MEMS devices with stiction bumps

• US 7,554,711 B2
• Filed: 07/24/2006
• Issued: 06/30/2009
• Est. Priority Date: 04/08/1998
• Status: Expired due to Term

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: IDC, LLC
• Inventors: Miles, Mark W.
• Primary Examiner(s): Lester; Evelyn A.
• Application Number:
  US11/492,535
• Publication Number:
  US 20060262380A1
• Time in Patent Office: 1,072 Days
• Field of Search: 359223-224, 359290-295, 359/298, 359846-849, 345/48, 345/84, 345/85, 345/108, 348/750, 348/755, 348/770, 348/771
• US Class Current: 359/224.1
• CPC Class Codes: G02B 19/0019 having reflective surfaces only (e.g. louvre systems, systems with multiple planar reflectors)
• CPC Class Codes: G02B 26/00 Optical devices or arrangements for the control of light using movable or deformable optical elements control of light by modification of the optical properties of the media of the elements involved therein G02F1/00
• 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
• CPC Class Codes: G02B 26/007 the movable or deformable optical element controlling the colour, i.e. a spectral characteristic, of the light
• CPC Class Codes: G02B 26/02 for controlling the intensity of light G02B26/004 takes precedence
• CPC Class Codes: G02B 26/06 for controlling the phase of light G02B26/08 takes precedence , measuring optical phase difference G01J9/00
• CPC Class Codes: G02B 26/0816 by means of one or more reflecting elements
• CPC Class Codes: G02B 26/0825 the reflecting element being a flexible sheet or membrane, e.g. for varying the focus flexible mirrors for cosmetic use A45D42/24
• 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: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G02B 27/0068 having means for controlling the degree of correction, e.g. using phase modulators, movable elements controlling the phase of light using moving or deformable elements G02B26/06
• CPC Class Codes: G02B 5/201 in the form of arrays
• CPC Class Codes: G02F 1/0128 based on electro-mechanical, magneto-mechanical, elasto-optic effects
• CPC Class Codes: G02F 2203/12 spatial light modulator
• CPC Class Codes: G09G 2300/0426 Layout of electrodes and connections
• CPC Class Codes: G09G 2300/0469 Details of the physics of pixel operation
• CPC Class Codes: G09G 2300/08 Active matrix structure, i.e. with use of active elements, inclusive of non-linear two terminal elements, in the pixels together with light emitting or modulating elements
• CPC Class Codes: G09G 2300/0809 Several active elements per pixel in active matrix panels
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2300/088 using a non-linear two-terminal element
• CPC Class Codes: G09G 3/2014 : by modulation of the duration of a single pulse during which the logic level remains constant
• CPC Class Codes: G09G 3/22 : using controlled light sources
• CPC Class Codes: G09G 3/3433 : using light modulating elements actuated by an electric field and being other than liquid crystal devices and electrochromic devices using liquid crystal devices G09G3/36; using electrochromic devices G09G3/38
• CPC Class Codes: G09G 3/3466 : based on interferometric effect
• CPC Class Codes: Y10T 29/49002 : Electrical device making
• CPC Class Codes: Y10T 29/4913 : Assembling to base an electrical component, e.g., capacitor, etc.

Abstract

An interferometric modulator comprising a substrate, a movable membrane and one or more stiction bumps disposed between the substrate and the movable membrane. The stiction bumps are configured to mitigate stiction between the substrate and the movable membrane.

Claims

1. A microelectromechanical structure (“

MEMS”

) device comprising an interferometric modulator (“

IMOD”

), wherein said IMOD comprises;

a substrate;

a movable membrane comprising a reflective surface, wherein a gap exists between said substrate and said movable membrane; and

one or more stiction bumps disposed between said substrate and said movable membrane, wherein said one or more stiction bumps are configured to mitigate stiction between said substrate and said movable membrane, wherein said one or more stiction bumps are fabricated on said reflective surface of said movable membrane.

2. The MEMS device of claim 1, wherein said one or more stiction bumps are actuation rails.

3. The MEMS device of claim 1, wherein said one or more stiction bumps maintains a finite distance between said membrane and said substrate when said membrane is fully actuated.

4. The MEMS device of claim 1, wherein said one or more stiction bumps dampen movement of said membrane when said membrane is actuated.

5. The MEMS device of claim 1, wherein said one or more stiction bumps are connected to a source of electricity.

6. The MEMS device of claim 1, wherein said one or more stiction bumps are metallic.

7. The MEMS device of claim 1 further comprising one or more stiction bumps located on said substrate.

8. The MEMS device of claim 1 wherein said substrate is transparent.

9. The MEMS device of claim 1, wherein said one or more stiction bumps are rectangular.

10. A method of making a microelectromechanical structure (“

MEMS”

) device comprising an interferometric modulator (“

IMOD”

), comprising;

providing a substrate;

forming a movable membrane comprising a reflective surface on said substrate, wherein a gap exists between said substrate and said movable membrane; and

providing at least one stiction bump configured to mitigate stiction between said substrate and said movable membrane.

11. The method of claim 10, wherein said at least one stiction bump is fabricated on said movable membrane.

12. The method of claim 10, wherein said substrate is transparent.

13. The method of claim 10, wherein said at least one stiction bump comprises at least one bottom electrode.

14. The method of claim 13, wherein said at least one stiction bump is an actuation rail.

15. The method of claim 10, wherein said at least one stiction bump maintains a finite distance between said membrane and said substrate when said membrane is filly actuated.

16. The method of claim 10, wherein said at least one stiction bump is connected to a source of electricity.

17. The method of claim 10, wherein providing at least one stiction bump comprises providing a metallic stiction bump.

18. The method of claim 10, wherein said at least one stiction bump comprises at least one surface electrode.

19. The method of claim 10, wherein said at least one stiction bump is located on said substrate.

20. A microelectromechanical structure (“

MEMS”

) device comprising an interferometric modulator (“

IMOD”

), the IMOD comprising;

a substrate;

a movable membrane comprising a reflective surface, wherein a gap exists between said substrate and said movable membrane; and

means for reducing stiction between said substrate and said movable membrane, wherein said means for reducing stiction is disposed on said reflective surface of said movable membrane.

21. The MEMS device of claim 20, wherein said means for reducing stiction comprises a rectangular rail.

22. The MEMS device of claim 20, wherein said means for reducing stiction comprises a stiction bump.

23. The MEMS device of claim 20, wherein said means for reducing stiction comprises an electrode.

24. The MEMS device of claim 21, wherein said rectangular rail is fabricated on said movable membrane.

25. The MEMS device of claim 23, wherein said electrode is fabricated on said movable membrane.

26. The MEMS device of claim 20, wherein said movable membrane comprises a movable plate.

27. The MEMS device of claim 26, wherein said means for reducing stiction between said substrate and said movable plate comprises a bump positioned on a lower surface of said movable plate and film disposed on said movable plate.