Optical method and optical measuring device for measuring the angular position of facets of at least one facet mirror for EUV applications

摘要

The method involves detecting the measurement light which is reflected from facets (16,18) of facet mirrors (12,14). The detected measurement light is evaluated for the acquisition of actual angular positions of the facets. The angular positions of the facets are adjusted in a deviation of the actual angular positions. The actual angular positions of the facets are detected in a predetermined spectrum of angular positions with respect to a reference axis. An independent claim is included for an optical measurement device for measuring angular position of facet of facet mirror.