Chapter 13 - MEMS Testing

Abstract

A majority of microelectromechanical systems (MEMS) devices are inherently mechanical in nature and therefore require some special considerations during various manufacturing stages and testing. This chapter discusses some of the important handling considerations during dicing, packaging, and testing. There are a wide variety of test methods, such as electrical, optical, mechanical, and environmental, for characterization of various MEMS devices. This chapter reviews the instrumentation, typical setup, and important characteristics for testing a wide variety of MEMS devices, including accelerometers, gyroscopes, humidity sensors, RF MEMS, optical MEMS, pressure sensors, and microphones. It is primarily the diversity of MEMS devices and their working principles that have prevented the development of universal design-for-testability (DFT) and built-in self-test (BIST) solutions for all types of MEMS in general. As a result, different DFT/BIST solutions are required for different types of MEMS. The discovery of such solutions needs a thorough understanding of various MEMS defects, fault models, and their associated failure mechanisms. This is further complicated by the variety of physical/chemical stimuli for MEMS devices including acceleration, pressure, heat, and chemical concentration, to name a few. In BIST for MEMS, such stimuli must be generated automatically on-chip. The on-chip generation of non-electrical test stimuli such as chemical or fluidic inputs for bioMEMS testing has also been difficult.