Direct Metallization Using Sulfonation of Photosensitive Epoxy Resin for Manufacture of Printed Wiring Board by “Build up Process”

Abstract

A direct metallization method of a photosensitive epoxy resin was proposed in this paper, for manufacturing of printed wiring board by build up process. The sulfo group, as a cation exchange group, was introduced onto the epoxy resin surface through sulfuric acid treatment. The amount of adsorbed copper ions increased with increasing sulfuric acid concentration, dipping time and temperature. It was 2000nmol/cm² for the sample treated with 14M H₂SO₄ solution at 70°C for 30min. The thickness of the copper thin film formed after the reduction process was estimated to be 150nm. The conductivity of the copper thin film was over 0.004 S/_??_ (below 250Ω/_??_) .