A differential equation method has been developed for the design of soft x-ray projection lithography systems. This method yields numerical values for the sag and slope of two surfaces within a multi-mirror projection system such that the Abbe Sine condition and the constant optical path length condition are satisfied. Application of this design method to three- and four-mirror systems is in progress. Results are compared to optical performance of similar systems designed by conventional methods.
This article is from 'OSA Proceedings of the Topical Meeting on Soft-X-Ray Projection Lithography Held in Monterey, California on 10-12 April 1991. Volume 12', AD-A252 998, p22-26.