Patent ID: 8097120

Claim:
A plasma processing chamber, comprising: a substrate support having a substrate support top surface configured to receive a substrate, the substrate support including an annular edge ring, the annular edge ring having a top surface substantially even with the substrate support top surface; a main process gas feed for supplying a process gas, wherein the main process gas feed is located above the substrate support; and a plurality of tuning gas injection channels defined within the annular edge ring, wherein the plurality of tuning gas injection channels supply a process tuning gas at an outer edge of the substrate support top surface to improve process uniformity at the edge of the substrate, wherein each of the plurality of tuning gas injection channels is pointed toward the center of the substrate oriented at an angle between about 0 degree to about 60 degrees from a vertical axis of the each of the plurality of tuning gas injection channels, the vertical axis being perpendicular to the substrate support top surface, the annular edge ring being proximate to an outer edge of the substrate support and the annular edge ring being coupled to the substrate support, and wherein the plurality of tuning gas injection channels are connected to an edge tuning gas plenum surrounding the substrate support, and wherein the edge tuning gas plenum is connected to a central tuning gas plenum through a plurality of tuning gas supply channels, the central tuning gas plenum being disposed below the substrate and within the substrate support and near-a center of the substrate support, and wherein the plurality of tuning gas supply channels are arranged evenly distributed around a circumference of the central tuning gas plenum in a spoke pattern.