Title
Solvent modulation, microstructure evaluation, process optimization, and nanoindentation analysis of micro-Cu@Ag core–shell sintering paste for power electronics packaging
Author
Chen, Haixue (Fudan University)
Wang, Xinyue (Fudan University)
Zeng, Zejun (Fudan University)
Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials) 
Zhang, Jing (Heraeus Materials Technology)
Liu, Pan (Fudan University; Research Institute of Fudan University, Ningbo)
Date
2023
Abstract
With the development of electronic technology towards high power, miniaturization, and system integration, power electronic packaging is facing increasing challenges, especially for die attachment. This research aims to explore silver-coated copper (Cu@Ag) paste with sufficient mechanical properties and high-temperature reliability, as an alternative solution for silver sintering with lower cost. Firstly, micro-Cu@Ag sintering pastes were investigated under four kinds of polyol-based solvent systems and two types of particle morphologies, which included sphere-type (SCu@Ag) and flake-type (FCu@Ag). Sintering performance and microstructural evolution were compared and analyzed. Notably, sintered joints employing the terpineol–polyethylene glycol solvent system and flake-type morphology displayed a denser microstructure in comparison to SCu@Ag joints. Its bonding strength reached 36.15 MPa, which was approximately 20% higher than SCu@Ag joints. Subsequently, the influence of key sintering process parameters on Cu@Ag joints was analyzed, including sintering temperature, pressure and time. Additionally, high-temperature aging and thermal cycling tests were conducted on the optimized Cu@Ag joints to assess their reliability. Finally, the micromechanical properties of Cu@Ag joints before and after high-temperature aging were further evaluated by nanoindentation including creep properties. The elastoplastic constitutive models of Cu@Ag sintered materials with different particle morphologies were constructed, providing valuable insights for reliability evaluation. The results indicated that FCu@Ag joints exhibited satisfactory creep resistance and high-temperature reliability. In conclusion, the FCu@Ag micro-paste based on the terpineol–polyethylene glycol solvent system proposed in this study demonstrated sufficient bonding strength, high reliability, and adequate mechanical properties as an attractive solution for high-temperature power electronics packaging.
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http://resolver.tudelft.nl/uuid:046880f9-39e1-44e3-8138-ffe45babfb8c
DOI
https://doi.org/10.1007/s10854-023-11083-5
Embargo date
2024-02-21
ISSN
0957-4522
Source
Journal of Materials Science: Materials in Electronics, 34 (24)
Bibliographical note
Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.
Part of collection
Institutional Repository
Document type
journal article
Rights
© 2023 Haixue Chen, Xinyue Wang, Zejun Zeng, Kouchi Zhang, Jing Zhang, Pan Liu