Abstract
The microstructure of Sn-Ag-Cu (SAC) solder joints plays an important role in the reliability of electronics, and interlaced twinning has been linked with improved performance. Here, we study the three-dimensional (3-D) shape of interlaced regions in Sn-3.0Ag-0.5Cu (SAC305) solder balls by combining serial sectioning with electron backscatter diffraction. In solder balls without large Ag3Sn plates, we show that the interlaced volume can be reasonably approximated as a hollow double cone with the common 〈100〉 twinning axis as the cone axis, and the 〈110〉 from all three twinned orientations making up the cone sides. This 3-D morphology can explain a range of partially interlaced morphologies in past work on 2-D cross-sections.
Highlights
BSn is the main solid phase in most electronic solder joints,[1] and dictates much of the electrical and mechanical properties of joints
This study aims to build a deeper understanding of the formation of interlaced twinning in SAC solders by exploring the crescent and ring microstructures of bSn interlacing in Sn-3.0Ag0.5Cu (SAC305) solder balls
We focus on reconstructing the 3-D shape of interlaced regions by combining serial sectioning and Electron backscatter diffraction (EBSD)
Summary
BSn is the main solid phase in most electronic solder joints,[1] and dictates much of the electrical and mechanical properties of joints. The three orientations of bSn are related via cyclic twinning around a common h100i direction,[1,6] and seem to come from a single nucleation event. These cyclic twin microstructures have been reported as either a beach-ball or interlacing morphology, or a mixture of the two.[9,12] Electron backscatter diffraction (EBSD) techniques have been successfully used to identify crystal orientations and relationships (Received July 16, 2020; accepted September 21, 2020; published online October 15, 2020)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
