Wafer clamp ring for use in an ionized physical vapor deposition apparatus

Abstract

Improvements are described for a wafer clamp ring used in an IPVD apparatus to provide cooling for the wafer clamp ring, to protect the wafer clamp ring from ion bombardment, and to prevent damage to the wafer. The wafer clamp ring is placed on a cooling fixture when not required for a deposition process. The fixture is annular in shape and in close thermal contact with a circulating coolant and is thereby cooled below ambient temperature. The cooling line and the cooling fixture are fixed relative to the IPVD device, so that problems associated with flexible cooling lines are avoided. An annular grounded shield may be provided between the plasma and clamp ring to protect the clamp ring against ion bombardment during the deposition process. The wafer clamp ring may have a portion which overhangs the wafer during a deposition process, and which has a ridge portion extending downwards therefrom and tapering to a knife edge. The wafer clamp ring may be fabricated as a split ring with an insulating portion, to prevent heating by induced current in the clamp ring.