Mechanism analyses on PBGA strip packaging warpage

The objective of this study is to analyze warpage development mechanism by simulating a strip type packaging for plastic ball grid array. Molding compound and substrate materials were thermo-mechanically tested to obtain the mechanical properties by several test methods. Samples were fabricated using the same materials, and warpage developments were measured at room temperature after molding compound cure. The results were compared with the measurement data of the samples, and the warpage mechanism was investigated based on the elastic and viscoelastic simulation results. The development mechanism was analyzed through the simulation calculations by combining different material properties modeling and geometries. It was found that the relaxation behaviors of the molding compound and the substrate materials, and the packaging geometry had significant effects on the warpage development. The development mechanism was comprehensively discussed based on the results.