Patent ID: 7169256
Filing Date: 2007-01-30
Classification: H01J

Abstract:
1. A vacuum plasma processor for processing a workpiece comprising: a vacuum plasma processing chamber including an electrode, the chamber being associated with a reactance, the electrode and reactance being arranged for coupling plasma excitation fields to gas in the chamber, the chamber being arranged for carrying a workpiece, N sources of radio frequency electric power, where N is an integer having a value of at least three, each of the sources being arranged for deriving a different radio frequency, and circuitry for supplying electric power at the N frequencies from the N sources of radio frequency electric power to a region in the chamber via the electrode and reactance, the N frequencies, the power at each of the N frequencies, the electrode, the reactance, and the circuitry being arranged for (a) causing the plasma to be excited to each of the N frequencies and (b) preventing substantial coupling of power to each of said N sources at a frequency other than the frequency associated with the radio frequency of the particular source, the N frequencies and the circuitry being arranged so that at least 26 DB of power attenuation is inserted by the circuitry for preventing substantial coupling of power to each of said N sources at a frequency other than the frequency associated with the radio frequency of the particular source.