Identification of Residual Stress State in an RF-MEMS DeviceN
Microelectromechanical Systems (MEMS) are among the most significant technological advances of this decade. The objective of this technology is to manufacture "systems" whose dimensions are only a few hundred microns. Devices with applications ranging from drug delivery systems to telecommunications are currently under development. Their reduced size and weight give them unique advantages. The study of "thin films" and "ultra thin films" employed in MEMS devices is being vigorously pursued. However, it is far from complete. Each MEMS device that is considered seems to exhibit differences in mechanical behavior and introduces new fundamental questions. This is a consequence of the strong effect that size introduces on fracture, plasticity, friction, and fatigue.
In this investigation, Young's modulus and residual stress state of a freestanding thin membrane are characterized by means of wafer level tests. The membrane is part of an RF MEMS Switch manufactured by Raytheon Systems. The investigation uses a new method that combines nanoin-dentation, a Membrane Deflection Experiment (MDE) and 3D numerical simulations.