JP2005134923A - Acid generating agent for resist - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an acid generating agent for a resist suitable for being used for realizing a positive resist composition which has excellent transmitting property for radiation, in particular, for deep-UV rays and KrF, ArF excimer laser light, high sensitivity, high resolution, excellent heat resistance, focal depth width characteristics, post exposure delay and storage stability of a resist solution, and no dependency on a substrate, and which can produce a resist pattern with an excellent profile. <P>SOLUTION: The acid generating agent comprises a mixture of at least bis(cyclohexyl sulfonyl)diazomethane and bis (2,4-dimethylphenylsulfonyl)diazomethane. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an acid generator for resists, and in particular, has high sensitivity, high resolution, heat resistance, depth of focus characteristics, stability over time and storage stability of resist solutions, and substrate dependency. Chemical amplification type that is sensitive to radiation such as excimer lasers such as ultraviolet rays, far ultraviolet rays, KrF, and ArF, X-rays, and electron beams, and that is capable of forming resist patterns with excellent profile shapes. The present invention relates to a resist acid generator suitable for use in the positive resist composition.

  Conventionally, semiconductor elements such as IC and LSI have been manufactured several times by repeating processes such as photolithography, etching, impurity diffusion and wiring formation using a photoresist composition. In photolithography, a photoresist composition is applied onto a silicon wafer by spin coating or the like to form a thin film, which is irradiated with radiation such as ultraviolet rays through a mask pattern and developed to form a resist pattern. Etching is performed using the resist pattern as a protective film. So far, the photoresist composition used in the photolithography has the required resolution of submicron (1 μm or less) and half micron (0.5 μm or less), and the g-line (436 nm). In addition, a positive photoresist having an alkali-soluble novolak resin utilizing ultraviolet rays such as i-line (365 nm) and a quinonediazide group-containing compound as basic components could be sufficiently put into practical use.

  However, in recent years, semiconductor elements have been increasingly miniaturized, and today, mass production of VLSI using a quarter micron (0.25 μm or less) ultrafine pattern is about to begin. In order to obtain such an ultrafine pattern of quarter micron, it is difficult to use conventional photoresists containing alkali-soluble novolac resin and quinonediazide group-containing compound as basic components. Development of resists using excimer lasers such as KrF and ArF, electron beams and X-rays has been demanded. As such a resist, in addition to achieving high resolution, a chemically amplified resist that can use a catalytic reaction and a chain reaction of an acid generated by irradiation of radiation and has a quantum yield of 1 or more and can achieve high sensitivity is attracting attention. It has been actively developed.

  As the chemically amplified resist, for example, a resist composition in which a resin component in which a hydroxyl group of polyhydroxystyrene is substituted with a tert-butoxycarbonyloxy group and an acid generator such as an onium salt has been proposed (Patent Document 1 below) reference).

US Pat. No. 4,491,628

  However, the above resist composition is not sufficient in resolution and depth of focus characteristics, and when it is developed after being allowed to stand for a certain time after exposure, it causes the deactivation of the acid generated by exposure specific to the chemically amplified resist. There is a problem of pattern shape deterioration due to this (hereinafter referred to as “retention stability”), that is, a bridging problem in which the upper part of the resist pattern is connected in a hook shape. If such bridging can be performed, a desired wiring pattern cannot be obtained, which is fatal in semiconductor device manufacturing. As a method for solving such a problem with aging, there is a method of providing a topcoat layer on the resist layer in order to prevent the deactivation of acid generated by exposure. However, such a method increases the number of manufacturing steps. This is not preferable because the throughput is deteriorated and the cost is increased. Therefore, the emergence of a resist having excellent placement stability that does not require the topcoat layer is strongly desired.

  Further, the chemically amplified resist has a skirt pattern shape with respect to a substrate provided with an insulating film such as a silicon nitride film (SiN) or boron-phosphorus-silicate glass (BPSG) or a titanium nitride (TiN) film. There is a problem (hereinafter referred to as substrate dependency). It is presumed that the amine remains in the vicinity of the substrate when the film is formed, and thereby the acid generated by exposure is deactivated, resulting in a tailing shape.

  Furthermore, when a substrate provided with a metal film such as an aluminum-silicon-copper (Al-Si-Cu) alloy or tungsten (W) is used, there is a problem that the pattern cross-sectional shape becomes a waveform due to the influence of standing waves. . As a method of solving these problems of substrate dependency and standing wave, there is a method of providing an antireflection layer between the substrate and the resist layer. This is not preferable because the increased throughput and the cost are increased. Therefore, there is a strong demand for a resist that can form a resist pattern having an excellent profile shape that does not depend on the substrate, does not require an antireflection layer, and is not easily affected by standing waves.

  In addition to the above problems, the conventional resist composition has a problem in that when it is used as a solution, it often lacks storage stability, for example, foreign matter is generated during storage. Therefore, there is also a demand for a resist composition that can provide a resist solution that is free from the foreign matter and has excellent storage stability.

  The present invention has been made in view of the above circumstances, and is excellent in light transmittance with respect to radiation, particularly excimer laser light such as deep-UV, KrF, and ArF, and has high sensitivity, high resolution, heat resistance, It is an object of the present invention to provide a resist acid generator suitable for use in the realization of a positive resist composition having excellent depth of focus characteristics, stability over time, and storage stability of a resist solution.

  Another object of the present invention is to provide a resist acid generator suitable for use in the realization of a positive resist composition that can form a resist pattern having no substrate dependency and having an excellent profile shape.

  In view of such a current situation, the present inventors have conducted extensive research, and as a result, used a resin component whose solubility in an alkaline aqueous solution is increased by the action of an acid, and a compound that generates an acid upon irradiation with radiation. Incorporating an organic carboxylic acid compound into this product provides high sensitivity, high resolution, heat resistance, stability over time, excellent depth of focus characteristics and storage stability of the resist solution, and has no substrate dependence and profile. Chemically amplified positive type that is sensitive to radiation such as excimer lasers such as ultraviolet rays, far ultraviolet rays, KrF, ArF, X-rays, and electron beams that can form resist patterns with excellent shapes. It has been found that a resist composition can be obtained, and bis (cyclohexylsulfonyl) diazomethane is used as the acid generating compound. Using bis (2,4-dimethyl-phenylsulfonyl) mixture of diazomethane leads to findings that it is possible to achieve a further higher sensitivity, and completed the present invention.

  The present invention has been made based on the above findings, and the resist acid generator according to the present invention comprises a mixture of bis (cyclohexylsulfonyl) diazomethane and bis (2,4-dimethylphenylsulfonyl) diazomethane. It is an acid generator for resists. The resist acid generator according to the present invention comprises (A) a positive resist composition comprising a resin component whose solubility in an alkaline aqueous solution is increased by the action of an acid, and (B) a compound that generates an acid upon irradiation with radiation. Can be suitably used as the component (B), and the sensitivity of the positive resist composition can be greatly improved.

