Patent ID: 8635971
Filing Date: 2014-01-28
Classification: H01J

Abstract:
1. A plasma processing chamber capable of tuning the uniformity of a plasma by affecting a local density of the plasma; comprising, at least one electromagnetic radiation source and an edge ring having a plasma exposed surface; wherein radiation of the radiation source is directed onto the plasma exposed surface and the edge ring generates photoelectrons emitting from the plasma exposed surface into the plasma; wherein the local density of the plasma is affected by acceleration of the photoelectrons into the plasma with sufficient energy to cause local ionization of the plasma; wherein the electromagnetic radiation compensates for existing non-uniformities in the plasma density or in the plasma process; wherein the at least one electromagnetic radiation source comprises a series of evenly spaced radiation sources arranged to provide uniform illumination around the edge ring embedded in the inner or outer electrode part of a multi-piece showerhead electrode assembly.