Reliability Characterization of 2.5D Multi-Chip Module on Board Under Drop Impact

In the study, the lead-free solder joint reliability and fatigue failure mechanism of an ultra-fine-pitch 2.5D multi-chip module (MCM) on board is predicted under board-level drop impact test according to JEDEC board-level test specification. To achieve the goal, the Input-G method incorporated with finite element (FE) analysis is applied to predict the transient dynamic responses of the 2.5D MCM on board. To demonstrate the effectiveness of the proposed FE model, the calculated results are compared with those obtained from experimental testing. The experimental drop test is performed on the 2.5D MCM on board with or without underfill using a JEDEC-compliant drop tester, and the associated failure mechanism is examined by way of an optical microscope. At last, the dependences of the allowed shock pulse tolerances in JEDEC drop test standard and also underfill are assessed on the dynamic behavior of the solder joints under drop impact.