An Interferometric Platform for Static, Quasi-Static, and Dynamic Evaluation of Out-Of-Plane Deformations of MEMS and MOEMS
Christophe Gorecki , Michał Józwik , Delobelle Patrick
AbstractIn this chapter, we demonstrate a low-cost and multifunctional interferometric platform based on a Twyman–Green interferometer (TGI) for testing microelectromechanical systems/microoptoelectromechanical systems (MEMS/MOEMS). This technique may be used for relatively smooth surfaces to measure the 3-D map of out-of-plane displacements. It provides both micromechanical and material properties of buckled membranes, quasi-static actuator behavior, and vibrational analysis of microdevices. A specific metrology procedures have been demonstrated to determine the residual stress of silicon membranes prestressed by silicon oxinitride (SiOxNy) grown by plasma-enhanced chemical vapor deposition (PECVD). Because material properties of SiOxNy films depend strongly on details of the PECVD process, the relationship between the micromechanical properties, physicochemical characteristics, and, finally, the optical properties of SiOxNy thin films are established carefully. Interferometric technique measures also complete deflection curves of the electrostatically actuated SDA plate. The experimental results obtained by this technique are compared with numerical data calculated by FEM. When operating under a stroboscopic regime, the same interferometer allows the full-motion measurement of moving microstructures, demonstrated in the case of the response of a piezoelectric actuator and electrostatically driven torsional mirror. For vibration measurements, each of the microelements is vibrated by applying a sinusoidal voltage from a waveform generator. This generator also drives the switching electronics of the pulsed diode laser. The two channels of the waveform generator are synchronized with an adjustable phase delay, and the 3-D map of resonating modes is measured. The new generation of industrial test equipment for micro production have to be time and cost efficient. The concept introduced in section 12.6 is based on a parallel inspection approach. An array of micro-interferometers integrated on a probing wafer is adapted to the M(O)EMS wafer under test and provides 25 measurements within one measurement cycle.
|Publication size in sheets||1.45|
|Book||Osten Wolfgang (eds.): Optical Inspection of Microsystems (Second Edition), 2020, CRC Press / Balkema, ISBN 978-1-4987-7947-0, 570 p.|
|Score||= 20.0, 26-11-2019, MonographChapterAuthor|
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