On the Nature of the Interface between Ag^sub 3^Sn Intermetallics and Sn in Sn-3.5Ag Solder Alloys

We report on the nature of the orientation of Ag^sub 3^Sn and the Ag^sub 3^Sn/Sn interface in Sn-3.5Ag solder. Orientation imaging microscopy (OIM) and transmission electron microscopy (TEM) were used to characterize the orientation and nature of the interface, respectively. OIM and TEM showed that Sn-3.5Ag containing spherical Ag^sub 3^Sn particles does not have a preferred orientation with respect to the Sn matrix. However, needle-like Ag^sub 3^Sn formed during slower cooling appeared to have a preferred orientation within individual Sn colonies. The interface between Sn and Ag^sub 3^Sn appeared to be incoherent, as confirmed by high-resolution TEM analysis. [PUBLICATION ABSTRACT]