JPH0721642B2 - Method for forming pattern of photosensitive polyimide - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is capable of forming a polyimide pattern having excellent heat resistance and dimensional stability as well as electrical and mechanical properties with high precision, vividness and clarity. Is about how you can
The pattern of the polyimide obtained by the method of the present invention,
In particular, semiconductors, passivation films for electronic components such as resistors, interlayer insulating films for multilayer integrated circuits, soldering protective films for printed circuits, liquid crystal alignment films, α-ray shielding films for memory devices,
It can be suitably used as an insulating film of an electrolytic capacitor, an etching resist, etc., and can be applied to other known uses of polyimide.

[Conventional technology and its problems]

Aromatic polyimide is an organic material suitable for application to electronic parts due to its heat resistance, electrical characteristics, mechanical characteristics, and the like.
Further, if photosensitivity is imparted to the aromatic polyimide, the work process is rationalized, and therefore various studies have been made on imparting photosensitivity.

As a method of imparting photosensitivity to an aromatic polyimide, a method of using a soluble precursor for imparting photosensitivity is known since aromatic polyimide is generally hardly soluble in an organic solvent.

For example, a method of chemically bonding a crosslinkable group to a soluble precursor described in JP-A-54-116216 and JP-A-54-116217, and JP-A-54-145794 and Kaisho 5
There is a method of mixing a crosslinkable monomer described in JP-A No. 7-168942.

However, in any of the above methods, it is necessary to perform imide ring closure by heat treatment after photoprocessing, in which case, dehydration accompanying imide ring closure and volume contraction due to volatilization of the crosslinkable group component cause loss of film thickness. It is an unavoidable drawback that the dimensional accuracy is deteriorated. Furthermore, the heat treatment process may cause deterioration of other electronic components or organic materials.

In order to prevent the dimensional accuracy from deteriorating due to the volume shrinkage associated with the imide ring closure, a photosensitive polyimide in which a crosslinkable group is chemically bonded to a soluble polyimide is disclosed in JP-A-58-29821 and JP-A-61-59334. Proposed in the gazette.

However, these photosensitive polyimides also inevitably suffer from deterioration in dimensional accuracy due to volume contraction due to volatilization of the crosslinkable group at high temperature, and require a complicated step for introducing the crosslinkable group. Further, the former polyimide (JP-A-58-29821) is inferior in photo-curability (photosensitivity) and requires long exposure for obtaining a precise and clear polyimide pattern.

Further, a photosensitive polyimide in which a relatively low molecular weight crosslinkable alkyl group is directly bonded to a polyimide is proposed in JP-A-58-1917 and JP-A-60-155277.

However, although these photosensitive polyimides are less likely to deteriorate in dimensional accuracy due to volume shrinkage, they are inferior in photocurability and have a drawback that long exposure is required to obtain a precise and clear polyimide pattern.

Therefore, it is an object of the present invention to provide a method capable of forming a polyimide pattern having excellent heat resistance and dimensional stability as well as electrical and mechanical properties with high precision, clearly and easily.

[Means for solving problems]

The present inventors, as a result of various studies to achieve the above objects, to an organic solvent-soluble polyimide consisting of a polycondensate of a biphenyltetracarboxylic acid component and an organic diamine component,
It was found that the composition containing a specific azide compound exhibits high photosensitivity to a specific amine compound-containing developer, even though the composition does not contain a polyimide having a crosslinking group or a crosslinking additive.

The present invention was made based on the above findings, an organic solvent-soluble aromatic polyimide consisting of a polycondensation product of a biphenyltetracarboxylic acid component and an organic diamine component, and an aromatic azide compound, organic solvent-soluble A polyimide film is formed using a photosensitive polyimide composition, the polyimide film is exposed to light in a predetermined pattern, and then a developer containing one or more compounds selected from the following group of compounds, or Developing with a developer comprising a mixture of one or more compounds selected from the following group of compounds and one or more compounds selected from the following group of compounds: A method of forming a pattern of a photosensitive polyimide is provided.

Group 1: monoethanolamine, hydrazine, (. Shown in the formula, n 3 or more _{integer) C n H 2n + 1 -NH} 2, NH 2
(Wherein, n represents an integer of 2 or _{more.) -C n H 2n -NH 2} 2 groups: detail water, pattern formation method of the photosensitive polyimide of the present invention the following alcohol compounds.

