Patent ID: 7256866

Claim:
A lithographic apparatus comprising: (a) an illumination system configured to condition a radiation beam; (b) a pattern support constructed to support a patterning device, the patterning device being capable of imparting the radiation beam with a pattern in its cross-section to form a patterned radiation beam, the pattern support being moveably supported by a first actuator assembly, the first actuator assembly comprising a long stroke actuator configured to position the patterning device with respect to a fixed reference point; (c) a substrate table constructed to hold a substrate, the substrate table being moveably supported by a second actuator assembly, the second actuator assembly comprising a long stroke actuator and a short stroke actuator configured to position the substrate with respect to the fixed reference point; (d) a projection system configured to project the patterned radiation beam onto a target portion of the substrate; and (e) a control system comprising (i) a determination system configured to determine an actual position of said patterning device, and (ii) control circuitry operatively connected to said determination system, said first actuator assembly, and said second actuator assembly, the control circuitry being configured to: position said patterning device to obtain a desired pattern position; determine a pattern positioning error by comparing said desired pattern position and said actual position of said patterning device; determine a desired substrate position to substantially compensate said pattern positioning error; and position said substrate at said desired substrate position.