Stacked six degree-of-freedom table

Abstract

A table with six degrees of freedom, such as a wafer table for a lithography system, has an upper table stacked on top of a lower table. Each of these two stacked tables has three degrees of freedom and is provided with actuators for controlling its motions in these three degrees of freedom. The vertical motion, the pitching and the rolling of the lower table may be controlled by actuators that may be voice coil motors. The upper table is supported on the flat top surface of the lower table so as to be slidable laterally, or two dimensionally. This two dimensional motion of the upper table and its yaw may be controlled by another set of actuators which may be smaller voice coil motors. A wafer holder supporting a workpiece such as a wafer for the lithography system may be secured onto the upper table by a vacuum suction mechanism.

Dependencies are inferred from the claim text.