Microstructure, interfacial reactions and mechanical properties of Co/Sn/Co and Cu/Sn/Cu joints produced by transient liquid phase bonding

• Published in: Journal of materials science. Materials in electronics Vol. 29; no. 19; pp. 16388 - 16400
• Main Authors: Tian, Shuang, Zhou, Jian, Xue, Feng, Cao, Ruihua, Wang, Fengjiang
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.10.2018; Springer Nature B.V
• Subjects: Atomic structure; Bonded joints; Characterization and Evaluation of Materials; Chemical reactions; Chemistry and Materials Science; Copper; Diffusion; Elongation; Grain boundaries; Grain boundary diffusion; Interface reactions; Intermetallic compounds; Materials Science; Mechanical properties; Optical and Electronic Materials; Organic chemistry; Sandwich structures; Soldering; Substrates; Tensile tests; Tin; Transient liquid phase bonding; Wettability
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-018-9730-8

In this paper, the wettability and growth behaviors of interfacial intermetallic compounds (IMCs) in the Sn/Co and Sn/Cu liquid/solid couples were comparatively investigated. In situ tensile tests were conducted to evaluate the mechanical properties of the Co/Sn(IMCs)/Co and Cu/Sn(IMCs)/Cu joints. The wettability of Sn on Cu substrate was better than that of Co substrate. The lath-like CoSn 3 IMCs limited the improvement of wettability of Sn on Co substrate, even if the soldering temperature was increased. The Sn/Co couples showed an acceptable wettability for electronic application. During liquid aging, the rapid growing interfacial CoSn 3 were controlled by the combination of chemical reaction and atomic diffusion. Grain boundary diffusion should be responsible for the growth of Cu 6 Sn 5 in the Sn/Cu liquid/solid couples. The tensile strength and elongation of the Co/CoSn 3 /Co joints were basically equal to that of the Cu/IMCs/Cu full IMCs joints. Interfacial IMCs cracks were more likely to occur in the joints fabricated by Co substrate. The Co/CoSn 3 /Co sandwich structure can be fabricated within a remarkable short period of time at low temperature without pressure.