Solder joint shape and standoff height prediction and integration with FEA-based methodology for reliability evaluation

Abstract

Solder joint fatigue failure is a common failure mechanism in semiconductor packages mounted on boards. The thermal expansion mismatch between the package and the board causes cyclic loading on the solder joints during temperature cycling. It is therefore important to model the solder joint shape and standoff height accurately to estimate the reliability of a solder joint assembly. This paper discusses details of solder shape prediction using the Surface Evolver tool and its validation with experimental data. A comparison with truncated sphere model is also provided. A strategy for importing Surface Evolver data into a finite element based reliability evaluation is outlined.