Lam Research Corporation
Conical wafer centering and holding device for semiconductor processing

Abstract:

A semiconductor system includes a chamber, a pedestal disposed in the chamber, and a focus ring that surrounds the pedestal. The pedestal has a center region for supporting a central region of a substrate, e.g., a wafer. The focus ring is configured to surround the center region of the pedestal. The focus ring has an annular support region that extends between an inner portion of the focus ring and an outer portion of the focus ring. The annular support region, which is disposed at an angle relative to a horizontal line, provides a knife-edge contact for the substrate when present over the center region of the pedestal and the annular support region of the focus ring. The knife-edge contact between the edge of the substrate and the annular support region of the focus ring disables chemical access to the substrate backside and thereby reduces unwanted backside deposition.