JP2000029209A - Positive type resist composition and its preparation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a positive type resist compsn. having highly balanced sensitivity, resolution, pattern shape and heat resistance by incorporating specified compds. and specifying the proportion of the area of peaks on the higher molecular side of the principal peak present in a region in which holding time is specified time and above to the area of all peaks obtd. at a specified detection wavelength. SOLUTION: The resist compsn. contains an alkali-soluble phenolic resin, a quinonediazidosulfonic ester of a polyhydroxy compd. having a four-arom. ring skeleton represented by formula I and a quinonediazidosulfonic ester of a polyhydroxy compd. having a two-arom. ring skeleton represented by formula II. The proportion of the area of peaks on the higher molecular side of the principal peak present in a region in which holding time is >=20 min. to the area of all peaks obtd. at 470 nm detection wavelength is 40-90%. In the formulae, (k) and (m) are each 1 or 2, R1-R5 and R10-R14 are each halogen, hydroxyl or the like, R6-R9 and R25-R34 are each H, halogen or the like and X and Y are each a single bond, -O- or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positive resist composition containing an alkali-soluble phenol resin and two kinds of quinonediazidesulfonic acid esters, and more particularly, to a composition having a high sensitivity, resolution, pattern shape, and heat resistance. The present invention relates to a positive resist composition which is excellent in storage stability and remarkably excellent in storage stability, and a method for producing the same. The positive resist composition of the present invention is particularly useful as a photoresist material for fine processing in the production of semiconductor devices, magnetic bubble memory devices, integrated circuits, and the like.

[0002]

2. Description of the Related Art In order to perform fine processing by photolithography, a solution containing a resist material is applied to a substrate on which a layer to be processed such as a metal film is formed, and dried to form a resist film (photosensitive film). ) Is formed, a latent image is formed by irradiating actinic rays in a pattern, and then developed to form a negative or positive fine resist pattern. Using the resist pattern remaining on the substrate as a protective film,
After performing processing such as etching, ion implantation, and doping on the layer to be processed, the resist pattern is removed.
In a positive resist material, the non-irradiated portion of the resist film is more soluble in the developer than in the non-irradiated portion to give a positive image, and in a negative resist material, the solubility of the non-irradiated portion of the resist film is higher. To give a negative image.

Conventionally, as a resist material for forming a semiconductor element, for example, a negative resist composition comprising a cyclized polyisoprene and a bisdiazide compound has been known. However, since this negative resist composition needs to be developed with an organic solvent, it has a large swelling and its resolution is limited, so that it cannot cope with the production of a highly integrated semiconductor. A negative resist composition containing polyglycidyl methacrylate has high sensitivity but is inferior in resolution and dry etching resistance.

On the other hand, for this negative resist material,
Positive resist materials are considered to be sufficiently compatible with high integration of semiconductors because of their excellent resolution. At present, a positive resist material generally used in this field is a positive resist composition containing an alkali-soluble phenol resin such as a novolak resin and a quinonediazide compound (photosensitizer). This positive resist composition can be developed with an alkaline aqueous solution and has excellent resolution. Further, the positive resist composition,
Improvements in the performance itself and in the performance of the exposure apparatus have led to improvements in resolution and the formation of fine patterns of 1 μm or less. However, conventional positive resist compositions have not always achieved satisfactory results in terms of various characteristics such as sensitivity, resolution, pattern shape, and heat resistance, and further improvement in performance is desired.

In recent years, it has been proposed to use quinonediazide sulfonic acid esters of various polyhydroxy compounds as a photosensitizer in a positive resist composition containing an alkali-soluble phenol resin and a photosensitizer (JP-A-2-296248). No., JP-A-2-296249
issue). However, the positive resist compositions specifically disclosed in these documents do not have sufficient resist properties such as sensitivity, resolution, heat resistance, and pattern shape, and are required to be further improved.

Recently, an alkali-soluble phenolic resin,
A positive resist composition containing a quinonediazidesulfonic acid ester of a polyhydroxy compound having a polyaromatic ring skeleton in which four or more benzene rings are connected in series has been proposed (US Pat. No. 5,407,779; U.S. Patent No. 5,629,128, U.S. Patent No. 5,609,98
No. 2, U.S. Pat. No. 5,47,814, WO 96/20
430). Although the performance of these positive resist compositions differs depending on the specific composition, they are improved in resolution, pattern shape, remaining film ratio, exposure margin, and the like, as compared with conventional resist compositions. However, in view of the recent high demands on resist characteristics, it is still not enough, and it is desired to develop a positive resist composition in which various resist characteristics such as sensitivity, resolution, pattern shape, and heat resistance are highly balanced. ing. Further, the known resist compositions have insufficient storage stability over a long period of time, and a positive resist composition having excellent storage stability is desired.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a positive resist composition which is excellent in sensitivity, resolution, pattern shape, heat resistance and storage stability, and a method for producing the same. is there. The present inventors have conducted intensive studies to overcome the problems of the prior art, and as a result, in a positive resist composition containing an alkali-soluble phenol resin and quinonediazide sulfonic acid ester,
As a quinonediazidesulfonic acid ester of a photosensitizer,
(1) a quinonediazidosulfonic acid ester of a specific 4-aromatic ring skeleton polyhydroxy compound having four benzene rings, and (2) a quinonediazide sulfone of a specific 2-aromatic ring skeleton polyhydroxy compound having two benzene rings It has been found that a combined use of an acid ester enables the production of a positive resist composition having various properties highly balanced.

According to the study results of the present inventors, the positive resist composition containing the quinonediazide sulfonic acid ester of the polyhydroxy compound having a 4-aromatic ring skeleton has a sensitivity, a resolution, a remaining film ratio, an exposure margin, and a pattern shape. However, heat resistance is not sufficient, and further improvement in sensitivity is desirable. On the other hand, the positive resist composition containing the quinonediazidosulfonic acid ester of a polyhydroxy compound having a two-aromatic ring skeleton has insufficient resolution and pattern shape. However, it has been found that by using these in combination, a positive resist composition exhibiting excellent resist characteristics in all of sensitivity, resolution, pattern shape, and heat resistance can be obtained. The positive resist composition of the present invention is suitable for fine processing of 1 μm or less, preferably 0.5 μm or less, and in addition to the above-mentioned various properties, is excellent in the residual film ratio and the exposure margin.

The present inventors have further studied and found that
The peak obtained at a detection wavelength of 470 nm by gel permeation chromatography (GPC) using tetrahydrofuran by a method such as heat treatment of the positive resist composition exists in a region where the retention time is 20 minutes or more. By adjusting the polymer side from the main peak to fall within the range of 40 to 90% with respect to the total peak area, a positive resist composition excellent in the above-mentioned various properties and markedly improved in storage stability. Was found. The present invention has been completed based on these findings.

