Projection illumination system for use with production of e.g. integrated circuit, has interferometer arrangement examining optical components by measuring radiation that strikes on optical surface at specific angle of incidence

摘要

The system has an interferometer arrangement (37) examining optical components (29) by a measuring radiation (65), where the measuring radiation strikes on an optical surface of the optical components at an angle of incidence of 30 degree to a surface normal of the optical surface. A diffractive optical unit is arranged in an optical path of the measuring radiation. A controller controls an actuator (91) of the interferometer arrangement in dependence of an analysis of radiation intensities that are detected by a radiation detector.