| abstract |
A photo sensitive resin composition containing a polysilane having an average molecular weight of more than 10,000 soluble in an organic solvent, photo radical generating agent, oxidant, silicone oil, an organic solvent, is applied to a printed circuit board to from a solder resist film is selectively exposed and developed, and solder is applied to expose the wiring port. The marking area of the solder resist film is then exposed, and the exposed area is impregnated with a color dye and printed with a desired mark. |