Ballistic-Mode Plasma-Based Ion Implantation for Surface-Resistivity Modification of Polyimide Film

Plasma-based ion implantation (PBII) is the well-established technique for material surface modification. In this paper, we described the ballistic-mode PBII process in which repetitive high-voltage pulses are applied to the grid a few centimeters from a polyimide (PI) film target. The high-voltage pulse applied to the grid has the peak values of 30 kV, width of 2.5 μs, rise time of 1.5 μs, and fall time of 0.5 or 40 μs. In this process, ions propagate ballistically from a grid to the PI film and modify the surface resistivity of the PI film. The efficiency of surface-resistivity modification depends on the fall time of the pulse applied to the grid. The ballistic-mode PBII process affects the surface characteristics of PI to a depth of 90 nm.