Warpage Prediction of Ball Grid Array Packaging Available to Purchase

The effect of material property modeling on the warpage calculation is studied in this paper. A chip level packaging of ball grid array was considered for the simulation model. The mechanical properties of thin FR-4 and molding compound were modeled as elastic and viscoelastic based on the experimental data, and warpage developments during cooldown were calculated using different types of the mechanical property modeling. It was found that the viscoelastic characters of the FR-4 and the molding compound had significant influence on the warpage development. The results were compared with those of elastic cases, and discussions were given to analyze the deformation mechanism.