IMAGING OPTICAL SYSTEM FOR A METROLOGY SYSTEM FOR ANALYZING A LITHOGRAPHY MASK

摘要

The invention relates to an imaging optical system (40) which is used to analyze a lithography mask within a metrology system. Said lithography mask can be arranged in an object field (3) of the imaging optical system. Said object field (3) is defined by two object field coordinates (x, y) which are mutually perpendicular. The imaging optical system (40) comprises an aperture diaphragm (42), the aspect ratio thereof in the direction of both object field coordinates is different by 1. As a result, an imaging optical system which can be used to analyze lithography masks which are designed for projection lithography by means of an anamorphotic projection optical system is obtained.