METHOD FOR ALIGNING A MIRROR OF A MICROLITHOGRAPHIC PROJECTION EXPOSURE APPARATUS

摘要

The invention relates to a method for aligning a mirror of a microlithographic projection exposure apparatus. In accordance with one aspect of the invention, a method according to the invention comprises the following steps: recording a first partial interferogram between a wave reflected at a first mirror segment (101) and a reference wave reflected at a reference surface (110, 310, 510), recording a second partial interferogram between a wave reflected at a second mirror segment (102) and a reference wave reflected at the reference surface (110, 310, 510), determining a phase offset between the first partial interferogram and the second partial interferogram, and aligning the first mirror segment (101) and the second mirror segment (102) with respect to one another on the basis of the phase offset determined in such a way that the distance between the relevant mirror segments (101, 102) in the direction of the respective surface normals and a fictitious, predefined desired surface at every point on the mirror segments is less than λ/10, wherein λ denotes the operating wavelength.