Patent ID: 7905982

Claim:
A plasma processor for processing a workpiece comprising a non-microwave r.f. source, circuitry including a component of a matching network connecting the r.f. source to an antenna so the antenna is adapted to be driven by power from the r.f. source; the r.f. source, circuitry and antenna being arranged for causing the antenna to supply plasma exciting r.f. electromagnetic energy from the r.f. source to plasma in a vacuum chamber having an interior (a) for containing the plasma, (b) arranged to be responsive to r.f. electromagnetic energy derived by the r.f. source and coupled to the plasma by the antenna and (c) a holder for the workpiece to be processed by the plasma, the chamber including a window, the antenna being outside the window, the window and antenna being arranged so the r.f. electromagnetic energy is coupled to the plasma from the antenna via the window, the antenna including first and second excitation terminals, the circuitry and the component being connected between output terminals of the source and the excitation terminals, the antenna including a transformer having (a) a primary winding having opposite ends arranged to be responsive to the electromagnetic energy derived by the r.f. source by being respectively coupled with the first and second excitation terminals, and (b) a secondary winding reactively coupled with the primary winding without any ohmic connection to the r.f. source, the secondary winding being arranged for applying plasma exciting r.f. electromagnetic energy derived from the r.f. source and coupled to the secondary winding by the primary winding to the plasma via the window; and a capacitor having first and second opposite electrodes respectively connected in series with the secondary winding.