Quasi-Static Modeling of the Self-Alignment Mechanism in Flip-Chip Soldering—Part I: Single Solder Joint

A three-dimensional mathematical model simulating the self-alignment mechanism in the flip-chip soldering of a single joint has been developed. Based on the principle of energy minimization, it calculates the quasi-static surface profiles defined by the size of the solder pads, the solder volume, the surface tension coefficient, the vertical loading and the misalignment. The model is capable of calculating initial, intermediate and final profiles and their associated restoring forces during the solder reflow. It can provide the guidelines to improve the assembly yield and the stress-related reliability of the flip-chip soldering technology.