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Curvature Model for an Ion-Machined Free-Standing Thin Film MEMS Device

Published online by Cambridge University Press:  17 March 2011

H.T. Johnson ,
P. Bierden  and
T. G. Bifano
H.T. Johnson
Affiliation:
Department of Aerospace & Mechanical Engineering, Boston University, Boston, MA 02215
P. Bierden
Affiliation:
Boston Micromachines Corp., Boston, MA 02215
T. G. Bifano
Affiliation:
Department of Manufacturing Engineering, Boston University, Boston, MA 02215
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Abstract

The connection between processing effects and curvature of a free-standing poly-Si thin film MEMS structure is analyzed theoretically and compared to experimental data. Estimates are made for the strain resulting from processing and post-processing effects including Phosphorus implantation and chemically neutral ion-beam machining. The inferred strain distribution is used to predict the curvature of the free-standing structure upon release from its host substrate. Curvature predictions agree closely with experimental measurements for particular choices of the processing strain magnitudes. The analysis procedure is proposed as a means to determine the through-thickness stress distribution in a free-standing structure. The ion-beam machining procedure is found to be a useful method for planarizing free-standing thin film structures with undesirable curvature due to process-induced stress.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 657: Symposia EE – Materials Science of Microelectromechanical Systems (MEMS) Devices III , 2000 , EE5.14
Copyright
Copyright © Materials Research Society 2001

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References

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