JP2000075477A - Positive resist composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a good pattern of high resolution and high contrast by electron beams and to obtain high film remaining rate and dimensional controlling property by incorporating an alkali-soluble resin, quinonediazide sulfonic acid ester compd. and specified org. acid polycyclic aromatic ester compd. SOLUTION: This compsn. contains an alkali-soluble resin, quinonediazide sulfonic acid ester compd. and aromatic ester compd. having ester structure- contg. aromatic groups expressed by the formula. In the formula, R' and R" are independently hydrogen atoms or 1-6C alkyl groups, R is independently a hydrogen atom, 1-6C alkyl group or alkoxy group which may be branched, 2-7C alkenyl group, aryl group or aryloxy group which may be branched, X is a halogen atom, nitro group or cyano group, and p, q satisfy 0<p, 0<=q and 0<(p+q)<=4. The obtd. compsn. is especially suitable for the production of a photomask produced by using electron beams.

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, and more particularly, to a positive resist composition for fine processing required for manufacturing semiconductor devices, magnetic bubble memory devices, integrated circuits, and liquid crystal displays (LCDs). .

[0002]

2. Description of the Related Art When manufacturing a semiconductor device, a resist is applied to the surface of a silicon wafer to form a photosensitive film, a latent image is formed by irradiating light or radiation, and then developed to form a negative or positive image. An image is obtained by a lithography technique for forming the image. By the way, IC, LSI and VLSI
As semiconductors become more highly integrated, denser, smaller, and faster, demands for fine processing of devices increase, and a technology for forming a fine pattern of 0.5 μm or less is now required. Lithography apparatuses are roughly classified into a method of transferring a mask pattern using light, X-rays, and the like, and a method of drawing using a beam scan of electrons and ions. The latter drawing method has low throughput because it is a sequential process,
Since patterns can be created and changed quickly and easily, masks, reticles, ASICs (Applic
ation Specific Integrated
(Circuit) or a device prototype at the research and development stage.

[0003] A resist pattern necessary for manufacturing a mask pattern or a circuit pattern such as an ASIC is formed by forming a radiation-sensitive resist film on a substrate and irradiating the film with a finely focused ion beam such as an electron beam. And then developing using a developing solution compatible with the resist used.

Hitherto, polymers such as PMMA (polymethyl methacrylate) and poly-α-methylstyrene have been known as radiation-sensitive positive resists used in a drawing system. In this case, an organic solvent is used as a developing solution. Solvent is used. However, PMMA has a disadvantage that it has high resolution but low sensitivity.
Further, since an organic solvent is used for the developer, there are problems such as deterioration of working environment and waste liquid treatment. For this reason,
In recent years, development of a photoresist composition that can be developed with an aqueous alkali solution using an alkali-soluble resin and a quinonediazidesulfonic acid ester-based photosensitizer has been developed for the production of a photomask. However, such a photoresist composition generally has low sensitivity to ionizing radiation (mainly, electron beam) and is poor in practicality, and when used at practical sensitivity, the resolution, pattern shape, and dimensional controllability are deteriorated. There was a problem of deterioration.

[0005]

Based on such prior art, the present inventors have conducted intensive studies to solve the above-mentioned problems. As a result, in a resist composition containing an alkali-soluble resin and a quinonediazidesulfonic acid ester-based photosensitizer, By containing certain organic acid polycyclic aromatic ester compounds, it is possible to form very good patterns with high resolution, high contrast, and high dimensional controllability even for electron beams. It has been found that a positive resist composition excellent in the above can be obtained, and the present invention has been completed based on this finding.

[0006]

Thus, according to the present invention, there is provided an alkali-soluble resin, a quinonediazide sulfonic acid ester compound, and an aromatic ester compound having an ester group-containing aromatic group represented by the following general formula (1). A positive resist composition is provided.

Embedded image (In the formula (1), R ′ and R ″ are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and R is independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may be branched. X is a halogen atom, a nitro group or a cyano group, or an alkoxy group, an alkenyl group, an aryl group or an aryloxy group having 2 to 7 carbon atoms which may be branched, and 0 <p, 0 ≦ q. 0 <(p + q) ≦ 4
It is. )

[0007] Among them, a compound in which the aromatic ester compound is a compound represented by the following general formula (2) or (3) is mentioned as a particularly preferred example.

[0008]

Embedded image (In the formula (2), R ¹ and R ² are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and R ¹² is independently a hydrogen atom and may be branched having 1 to 6 carbon atoms. X ¹ is a halogen atom, a nitro group or a cyano group, which is an alkyl group or an alkoxy group, an alkenyl group having 2 to 7 carbon atoms which may be branched, an aryl group, or an aryloxy group, and 0 <p1,0. ≦ q1 and 0 <(p
1 + q1) ≦ 4. )

[0009]

Embedded image(In the formula (3), R¹~ R¹¹Are independently hydrogen sources
Or an alkyl group having 1 to 6 carbon atoms,¹²~
R^FifteenAre each independently a hydrogen atom, a carbon number of 1 to 6
Alkyl or alkoxy groups which may be branched,
An alkenyl group or an aryl group having a prime number of 2 to 7, which may be branched;
Or an aryloxy group, X¹~ X ⁴Is halo
Gen atom, nitro group or cyano group. 0 <
p1, p2, p3, p4, and 0 ≦ q1, q2, q
3, q4, (p1 + q1), (p2 + q2),
(P3 + q3) and (p4 + q4) are each independently
0-4, at least one of which is greater than 0
4 or less. )

Hereinafter, the present invention will be described in detail. (1) Alkali-soluble resin As the alkali-soluble resin used in the present invention, a general alkali-soluble phenol resin is used. Alkali-soluble phenolic resins include, for example, condensation reaction products of phenols and aldehydes (novolak resins), condensation reaction products of phenols and ketones, vinylphenol polymers, isopropenylphenol polymers, and the like. Examples include a hydrogenation reaction product of a phenol resin, and it is particularly preferable to use a novolak resin.

