Coherence mask for measuring wavefront of optical system of extreme UV projection exposure system for microlithography, has set of diffuser structures arranged in two different orientations on mask, respectively

摘要

The mask (24) has a set of diffuser structures for widening incoming electromagnetic radiations (20) to illuminate an optical system (12), where the diffuser structures are arranged in two different orientations on the mask, respectively. The diffuser structures are integrated into measuring samples and are identically formed, where the mask measures the wavefront of the optical system by the electromagnetic radiations in extreme UV (EUV) and/or high frequency wavelength range. Independent claims are also included for the following: (1) a projection exposure system for microlithography (2) a method for measuring wavefront of an optical system (3) a device for measuring wavefront of an optical system.