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Proceedings Paper

Simultaneous profiling of optically smooth and rough surfaces using dual-wavelength interferometry
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Paper Abstract

Interferometers are widely used in industry for surface profiling of microsystems. It can be used to inspect both smooth (reflective) and rough (scattering) surfaces in wide range of sizes. If the object surface is smooth, the interference between reference and object beam results in visible fringes. If the object surface is optically rough, the interference between reference and object beam results in speckles. Typical microsystems such as MEMS consist of both smooth and rough surfaces on a single platform. Recovering the surface profile of such samples with single-wavelength is not straight forward. In this paper, we will discuss a dual-wavelength approach to measure surface profile of both smooth and rough surfaces simultaneously. Interference fringe pattern generated on a combined surface is acquired at two different wavelengths. The wrapped phases at each wavelength are calculated and subtracted to generate contour phase map. This subtraction reveals the contour fringes of rough and smooth surfaces simultaneously. The dual-wavelength contour measurement procedure and experimental results will be presented.

Paper Details

Date Published: 14 February 2020
PDF: 6 pages
Proc. SPIE 11249, Quantitative Phase Imaging VI, 112491I (14 February 2020); doi: 10.1117/12.2543917
Show Author Affiliations
Paul Kumar Upputuri, Nanyang Technological Univ. (Singapore)
Praveenbalaji Rajendran, Nanyang Technological Univ. (Singapore)
Manojit Pramanik, Nanyang Technological Univ. (Singapore)

Published in SPIE Proceedings Vol. 11249:
Quantitative Phase Imaging VI
Yang Liu; Gabriel Popescu; YongKeun Park, Editor(s)

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