Patent ID: 7542127

Claim:
A lithographic apparatus comprising: a substrate table constructed to hold a substrate, the substrate table being moveable to transfer the substrate between a substrate measuring position and a substrate processing position; a measuring system configured to generate at least one measuring beam and/or field to measure at least one aspect and/or characteristic of the substrate when the substrate table holds the substrate in the substrate measuring position; and a conditioning system configured to supply a conditioning fluid to at least part of a path of the measuring beam and/or at least part of the field of the measuring system to condition the part of the path of the measuring beam and/or the part of the field; wherein the conditioning system comprises a fluid flow control surface that is disposed opposite to, and spaced from, the substrate held by the substrate table when the substrate table is in the substrate measuring position, a surface of the substrate receiving the at least one measuring beam and/or being exposed to the field of the measuring system.