Textured growth of Cu₆Sn₅ grains formed at a Sn3.5Ag/Cu interface

The growth orientations of Cu₆Sn₅ grains formed at a Sn3.5Ag/polycrystalline Cu interface were investigated. Similar as reported on Cu single crystals, strong textures in Cu₆Sn₅ layers can also form on polycrystalline Cu, but the texture formation mechanisms differ. The texture formation on polycrystalline Cu occurs during the ripening growth and results from the differences in stability of the interfacial grains with various orientations at different temperatures. A reaction temperature of 240 °C causes the Cu₆Sn₅ layer to form [0001] texture in the direction normal to the substrate, and a special morphology of interfacial Cu₆Sn₅ grains can be formed on this layer to reinforce joint properties.