JPH06273928A - Positive photoresist composition - Google Patents

Abstract

PURPOSE:To provide a solvent improving the storage stability and the coating performance of the positive resist composition at the same time. CONSTITUTION:The photoresist composition contains an alkalisoluble resin and a 1,2-quinonediazido compound and a solvent having a boiling point of 120-180 deg.C represented by general formula I in which n is an integer of 1-4; each of R1 and R2 is H, methyl, or ethyl but both are not methyl or ethyl at the same time; and each of R3 and R4 is H or 1-6C alkyl, aryl, or benzyl. Therefore, the positive photoresist composition superior in stability against time lapse, causing no precipitate or no deposit of fine particles even during storage for a long period, good in coating performance, and free from any striation and capable of forming an extremely smooth resist film can be obtained by dissolving the alkali-soluble resin 1,2-quinonediazido composition in the specified solvent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation-sensitive positive photoresist, and more specifically to an IC.
The present invention relates to a photoresist composition having excellent coating performance, solution stability, and fine workability used in semiconductor manufacturing processes such as the above, and processes such as circuit manufacturing of liquid crystal thermal heads and the like.

[0002]

2. Description of the Related Art As a positive photoresist composition,
Generally, a composition is known in which an alkali-soluble resin and a 1,2-quinonediazide compound as a radiation-sensitive compound are dissolved in a solvent. By using a positive resist composition in which a radiation-sensitive compound is blended with these alkali-soluble resins, the radiation-irradiated portion is dissolved in a developing solution containing an alkaline aqueous solution, and a high resist pattern can be obtained that is faithful to the mask. In particular, in recent years when a high degree of integration of integrated circuits is required, a positive resist composition using an alkali-soluble resin having an excellent resolution is widely used.

However, in the positive photosensitive resin composition, for example, 2-ethoxyethyl acetate as a solvent,
A novolac resin such as cresol is used as an aqueous solution of an alkaline aqueous solution, and a naphthoquinonediazide-based photosensitizer is used as a 1,2-quinonediazide compound. When the resin composition is filtered through a 0.2 μm filter and left to stand, it is produced with the passage of time. Fine particles that cannot be observed with the naked eye are sometimes generated, and when the particles are stored for a long period of time, the precipitation may be observed. When a resist composition containing such fine particles is used to form a resist pattern on a substrate, fine particles remain in the portion where the resist is removed by development, and there is a problem that the resolution is reduced.

As a method for suppressing the formation of fine particles in the resist composition, a method of acylating a part of the hydroxyl groups of the polyhydroxy compound used for the synthesis of the 1,2-quinonediazide compound (Japanese Patent Laid-Open No. 62-178562). ), A method using a monooxymonocarboxylic acid ester as a solvent (JP-A-62-123444), a method using amide-form solvent dimethylformamide (JP-A-62-280844), and a cyclopentanone. Method
(JP-A-59-155838) has been proposed.

Further, in addition to the above problems, when the composition is applied to a substrate, application unevenness called striation occurs, the linearity and reproducibility of the pattern deteriorate, and desired accuracy is obtained. There is a problem that there is no. A method of adding a fluorine-containing surfactant to a solvent for a known resist composition for the purpose of improving the coating property (Japanese Patent Laid-Open No. 36657/1987).
JP-A-58-203434), a method of combining cyclopentanone and an aliphatic alcohol having 5 to 12 carbon atoms (JP-A-59-231534), and 60
A method of combining a solvent having a boiling point of 170 to 170 ° C. and a solvent having a boiling point of 180 to 350 ° C. (JP-A-60-2)
No. 4545) has been proposed.

[0006]

It is known that the storage stability and coating performance of the positive resist composition as described above are greatly influenced by the characteristics of the solvent used. At present, there is almost no known solvent that simultaneously improves these two problems of coating performance. The object of the present invention is, firstly, that the storage stability of the solution is excellent,
It is an object of the present invention to propose a positive photoresist composition which does not cause precipitation of fine particles of a photosensitizer during storage. Furthermore,
The second object is to provide a positive photoresist composition having excellent coating performance without striation and the like.

