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Condenser for ring-field deep-ultraviolet and extreme-ultraviolet lithography

United States Patent

February 13, 2001
View the Complete Patent at the US Patent & Trademark Office
Lawrence Livermore National Laboratory - Visit the Industrial Partnerships Office Website
A condenser for use with a ring-field deep ultraviolet or extreme ultraviolet lithography system. A condenser includes a ripple-plate mirror which is illuminated by a collimated beam at grazing incidence. The ripple plate comprises a plate mirror into which is formed a series of channels along an axis of the mirror to produce a series of concave surfaces in an undulating pattern. Light incident along the channels of the mirror is reflected onto a series of cones. The distribution of slopes on the ripple plate leads to a distribution of angles of reflection of the incident beam. This distribution has the form of an arc, with the extremes of the arc given by the greatest slope in the ripple plate. An imaging mirror focuses this distribution to a ring-field arc at the mask plane.
Chapman; Henry N. (Livermore, CA), Nugent; Keith A. (North Fitzroy, AU)
The Regents of the University of California (Oakland, CA)
09/ 224,934
December 31, 1998
The United States Government has rights in this invention pursuant to Contract No. W-7405-ENG-48 between the U.S. Department of Energy and the University of California, for the operation of Lawrence Livermore National Laboratory.