材料期刊网

The growth, transformation, and lattice structure of intermetallic compounds formed between Sn-0.3Ag-0.7Cu lead-free solder and copper substrate were investigated. Dip soldering was used to initiate the reaction between the solder and substrate. An μ-Cu₆Sn₅ intermetallic phase possessing a hexagonal lattice structure was found at the as-soldered interface. Thermal aging at a number of conditions resulted in the formation of a Cu₃Sn intermetallic phase between the Cu₆Sn₅ layer and the copper substrate. ε-Cu₃Sn with an orthorhombic lattice structure was found together with hexagonal Cu₃Sn. Subsequently, the activation energies of the intermetallic phases were calculated and compared to results obtained from the literature. The comparison showed that good agreement existed between the findings from this study and literature data within a similar temperature range.