Imaging the Polymorphic Transformation in a Single Cu₆Sn₅ Grain in a Solder Joint

Flora Somidin; Hiroshi Maeno; Xuan Quy Tran; Stuart D McDonald; Mohd Arif Anuar Mohd Salleh; Syo Matsumura; Kazuhiro Nogita

doi:10.3390/ma11112229

Imaging the Polymorphic Transformation in a Single Cu₆Sn₅ Grain in a Solder Joint

Materials (Basel). 2018 Nov 9;11(11):2229. doi: 10.3390/ma11112229.

Authors

Flora Somidin^{1

2}, Hiroshi Maeno³, Xuan Quy Tran⁴, Stuart D McDonald⁵, Mohd Arif Anuar Mohd Salleh⁶, Syo Matsumura^{7

8}, Kazuhiro Nogita⁹

Affiliations

¹ Nihon Superior Centre for the Manufacture of Electronic Materials (NS CMEM), School of Mechanical and Mining Engineering, The University of Queensland, Brisbane QLD 4072, Australia. f.somidin@uq.net.au.
² Centre of Excellence Geopolymer and Green Technology, School of Materials Engineering, Universiti Malaysia Perlis, Taman Muhibbah, Arau 02600, Malaysia. f.somidin@uq.net.au.
³ The Ultramicroscopy Research Center, Kyushu University, Fukuoka 819-0395, Japan. maeno@hvem.kyushu-u.ac.jp.
⁴ Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Fukuoka 819-0395, Japan. xuan.tran@nucl.kyushu-u.ac.jp.
⁵ Nihon Superior Centre for the Manufacture of Electronic Materials (NS CMEM), School of Mechanical and Mining Engineering, The University of Queensland, Brisbane QLD 4072, Australia. s.mcdonald1@uq.edu.au.
⁶ Centre of Excellence Geopolymer and Green Technology, School of Materials Engineering, Universiti Malaysia Perlis, Taman Muhibbah, Arau 02600, Malaysia. arifanuarsalleh@gmail.com.
⁷ The Ultramicroscopy Research Center, Kyushu University, Fukuoka 819-0395, Japan. syo@nucl.kyushu-u.ac.jp.
⁸ Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Fukuoka 819-0395, Japan. syo@nucl.kyushu-u.ac.jp.
⁹ Nihon Superior Centre for the Manufacture of Electronic Materials (NS CMEM), School of Mechanical and Mining Engineering, The University of Queensland, Brisbane QLD 4072, Australia. k.nogita@uq.edu.au.

Abstract

In-situ observations of the polymorphic transformation in a single targeted Cu₆Sn₅ grain constrained between Sn-0.7 wt % Cu solder and Cu-Cu₃Sn phases and the associated structural evolution during a solid-state thermal cycle were achieved via a high-voltage transmission electron microscope (HV-TEM) technique. Here, we show that the monoclinic η'-Cu₆Sn₅ superlattice reflections appear in the hexagonal η-Cu₆Sn₅ diffraction pattern upon cooling to isothermal 140 °C from 210 °C. The in-situ real space imaging shows that the η'-Cu₆Sn₅ contrast pattern is initiated at the grain boundary. This method demonstrates a new approach for further understanding the polymorphic transformation behavior on a real solder joint.

Keywords: Cu6Sn5 intermetallic compound; electron diffraction; high-voltage transmission electron microscopy; polymorphic phase transformation; time-temperature transformation.

Grants and funding

2016001895/University of Queensland-Nihon Superior