The preparation and wettability of the Sn-9Zn-2.5Bi-1.5In solder paste for SMT process and high shear ball performance
Abstract
Purpose
This study aims to focus on the surface mount technology (SMT) mass production process of Sn-9Zn-2.5Bi-1.5In solder. It explores it with some components that will provide theoretical support for the industrial SMT application of Sn-Zn solder.
Design/methodology/approach
This study evaluates the properties of solder pastes and selects a more appropriate reflow parameter by comparing the microstructure of solder joints with different reflow soldering profile parameters. The aim is to provide an economical and reliable process for SMT production in the industry.
Findings
Solder paste wettability and solder ball testing in a nitrogen environment with an oxygen content of 3,000 ppm meet the requirements of industrial production. The printing performance of the solder paste is good and can achieve a printing rate of 100–160 mm/s. When soldering with a traditional stepped reflow soldering profile, air bubbles are generated on the surface of the solder joint, and there are many voids and defects in the solder joint. A linear reflow soldering profile reduces the residence time below the melting point of the solder paste (approximately 110 s). This reduces the time the zinc is oxidized, reducing solder joint defects. The joint strength of tin-zinc joints soldered with the optimized reflow parameters is close to that of Sn-58Bi and SAC305, with high joint strength.
Originality/value
This study attempts to industrialize the application of Sn-Zn solder and solves the problem that Sn-Zn solder paste is prone to be oxidized in the application and obtains the SMT process parameters suitable for Sn-9Zn-2.5Bi-1.5In solder.
Keywords
Acknowledgements
The authors acknowledge the financial support from the opening fund of the Key Laboratory of Science and Technology on Silicon Devices, Chinese Academy of Sciences (KLSDTJJ2022-5), the Chongqing Natural Science Foundation of China (cstc2021jcyj-msxmX1002) and the opening fund of State Key Laboratory for Mechanical Behavior of Materials (202325012).
Citation
Li, B., Qu, S. and Zhang, G. (2024), "The preparation and wettability of the Sn-9Zn-2.5Bi-1.5In solder paste for SMT process and high shear ball performance", Soldering & Surface Mount Technology, Vol. ahead-of-print No. ahead-of-print. https://doi.org/10.1108/SSMT-02-2024-0006
Publisher
:Emerald Publishing Limited
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