The organic solvent-soluble polyimide constituting the photosensitive polyimide composition used in the present invention is obtained by polymerizing a biphenyltetracarboxylic acid component and an organic diamine component by a known method.
It can be obtained by imidization.

The biphenyltetracarboxylic acid component used in the production of the organic-organic solvent-soluble polyimide, specifically, 3,3 ', 4,4'-biphenyltetracarboxylic acid or a dianhydride thereof, 2,2', 3,3′-biphenyltetracarboxylic acid or a dianhydride thereof, 2,3,3 ′, 4 ′,-biphenyltetracarboxylic acid or a dianhydride thereof, and the like, and among these, 2,3,3 ', 4'-Biphenyltetracarboxylic acid or its dianhydride is particularly preferable from the viewpoint of polymer solubility.

In addition, as the organic diamine component used in the production of the organic solvent-soluble polyimide, an organic diamine compound in which two amino groups are directly bonded to an aromatic ring or an aromatic heterocycle is preferable from the viewpoint of heat resistance. Examples of such organic diamine compounds include those represented by the following formula.

Among these organic diamine compounds, polycyclic aromatic diamine compounds are particularly preferable from the viewpoint of polymer solubility.

In addition, the above organic diamine compound may have a substituent such as an alkyl group, an alkoxyl group, and a hydroxyl group within a range that does not adversely affect the heat resistance of the polyimide.

As the organic diamine component, the organic diamine compounds may be used alone or in combination of two or more.

Further, in order to improve the adhesiveness of the polyimide, as long as the heat resistance is not reduced, as the organic diamine component,
Aliphatic compounds having siloxane production can also be used in combination with the above organic diamine compounds. Preferred examples of such compounds include compounds represented by the following formula.

The organic solvent-soluble polyimide used in the present invention is polyimide 0.5 g / N-methyl-2-pyrrolidone 100 ml.
The logarithmic viscosity measured at 30 ° C as a solution having a concentration of 0.
Those in the range of 1 to 3.0, especially 0.2 to 2.0 are preferable.

The production of the organic solvent-soluble polyimide used in the present invention will be described in more detail. The ratio of the biphenyltetracarboxylic acid component and the organic diamine component used when synthesizing the polycondensate is approximately equimolar. Then, both components can be synthesized by polymerizing and imidizing in a single step at a high temperature of 100 ° C. or higher. It can also be synthesized by a two-step reaction in which a polymerization reaction is first performed and then an imidization reaction is performed at a relatively low temperature.

Further, as the aromatic azide compound constituting the photosensitive polyimide composition used in the present invention, any of an aromatic monoazide compound and an aromatic polyazide compound (particularly an aromatic bisazide compound) is used, and specifically, An aromatic monoazide compound such as And other aromatic bisazide compounds.

The amount of the aromatic azide compound to be blended is 0.2 to 30 parts by weight, especially 1 to 100 parts by weight of the organic solvent-soluble polyimide.
It is preferably about 20 parts by weight. If the blending amount is less than 0.2 parts by weight, the sensitivity of the resulting composition is lowered, and
If the amount is larger than the amount by weight, the properties of the film formed by the resulting composition deteriorate.

In addition, as an example of a preferable compound represented by C _n H _{2n + 1} -NH ₂ (wherein n represents an integer of 3 or more) in the above-mentioned 1 group of compounds used as a developing solution in the present invention, Include propylamine, butylamine, etc., and NH ₂ —C _n H _2n —
Examples of preferable compounds represented by NH ₂ (wherein n is an integer of 2 or more) include ethylenediamine and trimethylenediamine.

As the alcohol compound of the compounds of the second group to be used in combination with the compound of the first group in the present invention, C _n H _{2n + 1} -O
H (in the formula, n represents an integer of 1 or more), 2-propanol, R ₁ -OCH ₂ CH ₂ OR ₂ (In the formula, R ₁ represents H or R ₂ , and R ₂
Represents CH ₃ , C ₂ H ₅ , and C ₄ H ₉ . ), R ₁ -OCH ₂ CH ₂ OCH ₂ CH ₂ OR ₂
(In the formula, R ₁ represents H or R ₂ , and R ₂ represents CH ₃ , C ₂ H ₅ , or C ₄ H _9. ) and the like.

