Patent ID: 8900398

Claim:
An arrangement for performing pressure control within a processing chamber of a plasma processing system during processing of a substrate, said processing chamber including a chamber wall, comprising: a peripheral ring configured at least for surrounding a confined chamber volume, said peripheral ring including a peripheral ring vertical structure that is disposed inward of said chamber wall such that said confined chamber volume does not extend to said chamber wall, wherein said confined chamber volume is capable of sustaining a plasma for etching said substrate during substrate processing, said peripheral ring including a first plurality of slots, wherein said first plurality of slots is configured at least for exhausting processed byproduct gas from said confined chamber volume during said substrate processing; and a conductive control ring, wherein said conductive control ring is positioned next to said peripheral ring, wherein said peripheral ring is nested inside said conductive control ring such that said conductive control ring surrounds said peripheral ring, said conductive control ring includes a second plurality of slots, wherein each of said peripheral ring and said conductive ring comprises an upper portion, a side portion, and a lower portion wherein at least one of the upper portion, the side portion, and the lower portion of said peripheral ring comprises a first slot of said first plurality of slots and said conductive control ring comprises a second slot of said second plurality of slots, wherein said pressure control is achieved by moving said conductive control ring relative to said peripheral ring such that said first slot of said first plurality of slots of said peripheral ring and said second slot of said second plurality of slots of said conductive control ring are offset with respect to one another in a range of zero offset to full offset.