Patent ID: 9396908
Filing Date: 2016-07-19
CPC Classification: H01J,H05B

Claim Text:
1. A system comprising: a top electrode and a bottom electrode for generating an electric field; one or more upper insulating rings surrounding a portion of the top electrode; a lower insulating ring surrounding a portion of the bottom electrode; an upper electrode extension surrounding a portion of the one or more upper insulating rings; a lower electrode extension surrounding a portion of the lower insulating ring, wherein at least a portion of a plasma center region is formed between the top electrode and the bottom electrode, wherein at least a portion of a plasma edge region is formed between the upper electrode extension, the lower electrode extension, and a C-shroud; and a control circuit having an inductor, the control circuit being connected to the upper electrode extension for filtering a first radio frequency signal provided to the upper electrode extension, wherein the top electrode is coupled with ground and the upper electrode extension is coupled with a variable capacitor and the inductor, wherein the variable capacitor is coupled in parallel with the inductor, and a controller that is coupled with the control circuit, wherein the controller is configured to adjust a capacitance of the variable capacitor to provide an impedance to the upper electrode extension such that a potential of a top plasma sheath within the plasma edge region is in phase with a potential of a bottom plasma sheath within the plasma edge region.