Plasma-based ion process in the dual-plasma configuration

A novel plasma-based ion process characterized by the dual plasma configuration, which we call the dual-plasma immersion ion process and which has been developed for the surface treatment of electrically insulating materials, is reported. In this process, the plasma is divided into two parts by a negatively biased grid: the target plasma and the driver plasma. The workpiece to be treated is set in the target plasma. If a dc or pulsed positive bias is applied to the driver plasma against the target plasma at ground potential, an ion sheath develops on the grid and a potential difference happens across the ion sheath. When we see the dual-plasma process from the workpiece, it gets the impact of ions from the driver plasma while being immersed in the target plasma at ground potential. Thus, this new process enables treatment of insulating materials because the surface charge induced by the ion impact is completely reduced by the inflow of electrons from the target plasma.In the present paper, the basic idea of the dual-plasma immersion ion process and results of the proof-of-principle experiment are presented.