Design, Fabrication, and Characterization of Single Crystal Silicon Latching Snap Fasteners for Micro Assembly

A snap fastener is a deformable device consisting of a pair of mating surfaces that \snap" together during assembly. Because of the simple, linear assembly motion, such latching micro fasteners have a wide range of applications in micro assembly tasks, e.g. for devices with multiple or layered components, or micro opto-mechanical plugs. At the micro scale, conventional types of fasteners like screws and hinges are unlikely to work due to present fabrication constraints and large friction forces. Micro snap fasteners also have great potential to be used as sensors with memory. We present a detailed theoretical analysis of design and function of micro snap fasteners, and describe the fabrication in single crystal silicon (SCS) technology. We perform experiments on snap fasteners with 1 { 2 m wide latches. Independent comb drive actuators generating micro-Newton forces were used for actuation of the fasteners to verify the theoretically obtained design rules. Our experimental results are in close accordance with the theoretical predictions.