Specific examples of the phenols used here include phenol, o-cresol, m-cresol, p-cresol and p-cresol.
-Cresol, 2,3-xylenol, 2,4-xylenol, 3,5-xylenol, 2,6-xylenol, 1,2,3-trimethylphenol, 2,3,4
-Trimethylphenol, 2,3,5-trimethylphenol, o-ethylphenol, m-ethylphenol, p-ethylphenol, o-propylphenol,
m-propylphenol, p-propylphenol, o
Monovalent such as -butylphenol, m-butylphenol, p-butylphenol, o-phenylphenol, m-phenylphenol, p-phenylphenol, o-methoxyphenol, m-methoxyphenol, p-methoxyphenol, 3-methylmethoxyphenol And polyhydric phenols such as resorcinol, pyrocatechol, hydroquinone, bisphenol A, phloroglucinol and pyrogallol.

Specific examples of aldehydes include formaldehyde, paraformaldehyde, benzaldehyde,
Examples thereof include hydroxybenzaldehyde and terephthalaldehyde. Specific examples of ketones include acetone, methyl ethyl ketone, diethyl ketone, diphenyl ketone, acetaldehyde, and hydroxyacetaldehyde. These condensation reaction products can be obtained by a conventional method, for example, by reacting a phenol with an aldehyde or a ketone in the presence of an acidic catalyst.

The vinylphenol-based polymer is selected from a homopolymer of vinylphenol or isopropylphenol and a copolymer of vinylphenol or isopropylphenol with a copolymerizable component. Specific examples of the copolymerizable component include acrylic acid, methacrylic acid, styrene, maleic anhydride, maleic imide, vinyl acetate,
Acrylonitrile and derivatives thereof are exemplified.
The copolymer is obtained by a well-known method.

The hydrogenation reaction product of the phenolic resin is
Any known method, for example, dissolving the above phenolic resin in an organic solvent, in the presence of a homogeneous or heterogeneous catalyst,
It can be obtained by performing hydrogenation.

[0015] These alkali-soluble phenol resins can be used as those whose molecular weight and molecular weight distribution are controlled by known means. As a method for controlling the molecular weight or molecular weight distribution, the resin is crushed and solid-liquid extracted with an organic solvent having appropriate solubility, or the resin is dissolved in a good solvent and dropped into a poor solvent, or a poor solvent is used. Is added dropwise to perform solid-liquid or liquid-liquid extraction. These alkali-soluble phenol resins may be used alone or in combination of two or more. In the present invention, among these, an alkali-soluble phenol resin obtained by polycondensing a phenol and an aldehyde in the presence of an acid catalyst is particularly preferable.
Further, an alkali-soluble phenol resin (cresol novolak resin) using m-cresol and p-cresol as phenols is preferable. When a cresol novolak resin is used as the alkali-soluble resin, the content of m-cresol in the components is reduced to 60%.
It is desirable to do the following. The proportion of m-cresol is 60
%, The dissolution inhibiting power of the resin in an alkali developing solution is improved, and the residual film ratio is improved, so that a good pattern can be obtained.

(2) Quinonediazidesulfonic acid ester The quinonediazidesulfonic acid ester used in the present invention is used as a photosensitive agent. -Naphthoquinonediazide-5-sulfonic acid ester, 1,2-naphthoquinonediazide-4-sulfonic acid ester, 1,2-naphthoquinonediazide-6-sulfonic acid ester, 1,2-benzoquinonediazide-5-sulfonic acid ester1, 2-
Benzoquinonediazide-4-sulfonic acid esterified. Of these, 1,2-naphthoquinonediazide-5-sulfonic acid ester and 1,2-naphthoquinonediazide-4-sulfonic acid ester are preferable, and 1,2-naphthoquinonediazide-4-sulfonic acid ester is more preferable. 1,2-naphthoquinonediazide-4-
By using a sulfonic acid ester, a resist composition having a good balance between sensitivity and resolution can be provided. The polyphenols used herein have two or more, preferably three or more, and more preferably four phenolic hydroxyl groups in the molecule.

