Rf plasma source for material processing

Abstract

The present invention provides a plasma source that maintains a low coil voltage in the vicinity of the plasma tube, thereby reducing the capacitive coupling between the coil and the plasma and significantly reducing the erosion from the internal surfaces of the plasma tube. The plasma source generally comprises a coil having a first coil segment and a second coil segment, an RF power source connected to the coil and an enclosure disposed between the first coil segment and the second coil segment. The invention also provides a method for generating a plasma, comprising: disposing an enclosure between a first coil segment and a second coil segment; introducing a gas into the enclosure; and supplying an RF power to the coil segments to excite the gas into a plasma state. The invention provides a variety of coil operations, including symmetrical coil configuration, asymmetrical coil configuration with the matching networks adjusted to provide a low voltage near the plasma chamber, self-resonant configuration, grounded coil center configuration having coil segments driven in parallel and physically grounded near the plasma chamber, and pairs configurations having a plurality of coil segment pairs driven in series or parallel.