Patent ID: 6837974

Claim:
A chamber shield for a vacuum processing machine for processing a wafer of a given wafer diameter at a given target-to-substrate spacing from a sputtering target in a vertically-oriented split-plenum that is divided by a vertical index plate that rotates in a vertical plane in the plenum on a horizontal axis to index each of a plurality of wafer holders carried by the plate among a corresponding plurality of vacuum chambers of which a plurality are processing chambers that are each formed in two halves on opposite sides of the index plate by the movement toward each other of a pair of closure members that clamp against a seal ring that is mounted in an opening in the index plate and has one of the wafer holders mounted in its center, the shield comprising: sheet material having a generally circular cross-section and formed into an axially-extending cylindrical sidewall that turns radially inwardly into an annular shoulder that oppositely turns into an at least partially axially-extending section that further turns oppositely back radially inwardly into an annular disc having a central circular opening that is larger in diameter than the given wafer diameter the overall height of the shield is greater than the given target-to-substrate spacing.