Illumination system for specified wavelengths used especially in EUV lithography includes raster-optical elements selected in number and form to predetermine uniformity of field illumination

摘要

The system produces predetermined light distribution in the exit pupil of the illumination system between light source and secondary light source or at the location of the secondary light sources. Number and/or form of the raster elements illuminated by the source producing the light distribution are so selected that predetermined uniformity of the field lighting in the object or reticular plane is achieved.