An investigation was made of the effects of passing electric currents (500A/cm2) through Sn/Ag couples which had been annealed at 120 and 160C. The results showed that, when the direction of electron flow was from Sn to Ag, it enhanced the growth of Ag3Sn at the

interface. It retarded Ag3Sn growth when the electrons flowed from Ag to Sn. Similar results were found for the Sn/Ni system, where Ni3Sn4 formed in Sn/Ni couples annealed at 160 and 180C. The growth rate of the Ni3Sn4 increased when the electrons flowed from Sn to Ni, and decreased when the direction of electron flow was reversed. The thicknesses of the reaction layers was measured, and apparent effective charges were determined for Sn. Their values decreased with increasing temperature; thus indicating that the effect of electromigration on interfacial reactions became less significant at higher temperatures.

Electromigration Effect upon the Sn/Ag and Sn/Ni Interfacial Reactions at Various Temperatures. C.M.Chen, S.W.Chen: Acta Materialia, 2002, 50[9], 2461-9