Finite Element Analysis of Dynamic Drop Impact of Board-level Stacked-Die Packages Using Submodeling Technique

The objective of this research is to investigate the effects of board-level drop test based on the support excitation scheme incorporated with the submodel technique for stacked-die packages. Three lead-free materials, namely SAC405 (Sn4Ag0.5Cu), SAC387(Sn3.8Ag0.7Cu) and Sn3.5Ag were used to demonstrate the transient dynamic response for solder balls subject to JEDEC pulse-controlled board-level drop test standard JESD22-B110A Condition B[1]. The support excitation scheme was developed and applied to examine the transient dynamic response for it produces no rigid-body motion to the test vehicle and dramatically reduces the computational cost. In order to evaluate the structure of the interested area, a strip model sliced from the full test vehicle is used in this research. In addition, the submodel region is particularly chosen with strip model by performing the cut boundary interpolation. The envelope of equivalent stress for the outermost solder joint off the end of the strip model is plot to show the potential solder failure mode and mechanism. The cut boundary of submodel is verified and the mesh density of submodel is examined. For a refinery mesh of submodel, parametric studies are carried out to study the reliability of the outermost solder joint, and the results are summarized as design rules for the development of stacked-die packages.