In situ study of the real-time growth behavior of Cu6Sn5 at the Sn/Cu interface during the soldering reaction

The growth behavior of intermetallic compound (IMC) at the Sn/Cu interface during the soldering reaction was studied using synchrotron radiation real-time imaging technology. The annexation behavior of adjacent IMC grains, which slowed down with the soldering process, was directly observed for the first time. The IMC grains undergoing annexation tended to maintain a hemispherical morphology which was influenced by the radius of curvature of the nearest IMC grain. The annexation behavior was driven by the Gibbs-Thomson effect.