Electroplated tin can be considered as a drop-in replacement for SnPb finishes on the terminations of semiconductor devices. However, Sn layers are known to form whiskers. These whiskers are spontaneous protrusions of few microns in diameter and up to hundreds of microns
or even millimetres in length. These might cause shortcircuits and the failure of electronic circuits. This paper shows that no accelerated test method is available for whisker growth and presents a mechanism for whisker growth, based on compressive stress that is introduced by irregular growth of intermetallics at the substrate/plating interfaces. This mechanism is illustrated with views of the intermetallics and diffusion theory. Furthermore, countermeasures to prevent whisker growth are presented. These countermeasures are explained with the help of the above-menP.J.T.L. Oberndorff, M. Dittes, L. Petit, C.C. Chen, J. Klerk and E.E. de Kluizenaartioned mechanism.
or even millimetres in length. These might cause shortcircuits and the failure of electronic circuits. This paper shows that no accelerated test method is available for whisker growth and presents a mechanism for whisker growth, based on compressive stress that is introduced by irregular growth of intermetallics at the substrate/plating interfaces. This mechanism is illustrated with views of the intermetallics and diffusion theory. Furthermore, countermeasures to prevent whisker growth are presented. These countermeasures are explained with the help of the above-menP.J.T.L. Oberndorff, M. Dittes, L. Petit, C.C. Chen, J. Klerk and E.E. de Kluizenaartioned mechanism.
