Finite Element Modeling of SnAgCu Alloy on 3D ...

The objective of this research is to investigate the solder joint reliability of board-level 3D pyramid package-on-package (POP) stacked-die packages in transient drop analysis. Three kinds of lead-free solder alloy, Sn4Ag0.5Cu, Sn3.5Ag0.5Cu and Sn3.5Ag are introduced to demonstrate the transient dynamic response subjected to JEDEC sine wave pulse-controlled drop test. In order to evaluate the structure of the interested area a strip model sliced from, the full test vehicle is introduced in this research. In addition, the submodel region is particularly chosen with the 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 drawn to illustrate the potential failure sites 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 for structure and material are carried out to investigate the reliability of the outermost solder joint, and the results are summarized as design rules for the development of 3D IC packages. A series of comprehensive parametric studies are conducted in this research.