IMAGING OPTICAL SYSTEM AND PROJECTION EXPOSURE INSTALLATION FOR MICROLITHOGRAPHY INCLUDING SAME

摘要

An imaging optical system has a plurality of mirrors which image an object field in an object plane into an image field in an image plane. The imaging optical system has a pupil obscuration. The last mirror in the beam path of the imaging light between the object field and the image field has a through-opening for the passage of the imaging light. A penultimate mirror of the imaging optical system in the beam path of the imaging light between the object field and the image field has no through-opening for the passage of the imaging light. The imaging optical system has precisely eight mirrors. The result is an imaging optical system which exhibits a favorable combination of small imaging errors, manageable production and good throughput.