JP2000098601A - Positive type photosensitive polyamic acid composition and pattern forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a positive type photosensitive polyamic acid composition which gives a pattern having good resolution, does not require post-exposure heating for development, is easily prepared in a simple system and has good shelf stability by incorporating a specified polyamic acid and an o- quinonediazido compound. SOLUTION: The photosensitive polyamic acid composition contains a polyamic acid of the formula [where (n) is a positive integer] and an o- quinonediazido compound. The polyamic acid is obtained, e.g. by polymerizing 4,4'-oxydiphthalic acid dianhydride and 2,2-bis(4-aminophenyl)hexafluoropropane in a molar ratio of 80:10O to 100:80 in an organic solvent such as N-methyl-2- pyrrolidone or N,N-dimethylformamide. The o-quinonediazido compound preferably contains two or more o-quinonediazido groups in one molecule.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positive photosensitive polyamic acid composition, and more particularly, to a polyimide-based heat-resistant polyamic acid composition which can be applied as a surface protective film, an interlayer insulating film and the like of electronic parts such as semiconductor devices by heat treatment. The present invention relates to a positive photosensitive polyamic acid composition to be a resin. Further, the present invention relates to a resin using a positive photosensitive polyamic acid composition.
The present invention relates to a method for forming a pattern.

[0002]

2. Description of the Related Art Polyimide has advantages such as excellent heat resistance, mechanical properties, and electrical insulation, as well as easy film formation and flattening of the surface. Widely used for electronic parts. On the other hand, in order to streamline work processes and improve film formation accuracy,
Various studies have been made on imparting photosensitivity.

[0003] For example, Japanese Patent Application Laid-Open No. Sho 64-60630,
JP-A-3-209478 describes that a composition containing a polyimide having a hydroxy group or the like introduced into an aromatic ring and orthoquinonediazide can be developed with an aqueous alkali solution. However, since a large amount of a photosensitive substance must be added to increase the sensitivity, or an acidic group remains in the polymer, heat resistance, electrical characteristics,
There is a problem with alkali resistance.

Japanese Patent Application Laid-Open No. 52-13315 describes a photosensitive polyamic acid composition of polyamic acid and orthoquinonediazide. However, there is a problem that the residual film ratio after the development is low and the allowable development width (the allowable width of the development time) is narrow.

Japanese Patent Application Laid-Open No. 62-135824 (JP-B-6-135824)
No. 52426) discloses an example in which an orthoquinonediazide compound is mixed with a polyamic acid and partially imidized by adjusting the prebaking temperature to reduce the acidity of the polyamic acid and perform patterning. . However, a large amount of a photosensitizer must be added, and the resulting film has problems in heat resistance and electrical characteristics.

JP-A-5-5996 discloses a pattern in which a photosensitive polyamic acid composition of various combinations of a polyamic acid and an orthoquinonediazide compound is heated after exposure to form a relief pattern. A method is described. However, since the polyamic acid described as an example in the publication is too soluble in a normal developing solution to form a relief pattern, a complicated process of patterning by heat treatment after exposure is required. Is done. Furthermore, in this relief pattern forming method, the condition setting is delicate.
It is pointed out that it is difficult to adopt the method when it is implemented industrially.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a photosensitive polyamic acid composition which does not have the above-mentioned problems. Another object of the present invention is to provide a relief pattern forming method which does not have the above-mentioned problems.

[0008]

That is, the present invention provides:
(A) The following formula (1)

[0009]

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A positive photosensitive polyamic acid composition comprising a polyamic acid represented by the formula (where n is a positive integer) and (b) an orthoquinonediazide compound. The present invention also provides a step of applying the positive photosensitive polyamic acid composition on a substrate to form a resin layer, exposing a desired region of the resin layer, and developing the resin layer after the exposure. And a step of heating the developed resin layer to imidize the polyamic acid in the resin layer.

The positive photosensitive polyamic acid composition of the present invention has a good pattern resolution, does not require post-exposure baking (also called PEB) for development, is simple, and can be easily manufactured. It has good storage stability and has practical sensitivity even at i-line. Further, the relief pattern of the present invention
The pattern forming method has a simple process and has good film physical properties.

