System and method of providing MEMS device with anti-stiction coating

• US 20060077503A1
• Filed: 04/29/2005
• Published: 04/13/2006
• Est. Priority Date: 09/27/2004
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Gally, Brian J., Palmateer, Lauren, Cummings, William J.
• Granted Patent: US 7,692,839 B2
• Time in Patent Office: Days
• US Class Current: 359/237
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: G02B 26/001 based on interference in an adjustable optical cavity interference filters G02B5/28; devices or arrangements using multiple reflections in spectrometry or monochromators G01J3/26

Abstract

In various embodiments of the invention, an anti-stiction coating is formed on at least one surface of an interior cavity of a MEMS device. Particular embodiments provide an anti-stiction on one or mirror surfaces of an interferometric light modulation device, also known as an iMoD in some embodiments. In other embodiments, an interferometric light modulation device is encapsulated within a package and the anti-stiction coating is applied after the package is fabricated. In one embodiment, one or more orifices are defined in the package, e.g., in a seal, a substrate or a backplate and the anti-stiction coating material is supplied into the interior of the package via the orifice(s). In one embodiment, the anti-stiction coating material includes a self-aligned (or self-assembled) monolayer. In yet another embodiment, the anti-stiction layer coating can be incorporated into a release process where a sacrificial layer of an interferometric light modulation device is etched away with the use of a gas.

Claims

1. An interferometric light modulating device, comprising:

a reflective element;

a transmissive element; and

an anti-stiction coating located between at least a portion of said reflective element and said transmissive element.

2. The device of claim 1, further comprising a transparent substrate, wherein said substrate is adhered to a backplate with a seal to form a sealed package, and wherein said reflective element, said transmissive element and said anti-stiction coating are located within said sealed package.

3. The device of claim 2, further comprising a desiccant, wherein said desiccant is located within said sealed package.

4. The device of claim 1, wherein said anti-stiction coating comprises a self-aligning monolayer.

5. The device of claim 1, wherein said anti-stiction coating is selected from the group consisting of:

teflon, perfluorodecanoic carboxylic acid, octadecyltrichlorosilane (OTS), dichlorodimethylsilane, fluoro silane, chloro-fluoro silane, methoxy silane, trichlorosilane, silicone, polystyrene, polyurethane, a block copolymer containing a hydrophobic component, polysilazane, graphite, diamond-like carbide (DLC), silicon carbide (SiC), hydrogenated diamond coating, and fluorinated DLC.

6. The device of claim 2, further comprising at least one orifice in said package.

7. The device of claim 6, wherein said at least one orifice is an orifice in said seal, said substrate or said backplate.

8. The device of claim 1, wherein said anti-stiction coating is provided on at least a portion of said reflective element.

9. The device of claim 1, wherein said anti-stiction coating is provided on at least a portion of said transmissive element.

10. The device of claim 1, further comprising a sacrificial layer located between said reflective element and said transmissive element, wherein said anti-stiction coating is provided on at least a portion of said sacrificial layer.

11. A method for manufacturing an interferometric light modulating device, comprising:

providing a transmissive element;

providing a reflective element; and

providing an anti-stiction coating, wherein said anti-stiction coating is located between at least a portion of said reflective element and said transmissive element.

12. The method of claim 11, further comprising:

providing a sacrificial layer located between said reflective element and said transmissive element; and

etching at least a portion of the sacrificial material prior to providing an anti-stiction coating.

13. The method of claim 11, further comprising:

providing a sacrificial layer located between said reflective element and said transmissive element, wherein said anti-stiction coating is provided on at least a portion of said sacrificial layer.

14. The method of claim 11, further comprising:

providing a transparent substrate;

providing a seal;

providing a backplate; and

adhering said substrate and said backplate with said seal, wherein said reflective element, said transmissive element, and said anti-stiction coating are located between said substrate and said backplate.

15. The method of claim 14, wherein said steps of providing a substrate, seal and a backplate, and adhering said substrate and said backplate with said seal occur prior to said step of providing an anti-stiction coating.

16. The method of claim 14, wherein said step of providing an anti-stiction coating occurs prior to said step of adhering said substrate and said backplate with said seal.

17. The method of claim 14, wherein said seal, said substrate or said backplate have at least one orifice for providing said anti-stiction coating.

18. The method of claim 14, further comprising providing a desiccant, wherein said desiccant is located between said substrate and said backplate.

19. The method of claim 11, wherein said anti-stiction coating comprises a self-aligning monolayer.

20. The method of claim 11, wherein said anti-stiction coating is selected from the group consisting of:

teflon, perfluorodecanoic carboxylic acid, octadecyltrichlorosilane (OTS), dichlorodimethylsilane, fluoro silane, chloro-fluoro silane, methoxy silane, trichlorosilane, silicone, polystyrene, polyurethane, a block copolymer containing a hydrophobic component, polysilazane, graphite, diamond-like carbide (DLC), silicon carbide (SiC), hydrogenated diamond coating, and fluorinated DLC.

21. The method of claim 11, wherein said anti-stiction coating is providing on at least a portion of said reflective element.

22. The method of claim 11, wherein said anti-stiction coating is providing on at least a portion of said transmissive element.

23. An interferometric light modulating device, comprising:

a reflective element;

a transmissive element; and

means for reducing attractive forces between said reflective element and said transmissive element.

24. The device of claim 23, further comprising a transparent substrate, wherein said substrate is adhered to a backplate with a seal to form a sealed package, and wherein said reflective element and said transmissive element are located within said sealed package.

25. The device of claim 24, further comprising a desiccant, wherein said desiccant is located within said sealed package.

26. The device of claim 23, wherein said means for reducing attractive forces comprises an anti-stiction coating on at least a portion of said reflective element.

27. The device of claim 23, wherein said means for reducing attractive forces comprises applying an anti-stiction coating to at least a portion of said transmissive element.

28. The device of claim 23, further comprising a sacrificial layer located between said reflective element and said transmissive element, wherein said means for reducing attractive forces comprises applying an anti-stiction coating to at least a portion of said sacrificial layer.

29. An interferometric light modulating device provided by a method of manufacturing, comprising:

providing a reflective element;

providing a transmissive element; and

providing an anti-stiction coating, wherein said anti-stiction coating is located between at least a portion of said reflective element and said transmissive element.

30. The method of claim 29, further comprising:

providing a transparent substrate;

providing a seal;

providing a backplate; and

adhering said substrate and said backplate with said seal, wherein said reflective element, said transmissive element, and said anti-stiction coating are located between said substrate and said backplate.

31. The method of claim 30, further comprising providing a desiccant, wherein said desiccant is located between said substrate and said backplate.

32. The method of claim 29, further comprising:

providing a sacrificial layer located between said reflective element and said transmissive element; and

removing at least a portion of the sacrificial material prior to providing an anti-stiction coating.

33. The method of claim 29, further comprising:

providing a sacrificial layer located between said reflective element and said transmissive element, wherein said anti-stiction coating is provided on at least a portion of said sacrificial layer.

34. The method of claim 29, wherein said anti-stiction coating comprises a self-aligning monolayer.

35. The method of claim 29, wherein said anti-stiction coating is selected from the group consisting of:

teflon, perfluorodecanoic carboxylic acid, octadecyltrichlorosilane (OTS), dichlorodimethylsilane, fluoro silane, chloro-fluoro silane, methoxy silane, trichlorosilane, silicone, polystyrene, polyurethane, a block copolymer containing a hydrophobic component, polysilazane, graphite, diamond-like carbide (DLC), silicon carbide (SiC), hydrogenated diamond coating, and fluorinated DLC.