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Cu-Cu joint with Sn-58Bi/Porous Cu/Sn-58Bi transient liquid phase bonding under formic acid atmosphere

Bifu Xiong (Key Laboratory of Microelectronic Packaging and Assembly Technology of Guangxi Education, School of Mechanical and Electrical Engineering, Guilin University of Electronic Technology, Guilin, China)
Siliang He (Key Laboratory of Microelectronic Packaging and Assembly Technology of Guangxi Education, School of Mechanical and Electrical Engineering, Guilin University of Electronic Technology, Guilin, China and Institute of Semiconductors, Guangdong Academy of Sciences, Guangzhou, China) *
Jinguo Ge (Key Laboratory of Microelectronic Packaging and Assembly Technology of Guangxi Education, School of Mechanical and Electrical Engineering, Guilin University of Electronic Technology, Guilin, China)
Quantong Li (Institute of Semiconductors, Guangdong Academy of Sciences, Guangzhou, China)
Chuan Hu (Institute of Semiconductors, Guangdong Academy of Sciences, Guangzhou, China)
Haidong Yan (College of Electrical Engineering, Zhejiang University, Hangzhou, China)
Yu-An Shen (Department of Materials Science and Engineering, Feng Chia University, Taichung, Taiwan)

Soldering & Surface Mount Technology

ISSN: 0954-0911

Article publication date: 13 September 2023

Issue publication date: 10 January 2024

132

Abstract

Purpose

This paper aims to examine the effects of bonding temperature, bonding time, bonding pressure and the presence of a Pt catalyst on the bonding strength of Cu/SB/P-Cu/SB/Cu joints by transient liquid phase bonding (TLPB).

Design/methodology/approach

TLPB is promising to assemble die-attaching packaging for power devices. In this study, porous Cu (P-Cu) foil with a distinctive porous structure and Sn-58Bi solder (SB) serve as the bonding materials for TLPB under a formic acid atmosphere (FA). The high surface area of P-Cu enables efficient diffusion of the liquid phase of SB, stimulating the wetting, spreading and formation of intermetallic compounds (IMCs).

Findings

The higher bonding temperature decreased strength due to the coarsening of IMCs. The longer bonding time reduced the bonding strength owing to the coarsened Bi and thickened IMC. Applying optimal bonding pressure improved bonding strength, whereas excessive pressure caused damage. The presence of a Pt catalyst enhanced bonding efficiency and strength by facilitating reduction–oxidation reactions and oxide film removal.

Originality/value

Overall, this study demonstrates the feasibility of low-temperature TLPB for Cu/SB/P-Cu/SB/Cu joints and provides insights into optimizing bonding strength for the interconnecting materials in the applications of power devices.

Keywords

Acknowledgements

This work was supported by Science and Technology Planning Project of Guangxi (Grant No. GuiKe AD20297022), Guangxi Natural Science Foundation (No. 2021GXNSFBA075027), China Postdoctoral Science Foundation (Grant No. 2021M700887), Key-Area Research and Development Program of Guangdong Province (Grant No. 2020B0101320001), GDAS’ Project of Science and Technology Development (Grant No. 2022GDASZH-2022010111, No. 2021GDASYL-20210103074), Guangxi Key Laboratory of Manufacturing System & Advanced Manufacturing Technology (Grant No. 20-065-40-003Z), and Innovation Project of GUET Graduate Education (Grant No. 2023YCXS001). Yu-An Shen thanks National Science and Technology Council of Taiwan under Project NSTC 112-2221-E-035-022 and 111-2221-E-035-054.

Citation

Xiong, B., He, S., Ge, J., Li, Q., Hu, C., Yan, H. and Shen, Y.-A. (2024), "Cu-Cu joint with Sn-58Bi/Porous Cu/Sn-58Bi transient liquid phase bonding under formic acid atmosphere", Soldering & Surface Mount Technology, Vol. 36 No. 1, pp. 39-50. https://doi.org/10.1108/SSMT-07-2023-0034

Publisher

:

Emerald Publishing Limited

Copyright © 2023, Emerald Publishing Limited

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