Method and Lithography Device with a Mask Reflecting Light

摘要

A method and lithography device addressing the problem in projection optics of pupil apodization which leads to imaging defects. As here proposed, the illumination system is configured to illuminate the mask inhomogeneously. As a result, inhomogeneities in reflectivity caused by the mask itself are at least partly counteracted. This compensation not only makes the apodization over the pupil become more symmetric but also makes the intensity variation smaller overall.