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Microstructural evolution of Cu–Sn–Ni compounds in full intermetallic micro-joint and in situ micro-bending test

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posted on 18.01.2019, 13:25 by Liping Mo, Chaowei Guo, Zheng Zhou, Fengshun Wu, Changqing LiuChangqing Liu
This study focuses on the microstructural evolution process of Cu–Sn–Ni intermetallic compounds (IMCs) interlayer in the micro-joints, formed from the initial Ni/Sn (1.5 µm)/Cu structure through transient liquid phase (TLP) soldering. Under the bonding temperature of 240 °C, the micro-joints evolve into Ni/(Cu, Ni)6Sn5/(Cu, Ni)3Sn/Cu structure, where the interfacial reactions on Cu/Sn and Sn/Ni are suppressed by the atoms diffusing from the opposite side. The thickness of (Cu, Ni)3Sn layer on plated Cu layer still increases with the prolonged dwell time. When the bonding temperature was elevated to 290 °C, the phase transformation of (Cu, Ni)6Sn5 into (Cu, Ni)3Sn has been accelerated, thus the majority of IMCs interlayer is constituted with (Cu, Ni)3Sn. However, a small amount of Ni-rich (Cu, Ni)6Sn5 phases still remain near the Ni substrate and some of them close to the center-line of IMCs interlayer. The state between (Cu, Ni)6Sn5 and the adjacent (Cu, Ni)3Sn tends to reach equilibrium in Ni content based on the observation from Transmission Electron Microscope (TEM). In addition, the Cu–Sn–Ni IMCs micro-cantilevers were fabricated from these micro-joints using Focus Ion Beam (FIB) for the in situ micro-bending test, the results indicate a high ultimate tensile strength as well as the brittle fracture in the inter- and transgranular modes.

Funding

This work was supported by the National Nature Science Foundation of China [NSFC No. 61574068] and the Fundamental Research Funds for the Central Universities [No. 2016JCTD112].

History

School

  • Mechanical, Electrical and Manufacturing Engineering

Published in

Journal of Materials Science: Materials in Electronics

Volume

29

Issue

14

Pages

11920 - 11929

Citation

MO, L. ... et al., 2018. Microstructural evolution of Cu–Sn–Ni compounds in full intermetallic micro-joint and in situ micro-bending test. Journal of Materials Science: Materials in Electronics, 29(14), pp. 11920 - 11929.

Publisher

© Springer Nature

Version

AM (Accepted Manuscript)

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/

Acceptance date

12/05/2018

Publication date

2018-05-22

Notes

This is a post-peer-review, pre-copyedit version of an article published in Journal of Materials Science: Materials in Electronics. The final authenticated version is available online at: https://doi.org/10.1007/s10854-018-9293-8

ISSN

0957-4522

eISSN

1573-482X

Language

en

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