Epitaxial growth of intermetallic compounds formed at eutectic Sn37Pb/polycrystalline Cu interface during solid-state aging

Epitaxial growth of intermetallic compounds formed at eutectic Sn37Pb/ polycrystalline Cu interface during solid-state aging. The results show that the interfacial Cu₆Sn₅ grains exhibit textured growth under solid-state condition and their preferred orientations are affected by the as-soldered joints. Cu₆Sn₅ grains with [0001] direction normal to the interface are stable in solid and molten Sn37Pb solder at 200°C, but will be rapidly consumed at 280°C, which leads to the formation of different textures in Cu₆Sn₅ layer during the solid-state aging treatment to the joints formed at 200°C and 280°C. Also, the effects of the texture evolution on the growth of interfacial IMCs are evaluated. The results show that Cu diffusion along [0001] direction of Cu₆Sn₅ is faster and therefore more interfacial IMCs are generated in the joints formed at 200°C than those formed at 280°C under the same solid-state reaction conditions.