MICROELECTROMECHANICAL SYSTEMS DEVICES AND METHODS FOR THE FABRICATION THEREOF

• US 20130283913A1
• Filed: 04/27/2012
• Published: 10/31/2013
• 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: Jo, Sung Jin, Zhang, Lisa Z., Lin, Yizhen
• Granted Patent: US 9,003,886 B2
• Time in Patent Office: Days
• 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 interspersed with the first plurality of movable fingers;

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

first and second interconnects electrically coupled to the first and second pluralities of movable fingers, respectively.

2. A MEMS device according to claim 1 wherein second plurality of movable fingers is interleaved with the first plurality of movable fingers in an alternating arrangement.

3. A MEMS device according to claim 1 wherein the second interconnect extends between the first interconnect and the first plurality of movable fingers, and wherein the MEMS device further comprises 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.

4. 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 second pluralities of fixed fingers distributed amongst the first and second pluralities of movable fingers in a laterally-spaced arrangement.

5. A MEMS device according to claim 4 wherein the first plurality of fixed fingers is electrically isolated from and interspersed with the second plurality of fixed fingers.

6. A MEMS device according to claim 4 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.

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

8. 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.

9. A MEMS device according to claim 8 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.

10. A MEMS device according to claim 9 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.

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

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

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

14. 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;

first and second pluralities of interleaved movable fingers extending from the body; and

a plurality of embedded electrical isolation features formed in the body and electrically isolating neighboring ones of the first and second plurality of interleaved movable fingers; and

an anchored structure fixedly coupled to the substrate and including a plurality of fixed fingers interspersed with the first an second pluralities of interleaved movable fingers.

15. A MEMS device according to claim 14 wherein plurality of embedded electrical isolation features comprise a plurality of dielectric-filled trenches formed through the body of the movable structure.

16. A MEMS device according to claim 15 wherein the first and second plurality of interleaved movable fingers are laterally mechanically joined by the plurality of dielectric-filled trenches.

17. A MEMS device according to claim 14 further comprising:

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

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

18. A MEMS device according to claim 17 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.

19. A MEMS device according to claim 17 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.

20. A method for manufacturing a microelectromechanical system (“

MEMS”

) device, the method comprising;

forming a movable structure over a substrate, the movable structure including 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;

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

forming first and second interconnect lines over the movable structure and the anchored structure electrically coupled to the first and second plurality of movable fingers, respectively.