（式中、Ｒ¹は水素原子又はメチル基であり、Ｒ²はメチル基又はエチル基であり、Ｒ³は炭素数１〜４の低級アルキル基である）で表わされる残基で置換された重量平均分子量８，０００〜２２，０００のポリヒドロキシスチレンであるか、（ｂ）水酸基の１０〜６０モル％がｔｅｒｔ−ブトキシカルボニルオキシ基で置換された重量平均分子量８，０００〜２２，０００のポリヒドロキシスチレンであるか、あるいは、前記（ａ）成分と（ｂ）成分との混合物であることを特徴とする。 The component (A) in the positive resist composition comprises (a) 10 to 60 mol% of the hydroxyl group represented by the following general formula (1):

(Wherein R ¹ is a hydrogen atom or a methyl group, R ² is a methyl group or an ethyl group, and R ³ is a lower alkyl group having 1 to 4 carbon atoms). A polyhydroxystyrene having a weight average molecular weight of 8,000 to 22,000, or (b) having a weight average molecular weight of 8,000 to 22,000 in which 10 to 60 mol% of the hydroxyl groups are substituted with a tert-butoxycarbonyloxy group. It is polyhydroxystyrene or a mixture of the component (a) and the component (b).

  The positive resist composition preferably further includes (C) an organic carboxylic acid compound. The component (C) is preferably at least one selected from the group consisting of aromatic carboxylic acids, alicyclic carboxylic acids, and unsaturated aliphatic carboxylic acids. Moreover, it is preferable that the said (C) component contains 0.01 to 1 weight% with respect to the total amount of the said (A) component and the said (B) component.

［式中、Ｒ⁴及びＲ⁵はそれぞれ独立して水素原子、水酸基、ニトロ基、カルボキシル基、ビニル基を表す（ただし，Ｒ⁴及びＲ⁵が共に水素原子の場合は除く。）］で表される化合物である。 The aromatic carboxylic acid compound has the following general formula (2)

[Wherein, R ⁴ and R ⁵ each independently represent a hydrogen atom, a hydroxyl group, a nitro group, a carboxyl group, or a vinyl group (provided that R ⁴ and R ⁵ are both hydrogen atoms)]. It is a compound.

（式中、ｎは０又は１〜１０の整数を示す）で表される化合物である。 The aromatic carboxylic acid compound is represented by the following general formula (3):

(Wherein n represents 0 or an integer of 1 to 10).

  The alicyclic carboxylic acid comprises 1,1-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, and 1,1-cyclohexyldiacetic acid. It is preferably at least one selected from the group.

  The unsaturated aliphatic carboxylic acid compound includes acrylic acid, crotonic acid, isocrotonic acid, 3-butenoic acid, methacrylic acid, 4-pentenoic acid, propiolic acid, 2-butynoic acid, maleic acid, fumaric acid, and acetylenecarboxylic acid. It is preferably at least one selected from the group consisting of

  The positive resist composition may further contain a light absorber, and the light absorber is preferably benzophenone.

  When the acid generator for resists according to the present invention is used in a resist composition, the sensitivity can be increased particularly. For example, the positive resist composition using the acid generator for resists of the present invention has very high sensitivity, high resolution of quarter micron or less, heat resistance, depth of focus characteristics, attractiveness. It is a resist composition that is excellent in stability over time, can form a resist pattern with no substrate dependency, and has an excellent profile shape, and can be sufficiently applied to a semiconductor device manufacturing process that requires a quarter micron resolution. Furthermore, since a semiconductor element can be manufactured with a single layer without providing a topcoat layer or an antireflection layer that increases the manufacturing process, the cost is low and the effect is extremely large and practical.

Hereinafter, embodiments of the present invention will be described.
The acid generator for a resist according to the present invention is characterized by containing a mixture of bis (cyclohexylsulfonyl) diazomethane and bis (2,4-dimethylphenylsulfonyl) diazomethane. When used in a positive resist composition containing a resin component whose solubility in an alkaline aqueous solution increases by action and (B) a compound that generates an acid upon irradiation with radiation, the sensitivity of the resist composition is greatly improved. Can do.

  In the positive resist composition using the resist acid generator of the present invention as the component (B), a mixture of the component (B) bis (cyclohexylsulfonyl) diazomethane and bis (2,4-dimethylphenylsulfonyl) diazomethane. The acid generated from the acid generator is decomposing the tert-butoxycarbonyloxy group and the residue represented by the general formula (1) in the polyhydroxystyrene which is the resin component, and thereby in the exposed portion of the resin component. It is possible to achieve a high balance between the solubility in alkali and the dissolution inhibiting ability in the unexposed area, achieve high sensitivity, high resolution, and high heat resistance, and improve the depth of focus characteristics.

  The resist acid generator comprising a mixture of bis (cyclohexylsulfonyl) diazomethane and bis (2,4-dimethylphenylsulfonyl) diazomethane according to the present invention is particularly suitable for exposure of resin components when excimer laser light is used for exposure. It is possible to achieve a high balance between the solubility in alkali in the part and the dissolution inhibiting ability in the unexposed part, achieving high sensitivity, high resolution and high heat resistance, and improving the depth of focus characteristics. it can.

  When the resist acid generator of the present invention is used in the positive resist composition, the proportion of the resist acid generator of the present invention is 1 to 20 parts by weight, preferably 2 to 10 parts per 100 parts by weight of the resin component. It is the ratio of parts by weight. When the amount of the acid generator is less than 1 part by weight, the effect is insufficient. When the amount exceeds 20 parts by weight, the acid generator is not completely dissolved in the solvent and the miscibility with the resin component is deteriorated.

  In the positive resist composition, the resin component whose solubility in an alkaline aqueous solution is increased by the action of the acid as the component (A) is (a) 10-60 mol% of the hydroxyl group is represented by the following general formula (1).

(Wherein R ¹ is a hydrogen atom or a methyl group, R ² is a methyl group or an ethyl group, and R ³ is a lower alkyl group having 1 to 4 carbon atoms). A polyhydroxystyrene having a weight average molecular weight of 8,000 to 22,000, or (b) having a weight average molecular weight of 8,000 to 22,000 in which 10 to 60 mol% of the hydroxyl groups are substituted with a tert-butoxycarbonyloxy group. It is preferably polyhydroxystyrene or a mixture of the component (a) and the component (b).

  In the component (a), the hydroxyl group of polyhydroxystyrene is substituted with the residue of the general formula (1) according to a known substitution reaction with 1-chloro-1-ethoxyethane or 1-chloro-1-methoxypropane, for example. The substitution rate is 10 to 60 mol%, preferably 20 to 50 mol%. If the substitution rate is less than 10 mol%, a pattern having an excellent shape cannot be obtained. If the substitution rate exceeds 60 mol%, the sensitivity of the resist is lowered, which is not preferable. In practice, 20 to 50 mol% is effective.

