Method and device for packaging a substrate

• US 8,045,835 B2
• Filed: 08/15/2008
• Issued: 10/25/2011
• Est. Priority Date: 09/27/2004
• Status: Expired due to Fees

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Miles, Mark, Palmateer, Lauren, Chui, Clarence, Sampsell, Jeffrey B., Cummings, William J., Kothari, Manish, Gally, Brian
• Primary Examiner(s): KIM, ELLEN E
• Application Number:
  US12/192,908
• Publication Number:
  US 20090059342A1
• Time in Patent Office: 1,166 Days
• Field of Search: 385/147, 359/247, 359/291
• US Class Current: 385/147
• CPC Class Codes: B81B 2201/047 Optical MEMS not provided for in B81B2201/042 - B81B2201/045
• CPC Class Codes: B81C 1/00285 using materials for controlling the level of pressure, contaminants or moisture inside of the package, e.g. getters
• CPC Class Codes: B81C 1/00333 Aspects relating to packaging of MEMS devices, not covered by groups B81C1/00269 - B81C1/00325
• CPC Class Codes: B81C 2203/0136 Growing or depositing of a covering layer
• CPC Class Codes: B81C 2203/0145 Hermetically sealing an opening in the lid
• 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 26/0825 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

Abstract

A package structure and method of packaging for an interferometric modulator. A thin film material is deposited over an interferometric modulator and transparent substrate to encapsulate the interferometric modulator. A gap or cavity between the interferometric modulator and the thin film provides a space in which mechanical parts of the interferometric modulator may move. The gap is created by removal of a sacrificial layer that is deposited over the interferometric modulator.

Claims

1. A method of manufacturing a display, the method comprising:

providing an electro-mechanical device, wherein said electro-mechanical device comprises a first sacrificial layer;

depositing a second sacrificial layer over said electro-mechanical device, wherein said second sacrificial layer is exposed to a portion of said first sacrificial layer;

depositing a thin film backplane over and in contact with said second sacrificial layer, wherein the thin film backplane has an opening; and

after depositing the thin film backplane, removing said first and said second sacrificial layers,

wherein at least a part of said first sacrificial layer is removed concurrently with at least a part of said second sacrificial layer,

wherein removing said second sacrificial layer provides a gap above said electro-mechanical device and below said thin film backplane.

2. The method of claim 1, wherein said electro-mechanical device comprises an interferometric modulator.

3. The method of claim 2, wherein said first sacrificial layer is disposed in an optical cavity of said interferometric modulator.

4. The method of claim 1, wherein said electro-mechanical device comprises an array of moveable mirrors configured to interferometrically modulate light.

5. The method of claim 1, wherein all of said first and all of said second sacrificial layers are removed at the same time.

6. The method of claim 1, wherein said thin film backplane comprises a hermetic material.

7. The method of claim 1, wherein said first sacrificial layer or said second sacrificial layer is formed of molybdenum, silicon, tungsten, or titanium.

8. The method of claim 1, wherein said first sacrificial layer or said second sacrificial layer is removed with xenon diflouride.

9. The method of claim 1 further comprising depositing an overcoat layer over said thin film backplane.

10. The method of claim 1, wherein said electro-mechanical device comprises a microelectromechanical systems device.

18. The method of claim 1, wherein said second sacrificial layer is deposited to a thickness in the range of about 1000 Å

to about 5000 Å

.

19. The method of claim 1, wherein said thin film is about 1 μ

m thick.

20. The method of claim 2, wherein said interferometric modulator comprises a layer of indium tin oxide of about 500 Å

thick.

11. A method of manufacturing a display comprising a plurality of electro-mechanical devices, the method comprising:

providing an electro-mechanical device, wherein said electro-mechanical device comprises;

a first sacrificial layer; and

a first opening into said electro-mechanical device exposing said sacrificial layer;

providing a thin film backplane over said electro-mechanical device, wherein the thin film backplane comprises a second opening;

providing a second sacrificial layer between said thin film backplane and said electro-mechanical device;

introducing a release material through said first and second openings to release the first sacrificial layer and second sacrificial layer, and

wherein at least a part of said first sacrificial layer is removed concurrently with at least a part of said second sacrificial layer.

12. The method of claim 11, wherein all of said first sacrificial layer and all of said second sacrificial layer are removed at the same time.

13. The method of claim 11, wherein said release material is xenon diflouride.

14. The method of claim 11, wherein said electro-mechanical device comprises an interferometric modulator.

15. The method of claim 11, wherein said electro-mechanical device comprises an array of moveable mirrors configured to interferometrically modulate light.

16. The method of claim 11, wherein said electro-mechanical device comprises a microelectromechanical systems device.

17. A display device, comprising:

a transparent substrate;

an interferometric modulator disposed on the transparent substrate, said interferometric modulator comprising;

a first sacrificial layer; and

a first opening exposing said first sacrificial layer; and

a thin film backplane sealing said interferometric modulator within a package between said transparent substrate and said thin film backplane,

wherein a second sacrificial layer is positioned between said thin film backplane and said interferometric modulator and contacts said first sacrificial layer exposed at said first opening, and

wherein a second opening exists in said thin film backplane.