Patent ID: 8518211
Filing Date: 2013-08-27
Classification: H01J,H01L

Abstract:
1. A plasma processing chamber for generating plasma, the plasma processing chamber comprising: a powered electrode configured to receive a wafer or a substrate; a first grounded electrode disposed opposite to said powered electrode, wherein said plasma is configured to be generated between said powered electrode and said first grounded electrode; a second grounded electrode surrounding said first grounded electrode and disposed opposite to said powered electrode; a confinement ring for confining said plasma and surrounding said first and second grounded electrodes and is disposed opposite to said powered electrode, wherein said second grounded electrode is disposed between and surrounded by said confinement ring and said first grounded electrode; an adjustable coupling to ground circuit electrically coupled to said first grounded electrode, said first grounded electrode being electrically coupled to a ground through said adjustable coupling to ground circuit, said adjustable coupling to ground circuit configured to modify an impedance of said first grounded electrode, wherein said adjustable coupling to ground circuit comprises at least one capacitor and a resistor, said capacitor being electrically coupled to said ground through said resistor; and a second coupling to ground circuit electrically coupled to said second grounded electrode, said second grounded electrode being electrically coupled to said ground through said second coupling to ground circuit, said second coupling to ground circuit being external to said second grounded electrode, said second coupling to ground circuit being disposed between said confinement ring and said first grounded electrode; a focus ring, said focus ring surrounding said powered electrode; and a third grounded electrode, said third grounded electrode being disposed below said focus ring such that said focus ring is disposed between said second grounded electrode and said third grounded electrode, said second grounded electrode at least partially overlapping said focus ring and said third grounded electrode, wherein an impedance of said first grounded electrode is different from an impedance of said third grounded electrode.