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Proceedings Paper

Two-wavelength interferometry combined with N-point technique
Author(s): Joanna Schmidt
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Paper Abstract

Combining two-wavelength interferometry with the N-point technique (also called spatial carrier phase shifting interferometry) allows for the measurement of objects with large step heights that single-wavelength, phase-shifting interferometry can not correctly resolve. This combination yields some significant advantages but entails some limitations as well. Advantages include the elimination of the need for a phase shifter and the fast measurement of large step heights. The major limitations is a decrease in the measurable slope range of the object. Other concerns include setting the correct carrier frequency of the fringes for both wavelengths and coping with the magnification of the inherent phase errors of the N-point technique. The presentation considers real as well as simulated objects.

Paper Details

Date Published: 13 August 1999
PDF: 7 pages
Proc. SPIE 3744, Interferometry '99: Techniques and Technologies, (13 August 1999); doi: 10.1117/12.357713
Show Author Affiliations
Joanna Schmidt, Veeco Process Metrology (Poland)

Published in SPIE Proceedings Vol. 3744:
Interferometry '99: Techniques and Technologies
Malgorzata Kujawinska; Mitsuo Takeda, Editor(s)

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