  On the other hand, the component (b) is obtained by substituting the hydroxyl group of polyhydroxystyrene with a tert-butoxycarbonyloxy group according to a known substitution reaction, for example, with di-tert-butyl-di-carbonate or the like. The range of 10 to 60 mol%, preferably 20 to 50 mol% is preferable. If this substitution rate is less than 10 mol%, a resist pattern having an excellent profile shape cannot be obtained, and if it exceeds 60 mol%, the sensitivity decreases, which is not preferred. In practice, 20-50 mol% is effective.

  The weight average molecular weight of each resin component is in the range of 8,000 to 22,000 based on polystyrene based on the gel permeation chromatography method (GPC method). When the weight average molecular weight is less than the above range, the film property is not good, and when it exceeds the upper limit range, the solubility in an alkaline aqueous solution is poor. Further, the resin component of the present invention preferably has a molecular weight distribution (Mw / Mn) in the range of 3 to 5 represented by the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn). When the weight average molecular weight and molecular weight distribution are in the above ranges, the depth of focus characteristics and the storage stability of the resist solution are improved.

  In the above structure, the resist acid generator of the present invention suitable for the compound that generates an acid upon irradiation with radiation as the component (B) is bis (cyclohexylsulfonyl) diazomethane and bis (2,4-dimethylphenylsulfonyl). This is a mixture with diazomethane, whereby the sensitivity of the positive resist composition can be increased. The acid generator for resists of the present invention may further contain a conventionally known acid generator in addition to the mixture.

  In the positive resist composition, by adding an organic carboxylic acid compound as component (C), it is possible to form a resist pattern with excellent sensitivity and resolution and a good cross-sectional shape, and stable over time after exposure. It becomes the resist composition which is excellent also in property. Furthermore, resist patterns having good cross-sectional shapes can be obtained for various substrates.

  As the organic carboxylic acid compound used in the positive resist composition, any of saturated or unsaturated aliphatic carboxylic acid, alicyclic carboxylic acid, oxycarboxylic acid, alkoxycarboxylic acid, ketocarboxylic acid, aromatic carboxylic acid and the like are used. It is not particularly limited, and examples thereof include monovalent or polyvalent aliphatic carboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, and adipic acid. 1,1-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,1-cyclohexyldiacetic acid and other alicyclic carboxylic acids, acrylic acid , Crotonic acid, isocrotonic acid, 3-butenoic acid, methacrylic acid, 4-pentenoic acid, propiolic acid 2-butynoic acid, maleic acid, fumaric acid, unsaturated aliphatic carboxylic acid such as acetylene carboxylic acid, oxycarboxylic acid such as oxyacetic acid, alkoxycarboxylic acid such as methoxyacetic acid and ethoxyacetic acid, ketocarboxylic acid such as pyruvic acid and the following General formula (2)

（式中、Ｒ⁴及びＲ⁵はそれぞれ独立して水素原子、水酸基、ニトロ基、カルボキシル基、ビニル基を表す［ただし、Ｒ⁴及びＲ⁵が共に水素原子の場合は除く。］）及び下記一般式（３）

(Wherein, R ⁴ and R ⁵ each independently represent a hydrogen atom, a hydroxyl group, a nitro group, a carboxyl group, or a vinyl group [provided that R ⁴ and R ⁵ are both hydrogen atoms]) and the following: General formula (3)

（式中、ｎは０又は１〜１０の整数を示す）で表される芳香族カルボン酸などを挙げることができるが、脂環式カルボン酸、不飽和脂肪族カルボン酸、及び芳香族カルボン酸が好ましく使用される。

(In the formula, n represents 0 or an integer of 1 to 10) and the like, and examples thereof include alicyclic carboxylic acids, unsaturated aliphatic carboxylic acids, and aromatic carboxylic acids. Are preferably used.

  Examples of the aromatic carboxylic acid represented by the general formula (2) include p-hydroxybenzoic acid, o-hydroxybenzoic acid, 2-hydroxy-3-nitrobenzoic acid, 3,5-dinitrobenzoic acid, 2- Nitrobenzoic acid, 2,4-dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid, 3,4-dihydroxybenzoic acid, 3,5-dihydroxybenzoic acid, 2-vinylbenzoic acid, 4-vinylbenzoic acid, phthalic acid, terephthalic acid, isophthalic acid and the like can be mentioned, and in particular, benzoic acid having a substituent at the o-position, such as o-hydroxybenzoic acid, o-nitrobenzoic acid, phthalic acid and the like. Is preferred.

  In addition, as the aromatic carboxylic acid compound represented by the general formula (3), it can be used even when n in the formula is a single compound or a combination of different compounds. Commercially available SAX (trade name, manufactured by Mitsui Toatsu Chemical Co., Ltd.) is preferably used as the compound.

  The aromatic carboxylic acid compounds represented by the general formulas (2) and (3) may be used alone or in admixture of two or more. By blending these aromatic carboxylic acid compounds, it is possible to form a resist pattern with a good cross-sectional shape, and excellent stability over time after exposure, and the length of time until heat treatment applied after exposure. Regardless, a favorable profile shape can be formed. In particular, the aromatic carboxylic acid compound represented by the general formula (3) is preferable because a rectangular cross-sectional shape can be formed.

  The amount of the organic carboxylic acid compound used in the positive resist composition is 0.01 to 1% by weight, preferably 0.05, based on the total amount of the resin component and the acid generator according to the present invention. Used in the range of ˜0.5% by weight. If the amount of the organic carboxylic acid compound is less than 0.01% by weight, a resist pattern having a good cross-sectional shape cannot be obtained, and if it exceeds 1% by weight, the developability deteriorates, which is not preferable.

  In addition to the resin component, acid generator and organic carboxylic acid compound, the positive resist composition preferably contains a light absorber in order to improve sensitivity and resolution. Examples of the light absorber include 1- [1- (4-hydroxyphenyl) isopropyl] -4- [1,1-bis (4-hydroxyphenyl) ethyl] benzene, bis (4-hydroxy-3,5-dimethyl). Naphthoquinone-1,2-diazide-5-sulfonic acid ester of polyphenols such as phenyl) -3,4-dihydroxyphenylmethane, and benzophenone, and sensitivity and resolution can be obtained by blending these light-absorbing agents. It can be preferably used because it has an effect of improving the above-mentioned improvement and suppresses the influence of the standing wave and has a function of forming a rectangular resist pattern without the cross-sectional shape being wavy. The blending amount of the light absorber is blended within a range not exceeding 30% by weight with respect to the total amount of (A) the resin component and (B) the acid generator using the acid generator of the present invention, and preferably Is blended in the range of 0.5 to 15% by weight. If the blending amount exceeds 30% by weight, the profile shape is deteriorated, which is not preferable.

  The positive resist composition is preferably used in the form of a solution in which the above components are dissolved in a solvent. Examples of such solvents include ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl isoamyl ketone, 2-heptanone; ethylene glycol, ethylene glycol monoacetate, diethylene glycol, diethylene glycol monoacetate, propylene glycol, propylene glycol monoacetate, diester Polyhydric alcohols such as propylene glycol or dipropylene glycol monoacetate monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether or monophenyl ether and derivatives thereof; cyclic ethers such as dioxane; and methyl lactate, lactic acid Ethyl, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate It can be mentioned esters such as ethyl ethoxypropionate. These may be used alone or in combination of two or more.

