Research on etching blind holes and desmear with plasma

Plasma has a special advantage in cleaning micro blind holes due to simple process, easily operate and non-pollution. In this paper, different etching rates of materials include epoxy, polyimide(PI) and acrylic aid were obtained by cleaning blind holes with plasma in the same condition. The relationship between plasma parameters and etching depths of PI were discussed through orthogonal experimental design (OED). The effects of etching blind holes were investigated through metallographic cross section. Blind holes in a double-side flexible printed circuit(FPC) with PI materials were successfully obtained by plasma etching process.