JP2000038486A - Mixed resin composition and positive type resist composition using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a mixed resin composition that has high sensitivity and high resolution and can form good resist patterns by using a specific compound as a resin component for increasing the solubility in an aqueous alkali by the action of acid. SOLUTION: This mixed resin composition includes (A) 10-70 wt.% of polyhydroxystyrene in which 10-60 mol.% of the hydroxy groups are converted to tertiary butyloxy group and (B) 30-90 wt.% of polyhydroxy-styrene in which 10-60 mol.% of hydroxy groups are converted to the residual groups of the formula (R1 is H, methyl; R2 is methyl, ethyl; R3 is a lower alkyl). In a preferred embodiment, this composition contains additionally (C) a compound that liberates acid by irradiation with radioactive rays. Further, the component A and the component B preferably have a molecular weight distribution (Mw/Mn) of 3-5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a mixed resin composition containing a mixture of polyhydroxystyrenes each substituted by two different substituents, as a resin component whose solubility in an aqueous alkali solution is increased by the action of an acid. And a positive resist composition using the same, and more specifically, a chemically amplified positive resist composition sensitive to radiation such as excimer lasers such as ultraviolet rays, far ultraviolet rays, KrF, and ArF, X-rays, and electron beams. And a positive resist composition containing the mixed resin composition.

[0002]

2. Description of the Related Art Conventionally, semiconductor devices such as ICs and LSIs have been manufactured by repeating steps such as photolithography, etching, impurity diffusion and wiring formation using a photoresist composition several times. In photolithography, a photoresist composition is applied to a silicon wafer by a method such as spin coating 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. Then, etching is performed using the resist pattern as a protective film. Hitherto, the photoresist composition used in the photolithography has a resolution required for submicron (1 μm or less), half micron (0.5 μm or less), and g-line (436 nm). ,
Positive photoresists containing alkali-soluble novolak resins utilizing ultraviolet rays such as i-rays (365 nm) and quinonediazide group-containing compounds as basic components have been put to practical use.

However, in recent years, the miniaturization of semiconductor elements has been increasing, and today, quarter-micron (0.25
Mass production of ultra-LSIs using ultra-fine patterns (μm or less) is about to begin. In order to obtain such an ultra-fine pattern of quarter micron, it is difficult to obtain a conventional positive photoresist containing alkali-soluble novolak resin and a quinonediazide group-containing compound as basic components. Therefore, far ultraviolet rays (200 to 300 nm) having a shorter wavelength are difficult. , KrF, Ar
There is a demand for the development of a resist using an excimer laser such as F, an electron beam and an X-ray. In addition to achieving high resolution as such a resist, a chemically amplified resist capable of achieving a high sensitivity with a quantum yield of 1 or more utilizing a catalytic reaction and a chain reaction of an acid generated by irradiation of radiation and achieving high sensitivity is provided. It is receiving attention and is being actively developed.

As the chemically amplified resist, for example, a resist composition comprising 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 is disclosed in US Pat. No. 628. However, the resist composition is not sufficient in resolution and depth of focus characteristics, and when left for a certain period of time after exposure due to deactivation of acid generated by exposure peculiar to the chemically amplified resist, and then developed. (Hereinafter referred to as stability over time), that is, bridging in which the upper portion of the resist pattern is connected in an eaves-like manner. If such bridging is performed, a desired wiring pattern cannot be obtained, which is fatal in semiconductor device manufacturing. As a method of solving such a problem of the withdrawal time, there is a method of providing a top coat layer on the resist layer to prevent deactivation of the acid generated by exposure, but such a method requires an additional manufacturing process. It is not preferable because the throughput is lowered and the cost is increased.
Therefore, there is a strong demand for a resist which does not require a topcoat layer and has excellent stability over time.

