Accurate assessment of packaging stress effects on MEMS devices

In this work, packaging-induced stress effects are assessed for MEMS (micro-electro-mechanical systems) sensors in several plastic packages. A packaged MEMS sensor may experience functionality offset shifts due to the thermo-mechanical stresses induced by plastic packaging and the subsequent assembly processes. Modeling and simulation to minimize the stress-induced shifts is essential for high-precision accelerometers and gyroscopes. Improvement of modeling accuracy by correlating FEA models with measured material properties and package warpage is presented with LFCSP packages. Using the refined reduced order MEMS sensor/package/PCB interaction (MPPI) model, device offset performance is simulated and compared with actual data collected for 3-axis accelerometer