This Ground Quartz Cover Ring is a high purity synthetic quartz plasma etching quartz ring built for 12 inch CCP dry plasma etching equipment. Positioned at the wafer perimeter, the ring confines the plasma sheath, shields the chamber edge and protects the wafer from edge erosion during long, high power etch steps. Because it is machined from synthetic fused quartz rather than natural quartz, the ring offers an exceptionally low level of metallic and hydroxyl contamination,