Monotonic and fatigue testing of freestanding submicron thin beams application for MEMS

A freestanding submicron thin film specimen is designed and fabricated here to carry out a series of monotonic and fatigue testing. This freestanding beam was loaded by performing monotonic loading/unloading or closed-loop load controlled tension–tension fatigue experiments on it. Loading was applied using a piezoelectric actuator with 0.1 μm resolution connected to the test specimen. Loads were measured by connected a capacitor load cell with a resolution of less than 0.1 mN. The modulus, yield stress and maximum stress of tested submicron thin films at room temperature were found from monotonic loading/unloading tests. The results of 300 nm copper thin films fatigue experiments demonstrated a trend of decreasing cycles to failure with increasing loading amplitude and increasing mean stress.