pp. 2889-2895
S&M1726 Research Paper of Special Issue https://doi.org/10.18494/SAM.2018.1948 Published in advance: August 21, 2018 Published: December 18, 2018 Stress-enhanced Cu-to-Cu Bonding for MEMS Packaging [PDF] Jenn-Ming Song, Sin-Yong Liang, Zong-Yu Xie, Po-Hao Chiang, Shang-Kun Huang, Ying-Ta Chiu, David Tarng, Chih-Pin Hung, and Jing-Yuan Lin (Received April 2, 2018; Accepted June 15, 2018) Keywords: MEMS packaging, Cu-to-Cu bonding, air plasma bombardment, formic acid vapor
To replace Al–Ge eutectic bonding, low-temperature direct Cu-to-Cu bonding was developed in this study. Lattice distortion and thus a hardened Cu subsurface conducted by air plasma bombardment, instead of surface activation, contributed to a compressive residual stress component and an accelerated Cu atom diffusion. This gave rise to a significant improvement in direct Cu bonding strength. Subjected to 3-min plasma exposure and the following deoxidation treatment using catalyzed formic acid vapor, robust Cu-to-Cu bonding with the joint strength up to 31.7 MPa can be achieved when bonded at 250 ℃ for 5 min under a loading pressure of 10 MPa in N2.
Corresponding author: Jenn-Ming SongCite this article Jenn-Ming Song, Sin-Yong Liang, Zong-Yu Xie, Po-Hao Chiang, Shang-Kun Huang, Ying-Ta Chiu, David Tarng, Chih-Pin Hung, and Jing-Yuan Lin, Stress-enhanced Cu-to-Cu Bonding for MEMS Packaging, Sens. Mater., Vol. 30, No. 12, 2018, p. 2889-2895. |