Illumination optics for extreme UV projection lithography to guide illuminating light to lighting field, has channel guiding light sub beams, where difference between run times of sub beams is greater than coherence duration of light

摘要

The optics (4) has an illuminating channel guiding sub beams of an illuminating light (16). Run time differences between the light sub beams are produced depending on differences in path lengths of optical paths of the illumination channel. A difference between run times of the light sub beams is greater than a coherence duration of the illuminating light. The difference between running times of the light sub beams is measured between a location i.e. intermediate focus plane (18) in the optical path of illuminating light before division into the light sub beams and a lighting field (5). Independent claims are also included for the following: (1) a projection exposure system (2) a method for performing a projection exposure.