ILLUMINATION SYSTEM FOR A MICROLITHOGRAPHY PROJECTION EXPOSURE INSTALLATION

摘要

The invention relates to an illumination system for a microlithography projection exposure installation for illuminating an illumination field (7) with the light from an associated light source (10). Said system comprises at least one polarisation compensator (11) which is arranged in a pupil plane (23) of the illumination system and can be used to at least partially compensate a polarisation modification introduced by elements (5) which modify the polarisation according to the angle. Said polarisation compensator (11) comprises polarisation modification means for modifying the polarisation according to the location, said means being embodied as double-refractive elements or elements comprising a double-refractive structure. Such a polarisation compensation can improve the transmission characteristics of the microlithography projection exposure installation, especially when using a downstream projection objective with a physical beam splitter.