JPH04289865A - Manufacture for wiring structure - Google Patents

Abstract

PURPOSE:To perform patterning highly accurately and easily of a polyimide film by constituting it patterned with a resist pattern, consisting of specific polyorganosilsesquioxine, serving as a mask. CONSTITUTION:A silicon resist is formed by applying polyorganosilsesquioxine, represented by a formula I, onto a preformed polyimide film, exposed in a pattern of far ultraviolet rays and developed to obtain a pattern of the silicon resist. This pattern of the silicon resist serves as a mask to form a polyimide film patterned by etching the polyimide film of foundation. In the formula I, it represents an alkynyl group of 2 to 4 carbon number by R1, aromatic group by R2, alkynyl group and aromatic group, of 2 to 4 carbon number by R3, R4, respectively independent hydrogen atm, alkyl group of 1 to 4 carbon number, etc., by R5 to R8 and integers of 1 to 100 by (m), (n).

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a wiring structure, and more specifically, to a method of manufacturing a wiring structure having a patterned polyimide film using a specific polyorganosilsesquioxane as a resist. . A patterned polyimide film is particularly useful as an insulating film constituting the wiring structure of semiconductor devices, etc.
Further, according to the present invention, finer patterning is possible. The wiring structure of the present invention can also be used for circuit boards and display devices.

0002

[Background Art] With the increase in speed of large computers, LS
As with semiconductor components such as I and IC, the density of circuit boards for mounting these is progressing, and in particular, multilayering is becoming necessary even in thin film circuit boards using polyimide. Here, in order to form a multilayer substrate using a polyimide film as an insulating layer, it is necessary to pattern the polyimide film after forming it.
As a method of patterning a polyimide film, the following operations are performed. (1) Substances that are not imidized (polyamic acid)
A film is formed in advance, an alkali-developable positive resist is applied onto the film, and after exposure of the resist, patterning of the alkali-soluble polyamic acid is performed at the same time as the development of the resist. (2) Forming a SiO2 film or a metal thin film on the pre-formed polyimide film by sputtering or vapor deposition,
Furthermore, a resist is applied on top of that. After the resist is formed, the SiO2 film or metal thin film is patterned by a normal photolithography process. Next, using the patterned SiO2 film or metal thin film as a mask, the polyimide film is patterned by dry processing.

However, the method for patterning polyimide films as described above has several drawbacks. for example,(
In method 1), it is necessary to process a polyamic acid film with a thickness of several tens of micrometers by wet processing using a resist as a mask, making it difficult to control pattern dimensions and making it difficult to create fine patterns. is not applicable. Furthermore, method (2) requires several dry treatments, resulting in a very complicated process. Simplification of the process is desired.

[0004] When processing a polyimide film with high dimensional accuracy, the simplest method is to apply a resist onto a preformed polyimide film, expose and develop the resist, and then use the resulting patterned resist as a mask. This is a method of dry etching a polyimide film. When using conventional resist materials for the resist, it is difficult to obtain a selectivity with polyimide, so in order to process a polyimide film of several tens of micrometers, a resist with the same thickness is required. Become. However, when a conventional resist material is used with a thickness of several tens of micrometers, the exposure light is absorbed by the resist and does not reach the bottom of the resist, making it impossible to obtain a rectangular resist pattern.

[0005]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an improved method for manufacturing a wiring structure that enables fine patterning of a polyimide film with high dimensional accuracy and in a simplified manner. There is a particular thing.

[0006]

[Means for Solving the Problems] According to the present invention, when manufacturing a wiring structure having a patterned polyimide film, the above-mentioned object is obtained by applying the following formula (I) to a polyimide film formed in advance. Polyorganosilsesquioxane:

[0007]

[Case 2]

(In the above formula, R1 represents an alkenyl group having 2 to 4 carbon atoms, R2 represents a substituted or unsubstituted aromatic group such as a phenyl group, and R3 and R4 each independently represent an alkenyl group having 2 to 4 carbon atoms. ~4 alkenyl group or substituted or unsubstituted aromatic group, R5, R6,
R7 and R8 each independently represent a hydrogen atom, or a trisubstituted silyl group substituted with an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 4 carbon atoms, or a substituted or unsubstituted aromatic group, (for example, trimethylsilyl group, and m and n each represent an integer from 1 to 10,000) to form a silicone resist, exposing the silicone resist to a pattern of deep ultraviolet rays, and developing the exposed silicone resist. This can be achieved by a method for producing a wiring structure, which is characterized by: obtaining a silicone resist pattern using the silicone resist pattern, and using the silicone resist pattern as a mask, etching the underlying polyimide film to form a patterned polyimide film. .

[0009]

[Operation] As a result of intensive research to find a resist suitable for achieving the above-mentioned purpose, the present inventors independently found the following:
Alternatively, when used in combination with a photosensitizer, polyorganosilsesquioxane ( The present invention was completed based on the knowledge that the method (see Japanese Patent Application Laid-Open No. 2-99955) can be advantageously used as a resist in processing polyimide films. That is, JP-A-2-99955
According to the recent findings of the present inventors, the polyorganosilsesquioxane described in the publication has much higher resistance to plasma during dry etching than polyimide, and furthermore, this photosensitive silicone compound By using it as a resist during polyimide film processing, it becomes possible to easily pattern the polyimide film with good dimensional accuracy. Further, in the present invention, by using deep ultraviolet rays as the exposure light source, it is possible to avoid the use of a photosensitizer, which is a consideration for achieving photosensitivity in a wider ultraviolet region with long wavelengths.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS In carrying out the present invention, the preformed polyimide film can be formed from polyimide commonly used in the manufacture of wiring structures by a conventional method such as spin coating. The thickness of the polyimide film can also be selected from a wide range depending on the configuration of the device.

