First-Principles calculations of structural, thermodynamic and electronic properties of intermetallic compounds in solder

摘要

First principles calculations have been performed to investigate the structural, thermodynamic and electronic properties of four common intermetallic compounds (IMCs) formed at the solder joints of electronic packages, namely, Cu6Sn5, Cu3Sn, Ni3Sn4 and Ag3Sn. The theoretical heat of formation of Cu6Sn5 is close to that of Cu3Sn, both of them are overestimated relative to the experimental results. In addition, Ni3Sn4 has the lowest heat of formation among these IMCs. The curves of total DOS near the Fermi level for the IMCs are mainly dominated by the Sn-sp hybridization states, M (M=Cu, Ni, Ag)-sp hybridization states and M-d states. The complicated bonding states for Ni3Sn4 may caused by the position of the main peak of Ni-d states.