Title :
A novel fabrication and wafer level hermetic sealing method for SOI-MEMS devices using SOI cap wafers
Author :
Torunbalci, Mustafa Mert ; Alper, Said Emre ; Akin, Tayfun
Author_Institution :
MEMS Res. & Applic. Center, Middle East Tech. Univ., Ankara, Turkey
Abstract :
This paper presents a novel and inherently simple all-silicon fabrication and hermetic packaging method developed for SOI-MEMS devices, enabling lead transfer using vertical feedthroughs formed on an SOI cap wafer. The processes of the SOI cap wafer and the SOI-MEMS wafer require a total of five inherently-simple mask steps, providing a combined process and packaging yield as high as 95%. The hermetic encapsulation is achieved by Au-Si eutectic bonding at 400°C. The package pressure is measured as 1 Torr without any getter activation, and the package is proved to remain hermetic even after various temperature cycling tests. The shear strength of the fabricated chips is measured to be above 15 MPa, indicating a mechanically strong bonding.
Keywords :
elemental semiconductors; encapsulation; gold; hermetic seals; micromechanical devices; shear strength; silicon; silicon-on-insulator; wafer bonding; wafer level packaging; Au-Si; MEMS devices; SOI cap wafers; all-lead transfer; all-silicon fabrication; eutectic bonding; hermetic encapsulation; mask steps; packaging yield; process yield; temperature 41 degC; temperature cycling tests; vertical feedthroughs; wafer level hermetic sealing method; Bonding; Cavity resonators; Encapsulation; Micromechanical devices; Q-factor;
Conference_Titel :
Micro Electro Mechanical Systems (MEMS), 2015 28th IEEE International Conference on
Conference_Location :
Estoril
DOI :
10.1109/MEMSYS.2015.7050976