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

Abstract

Electronic devices need to work at high temperature in some fields for a long time, peculiarly step soldering technology, primary packaging and flip-chip connections, etc., along with the application of electronic products more and more widely. These phenomena promote the further development of hightemperature solders. Because of the high melting temperatures of Sn-Ag and Sn-Sb, they are suitable for high-temperature fields such as automotive electronics and avionics. In this review, the influences of trace elements and nanoparticles on microstructure, intermetallic components (IMC) growth, mechanical properties, wettability, melting behavior, and creep behavior of Sn-Ag and Sn-Sb solders have been summarized systematically. It was found that the addition of trace elements or nanoparticles into solders to be beneficial in improving the performance of Sn-Ag and Sn-Sb solders. Besides, the melting behavior of the solder at high temperatures can be further improved if Sn-Ag and Sn-Sb are used better as high-temperature solders.

Early wetting and interfacial behavior of Sn-based solder on copper substrates with different roughness

“…The development of lead-free products has become increasingly popular to protect the environment. In the lead-free process of electronic packaging, the solder is typically a eutectic tin-based alloy containing Ag, Cu and small amounts of other elements (Pan et al , 2008; Wang et al , 2021; Osório and Garcia, 2016; Gain et al , 2016; Yang et al , 2020). The poor performance of lead-free soldering processes, particularly in terms of wetting performance, as well as concerns about post-solder dependability, are critical issues that need to be addressed for large-scale industrial applications (Chen et al , 2018; Capela et al , 2023; Ismail et al , 2022).…”

In Situ Study the Grooving Effect Induced by Ag Particles on Rapid Growth of Cu6Sn5 Grain at Sn-xAg/Cu Soldering Interface during the Heat Preservation Stage

“…One of the notable reliability challenges in the context of lead-free Sn-based solder alloys is the formation of brittle intermetallic compounds (IMCs) [3][4][5][6][7][8]. The formation of Cu 6 Sn 5 IMCs in Sn/Cu, Sn-Ag/Cu, and Sn-Ag-Cu/Cu during reflow soldering is mainly governed by the grain boundary diffusion of Cu into the solder, and this is again influenced by the interfacial grain orientation or Ag 3 Sn nano-particles in cooling stage [2,[9][10][11][12][13]. Moreover, the solidified precipitated Ag 3 Sn phase is observed to only distribute on both sides of the groove boundary between adjacent grains, but not the entire grain surface from the SEM figures [2], from which can be inferred that Ag-free atoms are mainly distributed on the groove edges of the grains during the heat preservation stage.…”

The Effect of Micro-Alloying and Surface Finishes on the Thermal Cycling Reliability of Doped SAC Solder Alloys

“…To make matters even worse, the formation of the IMC layer is accelerated by the process of aging [ 5 , 6 ]. To minimize the adverse effects of aging, several elements, including bismuth (Bi), nickel (Ni), antimony (Sb), cobalt (Co), and indium (In), have been micro-alloyed with the SnAgCu (SAC)-based solder alloy [ 7 , 8 , 9 , 10 ]. Among several materials, SAC-based solder alloys have shown positive prospects.…”