Cu/Sn Isothermal Solidification Technology for Hermetic Packaging of MEMS

This paper introduces a novel wafer-level hermetic packaging technology for MEMS based on Cu/Sn isothermal solidification (IS) technology. We designed the structure of the intermediate multilayer and the pattern of sealing rings, optimized the bonding process, and analyzed some key factors affecting the hermeticity, such as the dimension of the sealing rings. Successful Cu/Sn IS bonding was realized at a low bonding temperature of 350degC under the optimal conditions. High shear strength of 27.7 MPa and excellent leak rate of around 2times10^-9 atm cc/s have been achieved, which meet the requirements of MIL-STD-883E. Finally we designed and manufactured the micro resonator based on the Cu/Sn IS technology