TWO DEGREE OF FREEDOM DITHERING PLATFORM FOR MEMS SENSOR CALIBRATION

• US 20120272731A1
• Filed: 01/06/2012
• Published: 11/01/2012
• Est. Priority Date: 04/27/2011
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Supino, Ryan, Cabuz, Eugen, Johnson, Burgess R., Horning, Robert D.
• Granted Patent: US 8,887,550 B2
• Time in Patent Office: Days
• US Class Current: 73/504.12
• CPC Class Codes: B81B 2201/03 Microengines and actuators
• CPC Class Codes: B81C 1/00134 comprising flexible or deformable structures manufacture of MEMS devices for specific applications, see relevant places, e.g. gyroscopes G01C19/5719, pressure sensors G01L9/0042, accelerometers G01P15/0802, acoustic transducers or diaphragms therefor H04R31/00
• CPC Class Codes: B81C 2203/03 Bonding two components
• CPC Class Codes: G01D 5/34 the beams of light being detected by photocells
• CPC Class Codes: G01P 21/00 Testing or calibrating of apparatus or devices covered by the preceding groups
• CPC Class Codes: Y10T 29/49002 Electrical device making

Abstract

Systems and methods for two degree of freedom dithering for micro-electromechanical system (MEMS) sensor calibration are provided. In one embodiment, a method for a device comprises forming a MEMS sensor layer, the MEMS sensor layer comprising a MEMS sensor and an in-plane rotator to rotate the MEMS sensor in the plane of the MEMS sensor layer. Further, the method comprises forming a first and second rotor layer and bonding the first rotor layer to a top surface and the second rotor layer to the bottom surface of the MEMS sensor layer, such that a first and second rotor portion of the first and second rotor layers connect to the MEMS sensor. Also, the method comprises separating the first and second rotor portions from the first and second rotor layers, wherein the first and second rotor portions and the MEMS sensor rotate about an in-plane axis of the MEMS sensor layer.

Claims

1. A micro-electromechanical system (MEMS) sensing device, the device comprising:

a MEMS sensor formed in a plane of a MEMS sensor layer;

an in-plane rotator configured to dither the MEMS sensor in the plane of the MEMS sensor layer; and

an out-of-plane rotator configured to dither the MEMS sensor about an axis in the plane of the MEMS sensor layer.

2. The MEMS sensing device of claim 1, wherein the MEMS sensor is at least one of:

a gyroscope; and

an accelerometer.

3. The MEMS sensing device of claim 1, wherein the in-plane rotator comprises a circular interdigitated comb drive configured to rotationally oscillate the MEMS sensor in the plane of the MEMS sensor layer, the in-plane rotator being formed in the MEMS sensor layer.

4. The MEMS sensing device of claim 3, wherein the circular interdigitated comb drive rotationally oscillates the MEMS sensor a defined angular distance from a non-oscillating position.

5. The MEMS sensing device of claim 3, wherein the circular interdigitated comb drive comprises:

a plurality of in-plane driving electrodes; and

a plurality of in-plane driven electrodes, wherein the plurality of in-plane driven electrodes and plurality of in-plane driving electrodes are circularly arranged around the MEMS sensor, wherein the plurality of in-plane driven electrodes move in response to electric fields produced by the in-plane driving electrodes.

6. The MEMS sensing device of claim 1, wherein the out-of-plane rotator comprises:

a first rotor layer, the first rotor layer comprising a first rotor portion connected to the MEMS sensor, wherein the first rotor portion rotates about the axis in the plane of the MEMS sensor layer;

a second rotor layer, the second rotor layer comprising a second rotor portion connected to the MEMS sensor, wherein the second rotor portion rotates about the axis in the plane of the MEMS sensor rotor layer.

7. The MEMS sensing device of claim 6, wherein the first rotor layer and the second rotor layer comprise out-of-plane driven electrodes that respond to electrical fields such that the first rotor portion, the second rotor portion and the MEMS sensor oscillate about an axis in the plane of the MEMS sensor layer.

8. The MEMS sensing device of claim 7, wherein the out-of-plane driven electrodes oscillate the MEMS sensor a defined angular distance from a non-oscillating position.

9. The MEMS sensing device of claim 7, further comprising out-of-plane driving electrodes to provide the electrical fields.

10. The MEMS sensing device of claim 6, wherein the first rotor layer and the second rotor layer are supported by a connection between the in-plane rotator and the MEMS sensor.

11. The MEMS sensing device of claim 6, wherein the first rotor layer and the second rotor layer comprise traces that electrically connect to the in-plane rotor and the MEMS sensor.

12. A method for fabricating a micro-electromechanical system (MEMS) sensing device, the method comprising:

forming a MEMS sensor layer, the MEMS sensor layer comprising;

a MEMS sensor; and

an in-plane rotator configured to rotate the MEMS sensor in the plane of the MEMS sensor layer;

forming a first rotor layer and a second rotor layer;

bonding the first rotor layer to a top surface of the MEMS sensor layer and bonding the second rotor layer to the bottom surface of the MEMS sensor layer, such that a first rotor portion of the first rotor layer and a second rotor portion of the second rotor layer connect to the MEMS sensor; and

separating the first rotor portion from the first rotor layer and the second rotor portion from the second rotor layer, wherein the first rotor portion, MEMS sensor, and second rotor portion rotate about an axis in the plane of the MEMS sensor layer.

13. The method of claim 12, wherein forming the in-plane rotator comprises:

forming a circular interdigitated comb drive; and

forming suspension connections between the circular interdigitated comb drive and the MEMS sensor.

14. The method of claim 13, wherein the suspension connections are folded beam torsional suspension connections.

15. The method of claim 13, wherein the structure of the circular interdigitated comb drive allows the MEMS sensor to rotate a defined angular distance from a non-rotating position.

16. The method of claim 12, wherein forming the first rotor layer and the second rotor layer comprises:

forming out-of-plane driven electrodes over the first rotor portion and the second rotor portion; and

forming traces configured to provide electrical connections to the in-plane rotator.

17. The method of claim 16, further comprising:

bonding a first out-of-plane driving layer to the first rotor layer;

bonding a second out-of-plane driving layer to the second rotor layer, wherein the first out-of-plane driving layer and second out-of-plane driving layer comprise driving electrodes that interact with the out-of-plane driven electrodes to rotate the MEMS sensor about the axis in the plane of the MEMS sensor layer.

18. The method of claim 12, wherein bonding the first rotor layer to a top surface of the MEMS sensor layer and bonding the second rotor layer to the bottom surface of the MEMS sensor layer comprises anodically bonding the first rotor layer and the second rotor layer to the in-plane rotator and anodically bonding the first rotor portion and the second rotor portion to the MEMS sensor.

19. A micro-electromechanical system (MEMS) gyroscope, the MEMS gyroscope comprising:

a MEMS gyroscope layer, the MEMS gyroscope layer comprising;

a MEMS sensor; and

a first in-plane rotator configured to rotate the MEMS sensor in the plane of the MEMS gyroscope layer;

a first rotor layer bonded to the MEMS gyroscope layer, the first rotor layer comprising a first rotor portion connected to the MEMS sensor; and

a second rotor layer bonded to the MEMS gyroscope layer, the second rotor layer comprising a second rotor portion connected to the MEMS sensor, wherein the first rotor portion, the second rotor portion, and the MEMS sensor rotate about an axis in the plane of the MEMS gyroscope layer.

20. The MEMS gyroscope of claim 19, wherein the first in-plane rotator is a circular interdigitated comb drive.