Apparatus and method for aligning and controlling edge deposition on a substrate

Abstract

An alignment mechanism for aligning a substrate on a support member in a process chamber includes a set of guide pins extending from the upper surface of the support member equally spaced about the periphery thereof and spaced to receive a substrate therebetween and align a shadow ring thereover. The inner surfaces of the guide pins are slanted outwardly to form an inverted funnel for receiving and aligning the substrate on the support member. An annular gas groove in the upper surface of the support member provides communication for a supply of purge gas and directs the gas about the peripheral edge of the substrate. The guide pins which extend partially over the gas groove include slots therein that provide fluid communication through the guide pins from the gas groove to the peripheral edge of the substrate. The guide pins also mate with alignment bores formed in the shadow ring so that, as the support member moves into the processing position, the inner surfaces of the guide pins abut abutment surfaces in the alignment bores and align the shadow ring on the support member and over the substrate. A hanger member supports and aligns the shadow ring between processing of each substrate.