[0007]

Means for Solving the Problems As a result of intensive studies by the present inventors in order to solve the above-mentioned problems, the use of a cyclic diether solvent of a certain kind resulted in a specific improvement in storage stability and coating performance. The present invention has been achieved and has reached the present invention.
That is, the present invention provides a positive photoresist composition containing an alkali-soluble resin, a 1,2-quinonediazide compound and a solvent, which is represented by the general formula (1) and has a boiling point of 120 to
The present invention relates to a positive resist composition, which comprises using a solvent containing a cyclic diether compound at 180 ° C.

[Chemical 2]

The present invention will be described in detail below. General formula
Examples of the solvent represented by (I) and having a boiling point of 120 to 180 ° C. are 2,2-n-propyl-1,3-dioxolane, 2,2-n-butyl-1,3-dioxolane, 2-benzyl-1,3-dioxolane, 2,2-Di-n-propyl-4-methyl-1,3-dioxolane, 2,2-diisopropyl-4-methyl-1,3-dioxolane, 2,2-di-n-butyl-4-methyl-1,3dioxolane, 2
-N-butyl-4-methyl-1,3-dioxolane, 2
-N-propyl-4-methyl-1,3-dioxolane,
2-benzyl-4-methyl-1,3-dioxolane, 2
-Methyl-2-isobutyl-4-methyl-1,3-dioxolane, 2-methyl-2-isobutyl-4-ethyl-1,3-dioxolane, 2-n-butyl-4-ethyl-1,
3-dioxolane, 2-n-propyl-4-methyl-1,
3-dioxane, 2-n-butyl-4-methyl-1,3-dioxane, 2-n-propyl-1,3-dioxepane and the like.

The preferred boiling range is 120 to 180 ° C.,
More preferably, it is 130 to 170 ° C. As a solvent for photoresist, a solvent with a flash point as high as possible is desired in order to prevent the risk of fire, etc., but a solvent with a higher flash point requires higher temperature and longer time to completely evaporate in the baking process. . However, the 1,2-quinonediazide compound used as a radiation-sensitive agent has a relatively low decomposition temperature, so the baking temperature cannot be so high. Therefore, the use of a solvent having a high boiling point is practically limited. On the other hand, when a highly volatile solvent is used, the spin-coating method on the substrate makes the evaporation time too fast as compared with the spreading time of the resist, making it difficult to uniformly apply the photoresist.

The above-mentioned solvent is generally a glycol such as ethylene glycol or propylene glycol and a ketone or aldehyde such as methyl isobutyl ketone, methyl ethyl ketone, di-n-propyl ketone, n-propyl aldehyde, n-butyraldehyde or sulfuric acid, p-
It can be produced by reacting under an acidic catalyst such as toluenesulfonic acid or heteropolyacid. In the present invention, it is preferable to mainly use the compound represented by the general formula (1), but other solvents can be mixed and used within the range of less than 50 wt%, preferably less than 30 wt% of the total amount of the solvent.

Specific examples of the solvent which can be mixed include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether,
Propylene glycol monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, benzyl ethyl ether, dihexyl ether and other ethers, methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol monomethyl ether acetate, acetic acid Ethyl, butyl acetate, benzyl acetate, ethyl benzoate, diethyl oxalate, diethyl maleate, ethylene carbonate, propylene carbonate, γ-butyrolactone, and other esters, methyl ethyl ketone, cyclohexanone, diisobutyl ketone, acetonylacetone, isophorone, and other ketones , Fatty acids such as caproic acid and caprylic acid, 1-octanol,
Examples thereof include alcohols such as 1-nonanol and benzyl alcohol, and aromatic hydrocarbons such as toluene and xylene.

Examples of the alkali-soluble resin used in the present invention include novolac resin, acetone-pyrogallol resin, polyhydroxystyrene and derivatives thereof. Among these, novolac resin is particularly preferable,
It is obtained by addition-condensing phenols and aldehydes in the presence of an acidic catalyst.

