ALIGNER FOR ARRAGING MASK AND SUBSTRATE MUTUALLY

摘要

An arrangement is described for aligning a mask (1) and a substrate (3) relative to each other by means of grating marks (M1, M2; P1, P2) in the mask and in the substrate. A diaphragm (32) is arranged in the path of the alignment beam (b') behind the mask grating (M2) and transmits only specific diffraction orders of the gratings (P2, M2), so that the alignment signal (SA) contains less undesired components and becomes more accurate.