Adjustable extended electrode for edge uniformity control

A substrate support for a substrate processing chamber, the substrate support comprising:

• a dielectric body configured to support a substrate thereon;
• an edge ring disposed at least partially on the dielectric body, the edge ring having a top surface and a bottom surface;
• an adjustable tuning ring positioned beneath the edge ring, the adjustable tuning ring having a top surface, the top surface of the adjustable tuning ring and the edge ring defining an adjustable gap;
• and
• an actuating mechanism coupled to the adjustable tuning ring, the actuating mechanism configured to alter the adjustable gap.

A processing chamber comprising:

• a dielectric body disposed in the processing chamber and configured to support a substrate thereon;
• an edge ring disposed at least partially on the dielectric body, the edge ring having a top surface and a bottom surface;
• an adjustable tuning ring positioned beneath the edge ring, the adjustable tuning ring having a top surface, the top surface of the adjustable tuning ring and the edge ring defining an adjustable gap;
• and
• an actuating mechanism coupled to the adjustable tuning ring, the actuating mechanism configured to alter the adjustable gap.