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Proceedings Paper

Resonance measurements of stresses in Al/Si3N4 microribbons
Author(s): Alexander P. Payne; Bryan P. Staker; Christopher S. Gudeman; Michael J. Daneman; Donald E. Peter
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Paper Abstract

Film stresses in doubly-supported bi-layer micro-ribbons have been determined by measurement of their resonant vibration frequency. The composite aluminum/silicon-nitride ribbons constitute a programmable diffraction grating in which ribbon stresses play an important role in device behavior. To determine the intrinsic film stresses in each layer, special ribbon arrays were fabricated in which the coverage of aluminum was systematically varied from end toward the center of each ribbon. With increasing aluminum coverage, the ribbons exhibit a characteristic roll-off in resonant frequency which can be used to refine longitudinal film stresses. An analytical expression describing resonant frequency as a function of partial layer coverage is derived. By least-squares fitting this function to the observed roll-off, the film stresses in each layer are determined. It is found that the silicon-nitride stresses are large and tensile (approximately 800 MPa), while those in the aluminum are small and compressive (approximately -100 MPa).; This paper reviews the relevant theory behind the approach, demonstrates its application to wafer- level data and discusses its repeatability and accuracy.

Paper Details

Date Published: 18 August 1999
PDF: 11 pages
Proc. SPIE 3880, MEMS Reliability for Critical and Space Applications, (18 August 1999); doi: 10.1117/12.359358
Show Author Affiliations
Alexander P. Payne, Silicon Light Machines (United States)
Bryan P. Staker, Silicon Light Machines (United States)
Christopher S. Gudeman, Silicon Light Machines (United States)
Michael J. Daneman, Silicon Light Machines (United States)
Donald E. Peter, Silicon Light Machines (United States)


Published in SPIE Proceedings Vol. 3880:
MEMS Reliability for Critical and Space Applications
Russell A. Lawton; William M. Miller; Gisela Lin; Rajeshuni Ramesham, Editor(s)

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