Methods for fabricating silicon MEMS gyroscopes with upper and lower sense plates

Patent metadata

Field	Value
Publication number	US-11530917-B2
Application number	US-201916580618-A
Country	US
Kind code	B2
Filing date	Sep 24, 2019
Priority date	Sep 24, 2018
Publication date	Dec 20, 2022
Grant date	Dec 20, 2022

Abstract

Methods for fabricating MEMS tuning fork gyroscope sensor system using silicon wafers. This provides the possibly to avoid glass. The sense plates can be formed in a device layer of a silicon on insulator (SOI) wafer or in a deposited polysilicon layer in a few examples.

First claim

What is claimed is:

1. A method for fabricating tuning fork gyroscope sensor, comprising:
fabricating at least one sense plate on a silicon sense plate wafer;
bonding the sense plate wafer to a device layer in which a proof mass is formed; and
forming through silicon vias through the sense plate wafer having the sense plate and filling the vias to provide electrical connections to the sense plate to form the tuning fork gyroscope sensor;

wherein the bonding the sense plate wafer to the device layer is performed in a vacuum to yield a vacuum sealed sensor.

2. The method as claimed in claim 1 , further comprising
filling the vias to provide electrical connections to drive electrodes to form the tuning fork gyroscope sensors.

3. The method as claimed in claim 1 , further comprising direct bonding the sense plate wafer containing the sense plate to the device layer.

4. The method as claimed in claim 1 , further comprising metal bonding the sense plate wafer containing the sense plate to the device layer.

5. A method for fabricating a tuning fork gyroscope sensor, comprising:
fabricating at least one sense plate on a silicon sense plate wafer;
bonding the sense plate wafer to a device layer in which a proof mass is formed;
forming through silicon vias through the sense plate wafer having the sense plate and filling the vias to provide electrical connections to the sense plate to form the tuning fork gyroscope sensor;
providing a sealing ring around the proof mass; and
evacuating a volumetric region in the sealing ring and around the proof mass.

6. The method as claimed in claim 5 , further comprising fabricating another silicon sense plate on an other side of the proof mass.

7. The method as claimed in claim 5 , further comprising directly bonding the sense plate wafer to the device layer.

8. The method as claimed in claim 5 , further comprising metal bonding the sense plate wafer to the device layer.

Assignees

• Charles Stark Draper Laboratory Inc

Inventors

• Cook Eugene H
• Bernstein Jonathan J
• Bancu Mirela G
• Weinberg Marc Steven
• Sawyer William

Classifications

• G01C19/5628

  Manufacturing; Trimming; Mounting; Housings · CPC title

• B81C2203/036

  Fusion bonding · CPC title

• G01C19/5621 Primary

  the devices involving a micromechanical structure · CPC title

• B81C2201/0133

  Wet etching · CPC title

• B81C2203/0118

  Bonding a wafer on the substrate, i.e. where the cap consists of another wafer · CPC title