Patent ID: 7151591

Claim:
A lithographic apparatus comprising: an illumination system configured to condition a radiation beam; a pattern support configured 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; a substrate table configured to hold a substrate; a projection system configured to project the patterned radiation beam onto a target portion of the substrate, an alignment system configured to align two devices with respect to each other, the alignment system comprising a proximity switch, a control system operatively connected to the proximity switch and configured to receive a detection state of said proximity switch, and at least one actuator operatively connected to said control system and configured to move a first of said two devices relative to a second of said two devices, wherein the alignment system is configured to determine a position of said first device relative to said second of said two devices in at least two directions with said proximity switch.