A method to determine a rotation of a substrate with respect to the patterning device without using a reference mark on the substrate is presented. At least two structures having corresponding features and present on the substrate, e.g. previously projected patterns, are imaged with a known position...http://www.google.ca/patents/US8064730?utm_source=gb-gplus-sharePatent US8064730 - Device manufacturing method, orientation determination method and lithographic apparatus
