Patent ID: 8760615

Claim:
A lithographic apparatus, comprising: a support constructed to hold a patterning device, the patterning device being capable of imparting a 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; an encoder sensor system configured to measure a position of the substrate table relative to a reference structure, the encoder sensor system comprising an encoder sensor head and an encoder sensor target; and a lens conditioner configured to condition a downstream lens of the projection system, wherein the encoder sensor target is positioned within a recess of the reference structure, wherein the recess is formed between a surrounding structure coupled to a surface of the reference structure, the surrounding structure located between the support and the lens conditioner and surrounding at least part of the encoder sensor target, the lens conditioner further configured to provide a side of the recess, and wherein the encoder sensor target comprises a material having a substantially zero thermal expansion coefficient, or a high thermal conductivity coefficient, or both a substantially zero thermal expansion coefficient and a high thermal conductivity coefficient.