[0010]

According to the present invention, there is provided an alkali-soluble phenol resin (A) having the formula (I)

[0011]

Embedded image Wherein k: 1 or 2. m: 1 or 2. R ^{1 to} R ⁵ each independently represent a halogen atom, a hydroxyl group,
It is an alkyl group, a cycloalkyl group, an alkenyl group, an alkoxy group, an aryl group, or an acyl group, and at least one of them is a hydroxyl group. R ^{6 to} R ⁹ each independently represent a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, an alkoxy group, an aryl group, or an acyl group. R ¹⁰ to R ^14: independently, a halogen atom, a hydroxyl group,
It is an alkyl group, a cycloalkyl group, an alkenyl group, an alkoxy group, an aryl group, or an acyl group, and at least one of them is a hydroxyl group. X: a single bond, -O -, - S -, - SO -, - SO 2 -,
-CO -, - CO ₂ -, alkylene, cyclopentylidene, cyclohexylidene, phenylene,

[0012]

Embedded image (Wherein, R ¹⁵ and R ¹⁶ are each independently a hydrogen atom,
It is an alkyl group, an alkenyl group, an aryl group, or a substituted aryl group. ),

[0013]

Embedded image (Wherein, R ^{17 to} R ²⁰ are each independently a hydrogen atom or an alkyl group, and n is 0 or an integer of 1 to 5), or

[0014]

Embedded image (Wherein, R ^{21 to} R ²⁴ are each independently a hydrogen atom or an alkyl group). A quinonediazidesulfonic acid ester of a polyhydroxy compound having a 4-aromatic skeleton represented by the formula (B):

[0015]

Embedded image [Wherein, R ^{25 to} R ³⁴ each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group, a cycloalkyl group, an alkenyl group, an alkoxy group, an aryl group, or an acyl group; Four are hydroxyl groups. Y: single bond, -O -, - S -, - SO -, - SO 2 -,
-CO -, - CO ₂ -, alkylene or,

[0016]

Embedded image (Wherein, R ³⁵ and R ³⁶ are each independently a hydrogen atom or an alkyl group). Quinonediazidosulfonic acid ester (C) of a polyhydroxy compound having a two-aromatic ring skeleton represented by the following formula, and is obtained by gel permeation chromatography using tetrahydrofuran.
Among the peaks obtained at a detection wavelength of 70 nm, a positive resist composition in which the polymer side from the main peak present in the region where the retention time is 20 minutes or longer is within a range of 40 to 90% of the total peak area. Is provided. Also,
According to the present invention, an alkali-soluble phenol resin (A), a compound of the formula (I)

[0017]

Embedded image Wherein k: 1 or 2. m: 1 or 2. R ^{1 to} R ⁵ each independently represent a halogen atom, a hydroxyl group,
It is an alkyl group, a cycloalkyl group, an alkenyl group, an alkoxy group, an aryl group, or an acyl group, and at least one of them is a hydroxyl group. R ^{6 to} R ⁹ each independently represent a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, an alkoxy group, an aryl group, or an acyl group. R ¹⁰ to R ^14: independently, a halogen atom, a hydroxyl group,
It is an alkyl group, a cycloalkyl group, an alkenyl group, an alkoxy group, an aryl group, or an acyl group, and at least one of them is a hydroxyl group. X: a single bond, -O -, - S -, - SO -, - SO 2 -,
-CO -, - CO ₂ -, alkylene, cyclopentylidene, cyclohexylidene, phenylene,

[0018]

Embedded image (Wherein, R ¹⁵ and R ¹⁶ are each independently a hydrogen atom,
It is an alkyl group, an alkenyl group, an aryl group, or a substituted aryl group. ),

[0019]

Embedded image (Wherein, R ^{17 to} R ²⁰ are each independently a hydrogen atom or an alkyl group, and n is 0 or an integer of 1 to 5), or

[0020]

Embedded image (Wherein, R ^{21 to} R ²⁴ are each independently a hydrogen atom or an alkyl group). A quinonediazidosulfonic acid ester of a polyhydroxy compound having a 4-aromatic skeleton represented by the formula (B):

[0021]

Embedded image [Wherein, R ^{25 to} R ³⁴ each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group, a cycloalkyl group, an alkenyl group, an alkoxy group, an aryl group, or an acyl group; Four are hydroxyl groups. Y: single bond, -O -, - S -, - SO -, - SO 2 -,
-CO -, - CO ₂ -, alkylene or,

[0022]

Embedded image (Wherein, R ³⁵ and R ³⁶ are each independently a hydrogen atom or an alkyl group). Quinonediazidosulfonic acid ester of a polyhydroxy compound having a two-aromatic ring skeleton represented by the formula (C) and a solvent;
By heating at 90 ° C. for 0.5 to 10 hours, the peak obtained at a detection wavelength of 470 nm by gel permeation chromatography using tetrahydrofuran is higher than the main peak present in the region where the retention time is 20 minutes or longer. The molecular side is 40 to
A method for producing a positive resist composition in the range of 90% is provided.

Further, according to the present invention, the weight ratio of the quinonediazidesulfonic acid ester (B) of a polyhydroxy compound having a 4-aromatic ring skeleton and the quinonediazidesulfonic acid ester (C) of a polyhydroxy compound having a 2-aromatic ring skeleton is as follows: Usually 20:80 to 80:20, preferably 70: 3
0:30:70, more preferably 35:65 to 65: 3
5 is provided, and the method for producing the same is provided. In the production method, the quinonediazide sulfonic acid ester (B) and / or (C) is subjected to a heat treatment (10 to 240 ° C. at 40 to 70 ° C.).
Time).

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS <Alkali-Soluble Phenolic Resin> Examples of the alkali-soluble phenol resin (A) used in the present invention include a condensation reaction product of a phenol compound and an aldehyde, and a condensation reaction of a phenol compound and a ketone. Examples include reaction products, vinylphenol-based polymers, isopropenylphenol-based polymers, and hydrogenation products of these phenolic resins. These alkali-soluble phenol resins can be used alone or in combination of two or more. Examples of the phenol compound include monohydric phenols such as phenol, cresol, xylenol, ethylphenol, propylphenol, butylphenol, and phenylphenol; polyhydric phenols such as resorcinol, pyrocatechol, hydroquinone, bisphenol A, phloroglucinol, and pyrogallol And the like.

More specifically, examples of the phenol compound include phenol, o-cresol, m-cresol, p-cresol, 2,3-dimethylphenol,
2,5-dimethylphenol, 3,4-dimethylphenol, 3,5-dimethylphenol, 2,4-dimethylphenol, 2,6-dimethylphenol, 2,3,5
-Trimethylphenol, 2,3,6-trimethylphenol, 2-t-butylphenol, 3-t-butylphenol, 4-t-butylphenol, 2-methylresorcinol, 4-methylresorcinol, 5-methylresorcinol, 4-t- Butyl catechol, 2-methoxyphenol, 3-methoxyphenol, 2-propylphenol, 3-propylphenol, 4-propylphenol, 2-isopropylphenol, 3-isopropylphenol, 4-isopropylphenol, 2-methoxy-5-methyl Phenol, 2-t-butyl-5-
Methylphenol, thymol, isothymol and the like can be mentioned.

Among these phenol compounds, o-
Cresol, m-cresol, p-cresol, 2,3
-Dimethylphenol, 3,4-dimethylphenol,
3,5-dimethylphenol, 2,5-dimethylphenol, 2,3,5-trimethylphenol, and 2,
3,6-trimethylphenol is particularly preferred. These phenol compounds can be used alone or in combination of two or more. Preferred examples include a combination of m-cresol and p-cresol, and a combination of m-cresol, p-cresol, and 3,5-xylenol.

