Patent ID: 7113256
Filing Date: 2006-09-26
Classification: G03F

Abstract:
1. A lithographic apparatus, comprising: an illumination system configured to provide a beam of radiation; a first support configured to support a patterning device that imparts said beam of radiation with a desired pattern in its cross-section; a second support that includes a substrate holder for holding a substrate; a projection system configured to project said patterned beam of radiation onto a target portion on a surface of said substrate; a servo unit configured to position said substrate holder; a sensor unit configured to determine a distance of at least one location point on the surface of said substrate relative to a reference plane; a memory unit configured to store surface information of said substrate based on respective distances of corresponding location points on said substrate surface; and a calculating unit configured to determine a feed-forward set-point signal based on said stored surface information, wherein said feed-forward set-point signal is forwardly fed to said servo unit in order to position said substrate holder.