Finite element analysis of lead-free surface mount devices

Transition to lead-free solder materials has raised concerns over the reliability of lead-free solder joints in the electronic industry. Solder joints provide electrical conduction and mechanical support for components and may operate over temperature extremes of -55oC to 125oC or greater. These temperatures are relatively high the melting point of the solder. A mismatch between coefficients of thermal expansion of the component, solder and substrate, combined with thermal variations during service, results in thermal fatigue that is a common failure mechanism for solder joints in electronic products. So far most of the studies of this issue have considered uniform temperature distributions in the electronic assembly. The main objective of this paper is to investigate the effect of the experimentally observed non-uniform temperature distribution in the electronic device on the structural response of solder joints in comparison with that for a uniform temperature distribution.