Examples of the aldehydes include formaldehyde (formalin), paraformaldehyde, trioxane, acetaldehyde, propylaldehyde, benzaldehyde, phenylacetaldehyde, α-phenylpropylaldehyde, β-phenylpropylaldehyde, o-hydroxybenzaldehyde, m-hydroxy Benzaldehyde, p-hydroxybenzaldehyde, o-chlorobenzaldehyde, m-chlorobenzaldehyde, p-chlorobenzaldehyde, o-nitrobenzaldehyde, m-nitrobenzaldehyde, p-nitrobenzaldehyde, o-methylbenzaldehyde,
Examples include m-methylbenzaldehyde, p-methylbenzaldehyde, p-ethylbenzaldehyde, pn-butylbenzaldehyde, terephthalaldehyde and the like. Of these, formalin, paraformaldehyde, and hydroxybenzaldehydes are preferred. These aldehydes can be used alone or in combination of two or more. Ketones include, for example, acetone, methyl ethyl ketone, diethyl ketone, diphenyl ketone and the like. These ketones can be used alone or in combination of two or more. The condensation reaction product can be obtained by a conventional method, for example, by reacting a phenol compound and an aldehyde or a phenol compound and a ketone in the presence of an acidic catalyst.

The vinylphenol polymer is selected from a homopolymer of vinylphenol and a copolymer of vinylphenol and a component copolymerizable with vinylphenol. The isopropenylphenol-based polymer is selected from a homopolymer of isopropenylphenol and a copolymer of isopropenylphenol with a copolymerizable component. Examples of the component copolymerizable with vinylphenol or isopropenylphenol include monomers such as acrylic acid, methacrylic acid, styrene, maleic anhydride, maleic imide, vinyl acetate, acrylonitrile, and derivatives thereof. The copolymer can be obtained by copolymerizing each component by a known method. The hydrogenation reaction product of the phenolic resin can be obtained by dissolving the phenolic resin in an organic solvent and performing hydrogenation in the presence of a homogeneous or heterogeneous catalyst according to a conventional method.

The weight average molecular weight (Mw) of the alkali-soluble phenolic resin used in the present invention in terms of polystyrene by gel permeation chromatography (GPC) using a UV254 nm detector is usually 2,2.
000-25,000, preferably 3,500-20,
000. If the weight-average molecular weight of the alkali-soluble phenol resin is too small or too large, the pattern shape, resolution, and developability tend to deteriorate. As the alkali-soluble phenol resin, a resin whose molecular weight and molecular weight distribution are controlled by known means can be used.
As a method of controlling the molecular weight or molecular weight distribution, for example,
A method of crushing a resin and performing solid-liquid extraction with an organic solvent having appropriate solubility, a method of dissolving the resin in a good solvent and dropping it in a poor solvent, and a method of dissolving the resin in a good solvent and dropping a poor solvent And a method of solid-liquid or liquid-liquid extraction.

<Photosensitizer> Quinonediazidesulfonic acid ester (B) In the present invention, two types of photosensitizers are used. Among them, the quinonediazidesulfonic acid ester (B) is a compound of the formula (I) ) Is a polyhydroxy compound having a four-aromatic ring skeleton.

[0031]

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The meaning of each symbol in the formula (I) is as described above. In the formula (I), examples of the halogen atom include chlorine, bromine, fluorine, iodine and the like, and among these, chlorine and bromine are preferable. As the alkyl group, an alkyl group having 1 to 10 carbon atoms is preferable, and an alkyl group having 1 to 6 carbon atoms is more preferable. As the cycloalkyl group, a cycloalkyl group having 3 to 10 carbon atoms is preferable, and a cycloalkyl group having 5 to 8 carbon atoms is more preferable.
As the alkenyl group, an alkenyl group having 2 to 10 carbon atoms is preferable, and an alkenyl group having 2 to 6 carbon atoms is more preferable. As the alkoxy group, an alkoxy group having 1 to 10 carbon atoms is preferable, and an alkoxy group having 1 to 6 carbon atoms is more preferable. As the aryl group, an aryl group having 6 to 15 carbon atoms is preferable. The substituted aryl group has 1 to 1 carbon atoms.
An alkyl group or an aryl group substituted with a halogen atom is preferred. As the acyl group, an acyl group having 1 to 10 carbon atoms is preferable, and an acyl group having 1 to 6 carbon atoms is more preferable. As the alkylene, an alkylene having 1 to 10 carbon atoms is preferable, and an alkylene having 1 to 6 carbon atoms is more preferable. Incidentally, the formula -R ¹⁵ CR ¹⁶ - and -R ¹⁷ CR ¹⁸ -
(CH) _n -R ¹⁹ CR ^20- excludes those overlapping with alkylene. Among the polyhydroxy compounds of the formula (I),
As shown in the following formula (III), it is preferable to use a compound having a hydroxyl group at the ortho position with respect to the methylene bridge of the benzene ring at both ends because high resolution can be obtained.

[0033]

Embedded image (The meaning of each symbol in the formula is the same as described above.)

In formulas (I) and (III), compounds in which one hydroxyl group is bonded to each benzene ring are preferred.
As a substituent other than a hydroxyl group in each benzene ring, an alkyl group having 1 to 6 carbon atoms such as a methyl group and a cycloalkyl group such as a cyclohexyl group are preferable. In particular, R
Particularly preferred are those in which ¹ and R ¹⁰ are hydroxyl groups, R ⁴ and R ¹³ are methyl groups, and R ⁷ and R ⁹ are methyl groups or cyclohexyl groups. X in the linking group is preferably a substituted or unsubstituted alkylene group or a cyclohexylidene group. These compounds are preferred because of their resist performance and ease of synthesis. Formula (I)
As specific examples of the polyhydroxy compound represented by the following, the following compounds can be exemplified.

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The quinonediazidesulfonic acid ester (B) used as a photosensitive agent in the present invention is a quinonediazidesulfonic acid ester of a polyhydroxy compound represented by the formula (I). Examples of the quinonediazidesulfonic acid ester include 1,2-benzoquinonediazide-4-sulfonic acid ester and 1,2-naphthoquinonediazide-4-ester.
Sulfonate, 1,2-naphthoquinonediazide-
Examples thereof include 5-sulfonic acid ester, 2,1-naphthoquinonediazide-4-sulfonic acid ester, 2,1-naphthoquinonediazide-5-sulfonic acid ester, and sulfonic acid esters of other quinonediazide derivatives. Among these, 1,2-quinonediazidesulfonic acid ester is preferable, and 1,2-naphthoquinonediazidesulfonic acid ester is particularly preferable.

The photosensitive agent (B) used in the present invention can be synthesized by an esterification reaction between a polyhydroxy compound represented by the general formula (I) and a quinonediazidesulfonic acid compound. Examples of the quinonediazidesulfonic acid compound include 1,2-benzoquinonediazide-4-sulfonic acid, 1,2-naphthoquinonediazide-4-sulfonic acid, 1,2-naphthoquinonediazide-5-sulfonic acid, and 2,1-naphtho. Quinonediazide-4-sulfonic acid,
O-Quinonediazidesulfonic acid compounds such as 2,1-naphthoquinonediazide-5-sulfonic acid; and other quinonediazidosulfonic acid derivatives.

