Method for adjusting a projection objective
AssigneeCarl Zeiss SMT GmbH
InventorWolfgang EMER
Life of this patent
Estimating the term…
Abstract
A projection objective having a number of adjustable optical elements is optimized with respect to a number of aberrations by specifying a set of parameters describing imaging properties of the objective, each parameter in the set having an, absolute value at each of a plurality of field points in an image plane of the projection objective. At least one of the optical elements is adjusted such that for each of the parameters in the set, the field maximum of its absolute value is minimized.
Claims19
A method for adjusting a projection objective of a projection exposure machine of the type used for microlithography in the fabrication of semiconductor components and having an illumination device for providing an illumination beam and a plurality of optical elements in the path of the illumination beam for projecting an image onto a substrate, at least some of the optical elements being capable of being adjusted for altering aberrations of the projection objective, said method comprising the steps of:
- (a) establishing an initial polarization of the illumination device;
- (b) adjusting the projection objective with respect to at least one of the aberrations under initial polarization;
- (c) changing the polarization of the illumination device from said initial polarization to a different polarization;
- and
- (d) adjusting the projection objective with respect to said at least one aberration based on said different polarization.
Dependencies are inferred from the claim text.