Illumination optics for illuminating structured object such as lithographic mask or wafer, mounted in metrology system, has an energy sensor designed for monitoring the lighting total light dose which hits on the facet mirrors

摘要

The illumination optics (3) has facet mirrors having several facets for reflection of partial beams (13) of illumination light (7), and an energy sensor (12) for detecting the energy of illumination light. The facets represent the coupling facets which are capable of coupling some of the reflected partial beams tilted with respect to the energy sensor. The energy sensor is designed for monitoring the illuminating light total dose which strikes the facet mirrors. The total-reflecting surface of the facet mirrors are distributed in the coupling facets. Independent claims are included for the following: (1) an optical system; (2) a metrology system; and (3) a projection exposure system.