Examples of the phenols used at this time include phenol, o-cresol, m-cresol, p-cresol, o-ethylphenol, m-ethylphenol, p-ethylphenol, o-butylphenol, m-butylphenol and p. -Butylphenol, 2,3-xylenol, 2,4-xylenol, 2,
5-xylenol, 2,3-xylenol, 3,4-xylenol, 3,5-xylenol, 2,3,5-trimethylphenol, p-phenylphenol, hydroquinone, catechol, resorcinol, 2-methylresorcinol, pyrogallol, α-naphthol, bisphenol A , Dihydroxybenzoic acid ester, gallic acid ester, and the like can be used alone or in combination of two or more, but are not limited thereto.

Examples of aldehydes include formaldehyde, paraformaldehyde, acetaldehyde, propylaldehyde, benzaldehyde, phenylacetaldehyde, α-phenylpropylaldehyde,
β-phenylpropyl aldehyde, o-hydroxybenzaldehyde, m-hydroxybenzaldehyde, p-hydroxybenzaldehyde, o-chlorobenzaldehyde, m-chlorobenzaldehyde, p-chlorobenzaldehyde, o-nitrobenzaldehyde, m-nitrobenzaldehyde, p-nitrobenzaldehyde , O-methylbenzaldehyde, m-methylbenzaldehyde, p-methylbenzaldehyde, p-ethylbenzaldehyde, pn-butylbenzaldehyde and the like, among which, formaldehyde, acetaldehyde and benzaldehyde are preferable. These aldehydes can be used alone or in combination of two or more.

Aldehydes are used per mol of phenols,
Usually, it is used in a proportion of 0.7 to 3 mol, preferably 0.7 to 2 mol. As the acid catalyst, inorganic acids such as sulfuric acid, hydrochloric acid, acetic acid and formic acid, and organic acids can be used. The weight average molecular weight of the novolak resin thus obtained is 2000 to 30000.
The range is preferably. If it is less than 2,000, the film loss of the unexposed area after development is large, and if it exceeds 30,000, the developing speed becomes small. 600 is particularly suitable
It is in the range of 0 to 20000.

The 1,2-quinonediazide compound used in the present invention is 1,2-benzoquinonediazide 4
-Sulfonic acid ester, 1,2 naphthoquinone diazide 4-sulfonic acid ester, 1,2 naphthoquinone diazide 5-sulfonic acid ester and the like. These compounds are already known compounds and include a polyhydroxy compound, 1,2-benzoquinone diazide 4-sulfonyl chloride, 1,2-naphthoquinone diazide 4-sulfonyl chloride and 1,2 naphthoquinone diazide 5- Obtained by reacting with sulfonyl chloride and the like.

As the polyhydroxy compound, one having three or more hydroxyl groups in one molecule is preferable, and trihydroxyphenylalkylketone such as trihydroxyphenylmethylketone, trihydroxybenzophenone,
Examples thereof include gallic acid esters such as tetrahydroxybenzophenone, methyl gallate, and propyl gallate.

The reaction can be synthesized by dissolving in a solvent such as dioxane, tetrahydroquinone, acetone, methyl ethyl ketone, water, cellosolve, etc., and carrying out a dehydrochlorination reaction using a basic catalyst to accelerate the reaction. As the basic catalyst, inorganic bases such as sodium carbonate, potassium carbonate, sodium hydroxide and potassium hydroxide, and organic bases such as triethylamine, triethanolamine and diethylamine are usually used. The synthesis temperature is not particularly limited, but it is 0 to 4 from the viewpoint of stability of main product and reaction rate.
The range of 0 ° C is preferred.

The reaction ratio between the polyhydroxy compound and the above-mentioned 1,2-quinonediazido-4-sulfonyl chloride is 1 mol to 1 mol of the mono- or polyhydroxy compound and the same mol number as the number of hydroxyl groups of the polyhydroxy compound. Only a few 1,2-quinonediazide compounds are commonly used.

The 1,2-quinonediazide compound obtained as described above is used alone or in the resist composition.
Alkali-alkali-soluble resin is distributed by mixing more than one species. The blending amount thereof is 5 to 100 parts by weight, preferably 10 to 5 parts by weight, based on 100 parts by weight of the alkali-soluble resin.
0 parts by weight. If it is less than 5 parts by weight, patterning is difficult because the amount of carboxylic acid produced by the 1,2-quinonediazide compound absorbing radiation is small, and if it exceeds 100 parts by weight, sensitivity and solubility in a solvent decrease.

