JPS61208050A - Formation of conductive film pattern - Google Patents

Abstract

PURPOSE:To enable a micropattern appliable to a dot matrix to be formed by masking a conductive film formed on a film with a photosensitive resist and after exposure to a prescribed pattern and heat development, etching it. CONSTITUTION:The conductive film made of SnO2, or In2O3, is vapor deposited on a polymer film and it is masked with a photosensitive resist film of a water- soluble type, and it is exposed by using a fine photomask for displaying a micropattern of 30-100mum. After exposure, it is heat treated at 40 deg.C for about 2min, and the unexposed parts are dissolved off with an aq. alkaline soln., and etched with an aq. 25% hydrochloric acid soln., thus permitting an etching pattern as fine as about 40mum to be formed by heat treatment after exposure.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for forming a pattern of conductive film,
Specifically, the present invention relates to a method for forming metal or pufferfish formed by vapor deposition or the like on a polymer film as a substrate.

The conductive polymer film, which has a conductive thin film on the polymer film, can be used for wiring boards, heaters, touch panel electrodes,
Or i! for LCD display! It is possible to use it for poles, etc., but generally, in order to use it for such purposes, a necessary part of the conductive film is left over a wide area, usually the entire surface.

Other parts may need to be dissolved and removed, ie, etched into a predetermined pattern.

Recently, the development of liquid crystal display elements using conductive polymer films as electrodes has been actively conducted, but especially in the case of dot matrix display types, the electrode pattern can be processed to extremely fine #I (thin lines of 30 to 50 μm). It's becoming necessary.

(Prior Art) As a method of etching a conductive film formed on a substrate, conventionally, a mask is first formed in a predetermined butterfly shape on a conductive thin film using the Nuclean printing method and the photoresist method. A method is used in which the patterned mask is then etched and then dissolved and removed using a release agent.

Comparing the resolution, workability, etc. of conventional rib pattern forming methods, for example, in the screen printing method, a masking agent is applied in a pattern on a conductive film using a predetermined patterned printing plate, and then etched. , a predetermined pattern is formed, but the resolution is limited to 300 μm due to the mesh of the screen plate, making it extremely unsuitable for forming ultra-fine patterns (30 to 50 μm) such as those used as electrodes for Dobutomatori and Nokunu displays. be. The photoresist method includes coating type and resist/resist method.
There is also a film-attached type. In this case, unlike the coating type using a screen plate, there is no fundamental problem regarding resolution, and even fairly thin patterns can be formed. Therefore, the resist-coated type has traditionally been widely used for Nesa glass, but when the substrate is replaced with a polymer film, the adhesion with the conductive film is generally poor. It is difficult to form fine patterns. In particular, in addition to the poor adhesion between the semiconductor made of indium-tin oxide and the film resist, it has been difficult to form accurate fine patterns.

For the above reasons, there has been a desire to develop a method for forming fine dobutatolithography patterns (30 to 50 Pm) for polymer films.

(Objective of the Invention) The present inventors aim to develop a method for etching a conductive film finely so that it can be used as an electrode for dot matrix display and without line irregularities.

(Structure of the Invention) That is, the present invention involves masking the conductive film of a polymer film having a conductive film on the surface with a photosensitive resist, exposing it to light in a predetermined pattern, heating it, developing it, and then etching it. This is a characteristic pattern forming method for conductive films.

Although heating in the method of the present invention may be performed at room temperature or above, the practical upper limit is limited by the polymer film of the substrate. The processing temperature cannot be determined by the absolute value of the temperature, but it is essential that the room temperature is higher than the temperature at the time of exposure. In the case of polyethylene terephthalate film, which is a typical substrate, the temperature is about 30°C to 60°C, preferably about 40°C. At such temperatures, the processing time required to achieve the objectives of the present invention is between 2 and 3 minutes.

Examples of the conductive film of the present invention include metal thin films such as silver, copper, and aluminum, and metal oxide thin films such as tin oxide and indium oxide. These thin films are usually applied by vapor deposition or the like, and their thickness is preferably 100 OA or less. The vapor deposition methods include vacuum vapor deposition, RF and DC.
Any method such as sputtering or ion blating may be used.

