsulfonium triflate were dissolved in 400 parts by weight of methyl 3-methoxypropionate. A resist pattern was formed in the same manner as in Example 1 except that 40 mol% of tetramethyl ammonium hydroxide was added to the resist with respect to triphenylsulfonium triflate as a photoacid generator.

The resist thus formed obtained a line-and-space pattern of 0.20 mu m at an exposure dose of 58 mJ / cm 2.

The positive photoresist prepared using the resin for preparing the photoresist of the present invention is suitable for using any radiation including i-ray which is ultraviolet ray, excimer laser which is far ultraviolet ray, X-ray, electron beam which is charged particle beam, etc., and has high sensitivity. It has high resolution, heat resistance, etching resistance, and excellent post-exposure storage stability, and is suitably used as a photoresist for manufacturing semiconductor devices in which micronization proceeds. An excellent resist pattern can be obtained regardless of the type of substrate.

Claims (4)

A repeating unit is represented by the following general formula (I), the polystyrene reduced weight average molecular weight is 1000-1 million, and molecular weight distribution (Mw / Mn) is 1.0-5.0 The copolymer for matrix resin of the chemically amplified positive photoresist composition.

Here, l, m, and n are numbers representing repeating units, respectively, 0.1 ≦ L / m + n ≦ 0.5, 0 ≦ m / L + n ≦ 0.5, and 0 ≦ n / L + m ≦ 0.9. A chemically amplified positive photoresist composition comprising a copolymer represented by the following general formula (I) and a photoacid generator as a matrix resin.

L, m, and n are numbers representing repeating units, respectively, and 0.1 ≦ L / m + n ≦ 0.5, 0 ≦ m / L + n ≦ 0.5, and 0.1 ≦ n / L + m ≦ 0.9. The method of claim 2, wherein the photoacid generator is triphenylsulfonium triflate, diphenyl (4-methylphenyl) sulfonium triflate, diphenyl (4-t-butylphenyl) sulfonium triflate, diphenyl ( 4-methoxyphenyl) sulfonium triflate, diphenyl (naphthalen-1-yl) sulfonium triflate, triphenylsulfonium hexafluoroantimonate, diphenyliodium triflate, diphenyl Denium methylbenzenesulfonate, bis (cyclohexylsulfonyl) diazomethane, bis (2,4-dimethylphenylsulfonyl) diazomethane, 1,1-bis (4-chlorophenyl) -2,2,2 A chemically amplified positive photo characterized in that at least one selected from trichloroethane, phenyl-bis (trichloromethyl) -s-triazine and naphthyl-bis (trichloromethyl) -s-triazine is used. Resist composition. The chemically amplified positive photoresist composition according to claim 2, wherein the photoacid generator is used in an amount of 0.1 to 30 parts by weight based on 100 parts by weight of the copolymer.