Arrangement for determining the spectral reflectivity of a measurement object

Abstract

In an arrangement for determining the spectral reflectivity of a measurement object, the object of the invention is to provide a simpler and more compact measuring arrangement, to eliminate the removal of elements from the beam path for detecting the reference beam, which was formally necessary, and to avoid complex translational and rotational movements. Different beam areas proceeding from the radiation source serve as measurement beam and reference beam which are directed simultaneously to different spectrally dispersing areas of at least one dispersive element and to different receiver areas of at least one receiver in a spectrograph. Preferred measurement objects are surfaces which reflect in a spectrally-dependent manner for radiation in the extreme ultraviolet range (EUV), but application of the arrangement is not limited to this spectral region.

Dependencies are inferred from the claim text.