JPS592196B2 - Photo resist pattern formation method on thick film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of forming photoresist patterns on thick films by screen printing, and the so-called thick film technology by screen printing is superior to thin film technology which requires expensive and difficult-to-handle equipment. As the manufacturing equipment is simple and easy to handle, it is suitable for manufacturing circuit parts and devices for various electronic devices.
・Widely used to create wiring patterns for various circuits including hybrids and ICs.

However, the minimum pattern width of the circuit manufactured using this technology is 1
The limit is about 0.00 to 200 microns, so to generate a circuit with a narrower pattern width, a screen-printed thick film paste is applied and dried, then a photoresist is applied to the surface, and a photoresist is applied through a pattern mask. A method of applying the so-called photoresist technology, which involves exposure and development, was considered.

By this method, the width of the circuit pattern produced was reduced to about 30 to 40 microns for several products at once.

However, it is extremely difficult to reduce the amount further than this, and according to the research of the present inventor, the reason for this is that the thick film surface formed by screen printing is not smooth at first glance, but has irregularities of 2 to 5 microns. It turned out that it was because of something.

As long as screen printing is used, the formation of this unevenness cannot be avoided due to the mesh of the screen used, and therefore the formation of unevenness on the surface of the photoresist applied to the surface after drying is also unavoidable. Even if a pattern mask was brought into close contact with the photoresist film and exposed, a so-called well-cut circuit pattern could not be obtained because the degree of contact between the mask and the photoresist film was partially different.

The present invention seeks to eliminate this drawback and to provide a method for further reducing the circuit pattern width, the purpose of which is to provide a method for further reducing the circuit pattern width by brushing the surface of the thick film applied by screen printing after drying. This can be achieved by reducing the degree of surface unevenness and smoothing the surface.

For brushing, if you are using commercially available sandpaper, use a thin piece of 1500 grit or higher, and rub it over the thick film for 2 to 2 minutes.
By brushing three times, the degree of unevenness on the thick film can be halved.

Also, instead of the sand paper mentioned above, a brushing sheet such as Scotchi Bright manufactured by Sumitomo 3M, or a commercially available cleaning flash (a flash made of a bundle of glass fibers with a diameter of 20 to 25 microns) may be used. Similar results were obtained. An embodiment of the present invention in which a fine wiring pattern is formed on a glass substrate will be described below.

A commercially available conductive paste (a mixture of gold, silver, gold/platinum, etc. noble metal powder and glass frit dispersed in an organic binder) is made by screen printing on a glass substrate.
is applied uniformly to a thickness of 10-odd microns, dried at 70°C to 150°C for 15 to 30 minutes, and the surface is brushed several times with the cleaning brush described above.

This brushing reduces the degree of surface unevenness of the thick film to 1.
Reduced to 5-3 microns.

Next, a PVA-based photoresist is applied to the surface to a thickness of several microns using a known technique, a pattern mask is adhered to the surface, exposed, developed, etched with chlorocene, and completed by baking.

Claims (1)

[Claims] 1. A photoresist pattern on a thick film by screen printing, which is characterized by applying a thick film paste onto a substrate, drying it, smoothing the surface by brushing, and applying a photoresist thereon. Formation method.