Patent ID: 7695983

Claim:
A method of processing a workpiece in a plasma reactor, comprising: coupling RE power from three RE power sources of three respective frequencies and a magnetic field to plasma in said reactor, by: (a) applying plasma source power of a VHF frequency of at least 60 MHz from a first one of said three RE power sources to a ceiling electrode of said plasma reactor; (b) applying plasma bias power of a first bias frequency greater than an ion transit frequency of said plasma and less than said VHF frequency from a second one of said three RE power sources to a workpiece support electrode of said plasma reactor; (c) applying plasma bias power of a second bias frequency less than said ion transit frequency of said plasma from a third one of said three RE power sources to said workpiece support electrode of said plasma reactor; setting ion energy distribution shape by selecting a ratio between the power levels of said second and third ones of said three RF power sources; and setting ion dissociation and ion density by selecting a ratio between the power level of said first one of said three RF power sources and the strength of said magnetic field.