A simplification method of solder joints for thermal analysis in 3D packages

To guarantee the heat reliability of electronic devices, heat analysis is absolutely necessary hence the success of thermal design becomes the key to the physical design of the equipment. In this paper, a simplification method of solder joints based on mathematical derivation and heat transfer theory was proposed. In added underfill and without underfill both cases, with different diameter and solder pitch, ANSYS Workbench software was used for steady- state thermal simulation and analysis of the error of equivalent method as well. Conclusions are made that the equivalent error will be less than ± 1.0% in Z direction and ± 30.0% in X or Y direction, respectively.