Examples of preferred compounds represented by the above C _n H _{2n + 1} -OH include methanol, ethanol, 1-propanol, etc., and also represented by the above R ₁ -OCH ₂ CH ₂ CH ₂ OR _2. Examples of preferred compounds include ethyl cellosolve, butyl cellosolve and the like, and the above R ₁ -OCH ₂ CH ₂ OCH ₂ CH ₂ O.
Examples of preferred compounds represented by R ₂ include ethyl carbitol, butyl carbitol and the like.

As the developing solution used in the present invention, it is preferable that the compound of the first group is 20 to 100% by weight of the developing solution and the compound of the second group is 80 to 0% by weight of the developing solution.

If necessary, the developer used in the present invention may be mixed with a solvent such as N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide and hexamethylenephosamined. can do.

Thus, in carrying out the method for forming a photosensitive polyimide pattern of the present invention, first, a polyimide film is formed using the photosensitive polyimide composition.

The formation of the polyimide film can be performed, for example, as follows.

The photosensitive polyimide composition is dissolved in an organic solvent to prepare an organic solvent solution of the photosensitive polyimide composition. As the organic solvent, N, N-dimethylformamide, N, N-
Dimethylacetamide, N-methyl-2-pyrrolidone,
N-vinyl-2-pyrrolidone, dimethyl sulfoxide,
Hexamethylene phosphoamine, m-cresol and the like can be mentioned, and a mixed solvent of these solvents and xylene, ethyl cellosolve, diglyme, dioxane or the like can also be used. The preferable polymer concentration of the organic solvent solution of the photosensitive polyimide composition is 2 to 40% by weight.

The organic solvent solution of the photosensitive polyimide composition, for example, a reaction solution obtained by polymerizing and imidizing the acid component and the diamine component is added dropwise to a poor solvent, the organic solvent-soluble polyimide After precipitation and drying, the polyimide can be prepared by dissolving the polyimide at the polymer concentration in the organic solvent together with the aromatic azide compound. In addition, polymerization at a temperature of 150 ° C or higher in one step
When the imide reaction is carried out, it can also be prepared by cooling the reaction solution and then adding the aromatic azide compound to the reaction solution.

In the organic solvent solution of the above photosensitive polyimide composition, to further enhance the photosensitivity, 1-nitropyrene, 1,8-
A compound serving as a sensitizer for an azide compound such as dinitropyrene or cyanoacridine can be added.

Moreover, in order to improve the adhesiveness to the support, an adhesion aid can be appropriately added to the organic solvent solution of the photosensitive polyimide composition. Examples of such an adhesion aid include γ-methacryloxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and γ.
-Glycidoxypropyltrimethoxysilane, γ- (2
-Aminoethyl) aminopropylmethyldimethoxysilane and the like can be mentioned.

Then, the organic solvent solution of the photosensitive polyimide composition prepared as described above is applied to the substrate and dried to remove the organic solvent to obtain a polyimide film made of the photosensitive polyimide.

The application to the substrate can be performed by, for example, a spin coater. The coating film may be dried at 150 ° C or lower, preferably 100 ° C or lower. At this time, the pressure may or may not be reduced.

Next, the polyimide film obtained as described above is exposed in a predetermined pattern.

The exposure can be performed by placing a negative-type photomaster on the polyimide film and irradiating with active rays such as ultraviolet rays, visible rays, electron beams, and X-rays. At this time, when the ultraviolet rays from the high pressure mercury lamp are irradiated, the exposure amount is 30 to 50
About mJ / cm ² (measured in the 350 nm wavelength range) is sufficient.

Then, after exposure, the polyimide film is developed with the developer to obtain a photosensitive polyimide pattern.

The development can be performed by immersing the polyimide film in the developing solution to wash away the unexposed portion of the polyimide film with the developing solution.

Further, the above-mentioned development is preferably carried out at a developer temperature of 0 to 150 ° C.

The pattern of the photosensitive polyimide obtained as described above can be used as it is for the various applications described above, but is heat-treated at a temperature of about 200 ° C. to remove a trace amount of the solvent remaining in the coating film. It is preferable. Furthermore, since the pattern is formed by a photosensitive polyimide composition that does not include a polyimide having a crosslinkable group or a crosslinkable additive, there is no possibility of volume shrinkage accompanying volatilization of the crosslinkable group at high temperature, Depending on the application, heat treatment up to about 400 ° C is also possible.

