Uniaxial or biaxial microelectromechanical gyroscope with improved sensitivity to angular velocity detection

• US 8,661,897 B2
• Filed: 09/13/2012
• Issued: 03/04/2014
• 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): KWOK, HELEN C
• Application Number:
  US13/615,353
• Publication Number:
  US 20130061672A1
• Time in Patent Office: 537 Days
• Field of Search: 735/041.2, 735/040.4, 735/041.4, 735/143.2, 735/142.9
• US Class Current: 73/504.04
• CPC Class Codes: G01C 19/5712 the devices involving a micromechanical structure
• CPC Class Codes: Y10T 29/49002 Electrical device making
• CPC Class Codes: Y10T 29/49124 On flat or curved insulated base, e.g., printed circuit, etc.
• CPC Class Codes: Y10T 29/49826 Assembling or joining

Abstract

An integrated microelectromechanical structure is provided with: a driving mass, anchored to a substrate via elastic anchorage elements and moved in a plane with a driving movement; and a first sensing mass, suspended inside, and coupled to, the driving mass via elastic supporting elements so as to be fixed with respect to the driving mass in the driving movement and to perform a detection movement of rotation out of the plane in response to a first angular velocity; the elastic anchorage elements and the elastic supporting elements cause the detection movement to be decoupled from the driving movement. The elastic supporting elements are coupled to the first sensing mass at an end portion thereof, and the axis of rotation of the detection movement extends, within the first sensing mass, only through the end portion.

Claims

1. A device, comprising:

a substrate;

a driving mass anchored to the substrate, the driving mass having a first opening defined by a first and a second interior edge portion of the driving mass;

first and second linear elastic supporting elements; and

a first sensing mass suspended inside the first opening, the first sensing mass having;

an end portion;

first and second side portions;

a first connection portion formed where the first side portion meets the end portion, the first linear elastic supporting element extending between the first connection portion and a first location on the first interior edge portion of the driving mass; and

a second connection portion formed where the second side portion meets the end portion, the second linear elastic supporting element extending between the second connection portion and a second location on the second interior edge portion of the driving mass, a first axis of rotation extending through the first linear elastic supporting element, the second linear elastic supporting element, and an entire length of the end portion of the first sensing mass, the first sensing mass being configured to rotate about the first axis of rotation.

2. The device of claim 1, wherein the driving mass is configured to move in a plane with a driving movement and the first and second linear elastic supporting elements are configured to allow the first sensing mass to rotate out of the plane about the first axis of rotation to detect a first angular velocity.

3. The device of claim 2, wherein the first and second supporting elements are configured to fix the first sensing mass with respect to the driving mass in the driving movement and are configured to allow the first sensing mass to rotate about the first axis of rotation.

4. The device of claim 1 wherein the first sensing mass extends as a cantilever from the first and second linear elastic supporting elements, and has a main body entirely on one side of the first axis of rotation.

5. The device of claim 4, further comprising a first sensing electrode positioned on the substrate underneath the main body.

6. The device of claim 1, wherein the driving mass includes:

a second opening defined by a third and a fourth interior edge portion of the driving mass;

a third and a fourth linear elastic supporting element; and

a second sensing mass suspended inside the second opening, the second sensing mass having;

an end portion;

first and second side portions;

a first connection portion formed where the first side portion meets the end portion, the third linear elastic supporting element extending between the first connection portion and a third location on the third interior edge portion of the driving mass; and

a second connection portion formed where the second side portion meets the end portion, the fourth linear elastic supporting element extending between the second connection portion and a fourth location on the fourth-interior edge portion of the driving mass, a second axis of rotation extending through the third linear elastic supporting element, the fourth linear elastic supporting element, and an entire length of the end portion of the second sensing mass, the first sensing mass being configured to rotate about the first axis of rotation.

7. The device of claim 6, wherein the first and second sensing masses form a first pair of sensing masses, aligned in a first direction of the plane;

the end portions of the first and second sensing masses correspond to a radially more internal sides of the first and second sensing masses, respectively, with respect to a center of rotation of the driving mass.

