Low-Temperature Transient Liquid Phase Bonding Technology via Cu Porous-Sn58Bi Solid–Liquid System under Formic Acid Atmosphere

Siliang He; Bifu Xiong; Fangyi Xu; Biyang Chen; Yinhua Cui; Chuan Hu; Gao Yue; Yu-An Shen

doi:10.3390/ma16062389

Materials (Mar 2023)

Low-Temperature Transient Liquid Phase Bonding Technology via Cu Porous-Sn58Bi Solid–Liquid System under Formic Acid Atmosphere

Siliang He,
Bifu Xiong,
Fangyi Xu,
Biyang Chen,
Yinhua Cui,
Chuan Hu,
Gao Yue,
Yu-An Shen

Affiliations

Siliang He: Guangxi Education Department Key Laboratory of Microelectronic Packaging & Assembly Technology, School of Mechanical & Electrical Engineering, Guilin University of Electronic Technology, Guilin 541004, China
Bifu Xiong: Guangxi Education Department Key Laboratory of Microelectronic Packaging & Assembly Technology, School of Mechanical & Electrical Engineering, Guilin University of Electronic Technology, Guilin 541004, China
Fangyi Xu: Guangxi Education Department Key Laboratory of Microelectronic Packaging & Assembly Technology, School of Mechanical & Electrical Engineering, Guilin University of Electronic Technology, Guilin 541004, China
Biyang Chen: Guangxi Education Department Key Laboratory of Microelectronic Packaging & Assembly Technology, School of Mechanical & Electrical Engineering, Guilin University of Electronic Technology, Guilin 541004, China
Yinhua Cui: Institute of Semiconductors, Guangdong Academy of Sciences, Guangzhou 510650, China
Chuan Hu: Institute of Semiconductors, Guangdong Academy of Sciences, Guangzhou 510650, China
Gao Yue: Guangxi Education Department Key Laboratory of Microelectronic Packaging & Assembly Technology, School of Mechanical & Electrical Engineering, Guilin University of Electronic Technology, Guilin 541004, China
Yu-An Shen: Department of Materials Science and Engineering, Feng Chia University, Taichung 407, Taiwan

DOI: https://doi.org/10.3390/ma16062389
Journal volume & issue: Vol. 16, no. 6
p. 2389

Abstract

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This study proposes a low-temperature transient liquid phase bonding (TLPB) method using Sn58Bi/porous Cu/Sn58Bi to enable efficient power-device packaging at high temperatures. The bonding mechanism is attributed to the rapid reaction between porous Cu and Sn58Bi solder, leading to the formation of intermetallic compounds with high melting point at low temperatures. The present paper investigates the effects of bonding atmosphere, bonding time, and external pressure on the shear strength of metal joints. Under formic acid (FA) atmosphere, Cu6Sn5 forms at the porous Cu foil/Sn58Bi interface, and some of it transforms into Cu3Sn. External pressure significantly reduces the micropores and thickness of the joint interconnection layer, resulting in a ductile fracture failure mode. The metal joint obtained under a pressure of 10 MPa at 250 °C for 5 min exhibits outstanding bonding mechanical performance with a shear strength of 62.2 MPa.

Published in Materials

ISSN: 1996-1944 (Online)
Publisher: MDPI AG
Country of publisher: Switzerland
LCC subjects: Technology: Electrical engineering. Electronics. Nuclear engineering; Technology: Engineering (General). Civil engineering (General); Science: Natural history (General): Microscopy; Science: Physics: Descriptive and experimental mechanics
Website: http://www.mdpi.com/journal/materials/

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