Euv microlithography illumination optical system and euv attenuator for same

Abstract

An illumination optical system for EUV microlithography is used to direct an illumination light beam from a radiation source to an object field. At least one EUV mirror has a reflective face with a nonplanar mirror topography for forming the illumination light beam. The EUV mirror has at least one EUV attenuator arranged in front of it. The attenuator face which faces the reflective face of the EUV mirror has an attenuator topography which is designed to complement the mirror topography such that at least sections of the attenuator face are arranged at a constant interval from the reflective face. The result is an illumination optical system in which it is possible to correct unwanted variations in illumination parameters, for example an illumination intensity distribution or an illumination angle distribution, over the object field with as few unwanted radiation losses as possible.

Dependencies are inferred from the claim text.