The polyamic acid (a) in the present invention is, for example, 4,4'-oxydiphthalic dianhydride and 2,4'-oxydiphthalic dianhydride.
It is obtained by polymerizing 2-bis (4-aminophenyl) hexafluoropropane in an organic solvent at a molar ratio of 80: 100-100: 80, preferably 90: 100-100: 90. In addition to the above-mentioned acid dianhydride and diamine components, other tetracarboxylic dianhydrides and diamines may be copolymerized within a range that does not significantly change the solubility in a developer. This copolymerization may be either random or block.

The other acid dianhydrides and diamines have a substituent such as an alkyl group or an alkoxyl group in the aromatic ring as long as the heat resistance of the finally produced polyimide is not adversely affected. It may be. In particular, in order to improve the adhesiveness, it is preferable to use a diamine which is an aliphatic compound having a siloxane structure as the diamine as long as the heat resistance is not reduced. Preferred examples of this compound include the following formula (3)

[0014]

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[R ₃ is a divalent hydrocarbon residue, R ₄ is methyl, ethyl, phenyl, and m is an integer of 1-20 (particularly 1). The diamino (poly) siloxane shown by these] is mentioned.

As the organic solvent, N-methyl-2
-Pyrrolidone (NMP), N, N-dimethylformamide, N, N-dimethylacetamide, dimethylsulfoxide, hexamethylphosphoramide, tetramethylene sulfone, γ-butyrolactone, p-chlorophenol, and the like. Further, a mixed solvent of any of these and ethyl cellosolve, butyl cellosolve, propylene glycol mono-n-butyl ether, diglyme, dioxane, xylene, or the like can also be used.

Examples of the other tetracarboxylic dianhydride include 2,3,3 ', 4'-biphenyltetracarboxylic dianhydride and 3,3', 4,4'-biphenyltetracarboxylic dianhydride. Anhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 3,3 ′, 4
4'-biphenylsulfonetetracarboxylic dianhydride,
Examples thereof include pyromellitic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, and cyclobutanetetracarboxylic dianhydride.

As the other diamine, for example,
3-bis (3-aminophenoxy) benzene, 1,3-
Bis (4-aminophenoxy) benzene, 1,4-bis (3-aminophenoxy) benzene, 1,4-bis (4
-Aminophenoxy) benzene, 1,3-bis (3-aminobenzoyl) benzene, 1,4-bis (3-aminobenzoyl) benzene, 1,3-bis (4-aminobenzoyl) benzene, 1,4-bis (4-aminobenzoyl) benzene, 3,3'-diamino-4-phenoxybenzophenone, 4,4'-diamino-5-phenoxybenzophenone, 3,4'-diamino-4-phenoxybenzophenone, 3,4'-diamino -5-phenoxybenzophenone, 1,4-bis (p-aminocumyl) benzene, 1,3-bis (p-aminocumyl) benzene,
1,4-bis (m-aminocumyl) benzene, 1,3-
Bis (m-aminocumyl) benzene, 4,4 "-diamino-p-tert-phenyl, 4,4" -diamino-m-tert-phenyl
Phenyl, 3,3 "-diamino-p-tert-phenyl,
3,3 "-diamino-m-ta-phenyl, m-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone ,
4,4'-diaminodiphenyl sulfide, benzidine, 1,5-naphthalenediamine, 2,6-naphthalenediamine and the like can be mentioned. The other tetracarboxylic dianhydride and diamine are 20% by weight in the copolymer.
Preferably, the ratio is as follows.

The (b) orthoquinonediazide compound in the present invention is defined as having an orthoquinonediazide group in the molecule.
Compounds containing more than one are preferred. Examples of such a compound include an orthobenzoquinonediazide compound, an orthonaphthoquinonediazide compound, an orthoquinolinediazide compound, and an orthonaphthoquinonediazide compound is particularly preferable. The above-mentioned orthoquinonediazide compound is usually preferably used as orthoquinonediazidesulfonic acid ester. This orthoquinonediazidesulfonic acid ester is usually obtained by a condensation reaction between orthoquinonediazidosulfonic acid chloride and a compound having a hydroxyl group.

Examples of the orthoquinonediazidesulfonic acid component constituting the above-mentioned orthoquinonediazidesulfonic acid chloride include 1,2-naphthoquinonediazide-4-sulfonic acid and 1,2-naphthoquinonediazide-5-sulfonic acid. Examples of the compound having a hydroxyl group include catechol, hydroquinone, 2,4-dihydroxybenzophenone, 2,3,4-trihydroxybenzophenone, 2,3,4,4′-tetrahydroxybenzophenone, 2,2 ', 4,4'-tetrahydroxybenzophenone, 3,3', 4,4'-tetrahydroxybenzophenone, 2,2-bis (4-hydroxyphenyl) propane, tris (4-hydroxyphenyl) methane, 1,1 , 1-Tris (4-hydroxyphenyl) ethane, 4,4′-dihydroxyphenylsulfone, α, α, α′-tris (4-hydroxyphenyl)
-1-ethyl-4-isopropylbenzene and the like.

