MEMS method and structure

• US 9,394,164 B2
• Filed: 03/14/2013
• Issued: 07/19/2016
• 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): Smoot, Stephen W
• Assistant Examiner(s): Chin, Edward
• Application Number:
  US13/827,928
• Publication Number:
  US 20140264644A1
• Time in Patent Office: 1,223 Days
• Field of Search: 257/E21.158, 257/414, 257/415, 438/669
• US Class Current: 1/1
• 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;

patterning the locker film to form a patterned locker film, wherein the patterned locker film extends from the moveable mass region to the support region and wherein the moveable mass region is at least partially exposed by the patterning the locker film;

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

removing at least a portion of the patterned 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 removing at least a portion of the patterned 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 and at least one metallization layer located over the active devices;

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 and the at least one metallization layer located between the first substrate and the second 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 method of manufacturing a semiconductor device, the method comprising:

covering a first region of a first substrate with a holding layer, the first substrate further comprising a second region on a first side of the first region and a third region on an opposite side of the first region, the first region extending from a first surface of the first substrate to a second surface of the first substrate opposite the first surface;

removing the first region to expose a first sidewall of the second region and a second sidewall of the third region, wherein the removing the first region is performed while the holding layer is covering the first region; and

removing a first portion of the holding layer after the removing the first region, the first portion extending from a third surface of the holding layer to a fourth surface of the holding layer opposite the third surface, wherein after the removing the first portion the third surface is aligned with the first sidewall and the fourth surface is aligned with the second sidewall.

16. The method of claim 15, further comprising removing a second portion of the holding layer after the removing the first portion of the holding layer, wherein the removing the second portion of the holding layer is performed at least in part with a different process than the removing the first portion of the holding layer.

17. The method of claim 16, wherein the removing the second portion of the holding layer is performed at least in part with an ashing process.

18. The method of claim 16, wherein the removing the second portion of the holding layer is performed at least in part with a wet etch process.

19. The method of claim 15, further comprising bonding the first substrate to a second substrate prior to the removing the first region.

20. The method of claim 15, wherein the covering the first region of the first substrate with the holding layer further comprises forming a layer of amorphous carbon.