The positive photoresist composition of the present invention may contain a surfactant in order to further improve coating properties such as striation. Examples of the surfactant include polyoxyethylene lauryl ether,
Polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, polyoxyethylene oleyl ether and other polyoxyethylene alkyl ethers, polyoxyethylene octylphenol ether, polyoxyethylene nonylphenol ether and other polyoxyethylene alkyl allyl ethers, polyoxyethylene・ Polyoxypropylene block copolymers, sorbitan monolaurate, sorbitan monopalmitate,
Sorbitan fatty acid esters such as sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, sorbitan tristearate, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, poly Nonionic surfactants such as polyoxyethylene sorbitan fatty acid esters such as oxyethylene sorbitan trioleate and polyoxyethylene sorbitan tristearate, F-top EF
301, EF303, EF352 (manufactured by Shin-Akita Kasei Co., Ltd.),
MegaFac F171, F173 (Dainippon Ink Co., Ltd.)
), Fluorard FC-430, FC-431 (Sumitomo 3M Limited), Asahi Guard AG710, Surflon S-382, SC101, SC102, SC103, S
Fluorine-based surfactants such as C104, SC105, SC106 (manufactured by Asahi Glass Co., Ltd.), organosiloxane polymer KP
341 (manufactured by Shin-Etsu Chemical Co., Ltd.) or acrylic acid-based or methacrylic acid-based (co) polymerization polyflow No. 75, No. 95
(Kyoeisha Yushi Kagaku Kogyo Co., Ltd.) and the like can be mentioned.
The content 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 alkali-soluble resin and the quinonediazide compound in the composition of the present invention. These surfactants may be added alone or as a mixture of some.

The developer for the positive photoresist composition of the present invention includes, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, inorganic alkalis such as aqueous ammonia, ethylamine, n-propylamine and the like. Primary amines, secondary amines such as diethylamine and di-n-propylamine, tertiary amines such as triethylamine and methyldiethylamine, alcohol amines such as dimethylethanolamine and triethanolamine, tetramethylammonium hydroxide, An alkaline aqueous solution prepared by dissolving a quaternary ammonium salt such as tetraethylammonium hydroxide or a cyclic amine such as pyrrole or piperidine is used. It is preferable to use an aqueous solution of a quaternary ammonium salt or a cyclic amine when producing an integrated circuit in which the use of a developer containing a metal poses a problem.

An aqueous solution prepared by adding an appropriate amount of a water-soluble organic solvent, for example, alcohols such as methanol and ethanol or a surfactant to the developing solution can be used as the developing solution. The above-mentioned positive photoresist composition is used to form a substrate (eg, silicon / silicon) used for manufacturing precision integrated circuit devices.
After coating with a suitable coating method of spinner and coater on (silicon dioxide coating), it is exposed through a predetermined mask,
A good resist can be obtained by developing.

[0024]

INDUSTRIAL APPLICABILITY According to the present invention, the alkali-soluble resin and the 1,2-quinonediazide compound are dissolved in a specific solvent to have excellent stability over time, and no precipitation or precipitation of fine particles occurs even after long-term storage. Further, a positive photoresist composition having good coatability and free from striation and forming a very smooth resist film can be obtained.

[0025]

EXAMPLES The present invention will be described below with reference to examples.
The present invention is not limited to these.

Example 1 m-cresol / p-cresol = 6/4
100 parts by weight of novolak resin obtained by addition condensation of (by weight) mixed cresol and formaldehyde and 2, 3, 4
-Trihydroxybenzophenone and 1,2-naphthoquinone- (2) -diamide-5-sulfonyl chloride ester 25 parts by weight, fluorine-based surfactant "S-382"
(Asahi Glass Co., Ltd.) 0.05 part by weight of 2-methyl-2-isobutyl-4-methyl-1,3 dioxolane (boiling point 140
(° C) 350 parts by weight, and filtered using a 0.2 μm microfilter to prepare a positive photoresist composition.

