A Wafer-Level Fabricated Heating-Vacuum Micro-Platform with Resonant MEMS Monolithically Integrated

This paper presents a silicon-based wafer-level vacuum packaging platform with a monolithically integrated micro-oven. This system provides vacuum and constant temperature operating conditions to improve the performance of resonant micro-electro-mechanical systems (MEMS) devices. Based on a three-layer wafer-level vacuum packaging process, the platform integrates a silicon thermistor, a thermal isolation structure, and a heater with the addition of a mask and an additional silicon wafer. This wafer-level vacuum-packaging platform achieved a vacuum level of approximately 6 mTorr. Due to the micro-oven, the temperature coefficient of the resonant frequency for the MEMS resonator was reduced by 48 times, and the temperature coefficient of the quality factor was reduced 19 times within the temperature range of -40 °C to 80 °C. The heater of the micro-oven consumed about 364 mW of power when the ambient temperature was -40 °C and the temperature controlled by the micro-oven was 100 °C. This method enables the wafer-level integration of the thermistor, thermal isolation structure, heater, and vacuum-packaged resonator, offering advantages such as low cost, efficient batch production, and high performance.