MICROELECTROMECHANICAL SYSTEMS DEVICES WITH IMPROVED LATERAL SENSITIVITY

• US 20150375989A1
• Filed: 06/27/2014
• Published: 12/31/2015
• Est. Priority Date: 06/27/2014
• Status: Active Grant

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Freescale Semiconductor, Inc. (NXP Semiconductors NV)
• Inventors: NAUMANN, Michael
• Granted Patent: US 9,612,254 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B81B 2207/095 through the lid
• CPC Class Codes: B81B 7/007 Interconnections between the MEMS and external electrical signals
• CPC Class Codes: B81C 1/00365 having low tensile stress between layers
• CPC Class Codes: B81C 2201/0197 Processes for making multi-layered devices not provided for in groups B81C2201/0176 - B81C2201/0192
• CPC Class Codes: B81C 2203/0136 Growing or depositing of a covering layer
• 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

Abstract

Microelectromechanical system (MEMS) devices and methods for forming MEMS devices are provided. The MEMS devices include a substrate, an anchored structure fixedly coupled to the substrate, and a movable structure resiliently coupled to the substrate. The movable structure has an opening formed therethrough and is positioned such that the anchored structure is at least partially within the opening and is in a capacitor-forming relationship with the movable structure. The movable structure comprises a movable structure finger extending only partially across the opening.

Claims

1. A microelectromechanical systems (MEMS) device comprising:

a substrate;

an anchored structure fixedly coupled to the substrate; and

a movable structure resiliently coupled to the substrate, the movable structure having an opening formed therethrough and being positioned such that the anchored structure is at least partially within the opening and is in a capacitor-forming relationship with the movable structure, wherein the movable structure comprises a movable structure finger extending only partially across the opening.

2. The MEMS device of claim 1, wherein the movable structure laterally surrounds the anchored structure.

3. The MEMS device of claim 1, wherein the movable structure comprises a first portion and a second portion, the second portion being on a side of the opening opposite the first portion, and wherein the movable structure finger extends from the first portion, into the opening, and towards the second portion.

4. The MEMS device of claim 3, wherein the anchored structure comprises an anchored structure finger in a capacitor-forming relationship with the movable structure finger.

5. The MEMS device of claim 4, wherein the anchored structure finger extends from the anchored structure towards the first portion of the movable structure.

6. The MEMS device of claim 5, wherein the movable structure further comprises a third portion and a fourth portion, the fourth portion being on a side of the opening opposite the third portion, and wherein the anchored structure further comprises a second anchored structure finger in a capacitor-forming relationship with the third portion of the movable structure.

7. The MEMS device of claim 6, wherein the movable structure finger is at least partially positioned between the anchored structure finger and the second anchored structure finger.

8. The MEMS device of claim 7, wherein a ratio of a distance between the movable structure finger and the anchored structure finger and a distance between the movable structure finger and the second anchored structure finger is between about 1:

2 and about 1;

4.

9. The MEMS device of claim 8, wherein the distance between the movable finger and the anchored structure finger is between about 1 micrometer (μ

m) and about 5 μ

m.

10. The MEMS device of claim 6, further comprising a second anchored structure fixedly coupled to the substrate, wherein the second anchored structure is at least partially within the opening, and wherein the movable structure comprises a second movable structure finger extending from the second portion of the movable structure, only partially across the opening, and towards the first portion of the movable structure, the second movable structure finger being in a capacitor-forming relationship with the second anchored structure.

11. A microelectromechanical systems (MEMS) device comprising:

a substrate;

a first anchored structure fixedly coupled to the substrate and comprising a first anchored structure finger;

a second anchored structure fixedly coupled to the substrate and comprising a second anchored structure finger; and

a movable structure resiliently coupled to the substrate, the movable structure having an opening formed therethrough and being positioned such that the first anchored structure and the second anchored structure are at least partially within the opening and are laterally surrounded by the movable structure, wherein the movable structure comprises;

a first movable structure finger extending only partially across the opening and being in a capacitor-forming relationship with the first anchored structure finger; and

a second movable structure finger extending only partially across the opening and being in a capacitor-forming relationship with the second anchored structure finger.

12. The MEMS device of claim 11, wherein the movable structure further comprises a first portion, a second portion, a third portion, and a fourth portion, the second portion being on a side of the opening opposite the first portion and the fourth portion being on a side of the opening opposite the third portion, and

wherein the first movable structure finger extends from the first portion of the movable structure, into the opening, and towards the second portion, and the second movable structure finger extends from the second portion of the movable structure, into the opening, and towards the first portion.

13. The MEMS device of claim 12, wherein the first anchored structure further comprises a third anchored structure finger, the third anchored structure finger being in a capacitor-forming relationship with the third portion of the movable structure, and

wherein the second anchored structure further comprises a fourth anchored structure finger, the fourth anchored structure finger being in a capacitor-forming relationship with the fourth portion of the movable structure.

14. The MEMS device of claim 13, wherein the first movable structure finger is at least partially positioned between the first anchored structure finger and the third anchored structure finger, and

wherein the second movable structure finger is at least partially positioned between the second anchored structure finger and the fourth anchored structure finger.

15. The MEMS device of claim 14, wherein a ratio of a distance between the first movable structure finger and the first anchored structure finger and a distance between the first movable structure finger and the third anchored structure finger is between about 1:

2 and about 1;

4, and wherein a ratio of the distance between the second movable structure finger and the second anchored structure finger and the distance between the second movable structure finger and the fourth anchored structure finger is between about 1;

2 and about 1;

4.

16. A method for determining a force with a microelectromechanical (MEMS) system device, the method comprising:

detecting a change in capacitance between an anchored structure fixedly coupled to a substrate and a finger of a movable structure resiliently coupled to the substrate, the movable structure having an opening and being positioned such that the anchored structure is at least partially within the opening, the finger of the movable structure extending only partially across the opening; and

determining the force based on the detected change in capacitance.

17. The method of claim 16, wherein the movable structure comprises a first portion and a second portion, the second portion being on a side of the opening opposite the first portion, and wherein the finger extends from the first portion, into the opening, and towards the second portion, and wherein the anchored structure comprises a second finger in a capacitor-forming relationship with the finger.

18. The method of claim 17, wherein the movable structure further comprises a third portion and a fourth portion, the fourth portion being on a side of the opening opposite the third portion, and wherein the anchored structure further comprises a third finger in a capacitor-forming relationship with the third portion of the movable structure.

19. The method of claim 18, wherein the finger is at least partially positioned between the second finger and the third finger.

20. The method of claim 19, wherein a ratio of a distance between the finger and the second finger and a distance between the finger and the third finger is between about 1:

2 and about 1;

4.