Early wetting and interfacial behavior of Sn-based solder on copper substrates with different roughness
Soldering & Surface Mount Technology
ISSN: 0954-0911
Article publication date: 12 September 2023
Issue publication date: 13 November 2023
Abstract
Purpose
This paper aims to investigate the effect of solder composition and roughness on early wetting behavior and interfacial reaction under atmospheric conditions.
Design/methodology/approach
High-speed photography is used to observe the early wetting and spreading process of the solder on the substrate in real time. The morphology of intermetallic compounds (IMCs) was observed by scanning electron microscopy, and the composition of IMCs micro bumps was determined by energy dispersive spectroscopy.
Findings
With a roughness range of 0.320–0.539 µm, the solder is distributed in an elliptical trilinear pattern along the grinding direction. With a roughness range of 0.029–0.031 µm, the solder spreads in the direction of grinding and perpendicular, forming a perfect circle (except in the case of Sn63Pb37 solder). The effect of three types of solder on early wettability is Sn63Pb37 > Sn96.5Ag3Cu0.5 > Sn. The wetting behavior is consistent with the Rn∼t model. The rapid spreading stage (Stage I) is controlled by the interfacial reaction with n1 values between 2.4 and 4. The slow spreading stage (stage II) is controlled by diffusion with n2 values between 4 and 6.7. The size of Cu6Sn5 formed on a rough substrate is greater than that produced on a smooth substrate.
Originality/value
Investigating the effect of solder composition and roughness on early wettability. This will provide a powerful guide in the field of soft brazing.
Keywords
Acknowledgements
This project is supported by National Natural Science Foundation of China (Grant No. 52375351) and Class III Peak Discipline of Shanghai-Materials Science and Engineering (High-Energy Beam Intelligent Processing and Green Manufacturing).
Conflicts of interest: The author(s) declared no potential conflicts of interest.
Citation
Han, Y., Chen, J., Zhang, S. and Yu, Z. (2023), "Early wetting and interfacial behavior of Sn-based solder on copper substrates with different roughness", Soldering & Surface Mount Technology, Vol. 35 No. 5, pp. 331-343. https://doi.org/10.1108/SSMT-07-2023-0041
Publisher
:Emerald Publishing Limited
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