Patent ID: 7969550

Claim:
A lithographic apparatus comprising: an illumination system configured to condition a radiation beam; a support constructed to support a patterning device, the patterning device capable of imparting the radiation beam with a pattern in its cross-section to form a patterned radiation beam; a substrate table constructed to hold a substrate; a projection system configured to project the patterned radiation beam onto a target portion of the substrate; a base frame with a metrology frame mounted thereon, wherein the metrology frame is arranged to support the projection system; and a shield device arranged between a source of a pressure wave and an element of the lithographic apparatus sensitive to the pressure wave, wherein the source of the pressure wave comprises a moving object of the lithographic apparatus, and wherein the shield device is arranged to substantially absorb or reflect the pressure wave and the shield device comprises two or more adjacent plates separated by one or more gaps filled with one of an air, a gas, or an acoustic damping material.