The quinonediazidesulfonic acid ester (B) used in the present invention is obtained by converting a quinonediazidesulfonic acid compound into sulphonyl chloride with chlorosulfonic acid according to a conventional method, and obtaining the resulting quinonediazidosulphonylchloride and a polyamine represented by the formula (I). It is obtained by a condensation reaction with a hydroxy compound. For example, a predetermined amount of a polyhydroxy compound and 1,2-naphthoquinonediazide-5-sulfonyl chloride is dissolved in a solvent such as dioxane, acetone or tetrahydrofuran, and triethylamine, pyridine, sodium carbonate, sodium hydrogen carbonate, sodium hydroxide or hydroxide is dissolved. A quinonediazidesulfonic acid ester can be prepared by adding and reacting a basic catalyst such as potassium, and washing and drying the obtained product.

In the quinonediazidesulfonic acid ester (B) used in the present invention, the esterification ratio (esterification ratio) of the quinonediazidesulfonic acid compound to the polyhydroxy compound represented by the formula (I) is not particularly limited. No, but 2 of the hydroxyl groups of the polyhydroxy compound
It is in the range of 0-100%, preferably 50-80%, more preferably 55-75%. The esterification ratio can be calculated as a charged molar ratio of quinonediazidesulfonic acid halide (for example, quinonediazidosulfonyl chloride) to the molar equivalent number of hydroxyl groups of the polyhydroxy compound. If the esterification ratio is too low, the pattern shape and the resolution may be degraded. If the ester ratio is too high, the sensitivity may be degraded.

Quinone Diazide Sulfonate (C) In the present invention, two kinds of photosensitizers are used. Among them, the quinone diazide sulfonic acid ester (C) has a polyhydroxy compound serving as a mother nucleus represented by the formula (II). Is a polyhydroxy compound having two aromatic ring skeletons.

[0094]

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The meaning of each symbol in the formula (II) is as described above. In the formula (II), examples of the halogen atom include chlorine, bromine, fluorine, iodine and the like, and among these, chlorine and bromine are preferable. As the alkyl group, an alkyl group having 1 to 10 carbon atoms is preferable, and an alkyl group having 1 to 6 carbon atoms is more preferable. As the cycloalkyl group, a cycloalkyl group having 3 to 10 carbon atoms is preferable, and a cycloalkyl group having 5 to 8 carbon atoms is more preferable.
As the alkenyl group, an alkenyl group having 2 to 10 carbon atoms is preferable, and an alkenyl group having 2 to 6 carbon atoms is more preferable. As the alkoxy group, an alkoxy group having 1 to 10 carbon atoms is preferable, and an alkoxy group having 1 to 6 carbon atoms is more preferable. As the aryl group, an aryl group having 6 to 15 carbon atoms is preferable. The substituted aryl group has 1 to 1 carbon atoms.
An alkyl group or an aryl group substituted with a halogen atom is preferred. As the acyl group, an acyl group having 1 to 10 carbon atoms is preferable, and an acyl group having 1 to 6 carbon atoms is more preferable. As the alkylene, an alkylene having 1 to 10 carbon atoms is preferable, and an alkylene having 1 to 6 carbon atoms is more preferable. The formula -R ³⁵ CR ^36- excludes those overlapping with alkylene.

In the formula (II), the number of hydroxyl groups is preferably 4 or 5, and particularly preferably 4. Further, it is preferable that at least one hydroxyl group is present in each of the two benzene rings of the formula (II). These are preferred because of resist performance and ease of synthesis. Further, as Y of the linking group, a substituted or unsubstituted alkylene group and a carbonyl group (—CO—) are preferable, and those having a carbonyl group are excellent in heat resistance. As specific examples of the polyhydroxy compound represented by the formula (II), the following compounds can be exemplified.

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The quinonediazidesulfonic acid ester (C) used as a photosensitive agent in the present invention is a quinonediazidesulfonic acid ester of a polyhydroxy compound represented by the formula (II). Examples of the quinonediazidesulfonic acid ester include the same as those described above. Among them, 1,2-quinonediazidesulfonic acid ester is preferable, and 1,2-naphthoquinonediazidesulfonic acid ester is particularly preferable. Photosensitive agent (C) used in the present invention
Can be synthesized by an esterification reaction between a polyhydroxy compound represented by the general formula (II) and a quinonediazidesulfonic acid compound. As the synthesis method, the same method as described for the photosensitive agent (B) can be employed. In the quinonediazidesulfonic acid ester (C), the ester ratio of the quinonediazidesulfonic acid compound to the polyhydroxy compound represented by the formula (II) is not particularly limited, but may be 20 to 100% of the hydroxyl groups of the polyhydroxy compound. Preferably it is in the range of 60-99%, more preferably 70-95%. If the esterification ratio is too low, sensitivity and heat resistance may deteriorate, while if it is too high, sensitivity and resolution may deteriorate.

<Phenol Compound> In the positive resist composition of the present invention, a phenol compound (D) can be added as an optional component. The phenol compound has an effect of, for example, promoting the alkali solubility of the alkali-soluble phenol resin and improving the resist characteristics such as sensitivity, resolution, residual film ratio, heat resistance, and pattern shape.

The phenol compound is not particularly limited, but specific examples thereof include monophenols such as p-phenylphenol and p-isopropylphenol; biphenol, 4,4'-dihydroxydiphenyl ether, and 4,4'-dihydroxyphenol. Benzophenone, bisphenol A (manufactured by Honshu Chemical Industry), bisphenol C (manufactured by Honshu Chemical Industry), bisphenol E (manufactured by Honshu Chemical Industry), bisphenol F (manufactured by Honshu Chemical Industry),
Bisphenol AP (Honshu Chemical Industry Co., Ltd.), Bisphenol M (Mitsui Petrochemical Industry Co., Ltd.), Bisphenol P
(Manufactured by Mitsui Petrochemical Industry Co., Ltd.), bisphenol Z (manufactured by Honshu Chemical Industry Co., Ltd.), 1,1-bis (4-hydroxyphenyl) cyclopentane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 9,9- Bis (4-hydroxyphenyl) fluorene, 1,1-bis (5-methyl-
2-hydroxyphenyl) methane, 3,5-dimethyl-
Bisphenols such as 4-hydroxybenzylphenol; 1,1,1-tris (4-hydroxyphenyl) methane, 1,1,1-tris (4-hydroxyphenyl)
Ethane, 1,1-bis (3-methyl-4-hydroxyphenyl) -1- (4-hydroxyphenyl) methane,
1,1-bis (2,5-dimethyl-4-hydroxyphenyl) -1- (2-hydroxyphenyl) methane,
1-bis (3,5-dimethyl-4-hydroxyphenyl) -1- (2-hydroxyphenyl) methane, 2,6
-Bis (5-methyl-2-hydroxybenzyl) -4-
Methylphenol, 2,6-bis (4-hydroxybenzyl) -4-methylphenol, 2,6-bis (3-methyl-4-hydroxybenzyl) -4-methylphenol, 2,6-bis (3,5 -Dimethyl-4-hydroxybenzyl) -4-methylphenol, trisphenol-PA (manufactured by Honshu Chemical Industry Co., Ltd.), trisphenol-TC
(Honshu Chemical Industry Co., Ltd.) and other trisphenols;
1,2,2-tetrakis (4-hydroxyphenyl) ethane, 1,1,2,2-tetrakis (3-methyl-4-
Hydroxyphenyl) ethane, 1,1,3,3- (4-
Hydroxyphenyl) propane, 1,1,5,5-tetrakis (4-hydroxyphenyl) pentane, α, α,
α ', α'-tetrakis (4-hydroxyphenyl)-
3-xylene, α, α, α ′, α′-tetrakis (4-
(Hydroxyphenyl) -3-xylene, α, α, α ′,
tetrakisphenols such as α′-tetrakis (3-methyl-4-hydroxyphenyl) -3-xylene, α, α, α ′, α′-tetrakis (3-methyl-4-hydroxyphenyl) -4-xylene; And the like. These phenol compounds can be used alone or in combination of two or more.

