Design of solder joints for self-aligned optoelectronic assemblies

Self-aligning soldering is the critical technology for precision optoelectronic assembly. The pre-assembly solder joint design can improve the final alignment accuracy. In this paper, a public domain software Surface Evolver is modified as a modeling tool for the design of solder joints for self-aligned assemblies. Furthermore, for convenient and efficient design, the results from the numerical model are nondimensionalized and regressed as a polynomial regression model, which describes the relationships between the surface tension forces and the solder joint design parameters explicitly. The regression model is established based on 1100 data points calculated for solder joints with circular pads. We apply this model tool to several design case studies, including the joint array design for self-alignment and the solder assembly of a FLC/VLSI spatial light modulator. It is demonstrated that the model developed here is a very powerful and convenient tool to aid in the design of solder joints for various applications