Anti-stiction gas-phase lubricant for micromechanical systems

• US 7,580,174 B2
• Filed: 12/22/2005
• Issued: 08/25/2009
• Est. Priority Date: 11/23/2005
• Status: Active Grant

• Current Assignee: Miradia Inc. (Walsin Lihwa Corporation)
• Original Assignee: Miradia Inc. (Walsin Lihwa Corporation)
• Inventors: Chen, Dongmin, Xiong, Fulin
• Primary Examiner(s): Sugarman; Scott J
• Assistant Examiner(s): Thomas; Brandi N
• Application Number:
  US11/315,607
• Publication Number:
  US 20070114882A1
• Time in Patent Office: 1,342 Days
• Field of Search: 359/290, 359/291, 359/292, 359/295, 359/298
• US Class Current: 359/290
• CPC Class Codes: B81B 2201/042 Micromirrors, not used as optical switches
• CPC Class Codes: B81B 3/0005 Anti-stiction coatings
• 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: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: G02B 26/0833 the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD G02B26/0825 takes precedence; micromechanical devices in general B81B
• CPC Class Codes: H02N 1/006 of the gap-closing type H02N1/004 takes precedence

Abstract

One embodiment of an micromechanical device includes a first contact surface, a moveable component having a second contact surface, where the second contact surface interacts with the first contact surface during device operation, and a gas-phase lubricant disposed between the first contact surface and the second contact surface, where the gas-phase lubricant is adapted to reduce stiction-related forces between the first contact surface and the second contact surface. One advantage of the disclosed device is that a gas-phase lubricant has a high diffusion rate and, therefore, is self-replenishing, meaning that it can quickly move back into a contact region after being physically displaced from the region by the contacting surfaces of the device during operation. Consequently, the gas-phase lubricant is more reliable than conventional solid or liquid lubricants in preventing stiction-related device failures.

Claims

1. A micromechanical device assembly comprising:

a moveable component having a first contact surface;

a second contact surface, wherein the first contact surface of the moveable component interacts with the second contact surface during device operation;

an enclosure having one or more walls that form an operating region; and

a gas-phase lubricant disposed in the operating region between the first contact surface and the second contact surface, wherein the gas-phase lubricant is adapted to adsorb on the surface of the first or second contact surface during device operation to reduce stiction-related forces between the first contact surface and the second contact surface,

wherein the gas-phase lubricant adsorbed on the first or second contact surface during device operation has a surface energy that is lower than the surface energy of the first or second contact surface.

2. The micromechanical device assembly of claim 1, wherein the second contact surface is a region of a base component that is positioned within the operating region.

3. The micromechanical device assembly of claim 1, wherein the second contact surface is a region on one of the one or more walls of the enclosure.

4. The micromechanical device assembly of claim 1, wherein the gas-phase lubricant is a fluorinated compound that has a molecular weight greater than about 100 amu.

5. The micromechanical device assembly of claim 1, wherein the gas-phase lubricant is adapted to reduce friction between contacting surfaces.

6. The micromechanical device assembly of claim 1, wherein the gas-phase lubricant has a viscosity between about 10 and about 100 micropoise.

7. The micromechanical device assembly of claim 1, wherein the gas-phase lubricant does not react with the materials from which the first or second contact surfaces are made during device operation.

8. The micromechanical device assembly of claim 1, wherein the gas-phase lubricant is hydrophobic.

9. The micromechanical device assembly of claim 1, wherein the gas-phase lubricant exists in a gaseous state at temperature between about 0°

C. and about 70°

C. and a pressure up to about 800 Torr.

10. The micromechanical device assembly of claim 1, wherein the gas-phase lubricant exists in a gaseous state at temperatures between about 0°

C. and about 40°

C.

11. The micromechanical device assembly of claim 1, wherein the gas-phase lubricant exists in a gaseous state when it is introduced into the operating region.

12. The micromechanical device assembly of claim 1, wherein the gas-phase lubricant exists in a gaseous state at temperatures between about 0°

C. and about 70°

C.

13. The micromechanical device assembly of claim 1, wherein the gas-phase lubricant forms a monolayer on the first and second surfaces when they are at a temperature between about 0°

C. and about 70°

C. and a pressure of gas-phase lubricant disposed between the first contact surface and the second contact surface is up to about 800 Torr.

14. The micromechanical device assembly of claim 1, wherein the gas-phase lubricant repairs a solid or liquid lubricant layer on the first or second contact surfaces under normal operating conditions.

15. The micromechanical device assembly of claim 1, wherein the gas-phase lubricant is non-polar.

16. The micromechanical device assembly of claim 1, wherein the gas-phase lubricant is selected so that it will not breakdown due to the exposure to optical radiation.

17. The micromechanical device assembly of claim 1, wherein the gas-phase lubricant is selected so that it will not ionize in an electric field up to about 300 Volts/μ

m.

18. The micromechanical device assembly of claim 1, wherein the gas-phase lubricant has permittivity greater than argon, nitrogen and air.

19. A micromechanical device assembly comprising:

a moveable component having a first contact surface;

a second contact surface, wherein the moveable component interacts with the second contact surface during device operation;

an enclosure having one or more walls that form an operating region; and

a gas-phase lubricant disposed in the operating region between the first contact surface and the second contact surface, wherein the gas-phase lubricant is a fluorinated compound having a molecular weight greater than about 100 amu that adsorbs on the surface of the first or second contact surface during device operation,

wherein the gas-phase lubricant adsorbed on the first or second contact surface during device operation has a surface energy that is lower than the surface energy of the first or second contact surface.

20. A micromechanical device assembly comprising:

a moveable component having a first contact surface;

a second contact surface, wherein the moveable component interacts with the second contact surface during device operation;

an enclosure having one or more walls that form an operating region; and

a gas-phase lubricant disposed in the operating region between the first contact surface and the second contact surface, wherein the gas-phase lubricant is a hydrophobic compound that adsorbs on the surface of the first or second contact surface during device operation,

wherein the gas-phase lubricant adsorbed on the first or second contact surface during device operation has a surface energy that is lower than the surface energy of the first or second contact surface.