Microelectromechanical gyroscope with rotary driving motion and improved electrical properties

• US 9,470,526 B2
• Filed: 04/30/2014
• Issued: 10/18/2016
• Est. Priority Date: 11/26/2008
• Status: Active Grant

• Current Assignee: STMicroelectronics SRL (STMicroelectronics NV)
• Original Assignee: STMicroelectronics SRL (STMicroelectronics NV)
• Inventors: Coronato, Luca, Cazzaniga, Gabriele, Zerbini, Sarah
• Primary Examiner(s): Chapman, Jr., John
• Application Number:
  US14/266,676
• Publication Number:
  US 20140230548A1
• Time in Patent Office: 902 Days
• Field of Search: 735/041.2
• US Class Current: 1/1
• CPC Class Codes: G01C 19/56 Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces
• CPC Class Codes: G01C 19/5712 the devices involving a micromechanical structure
• CPC Class Codes: Y10T 29/49002 Electrical device making

Abstract

An integrated microelectromechanical structure is provided with: a die, having a substrate and a frame, defining inside it a detection region and having a first side extending along a first axis; a driving mass, anchored to the substrate, set in the detection region, and designed to be rotated in a plane with a movement of actuation about a vertical axis; and a first pair and a second pair of first sensing masses, suspended inside the driving mass via elastic supporting elements so as to be fixed with respect thereto in the movement of actuation and so as to perform a detection movement of rotation out of the plane in response to a first angular velocity; wherein the first sensing masses of the first pair and the first sensing masses of the second pair are aligned in respective directions, having non-zero inclinations of opposite sign with respect to the first axis.

Claims

1. A device, comprising:

a substrate;

a rectangular frame formed on the substrate, a first side of the frame extending along a first axis and a second side of the frame extending along a second axis that is orthogonal to the first axis;

a driving assembly elastically coupled to the substrate and positioned within the frame, at least a portion of the driving assembly being configured to move in a plane;

a first pair of sensing masses coupled to the driving assembly and positioned within the frame, the first pair of sensing masses aligned with each other along a third axis, the third axis being transverse to the first axis, the first pair of sensing masses being configured to move out of the plane to generate a first signal indicative of rotation about the first axis and rotation about the second axis;

a second pair of sensing masses coupled to the driving assembly, the second pair of sensing masses aligned with each other along a fourth axis, and the fourth axis being orthogonal to the third axis, the second pair of sensing masses being configured to move out of the plane to generate a second signal indicative of rotation about the first axis and rotation about the second axis; and

a read circuit coupled to the first pair of sensing masses and the second pair of sensing masses, the read circuit configured to detect rotation about the first axis based on the first and second signals from the first pair of sensing masses and the second pair of sensing masses, respectively.

2. The device of claim 1 wherein the first pair of sensing masses and the second pair of sensing masses have a non-rectangular shape.

3. The device of claim 2 wherein each sensing mass of the first pair of sensing masses and the second pair of sensing masses includes an outermost point formed from an intersection of a first side and a second side, the first side being substantially parallel to the first axis and the second side being substantially parallel to the second axis.

4. The device of claim 1 wherein the rectangular frame has a height from the substrate to a top surface of the rectangular frame and the first pair of sensing masses are suspended above the substrate by a distance, the height being greater than the distance.

5. The device of claim 2, further comprising a central anchor, each sensing mass of the first pair and the second pair of sensing masses including a plurality outer edges, a smallest one of the outer edges being closer to the central anchor than the other outer edges.

6. The device of claim 2 wherein each sensing mass includes at least five outer edges.

7. A device, comprising:

a substrate having a surface that includes a first axis and a second axis perpendicular to the first axis;

a central anchor, the first axis and the second axis cross each other at the central anchor;

a plurality of driving electrodes on the substrate;

a first pair of sensing masses positioned on opposite sides of the central anchor, the first pair of sensing masses being aligned with each other along a third axis that is shifted approximately 45 degrees from the first axis;

a second pair of sensing masses positioned on opposite sides of the central anchor, the second pair of sensing masses aligned with each other along a fourth axis that is shifted approximately 45 degrees from the first axis; and

a read circuit coupled to the first and second pair of sensing masses, the read circuit configured to detect rotation about the first axis from signals from both the first and second pair of sensing masses and to detection rotation about the second axis from signals from both the first and second pair of sensing masses.

8. The device of claim 7 wherein the plurality of driving electrodes are positioned around the central anchor.

9. The device of claim 7 wherein each sensing mass of the first pair and the second pair have a non-rectangular shape.

10. The device of claim 9 wherein each sensing mass includes an outermost point spaced furthest from the central anchor that is formed by an intersection of two edges.

11. The device of claim 10, further comprising a rectangular frame including a first side that extends along the first axis and a second side that extends along the second axis.

12. The device of claim 11 wherein a first one of the two edges of each sensing mass is substantially parallel to the first axis and a second one of the two edges is substantially parallel to the second axis.

13. A device, comprising:

a rectangular frame, the frame having a first side that extends substantially parallel to a first axis and a second side that extends substantially parallel to a second axis, the second axis being transverse to the first axis;

a central anchorage, the first axis crosses the second axis at the central anchorage;

a first pair of suspended sensing electrodes within the frame, the first pair of sensing electrodes being aligned with each other along a third axis that is at a non-zero angle of inclination with respect to the first and the second axis;

a second pair of suspended sensing electrodes within the frame, the second pair of sensing electrodes being aligned with each other along a fourth axis that is at a non-zero angle of inclination with respect to the first and the second axis; and

a read circuit configured to detect rotation about the first axis in response to signals from both the first pair of sensing electrodes and the second pair of sensing electrodes.

14. The device of claim 13 wherein the non-zero angle of inclination of the third axis is approximately 45 degrees.

15. The device of claim 14 wherein the non-zero angle of inclination of the fourth axis is approximately 45 degrees.

16. The device of claim 13 wherein each suspended sensing electrode of the first and second pair has a non-rectangular shape.

17. The device of claim 16 wherein each suspended sensing electrode of the first and second pair includes an outermost point that is farther from the central anchorage than any other part of the suspended sensing electrode.

18. The device of claim 13 wherein each suspended sensing electrode of each of the first and second pair includes a first non-rectangular portion and a second non-rectangular portion, the first non-rectangular portion being between the second non-rectangular portion and the central anchorage.

19. The device of claim 18 wherein the second non-rectangular portion has a larger area than the first non-rectangular portion.

20. A device, comprising:

a rectangular frame, the frame having a first side that extends substantially parallel to a first axis and a second side that extends substantially parallel to a second axis, the second axis being transverse to the first axis;

a first pair of suspended sensing electrodes within the frame, the first pair of sensing electrodes being aligned with each other along a third axis that is at a non-zero angle of inclination with respect to the first and the second axis, the first pair of sensing electrodes configured to generate a first signal indicative of rotation about the first axis and the second axis;

a second pair of suspended sensing electrodes within the frame, the second pair of sensing electrodes being aligned with each other along a fourth axis that is at a non-zero angle of inclination with respect to the first and the second axis, the second pair of sensing electrodes configured to generate a second signal indicative of rotation about the first axis and the second axis; and

a plurality of contact pads aligned along the first side of the frame along the first axis, each of the first and second pairs of sensing electrodes being coupled to the plurality of contact pads.

21. The device of claim 20, further comprising a read circuit configured to detect rotation about the first axis in response to the first signal and the second signal from the first pair of sensing electrodes and the second pair of sensing electrodes.