Relationship between crystallographic structure of electroplated Cu-Sn alloy film and its thermal equilibrium diagram

The crystallographic structure of an electroplated Cu-Sn alloy film was investigated in detail using an X-ray diffraction method and electron microscopy. This structure was then compared with the thermal equilibrium diagram of Cu-Sn alloy. The structure of the plated film does not always agree with its thermal equilibrium diagram but is cross related. In this alloy system some metastable phases have been discovered. In this investigation further four kinds of metastable phases were discovered. They are two kinds of tetragonal system crystals, one kind of orthorombic crystal, and one super-saturated solid solution. The lattice constants of these crystal were also identified.