Any type of photosensitive resist may be used. These are usually divided into two types based on the development method: the solvent type, which removes the unexposed areas with a solvent, and the water-soluble type, which removes the unexposed areas with a water-based product, but there is no difference in the photosensitive mechanism. , either type may be used in the present invention. The baking method may be selected depending on the adhesion of the exposed resist portion to the conductive film, and for example, in the case of indium oxide and/or tin oxide to form a transparent conductive film, a water-soluble type is preferable.

Development may be performed using a development method unique to the resist.

As the etching method, a method of dipping in an etching solution is generally used. However, a spray method in which etching is performed by spraying a cutting/finishing liquid onto the conductive film can also be used for the purpose of accelerating the cutting/finching of the dipping method. In the immersion method, the conductive film is etched at high speed while being immersed, and the etching solution is stirred to accelerate etching.

Methods can also be used.

Any known etching solution can be used, but it is selected as appropriate depending on the type of conductive thin film to be etched. For example, in the case of indium tin oxide, a dilute solution of hydrochloric acid or an acidic aqueous solution of ferric chloride is used. The concentration of these etching solutions may be 1% by weight or more, but preferably 2% by weight considering the etching speed and damage to the substrate.
Preferably it is between 0% and 50% by weight.

In addition, the polymer film used in the present invention includes polystyrene, polymethyl acrylate, polycarbonate,
polyvinyl chloride, acetate, polyether sulfone,
Examples include plastics such as polysulfone, polyethylene, polypropylene, polyamide, polytetrafluoroethylene, and polyester.

(Effects) In the present invention, if heat treatment is performed after exposure, it is effective in easily forming a fine dot matrix display electrode pattern of about 40 μm and having good linearity with no unevenness in the line edges.

Hereinafter, the method of the present invention will be explained in detail with reference to Examples.

Example 1 Polyethylene terephthalate film has a surface resistance of 30
An indium-nuz oxide thin film was deposited so that the resistance was 0Ω/mouth. This film is laminated with a water-soluble photosensitive film resist (Rinuton 3410 manufactured by Debon Co., Ltd.), and a fine photomask for display (30μ, 40P) is laminated onto this film.
, 50IL.

60μ, 70μ, 80μ, 100μ thin line patterns) were used for exposure. After exposure, heat treatment was performed at 40° C. for 2 minutes, and then the non-exposed portions were dissolved and removed with a dilute alkaline aqueous solution. Thereafter, etching was performed with a 25% by volume aqueous hydrochloric acid solution (25°C). After drying, the resist agent was peeled off with dichloroethane, and the laminated resist agent was removed and etching was completed. Moreover, from 30Pm width to 10
A fine etching pattern with a width of 0 μm was formed as a pattern with very good linearity, with no unevenness in the line or edges. The display electrode thus formed could be used as a dot matrix electrode. There was no damage to the exterior of the polyethylene terephthalate film.

Comparative Example 1 In the same manner as in Example 1, an indium-tin oxide thin film having a surface resistance of 300 Ω/hole was deposited on a polyethylene terephthalate film.

This was laminated with the same photosensitive film resist and exposed using a fine display photomask.

After dissolving and removing the non-exposed areas with a dilute alkaline aqueous solution, etching was performed with a 25% by volume aqueous hydrochloric acid solution (25°C).

After drying, the resist agent was removed with dichloroethane. As a result, an etching pattern with a width of 100 to 80 PW was formed, but when it came to a pattern with a width of 70 to 40 μm, unevenness was seen in some places on the line edge, and the line width was ± from the design value.
A deviation of about 10 μm also occurred.

Therefore, it was found that the limit of this method is about 80 μm.

Claims (3)

[Claims] (1) A conductive film characterized in that the conductive film of a polymer film having a conductive film on its surface is masked with a photosensitive resist, exposed to light in a predetermined pattern, heated, developed, and then etched. Pattern formation method (2) A method for forming a pattern of a conductive film according to claim 1, wherein the conductive film is a transparent film made of tin oxide and/or indium oxide. (3) A method for forming a pattern on a conductive film according to claims 1 and 2, wherein the photosensitive resist is water-soluble.