MEMS method and structure

• US 10,160,642 B2
• Filed: 07/18/2016
• Issued: 12/25/2018
• Est. Priority Date: 03/12/2013
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: Wu, Ting-Hau, Chang, Kuei-Sung
• Primary Examiner(s): Chin, Edward
• Application Number:
  US15/212,827
• Publication Number:
  US 20160325988A1
• Time in Patent Office: 890 Days
• Field of Search: 257E21158, 257414, 257415, 438669
• CPC Class Codes: B81B 2201/0235 Accelerometers
• CPC Class Codes: B81B 2207/012 the micromechanical device and the control or processing electronics being separate parts in the same package
• CPC Class Codes: B81B 2207/015 the micromechanical device and the control or processing electronics being integrated on the same substrate
• CPC Class Codes: B81B 3/0021 Transducers for transforming electrical into mechanical energy or vice versa dynamo-electric machines H02K99/00; electrostatic machines H02N1/00; piezoelectric devices H10N30/00
• CPC Class Codes: B81C 1/00587 Processes for avoiding or controlling over-etching not provided for in B81C1/00571 - B81C1/00579
• CPC Class Codes: B81C 1/00801 Avoid alteration of functional structures by etching, e.g. using a passivation layer or an etch stop layer B81C1/00595, B81C1/00468 take precedence
• CPC Class Codes: B81C 2201/0132 Dry etching, i.e. plasma etching, barrel etching, reactive ion etching [RIE], sputter etching or ion milling
• CPC Class Codes: B81C 2201/0133 Wet etching
• CPC Class Codes: B81C 2203/036 Fusion bonding

Abstract

MEMS structures and methods utilizing a locker film are provided. In an embodiment a locker film is utilized to hold and support a moveable mass region during the release of the moveable mass region from a surrounding substrate. By providing additional support during the release of the moveable mass, the locker film can reduce the amount of undesired movement that can occur during the release of the moveable mass, and preventing undesired etching of the sidewalls of the moveable mass.

Claims

1. A microelectromechanical structure comprising:

a moveable mass separated from a support region by an opening, the moveable mass being moveable relative to the support region, the opening extending through the moveable mass from a first surface of the moveable mass to an opposing second surface of the moveable mass, the opening exposing a sidewall of the moveable mass and a sidewall of the support region;

a first support film extending along and contacting the first surface of the moveable mass, the first support film having a first edge aligned with the sidewall of the moveable mass and having a second edge opposite the first edge, wherein the second edge intersects the first surface of the moveable mass, the first surface of the moveable mass being perpendicular to the sidewall of the moveable mass, wherein the first support film covers a first portion of the first surface of the moveable mass while exposing a second portion of the first surface of the moveable mass; and

a second support film located on the support region, the second support film having a second edge aligned with the sidewall of the support region, wherein the first support film and the second support film comprise a same material.

2. The microelectromechanical structure of claim 1, wherein the same material is an oxide.

3. The microelectromechanical structure of claim 1, wherein the same material is silicon carbide.

4. The microelectromechanical structure of claim 1, wherein the same material is polysilicon.

5. The microelectromechanical structure of claim 1, wherein the microelectromechanical structure further comprises a support substrate bonded to the support region.

20. The microelectromechanical structure of claim 5, wherein the first support film is disposed between the moveable mass and the support substrate.

6. A microelectromechanical structure comprising:

a moveable mass region;

a support region;

a support substrate bonded to the support region; and

a locking material comprising;

a first portion in physical contact with a first surface of the moveable mass region, wherein a portion of the first surface of the moveable mass region is uncovered by the locking material, wherein the first portion is located between the moveable mass region and the support substrate;

a second portion in physical contact with a first surface of the support region, wherein a portion of the first surface of the support region is uncovered by the locking material; and

an opening between the first portion and the second portion, the opening allowing the moveable mass region to move relative to the support region.

7. The microelectromechanical structure of claim 6, wherein the support substrate is electrically connected to the support region.

8. The microelectromechanical structure of claim 7, wherein the support substrate is a control substrate.

9. The microelectromechanical structure of claim 7, wherein the support substrate comprises:

a semiconductor substrate; and

metallization layers located between the semiconductor substrate and the moveable mass region.

10. The microelectromechanical structure of claim 6, wherein the locking material is an oxide.

11. The microelectromechanical structure of claim 6, wherein the locking material is silicon carbide.

12. The microelectromechanical structure of claim 6, wherein the locking material is silicon.

13. A microelectromechanical device comprising:

a locking material;

a first opening through the locking material, wherein the first opening has a first sidewall and a second sidewall opposite the first sidewall;

a moveable mass with a third sidewall aligned with the second sidewall, wherein the moveable mass has a planar surface contacting the locking material, the planar surface having a first portion and a second portion, wherein the locking material exposes the first portion of the planar surface while covering the second portion of the planar surface;

a support mass with a fourth sidewall aligned with the first sidewall; and

a substrate bonded to and electrically connected to the support mass, wherein the locking material is disposed between the substrate and the moveable mass.

14. The microelectromechanical device of claim 13, further comprising a second opening through the locking material, wherein the second opening has a fifth sidewall and a sixth sidewall opposite the fifth sidewall.

15. The microelectromechanical device of claim 14, wherein the moveable mass has a seventh sidewall aligned with the fifth sidewall.

16. The microelectromechanical device of claim 15, wherein the support mass has an eighth sidewall aligned with the sixth sidewall.

17. The microelectromechanical device of claim 13, wherein the substrate is a control substrate.

18. The microelectromechanical device of claim 13, wherein the locking material is silicon.

19. The microelectromechanical device of claim 13, wherein the locking material is silicon carbide.