Positioning system for use in lithographic apparatus

摘要

An H-drive arrangement for the substrate or mask stages of a lithographic apparatus has an X-beam 11 rigidly mounted to Y-sliders 121a, 121b against X and Y translation and rotation about a Z axis (yaw) so as to form a rigid body in the XY plane. Rotation about X and Y axes is permitted in the joint between at least one Y-slider 121a, 121b and X-beam 11. Crash protection may be provided by a yaw rate sensor and/or resilient buffers which contact Y-beams 12a, 12b in the event of out-of-range yaw motions.