Spatially Uniformizing Of Very High Frequency Plasma For Large Scale Plasma Applications

Spatially uniform and large scale VHF plasma has been required for several kinds of plasma application since VHF plasma enables us to male excellent quality film on surface modification of material for relatively short processing time compared with conventional radio frequency(RF, 13.56MHz). However, VHF plasma is usually generated only on a part of the electrode due to the influence of standing wave since electrode length is almost comparable with wavelength of the VHF power supply and the electrode itself act as a distributed constant circuit. In this research, we have demonstrated the control of VHF plasma generation area by using two methods of the terminal impedance change and the phase modulation. Spatially uniform VHF plasma all over the electrode was successfully obtained by temporally sweeping the plasma generated partially.