[0005]

The inventors of the present invention have conducted intensive studies, and as a result, as a resin component whose solubility in an aqueous alkali solution is increased by the action of an acid, each of the resin components is substituted with two different substituents. By using a mixed resin composition containing a mixture of polyhydroxystyrene as a resin component of a positive resist composition, it has high sensitivity, high resolution, excellent heat resistance, and stability over time. It has been found that a positive resist composition which is excellent in resist properties and can form a good resist pattern can be obtained, and the present invention has been completed. Ie

The present invention provides a mixed resin composition containing a mixture of polyhydroxystyrenes each substituted with two different substituents, as a resin component whose solubility in an aqueous alkali solution is increased by the action of an acid. With the goal.

The present invention also includes a compound (hereinafter referred to as an acid generator) which generates an acid upon irradiation with radiation in addition to the above mixture of polyhydroxystyrene, and which contains radiation, especially deep UV, KrF, ArF or the like. Positive type that has excellent light transmittance to excimer laser light, high sensitivity, high resolution, excellent heat resistance, excellent stability over time, and good resist pattern with good profile shape. It is intended to provide a resist composition.

[0008]

To achieve the above object, the present invention provides (a) polyhydroxystyrene in which 10 to 60 mol% of hydroxyl groups are tert-butyloxy groups;
10 to 60 mol% of the hydroxyl group is represented by the general formula 4

[0009]

Embedded image 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. And a positive resist composition using the mixed resin composition.

The mixing ratio of the above polyhydroxystyrene is 10 to 70% by weight for the component (a) and 30 to 9 for the component (b).
0% by weight, preferably 20 to 50% by weight of the component (A),
The component (b) preferably has a content of 50 to 80% by weight. And
Specific examples of the residue represented by the general formula 4 of the component (b) include, for example, 1-methoxyethoxy group, 1-ethoxyethoxy group, 1-n-propoxyethoxy group, 1-isopropoxyethoxy group, -N-butoxyethoxy group, 1-isobutoxyethoxy group, 1- (1,1-dimethylethoxy) -1-methylethoxy group, 1-methoxy-1-methylethoxy group, 1-ethoxy-1-methylethoxy group , 1-n-propoxy-1-methylethoxy group, 1-isobutoxy-1-methylethoxy group, 1-methoxy-n-propoxy group, 1-ethoxy-n-propoxy group and the like. Among them, 1-ethoxyethoxy group and 1-methoxy-n-propoxy group are particularly sensitive,
This is preferable because the resolving power is improved in a well-balanced manner.

A positive resist composition can be obtained by further adding an acid generator to the mixed resin composition. In the positive resist composition, the acid generated from the acid generator is (a). Decomposes the tert-butyloxy group of the component and the residue represented by the general formula (4) of the component (b), and appropriately balances the solubility of the resin component with alkali and the dissolution inhibiting ability, resulting in high sensitivity and high resolution. And high heat resistance can be achieved.

The above-mentioned component (a) is used to convert the tert-butyl group of polytert-butyloxystyrene with hydrochloric acid, sulfuric acid,
It can be obtained by partial elimination with an acid such as oxalic acid or p-toluenesulfonic acid, and the remaining t
The tert-butyloxy group accounts for 10 to 60 mol%, preferably 20 to 50 mol% of the hydroxyl group of polyhydroxystyrene.
It is necessary to be within the range. If the tert-butyl group is less than 10 mol%, a resist pattern having an excellent profile cannot be obtained. If the tert-butyl group exceeds 60 mol%, sensitivity is lowered, which is not preferable.
Is valid.

On the other hand, the component (b) converts the hydroxyl group of polyhydroxystyrene with, for example, 1-chloro-1-ethoxyethane or 1-chloro-1-methoxypropane according to a known substitution reaction according to the general formula (4). With a substitution rate of 10 to 60 mol%, preferably 20 to 60 mol%.
It must be 50 mol%. This replacement rate is 10
If the amount is less than mol%, a pattern having an excellent shape cannot be obtained. If the amount exceeds 60 mol%, the sensitivity of the resist is lowered, which is not preferable. In practice, the range of 20 to 50 mol% is effective.