<Other Components> In order to improve developability, storage stability, heat resistance and the like, styrene and an unsaturated acid (for example, Acrylic acid, methacrylic acid, maleic anhydride), a copolymer of alkene and maleic anhydride, polyvinyl alcohol, polyvinylpyrrolidone,
Rosin, shellac and the like can be added. The addition amount of such a polymer is usually in the range of 0 to 50 parts by weight, preferably 5 to 20 parts by weight based on 100 parts by weight of the alkali-soluble phenol resin. Further, the positive resist composition of the present invention may contain a compatible additive such as a surfactant, a storage stabilizer, a sensitizer, a striation inhibitor, and a plasticizer, if necessary. it can.

Examples of the surfactant include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether and polyoxyethylene oleyl ether; polyoxyethylene octyl phenyl ether and polyoxyethylene nonyl phenol ether. Polyoxyethylene aryl ethers such as polyethylene glycol dilaurate, ethylene glycol distearate, etc .; brand names EFTOP EF301, EF303, EF352 (manufactured by Shin-Akita Chemical Co., Ltd.); brand names Megafax F171, F172 , F
173, F177 (manufactured by Dainippon Ink and Chemicals), trade names Florado FC430 and FC431 (manufactured by Sumitomo 3M Limited),
Trade name Asahi Guard AG710, trade name Surflon
S-382, SC-101, SC-102, SC-10
3, SC-104, SC-105, SC-106 (manufactured by Asahi Glass Co., Ltd.); fluorinated surfactants; organosiloxane polymer KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.); acrylic acid-based or methacrylic acid-based (co) polymer Polyflow N
o. 75, no. 95 (manufactured by Kyoeisha Yushi Kagaku Kogyo KK). The amount of these surfactants is usually 2 parts by weight or less, preferably 1 part by weight or less, per 100 parts by weight of the solid content of the positive resist composition.

<Solvent> The positive resist composition of the present invention is usually used as a solution dissolved in a solvent (E) for coating on a substrate to form a resist film. Alkali-soluble phenolic resin, photosensitizer, phenolic compound,
Each component such as other additives is used by dissolving it in a solvent in an amount sufficient to uniformly dissolve these components.

Specific examples of the solvent used in the present invention include ketones such as acetone, methyl ethyl ketone, cyclopentanone and cyclohexanone; alcohols such as n-propyl alcohol, isopropyl alcohol, n-butyl alcohol and cyclohexanol; Ethers such as glycol dimethyl ether, ethylene glycol diethyl ether and dioxane; alcohol ethers such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether; propyl formate, butyl formate, propyl acetate, butyl acetate, methyl propionate, and ethyl propionate; Methyl butyrate,
Esters such as ethyl butyrate; methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate,
Monooxycarboxylic esters such as methyl methoxypropionate, ethyl 2-methoxypropionate, methyl 2-ethoxypropionate, and ethyl 2-ethoxypropionate; cellosolve acetate, methyl cellosolve acetate, ethyl cellosolve acetate, propyl cellosolve acetate, butyl cellosolve Cellosolve acetates such as acetate; propylene glycols such as propylene glycol, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, and propylene glycol monobutyl ether; diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether Halogenated hydrocarbons such as trichlorethylene; diethylene glycols such as toluene, aromatic hydrocarbons such as xylene; dimethylacetamide, dimethylformamide, polar solvents such as N- methyl-acetamide; and the like. These solvents can be used alone or in combination of two or more.

Among these solvents, from the viewpoint of storage stability of the positive resist composition, ethyl 2-hydroxypropionate (that is, ethyl lactate: hereinafter abbreviated as “EL”) is preferable. EL can be used alone, but may be used in combination with another solvent. From the viewpoint of storage stability, the weight ratio of EL / other solvent is usually 100: 0.
５０50: 50, preferably 100: 0 to 70:30.

<Positive resist composition and method for producing the same> The positive resist composition of the present invention comprises, as essential components,
It contains an alkali-soluble phenol resin (A), a quinonediazidesulfonic acid ester (B), and a quinonediazidesulfonic acid ester (C), and if necessary, other optional components such as a phenol compound (D). These components are used and stored as a resist solution in which a solvent is uniformly dissolved in a solvent. The quinone diazide sulfonic acid ester (B) and the quinone diazide sulfonic acid ester (C) of the photosensitizer are usually 1 to 100 parts by weight in total (B + C) based on 100 parts by weight of the alkali-soluble phenol resin (A). Is used in a proportion of 3 to 50 parts by weight, more preferably 10 to 40 parts by weight. If the compounding ratio of the photosensitive agent is too small, it is difficult to obtain a sufficient residual film ratio after development, and the resolution may be reduced. If the compounding ratio of the photosensitive agent is too large, the heat resistance will be reduced.

Quinonediazidesulfonic acid ester (B)
Weight ratio of quinonediazidesulfonic acid ester (C) is usually 20:80 to 80:20, preferably 70:80.
30-30: 70, more preferably 35: 65-65:
The range is 35. When the use ratio of the quinonediazidesulfonic acid ester (B) is too small, the effect of improving the resolution and the pattern shape becomes small. If the proportion of the quinonediazide sulfonic acid ester (C) is too small, the effect of improving sensitivity and heat resistance is reduced. When the use ratio of these two is within the above range, sensitivity, resolution, pattern shape, and heat resistance can be highly balanced, which is preferable. Further, by using both of them, other resist characteristics such as a residual film ratio and an exposure margin are also good. The mixing ratio of the phenol compound (D) is usually from 0 to 5 based on 100 parts by weight of the alkali-soluble resin (A).
0 parts by weight, preferably 1 to 40 parts by weight, more preferably 3 to 30 parts by weight. The amounts of the other additives are as described above. In addition, the positive resist of the present invention may contain a small amount of other photosensitizer (30% by weight or less of all photosensitizer components) as necessary.

The positive resist composition of the present invention was measured for gel permeation chromatography (GPC) using tetrahydrofuran (THF) at 470 nm.
In the peaks obtained at the detection wavelengths of, the area on the polymer side (polymer component) from the main peak existing in the region where the retention time is 20 minutes or longer is 4% of the total peak area.
It is in the range of 0-90%. The area ratio of the polymer component by GPC measurement is preferably 50 to 80%, and is often in the range of 50 to 70%. If this area ratio is too small, the effect of improving storage stability is small, and fine particles that are insoluble in a solvent during long-term storage tend to be generated. If this area ratio is too large, there is a possibility that the resist characteristics may be deteriorated.

