Effect of porous Cu addition on the microstructure and mechanical properties of SnBi-xAg solder joints

Journal article (2020)

Authors

Yang Liu Yangzhou University
Boqiao Ren Yangzhou University, Harbin University of Science and Technology
Min Zhou Yangzhou University
Yuxiong Xue Yangzhou University
Xianghua Zeng Yangzhou University
Fenglian Sun Harbin University of Science and Technology
Xuejun Fan Lamar University
Kouchi Zhang Electronic Components, Technology and Materials - EEMCS
Research Group
Electronic Components, Technology and Materials (EEMCS) (TU Delft)
Microstructure Hardness Shear behavior Porous Cu SnBi
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Published Date

2020

Language

English

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Faculty

Electrical Engineering, Mathematics and Computer Science

Department

Microelectronics

Research Group

Electronic Components, Technology and Materials

Abstract

The effects of porous copper (P-Cu) on the microstructure, hardness, and shear strength of SnBi, SnBi-0.4Ag, and SnBi-1Ag solder joints were investigated in this paper. The experimental results show that P-Cu frames distribute in the solder bulks and form triangular areas. The addition of P-Cu leads to the microstructural refinement in the enclosed areas by the P-Cu frames in the solder bulks. The average hardness here is increased due to the fine grain strengthening mechanism. The SnBi-1Ag@P-Cu solder bulk shows smaller Bi-rich grains but larger β-Sn dendrites than the other two P-Cu-enhanced solder bulks. Porous Cu exists as a frame structure in the solder joints, which hinders the initiation and propagation of cracks and has a positive effect on the improvement of joint strength. Compared to the SnBi and SnBiAg solder joints, the shear strength of the P-Cu-enhanced solder joints is increased by 15%. The average shear strength of the SnBi-0.4Ag@P-Cu solder joint is 79.34 MPa, which is the highest among all the solder joints investigated in this study.