MEMS and Method for Forming the Same

• US 20150353342A1
• Filed: 04/11/2013
• Published: 12/10/2015
• Est. Priority Date: 03/11/2013
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: Chang, Kuei-Sung, Wu, Ting-Hau
• Granted Patent: US 10,023,459 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B81B 3/001 Structures having a reduced contact area, e.g. with bumps or with a textured surface
• CPC Class Codes: B81B 3/0013 Structures dimensioned for mechanical prevention of stiction, e.g. spring with increased stiffness
• CPC Class Codes: B81B 3/0016 Arrangements for avoiding sticking of the flexible or moving parts not provided for in groups B81B3/0005 - B81B3/0013
• CPC Class Codes: B81C 1/00134 comprising flexible or deformable structures manufacture of MEMS devices for specific applications, see relevant places, e.g. gyroscopes G01C19/5719, pressure sensors G01L9/0042, accelerometers G01P15/0802, acoustic transducers or diaphragms therefor H04R31/00
• CPC Class Codes: B81C 1/00142 Bridges deformable micromirrors G02B26/0841
• CPC Class Codes: B81C 1/0015 Cantilevers switches using MEMS H01H1/0036; electrostatic relays using micromechanics H01H59/0009; microelectro-mechanical resonators H03H9/02244
• CPC Class Codes: B81C 1/0019 Flexible or deformable structures not provided for in groups B81C1/00142 - B81C1/00182
• CPC Class Codes: B81C 1/00468 Releasing structures
• CPC Class Codes: B81C 1/00484 Processes for releasing structures not provided for in group B81C1/00476
• CPC Class Codes: B81C 1/00936 Releasing the movable structure without liquid etchant
• CPC Class Codes: B81C 1/0096 For avoiding stiction when the device is in use, i.e. after manufacture has been completed
• CPC Class Codes: H01L 2924/1461 MEMS

Abstract

A method and apparatus are provided to prevent or reduce stiction of a MEMS device. The MEMS device may include a protrusion extending from a surface of the MEMS device. During manufacture, the protrusion may be connected across an opening in the MEMS device to a sidewall of the substrate. Before manufacture of the MEMS device is completed, at least a portion of the protrusion connecting the MEMS device to the substrate may be removed. During operation, the protrusion may provide stiction prevention or reduction for the surface from which the first protrusion may extend. A plurality of protrusions may be formed along a plurality of surfaces for the MEMS device to prevent or reduce stiction along the corresponding surfaces. Protrusions may also be formed on devices surrounding or encapsulating the MEMS device to prevent or reduce stiction of the MEMS device to the surrounding or encapsulating devices.

Claims

1. A method comprising:

forming a MEMS device in a first substrate, the MEMS device having a first surface;

forming a first protrusion in a first opening of the MEMS device to extend from the first surface of the MEMS device across the first opening to connect to a sidewall of the substrate adjacent to the MEMS device;

bonding the first substrate to a second substrate, the second substrate having a first surface; and

removing at least a portion of the first protrusion following the bonding the first substrate to the second substrate.

2. The method of claim 1, further comprising:

forming a second protrusion on the second substrate, wherein the second protrusion is opposite and separated from the first surface of the MEMS device.

3. The method of claim 1, further comprising:

forming a second protrusion in a second opening of the MEMS device to extend from a second surface of the MEMS device across the opening to connect to another sidewall of the substrate adjacent to the MEMS device.

4. The method of claim 3, wherein the second protrusion is opposite and separated from the second substrate.

5. The method of claim 3, further comprising:

removing at least a portion of the second protrusion connected to the first substrate following the bonding the first substrate to the second substrate.

6. The method of claim 1, further comprising:

forming a second protrusion to extend from a second surface of the MEMS device.

7. The method of claim 1, further comprising bonding a third substrate to the first substrate following the bonding the second substrate to the second substrate.

8. The method of claim 7, further comprising:

before bonding the third substrate to the first substrate, forming a second protrusion to extend from a second surface of the MEMS device, wherein the second surface is opposite the third substrate following the bonding the third substrate to the first substrate.

9. A method comprising:

forming a MEMS device in a first substrate, the MEMS device having a first surface, a second surface and a third surface;

forming a first protrusion to extend from the first surface of the MEMS device, a portion of the first protrusion connecting the MEMS device to a sidewall of the first substrate;

forming a second protrusion to extend from the second surface of the MEMS device;

bonding the first substrate to a second substrate, the second substrate having a first surface;

removing the portion of the first protrusion connecting the MEMS device to the first substrate following the bonding the first substrate to the second substrate, the removing allowing the MEMS device to move; and

bonding a third substrate to the first substrate, the third substrate having a first surface opposite the third surface of the MEMS device.

10. The method of claim 9, further comprising:

forming a third protrusion on the second substrate, wherein the third protrusion is separated from the second surface of the MEMS device.

11. The method of claim 9, further comprising:

forming a third protrusion to extend from a fourth surface of the MEMS device, a portion of the third protrusion connecting the MEMS device to another sidewall of the first substrate; and

removing the portion of the third protrusion connecting the MEMS device to the first substrate following the bonding the first substrate to the second substrate, the removing allowing the MEMS device to move.

12. The method of claim 9, further comprising:

forming a third protrusion to extend from the third surface of the MEMS device prior to the bonding the third substrate to the first substrate.

13. The method of claim 12, wherein the third protrusion has a portion connecting the MEMS device to another sidewall of the first substrate.

14. The method of claim 13, further comprising:

removing the portion of the third protrusion connecting the MEMS device to the first substrate following the bonding the first substrate to the second substrate, the removing allowing the MEMS device to move.

15. An apparatus comprising:

a first substrate having formed therein a MEMS device, the MEMS device having a first surface and a second surface;

a first protrusion extending from the first surface of the MEMS device, the first protrusion having a portion extending across an opening in the MEMS device;

a second substrate bonded to the first substrate, the second substrate having a first surface opposite the second surface of the MEMS device; and

a second protrusion extending from the first surface of the second substrate, the second protrusion having a first surface, wherein the first surface of the second protrusion is smaller than the second surface of the MEMS device.

16. The apparatus of claim 15, wherein the second protrusion is separated from the second surface of the MEMS device.

17. The apparatus of claim 15, wherein the first protrusion connects the MEMS device to a sidewall of the first substrate.

18. The apparatus of claim 15, further comprising:

a third protrusion extending from a third surface of the MEMS device, the third protrusion having a portion extending across another opening in the MEMS device to connect the MEMS device to another sidewall of the first substrate.

19. The apparatus of claim 15, further comprising:

a third protrusion extending from a third surface of the MEMS device, the third protrusion having a first surface, wherein the first surface of the third protrusion is smaller than the third surface of the MEMS device.

20. The apparatus of claim 19, wherein the third protrusion connects the MEMS device to a sidewall of the first substrate.