Specific examples include, but are not necessarily limited to, the following compounds. 2,3,4
-Trihydroxybenzophenone, 2,4,4'-trihydroxybenzophenone, 2,3,4,4'-tetrahydroxybenzophenone, 2,4,2 ', 4'-tetrahydroxybenzophenone, 2,3,4,2 ', 4'
Polyhydroxybenzophenones such as pentahydroxybenzophenone; tris (4-hydroxyphenyl)
Methane, 1,1,1-tris (4-hydroxy-3-methylphenyl) ethane, 1,1,1-tris (4-hydroxy-3-methylphenyl) ethane, 1,1,1-tris (4- Hydroxyphenyl) ethane, 1,1-bis (4-hydroxy-3-methylphenyl) -1- (4-
Hydroxyphenyl) ethane, bis (4-hydroxy-
Polyhydroxytrisphenylalkanes such as 3-methylphenyl) -2-hydroxy-4-methoxyphenylmethane; trimers of phenols and formalin; tetramers of phenols and formalin; and novolak resins. Among these, the phenolic hydroxyl group is a tetrahydroxybenzophenone,
Very preferred to give good sensitivity.

The method for producing these esters is not particularly limited, but quinonediazidesulfonic acid halide (preferably quinonediazidesulfonic acid chloride) is dissolved in a solvent such as acetone, dioxane, tetrahydrofuran or the like according to a conventional method in a solvent such as acetone, dioxane or tetrahydrofuran. Inorganic bases such as sodium oxide and potassium hydroxide, or
It can be obtained by reacting with a polyphenol compound in the presence of an organic base such as trimethylamine, triethylamine, tripropylamine, diisopropylamine, tributylamine, pyrrolidine, piperidine, piperazine, morpholine, pyridine and dicyclohexylamine.

In the ester used in the present invention, the ratio (average esterification ratio) of the quinonediazide sulfonic acid esterified hydroxyl group of the hydroxyl group of these polyphenols is equal to the equivalent number of hydroxyl groups of the polyphenols used in the reaction, and It is a value calculated from the number of moles of 2-naphthoquinonediazide-4-sulfonic acid halide, usually 75%
Or more, preferably 80% or more, more preferably 8% or more.
5% or more, and the upper limit is usually 100%, preferably 90%.
%. When the esterification ratio is 80 to 90%, the pattern shape and the resolution can be improved.

The photosensitizers used in the present invention may be used alone or in combination of two or more. For example, 1,2-naphthoquinonediazide-5-sulfonic acid ester is used in all photosensitizers. 20% by weight or less, preferably 10% by weight or less. The amount of the photosensitizer is usually 1 to 50 parts by weight, preferably 10 to 100 parts by weight of the alkali-soluble phenol resin.
-30 parts by weight. When the compounding amount is 10 to 30 parts by weight, it is possible to provide a resist composition having a good balance between the resist characteristics such as the effective sensitivity and the residual film ratio, the pattern shape, and the resolution.

(3) Aromatic ester compound In the present invention, a compound having an ester group-containing aromatic group represented by the above general formula (1) is added for the purpose of improving the contrast and resolution of the resist composition. I do.
The meaning of each symbol in the formula (1) is as described above, and preferred examples will be described below. R ′ and R ″ are preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, more preferably a hydrogen atom or an alkyl group. R is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may be branched. Groups are preferred, and more preferably a hydrogen atom or a group having 1 to 3 carbon atoms.
And particularly preferably a hydrogen atom or a methyl group. X is preferably a halogen atom, particularly preferably a chlorine atom or a bromine atom. p is preferably in the range of 0 <p ≦ 2, particularly preferably in the range of 0 <p ≦ 1. q is 0
The range of ≦ q ≦ 2 is preferable, and the range of 0 ≦ q ≦ 1 is particularly preferable. Here, p and q are the average number of moles of each group in the aromatic ester compound. The same applies to p1 to p4 and q1 to q4.

Preferred specific examples of the compound having an ester group-containing aromatic group represented by the formula (1) include a compound represented by the formula (2) or (3). The meanings of the symbols in each formula are as described above, and preferred examples correspond to the above formula (1).

The method for producing the compound having an ester group-containing aromatic group represented by the formula (1) is not particularly limited. For example, a compound having a phenolic hydroxyl group and R,
A method in which an organic acid having R ″ and X (hereinafter sometimes simply referred to as an organic acid) is dehydrated and condensed using a dehydrating agent such as carbodiimide, if necessary, in the presence of a suitable solvent; There is a method in which a halide of an organic acid is reacted with a phenolic compound having a phenolic hydroxyl group, etc. The amount of the organic acid to be used is from 0.8 to the molar equivalent of the phenolic hydroxyl group in the compound having the phenolic hydroxyl group. The molar amount is 1.5 times, preferably 1.0 to 1.3 times, based on the number of moles of the phenolic hydroxyl group of the compound having a phenolic hydroxyl group used in the reaction and the number of moles of the organic acid used in the reaction. The calculated value can be considered as the esterification rate.

Specific examples of the organic acid having R, R ″ and X include halogenated acetic acids such as fluoroacetic acid, chloroacetic acid and bromoacetic acid; halogenated acetic acids such as 2-chloropropionic acid and 2-bromopropionic acid Acids; 2-
Halogenated butanoic acids such as chloroisobutanoic acid, 2-chloro-n-butanoic acid, 2-bromoisobutanoic acid, 2-bromo-n-butanoic acid; 2-chloro-3-methylbutanoic acid;
2-bromo-3-methylbutanoic acid, 2-bromo-n-valeric acid, 2-chloro-3-methyl-n-valeric acid, 2-
Chloro-4-methyl-n-valeric acid, 2-bromo-n-
Examples include monovalent organic acids such as caproic acid and cyanoacetic acid,
Among them, chloroacetic acid, bromoacetic acid and the like are preferable because of their good reactivity.

