MICRO-ELECTROMECHANICAL DEVICE COMPRISING A MOBILE MASS THAT CAN MOVE OUT-OF-PLANE

• US 20150309069A1
• Filed: 12/24/2013
• Published: 10/29/2015
• Est. Priority Date: 12/27/2012
• Status: Active Grant

• Current Assignee: Commissariat a L'Energie Atomique (French Alternative Energies and Atomic Energy Commission), Tronic's Microsystems
• Original Assignee: Commissariat a L'Energie Atomique (French Alternative Energies and Atomic Energy Commission), Tronics Microsystems S.A. (TDK Corporation)
• Inventors: Jourdan, Guillaume, Boillot, Francois-Xavier, Laoubi, Remi
• Granted Patent: US 10,094,851 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B81B 2201/025 Inertial sensors not provided for in B81B2201/0235 - B81B2201/0242
• CPC Class Codes: B81B 2203/0154 Torsion bars
• CPC Class Codes: B81B 2203/0163 Spring holders
• CPC Class Codes: B81B 2203/051 Translation according to an axis parallel to the substrate
• CPC Class Codes: B81B 2203/058 Rotation out of a plane parallel to the substrate
• CPC Class Codes: B81B 3/0051 For defining the movement, i.e. structures that guide or limit the movement of an element mechanical arrangements for preventing or damping vibration or shock H01H3/60
• CPC Class Codes: G01P 15/0802 Details
• CPC Class Codes: G01P 15/123 by piezo-resistive elements, e.g. semiconductor strain gauges
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: G01P 15/18 in two or more dimensions
• CPC Class Codes: G01P 2015/0817 for pivoting movement of the mass, e.g. in-plane pendulum
• CPC Class Codes: G01P 2015/0871 using stopper structures for limiting the travel of the seismic mass

Abstract

The invention relates to a micro-electromechanical device used as a force sensor, comprising a mobile mass connected to at least one securing zone by means of springs or deformable elements, and means for detecting the movement of the mobile mass, the mobile mass having an outer frame and an inner body, the outer frame and the inner body being connected by at least two flexible portions forming integral decoupling springs on two separate sides of the outer frame.

Claims

1. A micro-electromechanical device formed from a semiconductor substrate having its layers defining planes along axes x and y, the axis perpendicular to the layers defining an axis z, said device comprising:

at least one anchoring area which is fixed with respect to the substrate, and

at least one mobile mass, capable of displacing out of the substrate plane along axis z by rotation around a swivel axis directed along axis x, and

at least one deformable element, said deformable element connecting the mobile mass to the anchoring area,

at least one means for detecting the displacement of the mobile mass, wherein the mobile mass has a first portion forming a support structure and a second portion forming the main body of the mobile mass, said first portion being connected to the anchoring area by the deformable element, said first and second portions being connected by at least two flexible portions forming decoupling springs fastened to two different sides of said first portion and in that it comprises at least one area of cooperation between the second portion and the substrate, forming a stop limiting the displacement of the second portion of the mobile mass relative to the anchoring area.

2. The device of claim 1, wherein the first portion forms a frame surrounding the second portion forming the main body of the mobile mass.

3. The device of claim 1, wherein the second portion forming the main body of the mobile mass is arranged at the periphery of the first portion.

4. The device of claim 1, wherein the flexible portions are spaced apart by a distance along axis y greater than half the length along axis y of the inner body of the mobile mass.

5. The device of claim 1, wherein the flexible portions are flexibly-deformable beams.

6. The device of claim 1, wherein the flexible portions comprise a plurality of consecutive segments having a non-zero angle relative to one another.

7. The device of claim 1, wherein the device comprises at least four flexible portions, said flexible portions being arranged two by two opposite each other.

8. The device of claim 1, wherein the area forming a stop for the main body of the mobile mass is arranged in front of the side of the mobile mass located opposite to the anchoring area.

9. The device of claim 1, wherein the area forming a stop for the main body of the mobile mass is a pillar anchored on the substrate and fitting into a recess of the main body of the mobile mass.

10. The device of claim 8, wherein the stop has a T shape in top view.

11. The device of claim 8, wherein the lateral sides of the stop have convex portions.

12. The device of claim 8, wherein the main body of the mobile mass has a recess with a shape substantially complementary to that of the stop.

13. The device of claim 8, wherein areas forming lateral stops are arranged opposite the lateral sides of the mobile mass.

14. The device of claim 13, wherein the areas forming lateral stops have projections of rounded shape.

15. The device of claim 1, comprising at least one first flexible portion along axis x and at least one second flexible portion along axis y.