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Optical monitor for real time thickness change measurements via lateral-translation induced phase-stepping interferometry

United States Patent

June 25, 2002
View the Complete Patent at the US Patent & Trademark Office
Lawrence Livermore National Laboratory - Visit the Industrial Partnerships Office Website
An optical monitoring instrument monitors etch depth and etch rate for controlling a wet-etching process. The instrument provides means for viewing through the back side of a thick optic onto a nearly index-matched interface. Optical baffling and the application of a photoresist mask minimize spurious reflections to allow for monitoring with extremely weak signals. A Wollaston prism enables linear translation for phase stepping.
Rushford; Michael C. (Livermore, CA)
The Regents of the University of Claifornia (Oakland, CA)
09/ 564,073
May 3, 2000
The United States Government has rights in this invention pursuant to Contract No. W-7405-ENG48 between the United States Department of Energy and the University of California for the operation of Lawrence Livermore National Laboratory.