Microelectromechanical structure with enhanced rejection of acceleration noise

Patent metadata

Field	Value
Publication number	US-11079229-B2
Application number	US-201916263416-A
Country	US
Kind code	B2
Filing date	Jan 31, 2019
Priority date	May 11, 2009
Publication date	Aug 3, 2021
Grant date	Aug 3, 2021

Abstract

An integrated MEMS structure includes a driving assembly anchored to a substrate and actuated with a driving movement. A pair of sensing masses suspended above the substrate and coupled to the driving assembly via elastic elements is fixed in the driving movement and performs a movement along a first direction of detection, in response to an external stress. A coupling assembly couples the pair of sensing masses mechanically to couple the vibration modes. The coupling assembly is formed by a rigid element, which connects the sensing masses and has a point of constraint in an intermediate position between the sensing masses, and elastic coupling elements for coupling the rigid element to the sensing masses to present a first stiffness to a movement in phase-opposition and a second stiffness, greater than the first, to a movement in phase, of the sensing masses along the direction of detection.

First claim

The invention claimed is:

1. A device, comprising:
a substrate;
an anchor attached to the substrate;
a first pair of sensing masses coupled to the anchor and aligned along a first axis; and
a second pair of sensing masses coupled to the first pair of sensing masses and aligned along the first axis, a first one of the second pair of sensing masses being separated from a second one of the second pair of sensing masses by the first pair of sensing masses.

2. The device of claim 1 , further comprising a rigid connector coupled between a first one of the first pair of sensing masses and a second one of the first pair of sensing masses.

3. The device of claim 2 wherein the rigid connector extends along the first axis between the first and second ones of the first pair of sensing masses.

4. The device of claim 1 , further comprising:
a first elastic support connected between a first one of the second pair of sensing masses and the first one of the first pair of sensing masses; and
a second elastic support connected between a second one of the second pair of sensing masses and the second one of the first pair of sensing masses.

5. The device of claim 1 , further comprising a pair of driving masses coupled to the second pair of sensing masses.

6. The device of claim 5 , further comprising:
a first elastic support connected between a first one of the driving masses and a first one of the second pair of sensing masses; and
a second elastic support connected between a second one of the driving masses and a second one of the second pair of sensing masses.

7. The device of claim 5 wherein each driving mass of the pair of driving masses includes an opening, and one of the sensing masses of the second pair of the sensing masses is positioned within the opening of each of the driving masses.

8. The device of claim 5 wherein the pair of driving masses are C-shaped masses.

9. The device of claim 8 wherein the second pair of sensing masses are C-shaped masses, and the first pair of sensing masses are positioned at least partially within openings defined by the C-shaped masses of the second pair of sensing masses.

10. The device of claim 9 wherein the first pair of sensing masses are rectangular masses.

11. The device of claim 1 , further comprising:
a plurality of fixed electrodes coupled to the substrate and having respective fixed positions with respect to the substrate; and
a plurality of mobile electrodes coupled to the second pair of sensing masses, each mass of the second pair of sensing masses being coupled to at least one of the plurality of mobile electrodes, the plurality of mobile electrodes being capacitively coupled to the plurality of fixed electrodes.

12. The device of claim 11 wherein each of the mobile electrodes is positioned between a respective pair of the plurality of fixed electrodes.

13. The device of claim 11 wherein the plurality of fixed electrodes includes a first fixed electrode between the substrate and a first one of the first pair of sensing masses, and a second fixed electrode between the substrate and a second one of the first pair of sensing masses.

14. A method, comprising:
forming a gyroscope, the forming the gyroscope including:
attaching an anchor to a substrate;
coupling a first pair of sensing masses to the anchor, the first pair of sensing masses being aligned along a first axis; and
coupling a second pair of sensing masses to the first pair of sensing masses, the second pair of sensing masses being aligned along the first axis, a first one of the second pair of sensing masses being separated from a second one of the second pair of sensing masses by the first pair of sensing masses.

15. The method of claim 14 , further comprising:
mechanically coupling a first one of the first pair of sensing masses to a second one of the first pair of sensing masses by a rigid connector.

16. The method of claim 14 , further comprising:
connecting a first elastic support between a first one of the second pair of sensing masses and the first one of the first pair of sensing masses; and
connecting a second elastic support connected between a second one of the second pair of sensing masses and the second one of the first pair of sensing masses.

17. An electronic device, comprising:
a driving circuit;
a reading circuit; and
a gyroscope coupled to the driving circuit and the reading circuit, the gyroscope including:
a substrate;
an anchor attached to the substrate;
a first pair of sensing masses coupled to the anchor and aligned along a first axis;
a second pair of sensing masses coupled to the first pair of sensing masses and aligned along the first axis, a first one of the second pair of sensing masses being separated from a second one of the second pair of sensing masses by the first pair of sensing masses; and
a pair of driving masses coupled to the second pair of sensing masses.

18. The electronic device of claim 17 wherein the pair of driving masses of the gyroscope are C-shaped masses, the second pair of sensing masses are C-shaped masses, and the first pair of sensing masses are rectangular masses.

19. The electronic device of claim 18 wherein the first pair of sensing masses are positioned at least partially within openings defined by the C-shaped masses of the second pair of sensing masses, and the second pair of sensing masses are positioned at least partially within openings defined by the C-shaped masses of the driving masses.

20. The electronic device of claim 17 wherein the driving circuit is configured to drive the pair of driving masses, and the reading circuit is configured to detect displacements of the sensing masses in response to an angular velocity of the MEMS gyroscope.

Assignees

• St Microelectronics Srl

Inventors

• Coronato Luca
• Cazzaniga Gabriele

Classifications

• Y10T29/49002

  Electrical device making · CPC title

• G01C19/5747 Primary

  each sensing mass being connected to a driving mass, e.g. driving frames · CPC title

• G01C19/5712

  the devices involving a micromechanical structure · CPC title

• G01P9/02

  Physics · mapped topic