  In the positive resist composition of the present invention, if desired, conventional additives such as miscible additives, for example, additional resins, plasticizers, stabilizers, colorants, surfactants, etc. for improving the performance of the resist film are used. What has been added can be added.

  For example, a silicon nitride film (SiN), a substrate provided with an insulating film such as BPSG, titanium nitride (TiN), Al—Si—Cu, by dissolving the positive resist composition in a solvent and using a spinner or the like. It is applied to a substrate or the like provided with a metal film such as tungsten and dried to form a photosensitive layer, and then irradiated with deep-UV light and excimer laser light through a desired mask pattern by a reduction projection exposure apparatus or the like. Or by drawing with an electron beam and developing with a developing solution, for example, a weak alkaline aqueous solution such as an aqueous solution of 1 to 10% by weight of tetramethylammonium hydroxide, a good resist pattern faithful to the mask pattern is formed on various substrates. Formed without dependence.

  Next, the present invention will be described in more detail with reference to production examples, reference examples, and examples, but the present invention is not limited to these examples.

Production Example 1
(Synthesis of polyhydroxystyrene in which 8 mol% of hydroxyl group is substituted with tert-butoxycarbonyloxy group)
120 g of polyhydroxystyrene having a weight average molecular weight of 20,000 and a molecular weight distribution (Mw / Mn) of 4.0 was dissolved in 680 g of N, N-dimethylacetamide, and di-tert-butyl-dicarbonate 17. After 4 g was added and stirred to dissolve completely, 59 g of triethylamine was added dropwise over about 15 minutes with stirring. After completion of dropping, the mixture was stirred as it was for about 3 hours. Next, 20 times the amount of pure water was added to the resulting solution and stirred to precipitate polyhydroxystyrene in which the hydroxyl group was substituted with a tert-butoxycarbonyloxy group. The precipitate was washed with pure water, dehydrated and dried, and polyhydroxystyrene in which 8 mol% of the hydroxyl group was substituted with a tert-butoxycarbonyloxy group (weight average molecular weight 20,000, molecular weight distribution (Mw / Mn) 4 0.0) 125 g was obtained.

Production Example 2
(Synthesis of polyhydroxystyrene in which 35 mol% of hydroxyl groups are substituted with tert-butoxycarbonyloxy groups)
In Production Example 1, 35 mol% of the hydroxyl group was replaced with a tert-butoxycarbonyloxy group in the same manner as in Production Example 1, except that the addition amount of di-tert-butyl-dicarbonate was changed to 76.5 g. 145 g of polyhydroxystyrene (weight average molecular weight 20,000, molecular weight distribution (Mw / Mn) 4.0) was obtained.

Production Example 3
(Synthesis of polyhydroxystyrene in which 39 mol% of hydroxyl groups are substituted with tert-butoxycarbonyloxy groups)
39% by mole of the hydroxyl group was replaced with a tert-butoxycarbonyloxy group in the same manner as in Production Example 1 except that the amount of di-tert-butyl-dicarbonate added in Production Example 1 was changed to 85.0 g. 150 g of polyhydroxystyrene (weight average molecular weight 20,000, molecular weight distribution (Mw / Mn) 4.0) was obtained.

Production Example 4
(Synthesis of polyhydroxystyrene in which 70 mol% of hydroxyl groups are substituted with tert-butoxycarbonyloxy groups)
In the same manner as in Production Example 1 except that the amount of di-tert-butyl-dicarbonate added in the production example 1 was changed to 153 g, a polyhydroxy compound in which 70 mol% of the hydroxyl groups were substituted with tert-butoxycarbonyloxy groups was used. 180 g of hydroxystyrene (weight average molecular weight 20,000, molecular weight distribution (Mw / Mn) 4.0) was obtained.

Production Example 5
(Synthesis of polyhydroxystyrene in which 35 mol% of hydroxyl groups are substituted with ethoxyethoxy groups)
120 g of polyhydroxystyrene having a weight average molecular weight of 20,000 and a molecular weight distribution (Mw / Mn) of 4.0 is dissolved in 680 g of N, N-dimethylacetamide, and 37.2 g of 1-chloro-1-ethoxyethane is dissolved in this solution. After stirring, the mixture was completely dissolved, and 78.8 g of triethylamine was added dropwise over about 30 minutes while stirring. After completion of dropping, the mixture was stirred as it was for about 3 hours. Next, 20 times the amount of pure water was added to the resulting solution, and the mixture was stirred to obtain polyhydroxystyrene in which 35 mol% of the hydroxyl group was substituted with 1-ethoxyethoxy group (weight average molecular weight 20,000, molecular weight distribution (Mw / Mn) 4.0) 130 g.

Production Example 6
(Synthesis of polyhydroxystyrene in which 8 mol% of hydroxyl groups are substituted with methoxy-n-propyloxy groups)
120 g of polyhydroxystyrene having a weight average molecular weight of 20,000 and a molecular weight distribution (Mw / Mn) of 4.0 is dissolved in 680 g of N, N-dimethylacetamide, and 8.6 g of 1-chloro-1-methoxypropane is dissolved in this solution. After stirring, the mixture was completely dissolved, and 78.8 g of triethylamine was added dropwise over about 30 minutes while stirring. After completion of dropping, the mixture was stirred as it was for about 3 hours. Next, 20 times the amount of pure water was added to the resulting solution and stirred to precipitate polyhydroxystyrene in which the hydroxyl group was substituted with 1-methoxy-n-propyloxy group. The precipitate was washed, dehydrated and dried, and polyhydroxystyrene in which 8 mol% of the hydroxyl group was substituted with 1-methoxy-n-propyloxy group (weight average molecular weight 20,000, molecular weight distribution (Mw / Mn) 4 0.0) 125 g was obtained.

Production Example 7
(Synthesis of polyhydroxystyrene in which 39 mol% of hydroxyl groups are substituted with methoxy-n-propyloxy groups)
In Production Example 6, except that the amount of 1-chloro-1-methoxypropane added was changed to 42.3 g, 39 mol% of the hydroxyl group was replaced with 1-methoxy-n-propyloxy group in the same manner as in Production Example 6. 130 g of polyhydroxystyrene (weight average molecular weight 20,000, molecular weight distribution (Mw / Mn) 4.0) was obtained.

Production Example 8
(Synthesis of polyhydroxystyrene in which 70 mol% of hydroxyl groups are substituted with methoxy-n-propyloxy groups)
In Production Example 6, 70 mol% of the hydroxyl group was replaced with 1-methoxy-n-propyloxy group in the same manner as in Production Example 6 except that the addition amount of 1-chloro-1-methoxypropane was changed to 75.6 g. 150 g of the resulting polyhydroxystyrene (weight average molecular weight 20,000, molecular weight distribution (Mw / Mn) 4.0) was obtained.

