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Microstructure and growth of Cu hillock on redistribution line under electromigration

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Abstract

The formation of hillock at the anode side of a circuit under electromigration is detrimental to electrical performance and electronic reliability. The study presented a detailed investigation of the microstructure of Cu hillock formed on 2 μm x 3 μm Cu redistribution line under high electrical current density 1.44 × 107 A/cm2. The electron backscatter diffraction analysis revealed that the microstructure of the Cu redistribution line remain intact after 162 min current stressing. High-resolution transmission electron microscope analysis showed that the dome shape Cu hillock formed is polycrystalline with amorphous inclusion and twin structure. A mechanism considering radial surface diffusion of Cu atoms was proposed to illustrate the growth of dome shape Cu hillock under electromigration.

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Acknowledgements

The authors thank the partial financial support of this study from the Ministry of Science and Technology of Republic of China under MOST 110-2221-E-006 -130 -MY2 is gratefully appreciated. The TEM analysis conducted by the Core Facility Center of National Cheng Kung University is also appreciated.

Funding

The financial support of this study is from Ministry of Science and Technology of Republic of China under MOST 110-2221-E-006-130-MY2.

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Authors and Affiliations

  1. Department of Materials Science and Engineering, National Cheng Kung University, Tainan, Taiwan

    Yen-Cheng Huang & Kwang-Lung Lin

  2. Product Characterization Division, CRD, ASE Group, Kaohsiung City, Taiwan

    Min-Yan Tsai, Ting-Chun Lin & Yung-Sheng Lin

  3. CRD, ASE Group, Kaohsiung City, Taiwan

    Chi-Pin Hung

Authors
  1. Yen-Cheng Huang
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  2. Min-Yan Tsai
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  4. Yung-Sheng Lin
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  6. Kwang-Lung Lin
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Contributions

YCH carried out FIB and TEM analysis, Min-Yan Tsai conducted specimen design and resistance measurement during electromigration experiments, TCL conducted the EBSD and in situ SEM investigations of electromigration experiments, YSL provided experimental supports to acquire the Cu redistribution line, CPH was the project manager, KLL received funding grant from the Ministry of Science and Technology-Taiwan and designed the experimental work also wrote the original draft of the manuscript.

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Correspondence to Kwang-Lung Lin.

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Huang, YC., Tsai, MY., Lin, TC. et al. Microstructure and growth of Cu hillock on redistribution line under electromigration. J Mater Sci: Mater Electron 35, 659 (2024). https://doi.org/10.1007/s10854-024-12407-9

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