As a method for adjusting the area ratio of the polymer component by GPC measurement within the above range, for example, (1) after preparing photosensitive agent B or photosensitive agent C, one or both of these photosensitive agents are prepared. A heat treatment at 40 to 70 ° C., preferably 45 to 65 ° C., usually for 10 to 240 hours, preferably 24 to 100 hours, more preferably 36 to 72 hours, (2) an alkali-soluble phenol resin, After dissolving the photosensitizer and other components in a solvent to prepare a resist solution, the resist solution is usually 40 to
90 ° C, preferably 50-80 ° C, more preferably 60 ° C
At a temperature of not less than 75 ° C., usually 0.5 to 24 hours,
Preferably 1 to 10 hours, more preferably 1 to 6 hours,
A method of performing a heat treatment, (3) a method of combining these methods, and the like. It is presumed that these heat treatments modify the photosensitizer component and increase the proportion of the polymer component, thereby improving the storage stability.

Among these methods, the method including the step of preparing a resist solution and then subjecting the resist solution to a heat treatment [methods (2) and (3)] is preferable because of easy preparation. In some cases, it is also possible to use a polyhydroxy compound containing a dimer or trimer of the polyhydroxy compound represented by the formula (I) or (II) to increase the proportion of the high molecular weight component. . The resist solution can be formed on a substrate such as a silicon wafer by applying the resist solution by a conventional method and then removing the solvent by drying. As a coating method at this time, spin coating is particularly preferable. Usually, various layers to be processed are formed on the substrate. As an exposure source used in the exposure step for forming a pattern on the resist film thus obtained,
UV light, deep UV light, KrF excimer laser light, X-ray,
An electron beam source such as an electron beam may be used. When heat treatment (post-exposure bake) is performed after exposure, sensitivity, residual film ratio, resolution,
It is preferable because heat resistance can be improved.

<Developer> In the positive resist composition of the present invention, an alkaline aqueous solution can be used as a developer in the developing step. Examples of the aqueous alkali solution include aqueous solutions of inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium silicate, and ammonia; aqueous solutions of primary amines such as ethylamine and propylamine;
Aqueous solutions of secondary amines such as diethylamine and dipropylamine; aqueous solutions of tertiary amines such as trimethylamine and triethylamine; aqueous solutions of alcoholamines such as diethylethanolamine and triethanolamine; tetramethylammonium hydroxide, tetraethylammonium hydroxide; Aqueous solutions of quaternary ammonium hydroxides such as trimethylhydroxymethylammonium hydroxide, triethylhydroxymethylammonium hydroxide and trimethylhydroxyethylammonium hydroxide; and the like. If necessary, for example, a water-soluble organic solvent such as methanol, ethanol, propanol, and ethylene glycol, a surfactant, and a dissolution inhibitor for a resin can be added to the alkaline aqueous solution.

[0129]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Synthesis Examples, Examples, and Comparative Examples, but the present invention is not limited to only these Examples. The parts and percentages in these examples are on a weight basis unless otherwise specified. The resist evaluation method in the following examples and comparative examples is as follows. (1) Sensitivity 0.81 μm 1: 1 line & space is the exposure energy that can be formed according to the design dimensions.
And expressed as a relative value (relative sensitivity). (2) Resolution The critical resolution (μm) under the above exposure conditions is shown. (3) Pattern Shape The silicon wafer on which the resist pattern was formed was cut from the direction perpendicular to the line pattern, and the result of observation with an electron microscope from the cross-sectional direction of the pattern was shown. A pattern having a side wall of 80 ° C. or higher with respect to the substrate was evaluated as “good”, and a pattern having a side wall lower than 80 ° C. was determined as “tapered”.

(4) Heat Resistance After the silicon wafer on which the resist pattern was formed under the above exposure conditions was heated on a hot plate at a predetermined temperature for 300 seconds, a change in the shape of the 100 μm line pattern was observed with an electron microscope. The temperature at which the pattern edge is not completely rounded is shown as an index of heat resistance. (5) Storage stability The prepared positive resist solution was allowed to stand at 23 ° C., and the precipitate in the solution after storage for 3 months was analyzed using an automatic particle analyzer KL-20 manufactured by Rion Co., Ltd. 0.25
The number of undissolved particles having a size of not less than μm was measured. The number of undissolved particles increased by 10 or less was evaluated as ○, and the number exceeding 10 was evaluated as x. Except that the storage temperature was changed to 35 ° C., and the number of undissolved particles after storage for 2 months was measured, the measurement was performed under the same conditions as in all cases, and evaluation was performed in the same manner.

[Synthesis Example 1] (Synthesis of Novolak Resin A1) A 2 liter flask equipped with a cooling pipe and a stirrer was put into a flask.
m-cresol 306 g, p-cresol 83 g, 3,
147 g of 5-xylenol, paraformaldehyde 10
8 g, and 1.8 g of oxalic acid dihydrate, 95-1
The reaction was performed for 2 hours while maintaining the temperature at 00 ° C. Thereafter, water was distilled at a temperature of 100 to 105 ° C. for 2 hours, and further, the pressure was reduced to 10 mmHg while the temperature was raised to 180 ° C., and after removing unreacted monomers and water, the temperature was returned to room temperature. 480 g was recovered. The polystyrene-equivalent weight average molecular weight (Mw) of this novolak resin by GPC was 4,200. 300 g of the above novolak resin, 30 g of propylene glycol monomethyl ether acetate, and 900 g of toluene were added, and dissolved by heating to 80 ° C. Equipped with a dropping funnel, 8
Toluene 1,800 at a temperature controlled at 0 to 85 ° C
g was added dropwise and heated for an additional hour. Slowly cool to room temperature,
It was left still for one hour. After removing the supernatant liquid of the precipitated resin by decantation, 900 g of ethyl 2-hydroxypropionate (ethyl lactate) was added,
The mixture was heated to 100 ° C. at 100 mmHg to remove residual toluene, and a novolak resin A1 was obtained. Mw of the novolak resin A1 was 6,500.

[Synthesis Example 2] (Synthesis of Novolak Resin A2) A 2 liter flask equipped with a cooling pipe and a stirrer was placed in a flask.
178 g of m-cresol, 222 g of p-cresol,
100 g of 3,5-xylenol, 68.8 g of paraformaldehyde, 128.8 g of salicylaldehyde, and 3
4.0 g of 5% hydrochloric acid was added, and the mixture was reacted for 100 minutes while maintaining the temperature at 90 to 100 ° C. After this, 100 to 10
Distill the water at a temperature of 5 ° C. for 30 minutes,
The pressure was reduced to 10 mmHg while increasing the temperature to 0 ° C., and after removing unreacted monomers and water, the temperature was returned to room temperature, and 400 g of novolak resin A2 was recovered. Mw of this novolak resin A2 was 4,700.

Synthesis Example 3 (Synthesis of Novolak Resin A3) To 300 g of the novolak resin obtained in Synthesis Example 2, 54 g of ethyl lactate and 360 g of toluene were added, and the mixture was heated to 80 ° C. and dissolved. A dropping funnel was attached, and 2,040 g of toluene was added dropwise while controlling the temperature at 80 to 85 ° C., and the mixture was further heated for 1 hour. The mixture was gradually cooled to room temperature and left still for 1 hour. After removing the supernatant liquid of the precipitated resin by decantation, 900 g of ethyl lactate was added, and 1
The mixture was heated to 100 ° C. at 00 mmHg to remove residual toluene, and a novolak resin A3 was obtained. This novolak resin A
Mw of 3 was 6,700.

