naa a22 4500 510804934 CHVBK 20180411083412.0 cr unu---uuuuu 180411e20130201xx s 000 0 eng 10.1007/s11664-012-2307-z doi (NATIONALLICENCE)springer-10.1007/s11664-012-2307-z Characterization of Recrystallization and Microstructure Evolution in Lead-Free Solder Joints Using EBSD and 3D-XRD [Elektronische Daten] [Bite Zhou, Thomas Bieler, Tae-Kyu Lee, Wenjun Liu] Development of vulnerable high-angle grain boundaries (and cracks) from low-angle boundaries during thermal cycling by means of continuous recrystallization was examined in fine-pitch ball grid array (BGA) packages with Sn-3.0Ag-0.5Cu (wt.%) (SAC305) lead-free solder joints. Electron backscatter diffraction (EBSD) and differential-aperture x-ray microscopy (DAXM or 3D-XRD) were used for surface and subsurface characterization. A large number of subgrain boundaries were observed in the parent orientation using both techniques. However, unlike studies of anisotropic deformation in noncubic metals at much lower homologous temperatures, no streaked diffraction peaks were observed in DAXM Laue patterns within each 1μm3 voxel after thermal cycling, suggesting that geometrically necessary dislocations (GNDs) are effectively absorbed by the preexisting subgrain boundaries. Storage at room temperature (0.6T m) prior to DAXM measurement may also facilitate recovery processes to reduce local GND contents. Heterogeneous residual elastic strains were found near the interface between a precipitated Cu6Sn5 particle and the Sn grain, as well as near particular subgrain boundaries in the parent orientation. Grain boundary migration associated with recrystallization resulted in regions without internal strains, subgrain boundaries, or orientation gradients. Development of new grain orientations by continuous recrystallization and subsequent primary recrystallization and grain growth occurred in the regions where the cracks developed. Orientation gradients and subgrain structure were observed within newly formed recrystallized grains that could be correlated with slip systems having high Schmid factors. TMS, 2012 Lead-free solder nationallicence Sn crystal orientation nationallicence recrystallization nationallicence EBSD nationallicence synchrotron 3D-XRD nationallicence strain nationallicence Zhou Bite Michigan State University, 48824, East Lansing, MI, USA aut Bieler Thomas Michigan State University, 48824, East Lansing, MI, USA aut Lee Tae-Kyu Cisco Systems, Inc., 96134, San Jose, CA, USA aut Liu Wenjun Advanced Photon Source, Argonne National Laboratory, 60439, Argonne, IL, USA aut Journal of Electronic Materials Springer US; http://www.springer-ny.com 42/2(2013-02-01), 319-331 0361-5235 42:2<319 2013 42 11664 https://doi.org/10.1007/s11664-012-2307-z text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11664-012-2307-z text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Zhou Bite Michigan State University, 48824, East Lansing, MI, USA aut NATIONALLICENCE 700 1- Bieler Thomas Michigan State University, 48824, East Lansing, MI, USA aut NATIONALLICENCE 700 1- Lee Tae-Kyu Cisco Systems, Inc., 96134, San Jose, CA, USA aut NATIONALLICENCE 700 1- Liu Wenjun Advanced Photon Source, Argonne National Laboratory, 60439, Argonne, IL, USA aut NATIONALLICENCE 773 0- Journal of Electronic Materials Springer US; http://www.springer-ny.com 42/2(2013-02-01), 319-331 0361-5235 42:2<319 2013 42 11664 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer