Preferentially deposited lubricant to prevent anti-stiction in micromechanical systems

• US 7,723,812 B2
• Filed: 11/02/2006
• Issued: 05/25/2010
• Est. Priority Date: 11/23/2005
• Status: Active Grant

• Current Assignee: Miradia Inc. (Walsin Lihwa Corporation)
• Original Assignee: Miradia Inc. (Walsin Lihwa Corporation)
• Inventors: Worley, Spencer, Chen, Dongmin, Xiong, Fulin
• Primary Examiner(s): Landau; Matthew C
• Assistant Examiner(s): Nicely; Joseph C
• Application Number:
  US11/556,145
• Publication Number:
  US 20070117244A1
• Time in Patent Office: 1,300 Days
• Field of Search: 257414-470, 257/632, 257/682, 257/684, 257/724, 257/729, 257/E25.004, 257/E27.122, 257/E27.127, 257/E27.129, 257/E29.167, 257/E31.001, 257/E31.032, 257/E31.037, 257/E31.11, 257/E31.119, 438/50, 438/51, 438/57, 438/58, 438/64, 438/66, 438/69, 438/73, 438/65, 438/761, 438/763, 359/230, 359/245, 359/290, 427/96.2, 427/96.5, 427/96.8
• US Class Current: 257/421
• 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: B81C 2201/112 Depositing an anti-stiction or passivation coating, e.g. on the elastic or moving parts
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites

Abstract

Embodiments of the present invention generally relate to a device that has an improved usable lifetime due to the presence of a lubricant that reduces the likelihood of stiction occurring between the various moving parts in an electromechanical device. Embodiments of the present invention also generally include a device, and a method of forming a device, that has one or more surfaces or regions that have a volume of lubricant disposed thereon that acts as a ready supply of “fresh” lubricant to prevent stiction occurring between interacting components found within the device. In one aspect, components within the volume of lubricant form a gas or vapor phase that reduces the chances of stiction-related failure in the formed device. In one example, aspects of this invention may be especially useful for fabricating and using micromechanical devices, such as MEMS devices, NEMS devices, or other similar thermal or fluidic devices.

Claims

1. A micromechanical device assembly, comprising:

one or more walls that form a processing region;

a storage surface that is disposed within the processing region;

a first contact surface disposed within the processing region;

a moveable component disposed within the processing region and having a second contact surface, wherein the second contact surface interacts with the first contact surface during device operation; and

a first lubricant layer disposed on the storage surface, and a second lubricant layer disposed on the first and second contact surfaces, wherein the first lubricant layer and the second lubricant layer are different in molecular composition,

wherein the first lubricant layer includes a plurality of lubricant molecules that form a stronger bond to the first and second contact surfaces relative to the storage surface and, during device operation, migrate away from the storage surface toward the first and second contact surfaces to be deposited onto the first and second contact surfaces.

2. The micromechanical device assembly of claim 1, further comprising a base member that has a first side that includes the first contact surface and the storage surface.

3. The micromechanical device assembly of claim 1, wherein the storage surface comprises a portion of one of the one or more walls.

4. The micromechanical device assembly of claim 1, wherein the lubricant molecules are attached to the storage surface through a head group that is bonded to the storage surface, wherein the storage surface comprises a material selected from a group consisting of silicon, silicon dioxide, titanium, aluminum and a glass material.

5. The micromechanical device assembly of claim 4, wherein the head group is selected from a group consisting of a oxysilane functional group, a trichlorosilane functional group and a carboxilate functional group.

6. The micromechanical device assembly of claim 1, further comprising a heating assembly that comprises:

a heating element that is in thermal communication with the storage surface; and

a controller that is adapted to adjust the temperature of the storage surface so that a portion of the lubricant layer disposed thereon can desorb into the processing region.

7. The micromechanical device assembly of claim 1, wherein one of the one or more walls is optically transparent and has a first side that contains the storage surface.

8. The micromechanical device assembly of claim 1, wherein the first lubricant layer comprises:

a plurality of first lubricant molecules, wherein each first lubricant molecule has a first head group that is adapted to bond to the storage surface and an end group; and

a plurality of second lubricant molecules, wherein each second lubricant molecule has a second head group that is adapted to bond to the end group,

wherein during device operation, a plurality of the second lubricant molecules migrate away from the storage surface toward the first and second contact surfaces to be deposited onto the first and second contact surfaces.

9. The micromechanical device assembly of claim 8, wherein each of the plurality of first lubricant molecules are cross-linked with each adjacent first lubricant molecule.

10. The micromechanical device assembly of claim 8, wherein each of the plurality of second lubricant molecules are cross-linked with each adjacent second lubricant molecule.

