Method for producing a disk resonator gyroscope

• US 9,046,541 B1
• Filed: 10/09/2012
• Issued: 06/02/2015
• Est. Priority Date: 04/30/2003
• Status: Active Grant

• Current Assignee: HRL Laboratories LLC (The Boeing Co.), The Boeing Co.
• Original Assignee: HRL Laboratories LLC (The Boeing Co.), The Boeing Co.
• Inventors: Kubena, Randall L., Chang, David T., Larson, Robert L.
• Primary Examiner(s): Kim, Paul D
• Application Number:
  US13/648,041
• Time in Patent Office: 966 Days
• Field of Search: 29/253.5, 295/921, 295/94, 296/091, 735/033, 735/040.4, 735/041.2, 333/186, 333/197, 333/199
• US Class Current: 1/1
• CPC Class Codes: G01C 19/5684 the devices involving a micromechanical structure
• CPC Class Codes: G01P 1/00 Details of instruments
• CPC Class Codes: H03H 2009/02283 Vibrating means
• CPC Class Codes: H03H 2009/02496 Horizontal, i.e. parallel to the substrate plane
• CPC Class Codes: H03H 3/0072 of microelectro-mechanical resonators or networks micromembranes or microbeams B81B2203/01; manufacture of microstructural devices in general B81C
• CPC Class Codes: H03H 9/02244 of microelectro-mechanical resonators
• CPC Class Codes: H03H 9/0552 the device and the other elements being mounted on opposite sides of a common substrate
• CPC Class Codes: H03H 9/1057 for microelectro-mechanical devices
• CPC Class Codes: H03H 9/2436 Disk resonators

Abstract

A method for producing a disk resonator gyroscope includes providing a base substrate and a handle wafer with a release hole, bonding a release wafer to the handle wafer, bonding a resonator wafer to the release wafer, etching the resonator wafer to form a disk resonator with a central pillar, and sense and drive electrodes, selectively applying a conductive film onto the disk resonator on a side of the disk resonator opposite the release wafer, on the outer edge of the disk resonator, and on the surfaces of the sense and drive electrodes facing the outer edge of the disk resonator, bonding the sense and drive electrodes and the central pillar of the disk resonator to the base substrate, and releasing the handle wafer by introducing a dry release agent into the release hole to undercut the release wafer.

Claims

1. A method for producing a disk resonator gyroscope comprising:

providing a base substrate;

providing a handle wafer with a release hole;

bonding a release wafer to the handle wafer;

bonding a resonator wafer to the release wafer;

etching the resonator wafer to form a disk resonator, the disk resonator having an outer edge and a central pillar, and to form a sense electrode and a drive electrode, the sense and drive electrodes outside the outer edge of the disk resonator and each of the sense and the drive electrodes having a surface facing the outer edge of the disk resonator;

selectively applying a conductive film onto the disk resonator such that the conductive film is on a side of the disk resonator opposite the release wafer, on the outer edge of the disk resonator, and on the surfaces of the sense and drive electrodes that are facing the outer edge of the disk resonator;

selectively applying a conductive metal onto the sense and drive electrodes and onto the central pillar of the disk resonator;

bonding the sense and drive electrodes and the central pillar of the disk resonator to the base substrate; and

releasing the handle wafer by introducing a dry release agent into the release hole such that it undercuts the release wafer.

2. The method for producing a disk resonator gyroscope of claim 1 wherein:

the base substrate is fused quartz;

the handle wafer is fused quartz;

the release wafer is silicon; and

the resonator wafer is fused quartz.

3. The method for producing a disk resonator gyroscope of claim 1 wherein providing the base substrate further comprises:

etching the base substrate to form first, second, and third raised areas;

depositing a metal on the first, second and third raised areas;

wherein the first raised area is bonded to the central pillar;

wherein the second raised area is bonded to the sense electrode; and

wherein the third raised area is bonded to the drive electrode.

4. The method for producing a disk resonator gyroscope of claim 1 wherein bonding the release wafer to the handle wafer further comprises thinning the release wafer.

5. The method for producing a disk resonator gyroscope of claim 4 wherein thinning the release wafer comprises grinding and chemical mechanical planarization.

6. The method for producing a disk resonator gyroscope of claim 1 wherein:

bonding the resonator wafer to the release wafer further comprises thinning the resonator wafer; and

wherein thinning the resonator wafer comprises grinding and chemical mechanical planarization.

7. The method for producing a disk resonator gyroscope of claim 1 wherein etching the resonator wafer to form the disk resonator, the sense electrode, and the drive electrode comprises performing deep reactive ion etching (DRIE).

8. The method for producing a disk resonator gyroscope of claim 1 wherein selectively applying the conductive film comprises atomic layer deposition of a noble metal.

9. The method for producing a disk resonator gyroscope of claim 8 wherein the noble metal is one of Pt, Ru, Rh, Pd, Re, or Ir.

10. The method for producing a disk resonator gyroscope of claim 1 wherein:

selectively applying the conductive film comprises using a conformal mask; and

using the conformal mask comprises using spray lithography.

11. The method for producing a disk resonator gyroscope of claim 1 wherein bonding the sense and drive electrodes and the central pillar of the disk resonator to the base substrate comprises metal to metal thermal compression.

12. The method for producing a disk resonator gyroscope of claim 1 wherein releasing the handle wafer by introducing the dry release into the release hole comprises using a XeF₂ dry release process.

13. The method for producing a disk resonator gyroscope of claim 1 further comprising vacuum sealing the disk resonator gyroscope with a quartz capping wafer.

14. The method for producing a disk resonator gyroscope of claim 1 wherein selectively applying the conductive metal onto the sense and drive electrodes and onto the central pillar of the disk resonator comprises applying gold over the conductive film on the central pillar and on the sense and drive electrodes on the side of the disk resonator opposite the release wafer.

15. The method for producing a disk resonator gyroscope of claim 1 further comprising:

selectively applying an adhesion ALD layer before applying the conductive film onto the disk resonator such that the adhesion ALD layer is on a side of the disk resonator opposite the release wafer, on the outer edge of the disk resonator, and on the surfaces of the sense and drive electrodes that are facing the outer edge of the disk resonator.