Influence of Cu orientation on the growth of Cu-Sn intermetallics and interfacial reaction of Cu/Sn diffusion couple

The copper substrates with different preferred orientations (200) and (220) were prepared and the interfacial reactions of the Cu(200)/Sn and Cu(220)/Sn diffusion couples were studied after annealing at 423K. The thickness and morphology of the intermetallic compounds were investigated. The appearance of the Cu₃Sn was observed at Cu(220)/Sn interface after aged for 4 hours and then the thickness of Cu₃Sn grown quickly. There is less Cu₃Sn at Cu(200)/Sn interface but the Cu₆Sn₅ grown quickly and quantities of voids gathered into cracks. The preferred orientations of the Cu substrates are believed to be the reasons of the different interfacial reactions phenomena.