Effects of silver addition on Cu–Sn microjoints for chip-stacking applications

Ag3Sn Compounds Coarsening Behaviors in Micro-Joints

“…To date, some research has been conducted into the coarsening behaviors of Ag 3 Sn compounds over time [16,17]. Most of studies placed their emphasis on thermal aging influences, and found that Ag 3 Sn coarsening is visible as the aging time increased, indicating that such coarsening behaviors follow the Ostwald ripening principle [13,18]. It is worth noting that the reliability of solder joints with large Ag 3 Sn particles are significantly sensitive to thermal cycling loading, since thermally induced stresses commonly concentrate at the interface of the solder matrix, and large Ag 3 Sn particles [19].…”

Interfacial Energy Effect on the Distribution of Ag3Sn in Full Intermetallic Joints

“…When the solder layer was completely consumed, all the Ag 3 Sn particles located near the centerline of the joints, now fully occupied by Ni 3 Sn 4 . However, such a microstructure evolution was not observed in the Cu/SnAg/Cu system . In this system, Ag 3 Sn particles were not pushed toward the centerline by the advancing Cu 6 Sn 5 /Sn interface but were entrapped between the Cu 6 Sn 5 grains, as illustrated in Figure b.…”

“…Silver was reported to be inert in soldering reactions in the sense that Ag did not become incorporated into the reaction products of the soldering reactions, including Ni 3 Sn 4 , Cu 6 Sn 5 , and Cu 3 Sn . During the reactions, Ag in Sn remained in the form of Ag 3 Sn, even when all the Sn had been consumed . The spatial distribution of the Ag 3 Sn particles within the full intermetallic joints, however, is an important issue that has never been properly addressed.…”

“…The fabrication processes and the specifications for the Cu/Sn3.5Ag/Cu sandwiches used in this study had been described previously, and the details are omitted here for brevity. In short, the sandwiches were fabricated through chip‐to‐chip thermal compression bonding at 250 °C for 1 min.…”

Low temperature bonding for high temperature applications by using SnBi solders

“…The fabrication processes and the specifications for the Cu/ Sn5Bi/Cu, Cu/Sn10Bi/Cu, and Cu/Sn58Bi/Cu sandwiches used in this study are very similar to those described previously [12], and the details are omitted here for the sake of brevity. In short, the sandwiches were fabricated through chip-to-chip thermal compression bonding at 250 C for 1 min.…”