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ISSN Online: 2377-424X

International Heat Transfer Conference 12
August, 18-23, 2002, Grenoble, France

Interferometric Imaging System for Measuring Out-of-Plane Deflection in MEMS Devices

Get access (open in a dialog) DOI: 10.1615/IHTC12.3920
6 pages

Abstract

Due to the small dimensions of microelectromechanical systems (MEMS), imaging and metrology techniques must be developed for characterizing MEMS devices. This paper describes an interferometric imaging system used to measure out-of-plane deflection of stiction-failed MEMS cantilevers. The system is constructed on an optical table with stock optics. Using a HeNe laser with a wavelength of 632.8 nm, at which polysilicon is semitransparent, interference occurs between lightwaves reflected from the top of the microstructure and lightwaves transmitting through the microstructure and reflecting off the substrate. The interference produces fringes along adhered microstructures corresponding to the deflection. The accuracy of the technique is illustrated by comparing images from the system to images captured using a Michelson interferometric microscope. Suggestions for improving the image quality including the resolution and contrast are also discussed along with how the technique can be applied to other applications.