Low-Temperature Cu/SiO2 Hybrid Bonding with Low Contact Resistance Using (111)-Oriented Cu Surfaces

Jia-Juen Ong; Wei-Lan Chiu; Ou-Hsiang Lee; Chia-Wen Chiang; Hsiang-Hung Chang; Chin-Hung Wang; Kai-Cheng Shie; Shih-Chi Yang; Dinh-Phuc Tran; King-Ning Tu; Chih Chen

doi:10.3390/ma15051888

Low-Temperature Cu/SiO₂ Hybrid Bonding with Low Contact Resistance Using (111)-Oriented Cu Surfaces

Materials (Basel). 2022 Mar 3;15(5):1888. doi: 10.3390/ma15051888.

Authors

Jia-Juen Ong^{1

2}, Wei-Lan Chiu³, Ou-Hsiang Lee³, Chia-Wen Chiang³, Hsiang-Hung Chang³, Chin-Hung Wang³, Kai-Cheng Shie^{1

2}, Shih-Chi Yang^{1

2}, Dinh-Phuc Tran^{1

2}, King-Ning Tu^{4

5}, Chih Chen^{1

2}

Affiliations

¹ Department of Materials Science and Engineering, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan.
² Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan.
³ Electronic and Optoelectronic System Research Laboratories, Industrial Technology Research Institute (ITRI), Hsinchu 30010, Taiwan.
⁴ Department of Materials Science and Engineering, City University of Hong Kong, Hong Kong, China.
⁵ Department of Electrical Engineering, City University of Hong Kong, Hong Kong, China.

Abstract

We adopted (111)-oriented Cu with high surface diffusivity to achieve low-temperature and low-pressure Cu/SiO₂ hybrid bonding. Electroplating was employed to fabricate arrays of Cu vias with 78% (111) surface grains. The bonding temperature can be lowered to 200 °C, and the pressure is as low as 1.06 MPa. The bonding process can be accomplished by a 12-inch wafer-to-wafer scheme. The measured specific contact resistance is 1.2 × 10^-9 Ω·cm², which is the lowest value reported in related literature for Cu-Cu joints bonded below 300 °C. The joints possess excellent thermal stability up to 375 °C. The bonding mechanism is also presented to provide more understanding on hybrid bonding.

Keywords: Cu/SiO2 hybrid bonding; highly (111)-nanotwinned Cu; low temperature bonding; microelectronic packaging.

Abstract

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