3D Package CSP Solder Joints Morphological Parameters Sensitivity Analysis and Optimization in Temperature-vibration Coupling Environment

The finite element model of a 3D packaged CSP solder joint interconnect structure was established using ANSYS, and the temperature vibration coupling load is applied to analyze the stress-strain distribution of CSP solder joint in the model. The results show that the stress and strain distribution in the solder joints is uneven, the maximum stress and strain solder joints appear at the outermost corners of the solder joint array, and the stress and strain of the top solder joints are greater than those of the bottom solder joints. At the same time, the sensitivity analysis of the influence of CSP solder joint morphological parameters on the maximum equivalent stress was carried out. The results show that at the 95% confidence level, there are three factors that have significant effect on the maximum equivalent stress of the top layer. The order of the factors is diameter of the lower pad > height of the solder joint > volume of the solder joint. Based on orthogonal experiments and particle swarm optimization algorithm, the multi-objective optimization of CSP solder joint morphological parameters was carried out. It was found that the optimal parameters were the combination of solder joint volume 0.00818mm3, lower pad diameter 0.25mm and solder joint height 0.25mm. The result of stress calculated by simulation is smaller than that of each combination in orthogonal table. Therefore, the optimization method based on the combination of orthogonal experiments and particle swarm optimization can be applied to the optimization of 3D package CSP solder joint interconnection structure parameters.