Reference example 1
1.48 g of polyhydroxystyrene (weight average molecular weight 20,000, molecular weight distribution (Mw / Mn) 4.0) obtained by substituting 35 mol% of the hydroxyl group obtained in Production Example 2 with a tert-butoxycarbonyloxy group 1. Polyhydroxystyrene (35 weight% of the hydroxyl group obtained in 5) substituted with ethoxyethoxy group (weight average molecular weight 20,000, molecular weight distribution (Mw / Mn) 4.0) 1.48 g was added to propylene glycol monomethyl ether acetate 16. After dissolving in 8 g, 0.148 g of bis (cyclohexylsulfonyl) diazomethane, 0.093 g of benzophenone and 0.0032 g of o-hydroxybenzoic acid were further added and dissolved, and the resulting solution was filtered with a membrane filter having a pore size of 0.2 μm. This was prepared as a positive resist coating solution.

The prepared coating solution was applied onto a 6-inch silicon wafer using a spinner and dried at 90 ° C. for 90 seconds on a hot plate to obtain a resist film having a thickness of 0.7 μm. The film was exposed to an excimer laser through a test chart mask using a reduction projection exposure apparatus NSR-2005EX8A (manufactured by Nikon Corporation), heated at 120 ° C. for 90 seconds, and then 2.38 wt% tetramethylammonium hydroxide. Paddle development was performed with an aqueous solution for 65 seconds, followed by washing with water and drying for 30 seconds to form a resist pattern. The cross section of the formed resist pattern was slightly rounded at the top, but it was not affected by standing waves and was close to a rectangle, and a 0.21 μm line and space pattern was formed. Further, the minimum exposure amount (hereinafter referred to as the minimum exposure amount) at which the resist pattern having a large area that can be visually confirmed was patterned and the substrate surface appeared was measured and found to be 7 mJ / cm ² . Furthermore, as a result of examining the heat resistance (temperature at which heat flow occurs) of the formed 0.5 μm line pattern, it was 130 ° C. The maximum focal length (μm) at which a 0.25 μm line-and-space pattern with a focal depth of 1: 1 is formed is 1.0 μm or more as A, and less than 1.0 μm is evaluated as B. It was. When this resist solution was stored in a brown bottle at 25 ° C. and the storage stability was examined, no foreign matter was generated for 6 months.

  In addition, a resist pattern was formed in the same manner as described above except that it was left to stand for 15 minutes and then heat-treated at 120 ° C. for 90 seconds after the exposure process. A 0.21 μm line and space pattern was formed.

Reference example 2
In the preparation of the coating solution of Reference Example 1, a resist pattern was formed by the same operation as Reference Example 1 except that benzophenone was removed. The cross section of the formed resist pattern is slightly rounded at the top and has a wave but no problem, and it is close to a rectangle. A 0.23 μm line and space pattern was formed. . Moreover, it was 8 mJ / cm < ² > as a result of measuring minimum exposure amount. Furthermore, as a result of examining the heat resistance of the formed 0.5 μm line pattern, it was 130 ° C. When the depth of focus was evaluated in the same manner as in Reference Example 1, it was A. Furthermore, as a result of examining the storage stability of the resist solution, no foreign matter was generated for 6 months.

  In addition, a resist pattern was formed in the same manner as in Reference Example 1 except that after the exposure process, the sample was left for 15 minutes and then subjected to a heat treatment at 120 ° C. for 90 seconds. A 23 μm line and space pattern was formed.

Reference example 3
In the preparation of the coating solution of Reference Example 1, Reference Example 1 was used except that 0.0062 g of SAX (trade name, manufactured by Mitsui Toatsu Chemical Co., Ltd.) marketed as a phenol compound was added instead of o-hydroxybenzoic acid. A resist pattern was formed by the same operation. The cross section of the formed resist pattern was free from the influence of standing waves and had a good rectangular shape, and a 0.21 μm line and space pattern was formed. Moreover, it was 7 mJ / cm < ² > as a result of measuring minimum exposure amount. Furthermore, as a result of examining the heat resistance of the formed 0.5 μm line pattern, it was 130 ° C. When the depth of focus was evaluated in the same manner as in Reference Example 1, it was A. Furthermore, as a result of examining the storage stability of the resist solution, no foreign matter was generated for 6 months.

  In addition, a resist pattern was formed in the same manner as in Reference Example 1 except that after performing the exposure process, the film was allowed to stand for 15 minutes and then subjected to a heat treatment at 120 ° C. for 90 seconds. A 0.21 μm line-and-space pattern having a good rectangular profile shape was formed.

Reference example 4
In the preparation of the coating solution of Reference Example 1, a resist pattern was formed by the same operation as Reference Example 1 except that 0.0062 g of acrylic acid was added instead of o-hydroxybenzoic acid. The cross section of the formed resist pattern was free from the influence of standing waves and had a good rectangular shape, and a 0.21 μm line and space pattern was formed. Moreover, it was 7 mJ / cm < ² > as a result of measuring minimum exposure amount. Furthermore, as a result of examining the heat resistance of the formed 0.5 μm line pattern, it was 130 ° C. When the depth of focus was evaluated in the same manner as in Reference Example 1, it was A. Furthermore, as a result of examining the storage stability of the resist solution, no foreign matter was generated for 6 months.

  In addition, a resist pattern was formed in the same manner as in Reference Example 1 except that after the exposure treatment, the sample was left for 15 minutes and then subjected to a heat treatment at 120 ° C. for 90 seconds. A profile-shaped 0.21 μm line and space pattern was formed.

Reference Example 5
Polyhydroxystyrene (weight average molecular weight 20,000, molecular weight distribution (Mw / Mn) 4.0) 1.05 g in which 39 mol% of the hydroxyl group obtained in Production Example 3 was substituted with a tert-butoxycarbonyloxy group, and Production Example Polyethylene styrene (weight average molecular weight 20,000, molecular weight distribution (Mw / Mn) 4.0) in which 39 mol% of the hydroxyl group obtained in 7 was substituted with 1-methoxy-n-propyloxy group was propylene. After dissolving in 16.8 g of glycol monomethyl ether acetate, 0.21 g of bis (cyclohexylsulfonyl) diazomethane and 0.009 g of o-nitrobenzoic acid are further added, and the resulting solution is dissolved in a membrane filter having a pore size of 0.2 μm. And prepared as a positive resist coating solution.

The prepared coating solution was applied onto a 6-inch silicon wafer using a spinner, and dried on a hot plate at 90 ° C. for 90 seconds to obtain a resist film having a thickness of 0.7 μm. The film was exposed through a test chart mask using a reduced projection exposure apparatus NSR-2005EX8A (manufactured by Nikon Corporation), heated at 110 ° C. for 90 seconds, and then heated with a 2.38 wt% tetramethylammonium hydroxide aqueous solution. When a paddle development was performed for 2 seconds, washed with water for 30 seconds, and then dried to form a resist pattern, a 0.22 μm line and space pattern was formed. The resist pattern cross section had a slight wave, but had no problem, and was a good rectangle. Moreover, it was 15 mJ / cm < ² > as a result of measuring minimum exposure amount. Furthermore, as a result of examining the heat resistance of the formed 0.5 μm line pattern, it was 130 ° C. When the depth of focus was evaluated in the same manner as in Reference Example 1, it was A. Furthermore, as a result of examining the storage stability of the resist solution, no foreign matter was generated for 6 months.