Further, the weight average molecular weight of each of the above resin components is in the range of 3,000 to 30,000, preferably 8,000 to 22,000 based on polystyrene based on gel permeation chromatography (GPC). . When the weight-average molecular weight is less than the above range, the coating properties are poor, and when the weight-average molecular weight exceeds the above upper limit, the solubility in an alkaline aqueous solution is reduced. Furthermore, each resin molecular weight distribution expressed by the ratio of the weight average molecular weight to number average molecular weight (M _W / M _n) is 3-5
Is preferably within the range.

As the above-mentioned acid generator, those which have hitherto been known as acid generators can be used without any particular limitation. Specifically, (a) bis (p-toluenesulfonyl) diazomethane, methylsulfonyl -P-toluenesulfonyldiazomethane, 1-cyclohexylsulfonyl-1- (1,1-dimethylethylsulfonyl) diazomethane, bis (1,1-dimethylethylsulfonyl) diazomethane, bis (1-methylethylsulfonyl) diazomethane, bis (cyclohexyl) Sulfonyl) diazomethane, bis (2,4-dimethylphenylsulfonyl) diazomethane, bis (4-ethylphenylsulfonyl) diazomethane, bis (3-methylphenylsulfonyl) diazomethane, bis (4-methoxyphenylsulfonyl) diazomethane, bis ( - fluorophenylsulfonyl)
Diazomethane, bis (4-chlorophenylsulfonyl)
Bissulfonyldiazomethanes such as diazomethane and bis (4-tert-butylphenylsulfonyl) diazomethane; (b) 2-methyl-2- (p-toluenesulfonyl) propiophenone; 2- (cyclohexylcarbonyl) -2- (p -Toluenesulfonyl) propane, 2
-Methanesulfonyl-2-methyl- (4-methylthio)
Sulfonylcarbonylalkanes such as propiophenone, 2,4-dimethyl-2- (p-toluenesulfonyl) pentan-3-one, (c) 1-p-toluenesulfonyl-1-cyclohexylcarbonyldiazomethane, 1
-Diazo-1-methylsulfonyl-4-phenyl-2-
Butanone, 1-cyclohexylsulfonyl-1-cyclohexylcarbonyldiazomethane, 1-diazo-1-cyclohexylsulfonyl-3,3-dimethyl-2-butanone, 1-diazo-1- (1,1-dimethylethylsulfonyl) -3, 3-dimethyl-2-butanone, 1-acetyl-1- (1-methylethylsulfonyl) diazomethane, 1-diazo-1- (p-toluenesulfonyl)-
3,3-dimethyl-2-butanone, 1-diazo-1-benzenesulfonyl-3,3-dimethyl-2-butanone,
1-diazo-1- (p-toluenesulfonyl) -3-methyl-2-butanone, cyclohexyl 2-diazo-2- (p-toluenesulfonyl) acetate, tert-butyl 2-diazo-2-benzenesulfonylacetate, 2 -Diazo-
2-isopropyl 2-methanesulfonyl acetate, 2-diazo-
Sulfonylcarbonyldiazomethanes such as cyclohexyl 2-benzenesulfonylacetate and tert-butyl 2-diazo-2- (p-toluenesulfonyl) acetate;
(D) 2-nitrobenzyl p-toluenesulfonate, p
-2,6-dinitrobenzyl toluenesulfonate, p-
Nitrobenzyl derivatives such as 2,4-dinitrobenzyl trifluoromethylbenzenesulfonate, (e) methanesulfonic acid ester of pyrogallol, benzenesulfonic acid ester of pyrogallol, p-toluenesulfonic acid ester of pyrogallol, p-methoxybenzene of pyrogallol Sulfonates, mesitylenesulfonate of pyrogallol, benzylsulfonate of pyrogallol, methanesulfonate of alkyl gallate, benzenesulfonate of alkyl gallate, p-toluenesulfonate of alkyl gallate, alkyl gallate Such as p-methoxybenzenesulfonate, mesitylenesulfonate of alkyl gallate and benzylsulfonate of alkyl gallate Carboxymethyl compound with an aliphatic or aromatic sulfonic acid esters, and the like. The alkyl group in the alkyl gallate has 1 to 1 carbon atoms.
5 alkyl groups, especially octyl and lauryl groups, are preferred. Further, (f) an onium salt-based acid generator represented by the following general formulas (5) and (6), and (g) a benzointresheet-based acid generator represented by the following general formula (7) can also be used.

