Abstract
Creep is a time-dependent deformation mechanism that affects the reliability of metallic MEMS. Examples of metallic MEMS are RF-MEMS capacitors/switches, found in wireless/RF applications. Proper modeling of this mechanism is yet to be achieved, because size-effects that play a role in MEMS are not well understood. To understand this better, a methodology is setup to study creep in Al-Cu alloy thin film micro-cantilevers micro-fabricated in the same MEMS fabrication process as actual RF-MEMS devices. The methodology entails the measurement of time-dependent deflection recovery after maintaining cantilevers at a constant deflection for a prolonged period. Confocal profilometry and a simple mechanical setup with minimal sample handling are applied to control and measure the deformation. Digital image correlation, leveling and kinematics-based averaging algorithms are applied to the measured surface profiles to correct for various errors and improve the precision to yield a precision < 7% of the surface roughness. A set of measurements is presented in which alloy microstructure length scales at the micrometer-level are varied to probe the nature of this creep behavior.
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Bergers, L.I.J.C., Hoefnagels, J.P.M., Geers, M.G.D. (2011). Creep measurements in free-standing thin metal film micro-cantilever bending. In: Proulx, T. (eds) MEMS and Nanotechnology, Volume 4. Conference Proceedings of the Society for Experimental Mechanics Series. Springer, New York, NY. https://doi.org/10.1007/978-1-4614-0210-7_24
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DOI: https://doi.org/10.1007/978-1-4614-0210-7_24
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