Interfacial Reaction of Sn-Ag-Cu Lead-Free Solder Alloy on Cu: A Review

Figure 8

Schematic diagram of the growth mechanism of Cu₆Sn₅ at the Sn-Ag-Cu/Cu interface: (a) individual Cu₆Sn₅ grains at the interface, (b) Cu₆Sn₅ growth along the interface, (c) the ripening process resulted in scallop Cu₆Sn₅, and (d) coarsening of scallop Cu₆Sn₅.