Environmentally robust disc resonator gyroscope

• US 8,393,212 B2
• Filed: 04/01/2009
• Issued: 03/12/2013
• Est. Priority Date: 04/01/2009
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Ge, Howard H., Challoner, A. Dorian
• Primary Examiner(s): Kwok, Helen C.
• Application Number:
  US12/416,911
• Publication Number:
  US 20100251818A1
• Time in Patent Office: 1,441 Days
• Field of Search: 735/041.3, 735/041.2, 735/041.5, 735/041.6, 735/040.4, 734/93, 295/921, 295/92
• US Class Current: 73/504.13
• CPC Class Codes: G01C 19/5684 the devices involving a micromechanical structure
• CPC Class Codes: Y10T 156/10 Methods of surface bonding and/or assembly therefor

Abstract

Micromachined disc resonator gyroscopes (DRGs) are disclosed designed to be virtually immune to external temperature and stress effects. The DRG is a vibratory gyroscope that measures angular rate which is designed to have reduced sensitivity to external thermal and mechanical stress. The DRG features an integrated isolator that may be fabricated on the same wafer as the electrode wafer forming a plurality of integrated isolator beams. In addition, the DRG may include a wafer level hermetical vacuum seal, flip chip ball grid array (BGA), and vertical electrical feedthrough to improve reliability and to reduce manufacturing cost. An additional carrier layer may be used with shock stops, vertical electrical feedthrough, and the flip chip BGA. A pyrex or quartz cap with embedded getter and shock stops can be employed.

Claims

1. A resonator gyroscope, comprising:

a resonator having electrostatic electrodes having electrode sidewalls that interact with resonator sidewalls of the resonator such that vibration modes of the resonator are driven and sensed with the electrostatic electrodes to measure motion of the resonator;

an isolation layer supporting the resonator and the electrostatic electrodes in a central region, the isolation layer comprising a plurality of isolation beams each coupled to the central region at a first end and a periphery of the isolation layer at a second end; and

a carrier layer supporting the periphery of the isolation layer.

2. The resonator gyroscope of claim 1, wherein the isolation layer comprises metal traces coupled to the electrostatic electrodes in the central region traversing the plurality of isolation beams to the periphery.

3. The resonator gyroscope of claim 2, wherein the metal traces are coupled from the isolation layer at the periphery to conductive feedthroughs in the carrier layer.

4. The resonator gyroscope of claim 3, wherein the conductive feedthroughs in the carrier layer are coupled to a ball grid array (BGA).

5. The resonator gyroscope of claim 1, wherein the plurality of isolation beams comprises radial symmetric semi-circular beams.

6. The resonator gyroscope of claim 1, wherein the carrier layer comprises one or more shock stops for limiting movement of the central region of the isolation layer supporting the resonator.

7. The resonator gyroscope of claim 1, wherein the vibration modes comprise three-dimensional vibration modes of the resonator.

8. The resonator gyroscope of claim 1, further comprising a cap enclosing the resonator wherein an interior of the cap includes one or more shock stops for limiting movement of the central region of the isolation layer supporting the resonator.

9. The resonator gyroscope of claim 8, wherein the interior of the cap further includes a thin film getter material.

10. The resonator gyroscope of claim 8, wherein a vacuum is formed around the resonator and the central region of the isolation layer between the cap and the carrier layer.

11. The resonator gyroscope of claim 1, wherein the resonator, the isolation layer, and the carrier layer comprise silicon.

12. The resonator gyroscope of claim 1, wherein the resonator, the isolation layer, and the carrier layer comprise quartz.

13. A method of manufacturing a resonator gyroscope, comprising:

etching an isolation layer to form a plurality of isolation beams each coupled to a central region at a first end and a periphery of the isolation layer at a second end;

selectively bonding the isolation layer to support a resonator layer and electrostatic electrodes in the central region of the isolation layer;

etching a resonator from the resonator layer with the electrostatic electrodes having electrode sidewalls that interact with resonator sidewalls of the resonator such that vibration modes of the resonator are driven and sensed with the electrostatic electrodes to measure motion of the resonator; and

bonding a carrier layer to support the periphery of the isolation layer.

14. The method of claim 13, wherein the isolation layer comprises metal traces coupled to the electrostatic electrodes in the central region traversing the plurality of isolation beams to the periphery.

15. The method of claim 14, wherein the metal traces are coupled from the isolation layer at the periphery to conductive feedthroughs in the carrier layer.

16. The method of claim 15, wherein the conductive feedthroughs in the carrier layer are coupled to a ball grid array (BGA).

17. The method of claim 13, wherein the plurality of isolation beams comprises radial symmetric semi-circular beams.

18. The method of claim 13, wherein the carrier layer comprises one or more shock stops for limiting movement of the central region of the isolation layer supporting the resonator.

19. The method of claim 13, wherein the vibration modes comprise three-dimensional vibration modes of the resonator.

20. The method of claim 13, further comprising bonding a cap enclosing the resonator wherein a vacuum is formed around the resonator and the central region of the isolation layer between the cap and the carrier layer.

21. The method of claim 20, wherein an interior of the cap further includes a thin film getter material to aid forming the vacuum.

22. The method of claim 20, wherein an interior of the cap includes one or more shock stops for limiting movement of the central region of the isolation layer supporting the resonator.

23. The method of claim 13, wherein the resonator, the isolation layer, and the carrier layer comprise silicon.

24. The method of claim 13, wherein the resonator, the isolation layer, and the carrier layer comprise quartz.

25. A resonator gyroscope, comprising:

a resonator means for measuring motion using vibration modes;

an isolation layer for supporting the resonator means in a central region, the isolation layer comprising a plurality of isolation beams each coupled to the central region at a first end and a periphery of the isolation layer at a second end; and

a carrier layer means for supporting the periphery of the isolation layer.