Adjusting device for an alignment apparatus

摘要

The structure of an alignment apparatus is as follows: The illuminating areas of the two laser beams for the use of alignment, which are irradiated onto a diffraction grating on a substrate and a diffraction grating mark on a fiducial member, are relatively driven by a field diaphragm and a diaphragm member. A photoelectric detector receives the interference light generated from a first portion in the area on the above-mentioned diffraction mark where the two laser beams intersect following the above-mentioned relative driving, and receives the interference light generated from a second portion in the aforesaid area. A main control system calculates the intersecting angles or rotational error of the two laser beams on the basis of the phase difference of the detection signals from the aforesaid photoelectric detector. The intersecting angles or rotational error is corrected by allowing the parallel flat glasses, which are arranged on the light path, to be slanted.