Phenol compounds having a phenolic hydroxyl group include phenol, catechol, resorcinol,
Hydroquinone, phloroglucinol, pyrogallol,
o-cresol, m-cresol, p-cresol,
3-methylcatechol, 4-methylcatechol, 2-methylresorcin, 5-methylresorcin, 3-methoxyphenol, 4-methoxyphenol, 3-methoxycatechol, methoxyhydroquinone, 5-methylpyrogallol, 2-ethylphenol, 3- Ethylphenol, 4-ethylphenol, 2-ethoxyphenol,
3-ethoxyphenol, 4-ethoxyphenol, 4
-Ethylresorcinol, 2-arylphenol, 2-isopropylphenol, 3-isopropylphenol,
4-isopropylphenol, 2-n-propylphenol, 4-n-propylphenol, 4-n-propoxyphenol, 4- (2-methoxyethyl) phenol, 4-n-butylphenol, 2-sec-butylphenol, 4- sec-butylphenol, 2-tert-butylphenol, 3-tert-butylphenol, 4-tert
-Butylphenol, 3-butoxyphenol, 4-n
-Butoxyphenol, tert-butylhydroquinone,
4-tert-butyl pyrocatechol, 2-fluorophenol, 3-fluorophenol, 4-fluorophenol, 2-chlorophenol, 3-chlorophenol,
-Chlorophenol, 2-bromophenol, 3-bromophenol, 4-bromophenol, 2-iodophenol, 3-iodophenol, 4-iodophenol, 2-cyanophenol, 4-cyanophenol, 2
-Nitrophenol, 3-nitrophenol, 4-nitrophenol, 3-fluorocatechol, 3-chlorocatechol, 4-chlorocatechol, 4-chlororesorcin, chlorohydroquinone, 4-bromoresorcin, bromohydroquinone, 4-nitrocatechol, Monocyclic phenols such as 2-nitroresorcin;

2,3,4-trihydroxybenzophenone, 2,4,4'-trihydroxybenzophenone,
2,3,4,4′-tetrahydroxybenzophenone,
Polyhydroxybenzophenones such as 2,4,2 ', 4'-tetrahydroxybenzophenone and 2,3,4,2', 4'-pentahydroxybenzophenone; tris (4-hydroxyphenyl) methane, 1,1,1 -Tris (4-hydroxy-3-methylphenyl) ethane,
1,1,1-tris (4-hydroxy-3-methylphenyl) ethane, 1,1,1-tris (4-hydroxyphenyl) ethane, 1,1-bis (4-hydroxy-3-
Methylphenyl) -1- (4-hydroxyphenyl) ethane, bis (4-hydroxy-3-methylphenyl)-
Polyhydroxytrisphenylalkanes such as 2-hydroxy-4-methoxyphenylmethane;

Trimers or tetramers of phenols and formalin (phenols include phenol,
o-cresol, m-cresol, p-cresol,
2,3-xylenol, 2,4-xylenol, 2,6
-Xylenol, 3,5-xylenol, 1,2,3-
Trimethylphenol, 1,3,4-trimethylphenol, 1,3,5-trimethylphenol, 2,3,4
-Trimethylphenol, 2,4,5-trimethylphenol, 3,4,5-trimethylphenol, 3-methoxyphenol, 4-methoxyphenol, 2-ethylphenol, 3-ethylphenol, 4-ethylphenol, 2-ethoxy Phenol, 3-ethoxyphenol, 4-ethoxyphenol, 4-n-butylphenol, 2-sec-butylphenol, 4-sec-butylphenol, 2-tert-butylphenol, 3-tert-butylphenol, 4-tert-butylphenol, 3- Monovalent phenols such as butoxyphenol and 4-n-butoxyphenol are preferred. ); The following formulas (4a) to (4)
and phenols represented by the following formula (4):

[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]

Embedded image (In the formula (4), R ^{9 to} R ¹⁵ are the same as each symbol of the formula (3), and r 1 to r 4 are each greater than 0 and 4 or less.)

The amount of the aromatic ester compound to be added can be arbitrarily set depending on the composition, molecular weight, molecular weight distribution of the alkali-soluble phenolic resin and the type and amount of other additives. The upper limit is usually 30 parts by weight, preferably 20 parts by weight, more preferably 15 parts by weight, and the lower limit is usually 0.5 parts by weight, preferably 1 part by weight, more preferably 1 part by weight, based on 100 parts by weight of the soluble phenol resin. 2 parts by weight. When the amount of the aromatic ester compound added is 2 to 15 parts by weight, the effect of improving the contrast is the most effective, and there is no problem that the addition of the low-molecular compound deteriorates the adhesion to the substrate.

(4) Other additives (4-1) Phenol compound In the present invention, a phenol compound can be added for the purpose of improving sensitivity. The addition amount of these phenolic compounds depends on the composition of the alkali-soluble phenolic resin,
Although it varies depending on the molecular weight, molecular weight distribution, and the type and amount of other additives, the amount is usually an alkali-soluble phenol resin 1
The upper limit is usually 50 parts by weight, preferably 30 parts by weight, more preferably 20 parts by weight, and the lower limit is usually 1 part by weight, preferably 2 parts by weight, more preferably 3 parts by weight with respect to 00 parts by weight. .