Reference Example 6
In the preparation of the coating solution of Reference Example 5, o-nitrobenzoic acid was replaced with SAX (trade name, manufactured by Mitsui Toatsu Chemical Co., Ltd.), and 0.128 g of benzophenone was further added. When the resist characteristics were evaluated, a 0.22 μm line and space pattern was formed, and the cross section of the resist pattern was rectangular and good without being affected by standing waves. Moreover, it was 13 mJ / cm < ² > as a result of measuring minimum exposure amount. Furthermore, as a result of examining the heat resistance of the formed 0.5 μm line pattern, it was 130 ° C. When the depth of focus was evaluated in the same manner as in Reference Example 1, it was A. Furthermore, as a result of examining the storage stability of the resist solution, no foreign matter was generated for 6 months.

Reference Example 7
In the preparation of the coating solution of Reference Example 5, coating was performed in the same manner as in Reference Example 5 except that o-nitrobenzoic acid was replaced with salicylic acid, the amount added was changed to 0.003 g, and benzophenone 0.128 g was further added. A liquid was prepared.

Next, evaluation of resist characteristics similar to that of Reference Example 5 was performed. As a result, a 0.22 μm line and space pattern was formed, and the resist pattern cross-section was slightly rounded at the top, but was affected by standing waves. It was a good one close to a rectangle. Further, the minimum exposure amount was 7 mJ / cm ² . Furthermore, as a result of examining the heat resistance of the formed 0.5 μm line pattern, it was 130 ° C. When the depth of focus was evaluated in the same manner as in Reference Example 1, it was A. Furthermore, as a result of examining the storage stability of the resist solution, no foreign matter was generated for 6 months.

Reference Example 8
A coating solution was prepared in the same manner as in Reference Example 5 except that o-nitrobenzoic acid was replaced by 0.009 g of 1,1-cyclohexanedicarboxylic acid in the preparation of the coating solution of Reference Example 5.

Next, the same resist characteristics as in Reference Example 5 were evaluated. As a result, a 0.21 μm line-and-space pattern was formed, and the resist pattern cross-section had a slight wave but no problem. The rectangle was good. Moreover, it was 13 mJ / cm < ² > as a result of measuring minimum exposure amount. It was 130 degreeC as a result of investigating the heat resistance of the formed 0.5 micrometer line pattern. When the depth of focus was evaluated in the same manner as in Reference Example 1, it was A. Furthermore, as a result of examining the storage stability of the resist solution, no foreign matter was generated for 6 months. Furthermore, a resist pattern was formed in the same manner as described above except that it was left to stand for 30 minutes and then heat-treated at 110 ° C. for 90 seconds after the exposure process. A 0.21 μm line and space pattern was formed.

Reference Example 9
In the preparation of the coating solution of Reference Example 8, a positive resist coating solution was prepared in the same manner as in Reference Example 8 except that 0.12 g of benzophenone was further added.

Next, when the resist characteristics were evaluated in the same manner as in Reference Example 8, a 0.21 μm line and space pattern was formed, and the resist pattern cross section was rectangular and good without being affected by standing waves. . Further, the minimum exposure amount was 13 mJ / cm ² . Furthermore, as a result of examining the heat resistance of the formed 0.5 μm line pattern, it was 130 ° C. When the depth of focus was evaluated in the same manner as in Reference Example 1, it was A. Furthermore, as a result of examining the storage stability of the resist solution, no foreign matter was generated for 6 months.

  In addition, after the exposure process, the film was left to stand for 30 minutes and then heated at 110 ° C. for 90 seconds to form a 0.21 μm line-and-space pattern with a vertical profile and a good profile shape. It was.

Comparative Example 1
After dissolving 2.96 g of polyhydroxystyrene in which 35 mol% of the hydroxyl group obtained in Production Example 2 is substituted with tert-butoxycarbonyloxy group in 16.8 g of propylene glycol monomethyl ether acetate, triphenylsulfonium hexafluoroantimonate is dissolved. A solution obtained by adding 0.09 g and dissolving was filtered through a 0.2 μm membrane filter to prepare a positive resist coating solution.

Using the prepared coating solution, a resist pattern was formed on the silicon wafer by the same operation as in Reference Example 1. However, the line and space pattern of 0.30 μm was the limit, and the resist pattern cross section had a bowl-shaped defect. It was something. Moreover, it was 10 mJ / cm < ² > as a result of measuring minimum exposure amount. Further, when the heat resistance of the formed 0.5 μm line pattern was examined, it was 140 ° C. When the depth of focus was evaluated in the same manner as in Reference Example 1, it was B.

  After performing the above exposure processing, the resist pattern shape after standing for 15 minutes and then performing heat treatment at 120 ° C. for 90 seconds is a T-top shape, and the 0.5 μm line and space pattern is the limit. It was.

Comparative Example 2
After dissolving 2.96 g of polyhydroxystyrene in which 35 mol% of the hydroxyl group obtained in Production Example 5 is substituted with ethoxyethoxy group in 16.8 g of propylene glycol monomethyl ether acetate, 0.148 g of bis (cyclohexylsulfonyl) diazomethane and A solution obtained by further adding 0.093 g of benzophenone and dissolving it was filtered through a 0.2 μm membrane filter to prepare a positive resist coating solution.

When the resist pattern was formed by the same operation as in Reference Example 1 using the prepared coating solution, the line-and-space pattern of 0.25 μm was the limit, and the resist pattern cross section was inferior in an inverted triangle shape. there were. Moreover, it was 7 mJ / cm < ² > as a result of measuring minimum exposure amount. Further, when the heat resistance of the formed 0.5 μm line pattern was examined, it was 120 ° C.

Comparative Example 3
1.05 g of polyhydroxystyrene in which 8% of the hydroxyl groups obtained in Production Example 1 were substituted with tert-butoxycarbonyloxy groups and 8% of the hydroxyl groups obtained in Production Example 6 were substituted with methoxy-n-propyloxy groups After dissolving 1.95 g of the polyhydroxystyrene dissolved in 16.8 g of propylene glycol monomethyl ether acetate, 0.21 g of bis (cyclohexylsulfonyl) diazomethane, 0.009 g of o-nitrobenzoic acid, and 0.128 g of benzophenone were further added. The solution obtained by dissolution was filtered through a 0.2 μm membrane filter to prepare a positive resist coating solution.

  Although the resist characteristics similar to those of Reference Example 5 were evaluated for the coating solution, a resist pattern was not obtained and evaluation was impossible.