[0016]

Embedded image (R ⁴ and R ⁵ are an aryl group and an aryl group having a substituent, and may be the same or different;
^- the _{^{AsF - 6, PF - 6,}} BF - 4 SbF - 6, CF 3 SO - 3 of either)

[0017]

Embedded image (R ^6, R ⁷ and R ^8, an aryl group, an aryl group having a substituent, each may be the same or different, X ^- is _{^{AsF - 6, PF - 6,}} BF - 4 SbF - ₆ , CF ₃ S
O ^- ₃ )

[0018]

Embedded image (R ⁹ and R ¹⁰ are an aryl group or an aryl group having a substituent and may be the same or different, and R ¹¹ and R ¹² are a hydrogen atom, a lower alkyl group, a hydroxyl group or an aryl group and may be the same or different. (N is 0 or 1)

Specific examples of the onium salts represented by the above general formulas 6 and 7 include the following compounds of the following chemical formulas 8 to 29.

[0020]

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[0021]

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[0022]

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[0023]

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[0024]

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[0025]

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[0026]

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[0027]

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[0028]

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[0029]

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[0030]

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[0031]

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[0032]

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[0033]

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[0034]

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[0035]

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[0036]

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[0037]

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[0038]

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[0039]

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[0040]

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[0041]

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Of the above onium salts, onium salts having trifluoromethanesulfonate as an anion are preferable because they do not contain atoms used as diffusing agents such as phosphorus, boron and antimony used in the production of semiconductor devices.

(G) Specific examples of the benzoin tosylate-based acid generator include the following compounds of formulas 30 to 34.

[0044]

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[0045]

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[0046]

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[0047]

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[0048]

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The above-mentioned acid generators may be used alone,
A combination of more than one species may be used. Among the acid generators, bissulfonyldiazomethanes are particularly preferable as resists for excimer lasers. Among them, bis (cyclohexylsulfonyl) diazomethane or bis (2,4-dimethylphenylsulfonyl) diazomethane, or Are preferred. In particular, the mixture is preferable because the mixture has higher sensitivity.

As the acid generator for the electron beam resist, acid generators other than the above (a) and (c), in particular,
(D) nitrobenzyl derivatives, in particular 2,6-dinitrobenzyl p-toluenesulfonate, (e) aliphatic or aromatic sulfonic acid esters of polyhydroxy compounds,
Of these, pyrogallol trimesylate, an onium salt of (f), bis (p-tert-butylphenyl) iodonium trifluoromethanesulfonate, triphenylsulfonium trifluoromethanesulfonate, and (g) a benzoin tosylate acid generator are preferred. The mixing ratio of the acid generator is 1 to 20 parts by weight, preferably 2 to 10 parts by weight, based on 100 parts by weight of the resin component. If the amount of the acid generator is less than 1 part by weight, the effect is insufficient. If the amount exceeds 20 parts by weight, the acid generator cannot be completely dissolved in the solvent and the miscibility with the resin component is poor.

