Au-Ge based Candidate Alloys for High-Temperature Lead-Free Solder Alternatives

Vivek Chidambaram, John Hald, Jesper Henri Hattel

Research output: Chapter in Book/Report/Conference proceedingArticle in proceedingsResearch


Au-Ge based candidate alloys have been proposed as an alternative to high-lead content solders that are currently being used for high-temperature applications. The influence of the low melting point metals namely In, Sb and Sn to the Au-Ge eutectic with respect to the microstructure and microhardness has been extensively reported. Furthermore, the effects of thermal aging on the microstructure and its corresponding microhardness of these promising candidate alloys have been investigated in this work. After thermal aging at 200°C for different durations ranging from 1 day to 3 weeks, the microstructure varied a lot in morphology in the case of both Au-Ge-Sb and Au-Ge-Sn candidate alloys. Surprisingly, the microstructure remained relatively stable even after long term thermal aging in the case of Au-Ge-In candidate alloy. The microhardness measurement is well correlated with the solubility and reactivity of these alloying elements, characteristics of their intermetallic compounds (IMCs) and the distribution of phases. The primary strengthening mechanism in the case of Au-Ge-In and Au-Ge-Sn combinations was determined to be the classic solute atom strengthening. The Au-Ge-Sb combination was primarily strengthened by the refined (Ge) dispersed phase. The distribution of phases played a relatively more crucial role in determining the ductility of the bulk solder alloy. In the present work it was found that among the low melting point metals, the addition of Sb to the Au-Ge eutectic would not only decrease its melting point but also would improve its ductility substantially.
Original languageEnglish
Title of host publication2009 International Symposium on Microelectronics
PublisherInternational Microelectronics and packaging Society
Publication date2009
Publication statusPublished - 2009
Event42nd International Symposium on Microelectronics: Bringing Together The Entire Microelectronics Supply Chain! - San Jose, United States
Duration: 1 Nov 20095 Nov 2009
Conference number: 42


Conference42nd International Symposium on Microelectronics
Country/TerritoryUnited States
CitySan Jose


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