The phenol compounds to be added include phenol, catechol, resorcin, hydroquinone,
Fluoroglucinol or a resin obtained by condensing a phenol disclosed in WO 96/22563 with an α, α'-2-substituted xylene in the presence of an acid catalyst, or a resin or a phenol and dicyclopentadiene as an acid catalyst Resin-based phenols such as resins obtained by condensation in the presence; monophenols such as p-phenylphenol, p-isopropylphenol; biphenol, 4,4 ′
-Dihydroxydiphenyl ether, 4,4'-dihydroxybenzophenone, bisphenol A (manufactured by Honshu Chemical Industry Co., Ltd.), bisphenol C (manufactured by Honshu Chemical Industry Co., Ltd.), bisphenol E (manufactured by Honshu Chemical Industry Co., Ltd.), bisphenol F (manufactured by Honshu Chemical Industry Co., Ltd.) ), Bisphenol AP (manufactured by Honshu Chemical), bisphenol M (manufactured by Mitsui Petrochemical), bisphenol P (manufactured by Mitsui Petrochemical), bisphenol Z (manufactured by Honshu Chemical), 1,1-bis ( 4-hydroxyphenyl) cyclopentane, 9,9-
Bis (4-hydroxyphenyl) fluorene, 1,1-
Bis (5-methyl-2-hydroxyphenyl) methane,
Bisphenols such as 3,5-dimethyl-4-hydroxybenzylphenol;

1,1,1-tris (4-hydroxyphenyl) methane, 1,1,1-tris (4-hydroxyphenyl) ethane, 1,1-bis (3-methyl-4-hydroxyphenyl) -1 Trishydroxyphenylmethanes such as-(4-hydroxyphenyl) methane and 1,1-bis (2,5-dimethyl-4-hydroxyphenyl) -1- (2-hydroxyphenyl) methane; 1,1-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,
Bishydroxyphenylmethylphenols such as 2,6-bis (3,5-dimethyl-4-hydroxybenzyl) -4-methylphenol;

Trisphenols such as trisphenol-PA (manufactured by Honshu Chemical Industry) and trisphenol-TC (manufactured by Honshu Chemical Industry); 1,1,2,2-tetrakis (4-hydroxyphenyl) ethane; , 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)-
4-xylene, α, α, α ′, α′-tetrakis (3-
Methyl-4-hydroxyphenyl) -3-xylene,
Bromoacetyl ester compounds such as tetrakisphenols such as α, α, α ′, α′-tetrakis (3-methyl-4-hydroxyphenyl) -4-xylene are exemplified.

(4-2) Other Additives Styrene, acrylic acid and methacrylic acid may be added to the positive resist composition of the present invention, if necessary, in order to improve developability, storage stability, heat resistance and the like. Copolymers of acid or maleic anhydride, copolymers of alkenes and maleic anhydride,
A vinyl alcohol polymer, vinyl pyrrolidone polymer, rosin, shellac and the like can be added. The addition amount of such a polymer is 0 to 50 parts by weight of the polymer based on 100 parts by weight of the total alkali-soluble phenolic resin,
Preferably it is 5 to 20 parts by weight. In addition, in the present invention, a surfactant, a storage stabilizer, a sensitizer, a striation inhibitor, a plasticizer, and other additives can be appropriately contained as necessary.

As the surfactant, for example, F-top
EF301, EF303, EF352 (manufactured by Shin-Akita Kasei), Megafax F171, F172, F17
3, F177 (Dai Nippon Ink Co., Ltd.), Florade FC4
30, FC431 (manufactured by Sumitomo 3M Limited), Asahigard AG710, Surflon S-382, SC-10
1, SC-102, SC-103, SC-104, SC
Fluorinated surfactants such as SC-105 and SC-106 (manufactured by Asahi Glass Co., Ltd.); organosiloxane polymer KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.); acrylic acid or methacrylic acid (co) polymer Polyflow No. 75, no. 95 (manufactured by Kyoeisha Yushi Kagaku Kogyo KK) and the like. The amount of these surfactants per 100 parts by weight of the solid content of the composition,
Usually, it is at most 2 parts by weight, preferably at most 1 part by weight.

(5) Solvent The positive resist composition of the present invention is usually used by dissolving it in a solvent in order to form a resist film by coating it on a substrate.
Specific examples of the solvent used in the present invention include acetone, methyl ethyl ketone, cyclopentanone 2-hexanone,
-Hexanone, 2-heptanone, 3-heptanone, 4-
Linear ketones such as heptanone, 2-octanone, 3-octanone, and 4-octanone; alcohols such as n-propyl alcohol, iso-propyl alcohol, n-butyl alcohol and cyclohexanol; ethylene glycol dimethyl ether, ethylene glycol diethyl Ethers such as 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, ethyl propionate, methyl butyrate, ethyl butyrate; Esters such as methyl lactate and ethyl lactate;

Cellosolve esters such as cellosolve acetate, methyl cellosolve acetate, ethyl cellosolve acetate, propyl cellosolve acetate and butyl cellosolve acetate; propylene glycol, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol Propylene glycols such as monobutyl ether; diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycols such as diethylene glycol methyl ethyl ether; γ-butyrolactone;
saturated γ-lactones such as γ-valerolactone, γ-caprolactone, γ-caprylolactone; halogenated hydrocarbons such as trichloroethylene; aromatic hydrocarbons such as toluene and xylene; dimethylacetamide, dimethylformamide, N- Polar solvents such as methylacetamide; and the like. These solvents may be used alone or
A combination of more than one species may be used. The amount of the solvent used is an amount sufficient to uniformly dissolve the components.

