Failure Mechanism and Predictive Modeling for Microbump Interconnects Drop Life Under Diverse Impact Angles in Advanced Packaging

With the advancement of Moore’s Law, the impact reliability of solder joints has emerged as a critical concern due to the reduction in their size. The board-level drop test, based on the JEDEC standard, is widely employed by researchers to assess the impact performance of electronic packages. Typically, these tests are conducted with boards placed horizontally. However, real-world service environments involve impacts at various angles that can lead to different failure mechanisms in solder joints. In this study, we investigate the impact reliability of microbump interconnect structures under different impact angles. By considering plastic strain analysis, we demonstrate that drop impacts at other angles can be equivalently represented by the scenario with drop angle $\alpha =$ 0° impact. Subsequently, we analyze the failure mechanism of microbumps during drop tests and propose a predictive model for their drop life under varying impact angles. Our results indicate that as the drop angle increases, there is a transition in the driving force for microbump failures from tensile and compressive stress to shear stress. The proposed life prediction model exhibits an error rate below 25% and effectively forecasts the drop life of microbumps in advanced packaging.