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

Figure 11

Growth mechanism of Cu-Sn IMCs at various reflow times: (a) formation of scallop Cu₆Sn₅ at the SAC305/Cu interfacial region, (b) appearance of Cu₃Sn between the Cu₆Sn₅/Cu interface, and (c) increase in both Cu-Sn IMCs thicknesses with increasing reflow times.

(a) t < 30 s

(b) 30 s < t < 180 s

(c) 180 s < t < 600 s