Patent ID: 7408616

Claim:
An exposure method for exposing a substrate which is arranged in the area of an image plane of a projection objective of a projection exposure system by at least one image of a pattern of a mask which is arranged in the area of an object plane of the projection objective, comprising: illuminating the pattern with illumination radiation from an illumination system for production of radiation which is changed by the pattern; passing the radiation which has been changed by the pattern through the projection objective in order to produce output radiation directed at the substrate and having an output polarization state; measuring the output polarization state with an aid of at least one polarization measurement device for production of an actual signal which represents the current actual output polarization state; variably adjusting the output polarization state with the aid of at least one polarization manipulation device as a function of an adjustment signal derived from the actual signal in order to make the output polarization state approach a nominal output polarization state which is intended for the exposure.