In this paper we compare two non-interferometric wavefront sensors suitable for in-situ high-NA EUV optical testing. The first is the AIS sensor, which has been deployed in both inspection and exposure tools. AIS is a compact, optical test that directly measures a wavefront by probing various parts of the imaging optic pupil and measuring localized wavefront curvature. The second is an image-based technique that uses an iterative algorithm based on simulated annealing to reconstruct a wavefront based on matching aerial images through focus. In this technique, customized illumination is used to probe the pupil at specific points to optimize differences in aberration signatures.

Date Published: 27 March 2017
PDF: 6 pages
Proc. SPIE 10143, Extreme Ultraviolet (EUV) Lithography VIII, 101430N (27 March 2017); doi: 10.1117/12.2261893

Published in SPIE Proceedings Vol. 10143:
Extreme Ultraviolet (EUV) Lithography VIII
Eric M. Panning, Editor(s)