Workpiece support structure with four degree of freedom air bearing for high vacuum systems

摘要

A workpiece adjustment assembly is disclosed. The assembly can include a shaft, a spherical bearing, and a wafer support. A spherical housing receives the spherical bearing and allows the bearing to rotate therein. The housing and bearing may form an air bearing. A seal may be formed in the housing to prevent gas from the air bearing and the ambient atmosphere from migrating to a process chamber side of the housing. A set of spherical air pads may be positioned on an ambient side of the bearing to press the bearing against the housing when the process chamber is not under vacuum conditions. The seal can include a set of differentially pumped grooves. The spherical bearing enables the wafer manipulation end, and a wafer attached thereto, to be moved with four degrees of freedom. The arrangement facilitates isocentric scanning of a workpiece. Methods for using the assembly are also disclosed.