Perforated plasma confinement ring in plasma reactors

A perforated plasma confinement ring for containing a plasma inside a process chamber of a plasma reactor during processing of a substrate, the plasma reactor including a bottom electrode and a side wall formed from either an electrically insulating material or a material that is electrically floating, the perforated plasma confinement ring comprising:

• a conductive ring having an inner periphery dimensioned to surround said bottom electrode in said plasma processing reactor such that a portion of the inner periphery is positioned between planes that define the top and bottom of said bottom electrode when said conductive ring is surrounding said bottom electrode, said conductive ring being configured for placement in its entirety at or below a top surface of said substrate when said substrate is disposed inside said process chamber for said processing, said conductive ring being formed from an electrical conductor that is substantially resistant to etching by said plasma present within said chamber during said processing and electrically grounded during said processing so as to increase ion energy in said plasma by removing electrons from said plasma through said conductive ring, said conductive ring having therein a plurality of perforations, said plurality of perforations being dimensioned to permit by-product gases from said processing to pass through while substantially confining said plasma to the upstream side of said conductive ring.