Structure optimization design of BGA solder joints based on surface response method

Due to low cost and good electrical performance, BGA packaging is widely used in integrate circuit (IC) industry. Finite element method (FEM) analysis was carried out for evaluation of stress distribution in the Ball Grid Array (BGA) solder joints, and the radial scale, the height, the spacing of the solder joints, the height of chip were selected as design factors. Response surface methodology (RSM) was used to generate 25 designs and finite element modeling was employed to simulate the response of the assemblies to reliability influencing simulation calculations. The equation regression was associated with genetic algorithm (GA) to search for an optimal combination of parameters that meet the thermal vibration quality characteristics. The confirmation results showed that the space played a role in the reliability, and the radical scale 0.28 mm, the height 0.20 mm, the spacing 0.4mm settings of produce optimal assembly which demonstrated potential of reducing equivalent stress of the best design by 11.92%, respectively. The aim of optimizing BGA solder joints parameters was succeeded.