A plasma processing reactor is disclosed which incorporates an integral co-axial transmission line structure that effects low loss, very short transmission line coupling of ac power to the plasma chamber and therefore permits the effective use of VHF/UHF frequencies for generating a plasma. The use of VHF/UHF frequencies within the range 50-800 megahertz provides commercially viable processing rates (separate and simultaneous etching and deposition) and substantial reduction in sheath voltages compared to conventional frequencies such as 13.56 MHz. As a result, the probability of damaging electrically sensitive small geometry devices is reduced.