An all-silicon process platfom for wafer-level vacuum packaged MEMS devices

Date

2021-01-01

Author

Torunbalci, Mustafa Mert
Gavcar, Hasan Dogan
Yesil, Ferhat
Alper, Said Emre
Akın, Tayfun

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This paper introduces a novel, inherently simple, and all-silicon wafer-level fabrication and hermetic packaging method developed for MEMS devices. The proposed method uses two separate SOI wafers to form highly-doped through-silicon vias (TSVs) and suspended MEMS structures, respectively. These SOI wafers are then bonded by Au-Si eutectic bonding at 400°C, achieving hermetic sealing and signal transfer without requiring any complex via or trench refill process steps. The package vacuum is measured using encapsulated MEMS resonators to be as low as 15 mTorr with the help of successfully activated thin-film getters. The combined fabrication and packaging yield is around %89 and chips still maintain a package pressure below 100 mTorr after more than 6 years. The packages show an extremely high strong bonding strength (>40 MPa) and are proved to remain hermetic after temperature cycling (25°C-85°C) and harsh temperature shock (5 min@300°C) tests. The all-silicon MEMS resonators fabricated and packaged using the proposed method project up to a 2.3X enhancement in the bias instability and ~4X in the temperature sensitivity of frequency output compared to an identical MEMS resonator fabricated using the silicon-on-glass (SOG) technology.

Subject Keywords

Wafer level vacuum packaging, Through silicon via (TSV), MEMS devices

URI

https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85104583056&origin=inward
https://hdl.handle.net/11511/90864

Journal

IEEE Sensors Journal

DOI

https://doi.org/10.1109/jsen.2021.3073928

Collections

Department of Electrical and Electronics Engineering, Article

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Citation Formats

M. M. Torunbalci, H. D. Gavcar, F. Yesil, S. E. Alper, and T. Akın, “An all-silicon process platfom for wafer-level vacuum packaged MEMS devices,” IEEE Sensors Journal, pp. 0–0, 2021, Accessed: 00, 2021. [Online]. Available: https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85104583056&origin=inward.