Microstructure evolution of Au/SnSb-CuNiAg/(Au)Ni during high temperature aging

Abstract

Purpose The purpose of this paper is to investigate the morphology evolution and the composition transformation of Au-Sn intermetallic compounds (IMCs) of the new Au/Sn-5Sb-1Cu-0.1Ni-0.1Ag/(Au)Ni solder joint during the high temperature aging. Design/methodology/approach Sn-5Sb-1Cu-0.1Ni-0.1Ag solder balls (500 µm in diameter), heat sink with structure of 7.4 µm Au layer on 5 µm Ni-plated Cu alloy and Si chip with 5.16 µm plated Au were used to fabricate micro-solder joints. The joints were performed in a furnace at 150°C for 150, 250 and 350 h aging. The samples were polished and deep etched before analyzed by metallographic microscope and scanning electron microscopy, respectively. Energy dispersive x-ray spectroscopy was used to identify the composition of the IMCs. Findings ß-(Au,Ni,Cu)10Sn phase is formed during the soldering process. The IMCs evolution has two periods during the aging. The first is the ξ-(Au,Ni,Cu)5Sn, ξ-(Au,Cu)5Sn and δ-AuSn were formed and grew to form a full-compound joint after about 150 h aging. The second is the conversion of the full-compound joint. The IMCs converted to ξ′ phase when the aging time extends to 250 h, and transformed to ε-(Au,Ni,Cu)Sn2 and η-(Au,Ni,Cu)Sn4 after 350 h aging. The thicker gold layer and thinner solder joint can promote the growth of the IMCs. ß-(Au,Ni,Cu)10Sn emerged in Au/SnSb-CuNiAg/(Au)Ni in this research, which is not usually found. Originality/value The results in this study have a significant meaning for the application of the new Sn-5Sb-1Cu-0.1Ni-0.1Ag in harsh conditions.

Effect of Cu, Ni, Ag addition on creeping properties of Sn5Sb-0.5Cu-0.1Ni-0.5Ag for high temperature packaging

“…As shown in the figure, the Cu/Sn5Sb-0.5Cu-0.1Ni-0.5Ag/Cu had a better creep resistance than Cu/Sn-5Sb/Cu. A previous study proved that the Cu/Sn5Sb-0.5Cu-0.1Ni-0.5Ag/Cu joint had better plasticity than Cu/Sn5Sb/Cu (Han et al, 2019a(Han et al, , 2019b(Han et al, , 2019c. Figure 1(c) is the shear distance-force of the joints, the plastic distance of Cu/Sn5Sb-0.5Cu-0.1Ni-0.5Ag/Cu was larger than that of Sn5Sb/Cu, and the force of Cu/Sn5Sb/Cu increased more sharply than Cu/Sn5Sb-0.5Cu-0.1Ni-0.5Ag/Cu (Han et al, 2019a(Han et al, , 2019b(Han et al, , 2019c.…”

“…A previous study proved that the Cu/Sn5Sb-0.5Cu-0.1Ni-0.5Ag/Cu joint had better plasticity than Cu/Sn5Sb/Cu (Han et al, 2019a(Han et al, , 2019b(Han et al, , 2019c. Figure 1(c) is the shear distance-force of the joints, the plastic distance of Cu/Sn5Sb-0.5Cu-0.1Ni-0.5Ag/Cu was larger than that of Sn5Sb/Cu, and the force of Cu/Sn5Sb/Cu increased more sharply than Cu/Sn5Sb-0.5Cu-0.1Ni-0.5Ag/Cu (Han et al, 2019a(Han et al, , 2019b(Han et al, , 2019c. In conclusion, the mechanical properties of Cu/Sn5Sb-0.5Cu-0.1Ni-0.5Ag/Cu, including the hardness, creep performance and plasticity, were much better than those of Cu/Sn-5Sb/Cu.…”

“…To narrow the research gap, a new low-cost lead-free solder alloy, Sn5Sb-0.5Cu-0.1Ni-0.5Ag, was obtained by adding Cu, Ni and Ag elements to the Sn5Sb matrix, which from previous studies, could be used in secondary reflow soldering processes such as double-sided circuit board SMT assembly (Han et al, 2019a(Han et al, , 2019b(Han et al, , 2019cLi et al, 2012;Hegde et al, 2009;Hammad, 2013). The alloy has the potential for application due to its better solderability than Sn5Sb.…”

Microstructure and properties of Sn-Ag and Sn-Sb lead-free solders in electronics packaging: a review

“…Adding trace elements or nanoparticles can further improve the solder joint performance. Han et al [69] studied the microstructure evolution of IMC in Au/ Sn-5Sb-1Cu-0.1Ni-0.1Ag/(Au)Ni solder joints. There Fig.…”

Electric current stressing enhanced damping properties in Sn5Sb solder

“…Sn5Sb has a higher melting temperature than the traditional Sn-Pb solders (Schon et al, 2019), making it suitable as interconnecting material for high-temperature applications in power electronics (Han et al, 2019;Han et al, 2020). In serving electronics, vibration is one of the major suffered mechanical loads, and vibration accounts for 20% failure of solder joints (An et al, 2018).…”