When the mixed resin composition of the present invention is used as a positive resist composition, a light absorbing agent is added to improve the sensitivity and resolution in addition to the above resin component and acid generator. Is good. Examples of the light absorbing agent include mercaptooxazole, mercaptobenzoxazole, mercaptooxazoline, mercaptobenzothiazole, benzoxazolinone, benzothiazolone, mercaptobenzimidazole, urazole, thiouracil, mercaptopyrimidine, benzophenone and derivatives thereof. In particular, benzophenone is preferably used because it has an effect of improving the sensitivity and the resolution, and also has an effect of suppressing the influence of standing waves and forming a rectangular resist pattern without forming a wavy cross-sectional shape. The compounding amount of the light absorbing agent is not more than 30% by weight, preferably 0.5 to 15% by weight, based on the total amount of the components (a), (b) and the acid generator. It is blended in the range. If the amount is more than 30% by weight, the profile shape is unfavorably deteriorated.

The mixed resin composition of the present invention is preferably used in the form of a solution obtained by dissolving each component in a solvent, particularly when using a positive resist composition. Examples of such solvents include ketones such as acetone, methyl ethyl ketone, cyclohexanone, and methyl isoamyl ketone; ethylene glycol, ethylene glycol monoacetate, diethylene glycol, diethylene glycol monoacetate, propylene glycol, propylene glycol monoacetate, dipropylene glycol or dipropylene glycol. Polyhydric alcohols such as monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether or monophenyl ether of propylene glycol monoacetate and derivatives thereof; cyclic ethers such as dioxane; and methyl lactate, ethyl lactate and methyl acetate , Ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethoxypropyl It can be mentioned esters such as phosphate ethyl. These may be used alone or as a mixture of two or more.

The positive resist composition comprising the mixed resin composition of the present invention may further comprise, if desired, a miscible additive in addition to the component (A), the component (B) and the acid generator, for example, the performance of the resist film. It is possible to add and contain commonly used materials such as an additional resin, a plasticizer, a stabilizer, a colorant, a surfactant and the like for improving the quality.

In using the above positive resist composition, the positive resist composition is dissolved in a solvent, applied to a substrate or the like using a spinner or the like, dried, and a photosensitive layer is formed. Deep with projection exposure equipment etc.
-Irradiation with UV light, excimer laser light such as KrF, ArF or the like through a desired mask pattern or drawing with an electron beam, and a weak alkaline solution such as a developing solution, for example, an aqueous solution of 1 to 10% by weight of tetramethylammonium hydroxide. It is preferable to perform development processing using an aqueous solution or the like. As described above, a good resist pattern faithful to the mask pattern can be formed.

[0055]

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

Production Example 1 (Synthesis of polyhydroxystyrene having 35 mol% of hydroxyl group as tert-butyloxy group) Weight average molecular weight 10,
000, 120 g of polytert-butyloxystyrene having a molecular weight distribution ( _Mw / _Mn ) of 4 was dissolved in 480 g of dioxane, and 21.6 g of an aqueous hydrochloric acid solution was added to this solution.
Stir at 2 ° C. for 2 hours. Next, a 20-fold amount of pure water was added to the obtained solution, and the mixture was stirred to precipitate polyhydroxystyrene from which tert-butyloxy groups had been eliminated by 65 mol%. The precipitate is washed with pure water, dehydrated and dried,
125 g of polyhydroxystyrene in which 35 mol% of hydroxyl groups were tert-butyloxy groups were obtained.

Production Example 2 (Synthesis of polyhydroxystyrene in which 35 mol% of hydroxyl groups were substituted with ethoxyethoxy groups) Weight average molecular weight 10,
000, 120 g of polyhydroxystyrene having a molecular weight distribution (M _w / M _n ) 4 of N, N-dimethylacetamide 680
g, and 37.2 g of 1-chloro-1-ethoxyethane was added to the solution, and the mixture was completely dissolved by stirring. Then, 78.8 g of triethylamine was added to the solution while stirring.
It was added dropwise over 0 minutes. After completion of the dropwise addition, the mixture was stirred for about 3 hours. Next, a 20-fold amount of pure water was added to the obtained solution, and the mixture was stirred to obtain 130 g of polyhydroxystyrene in which a hydroxyl group was substituted with a 1-ethoxyethoxy group.

