Coating for optical MEMS devices

• US 7,009,745 B2
• Filed: 10/31/2003
• Issued: 03/07/2006
• Est. Priority Date: 10/31/2002
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Jacobs, Simon Joshua, Miller, Seth A.
• Primary Examiner(s): Phan, James
• Application Number:
  US10/699,410
• Publication Number:
  US 20040136044A1
• Time in Patent Office: 858 Days
• Field of Search: 359196-227, 359/230, 359/290, 359/298, 359/838, 359846-848, 359/850, 359855-857, 359871-872, 359/896, 359/900, 359/580, 359/582, 359/584
• US Class Current: 359/223.1
• CPC Class Codes: B81B 2201/042 Micromirrors, not used as optical switches
• CPC Class Codes: B81B 3/0005 Anti-stiction coatings
• CPC Class Codes: B81B 3/0083 Optical properties
• 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: G02B 1/115 Multilayers
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: Y10S 359/90 Methods

Abstract

A micromechanical device having a deflectable member which contacts a stationary member. An antireflective coating is applied to portions of the micromechanical device to limit undesired reflection from the device. A passivation or lubrication layer is applied to the device to reduce stiction between the deflectable member and the stationary member. An insulator layer is utilized between the antireflective coating and the lubrication layer to prevent photoelectric-induced breakdown of the lubrication layer.

Claims

1. A method of forming a coating comprising:

providing a substrate having a metal layer;

applying an antireflective layer to said substrate layer;

applying an insulator layer to said antireflective layer; and

applying a lubrication layer to said insulator layer.

2. The method of claim 1, said applying an insulator comprising:

applying an oxide layer over said antireflective layer.

3. The method of claim 1, said applying an insulator comprising:

applying an oxide layer over said antireflective layer using plasma deposition.

4. The method of claim 1, said providing comprising:

providing a partially fabricated micromechanical device.

5. The method of claim 1, said providing comprising:

providing a partially fabricated micromechanical device having an electrode.

6. The method of claim 1, said providing comprising:

providing a partially fabricated micromechanical device having an aluminum alloy electrode.

7. The method of claim 1, said providing comprising:

providing a partially fabricated micromirror device comprising an aluminum alloy landing electrode supported by a semiconductor substrate.

8. The method of claim 7, said applying an antireflective coating comprising:

applying a titanium nitride coating to said landing electrode.

9. The method of claim 8, said applying an insulator layer comprising:

applying an oxide layer over said titanium nitride coating.

10. The method of claim 8, said applying an insulator layer comprising:

applying an oxide layer over said titanium nitride coating using plasma deposition.

11. The method of claim 8, said applying an insulator layer comprising:

growing a thermal oxide layer over said titanium nitride coating.

12. The method of claim 9, said applying a lubrication layer comprising:

applying a halogenated acid layer to said oxide layer.

13. The method of claim 9, said applying a lubrication layer comprising:

applying a perfluorodecanoic acid layer to said oxide layer.

14. The method of claim 1, said applying an insulator layer comprising:

applying a metal layer over said antireflective layer; and

oxidizing said metal layer.

15. The method of claim 1, said applying an insulator layer comprising:

applying a metal layer no thicker than 200 Å

over said antireflective layer; and

oxidizing said metal layer.

16. The method of claim 1, said applying an insulator layer comprising:

applying a metal layer no thicker than 100 Å

over said antireflective layer; and

oxidizing said metal layer.

17. The method of claim 1, said applying an insulator layer comprising:

applying an aluminum layer no thicker than 100 Å

over said antireflective layer; and

oxidizing said metal layer.

18. The method of claim 1, said applying a lubrication layer comprising:

applying a halogenated acid layer to said insulator layer.

19. The method of claim 1, said applying a lubrication layer comprising:

applying a perfluorodecanoic acid layer to said insulator layer.

20. A micromechanical device comprising:

a substrate;

a reflective member supported on said substrate;

an antireflective coating supported on said reflective member;

an insulator layer supported on said antireflective coating; and

a lubrication layer supported on said insulator layer.

21. The micromechancial device of claim 20, said substrate comprising:

a silicon substrate.

22. The micromechanical device of claim 20, said reflective member comprising:

an aluminum alloy member supported on said substrate.

23. The micromechanical device of claim 20, said reflective member comprising:

an aluminum alloy landing electrode supported on said substrate.

24. The micromechanical device of claim 20, said antireflective coating comprising:

a titanium nitride coating supported on said reflective member.

25. The micromechanical device of claim 20, said insulator layer comprising:

an oxide layer supported on said antireflective coating.

26. The micromechanical device of claim 20, said insulator layer comprising:

an oxide layer plasma deposited on said antireflective coating.

27. The micromechanical device of claim 20, said insulator layer comprising:

an thermal oxide layer grown on said antireflective coating.

28. The micromechanical device of claim 20, said lubrication layer comprising:

a halogenated acid layer supported on said insulator layer.

29. The micromechanical device of claim 20, said lubrication layer comprising:

a perfluorodecanoic acid layer supported on said insulator layer.

30. A system comprising:

a light source for providing a beam of light along a light path; and

a device on said light path, said device comprising;

a substrate;

a reflective layer;

an antireflective coating supported on said reflective layer;

an insulation layer supported on said antireflective coating; and

a lubrication layer on said insulation layer.

31. The system of claim 30, said substrate comprising:

a silicon substrate.

32. The system of claim 30, said reflective member comprising:

an aluminum alloy member supported on said substrate.

33. The system of claim 30, said reflective member comprising:

an aluminum alloy landing electrode supported on said substrate.

34. The system of claim 30, said antireflective coating comprising:

a titanium nitride coating supported on said reflective layer.

35. The system of claim 30, said insulator layer comprising:

an oxide layer supported on said antireflective coating.

36. The system of claim 30, said insulator layer comprising:

an oxide layer plasma deposited on said antireflective coating.

37. The system of claim 30, said insulator layer comprising:

an thermal oxide layer grown on said antireflective coating.

38. The system of claim 30, said lubrication layer comprising:

a halogenated acid layer supported on said insulator layer.

39. The system of claim 30, said lubrication layer comprising:

a perfluorodecanoic acid layer supported on said insulator layer.