Statistical analysis of tin whisker growth

As the result of the global movement to lead-free electronics, companies which assemble semiconductor devices are switching from finishes incorporating lead to pure tin or high tin lead-free alloys. This transition has resulted in a reliability issue, concerning the formation of conductive tin whiskers which can grow across leads of a package and cause current leakage or short circuits. This paper presents the results of an experimental tin whisker growth study of bright tin on brass substrates. A probabilistic model is applied to describe the phenomenon of whisker growth in terms of whisker density, length and growth rate.