OPTICAL SYSTEM OF A MICROLITHOGRAPHIC PROJECTION EXPOSURE APPARATUS, AND MICROLITHOGRAPHIC EXPOSURE METHOD

摘要

The disclosure relates to optical systems of a microlithographic projection exposure apparatus, and to a microlithographic exposure method. According to an aspect of the disclosure, an optical system has a light source, a ray-splitting optical element (110, 310, 410, 510, 706), which splits a light ray incident on this element when the projection exposure apparatus is in operation into a first partial ray (S101, S301, S401, S501, S701) and a second partial ray (S102, S302, S402, S502, S702), with the first and the second partial ray having mutually orthogonal polarization directions, and at least one ray-deflecting optical element (205, 206, 330, 340, 350, 360, 370, 470, 530, 540, 710, 720, 730, 810, 820, 830) for generating a desired polarized illumination setting from the first partial ray (S101, S301, S401, S501, S701) and the second partial ray (S102, S302, S402, S502, S702), wherein the ray-splitting optical element (110, 310, 410, 510, 706) is arranged such that light incident on this ray-splitting optical element when the projection exposure apparatus is in operation has a degree of polarization of less than one.