Study on the delamination of composite materials and metals in PBGA and LFBGA

Abstract

Package delamination is a common problem in electronic packaging, and this study focused on the low-profile fine-pitch ball grid array (LFBGA) and plastic ball grid array (PBGA) package of composite and metal bonding and bonding mechanism to decrease the occurrence of delamination. In LFBGA, the physical and chemical properties were discussed by roughness and pure copper/nickel bonding experiment. In PBGA, delamination occurred between the corner of the heat sink and the epoxy resin, so the PBGA package process was simulated by the finite element method; moreover, the model was established and simulated by computer software ANSYS. The chip size, chip thickness and shoulder width were chosen as the parameters of response surface methodology (RSM). Finally, the results showed that the shoulder width has the greatest degree of influence on the stress concentration, and the shoulder width has negative correlation with stress value. In addition, the original design of the PBGA heat sink was changed, which the corner of the heat sink was changed to chamfer shape. From the results of the simulation, when the chamfer radius was larger, the stress value had decreased.