The assembly of an optical system requires the correction of aberrations in the entire imaging field by making selected rigid-body motions of the optical elements. We present a rigorous method for determining which adjustment motions, called compensators, to use for alignment. These compensators are found by employing techniques from linear algebra that choose the most independent vectors from a set which are interdependent. The method finds the applied to a four-mirror scanning ring-field EUV lithography system. It is shown that out of 32 degrees of freedom in the configuration of the optical elements, only eight compensators are required on the optics. By adjusting these compensators a misaligned configuration giving 30(lambda) wavefront error can be assembled to (lambda) /50 in the absence of measurement noise.

Date Published: 5 June 1998
PDF: 12 pages
Proc. SPIE 3331, Emerging Lithographic Technologies II, (5 June 1998); doi: 10.1117/12.309562

Published in SPIE Proceedings Vol. 3331:
Emerging Lithographic Technologies II
Yuli Vladimirsky, Editor(s)