(6) Method of Use (6-1) Preparation of Resist The positive-working resist of the present invention containing the alkali-soluble resin, quinonediazidesulfonic acid ester, organic acid polycyclic aromatic ester compound and, if necessary, various additives. The resist composition is dissolved in a solvent, and this solution is applied on a substrate and dried to form a resist film. As a coating method at this time, spin coating is particularly recommended. (6-2) Exposure Exposure sources used for exposure for forming a pattern on the resist film thus obtained include ultraviolet light, far ultraviolet light, KrF excimer laser light, X-rays, and electron beams. Particularly preferred is exposure with an electron beam. Furthermore, when heat treatment (post-exposure bake) is performed after exposure,
This is preferable because sensitivity, residual film ratio, resolution, and heat resistance can be improved.

(6-3) Development Usually, an alkaline aqueous solution is used as a developer for the composition of the present invention. Specific examples include aqueous solutions of inorganic alkalis such as sodium hydroxide, lithium hydroxide, potassium hydroxide, sodium silicate, and ammonia; ethylamine;
Aqueous solutions of primary amines such as propylamine; aqueous solutions of secondary amines such as diethylamine and dipropylamine;
Aqueous solutions of tertiary amines such as trimethylamine and triethylamine; methylaminoethanol, ethylaminoethanol, dimethylaminoethanol, diethylaminoethanol, dibutylaminoethanol, N-methyldiethanolamine, N-ethyldiethanolamine, triethanolamine, N-methylanilinoethanol , N
Aqueous solutions of amino alcohols such as -ethylanilinoethanol; quaternary such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, N-phenyltrimethylammonium hydroxide and N-phenyltriethylammonium hydroxide An aqueous solution of ammonium hydroxide is exemplified. These alkaline aqueous solutions can be used alone or in combination. In order to prevent the occurrence of defects during development, pH buffering agents such as carbonate and tetraborate, surfactants, and water-soluble organic solvents such as methanol, ethanol, propanol, and ethylene glycol are added thereto. Can be used.

[0046]

The present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples. Parts in the text are based on weight unless otherwise specified.

[Synthesis Example 1] Synthesis of Novolak Resin A-1 A 2 liter flask equipped with a cooling pipe and a stirrer was put into a flask.
310 parts of m-cresol, 466 parts of p-cresol, 3
394 parts of 6% formalin and 2.45 of oxalic acid dihydrate
The reaction was carried out for 35 minutes while maintaining the temperature at 95 to 100 ° C. Thereafter, water was distilled off at 100 to 105 ° C. over 100 minutes, and the temperature was raised to 170 ° C. for 10 m.
The pressure was reduced to mHg, and the temperature was further raised to 190 ° C. to remove unreacted monomers and residual water. Thereafter, the molten resin was returned to room temperature to obtain 544 parts of novolak resin A-1. The weight average molecular weight (Mw) of this novolak resin measured in terms of polystyrene by gel permeation chromatography using tetrahydrofuran was 3,300.

Synthesis Example 2 Synthesis of Novolak Resin A-2 Novolak resin A-2 was prepared in the same manner as in Synthesis Example 1 except that 466 parts of m-cresol and 310 parts of p-cresol were used.
-2 650 parts were obtained. The weight average molecular weight (Mw) of this novolak resin measured by the same method as in Synthesis Example 1 was 560.
It was 0.

[Synthesis Example 3] Synthesis of Novolak Resin A-3 A 2 liter flask equipped with a cooling pipe and a stirrer was put into a flask.
318 parts of m-cresol, 238 parts of p-cresol,
89 parts of 2,3,4-trimethylphenol, 125 parts of paraformaldehyde and 2.5 parts of oxalic acid dihydrate were added, and the mixture was reacted at 95 to 100 ° C. for 35 minutes. Thereafter, water was distilled off at 100 to 105 ° C. over 2 hours, and the pressure was reduced to 10 mmHg while the temperature was increased to 180 ° C., and the temperature was further increased to 190 ° C. to remove unreacted monomers and residual water. . Thereafter, the molten resin was returned to room temperature to obtain 335 parts of novolak resin A-3. The weight average molecular weight (Mw) of this novolak resin measured in terms of polystyrene by gel permeation chromatography using tetrahydrofuran was 3,000.

