Recent progress on bumpless Cu/SiO2 hybrid bonding for 3D heterogeneous integration
Microelectronics International
ISSN: 1356-5362
Article publication date: 27 December 2022
Issue publication date: 17 March 2023
Abstract
Purpose
Bumpless Cu/SiO2 hybrid bonding, which this paper aims to, is a key technology of three-dimensional (3D) high-density integration to promote the integrated circuits industry’s continuous development, which achieves the stacks of chips vertically connected via through-silicon via. Surface-activated bonding (SAB) and thermal-compression bonding (TCB) are used, but both have some shortcomings. The SAB method is overdemanding in the bonding environment, and the TCB method requires a high temperature to remove copper oxide from surfaces, which increases the thermal budget and grossly damages the fine-pitch device.
Design/methodology/approach
In this review, methods to prevent and remove copper oxidation in the whole bonding process for a lower bonding temperature, such as wet treatment, plasma surface activation, nanotwinned copper and the metal passivation layer, are investigated.
Findings
The cooperative bonding method combining wet treatment and plasma activation shows outstanding technological superiority without the high cost and additional necessity of copper passivation in manufacture. Cu/SiO2 hybrid bonding has great potential to effectively enhance the integration density in future 3D packaging for artificial intelligence, the internet of things and other high-density chips.
Originality/value
To achieve heterogeneous bonding at a lower temperature, the SAB method, chemical treatment and the plasma-assisted bonding method (based on TCB) are used, and surface-enhanced measurements such as nanotwinned copper and the metal passivation layer are also applied to prevent surface copper oxide.
Keywords
Acknowledgements
The authors would like to thank the financial support from the National Natural Science Foundation of China (Grant No. 92164105 and 51975151), the Heilongjiang Provincial Natural Science Foundation of China under grant LH2019E041 and the Heilongjiang Touyan Innovation Team Program (HITTY-20190013).
Citation
Li, G., Kang, Q., Niu, F. and Wang, C. (2023), "Recent progress on bumpless Cu/SiO2 hybrid bonding for 3D heterogeneous integration", Microelectronics International, Vol. 40 No. 2, pp. 115-131. https://doi.org/10.1108/MI-07-2022-0121
Publisher
:Emerald Publishing Limited
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