FLEXURE BEARING TO REDUCE QUADRATURE FOR RESONATING MICROMACHINED DEVICES

• US 20130298671A1
• Filed: 09/16/2011
• Published: 11/14/2013
• Est. Priority Date: 09/18/2010
• Status: Active Grant

• Current Assignee: Semiconductor Components Industries LLC (ON Semiconductor Corporation)
• Original Assignee: Fairchild Semiconductor Corporation (ON Semiconductor Corporation)
• Inventors: Acar, Cenk, Bloomsburgh, John Gardner
• Granted Patent: US 9,352,961 B2
• Time in Patent Office: Days
• US Class Current: 73/504.12
• CPC Class Codes: B81C 1/00523 Etching material
• 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

Abstract

An example include microelectromechanical die for sensing motion that includes a fixed portion, an anchor coupled to the fixed portion, a first nonlinear suspension member coupled to anchor on a side of the anchor, a second nonlinear suspension member coupled to the anchor on the same side of the anchor, the second nonlinear suspension member having a shape and location mirroring the first nonlinear suspension member about an anchor bisecting plane and a proof-mass that is planar, the proof mass suspended at least in part by the first nonlinear suspension member and the second nonlinear suspension member such that the proof-mass is rotable about the anchor and is slideable in a plane parallel to the fixed portion.

Claims

1. A microelectromechanical die for sensing motion, comprising:

a fixed portion;

an anchor coupled to the fixed portion;

a first nonlinear suspension member coupled to anchor on a side of the anchor;

a second nonlinear suspension member coupled to the anchor on the same side of the anchor, the second nonlinear suspension member having a shape and location mirroring the first nonlinear suspension member about an anchor bisecting plane; and

a proof-mass that is planar, the proof mass suspended at least in part by the first nonlinear suspension member and the second nonlinear suspension member such that the proof-mass is rotable about the anchor and is slideable in a plane parallel to the fixed portion.

2. The die of claim 1, wherein the first nonlinear suspension member has a C-shape.

3. The die of claim 2, wherein the C-shape includes a inner portion coupled to the anchor and extending toward the anchor bisecting plane, a center portion having a proximal portion and a distal portion, with a proximal portion coupled to the inner portion and a distal portion extending away from the anchor along the anchor bisecting plane and coupled to a outer portion extending away from the anchor bisecting plane.

4. The die of claim 3, wherein the outer portion of the first nonlinear suspension member has a proximal portion coupled to the center portion of the first nonlinear suspension member, and a distal portion extending away from the anchor bisecting plane, with a fourth portion of the first nonlinear suspension member coupled to the distal portion of the outer portion at a proximal portion of the fourth portion, and extending toward the anchor to a distal portion of the fourth portion that is coupled to a fifth portion of the first nonlinear suspension member that extends toward the anchor bisecting plane.

5. The die of claim 3, wherein the inner portion and the outer portion are linear and parallel.

6. The die of claim 5, wherein the center portion is perpendicular the inner portion and the outer portion.

7. The die of claim 3, wherein the center portion is parallel the anchor bisecting plane.

8. The die of claim 3, wherein the anchor, the first nonlinear suspension member, the second nonlinear suspension member and the proof-mass are formed of a monolithic material.

9. The die of claim 8, wherein the fixed portion comprises a fixed monolithic material other than the monolithic material of the anchor, the first nonlinear suspension member, the second nonlinear suspension member and the proof-mass.

10. The die of claim 9, wherein the fixed portion comprises a fixed monolithic material the same as the monolithic material of the anchor, the first nonlinear suspension member, the second nonlinear suspension member and the proof-mass.

11. The die of claim 1, wherein the die is wafer shaped, with each of the first nonlinear suspension member and the second nonlinear suspension member have a substantially rectangular cross-section with the height of the cross-section smaller than the width.

12. A method comprising:

etching a material to define an anchor;

etching the material to define a first nonlinear suspension member coupled to anchor on a side of the anchor;

etching the material to define a second nonlinear suspension member coupled to the anchor on the same side of the anchor, the second nonlinear suspension member having a shape and location mirroring the first nonlinear suspension member about an anchor bisecting plane; and

etching the material to define a proof-mass that is planar, the proof mass suspended at least in part by the first nonlinear suspension member and the second nonlinear suspension member such that the proof-mass is rotable about the anchor and is slideable in a plane parallel to the substrate.

13. The method of claim 12, wherein etching includes deep reactive-ion etching.

14. The method of claim 12, wherein the first nonlinear suspension member and the second nonlinear suspension member are part of a first set, comprising etching the material to define a second set of nonlinear suspension members opposite the first set.

15. The method of claim 14, comprising etching a third set of nonlinear suspension members for coupling the anchor to the proof-mass and etching a fourth set of nonlinear suspension members for coupling the anchor to the proof-mass, wherein the third set and the fourth set have a similar for factor to the first set and the second set and are bisected by a second anchor bisecting plane perpendicular the first.

16. A method for sensing motion with a microelectromechanical die, comprising:

rotating a proof mass with respect to an anchor that is coupled to a substrate by;

deforming a first nonlinear suspension member, that couples the proof-mass to a first side of the anchor, out-of-plane of the plane of the proof-mass, above the proof-mass; and

deforming a second nonlinear suspension member, that couples the proof-mass to the first side of the anchor, out-of-plane of the plane of the proof-mass on an opposite first side of the plane of the proof-mass, below the proof-mass.

17. The method of claim 16, wherein deforming the second nonlinear suspension member provides out-of-plane motion below the proof-mass that cancels out the out-of-plane motion above the proof-mass

18. The method of claim 16, wherein,

deforming a third nonlinear suspension member, that couples the proof-mass to a second side of the anchor, out-of-plane of the plane of the proof-mass;

and

deforming a fourth nonlinear suspension member, that couples the proof-mass to the second side of the anchor, out-of-plane of the plane of the proof-mass on an opposite side of the plane of the proof-mass.

19. The method of claim 16, wherein, the second side is opposite the first side, deforming a third nonlinear suspension member includes deforming the third nonlinear suspension member below the plane of the proof-mass;

and deforming the fourth nonlinear suspension member, includes positioning the deforming the fourth nonlinear suspension member above the plane of the proof-mass.

20. The method of claim 19, wherein a plane that bisects the anchor vertically and passes between the first and second nonlinear suspension members, and between the third and fourth nonlinear suspension members.