[Synthesis Example 4] Synthesis of quinonediazidesulfonic acid ester B-1 2,3,4,4'-tetrahydroxybenzophenone was used as a polyphenol compound.
An amount of 1,2-naphthoquinonediazide-4-sulfonic acid chloride corresponding to 5 mol% was dissolved in dioxane to give 1
A 0% solution was obtained. While controlling the temperature at 20 to 25 ° C., 1.2 equivalents of triethylamine of 1,2-naphthoquinonediazide-4-sulfonic acid chloride was added dropwise over 30 minutes, and the reaction temperature was maintained for 2 hours. Was completed. The precipitated salt was separated by filtration and poured into a 0.2% aqueous oxalic acid solution 10 times as much as the reaction solution. The precipitated solid was filtered, washed with ion-exchanged water, and dried to obtain quinonediazidesulfonic acid ester B-1.

[Synthesis Example 5] Synthesis of quinonediazidesulfonic acid ester B-2 The polyphenol compound was changed to tris (4-hydroxyphenyl) methane, and 1,2-naphthoquinonediazide-4-sulfonic acid chloride was replaced with this hydroxyl group 90. 0
A quinonediazidesulfonic acid ester B-2 was obtained in the same manner as in Synthesis Example 4 except that the amount was equivalent to mol%.

[Synthesis Example 6] Synthesis of quinonediazidesulfonic acid ester B-3 2- (4- (1,1-bis (4-hydroxyphenyl) ethyl) phenyl) -2 as a polyphenol compound
-(4-hydroxyphenylpropane), 1,
Quinonediazidesulfonic acid ester B-3 was obtained in the same manner as in Synthesis Example 4 except that the amount of 2-naphthoquinonediazide-4-sulfonic acid chloride was changed to an amount corresponding to 90.0 mol% of the hydroxyl groups.

[Synthesis Example 7] Aromatic ester compound C-1
Synthesis of 3.00 g of hydroquinone and 8.33 g of bromoacetic acid were dissolved in tetrahydrofuran to give a 10% solution. 0-5
While controlling the temperature at 0 ° C., 123.7 g of a 10% solution of dicyclohexylcarbodiimide in tetrahydrofuran was added to 3
The mixture was added dropwise over 0 minutes, and the reaction temperature was set to room temperature, and the reaction was maintained for 2 hours to complete the reaction. The precipitated by-product was separated by filtration, and the reaction solution was evaporated to dryness to obtain a product. This product was dissolved in methanol at 60 ° C., and the insoluble material was filtered off.
Recrystallized at ° C. After filtration, the obtained plate-like crystals were dried in vacuo, and the carboxylic acid aromatic ester compound C-1 6.0 was used.
0 g was obtained.

[Synthesis Example 8] Aromatic ester compound C-2
Synthesis of Phloroglucinol 3.00 Instead of Hydroquinone
g, 10.91 g of bromoacetic acid, 162.1 g of a 10% solution of dicyclohexylcarbodiimide in tetrahydrofuran
Except having changed to, the carboxylic acid aromatic ester compound C-2 was obtained in the same manner as in Synthesis Example 7.

Synthesis Example 9 Aromatic ester compound C-3
Synthesis of chloroacetic acid instead of bromoacetic acid, 2.00 g, hydroquinone, 3.00 g, dicyclohexylcarbodiimide 1
A carboxylic acid aromatic ester compound C-3 was obtained in the same manner as in Synthesis Example 7, except that the 0% tetrahydrofuran solution was changed to 61.5 g.

[Synthesis Example 10] Aromatic ester compound C-
Synthesis of 4 4.10 g of the above formula (3a) and 4.59 g of bromoacetic acid were dissolved in tetrahydrofuran to prepare a 10% solution. 0 to
While controlling the temperature at 5 ° C., 68.1 g of a 10% solution of dicyclohexylcarbodiimide in tetrahydrofuran was added to 3
The mixture was added dropwise over 0 minutes, and the reaction temperature was set to room temperature, and the reaction was maintained for 2 hours to complete the reaction. Subsequent processing is described as Synthesis Example 7.
Was performed in the same manner as described above, and 3.48 of the aromatic ester compound C-4.
g was obtained.

[Synthesis Example 11] Aromatic ester compound C-
Synthesis of 5 A carboxylic acid aromatic ester compound C-2 was obtained in the same manner as in Synthesis Example 10 except that 4.24 g of the formula (3g) was used instead of the formula (3a).

[Synthesis Example 12] Aromatic ester compound C-
Synthesis of 6 An aromatic ester compound C-6 was obtained in the same manner as in Synthesis Example 11, except that chloroacetic acid was changed to 3.12 g instead of bromoacetic acid.

Synthesis Example 12 Synthesis of Carboxylic Aromatic Ester Compound C-7 Aromatic ester was prepared in the same manner as in Synthesis Example 10 except that 4.66 g of formula (3i) was used instead of formula (3a). Compound C-7 was obtained.

[Synthesis Example 13] Aromatic ester compound C-
Synthesis of 8 4.72 g of the formula (3k) and 9.17 g of bromoacetic acid were dissolved in tetrahydrofuran to prepare a 10% solution. 0-5 ° C
While controlling the temperature, 136.2 g of a 10% solution of dicyclohexylcarbodiimide in tetrahydrofuran was added to 45 ml.
The mixture was added dropwise over a period of minutes, and the reaction temperature was set to room temperature, and the reaction was maintained for 2 hours to complete the reaction. The subsequent treatment was performed in the same manner as in Synthesis Example 7 to obtain 3.60 g of an aromatic ester compound C-8.

