ILLUMINATION SYSTEM OF A MICROLITHOGRAPHIC PROJECTION EXPOSURE APPARATUS

摘要

An illumination system of a microlithographic projection exposure apparatus can include at least one transmission filter which has a different transmittance at least at two positions and which is arranged between a pupil plane and a field plane. The transmittance distribution can be determined such that it has field dependent correcting effects on the ellipticity. In some embodiments the telecentricity and/or the irradiance uniformity is not affected by this correction.