Plasma Surface Modification of Aromatic Liquid Crystal Polymers, and Its Resultant Improvement in Adhesive Strength with Copper Thin Films

Abstract

Surface modification of aromatic LCP surfaces with plasma treatment was carried out to improve the adhesive strength at LCP/Cu interfaces. Plasma treatment to a polymer surface is known to introduce functional groups and to bring about etching action thereon. This study was intended to investigate which or both functional group introduction and etching action contributes to adhesive strength improvement. The effect on the adhesive strength of ordinary plasma treatment and remote plasma treatment was evaluated. Remote plasma treatment is possible to irradiate mainly radicals on LCP surface. The following three subjects were discussed in this study : (1) plasma treatment increases the adhesive strength at LCP/Cu interfaces ; (2) plasma treatment produces oxygen functional groups and nitrogen functional groups and led to etch LCP surfaces, all of which contribute to adhesive strength ; and (3) the oxygen functional groups, nitrogen functional groups, and etching action work simultaneously to enhance adhesive strength by their synergistic effects.