The positive photosensitive polyamic acid composition of the present invention comprises (b) an orthoquinonediazide compound in an amount of 1 to 40 parts by weight, preferably 5 to 40 parts by weight, based on 100 parts by weight of the polyamic acid.
It is preferable to use -30 parts by weight. If the amount is less than 1 part by weight, the sensitivity of the photosensitive polyamic acid composition obtained will be low, and if it is more than 40 parts by weight, the properties of the film formed from the obtained positive type photosensitive polyamic acid composition will be deteriorated. . In this case, the polyamic acid is preferably used as it is as the reaction solution. The positive photosensitive polyamic acid composition of the present invention may optionally contain an adhesion aid in order to improve the adhesion to the support. Further, by dissolving the above-mentioned (a) polyamic acid and (b) the orthoquinonediazide compound, and dissolving an adhesion aid as necessary, and performing a filtration treatment as necessary, a positive-type photosensitive polyamic acid solution is obtained. Can be prepared.

Examples of the adhesion aid include γ-methacryloxypropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidyl Xypropyltriethoxysilane, N
-Β (aminoethyl) γ-aminopropylmethyldimethoxysilane and the like.

The method for forming a relief pattern according to the present invention comprises the steps of applying the above-mentioned positive photosensitive polyamic acid composition on a substrate to form a resin layer, and exposing a desired region of the resin layer to light. And a step of developing the resin layer after the exposure, and a step of heating the developed resin layer to imidize the polyamic acid in the resin layer.

For example, first, the above-mentioned positive photosensitive polyamic acid solution is applied to a substrate (for example, a silicon wafer) and dried to remove the organic solvent. How to apply to the substrate. For example, it can be performed by a spin coater. When a hot plate is used, drying of the coating film is performed at 130 ° C. or less,
In particular, it is preferable to carry out at 120 ° C. or lower. At this time, the pressure may or may not be reduced. After drying, a positive photomask is placed on the coating, and the coating is irradiated with actinic rays such as ultraviolet rays, visible rays, and electron beams. Among them, ultraviolet and visible light having a short wavelength, that is, those having a wavelength of 200 to 500 nm are preferable. Next, the exposed portion is washed away with a developing solution to obtain a polyamic acid positive-type relief pattern.

As the developer, an alkaline aqueous solution is used. Examples of the alkaline aqueous solution include an inorganic alkaline aqueous solution such as sodium hydroxide, potassium hydroxide, and sodium silicate; N, N-dimethylethanolamine;
N, N-diethylethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, Nn
Preferred examples thereof include aqueous organic alkali solutions such as -butyldiethanolamine, N-tert-butyldiethanolamine, triethanolamine, tetramethylammonium hydroxide, and choline.

Further, an alcohol or a surfactant may be added to the above-mentioned developer for use. The developer temperature may be room temperature, or to adjust the dissolution time of the exposed part,
In order to keep the developer temperature constant, in the range of 0-80 ° C,
Preferably, it can be adjusted in the range of 0-50 ° C.

Thereafter, the obtained relief pattern is
Heat treatment is performed at a temperature of 0 to 450 ° C. to imidize the polyamic acid to obtain a polyimide pattern.

[0028]

Embodiments of the present invention will be described below. In the following description, “part” indicates “part by weight” and “%” indicates “% by weight”.

Production Example 1 To 54.27 g of a mixed solvent of NMP / propylene glycol mono-n-butyl ether = 8/2 (weight ratio), 1
0.346 g of 3-bis (3-aminopropyl) tetramethyldisiloxane, 1 of 4,4′-oxydiphthalic acid
2.651 g of a 9.53% NMP solution, 2,2-bis (4
-Aminophenyl) hexafluoropropane 8.836
g was dissolved. While stirring the solution, 8.114 g of 4,4'-oxydiphthalic dianhydride powder was added over about 5 minutes. After stirring this solution at room temperature (23 ° C.) for 24 hours,
Left for 2 weeks at room temperature. The logarithmic viscosity of the obtained polyamic acid was 0.30.

