Planar resonator gyroscope central die attachment

• US 7,793,541 B2
• Filed: 06/04/2007
• Issued: 09/14/2010
• Est. Priority Date: 06/04/2007
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Challoner, A. Dorian
• Primary Examiner(s): Kwok; Helen C.
• Application Number:
  US11/757,395
• Publication Number:
  US 20080295622A1
• Time in Patent Office: 1,198 Days
• Field of Search: 735/041.2, 735/041.3, 735/041.5, 735/040.4, 734/93, 734/31
• US Class Current: 73/504.13
• CPC Class Codes: G01C 19/5684 the devices involving a micromechanical structure
• CPC Class Codes: Y10T 74/1275 Electrical

Abstract

Packaging techniques for planar resonator gyroscopes, such as disc resonator gyroscopes (DRGs) are disclosed. A gyroscope die may be attached to its package substrate on a central disc area that is inboard of its embedded electrodes. This configuration eliminates contact of the die with the package substrate beneath the embedded electrodes allowing the internal electrode support structure to expand or contract freely without stress as its temperature changes. The central attachment can also be used diminish the package temperature gradients on the periphery of the die, if the thermal conductivity of the central disc attachment material is higher than the package substrate. Temperature gradients across the resonator also lead to thermoelastic damping asymmetry and rate drift. In addition, the electrical connections to the die may be formed by vertical vias within the central disc attachment area or by thin wirebonds to peripheral I/O pads on the gyro chip.

Claims

1. A packaged resonator gyroscope, comprising:

a planar resonator die including a baseplate and a planar resonator centrally mounted to the baseplate having a plurality of embedded capacitive electrodes coupled to a top side of the baseplate; and

a package attached to a bottom side of the baseplate of the planar resonator die only in a central region substantially excluded from a projected area of the plurality of the embedded capacitive electrodes coupled to the top side of the baseplate to avoid stress that would induce gap nonuniformity of the embedded capacitive electrodes under temperature changes;

wherein the plurality of the embedded capacitive electrodes are within slots in the planar resonator.

2. The packaged resonator gyroscope of claim 1, wherein the planar resonator comprises a disc resonator.

3. The packaged resonator gyroscope of claim 2, wherein the disc resonator comprises a circumferentially slotted disc.

4. The packaged resonator gyroscope of claim 3, wherein the embedded capacitive electrodes comprise one or more sense electrodes peripheral to one or more drive electrodes around the disc resonator.

5. The packaged resonator gyroscope of claim 1, wherein electrical connections to the planar resonator die are made by vias through the central region.

6. The packaged resonator gyroscope of claim 1, wherein electrical connections to the planar resonator die are made by thin wire bonds to peripheral I/O pads on a DRG chip.

7. The packaged resonator gyroscope of claim 1, wherein the planar resonator die is attached to the bottom side of the baseplate with a bonding material.

8. The packaged resonator gyroscope of claim 7, wherein the bonding material is cured to attach the package to the baseplate.

9. The packaged resonator gyroscope of claim 7, wherein thermal conductivity of the bonding material is higher than that of a substrate of the package attached to the planar resonator die.

10. A method of packaging a planar resonator gyroscope, comprising the steps of:

providing a planar resonator die including a baseplate and a planar resonator centrally mounted to the baseplate having a plurality of the embedded capacitive electrodes coupled to a top side of the baseplate;

providing a package for supporting the planar resonator die; and

attaching the package to a bottom side of the baseplate of the planar resonator die only in a central region substantially excluded from a projected area of the plurality of the embedded capacitive electrodes coupled to the top side of the baseplate to avoid stress that would induce gap nonuniformity of the embedded capacitive electrodes under temperature changes;

wherein the plurality of the embedded capacitive electrodes are within slots in the planar resonator.

11. The method of claim 10, wherein the planar resonator comprises a disc resonator.

12. The method of claim 11, wherein the disc resonator comprises a circumferentially slotted disc.

13. The method of claim 12, wherein the embedded capacitive electrodes comprise one or more sense electrodes peripheral to one or more drive electrodes around the disc resonator.

14. The method of claim 10, wherein electrical connections to the planar resonator die are made by vias through the central region.

15. The method of claim 10, wherein electrical connections to the planar resonator die are made by thin wire bonds to peripheral I/O pads on a DRG chip.

16. The method of claim 10, further comprising applying a bonding material to the package to attach the planar resonator die to the bottom side of the baseplate.

17. The method of claim 16, further comprising curing the bonding material to attach the package to the baseplate.

18. The method of claim 16, wherein thermal conductivity of the bonding material is higher than that of a substrate of the package attached to the planar resonator die.

19. A packaged resonator gyroscope, comprising:

a planar resonator die means for sensing rotation including a baseplate and a planar resonator centrally mounted to the baseplate having a plurality of embedded capacitive electrodes coupled to a top side of the baseplate;

a package means for supporting the planar resonator die means; and

a bonding means for attaching the package means to a bottom side of the baseplate of the planar resonator die means only in a central region substantially excluded from a projected area of the plurality of the embedded capacitive electrodes coupled to the top side of the baseplate to avoid stress that would induce gap nonuniformity of the embedded capacitive electrodes under temperature changes;

wherein the plurality of the embedded capacitive electrodes are within slots in the planar resonator.

20. The packaged resonator gyroscope of claim 19, wherein electrical connections to the planar resonator die means are made by vias through the central region, the bonding means and the package means.