Example 1 Polyhydroxystyrene in which 35 mol% of the hydroxyl groups obtained in Production Example 1 was a tert-butyloxy group {weight average molecular weight 10,000, molecular weight distribution (M _w / M _n ) 4}
48 g, polyhydroxystyrene in which 35 mol% of the hydroxyl group obtained in Production Example 2 was protected with an ethoxyethoxy group 基 weight average molecular weight 10,000, molecular weight distribution (M _w / M _n )
4｝ 1.48 g was dissolved in 16.8 g of propylene glycol monomethyl ether acetate, and 0.148 g of bis (cyclohexylsulfonyl) diazomethane and 0.093 g of benzophenone were further added and dissolved to obtain a solution having a pore diameter of 0.2 μm. The solution was filtered through a membrane filter to prepare a positive resist coating solution.

The prepared coating solution was coated with a spinner 6
It was applied on an inch silicon wafer and dried on a hot plate at 90 ° C. for 90 seconds to obtain a resist film having a thickness of 0.7 μm. This film has a reduced projection exposure apparatus NSR-2005E
After excimer laser exposure through a test chart mask using X8A (manufactured by Nikon Corporation),
Heated for 0 seconds, and then paddle-developed with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 65 seconds,
After washing with water and drying for 30 seconds, a resist pattern was formed.
The obtained resist pattern was a 0.21 μm line and space pattern. Also, the formed 0.5
It was 130 ° C. as a result of examining the heat resistance (temperature at which a flow due to heat occurs) of the μm line pattern.

After the above exposure treatment, the resist pattern was left standing for 15 minutes and then heated at 120 ° C. for 90 seconds to form a resist pattern.
m line and space patterns were formed.

COMPARATIVE EXAMPLE 1 1.05 g of polyhydroxystyrene in which 8% of hydroxyl groups were tert-butyloxy groups and 1.95 g of polyhydroxystyrene in which 8% of hydroxyl groups were substituted with methoxy-n-propyloxy groups were treated with propylene glycol monomethyl After dissolving in 16.8 g of ether acetate, 0.21 g of bis (cyclohexylsulfonyl) diazomethane, o
-Nitrobenzoic acid 0.009 g, benzophenone 0.1
28 g was further added, and the solution obtained by dissolution was 0.2 μm.
The mixture was filtered through a membrane filter to prepare a coating solution for a positive resist.

The resist properties of the coating solution were evaluated in the same manner as in Example 1 except that the temperature of the post-exposure bake was changed from 120 ° C. to 110 ° C. Met.

COMPARATIVE EXAMPLE 2 1.05 g of polyhydroxystyrene in which 70% of hydroxyl groups were tert-butyloxy groups and 70% of hydroxyl groups were 1-
After dissolving 1.95 g of polyhydroxystyrene substituted with a methoxy-n-propyloxy group in 16.8 g of propylene glycol monomethyl ether acetate,
Bis (cyclohexylsulfonyl) diazomethane 0.2
1 g, SAX (trade name, manufactured by Mitsui Toatsu Chemicals) 0.009
g and benzophenone (0.128 g) were 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 properties of the coating solution were evaluated in the same manner as in Comparative Example 1, the limit was a line-and-space pattern of 0.3 μm, and the cross section of the resist pattern was T-shaped and poor. Was. Also,
The minimum exposure amount (hereinafter referred to as minimum exposure amount) in which a large area resist pattern that can be visually confirmed was patterned and the substrate surface appeared was 20 mJ / cm ² . As a result of examining the heat resistance of the formed 0.5 μm line pattern,
130 ° C.

Comparative Example 3 1.05 g of polyhydroxystyrene in which 8% of hydroxyl groups were tert-butyloxy groups and 1.95 g of polyhydroxystyrene in which 70% of hydroxyl groups were substituted with 1-methoxy-n-propyloxy group were propylene After dissolving in 16.8 g of glycol monomethyl ether acetate, bis (cyclohexylsulfonyl) diazomethane 0.21 was dissolved.
g, phthalic acid 0.009 g, benzophenone 0.128
g was further added, and the resulting solution was filtered through a 0.2 μm membrane filter to prepare a coating solution for a positive resist.

