Patent ID: 7695633
Filing Date: 2010-04-13
Classification: H01J,H01L

Abstract:
1. A method of processing a workpiece in a plasma reactor, comprising: coupling RF power from at least three RF power source of three respective frequencies to plasma in said reactor; setting ion energy distribution shape by selecting a ratio between the power levels of a first pair of said at least three RF power sources; and setting ion dissociation and ion density by selecting a ratio between the power levels of a second pair of said at least three RF power sources; wherein said power sources comprise four RF power sources, and wherein said first pair corresponds to an HF frequency and a lower frequency in a frequency range up to 2 MHz, and said second pair corresponds to a VHF frequency and another frequency; wherein said first pair comprises a first frequency that is less than an ion transit frequency and a second frequency that is greater than said ion transit frequency; wherein the step of setting said ion energy distribution comprises adjusting the energy difference between a pair of peaks of the ion energy distribution.