Patent ID: 8869741

Claim:
A plasma processing system having a plasma processing chamber configured for processing a substrate, comprising: at least an upper electrode and a lower electrode for processing said substrate, said substrate being disposed on said lower electrode during plasma processing, where said upper electrode and said substrate forms a first gap, wherein said upper electrode is grounded and wherein said lower electrode is powered; an upper electrode peripheral extension (UE-PE), said UE-PE is mechanically coupled to a periphery of said upper electrode, where said UE-PE is also grounded and configured to be non-coplanar with said upper electrode; and a cover ring formed of quartz that surrounds said lower electrode, wherein a lower surface of said UE-PE and an upper surface of said cover ring forms a second gap, wherein said second gap is smaller than said first gap and wherein one of said upper electrode, along with said UE-PE, and said lower electrode, along with said cover ring, is movable in a direction perpendicular to a planar surface of said lower electrode to form at least a first operating mode and a second operating mode whereby said second gap in said second operating mode is larger than said second gap in said first operating mode, said first operating mode characterized by having plasma in said first gap but not in said second gap and by a first RF coupling area ratio of grounded electrode area to powered electrode area, said second operating mode characterized by having plasma in said first gap and also plasma in said second gap and by a second RF coupling area ratio of grounded electrode area to powered electrode area that is larger than said first RF coupling area ratio.