Photodefined metal pattern formation and its electromagnetic interference shielding effect

摘要

This paper proposes a electromagnetic interference (EMI) shielding effect of Cu mesh patterns which were formed by a novel, low-cost, photodefined metal pattern using a bilayer thin film of amorphous titanium dioxide (TiO_2) and hole-scavenger-containing poly(vinyl alcohol) (PVA). Via UV-irradiation through a photomask on the bilayer film, the photodefined image of photoelectrons can be easily produced, resulting in selective palladium (Pd) catalyst deposition by reduction. In the bilayer thin film, the hole-scavenger-containing PVA layer scavenge the holes in the valence band of UV-irradiated TiO_2 thin film, this retarding the recombination of the photoexcited electron-hole pairs for a few minutes. These long-surviving photoelectrons in the bilayer structure can reduce the Pd ions on only the photodefined region. Successive Ni electroless plating on Pd catalysts and Cu electroplating on an electroless plated pattern are possible. The electromagnetic interference shielding effects of selective nickel and copper mesh patterns were investigated.