After forming the polyimide film, polyorganosilsesquioxane represented by the above formula (I) is applied to form a silicone resist. The polyorganosilsesquioxane used here is soluble in many organic solvents, so it can be formed into a film by conventional spin coating, and it also has excellent adhesion to polyimide, making it easy to form a film. A film can be formed on a polyimide film. Furthermore, since it has much better dry etching resistance than polyimide, it can be used in thin films, has good light transmission, and can form rectangular patterns with high dimensional accuracy. Therefore, the polyimide film can be easily patterned without going through complicated steps. This polyorganosilsesquioxane can be synthesized according to commonly used polymerization methods, as will be specifically explained in the following examples.

Next, the formed silicone resist is exposed to deep ultraviolet light in a desired pattern and developed. This process can be carried out according to conventional lithography techniques,
Further, in order to develop the exposed silicone resist, a developer such as methyl isobutyl ketone (MIBK) can be used. A fine pattern of silicone resist firmly adhered to the polyimide film is obtained.

Subsequently, the underlying polyimide film is etched using the obtained silicone resist pattern as a mask. For this etching, for example, O2RIE (
Conventional dry etching techniques such as reactive ion etching (reactive ion etching) can be used. The resist pattern used as a mask is transferred onto the base to obtain a fine polyimide pattern having a film thickness on the order of several tens of micrometers.

Example 1 Synthesis of silylated polyorganosilsesquioxane 100
18 ml of methyl isobutyl ketone (MIBK)
of pyridine was added and cooled to -60°C. 13 ml of vinyltrichlorosilane, 16 ml of phenyltrichlorosilane, and 18 ml of ion-exchanged water were sequentially added dropwise to the resulting mixture, and the temperature of the reaction solution was gradually raised. Next, a condensation polymerization reaction was carried out at 120° C. for 5 hours while bubbling nitrogen gas. After the reaction is completed, the obtained reaction solution is
It was washed with water six times, and the MIBK layer was separated. Next, the fractionated M
30 ml of trimethylchlorosilane and 30 ml of IBK layer
ml of pyridine was added and heated at 60° C. for 3 hours. This heating silylated unreacted hydroxyl groups. Next, the reaction solution was washed with water 10 times and poured into acetonitrile to precipitate and recover the silylated polyorganosilsesquioxane. The obtained resinous material was dissolved in 50 ml of benzene and freeze-dried. The silylated polyorganosilsesquioxane obtained in this synthesis example had a weight average molecular weight of 5.0×10 4 and a dispersity of 1.8.

Example 2 Formation of a through-hole pattern in a polyimide film A resin solution was prepared by dissolving 2 g of the silicone resin obtained in Example 1 in 8 g of MIBK. The obtained resin solution was spin-coated to a thickness of 1 μm on a polyimide film formed on a glass substrate to a thickness of 30 μm, and then heated at 80°C for 2 hours.
Solvent drying was performed for 0 minutes. Next, the obtained silicone resin film (resist) was exposed to deep ultraviolet light through a mask, developed with MIBK, and further rinsed with isopropyl alcohol. A desired resist pattern was obtained. After forming the resist pattern, the substrate to be processed was set in a parallel plate type dry etching apparatus, and the polyimide film was etched by O2RIE using oxygen plasma. Furthermore, the substrate to be processed was immersed in a 2.5% hydrofluoric acid buffer to remove the silicone resist. As a result, a 3 μm through hole pattern could be formed in the polyimide film with an exposure dose of 100 mJ.

[0016]

As is clear from the above description, according to the present invention, polyimide films can be easily and finely processed with high dimensional accuracy. The field of use can be expanded advantageously. Further, according to the present invention, the silicone resist used as a mask when patterning the polyimide film can be formed by a conventional spin coating method, and has the advantage of having excellent adhesion to the polyimide film.

Claims (1)

[Claims] 1. In manufacturing a wiring structure having a patterned polyimide film, a polyorganosilsesquioxane represented by the following formula (I): In the formula, R1 represents an alkenyl group having 2 to 4 carbon atoms, R2 represents a substituted or unsubstituted aromatic group, and R
3 and R4 each independently represent an alkenyl group having 2 to 4 carbon atoms or a substituted or unsubstituted aromatic group, and R5, R6, R7 and R8 each independently represent a hydrogen atom. or represents an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 4 carbon atoms, or a 3-substituted silyl group substituted with a substituted or unsubstituted aromatic group, and m and n each represent an integer of 1 to 10,000. ) is applied to form a silicone resist, the silicone resist is exposed to a pattern of deep ultraviolet rays, the exposed silicone resist is developed to obtain a silicone resist pattern, and the silicone resist pattern is used as a mask to form a silicone resist. 1. A method for manufacturing a wiring structure, comprising etching a polyimide film to form a patterned polyimide film.