8. A system, comprising:

a substrate;

a reading stage;

a micro-electromechanical structure electrically coupled to the reading stage, the micro-electromechanical structure including;

a driving mass anchored to the substrate, the driving mass having a first opening defined by a first and a second interior edge portion of the driving mass;

first and second linear elastic supporting elements; and

a first sensing mass suspended inside the first opening, the first sensing mass having;

an end portion;

first and second side portions;

a first connection portion formed where the first side portion meets the end portion, the first linear elastic supporting element extending between the first connection portion and a first location on the first interior edge portion of the driving mass; and

a second connection portion formed where the second side portion meets the end portion, the second linear elastic supporting element extending between the second connection portion and a second location on the second interior edge portion of the driving mass, a first axis of rotation extending through the first linear elastic supporting element, the second linear elastic supporting element, and an entire length of the end portion of the first sensing mass, the first sensing mass being configured to rotate about the first axis of rotation.

9. The system of claim 8, wherein the driving mass is configured to move in a plane with a driving movement and the first and second linear elastic supporting elements are configured to allow the first sensing mass to rotate out of the plane about the first axis of rotation to detect a first angular velocity.

10. The system of claim 9, wherein the first and second supporting elements are configured to fix the first sensing mass with respect to the driving mass in the driving movement and are configured to allow the first sensing mass to rotate about the first axis of rotation.

11. The system of claim 8 wherein the first sensing mass extends as a cantilever from the first and second linear elastic supporting elements, and has a main body entirely on one side of the first axis of rotation.

12. A method, comprising:

anchoring a driving mass to a substrate, the driving mass being configured to move in a plane with a driving movement;

forming an opening through the driving mass, the driving mass having a first and a second interior edge portion that faces the opening;

forming first and second linear elastic supporting elements;

suspending a sensing mass inside the opening of the driving mass; and

coupling the sensing mass to the driving mass with the first and second linear elastic supporting elements by;

coupling the first linear elastic supporting element between a first location on the first interior edge portion of the driving mass and a first connection portion, the first connection portion being where a first side portion of the sensing mass meets an end portion of the sensing mass; and

coupling the second linear elastic supporting element between a second location on the second interior edge portion of the driving mass and a second connection portion, the second connection portion being where a second side portion of the sensing mass meets the end portion of the sensing mass, the sensing mass being configured to rotate about a first axis that extends through the first linear elastic supporting element, the second elastic supporting element and an entire length of the end portion.

13. The method of claim 12 wherein suspending the sensing mass includes forming the sensing mass as a cantilever beam extending from the first and second elastic supporting elements.

14. The method of claim 13, wherein forming the sensing mass includes forming a main body of the sensing mass entirely on one side of the first axis.

15. The method of claim 14, further comprising forming a sensing electrode on the substrate underneath the main body.

16. A device, comprising:

a substrate;

a central anchorage region;

a driving assembly anchored to the substrate, the driving assembly having a plurality of driving electrodes around the central anchorage region;

a plurality of sensing masses positioned between ones of the plurality of driving electrodes and arranged around the central anchorage region, each sensing mass having;

a single cantilever body having a radially more internal end with respect to the central anchorage region;

a first linear connection element and a second linear connection element coupled to opposite sides of the end, each sensing mass being configured to rotate about an axis that passes through the first linear connection element, the second linear connection element, and a length of the end of the cantilever body.

17. The device of claim 16 wherein each mass has a curved end positioned opposite to the radially more internal end, the curved end including an outermost point of the mass with respect to the central anchorage region.

18. The device of claim 16 wherein each mass has five sides, where the radially more internal end has a smallest length as compared with the other 4 sides.

19. The device of claim 18 wherein there are four sensing masses configured to detect a rotation about a first axis and about a second axis that is perpendicular to the first axis, the four sensing masses are arranged in pairs, a first pair are symmetrically arranged along a third axis that is at an angle of less than 90 degrees from the first axis and the second pair are symmetrically arranged along a fourth axis, different than the third axis, that is at an angle of less than 90 degrees from the first axis.