Comparative Example 4
1.48 g of polyhydroxystyrene (weight average molecular weight 20,000) in which 35 mol% of the hydroxyl group obtained in Production Example 2 is substituted with a tert-butoxycarbonyloxy group and 35 mol% of the hydroxyl group obtained in Production Example 5 After dissolving 1.48 g of polyhydroxystyrene substituted with ethoxyethoxy group (weight average molecular weight 20,000) in 16.8 g of propylene glycol monomethyl ether acetate, 0.148 g of bis (cyclohexylsulfonyl) diazomethane and 0.093 g of benzophenone The solution obtained by further adding and dissolving was filtered through a 0.2 μm membrane filter to prepare a coating solution.

The prepared coating solution was applied onto a 6-inch silicon wafer using a spinner, and dried on a hot plate at 90 ° C. for 90 seconds to obtain a resist film having a thickness of 0.7 μm. The film was exposed through a test chart mask using a reduction projection exposure apparatus NSR-2005EX8A (manufactured by Nikon Corporation), heated at 120 ° C. for 90 seconds, and then treated with a 2.38 wt% tetramethylammonium hydroxide aqueous solution. When the resist pattern was formed by paddle development for 2 seconds, washing with water for 30 seconds and drying, a line and space pattern of 0.21 μm was formed, and the cross section of the resist pattern was slightly trapezoidal. It was a good one close to a rectangle. Further, the minimum exposure amount (hereinafter referred to as the minimum exposure amount) at which the resist pattern having a large area that can be visually confirmed was patterned and the substrate surface appeared was measured and found to be 7 mJ / cm ² . Furthermore, as a result of examining the heat resistance of the formed 0.5 μm line pattern (temperature at which a flow due to heat occurs, hereinafter referred to as heat resistance), it was 130 ° C.

However, the sample subjected to the exposure process and then left to stand for 15 minutes and then subjected to the heat treatment at 120 ° C. for 90 seconds had a T shape, and the 0.3 μm line and space pattern had the minimum resolution.

Comparative Example 5
1.05 g of polyhydroxystyrene in which 70% of the hydroxyl groups obtained in Production Example 4 were substituted with tert-butoxycarbonyloxy groups and 70% of the hydroxyl groups obtained in Production Example 8 were 1-methoxy-n-propyloxy groups. After dissolving 1.95 g of substituted polyhydroxystyrene in 16.8 g of propylene glycol monomethyl ether acetate, 0.21 g of bis (cyclohexylsulfonyl) diazomethane, 0.009 g of SAX (trade name, manufactured by Mitsui Toatsu Chemical Co., Ltd.), benzophenone 0.128 g was further added, and the resulting solution was filtered through a 0.2 μm membrane filter to prepare a positive resist coating solution.

When the resist characteristics similar to those of Reference Example 5 were evaluated for the coating solution, a 0.3 μm line and space pattern was the limit, and the resist pattern cross section was T-shaped and poor. The minimum exposure was 20 mJ / cm ² . Furthermore, as a result of examining the heat resistance of the formed 0.5 μm line pattern, it was 130 ° C.

Comparative Example 6
1.05 g of polyhydroxystyrene in which 8% of the hydroxyl groups obtained in Production Example 1 were substituted with tert-butoxycarbonyloxy groups and 70% of the hydroxyl groups obtained in Production Example 8 were 1-methoxy-n-propyloxy groups. After 1.95 g of substituted polyhydroxystyrene was dissolved in 16.8 g of propylene glycol monomethyl ether acetate, 0.21 g of bis (cyclohexylsulfonyl) diazomethane, 0.009 g of phthalic acid and 0.128 g of benzophenone were further added and dissolved. The obtained solution was filtered with a 0.2 μm membrane filter to prepare a positive resist coating solution.

When the resist characteristics similar to those of Reference Example 5 were evaluated for the coating solution, the line and space pattern of 0.3 μm was the limit, and the resist pattern cross-section exhibited a shape close to an inverted triangle and was poor. It was. The minimum exposure was 10 mJ / cm ² . Furthermore, as a result of examining the heat resistance of the formed 0.5 μm line pattern, it was 130 ° C.

Reference Example 10
In Reference Example 1, a resist pattern was formed in the same manner as in Reference Example 1 except that the substrate was a silicon wafer on which a silicon nitride insulating film (SiN) was formed. The cross section of the formed resist pattern was free from the influence of standing waves and was good near a rectangle, and a 0.23 μm line and space pattern was formed.

Reference Example 11
In Reference Example 1, a resist pattern was formed in the same manner as in Reference Example 1 except that the substrate was a silicon wafer on which a TiN metal film was formed. The cross section of the formed resist pattern was free from the influence of standing waves and was good near a rectangle, and a 0.23 μm line and space pattern was formed.

Reference Example 12
In Reference Example 3, a resist pattern was formed in the same manner as in Reference Example 3 except that the substrate was a silicon wafer on which a BPSG insulating film was formed. The cross section of the formed resist pattern was free from the influence of standing waves and was good near a rectangle, and a 0.23 μm line and space pattern was formed.

Comparative Example 7
In Comparative Example 1, a resist pattern was formed in the same manner as in Comparative Example 1 except that the substrate was a silicon wafer on which a TiN metal film was formed. The cross section of the formed resist pattern showed skirting at the substrate interface, and a 0.30 μm line and space pattern was formed.

Comparative Example 8
When a resist pattern was formed on a silicon wafer provided with a SiN film using the resist of Comparative Example 4 in the same manner as in Comparative Example 4, a skirted shape was obtained.

Reference Example 13
0.9 g of polyhydroxystyrene (weight average molecular weight 20,000, molecular weight distribution (Mw / Mn) 4.0) in which 39 mol% of the hydroxyl group obtained in Production Example 3 was substituted with a tert-butoxycarbonyloxy group, production Polypropylene styrene (weight average molecular weight 20,000, molecular weight distribution (Mw / Mn) 4.0) obtained by substituting 35 mol% of the hydroxyl group obtained in Example 5 with ethoxyethoxy group was added to propylene glycol monomethyl ether acetate 16 After dissolving in 0.8 g, 0.15 g of pyrogallol trimesylate and 6.3 mg of salicylic acid were further added, and the resulting solution was filtered with a membrane filter having a pore size of 0.2 μm to prepare a positive resist coating solution. did.

The prepared coating solution was applied onto a 6-inch silicon wafer using a spinner, and dried on a hot plate at 90 ° C. for 90 seconds to obtain a resist film having a thickness of 0.7 μm. The film was drawn using an electron beam irradiation apparatus HL-8000 (manufactured by Hitachi, Ltd.), heated at 110 ° C. for 90 seconds, and then paddle-developed with a 2.38 wt% tetramethylammonium hydroxide aqueous solution for 65 seconds. When the resist pattern was formed by washing with water for 30 seconds and then drying, a 0.12 μm contact hole was formed, and the resist pattern cross section was vertical and good. Moreover, as a result of measuring the exposure amount at this time, it was 25 micro C / cm < ² >.

Reference Example 14
In Reference Example 13, pyrogallol trimesylate, which is an acid generator, was replaced with bis (p-tert-butylphenyl) iodonium trifluoromethanesulfonate, and the addition amount thereof was 0.15 g. A positive resist coating solution was prepared.

