JPH0579197B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention applies to the manufacturing process of printed wiring boards using engineered plastic products for printed wiring (hereinafter referred to as engineering plastics) formed by molding. The present invention relates to a method for forming a photosensitive resist film on a metal coating.

[Prior Art] A conventional printed wiring board in which a metal circuit pattern is attached to the surface of an engineering plastic is manufactured as follows. First, a resist film is formed on the surface of the molded engineering plastic on the side to which the electronic circuit pattern will be attached, and this is exposed to light in a pattern opposite to the desired electronic circuit pattern, and then developed. A pattern identical to the desired electronic circuit is obtained on the surface of the engineering plastic as it is after molding. Next, a palladium metal-containing composition (for example, Kyataposift (trade name, manufactured by Shipley Far East Co., Ltd.) is applied and adhered to the parts of the surface of this engineering plastic where the resist film is not applied, and then electroless copper plating is performed. Printed wiring boards were then manufactured by removing the previous resist film and providing a wiring pattern on the surface of the engineering plastic.Furthermore, in the past, a liquid resist material was used to form a resist film on the surface of the molded engineering plastic. Coating methods such as coating by dipping or brushing, or centrifugal coating have been used.

[Problem that the invention seeks to solve]

Conventionally, as described above, copper was deposited only on the necessary electronic circuit pattern parts on the surface of engineering plastics using electroless copper plating, so it took a long time to deposit electroless copper plating on the surface of engineering plastics. Furthermore, the adhesion between the precipitated copper and the engineering plastic is inferior to the adhesion between the plate and the copper foil in a copper-clad laminate in which copper foil is adhered to the surface of a plate of glass epoxy, etc. There was a problem with it peeling off when shot.

Furthermore, after the electrical circuit pattern is formed, the resist is applied to the surface by dipping or brush coating, so it is difficult to apply the resist uniformly to the required thickness on areas with complex shapes. The problem was that it was difficult to form.

This invention was made to solve the above-mentioned problems, and it improves the adhesion of the copper thin film to the engineering plastic by using a method of forming a copper thin film using a class ion beam device during or after the engineering plastic molding process. In addition, a photosensitive resist film is formed on the surface by electrodeposition (electrophoresis), so it can be coated uniformly without material loss and can completely fill in even the flaws on the surface of the copper foil, improving quality. The aim is to create a method that can be integrated into automated lines without requiring expensive equipment or extra manpower.

[Means for solving problems]

In the method for manufacturing a printed wiring board according to the present invention, an engineering plastic for printed wiring having a thin metal film on its surface is immersed in a water-soluble photosensitive resin housed in an electrolytic bath for electrocoating, and a photosensitive film is deposited by direct current electrolysis. It is something.

[Effect]

In this invention, an engineering plastic for printed wiring with a thin film of metal such as copper on the surface is immersed in a water-soluble photosensitive resin made into an electrodeposition paint stored in an electrolytic bath, and the photosensitive resin is deposited in the form of copper foil by direct current electrolysis. A photoresist film is obtained by drying the copper foil, and there is no loss of material, it is uniform, and it can completely fill and coat even flaws on the surface of the copper foil.

〔Example〕

FIG. 1 is a schematic sectional view showing the implementation status of one embodiment of the present invention, 1 is an electrolytic tank, 2 is an engineering plastic 3 housed therein and having a metal such as copper thin film applied to the surface.
A water-soluble photosensitive resin made into an electrodeposition paint, 4
is a cathode made of stainless steel that is immersed opposite the engineering plastic 3 whose surface is coated with a thin film of copper or the like;
5 is an air blowing pipe for stirring the liquid.

By applying a DC voltage of about 200 V between the engineering plastic 3 whose surface is coated with a metal thin film such as copper, and the cathode 4, the photosensitive resin that was dissolved or dispersed in the liquid 2 and negatively charged is electrodeposited on the surface of the engineering plastic 3 on which a thin film of copper or the like is applied, and as the film thickness increases, the current decreases, and dehydration is performed at the same time as a constant film thickness is obtained. Thereafter, the engineering plastic 3 whose surface is coated with a thin film of metal such as copper is pulled up and dried to obtain a photoresist film.

Fig. 2 is a conceptual side view showing an application example in which the electrolytic cell in the above embodiment is incorporated into an automatic processing line. An engineering plastic 3 with a built-in electrolytic cell 1 and a thin film of metal such as copper applied to the surface.
is transported to a predetermined position at a predetermined time by the automatic transport device 7 and processed.

In the above example, a stainless steel plate was used for the cathode 4, but carbon or other conductive material may also be used. In addition, in the above embodiment, the engineering plastic 3 whose surface was coated with a metal thin film such as copper was used as an anode, but the polarity of the applied voltage was reversed, and the engineering plastic 3 whose surface was coated with a metal thin film such as copper was used as a cathode. Any suitable electrodeposited photopolymer may be used.

〔Effect of the invention〕

As explained above, in this invention, a photoresist film is formed on the surface of an engineering plastic coated with a metal thin film such as copper by electrodeposition coating, so there is no loss of material and automation is extremely easy. Moreover, it also contributes to quality stability and enables effective use of industrial space.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the state of implementation of one embodiment of the present invention, and FIG. 2 is a conceptual side view showing an application example in which the electrolytic cell of the above embodiment is incorporated into an automatic processing line. In the figure, 1 is an electrodeposition coating tank, 2 is a water-soluble photosensitive resin made into an electrodeposition coating, 3 is an engineering plastic whose surface is coated with a metal thin film such as copper, and 6 is a group of tanks for automatic processing.
Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A first step of forming a molded product using an injection molding machine, and a second step of forming a thin copper film for printed wiring using an ion beam device on the surface of the molded product formed in the first step. After this second step, the molded product with the thin copper film formed thereon is transported and immersed in an electrodeposition coating tank built into an automatic treatment tank group, and subjected to the electrodeposition method. Then apply a DC voltage,
a third step of depositing a photosensitive resist film on the surface of the thin film copper of the molded article on which the thin film copper is formed, and a printed wiring board is formed after the third step. Method of manufacturing wiring boards.