[Synthesis Example 4] (Synthesis of Novolak Resin A4) A 2 liter flask equipped with a cooling pipe and a stirrer was placed in a flask.
m-cresol 318 g, p-cresol 255 g,
160 g of 2,3,5-trimethylphenol, 138 g of paraformaldehyde, and 2.4 g of oxalic acid dihydrate
, And the mixture was reacted for 2 hours while maintaining the temperature at 95 to 100 ° C. Thereafter, water is distilled at a temperature of 100 to 105 ° C. for 2 hours, and further, the pressure is reduced to 10 mmHg while the temperature is raised to 180 ° C., and after removing unreacted monomers and water, the mixture is returned to room temperature and collected. 62 novolak resin
0 g was obtained. Mw of this novolak resin was 3,900. 380 g of the novolak resin, 38 g of propylene glycol monomethyl ether acetate, and 380 g of toluene were added, and the mixture was heated to 80 ° C. and dissolved. A dropping funnel was attached, and 3,000 g of toluene was added dropwise while controlling the temperature at 80 to 85 ° C., and the mixture was further heated for 1 hour.
The mixture was gradually cooled to room temperature and left still for 1 hour. After removing the supernatant liquid of the precipitated resin by decantation, 600 g of ethyl lactate was added, and 10 ml at 100 mmHg.
The mixture was heated to 0 ° C. to remove residual toluene, and a novolak resin A4 was obtained. The Mw of this novolak resin A4 is 6,0
00.

[Synthesis Example 5] (Synthesis of Novolak Resin A5) A 2-liter flask equipped with a cooling pipe and a stirrer was placed in a flask.
m-cresol 318 g, p-cresol 255 g,
80 g of 2,3,5-trimethylphenol, 127 g of paraformaldehyde and 2.2 g of oxalic acid dihydrate were added, and the mixture was reacted for 2 hours while maintaining the temperature at 95 to 100 ° C. Thereafter, water is distilled at a temperature of 100 to 105 ° C. for 2 hours, and the temperature is further increased to 180 ° C. for 10 hours.
After reducing the pressure to mmHg to remove unreacted monomers and water, the temperature was returned to room temperature, and 580 g of a novolak resin was recovered. Mw of the novolak resin was 4,200. 380 g of the novolak resin, 38 g of propylene glycol monomethyl ether acetate, and 380 g of toluene were added, and the mixture was heated to 80 ° C. and dissolved. A dropping funnel was attached, and 3,000 g of toluene was added dropwise while controlling the temperature at 80 to 85 ° C., and the mixture was further heated for 1 hour. The mixture was gradually cooled to room temperature and left still for 1 hour. After removing the supernatant liquid of the precipitated resin by decantation,
Add 600 g of ethyl lactate and 100 mmHg at 100 ° C
To remove the residual toluene, and remove the novolak resin A5
I got The Mw of the novolak resin A5 is 6,200
Met.

[Synthesis Example 6] <Synthesis of Photosensitive Agent B1> A compound of the above formula (b-7) was used as a polyhydroxy compound, and 1,2-naphthoquinonediazide was used in an amount corresponding to 70 mol% of the hydroxyl groups. 5-Sulfonyl chloride was dissolved in acetone to make a 10% solution. 20
While controlling the temperature at 〜25 ° C., 1.2 equivalents of triethylamine of 1,2-naphthoquinonediazide-5-sulfonic acid chloride was added dropwise over 30 minutes, and the reaction was completed for another 4 hours. The precipitated salt was separated by filtration and poured into a 0.2% aqueous solution of oxalic acid 10 times the amount of the reaction solution. The precipitated solid was filtered, washed with ion-exchanged water, and dried to obtain a quinonediazidesulfonic acid ester-based photosensitizer B1.

[Synthesis Example 7] <Photosensitizers B2 to B3 and Photosensitizers C1 to C4> The type of polyhydroxy compound or the molar ratio of 1,2-naphthoquinonediazide-5-sulfonic acid chloride to the number of hydroxyl groups was changed. Synthesis Example 6
According to the same formulation as in the above, photosensitive agents B2 to B3 and photosensitive agents C1 to C4 were synthesized. The type and charge ratio of the polyhydroxy compound used are shown in Table 1.

[Synthesis Example 8] <Photosensitizers C5 to C6> Synthesis was performed except that the kind of the polyhydroxy compound or the charged molar ratio of 1,2-naphthoquinonediazide-5-sulfonic acid chloride to the number of hydroxyl groups was changed. Example 6
A photosensitizer was synthesized according to the same formulation as described above. The type of the polyhydroxy compound used and the charging ratio are shown in Table 1.
Thereafter, the obtained photosensitizer was thermally denatured in a heated vacuum dryer having an internal temperature of 50 ° C. for 48 hours to obtain photosensitizers C5 and C6.

Example 1 90 parts of an alkali-soluble phenol resin (novolak resin A1) and 15 parts of photosensitive agent B3
Parts, 9 parts of photosensitive agent C3, and a phenol compound [D3:
1,1-bis (4-hydroxyphenol) cyclohexane] was dissolved in a solvent, and the amount of the solvent was adjusted so that the film could be coated at a film pressure of 1.17 μm. As the solvent,
A mixed solvent of 383 parts of ethyl 2-hydroxypropionate (E1) and 67 parts of butyl acetate (E2) was used. Thereafter, the obtained solution was subjected to a heat treatment at 72 ° C. for 240 minutes. The solution after the heat treatment was filtered through an ultrahigh molecular weight polyethylene filter (UPE filter) having a pore size of 0.1 μm to prepare a resist solution.

GPC polymer area ratio The resist solution thus prepared was subjected to GPC
When measured at a detection wavelength of 470 nm, the specific component having a retention time of 20 minutes or longer and located on the polymer side from the peak of the main component is quantified by the vertical division method, and the area ratio of the specific polymer component to all components is determined. Was calculated. After applying the resist solution on a silicon wafer with a spin coater,
Pre-baking was performed on a hot plate at 90 ° C. for 60 seconds to form a resist film having a film pressure of 1.17 μm. The silicon wafer having the resist film formed thereon is placed on an i-line stepper NSR1.
Exposure was performed using 755i7A (Nikon Corporation, NA = 0.50) and a test reticle while changing the exposure time. Next, the silicon wafer on which the resist film was formed was exposed to a hot plate at 110 ° C. for 60 seconds and baked (Post Exposure Bake; PEB), and then padded with a 2.38% aqueous tetraammonium hydroxide solution at 23 ° C. for 1 minute. A positive pattern was formed by development according to the following method. The silicon wafer on which this pattern was formed was taken out, and the sensitivity, the resolving power, the pattern shape, and the heat resistance were observed with an electron microscope, and the storage stability was evaluated. Table 1 shows the composition of the positive resist composition.
Table 3 shows the evaluation results of the resist performance.

[Examples 2 to 8 and Comparative Examples 1 to 5] Table 1
As shown in Table 2, and in the same manner as in Example 1, except that the composition of the positive resist composition was changed and the heat treatment time was changed. Tables 1 and 2 show the composition and heat treatment conditions of each positive resist composition, and Table 3 shows the evaluation results of the resist performance.