Next, when a resist pattern was formed by the same treatment as in Reference Example 13, a 0.15 μm contact hole was formed, and the resist pattern cross section was vertical and good. The exposure dose at this time was 10 μC / cm ² .

Reference Example 15
In Reference Example 13, the positive type was changed in the same manner as in Reference Example 13 except that pyrogallol trimesylate, which is an acid generator, was replaced with 2,6-dinitrobenzyl p-toluenesulfonate and the amount added was 0.15 g. A resist coating solution was prepared.

Next, when a resist pattern was formed by the same treatment as in Reference Example 13, a contact hole of 0.14 μm was formed, and the resist pattern cross section was vertical and good. The exposure dose at this time was 35 μC / cm ² .

Reference Example 16
In Reference Example 13, the positive resist coating solution was changed in the same manner as in Reference Example 13 except that pyrogallol trimesylate, which is an acid generator, was replaced with triphenylsulfonium trifluoromethanesulfonate and the addition amount was 0.15 g. Prepared.

Next, when a resist pattern was formed by the same treatment as in Reference Example 13, a 0.15 μm contact hole was formed, and the resist pattern cross section was vertical and good. The exposure dose at this time was 10 μC / cm ² .

Example 1
0.9 g of polyhydroxystyrene (weight average molecular weight 20,000, molecular weight distribution (Mw / Mn) 4.0) in which 39 mol% of the hydroxyl group obtained in Production Example 3 was substituted with a tert-butoxycarbonyloxy group, Production Example Polyhydroxystyrene (weight average molecular weight 20,000, molecular weight distribution (Mw / Mn) 4.0) in which 39 mol% of the hydroxyl group obtained in 7 was substituted with 1-methoxy-n-propyloxy group was 2.1 g. After dissolving in 16.8 g of propylene glycol monomethyl ether acetate, 0.03 g of bis (cyclohexylsulfonyl) diazomethane, 0.15 g of bis (2,4-dimethylphenylsulfonyl) diazomethane, and 0.0064 g of o-hydroxybenzoic acid were further added. The solution obtained by dissolution is filtered through a membrane filter having a pore size of 0.2 μm, It was prepared as a coating liquid type resist.

When the resist characteristics similar to those of Reference Example 5 were evaluated for the prepared coating solution, a 0.2 μm line and space pattern was formed, and the resist pattern cross section was slightly waved in actual use. It was a thing with no trouble, and was a good rectangle. The minimum exposure was 5 mJ / cm ² . Furthermore, as a result of examining the heat resistance of the formed 0.5 μm line pattern, it was 130 ° C. When the depth of focus was evaluated in the same manner as in Reference Example 1, it was A. Furthermore, as a result of examining the storage stability of the resist solution, no foreign matter was generated for 6 months.

  As described above, the resist acid generator according to the present invention can achieve high sensitivity, high resolution, and high heat resistance when used in a resist composition, and also improves the depth of focus characteristics. be able to. The positive resist composition using the acid generator for a resist according to the present invention has high sensitivity and high resolution, heat resistance, depth of focus characteristics, stability over time, and storage stability of a resist solution. In addition to being superior, it is useful for the production of resist patterns with no substrate dependence and excellent profile shape. Especially for the production of patterns using chemically amplified positive resist compositions sensitive to excimer lasers such as KrF and ArF. Are suitable.

Claims (14)

  A resist acid generator comprising a mixture of bis (cyclohexylsulfonyl) diazomethane and bis (2,4-dimethylphenylsulfonyl) diazomethane.   (A) It is used as the component (B) in a positive resist composition comprising a resin component whose solubility in an alkaline aqueous solution is increased by the action of an acid and (B) a compound that generates an acid upon irradiation with radiation. The acid generator for resists according to claim 1. The component (A) is such that (a) 10 to 60 mol% of the hydroxyl group is represented by the following general formula (1)

(Wherein R ¹ is a hydrogen atom or a methyl group, R ² is a methyl group or an ethyl group, and R ³ is a lower alkyl group having 1 to 4 carbon atoms). The acid generator for resists according to claim 2, which is polyhydroxystyrene having a weight average molecular weight of 8,000 to 22,000.   The component (A) is polyhydroxystyrene having a weight average molecular weight of 8,000 to 22,000 in which 10 to 60 mol% of the hydroxyl group (b) is substituted with a tert-butoxycarbonyloxy group. Item 3. The acid generator for a resist according to Item 2. The component (A) is such that (a) 10 to 60 mol% of the hydroxyl group is represented by the following general formula (1)

(Wherein R ¹ is a hydrogen atom or a methyl group, R ² is a methyl group or an ethyl group, and R ³ is a lower alkyl group having 1 to 4 carbon atoms). Polyhydroxystyrene having a weight average molecular weight of 8,000 to 22,000, and (b) polyhydroxystyrene having a weight average molecular weight of 8,000 to 22,000 in which 10 to 60 mol% of the hydroxyl group is substituted with a tert-butoxycarbonyloxy group. The acid generator for resist according to claim 2, which is a mixture with styrene.   Furthermore, it is used as said (B) component in the positive resist composition containing (C) organic carboxylic acid compound, The acid generator for resists as described in any one of Claims 2-5 characterized by the above-mentioned.   The resist acid according to claim 6, wherein the component (C) is at least one selected from the group consisting of aromatic carboxylic acids, alicyclic carboxylic acids, and unsaturated aliphatic carboxylic acids. Generating agent. The aromatic carboxylic acid compound is represented by the following general formula (2)

(Wherein R ⁴ and R ⁵ each independently represent a hydrogen atom, a hydroxyl group, a nitro group, a carboxyl group, or a vinyl group, provided that R ⁴ and R ⁵ are both hydrogen atoms). The resist acid generator according to claim 7, wherein the acid generator is used as a resist. The aromatic carboxylic acid compound is represented by the following general formula (3)

8. The resist acid generator according to claim 7, wherein n is a compound represented by the formula (wherein n represents 0 or an integer of 1 to 10).   The alicyclic carboxylic acid is composed of 1,1-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, and 1,1-cyclohexyldiacetic acid The acid generator for resists according to claim 7, which is at least one selected from the group consisting of:   The unsaturated aliphatic carboxylic acid compound is acrylic acid, crotonic acid, isocrotonic acid, 3-butenoic acid, methacrylic acid, 4-pentenoic acid, propiolic acid, 2-butynoic acid, maleic acid, fumaric acid, and acetylene carboxylic acid. The acid generator for a resist according to claim 7, wherein the acid generator is at least one selected from the group consisting of:   The acid generator for a resist according to claim 6, wherein the component (C) contains 0.01 to 1% by weight based on the total amount of the component (A) and the component (B). Furthermore, it is used as said (B) component in the positive resist composition containing a light absorber, The acid generator for resists as described in any one of Claims 2-12 characterized by the above-mentioned. 14. The resist acid generator according to claim 13, wherein the light absorber is benzophenone.