Physical characterization and sample preparation for MEMS devices

Device characterization and failure analysis of micro-electro-mechanical systems (MEMS) devices are vital steps to improve the device performance and understand the root cause of low yield. Challenges are often encountered when applying most traditional failure analysis or sample preparation methods on MEMS devices. Due to the cavities and the “floating” structures in these devices, the “floating” structures can be damaged or distorted without a good protection prior to cutting or grinding. This paper demonstrates the development of a suitable protective coating layer before FIB milling to prevent the formation of an artifact/re-deposition layer at the bottom of the MEMS device handle.