[0142]

[Table 1]

(Footnotes) A1 to A5: Novolak resins AB1 to B3 synthesized in Synthesis Examples 1 to 5: Photosensitive agents A1 to C5 synthesized in Synthesis Examples 6 to 7: Photosensitive agents synthesized in Synthesis Examples 7 to 8 C D1: Trisphenol PA (manufactured by Honshu Chemical) D2: 1,1-bis (3,5-dimethyl-4-hydroxyphenol) -1- (2-hydroxyphenol) methane D3: 1,1-bis ( 4-hydroxyphenol) cyclohexane E1: ethyl 2-hydroxypropionate E2: butyl acetate E3: propylene glycol monomethyl ether acetate

[0144]

[Table 2] (Footnotes) The symbols in the table are the same as those in Table 1.

[0145]

[Table 3]

As is clear from Tables 1 to 3, the sensitivity (relative sensitivity),
A high-performance positive resist composition having excellent resolution (resolution), pattern shape, and heat resistance can be obtained. Further, by adjusting the area ratio of the polymer component by GPC measurement to 40 to 90%, the storage stability at ordinary temperature and high temperature can be remarkably improved. On the other hand, when only the photosensitive agent B was used (Comparative Examples 2 to 3), the sensitivity and the heat resistance were insufficient, and the storage stability was also insufficient. When only the photosensitive agent C was used (Comparative Example 1),
The resolution and the pattern shape are insufficient. When the area ratio of the polymer component is small by GPC measurement (Comparative Examples 4 to 5)
Have insufficient storage stability over a long period of time. Therefore, by using the photosensitive agent B and the photosensitive agent C together, a kind of synergistic effect can be achieved, and by adjusting the area ratio of the polymer component by GPC measurement to 40 to 90%,
The storage stability at normal temperature and high temperature can be remarkably improved. Further, storage stability can be enhanced by using ethyl 2-hydroxypropionate alone or in combination with another solvent as a solvent.

[0147]

According to the present invention, there is provided a positive resist composition in which sensitivity, resolution, pattern shape, and heat resistance are highly balanced and excellent in storage stability, and a method for producing the same. The positive resist composition of the present invention is particularly useful as a photoresist material for fine processing in the production of semiconductor devices, magnetic bubble memory devices, integrated circuits, and the like.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H025 AA00 AA01 AA02 AA03 AA10 AB16 AB20 AC01 AC04 AC06 AC08 AD03 BE01 CB28 CB45 CB52 CB56 4H006 AA03 AB76

Claims (2)

[Claims] 1. An alkali-soluble phenol resin (A),
Formula (I) Wherein k: 1 or 2. m: 1 or 2. R ^{1 to} R ⁵ each independently represent a halogen atom, a hydroxyl group,
It is an alkyl group, a cycloalkyl group, an alkenyl group, an alkoxy group, an aryl group, or an acyl group, and at least one of them is a hydroxyl group. R ^{6 to} R ⁹ each independently represent a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, an alkoxy group, an aryl group, or an acyl group. R ¹⁰ to R ^14: independently, a halogen atom, a hydroxyl group,
It is an alkyl group, a cycloalkyl group, an alkenyl group, an alkoxy group, an aryl group, or an acyl group, and at least one of them is a hydroxyl group. X: a single bond, -O -, - S -, - SO -, - SO 2 -,
—CO—, —CO ₂ —, alkylene, cyclopentylidene, cyclohexylidene, phenylene, (Wherein, R ¹⁵ and R ¹⁶ are each independently a hydrogen atom,
It is an alkyl group, an alkenyl group, an aryl group, or a substituted aryl group. ), Embedded image (Wherein, R ^{17 to} R ²⁰ are each independently a hydrogen atom or an alkyl group, and n is 0 or an integer of 1 to 5), or (Wherein, R ^{21 to} R ²⁴ are each independently a hydrogen atom or an alkyl group). A quinonediazidosulfonic acid ester (B) of a polyhydroxy compound having a 4-aromatic ring skeleton represented by the formula (II): [Wherein, R ^{25 to} R ³⁴ each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group, a cycloalkyl group, an alkenyl group, an alkoxy group, an aryl group, or an acyl group; Four are hydroxyl groups. Y: single bond, -O -, - S -, - SO -, - SO 2 -,
—CO—, —CO ₂ —, alkylene, or (Wherein, R ³⁵ and R ³⁶ are each independently a hydrogen atom or an alkyl group). Quinonediazidosulfonic acid ester (C) of a polyhydroxy compound having a two-aromatic ring skeleton represented by the following formula, and is obtained by gel permeation chromatography using tetrahydrofuran.
Among the peaks obtained at a detection wavelength of 70 nm, the positive resist composition in which the polymer side from the main peak present in the region where the retention time is 20 minutes or more is in the range of 40 to 90% of the total peak area. . 2. An alkali-soluble phenol resin (A),
Formula (I) Wherein k: 1 or 2. m: 1 or 2. R ^{1 to} R ⁵ each independently represent a halogen atom, a hydroxyl group,
It is an alkyl group, a cycloalkyl group, an alkenyl group, an alkoxy group, an aryl group, or an acyl group, and at least one of them is a hydroxyl group. R ^{6 to} R ⁹ each independently represent a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, an alkoxy group, an aryl group, or an acyl group. R ¹⁰ to R ^14: independently, a halogen atom, a hydroxyl group,
It is an alkyl group, a cycloalkyl group, an alkenyl group, an alkoxy group, an aryl group, or an acyl group, and at least one of them is a hydroxyl group. X: a single bond, -O -, - S -, - SO -, - SO 2 -,
—CO—, —CO ₂ —, alkylene, cyclopentylidene, cyclohexylidene, phenylene, (Wherein, R ¹⁵ and R ¹⁶ are each independently a hydrogen atom,
It is an alkyl group, an alkenyl group, an aryl group, or a substituted aryl group. ), (Wherein, R ^{17 to} R ²⁰ are each independently a hydrogen atom or an alkyl group, and n is 0 or an integer of 1 to 5), or (Wherein, R ^{21 to} R ²⁴ are each independently a hydrogen atom or an alkyl group). A quinonediazidesulfonic acid ester of a polyhydroxy compound having a four-aromatic ring skeleton (B) represented by the formula (II): [Wherein, R ^{25 to} R ³⁴ each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group, a cycloalkyl group, an alkenyl group, an alkoxy group, an aryl group, or an acyl group; Four are hydroxyl groups. Y: single bond, -O -, - S -, - SO -, - SO 2 -,
—CO—, —CO ₂ —, alkylene, or (Wherein, R ³⁵ and R ³⁶ are each independently a hydrogen atom or an alkyl group). Quinonediazidosulfonic acid ester of a polyhydroxy compound having a two-aromatic ring skeleton represented by the formula (C) and a solvent;
By heating at 90 ° C. for 0.5 to 10 hours, the peak obtained at a detection wavelength of 470 nm by gel permeation chromatography using tetrahydrofuran is higher than the main peak present in the region where the retention time is 20 minutes or longer. The molecular side is 40 to
A method for producing a positive resist composition within the range of 90%.