Patent ID: 7030961

Claim:
A lithographic projection apparatus comprising: a support structure configured to support a patterning structure, the patterning structure being configured to pattern a beam of radiation according to a desired pattern; a substrate table configured to hold a substrate including an alignment structure having spatially periodically varying optical properties; and an alignment system configured to obtain positional information from light affected by the substrate, to determine a position of the alignment structure relative to the patterning structure based on the positional information, and to control a relative positioning of the patterning structure and the substrate based on the determined position, wherein the alignment system is further configured to obtain position-invariant information from light affected by the substrate and to determine, based on the position-invariant information, a correction to the determined position of an alignment structure, wherein the alignment structure is selected from among (1) the substrate, (2) another substrate that has been subjected to a processing operation in common with the substrate, or (3) a further substrate that has been subjected to a further processing operation according to the same value of a processing parameter used to subject the substrate to the further processing operation.