JPS61226996A - Manufacture of printed wiring board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of manufacturing a printed wiring board in which carbon is printed and coated on electrodes and contact circuits.

(Prior technology) Electrodes and contacts provided on printed wiring boards were originally constructed by plating precious metals such as gold on the surface of copper foil, but recently carbon materials have become cheaper than gold plating. Since they have the advantage of being able to be formed by printing and coating, those with a structure in which a carbon layer is formed have come to be widely used.

By the way, such printed wiring boards are manufactured by forming a predetermined circuit using copper foil or the like on an insulating substrate, then printing and applying carbon ink to the electrodes and contacts, and then printing a solder resist between the carbon layers. .

(Problems to be Solved by the Invention) However, carbon has the drawback that it bleeds easily, and short-circuiting is likely to occur if the electrode spacing or contact spacing is narrow.Also, in order to improve these drawbacks, carbon's viscosity and It is necessary to strictly select the temperature, mesh of the printing plate, etc.
The drawback was that it was difficult to manage.

An object of the present invention is to provide a method for manufacturing a printed wiring board that can improve the above-mentioned drawbacks, facilitate carbon printing, and prevent short circuit defects due to carbon bleeding.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a printed circuit characterized in that after a predetermined circuit is formed on an insulating substrate, a carbon layer is formed on a part of the circuit. In the method for manufacturing a wiring board, the steps of forming a solder resist pattern by leaving gaps between the circuits that will become electrodes or contacts after forming the circuit, and forming a carbon layer on the surface of the circuit after the step are performed. The present invention provides a method for manufacturing a printed wiring board characterized by:

(Function) According to the present invention, since a solder resist layer is formed between the circuits after the circuit is formed and before the carbon layer is formed,
Even if the carbon ink bleeds or spreads, the solder resist layer acts as a barrier and prevents adjacent carbon layers from coming into contact with each other.

<Example> Embodiments of the present invention will be described below based on the drawings.

First, as shown in FIG. 1, a copper foil circuit 2 is formed on an insulating substrate 1 such as a paper phenolic resin laminate or a paper epoxy resin laminate by a full additive method, an etching method, or the like.

Next, as shown in FIG. 2, a solder resist layer 4 is formed by printing a solder resist, leaving gaps 3 on both sides of the circuit 2, especially the circuits constituting electrodes and contacts.

After forming the solder resist layer 4, as shown in FIG. 3, carbon ink is applied and printed on the circuit 21 to form a carbon layer 5.

That is, according to the above embodiment, the solder resist 1- is printed between the circuits 21 before printing and applying the carbon ink, and the solder resist layer 4 acts as a barrier to prevent short circuit failures due to bleeding of the carbon ink. .

<Effects of the Invention> As described above, according to the present invention, since a carbon layer is formed after forming a single layer of solder resist 1 between electrodes and contacts, short circuit failures due to bleeding of carbon ink can be prevented. Furthermore, a method for manufacturing a printed wiring board in which carbon ink and the like can be easily managed can be obtained.

[Brief explanation of the drawing]

Figures 1 to 3 show the manufacturing process of the present invention; Figure 1 is a cross-sectional view of a circuit formed on an insulating substrate, Figure 2 is a cross-sectional view of a solder resist layer formed, and Figure 3 is a cross-sectional view of a circuit formed on an insulating substrate. shows a cross-sectional view of a state in which a carbon layer is formed. 1... Insulating substrate, 2.2'... Circuit, 3...
void, 4... solder resist 1 layer, 5... carbon layer.

Claims (1)

[Claims] (1) After forming a predetermined circuit on an insulating substrate, one of the circuits is
A method for manufacturing a printed wiring board characterized by forming a carbon layer on a portion of the printed wiring board, which includes a step of forming a solder resist layer by leaving a gap between the circuits that will become electrodes or contacts after the circuit is formed, and a step of forming a solder resist layer after forming a carbon layer on the circuit. 1. A method for producing a printed wiring board, comprising the step of forming a carbon layer on the surface.