Process using combined capacitively and inductively coupled plasma sources for controlling plasma ion density

摘要

A method of processing a workpiece in the chamber of a plasma reactor includes introducing a process gas into the chamber, capacitively coupling VHF plasma source power into a process region of the chamber that overlies the wafer while inductively coupling RF plasma source power into the process region. A particular plasma ion density level is established by maintaining the total amount of plasma source power inductively and capacitively coupled into the chamber at a level that provides the desired plasma ion density. Chemical species distribution or content in the process region plasma is controlled by adjusting the ratio between the amounts of the capacitively coupled power and the inductively coupled power while continuing to maintain the level of total plasma source power. The method further includes applying independently adjustable LF bias power and HF bias power to the workpiece and adjusting the average value and population distribution of ion energy at the surface of the workpiece by adjusting the proportion between the LF and HF bias powers.