Synthesis Example 14 Synthesis of Ester Compound C-9 An ester compound C-9 was obtained in the same manner as in Synthesis Example 7, except that 3.6 g of acetic acid was used instead of bromoacetic acid. This compound does not contain a halogen atom.

Examples 1 to 13 and Comparative Examples 1 to 3 Novolak resins obtained in Synthesis Examples 1 to 3 and quinonediazide sulfonic acid esters obtained in Synthesis Examples 4 to 6 Synthesis Examples 7 to
As an organic acid polycyclic aromatic ester compound obtained in Step No. 14 and a phenol compound, "Trisphenol PA" (product name: 2- (4- (1,1-bis (4
-Hydroxyphenyl) ethyl) phenyl) -2- (4
-Hydroxyphenyl) propane) was dissolved in 2-heptanone in parts by weight as shown in Table 1, and the pore size was 0.1 μm.
Was filtered through a polytetrafluoroethylene (PTFE) membrane filter to prepare a resist solution.

This resist solution was spin-coated on a silicon wafer coated with chromium oxide having a thickness of 800 angstroms, and baked on a hot plate at 100 ° C. for 90 seconds to form a resist film having a thickness of 5000 angstroms. Next, the resist film formed on the silicon wafer was coated with an electron beam lithography apparatus ELS-3300 (manufactured by Elionix, Inc., pencil beam type) at an acceleration voltage of 20 kV and an irradiation current of 1 × 10 ⁻¹¹ ° to 0.3 μm.
Pattern drawing of five sets of lines and spaces was performed sequentially from m to 1.0 μm in increments of 0.1 μm by changing the drawing time. After pattern drawing, development was carried out by immersing in a 1.0% aqueous potassium hydroxide solution at 23 ° C. for 60 seconds, followed by rinsing with pure water to obtain a positive pattern. After pattern formation, the execution sensitivity, residual film ratio, pattern shape, and resolution were confirmed by an electron microscope. Tables 1 and 3 show the composition of each resist, and Tables 2 and 4 show the evaluation results.

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[Table 1]

[0065]

[Table 2]

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[Table 3]

[0067]

[Table 4]

The criteria for each evaluation are as follows. <Execution sensitivity> The drawing energy amount when the line & space of 1.0 μm becomes 1: 1 is described. Note that an energy amount of 8 to 12 μC / sqcm is a value that is practically no problem. <Residual film ratio> The ratio (%) of the resist film thickness before and after development of a portion where a pattern is not formed on the wafer is shown.

<Pattern Shape> The wafer on which the resist pattern is formed is cut in a direction perpendicular to the line pattern.
The results of observation with an electron microscope from the cross-sectional direction of the pattern are shown. The case where the angle at which the pattern sidewall rises with respect to the substrate was 80 degrees or more was judged to be best, and the case where the angle was 70 to 80 degrees or more was judged to be good. Those with less than 70 degrees are described as "taper" in the table. <Resolution> The minimum dimension to be resolved by the amount of energy when the line & space of 1 μm becomes 1: 1 under the above-mentioned drawing conditions is described.

[0070]

EFFECTS OF THE INVENTION The resist composition of the present invention is not only excellent in resist characteristics such as resolution and contrast but also gives a good pattern shape without uneven development, particularly in an electron beam lithography system. This is particularly suitable for manufacturing a photomask manufactured using an electron beam.

Claims (2)

[Claims] 1. A positive resist composition comprising an alkali-soluble resin, a quinonediazidesulfonic acid ester compound, and an aromatic ester compound having an ester group-containing aromatic group represented by the following general formula (1). Embedded image (In the formula (1), R ′ and R ″ are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and R is independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may be branched. X is a halogen atom, a nitro group or a cyano group, or an alkoxy group, an alkenyl group, an aryl group or an aryloxy group having 2 to 7 carbon atoms which may be branched, and 0 <p, 0 ≦ q. 0 <(p + q) ≦ 4
It is. ) 2. The positive resist composition according to claim 1, wherein the aromatic ester compound is a compound represented by the following general formula (2) or (3). Embedded image (In the formula (2), R ¹ and R ² are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and R ¹² is a hydrogen atom and an alkyl group having 1 to 6 carbon atoms which may be branched. Or an alkoxy group, an alkenyl group having 2 to 7 carbon atoms which may be branched, an aryl group, or an aryloxy group, and X ¹ is a halogen atom, a nitro group, or a cyano group, and 0 <p1, 0 ≦ q1. And 0 <(p1 + q
1) ≦ 4. ) (In the formula ^{(3), R} 1 ~R ¹¹ independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon ^{atoms,, R 12} ~
R ¹⁵ is each independently a hydrogen atom, an alkyl or alkoxy group having 1 to 6 carbon atoms which may be branched,
7-branched alkenyl group which may, an aryl group or an aryloxy group,, X ¹ to X ⁴ is a halogen atom, a nitro group or a cyano group. Furthermore, 0 <p1,
p2, p3, p4, and 0 ≦ q1, q2, q3, q4
And (p1 + q1), (p2 + q2), (p3 + q
3) and (p4 + q4) are each independently 0 to 4, and at least one of them is more than 0 and 4 or less. )