Research of Wafer-Level Vacuum Packaging Based on TGV Technology for MEMS Devices

This paper reports a novel wafer-level vacuum packaging method based on TGV (Through Glass Via) technology for MEMS devices. For the first time, it is reported that the vacuum packaging is achieved by TGV scheme combined with triple anodic bonding (TGV substrate, MEMS structure and glass cap), which will bring more stable vacuum packaging, lower packaging stress and lower parasitic capacitance. As a crucial step, glass reflow process was analyzed theoretically and experimentally to improve the sealing performance of TGV substrate itself. And the CMP (Chemical Mechanical Polish) technology for TGV substrate, which polishes glass and silicon at the same time, was also researched and ameliorated to obtain a smooth surface for excellent strength of triple anodic bonding. Finally, a MEMS gyroscope was packaged without getter, and the packaged pressure was calibrated to be about 90Pa, demonstrating the feasibility of this packaging scheme.