This photoresist composition was coated on a silicon wafer with a spinner coater and placed in an oven 9
Baking was carried out at 0 ° C. for 25 minutes to obtain a resist film. The surface of the resist film was observed by an optical microscope to examine the formation of gel-like material and the occurrence of striation, but none was observed. Furthermore, the prepared photoresist composition was added to 4
A time-course test for generation of fine particles was performed while keeping the temperature at 0 ° C. To confirm the deposit, the photoresist composition was applied onto a silicon wafer with a spinner coater in the same manner as above, and the deposit on the wafer was observed with an optical microscope. As a result of this aging test, no gel-like substance was confirmed even after 2400 hours passed after filtration, and it was confirmed that the composition was quite stable.

[0027]

Example 2 Instead of 2-methyl-2-isobutyl-4-methyl-1,3dioxolane of Example 1, 2,2-di-n was used.
Propyl-4-methyl-1,3-dioxolane (boiling point 170
A photoresist composition was prepared in the same manner as in Example 1 except that (.degree. C.) was used. This composition was evaluated in the same manner as in Example 1. When the coatability was examined, no striation was observed, and no precipitate was observed after 2400 hours in the aging test.

[0028]

Example 3 Instead of 2-methyl-2-isobutyl-4-methyl-1,3dioxolane of Example 1, 2,2-di-n-propyl-4-methyl-1,3dioxolane (boiling point 14
A photoresist composition was prepared and evaluated in the same manner as in Example 1 except that 0 ° C.) was used. No striation was observed in this composition, and no precipitate was observed even after 2000 hours.

[0029]

Example 4 Example 1 was repeated using 2-n-propyl-4-methyl-1,3 dioxane instead of 2-methyl-2-isobutyl-4-methyl-1,3 dioxolane of Example 1.
A photoresist composition was prepared and evaluated in the same manner as in. No striation was observed in this composition, and no precipitate was observed even after 2000 hours.

[0030]

Example 6 100 parts by weight of the novolak resin used in Example 1, 25 parts by weight of an ester of 2,3,4,4'-tetrahydroxybenzophenone and 1,2 naphthoquinone- (2) -diamide-5-sulfonyl chloride, and fluorine 0.05 parts by weight of a surfactant "S-382" (manufactured by Asahi Glass Co., Ltd.) was added to 2-methyl-2-isobutyl-4-methyl-1,3.
It was dissolved in 350 parts by weight of dioxolane and filtered through a 0.2 μm microfilter to prepare a photoresist composition, which was evaluated in the same manner as in Example 1. In terms of coatability, no striation was observed, and no precipitate was observed after 2400 hours.

[0031]

Comparative Example 1 A photoresist composition was prepared in the same manner as in Example 1 except that ethylene glycol monoethyl ether acetate was used instead of 2-methyl-2-isobutyl-4-methyl-1,3dioxolane of Example 1. When this composition was evaluated in the same manner as in Example 1, pinholes were not observed in the coatability, but striation was observed, and precipitates were confirmed after 700 hours had elapsed.

[0032]

Comparative Example 2 A photoresist composition was prepared in the same manner as in Example 6 except that ethyl lactate was used instead of 2-methyl-2-isobutyl-4-methyl-1,3dioxolane of Example 6. When this composition was evaluated in the same manner as in Example 1, striation was observed in the coatability,
Precipitates were observed after 900 hours.

Claims (2)

[Claims] 1. A positive photoresist composition containing an alkali-soluble resin, a 1,2-quinonediazide compound and a solvent, which is represented by the general formula (I) and has a boiling point of 120 to 1
A positive photoresist composition comprising a solvent containing a compound at 80 ° C. [Chemical 1] However, n is an integer of 1 to 4, R ₁ and R ₂ are H or a methyl group or an ethyl group (provided that R ₁ and R ₂ are not a methyl group or an ethyl group at the same time), R ₃ , R ₄ represents hydrogen, an alkyl group having 1 to 6 carbon atoms, an allyl group or a benzyl group, respectively. 2. General formula (I) is ethylene glycol or propylene glycol, or 1,2- or 1,3-or 1,4.
The positive photoresist composition according to claim 1, which is a reaction product of butanediol and an aldehyde or a ketone.