We find differential scanning calorimetry to be suitable for the characterization of the energetics and kinetics of interdiflusion in solder/metal diffusion couples. Differential scanning calorimetry studies of interdiffusion in Cu/Cu6Sn5 diffusion couples have shown that the driving force for interdiffusion is similar for thin film composites and for bulk diffusion couples. The heat of formation of Cu3Sn from Cu6Sn5 and Cu thin films was found to be ΔHr
= −4.3 + 0.3 kJ/mol. Portions of our differential scanning calorimetry scans are identified with diffusion limited growth of Cu3Sn. From these calorimetry data we have estimated D(cm2 / s) = Do exp(−E / kbT), where kb is Boltzmann's constant, D0 = 3.2 × 10–2 cm2/s, and E=0.87 eV/atom.