〔Example〕

Hereinafter, a production example showing production of an organic solvent-soluble polyimide constituting the photosensitive polyimide composition used in the present invention, and an example of the present invention will be given together with comparative examples.

Production Example 1 Under nitrogen stream, 6.721 g of 2,3,3 ', 4'-biphenyltetracarboxylic dianhydride and 10.062 g of bis [4- (4'-aminophenoxy) phenyl] sulfone were mixed with N-methyl-2.
-Dissolved in 80 ml of pyrrolidone (NMP) and stirred at a reaction temperature of 180 ° C for 5 hours to carry out polymerization and imidization reaction. This reaction solution was dropped into methanol to precipitate a polyimide, which was filtered to obtain a polyimide powder. Logarithmic viscosity of this polyimide powder (concentration: polyimide powder 0.5g / NMP100m
l, measurement temperature: 30 ° C) was 0.85.

Production Examples 2 to 5 Polyimides having logarithmic viscosities shown in Table 1 below were obtained in the same manner as in Production Example 1 except that the polyimide synthesis conditions in Production Example 1 were changed to the conditions shown in Table 1 below.

Example 1 0.50 g of the polyimide powder obtained in Production Example 1 and 50 mg of 2-azidopyrene were dissolved in 3.67 g of NMP and then filtered through a 1 μm filter to obtain a solution of a photosensitive polyimide composition in an organic solvent.

The resulting solution was spin coated on a copper plate with a surface roughened using a spinner at 2000 rpm for 30 seconds, then at 60 ° C.
And dried for 30 minutes to obtain a polyimide film having a thickness of 3 μm.

Next, the degree of photosensitivity of this polyimide film, that is, the sensitivity was measured as follows.

On the polyimide film, gray scale (manufactured by Kodak Co.,
Photographic Step tablet no.2 21 STEPS)
Ultraviolet rays were irradiated for 30.3 seconds from a distance of 70 cm by a 2 Kw ultra-high pressure mercury lamp (Jetlight, manufactured by Oak Manufacturing Co., Ltd.). This polyimide film was developed with monoethanolamine heated to 60 ° C, and the number of remaining film steps was taken as the sensitivity. In this measurement, 35 transmitted through each grayscale step
The UV irradiation dose (mJ / cm ² ) in the wavelength range of 0 nm is shown in Table 3 below.
(The measurement is made by Oak Manufacturing Co., Ltd. UV illuminometer UV
-M01 was used). The polyimide film was cured up to the 11th dose.

Examples 2 to 13 and Comparative Examples 1 to 2 Photosensitive polyimide compositions of the present invention were prepared in the same manner as in Example 1 except that polyimide, organic azide compound and developer shown in Table 2 below were used. Each of the organic solvent solutions was obtained, and the sensitivities of the polyimide films (thickness 2 to 3 μm) made of these solutions were measured. The results are shown in Table 2 below.

Example 14 A glass substrate whose surface was coated with SiO ₂ was treated with a 0.3% 2-propanol solution of a silane coupler [KBM603: 6- (2-aminoethyl) aminopropyltrimethoxysilane manufactured by Shin-Etsu Scientific Co., Ltd.] in 2500 rpm. It was spin coated for 30 seconds. This coupler solution coated substrate was air dried at room temperature for 3 minutes, then 150
The substrate was heat-treated at 10 ° C. for 10 minutes to perform coupler treatment on the substrate.

On the other hand, 1.1 g of the polyimide powder obtained in Production Example 1 and 4-
0.11 g of azidobenzalacetophenone was dissolved in 8.9 g of NMP and then filtered through a 1 μm filter to obtain a solution of a photosensitive polyimide composition in an organic solvent.

