FEA of thermal warpage in ball grid array with consideration of molding compound residual strain compared to experimental measurements

As semiconductor devices continue to advance in terms of having smaller and denser designs, the semiconductor packages, in turn, must keep up with the changes to prevent the semiconductor chips from damages caused by internal and external factors. In this paper, a 3D finite element model was developed based on the dimensions of the actual Ball Grid Array. The material properties applied are derived from a previous study by Tsai, et al in 2008. The model was subjected to the same thermal loadings as the experiment and was compared at each temperature level. A quarter model was made and appropriate constraints were applied to determine the proper thermal warpage calculations. The molding compound residual strain was implemented using the command object feature or the Mechanical ANSYS Parametric Design Language (MAPDL). A mesh independence test was also done to determine at which mesh setting yields a stable warpage calculation. The results from the 3D simulation compared to the experimental measurements and were determined to be reasonably consistent. This validates and verifies the geometry, material properties, and boundary conditions applied to the developed 3D FEM that would be necessary for further Finite Element Analysis (FEA).