|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||Advanced Microelectronic Packaging, Emerging Interconnection Technology, and Pb-free Solder
||Study of the Solid-State Diffusion of Bi in Sn – The Effects of β-Sn Grain Orientation
||Andre Delhaise, Zhangqi Chen, Doug Perovic
|On-Site Speaker (Planned)
Bismuth (Bi) is one of the more extensively studied alloying elements being considered for alloying lead-free solder alloys to improve microstructure, properties, and reliability. It has been established that Bi preserves the strength of the alloy after aging. Examination of microstructure reveals that strengthening occurs with homogenization of Bi in the tin (Sn) matrix via solid-state diffusion.
In this study, the effects of changes in Sn grain orientation on the diffusivity of Bi were analyzed. Sn was solidified slowly to produce coarse grains typical of grain morphologies in solder joints. Bi was subsequently sputtered onto the Sn, and samples underwent annealing at either 125oC or 100oC. Using compositional data collected from Electron Probe Microanalysis (EPMA), diffusivities were extracted for several orientations. Results show that the orientation of Sn has an influence on the diffusivity of Bi in Sn, with orientations closer to <100> yielding slightly higher diffusivities than those closer to <001>.
||Planned: Supplemental Proceedings volume