Patent ID: 7927424

Claim:
A clamp ring for securing a substrate comprising: a body, the body including one or more substrate contacting surfaces projecting from the body each contacting the substrate at a peripheral edge of the substrate when the clamp ring is securing the substrate; and an edge exclusion lip projecting from the body inwardly from the substrate contacting surfaces, the edge exclusion lip having a first bottom surface extending a first width from the body toward a terminal edge of the edge exclusion lip furthest from the body and a first height from a plane including the substrate contacting surfaces, and a second bottom surface extending a second width from the terminal edge toward the body and a first height plus a second height from the plane including the substrate contacting surfaces, wherein, when the clamp ring is securing the substrate, the first bottom surface is substantially constantly spaced from the substrate across the first width and the second bottom surface is variably spaced from the substrate across the second width, and wherein a surface joining the first bottom surface and the second bottom surface is perpendicular to the first bottom surface.