An alignment system for a lithographic apparatus has a source of alignment radiation; a detection system that has a first detector channel and a second detector channel; and a position determining unit in communication with the detection system. The position determining unit is constructed to process...http://www.google.es/patents/US8139217?utm_source=gb-gplus-sharePatente US8139217 - Alignment systems and methods for lithographic systems
Alignment systems and methods for lithographic systems
