Investigation on the effect of the packaging-induced stress on the reliability of a MEMS sensor package

Currently, with the increasing trend towards miniaturization and thinning of semiconductor devices, ensuring product reliability has become a crucial aspect in electronic packaging. This paper specifically focuses on MEMS temperature and humidity sensors and utilizes Moldex3D software for three-dimensional mold flow simulation analysis. The purpose of the analysis is to predict the distribution of potential air traps and identify the locations of weld lines. The influence of gate location and gate quantity on process defects and reliability issues is investigated using a single-factor method. The results clearly indicate that the design of the gate system has a significant impact on the reliability of sensor packaging. The simulation results for different gate locations demonstrate that placing the gate in the middle achieves a more balanced flow of epoxy resin. However, insufficient filling pressure in this configuration may result in an increase in the occurrence of air traps and weld lines. When multiple gates are used in the simulation, it is observed that the number of air traps does not decrease with an increase in the quantity of gates. Nonetheless, multiple gates promote a more balanced resin flow, although some convergence occurs, leading to the generation of numerous air traps at the convergence points. Additionally, excessive injection pressure can cause overflow and wire shifting at the window opening of the temperature and humidity sensor. In conclusion, the design of the gate system should carefully consider the structural characteristics of the product and the transfer molding process. It is evident that the gate system design plays a crucial role in the formation of air traps and weld lines. Therefore, a rational gate system design is vital to ensure both the yield and reliability of sensor products.