The resulting solution was spin-coated on a glass substrate that had been subjected to the above-mentioned coupler treatment using a spinner at 2500 rpm for 30 seconds, and then this coating film was dried by heating at 70 ° C. for 30 minutes, and 1.
A 9 μm thick polyimide film was obtained. A 250 W high-pressure mercury lamp (Mikasa Co., Ltd.) was passed through this polyimide film through a test mask (Toppan Test Chart P, Toppan Printing Co., Ltd.).
The mask alignment device MA-10 type was used) for 4.6 seconds. UV intensity on exposed surface is 6.5mW / cm in 350nm wavelength range
² (measurement was done using the same luminometer as used in Example 1), ie 30 mJ / cm ² exposure. After exposure, it was developed with monoethanolamine heated to 60 ° C., and then washed with room temperature monoethanolamine and then room temperature 2-propanol to obtain a photosensitive polyimide pattern. If the smallest master pattern that can be identified by the obtained pattern is defined as the resolution, the resolution of this pattern is 3
It had a sharp end face. The polyimide film thickness after development was 1.4 μm.

This pattern is then heated at 150 ° C for 30 minutes, then 200
When the residual solvent in the pattern was removed by heating at 30 ° C. for 30 minutes, the film thickness was 1.2 μm. Next, when this pattern was heated at 300 ° C. for 30 minutes in a nitrogen stream and then at 400 ° C. for 30 minutes, the film thickness was 1.1 μm. Even after heating at 400 ° C., the pattern had no deformation or blurring and had good heat resistance.

Examples 15 to 17 An organic solvent solution of a photosensitive polyimide composition was obtained in the same manner as in Example 14 except that the polyimide obtained in Production Example 1 was used and the compounding composition shown in Table 4 below was used. Using this solution, pattern formation and heat treatment were performed in the same manner as in Example 14. The developing solution used monoethanolamine in all of Examples 15 to 17, but in Examples 15 and 16,
The developer heated to 65 ° C. was used, and in Example 17, the developer heated to 60 ° C. was used. In addition, the number of coating rotations when coating the organic solvent solution of the photosensitive polyimide composition on the substrate was the number of coating rotations shown in Table 5 below.

The results of the above pattern formation and heat treatment are shown in Table 5 below. In any of Examples 15 to 17, a photosensitive polyimide pattern having a sharp end face was obtained, and 400
The pattern did not show any deformation or blur even after heat treatment up to ℃, and had good heat resistance.

In the systems whose sensitivity was measured by the gray scale method in Examples 2 to 5 and Examples 10 to 13, exposure to 30 to 50 mJ was performed using a test mask, and development was performed under the respective development conditions of the gray scale method. A pattern was formed with the same resolution as in Examples 14 to 17. When these patterns were subjected to a heat treatment up to 400 ° C. in the same manner as in Example 14, the film thickness was changed to the same extent as in Examples 14 to 17, and no pattern deformation or blurring was observed. . On the other hand, in Comparative Examples 1 and 2, the pattern could not be obtained because the polyimide film could not be developed.

In the conventional method, the exposure of the polyimide film required an exposure amount of 100 mJ / cm ² or more, as compared with the results shown in Table 5 below, according to the method of the present invention, 30 to 50 mJ / cm ² c
It can be seen that a pattern can be obtained with a small exposure amount of m ^{2, and} that the pattern obtained by the method of the present invention has little change in film thickness even after a high temperature process and is excellent in dimensional stability.

EFFECT OF THE INVENTION According to the method for forming a photosensitive polyimide pattern of the present invention, a polyimide pattern having excellent heat resistance and dimensional stability as well as excellent electrical and mechanical properties can be clearly and easily formed with high accuracy. Can be formed.

Claims (1)

[Claims] 1. An organic solvent-soluble photosensitive polyimide composition comprising an organic solvent-soluble aromatic polyimide composed of a polycondensate of a biphenyltetracarboxylic acid component and an organic diamine component and an aromatic azide compound is used. After forming a polyimide film and exposing the polyimide film in a predetermined pattern, a developer composed of one or more compounds selected from the compound group of the following one group, or selected from the compound group of the following one group A method for forming a pattern of a photosensitive polyimide, which comprises developing with a developer comprising one or more compounds selected from the group consisting of two or more compounds and one or more compounds selected from the following two groups of compounds. Group 1: monoethanolamine, hydrazine, (. Shown in the formula, n 3 or more _{integer) C n H 2n + 1 -NH} 2, NH 2
(Wherein, n represents an integer of 2 or _{more.) -C n H 2n -NH 2} 2 group: water, alcohol compounds