CRYOPUMP WITH DIFFERENTIAL PUMPING CAPABILITY

摘要

A cryopump is capable of pumping a process chamber at a process pressure and differentially pumping a second chamber such as an RGA independently at a substantially lower pressure. A member extends through the cryopump housing into a low pressure region disposed within the second stage array. The member comprises a port for accessing the low pressure region, thus providing an independent differential pumping source. No physical seal is required between the member and the main cryopump volume to maintain the pressure differential.