Multiscale microstructural characterization of Sn-rich alloys by three dimensional (3D) X-ray synchrotron tomography and focused ion beam (FIB) tomography

• Published in: Materials characterization Vol. 70; no. Complete; pp. 33 - 41
• Main Authors: Yazzie, K.E., Williams, J.J., Phillips, N.C., De Carlo, F., Chawla, N.
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.08.2012; Elsevier
• Subjects: 3D materials science; Alloys; Applied sciences; Brazing. Soldering; COPPER ALLOYS; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Focused ion beam tomography; INTERMETALLIC COMPOUNDS; ION BEAMS; Joining, thermal cutting: metallurgical aspects; LAMELLAE; LEAD ALLOYS; MATERIALS SCIENCE; Metals. Metallurgy; MICROSTRUCTURE; MORPHOLOGY; PARTICLE SIZE; Pb-free solder; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; PHOTON COMPUTED TOMOGRAPHY; Physics; Precipitates; PRECIPITATION; SOLDERED JOINTS; Solidification; SPATIAL DISTRIBUTION; Statistics; SYNCHROTRON RADIATION; Three dimensional; Tin; TIN BASE ALLOYS; Tomography; X RADIATION; X-ray tomography; X-rays; 3D materials science; Focused ion beam tomography; X-ray tomography; Pb-free solder; Solder; Ion beam; Microstructure; Soldering
• ISSN: 1044-5803; 1873-4189
• DOI: 10.1016/j.matchar.2012.05.004

Sn-rich (Pb-free) alloys serve as electrical and mechanical interconnects in electronic packaging. It is critical to quantify the microstructures of Sn-rich alloys to obtain a fundamental understanding of their properties. In this work, the intermetallic precipitates in Sn–3.5Ag and Sn–0.7Cu, and globular lamellae in Sn–37Pb solder joints were visualized and quantified using 3D X-ray synchrotron tomography and focused ion beam (FIB) tomography. 3D reconstructions were analyzed to extract statistics on particle size and spatial distribution. In the Sn–Pb alloy the interconnectivity of Sn-rich and Pb-rich constituents was quantified. It will be shown that multiscale characterization using 3D X-ray and FIB tomography enabled the characterization of the complex morphology, distribution, and statistics of precipitates and contiguous phases over a range of length scales. ► Multiscale characterization by X-ray synchrotron and focused ion beam tomography. ► Characterized microstructural features in several Sn-based alloys. ► Quantified size, fraction, and clustering of microstructural features.