Hermeticity of eutectic bond layers for sensor packages on wafer-level

In MEMS industry there is a high demand for reliable hermetic wafer-level encapsulation. This paper presents a methodology to monitor the pressure inside a package after the wafer-level bonding process. Therefore, novel micro-electro-mechanical resonators designed as double ended tuning forks (DETFs) were built to measure the quality factor Q as a function of the inside cavity pressure. Obtained experimental results clearly verified the feasibility of the developed MEMS structures, providing a simple method to evaluate the hermeticity of wafer bonding technologies.