11. The micromechanical device assembly of claim 1, further comprising a channel formed in the at least one of the one or more walls, wherein the channel is in communication with an interior surface that contact the processing region and an exterior surface of the at least one of the one or more walls.

12. A micromechanical device assembly, comprising:

one or more walls that form a processing region, wherein at least a portion of one of the one or more walls is formed from an optically transparent material;

a storage surface that is disposed within the processing region;

a micromechanical device positioned within the processing region, wherein the micromechanical device includes;

a first contact surface disposed within the processing region,

a moveable component having a second contact surface and a conductive region,

an electrode coupled to a base, and

a power supply that is adapted to supply a sufficient electrical bias to the electrode relative to the conductive region to cause the moveable component to deflect relative to the base such that the first contact surface interacts with a second contact surface; and

a first lubricant layer disposed on the storage surface, and a second lubricant layer disposed on the first and second contact surfaces, wherein the first lubricant layer and the second lubricant layer are different in molecular composition,

wherein the first lubricant layer includes a plurality of lubricant molecules that form a stronger bond to the first and second contact surfaces relative to the storage surface and, during device operation, migrate away from the storage surface toward the first and second contact surfaces to be deposited onto the first and second contact surfaces.

13. The micromechanical device assembly of claim 12, wherein the base has a first side that includes the first contact surface and the storage surface.

14. The micromechanical device assembly of claim 12, wherein the storage surface comprises a portion of one of the one or more walls.

15. The micromechanical device assembly of claim 12, wherein the lubricant molecules are attached to the storage surface through a head group that is bonded to the storage surface, wherein the storage surface comprises a material selected from a group consisting of silicon, silicon dioxide, titanium, aluminum and a glass material.

16. The micromechanical device assembly of claim 15, wherein the head group is selected from a group consisting of a oxysilane functional group, a trichlorosilane functional group and a carboxilate functional group.

17. The micromechanical device assembly of claim 12, further comprising a heating assembly that comprises:

a heating element that is in thermal communication with the storage surface; and

a controller that is adapted to adjust the temperature of the storage surface so that a portion of the lubricant layer disposed thereon can desorb into the processing region.

18. The micromechanical device assembly of claim 12, wherein one of the one or more walls is optically transparent and has a first side that contains the storage surface.

19. The micromechanical device assembly of claim 12, wherein the first lubricant layer comprises:

a plurality of first lubricant molecules, wherein each first lubricant molecule has a first head group that is adapted to bond to the storage surface and an end group; and

a plurality of second lubricant molecules, wherein each second lubricant molecule has a second head group that is adapted to bond to the end group,

wherein during device operation, a plurality of the second lubricant molecules migrate away from the storage surface toward the first and second contact surfaces to be deposited onto the first and second contact surfaces.

20. The micromechanical device assembly of claim 19, wherein each of the plurality of first lubricant molecules are cross-linked with each adjacent first lubricant molecule.

21. The micromechanical device assembly of claim 19, wherein each of the plurality of second lubricant molecules are cross-linked with each adjacent second lubricant molecule.

22. 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, and the first contact surface interacts with the second contact surface during device operation;

an enclosure having one or more walls that form an operating region, wherein one of the one or more walls has a storage surface that is disposed within the operating region; and

a first lubricant layer disposed on the storage surface and a second lubricant layer disposed on the first and second contact surfaces, wherein the first lubricant layer and the second lubricant layer comprise different lubricant molecules

wherein during device operation, a plurality of lubricant molecules of the first lubricant layer migrate away from the storage surface toward the first and second contact surfaces to be deposited onto the first and second contact surfaces.

23. The micromechanical device assembly of claim 22, wherein the storage surface is a material selected from a group consisting of silicon, silicon dioxide, a glass material and aluminum.

24. The micromechanical device assembly of claim 22, wherein the head group is selected from a group consisting of a oxysilane functional group, a trichiorosilane functional group and a carboxilate functional group.

25. The micromechanical device assembly of claim 22, wherein the lubricant molecules of the first lubricant layer are adapted to desorb from the storage surface at operating temperatures of about 0°

C. and about 70°

C.

26. The micromechanical device assembly of claim 22, wherein the lubricant molecules of the first lubricant layer form a weaker bond with the storage surface and a stronger bond with the first or second contact surface.

27. The micromechanical device assembly of claim 22, further comprising a heating assembly that comprises:

a heating element that is in thermal communication with the storage surface; and

a controller that is adapted to adjust the temperature of the storage surface so that a portion of the first lubricant molecules disposed thereon can desorb into the processing region.

28. The micromechanical device assembly of claim 22, wherein one of the one or more walls is optically transparent and has a first side that contains the storage surface.