Patent ID: 7727413

Claim:
A method of processing a workpiece in the chamber of a plasma reactor, comprising: introducing a process gas into the chamber; generating plasma ions by simultaneously (a) capacitively coupling VHF plasma source power into a process region of the chamber that overlies the wafer, and (b) inductively coupling RE plasma source power into said process region; controlling plasma ion density by controlling an effective frequency of said VHF source power within a continuous frequency range between an upper frequency limit and a lower frequency limit; wherein coupling VHF source power comprises coupling VHF source power from different generators having different fixed VHF frequencies, and wherein controlling the effective frequency comprises controlling the ratio of power coupled by said different generators; and controlling radial distribution of plasma ion density by adjusting the ratio between of said capacitively coupled RF plasma source power and said inductively coupled RF plasma source power, by changing said inductively coupled and capacitively coupled power levels along lines of constant plasma density.