About this Abstract |
| Meeting |
2027 TMS Annual Meeting & Exhibition
|
| Symposium
|
Electronic Packaging and Interconnection Materials IV
|
| Presentation Title |
Microstructure evolution and crack propagation in Sn-Ag-Cu-Bi solder joints during harsh thermal cycling |
| Author(s) |
Christopher M. Gourlay, Chen-Lin Hsieh, Richard J. Coyle |
| On-Site Speaker (Planned) |
Christopher M. Gourlay |
| Abstract Scope |
Solder alloys for high performance and high-value applications often add bismuth to Sn–Ag–Cu-based compositions. Bismuth increases strength and can improve solder joint reliability, but thermal cycling tests have shown variable thermal fatigue performance. To better understand the thermal fatigue mechanisms, we investigate a range of Sn–Ag–Cu-Bi solder alloys containing between 3 and 6 wt.% Bi in two types of ball grid array (BGA) package tested using a harsh ATC profile of -55/125 °C. We study how the Bi affects the solder microstructure after soldering, after multi-year storage at room temperature and after thermal cycling, with a focus on precipitation, microstructure stability and how the in-service microstructure evolves from the as-soldered microstructure. We next explore the correlation between Weibull reliability statistics, changes in the fatigue crack path and the amount of energy stored in the tin phase after thermal cycling to gain insights into the differences in performance. |
| Proceedings Inclusion? |
Planned: TMS Journal: Journal of Electronic Materials |
| Keywords |
Electronic Materials, Phase Transformations, Joining |