Patent ID: 7501161

Claim:
A method for use during plasma processing, comprising: placing a substrate horizontally on a substrate holder of a plasma chamber; positioning a non-dielectric cover frame in contact with the substrate, at only a lower surface of the substrate, and disposed so as to contact and cover a portion of the substrate holder, wherein the portion of the substrate holder that is covered is disposed both underneath a portion of the substrate contacted by the cover frame and underneath an area laterally adjacent and outside a perimeter of the substrate; positioning a shadow frame over a portion of the cover frame not covered by the substrate, wherein the shadow frame is distinct from the cover frame, the shadow frame does not contact the substrate, and the shadow frame is tapered down towards the substrate to form a lip at a lateral gap that exists between the shadow frame and the perimeter of the substrate; and performing a plasma process on the substrate while maintaining a neutral electrical potential on the cover frame which is positioned to prevent plasma from contacting the substrate holder which would otherwise be likely to cause arcing.