Microelectromechanical systems devices and methods for the fabrication thereof

• US 9,003,886 B2
• Filed: 04/27/2012
• Issued: 04/14/2015
• Est. Priority Date: 04/27/2012
• Status: Active Grant

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Freescale Semiconductor, Inc. (NXP Semiconductors NV)
• Inventors: Lin, Yizhen, Jo, Sung Jin, Zhang, Lisa Z.
• Primary Examiner(s): KWOK, HELEN C
• Application Number:
  US13/458,950
• Publication Number:
  US 20130283913A1
• Time in Patent Office: 1,082 Days
• Field of Search: 735/143.2, 735/143.6, 735/143.8, 735/041.4, 735/040.4, 735/041.2
• US Class Current: 73/514.32
• CPC Class Codes: G01P 15/0802 Details
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: G01P 2015/0814 for translational movement of the mass, e.g. shuttle type
• CPC Class Codes: Y10T 29/49002 Electrical device making

Abstract

Embodiments of compact micro-electro-mechanical systems (MEMS) devices are provided, as are embodiments of methods for fabricating MEMS devices. In one embodiment, the MEMS device includes a substrate, a movable structure resiliently coupled to the substrate, and an anchored structure fixedly coupled to the substrate. The movable structure includes a first plurality of movable fingers, and a second plurality of movable fingers electrically isolated from and interspersed with the first plurality of movable fingers. The anchored structure includes fixed fingers interspersed with first and second pluralities of movable fingers in a capacitor-forming relationship. First and second interconnects are electrically coupled to the first and second pluralities of movable fingers, respectively.

Claims

1. A microelectromechanical system (“

MEMS”

) device, comprising;

a substrate;

a movable structure resiliently coupled to the substrate, the movable structure comprising;

a first plurality of movable fingers; and

a second plurality of movable fingers electrically isolated from and interleaved with the first plurality of movable fingers to form a pattern of alternating first and second movable fingers in which a single one of the first movable fingers is positioned between a pair of the second movable fingers and a single one of the second movable fingers is positioned between a pair of the first movable fingers;

an anchored structure fixedly coupled to the substrate and including fixed fingers interspersed with the first and the second plurality of movable fingers in a capacitor-forming relationship; and

first and second interconnects electrically coupled to the first and the second plurality of movable fingers, respectively the second interconnect extending between the first interconnect and the first plurality of movable fingers; and

a plurality of cross-over features electrically coupling the first interconnect to the first plurality of movable fingers, while electrically isolating the first interconnect and the first plurality of movable fingers from the second interconnect.

2. A MEMS device according to claim 1 wherein the fixed fingers comprise:

a first plurality of fixed fingers; and

a second plurality of fixed fingers electrically isolated from and interspersed with the first plurality of fixed fingers, the first and the second plurality of fixed fingers distributed amongst the first and the second plurality of movable fingers in a laterally-spaced arrangement.

3. A MEMS device according to claim 2 wherein the first plurality of fixed fingers is electrically isolated from and interspersed with the second plurality of fixed fingers.

4. A MEMS device according to claim 2 further comprising:

a third interconnect electrically coupled to the first plurality of fixed fingers; and

a fourth interconnect electrically coupled to the second plurality of fixed fingers, the first, second, third, and fourth interconnects enabling monitoring of a first capacitance between the first plurality of fixed fingers and the first plurality of movable fingers, a second capacitance between the first plurality of fixed fingers and the second plurality of movable fingers, a third capacitance between the second plurality of fixed fingers and the first plurality of movable fingers, and a fourth capacitance between the second plurality of fixed fingers and the second plurality of movable fingers.

5. A MEMS device according to claim 4 wherein MEMS device comprises a wheatstone bridge formed, at least in part, by the first and the second plurality of movable fingers, the first and the second plurality of fixed fingers, and the first, second, third, and fourth interconnects.

6. A MEMS device according to claim 1 wherein the movable structure further comprises a plurality of electrical isolation features, each electrical isolation feature formed between a different neighboring pair of movable fingers.

7. A MEMS device according to claim 6 wherein the movable structure comprises an electrically-conductive body, and wherein the plurality of electrical isolation features comprise embedded electrical isolation features located between the electrically-conductive body of the movable structure.

8. A MEMS device according to claim 7 wherein the embedded electrical isolation features divide the electrically-conductive body of the movable structure into a plurality of electrically-isolated sections from each of which a different movable finger extends.

9. A MEMS device according to claim 7 wherein the embedded electrical isolation features mechanically join the first and the second plurality of movable fingers along a single plane.

10. A MEMS device according to claim 1 wherein a lateral distance between the centerlines of neighboring movable fingers is 9 microns or less.

11. A MEMS device according to claim 1 wherein the anchored structure comprises an elongated bridge, wherein the movable structure comprises a generally rectangular frame circumscribing the elongated bridge, and wherein the first and the second plurality of movable fingers extending inwardly from the generally rectangular frame toward the elongated bridge.

12. A microelectromechanical system (“

MEMS”

) device, comprising;

a substrate;

a movable structure formed over the substrate, the movable structure comprising;

a body resiliently coupled to the substrate;

a first plurality of movable fingers extending from the body; and

a second plurality of movable fingers extending from the body and interleaved with the first plurality of movable fingers to form a pattern of alternating first and second movable fingers in which a single one of the first movable fingers is positioned between a pair of the second movable fingers and a single one of the second movable fingers is positioned between a pair of the first movable fingers;

an anchored structure fixedly coupled to the substrate and including fixed fingers interspersed with the first and the second plurality of movable fingers in a capacitor-forming relationship; and

first and second interconnects electrically coupled to the first and the second plurality of movable fingers, respectively the second interconnect extending between the first interconnect and the first plurality of movable fingers; and

a plurality of cross-over features electrically coupling the first interconnect to the first plurality of movable fingers, while electrically isolating the first interconnect and the first plurality of movable fingers from the second interconnect.

13. A MEMS device according to claim 12 wherein the plurality of embedded electrical isolation features comprise a plurality of dielectric-filled trenches formed through the body of the movable structure.

14. A MEMS device according to claim 13 wherein the first and the second plurality of movable fingers are laterally mechanically joined by the plurality of dielectric-filled trenches.

15. A MEMS device according to claim 12 further comprising:

a first interconnect line formed over the body and electrically interconnecting the first plurality of movable fingers; and

a second interconnect line formed over the body and electrically interconnecting the second plurality of movable fingers.

16. A MEMS device according to claim 15 further comprising:

a first dielectric layer formed between the first interconnect line and the body; and

a second dielectric layer formed between the second interconnect line and the body.

17. A MEMS device according to claim 15 wherein the MEMS device comprises:

a structural layer in which the movable structure and the anchored structure are formed; and

an interconnect layer formed over the structure layer and containing the first and second interconnect lines.