摘要 |
An apparatus for preventing edge and backside coating during CVD processing supports a wafer on flexible supports within a purge cavity in a pedestal such that a movable clamp ring deforms the supports, forms a slot with the frontside of the wafer around the periphery of the wafer and by contacting the pedestal isolates the purge cavity from the coating chamber except for the slot. The wafer is heated by a pyrolytic carbon heater in the cavity and purge gas is fed to the purge cavity to flow through the slot and purge coating gas from diffusing into the purge cavity to coat the heater or the edge or backside of the wafer. In an alternative embodiment plural pedestals allow processing of plural wafers in a single cycle, and a vacuum lock and automatic handling devices are provided.
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