Creep Behavior of Lead-Free Sn-Ag-Cu + Ni-Ge Solder Alloys

• Published in: Journal of electronic materials Vol. 38; no. 5; pp. 670 - 677
• Main Authors: Hidaka, N., Watanabe, H., Yoshiba, M.
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01.05.2009; Springer; Springer Nature B.V
• Subjects: Applied sciences; Brazing. Soldering; Characterization and Evaluation of Materials; Chemistry and Materials Science; Deformation; Electronics; Electronics and Microelectronics; Exact sciences and technology; Instrumentation; Joining, thermal cutting: metallurgical aspects; Lead free solders; Materials; Materials Science; Mechanical properties; Metals creep; Metals. Metallurgy; Microstructure; Optical and Electronic Materials; Solid State Physics; creep; microstructure; TH; Sn-Ag-Cu-Ni-Ge lead-free solders; Temperature dependence; Dislocation motion; Creep; Intermetallic compound; Tin alloy; Mechanical properties; Solder metal; Tin base alloys; Transmission electron microscopy; Creep fracture; Soldered joint; Lead free solder; Germanium; Copper; Microstructure; Creep deformation; Silver base alloys; Nickel alloy
• ISSN: 0361-5235; 1543-186X
• DOI: 10.1007/s11664-009-0689-3

We developed a new lead-free solder alloy, an Sn-Ag-Cu base to which a small amount of Ni and Ge is added, to improve the mechanical properties of solder alloys. We examined creep deformation in bulk and through-hole (TH)␣form for two lead-free solder alloys, Sn-3.5Ag-0.5Cu-Ni-Ge and Sn-3.0Ag-0.5Cu, at elevated temperatures, finding that the creep rupture life of the Sn-3.5Ag-0.5Cu-Ni-Ge solder alloy was over three times better than that of the Sn-3.0Ag-0.5Cu solder at 398 K. Adding Ni to the solder appears to make microstructural development finer and more uniform. The Ni added to the solder readily combined with Cu to form stable intermetallic compounds of (Cu, Ni) 6 Sn 5 capable of improving the creep behavior of solder alloys. Moreover, microstructural characterization based on transmission electron microscopy analyses observing creep behavior in detail showed that such particles in the Sn-3.5Ag-0.5Cu-Ni-Ge solder alloy prevent dislocation and movement.