Abnormal grain growth of Ni3Sn4 at Sn-33Ag/Ni interface

Abstract

By the reaction of molten solder alloy with compositions of 96.5Sn-3.5Ag (compositions are all in weight percent unless specified otherwise) with either the thick Cu or the thick Ni substrate at 250degreesC, the rounded Cu6Sn5 grains formed over Cu and the faceted Ni3Sn4 grains precipitated over Ni. As the soldering time changed from 1 min to 60 min, normal grain growth occurred for rounded Cu6Sn5 grains while abnormal grain growth (AGG) mode was observed for faceted Ni3Sn4 grains. The measured grain size distributions also confirmed the difference between normal grain growth and abnormal grain growth.