Process for forming high copper adhesive strength on dielectric layers structured by a laser comprises applying a dielectric layer on a circuit board, bringing to a specified viscosity, and irradiating the dielectric layer with particles

摘要

Process for forming high copper adhesive strength on dielectric layers structured by a laser comprises (i) applying a dielectric layer (1) which is almost or totally free from solvent on a circuit board; (ii) bringing to a viscosity of 200-2000, preferably 300-600 mPa.s at 80-120 deg C; and (iii) irradiating the dielectric layer with particles (3) having an average grain size of 3-8 mu m soluble in acids, alkalis or solvents so that the surface is almost 60% covered. The particles penetrate the dielectric layer with more than a half of its diameter. Preferred Features: The particles are made of dolomite having an average grain size of 3-8 mu m.