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Numerical Analysis of the Thermal and Mechanical Performance of Cu Pillar Bumps During Reflow: Effects of Height and Solder Material

  • Topical Collection: Electronic Packaging and Interconnections 2023
  • Published:
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Abstract

This paper investigates the impact of various copper (Cu) pillar bump heights on temperature distribution, deformation and thermal stress during reflow. The virtual reflow oven environment was simulated using the fluid domain of the oven model. The accuracy of the fluid analysis was verified by comparing the obtained results with experimental data, which was conducted based on the Joint Electron Device Engineering Council (JEDEC) Standard. In addition, a grid independence test was carried out on the fluid mesh to determine the optimal mesh size for the simulations. A thermal fluid–structure interaction (FSI) approach was employed to couple the thermal results from the fluid analysis with the solid assembly. The results of the coupling analysis revealed that Cu pillar bumps with a height of 0.09 mm exhibited the lowest reflow temperature, minimal maximum deformation, and thermal stress, indicating that it is the optimal potential height for forming a good joint. The study also examines the impact of soldering materials, such as tin-bismuth (SnBi) and tin-silver-copper solder alloys (SAC305 and SAC405), on the Cu pillar bump. This study enables a comprehensive analysis of the thermal and mechanical performance of different Cu pillar bump parameters during the reflow process.

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Acknowledgments

The work is financially supported by the Ministry of Higher Education under Fundamental Research Grant Scheme, FRGS (Grant number FRGS/1/2020/TK0/USM/03/6). The authors would also like to thank Universiti Sains Malaysia and Western Digital Sdn. Bhd. for providing technical support.

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Authors and Affiliations

  1. School of Mechanical Engineering, Engineering Campus, Universiti Sains Malaysia, Nibong Tebal, Seberang Perai Selatan, 14300, Penang, Malaysia

    Jing Rou Lee, Mun Xi Chong & Mohd Sharizal Abdul Aziz

  2. Faculty of Mechanical Engineering & Technology, Universiti Malaysia Perlis, Perlis, Malaysia

    Chu Yee Khor

  3. Faculty of Chemical Engineering & Technology, Universiti Malaysia Perlis, Perlis, Malaysia

    Mohd Arif Anuar Mohd Salleh

  4. River Engineering and Urban Drainage Research Center (REDAC), Engineering Campus, Universiti Sains Malaysia, Nibong Tebal, Seberang Perai Selatan, 14300, Penang, Malaysia

    Mohd Remy Rozainy Mohd Arif Zainol

  5. Western Digital SanDisk Storage Malaysia Sdn. Bhd, Batu Kawan, Malaysia

    F. Che Ani

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  1. Jing Rou Lee
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Lee, J.R., Chong, M.X., Abdul Aziz, M.S. et al. Numerical Analysis of the Thermal and Mechanical Performance of Cu Pillar Bumps During Reflow: Effects of Height and Solder Material. J. Electron. Mater. 53, 1169–1182 (2024). https://doi.org/10.1007/s11664-023-10782-3

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