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Proceedings Paper

Long-term reliability measurements on MEMS using a laser-Doppler vibrometer
Author(s): J. De Coster; L. Haspeslagh; A. Witvrouw; I. De Wolf
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Paper Abstract

This paper describes how a standard laser-Doppler vibrometer (LDV) system was modified and extended for long-term reliability measurements on micro-electromechanical (MEMS) devices. Since scanning LDV measurements are performed by successively pointing a laser beam at a predefined set of locations, it is of the utmost importance that no movement of the MEMS device relative to the laser source occurs during the extended lifetime testing period. In the proposed system, the inevitable drift is compensated in three dimensions. The Z-drift is compensated by a piezo-actuated lens and an autofocus algorithm. The in-plane drift is detected using an image correlation technique, and the coordinate system of the LDV tool is modified accordingly. In this manner the scan points of the LDV can track the drift of the MEMS device. During a 400-hour testing period, measurements were performed every 15 minutes. A total in-plane drift of about 30μm was observed. The tracking error was below the resolving power of the microscope.

Paper Details

Date Published: 3 October 2008
PDF: 9 pages
Proc. SPIE 7155, Ninth International Symposium on Laser Metrology, 71550G (3 October 2008); doi: 10.1117/12.814515
Show Author Affiliations
J. De Coster, IMEC (Belgium)
L. Haspeslagh, IMEC (Belgium)
A. Witvrouw, IMEC (Belgium)
I. De Wolf, IMEC (Belgium)
Katholieke Univ. Leuven (Belgium)

Published in SPIE Proceedings Vol. 7155:
Ninth International Symposium on Laser Metrology
Chenggen Quan; Anand Asundi, Editor(s)

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