MEMS Method and Structure

• US 20140264644A1
• Filed: 03/14/2013
• Published: 09/18/2014
• 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
• Granted Patent: US 9,394,164 B2
• Time in Patent Office: Days
• US Class Current: 257/415
• 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 method of manufacturing a microelectromechanical structure, the method comprising:

forming a locker film on a first surface of a first substrate, the first substrate comprising a moveable mass region and a support region;

etching through the first substrate to release the moveable mass region from the support region, the etching stopping on the locker film; and

removing at least a portion of the locker film to release the moveable mass region.

2. The method of claim 1, further comprising bonding the first substrate to a second substrate prior to the etching through the first substrate.

3. The method of claim 2, wherein the bonding the first substrate to the second substrate is performed at least in part through fusion bonding.

4. The method of claim 1, wherein the locker film is an oxide.

5. The method of claim 1, wherein the etching through the first substrate is performed at least in part using a deep reactive ion etch.

6. The method of claim 1, wherein the locker film comprises a sacrificial material.

7. The method of claim 1, wherein the etching through the locker film removes the locker film.

8. A method of manufacturing a microelectromechanical structure, the method comprising:

providing a first substrate with active devices located in the first substrate;

forming a support film on a first surface of a second substrate;

bonding the first substrate to the second substrate, the first surface facing the first substrate;

releasing a moveable mass region within the second substrate, while supporting the moveable mass region with the support film; and

removing at least a portion of the support film to remove the support of the support film.

9. The method of claim 8, wherein the bonding the first substrate to the second substrate is performed at least in part with fusion bonding.

10. The method of claim 8, wherein the support film is an oxide.

11. The method of claim 8, wherein the support film is a sacrificial material.

12. The method of claim 11, wherein the sacrificial material is amorphous carbon.

13. The method of claim 8, wherein the removing at least a portion of the support film removes all of the support film from the first substrate.

14. The method of claim 8, wherein the releasing the moveable mass region is performed at least in part using a deep reactive ion etching process.

15. A microelectromechanical structure comprising:

a moveable mass separated from a support region, the moveable mass being moveable relative to a support region;

a first support film located on the moveable mass, the first support film having a first edge aligned with an edge of the moveable mass; and

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

16. The microelectromechanical structure of claim 15, wherein the first support film and the second support film comprise the same material.

17. The microelectromechanical structure of claim 16, wherein the same material is an oxide.

18. The microelectromechanical structure of claim 16, wherein the same material is silicon carbide.

19. The microelectromechanical structure of claim 16, wherein the same material is polysilicon.

20. The microelectromechanical structure of claim 15, wherein the microelectromechanical structure further comprises a support substrate bonded to the support region.