When the resist properties of the above coating liquid were evaluated in the same manner as in Comparative Example 1, the limit was a line and space pattern of 0.3 μm, and the cross section of the resist pattern had a shape close to an inverted triangle and was poor. Was something. The minimum exposure was 10 mJ / cm ² . Further, as a result of examining the heat resistance of the formed 0.5 μm line pattern, it was 130 ° C.

[0067]

The mixed resin composition of the present invention contains a mixture of polyhydroxystyrenes each substituted with two different substituents as a resin component whose solubility in an aqueous alkali solution is increased by the action of an acid. The positive resist composition prepared using the mixed resin composition is a chemically amplified type, and has high sensitivity, high resolution, high heat resistance, excellent stability over time, and a profile shape. And is sensitive to radiation, especially ultraviolet, far ultraviolet, excimer lasers such as KrF, ArF, X-rays and electron beams, and is particularly effective for microfabrication in ultra LSI manufacturing processes. is there.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 21/027 H01L 21/30 502R (72) Inventor Akiyoshi Yamazaki 150 Nakamaruko Nakahara-ku, Kawasaki-shi, Kanagawa Tokyo (72) Inventor Yoshihiro Sakai 150 Nakamurako, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Tokyo Chemical Industry Co., Ltd. (72) Toshimasa Nakayama 150 Nakamaruko, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Tokyo Ohka Kogyo Co., Ltd. Inside the corporation

Claims (11)

[Claims] (1) 10 to 60 mol% of a hydroxyl group is
polyhydroxystyrene having a t-butyloxy group;
(B) 10 to 60 mol% of the hydroxyl groups is represented by the 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. A mixed resin composition. (A) 10 to 60 mol% of hydroxyl groups is
polyhydroxystyrene having a t-butyloxy group;
(B) 10 to 60 mol% of the hydroxyl groups is represented by the general formula 2 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. A mixed resin composition further comprising a compound capable of generating an acid upon irradiation with radiation. (3) The component (A) has 10 to 60 mol% of hydroxyl groups as tert-butyloxy groups, and has a weight average molecular weight of 3,
000 to 30,000, molecular weight distribution (M _w / M _n ) of 3 to
5 polyhydroxystyrene, wherein component (b) is a hydroxyl group 1
0 to 60 mol% is represented by the general formula 3 (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), and the weight average molecular weight is 3 The mixed resin composition according to claim 1, wherein the mixed resin composition is a polyhydroxystyrene having a molecular weight distribution (M _w / M _n ) of 3 to 5, 000 to 30,000. 4. The mixed resin composition according to claim 1, wherein the weight average molecular weight of the components (a) and (b) is in the range of 8,000 to 22,000. 5. The composition according to claim 1, wherein component (a) in the mixed resin composition is 10 to 7%.
The mixed resin composition according to claim 1 or 2, wherein 0% by weight and (b) component are in a range of 30 to 90% by weight. 6. The composition according to claim 1, wherein component (a) in the mixed resin composition is 20 to 5%.
The mixed resin composition according to claim 5, wherein 0% by weight and the component (b) are in the range of 50 to 80% by weight. 7. The mixed resin composition according to claim 2, wherein the compound generating an acid upon irradiation with radiation is bissulfonyldiazomethane. 8. The compound according to claim 2, wherein the compound capable of generating an acid upon irradiation with radiation is contained in an amount of 1 to 20 parts by weight based on 100 parts by weight of the total of the components (a) and (b). A mixed resin composition. 9. A positive resist composition comprising the mixed resin composition according to claim 2. 10. The positive resist composition according to claim 9, further comprising a light absorbing agent. 11. The positive resist composition according to claim 10, wherein the light absorbing agent is benzophenone.