Hybrid Cu-to-Cu bonding with nano-twinned Cu and non-conductive paste

Yu-Hao Kuo; Dinh-Phuc Tran; Jia-Juen Ong; K.N. Tu; Chih Chen

Journal of Materials Research and Technology (May 2022)

Hybrid Cu-to-Cu bonding with nano-twinned Cu and non-conductive paste

Yu-Hao Kuo,
Dinh-Phuc Tran,
Jia-Juen Ong,
K.N. Tu,
Chih Chen

Affiliations

Yu-Hao Kuo: Department of Materials Science and Engineering, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan; Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu, 30010, Taiwan
Dinh-Phuc Tran: Department of Materials Science and Engineering, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan; Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu, 30010, Taiwan
Jia-Juen Ong: Department of Materials Science and Engineering, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan; Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu, 30010, Taiwan
K.N. Tu: Department of Materials Science and Engineering and Department of Electrical Engineering, City University of Hong Kong, Kowloon, Hong Kong
Chih Chen: Department of Materials Science and Engineering, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan; Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu, 30010, Taiwan; Corresponding author.

Journal volume & issue: Vol. 18
pp. 859 – 871

Abstract

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Highly (111)-oriented nanotwinned copper (nt-Cu) and non-conductive paste (NCP) were employed to fabricate hybrid Cu–Cu bonding. We tailored and correlated the fracture modes, bonding strengths, and microstructures of the joints. A non-flow underfilling process was performed, and low temperature bonding was achieved in a single heat treatment at 180 °C for 120 min without vacuum. We found that under a post-annealing treatment, recrystallization and grain growth occurred. The bonding interfaces were partially removed and the joints were further strengthened. The fracture modes of the hybrid bonding structure were characterized using pull tests and correlated with their bonding properties. Such hybrid Cu–Cu microbumps with high bonding strength and low thermal budget can be widely used for advanced ultra-fine-pitch packaging.

Published in Journal of Materials Research and Technology

ISSN: 2238-7854 (Print); 2214-0697 (Online)
Publisher: Elsevier
Country of publisher: Netherlands
LCC subjects: Technology: Mining engineering. Metallurgy
Website: https://www.journals.elsevier.com/journal-of-materials-research-and-technology/

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