Abstract
Effects of 0.1 wt% Al addition to Sn-1Ag-0.5Cu (SAC105) on the structure of solder/copper interface have been studied. The solder/copper joint assembly was prepared by dip soldering process at 250 A degrees C for 10 s and then aged thermally at 150 A degrees C for 500 h for an accelerating aging test. Results show that the addition of Al does not change the type of the reaction product with the Cu substrate. The reaction product is always Cu6Sn5 and Cu3Sn phases formed at the solder/copper interface. However, it is found that the addition of Al retards the interfacial reaction and suppresses the growth of interfacial intermetallic layer(s). Potential mechanisms are proposed to explain the effects of Al addition on the solder/copper interfacial reactions.