Shock Recovery Test of a MEMS-Microphone

Nowadays Micro Electromechanical Systems (MEMS) can be found in a large variety of different devices. Besides from automotive or in the field for medical devices, another major global market for MEMS is the application in consumer electronics. No matter if used in laptops, smartphones, or any kind of sport gadgets, millions of devices were sold here per year. This makes non-time consuming and cost efficient productive testing mandatory, to sort out defective devices after production. Since mechanical & electrical components are involved in a MEMS, dedicated tests have to be executed for both components. Dependent on the test coverage, this has to be done either in front or back end test right before shipment. At the customer site, the MEMS may face well defined conditions during qualification process of the final device. The drop or shock of a device could be such a condition and may lead to malfunctions of the implemented MEMS. Therefore, integrated safety and compensation functions against mechanical stress are specified by IC design, to bring the MEMS back to its normal operating point. It is the test engineer's task, to test the correct behavior of these integrated functions.