Investigation of the High-Vacuum Au/Si Eutectic Wafer Bonding Process for MEMS Resonators

作者：Kaixiang Zha, Shuo Wang, Junyuan Zhao, Bo Niu, Yiyi Hong, Yinfang Zhu, Jinling Yang · 发表于：Journal of Electronic Packaging · 年份：2025 · DOI：10.1115/1.4070514 · 被引用次数：1 · 研究领域：3D IC and TSV technologies、Advanced MEMS and NEMS Technologies、Electronic Packaging and Soldering Technologies

Abstract This study demonstrates a reliable wafer-level Au/Si eutectic bonding technique suitable for hermetic packaging of MEMS resonators with small cavities (≤0.01 mm3). By optimizing the Au-Si eutectic bonding process, including outgassing/bonding time, heating/cooling rates, and the incorporation of a Pt barrier layer, significant improvements in bonding quality were achieved. The hermetically sealed cavities exhibited a vacuum level below 2 Pa, a shear strength exceeding 56.4 MPa, and an average helium leak rate of 2.85 × 10−9 atm·cc/s. Furthermore, the quality factors (Q factors) of packaged cantilevers increased substantially from 400 to over 60,000, indicating effective mitigation of air damping. These results suggest that this bonding technique holds considerable promise for the development of high-performance, small-volume, and cost-effective MEMS devices.