Example 1 A solution of a silane coupler (KBM903: γ-aminopropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.) in 0.5% ethanol / water = 95/5 (weight ratio) was placed on a silicon wafer. Spin coating was performed at 3000 rpm for 30 seconds. After air-drying the substrate coated with the coupler solution at room temperature for 3 minutes,
Heat treatment was performed at 250 ° C. for 5 minutes on a hot plate to perform a coupler treatment on the wafer. On the other hand, the polyamic acid solution obtained in Production Example 1 (polymer content: 24.0%)
After dissolving 0.600 g of the oritoquinonediazide compound (shown by the following formula) in 0 g, the solution was filtered through a 1 μm filter to prepare a photosensitive polyamic acid solution.

[0031]

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The obtained solution was applied to a silicon wafer which had been subjected to the above-mentioned coupler treatment on a silicon wafer at 1700 r using a spinner.
pm for 30 seconds and then heat dried at 120 ° C. for 2 minutes on a hot plate to give 8.2 μm
A thick coating was obtained. 25
Light of a 0 mW high-pressure mercury lamp [Mikasa Corporation, mask alignment device MA-10] was applied for 96.8 seconds.
The UV intensity on the exposed surface is 6.2 mW in the 350 nm wavelength range.
/ Cm ² [Oak Manufacturing Co., Ltd., UV illuminometer UV
-M01], ie, 600 mJ / cm ²
You have been exposed.

After the exposure, the resist film was developed with a 2.38% aqueous solution of tetramethylammonium hydroxide (TMAH) at room temperature (about 23 ° C.) for 40 seconds, and then purified water, a 1% aqueous acetic acid solution and pure water in the order of 30 minutes. After rinsing for 2 seconds, a positive relief pattern was obtained. If the minimum mask pattern that can be identified by the obtained positive relief pattern is defined as the resolution, the resolution of this pattern is 6 μm, and the
Had a sharp end face. The residual film thickness of the unexposed portion after the development for 40 seconds was 6.2 μm, and the residual film ratio was 76%.

On the other hand, when the coating film after the exposure was separately developed and rinsed under the same conditions as above except that the developing time was 90 seconds, the resolution was 6 μm and the remaining film thickness of the unexposed portion was 6.1 μm.
m (residual film ratio: 74%) was obtained as a sharp relief pattern.

Next, the pattern for a developing time of 40 seconds is set to 1
When heated at 70 ° C. and 250 ° C. for 30 minutes each, and then heated at 350 ° C. for 30 minutes under a nitrogen stream, the film thickness was 5.0 μm.
Met. Even after heating at 350 ° C., this pattern film is deformed,
The film had good heat resistance without any blurring or the like. The heat resistance of this pattern film was evaluated by a thermogravimetric reduction measurement (manufactured by Seiko Electronics Co., Ltd., using SSC5200).
The% reduction temperature was 470 ° C and the 5% reduction temperature was 500 ° C. When a heat treatment similar to that described above was performed on the pattern for a developing time of 90 seconds, the film thickness became 4.9 μm, and the pattern after heating showed good heat resistance without deformation or blurring. Had.

When the positive type polyamic acid photosensitive solution prepared in Production Example 1 was stored for one month and then treated in the same manner, substantially no change was observed in the residual film ratio and the pattern film.

Example 2 A color glass filter was attached to the exposure apparatus of Example 1,
Patterning was performed by performing the same operation as in Example 1 except that only the i-line light was exposed to 800 mJ / cm ² , and the same result as in Example 1 was obtained.

[0038]

According to the present invention, the following effects can be obtained. The positive photosensitive polyamic acid composition of the present invention has a good pattern resolution and post-exposure baking (PE) for development.
Also called B. ) Is unnecessary, it is easy to manufacture with a simple system, has good storage stability, and has practical sensitivity even at i-line.

The method for forming a relief pattern according to the present invention has a simple process and good physical properties of the obtained pattern.

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Claims (2)

[Claims] (A) The following formula (1): (Wherein n is a positive integer) and a positive photosensitive polyamic acid composition comprising (b) an orthoquinonediazide compound. 2. A step of applying the positive photosensitive polyamic acid composition according to claim 1 on a substrate to form a resin layer, a step of exposing a desired area of the resin layer, and a step of exposing the resin layer after the exposure. And a step of heating the developed resin layer to imidize polyamic acid in the resin layer to form a relief pattern.