Control device for spectral filter of extreme UV projection exposure system, has condenser lenses forming light of light source into monitoring light beam to condition filter transmitted light and/or reflected light for detector

摘要

The device has detectors (59, 61) for detecting light (52) of a light source (51), where the light source and the detectors are arranged with respect to a filter (11) such that the filter partially prevents the light of the light source from reaching the detector or reflects the light into the detector. Condenser lenses (53, 57) form the light of the light source into a monitoring light beam (54), which is directed toward the filter and/or conditions a filter transmitted light (56) and/or a reflected light (55) for the detector. Independent claims are also included for the following: (1) a projection exposure system (2) a method for monitoring a filter of a projection exposure system.