Method and device for packaging a substrate

• US 8,682,130 B2
• Filed: 09/13/2011
• Issued: 03/25/2014
• Est. Priority Date: 09/27/2004
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Palmateer, Lauren, Cummings, William J., Gally, Brian, Miles, Mark, Sampsell, Jeffrey B., Chui, Clarence, Kothari, Manish
• Primary Examiner(s): KIM, ELLEN E
• Application Number:
  US13/231,640
• Publication Number:
  US 20120002266A1
• Time in Patent Office: 924 Days
• Field of Search: 385/147, 359/247, 359/820, 359/290, 438/106, 438/51
• 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 display device, comprising:

an electromechanical device disposed on a substrate and having a first opening, the electromechanical device including a first sacrificial layer and a movable layer disposed over at least a portion of the sacrificial layer;

a second sacrificial layer positioned over the electromechanical device and exposed to the first sacrificial layer through the first opening, wherein the first sacrificial layer and the second sacrificial layer are formed of different materials; and

a thin film backplane having a second opening, the thin film backplane positioned over the second sacrificial layer and sealing the electromechanical device within a package formed between the substrate and the thin film backplane.

2. The display device of claim 1, wherein at least one of the first sacrificial layer and the second sacrificial layer is configured to be removed with xenon diflouride.

3. The display device of claim 1, wherein the first sacrificial layer is formed of at least one of molybdenum, silicon, tungsten, and titanium.

4. The display device of claim 1, wherein the second sacrificial layer is formed of at least one of molybdenum, silicon, tungsten, and titanium.

5. The display device of claim 1, wherein the thin film backplane is formed of a hermetic material.

6. The display device of claim 1 further comprising a desiccant disposed in the package between the thin film backplane and the electromechanical device.

7. The display device of claim 1 further comprising an overcoat layer deposited over at least a portion of the thin film backplane.

8. The display device of claim 7, wherein the overcoat layer is deposited over the entirety of the thin film backplane.

9. The display device of claim 7, wherein the overcoat layer is formed of at least one of a hermetic material, a vapor barrier material, and a polymer.

10. The display device of claim 1, wherein the substrate includes a transparent substrate.

11. The display device of claim 1, wherein the thin film backplane is formed of at least one of a metal and a polymer.

12. A method of manufacturing a display device, comprising:

providing an electromechanical device on a substrate, the electromechanical device having a first opening and including a first sacrificial layer and a movable layer disposed over at least a portion of the sacrificial layer;

depositing a second sacrificial layer over the electromechanical device such that the second sacrificial layer is exposed to the first sacrificial layer through the first opening, the first sacrificial layer and the second sacrificial layer formed of different materials; and

depositing a thin film backplane over the second sacrificial layer to seal the electromechanical device within a package formed between the substrate and the thin film backplane, the thin film backplane having a second opening.

13. The method of claim 12 further comprising depositing an overcoat layer over at least a portion of the thin film backplane.

14. The method of claim 12 further comprising removing at least one of the first and the second sacrificial layers with xenon diflouride.

15. A display device, comprising:

an electromechanical device disposed on a substrate, the electromechanical device having a first opening and including a movable layer disposed over at least a portion of a first sacrificial layer;

a second sacrificial layer positioned over the electromechanical device, the second sacrificial layer exposed to a portion of the first sacrificial layer through the first opening;

a thin film backplane disposed over the second sacrificial layer such that a package structure is formed between the thin film backplane and the substrate; and

a desiccant disposed within the package structure.

16. The display device of claim 15, wherein the desiccant is disposed between the thin film backplane and the electromechanical device.

17. The display device of claim 15, wherein the thin film backplane is formed of a metal or a polymer.

18. The display device of claim 15 further comprising an overcoat layer deposited over at least a portion of the thin film backplane.

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

providing an electromechanical device on a substrate, the electromechanical device having a first opening and including a movable layer disposed over a first sacrificial layer;

depositing a second sacrificial layer over the electromechanical device and the desiccant, the second sacrificial layer exposed to a portion of the first sacrificial layer through the first opening;

depositing a thin film backplane over the second sacrificial layer such that a package structure is formed between the thin film backplane and the substrate, wherein a desiccant is contained within the package structure; and

removing the first and the second sacrificial layers, wherein removing the second sacrificial layer provides a gap above the electromechanical device and below the thin film backplane, and wherein at least part of the desiccant is not removed with the first sacrificial layer and the second sacrificial layer.

20. The method of claim 19, wherein at least a part of the first sacrificial layer is removed concurrently with at least a part of the second sacrificial layer.

21. The method of claim 19, wherein substantially all of the first and the second sacrificial layers are removed at the same time.

22. The method of claim 19, wherein at least one of the first sacrificial layer and the second sacrificial layer is removed with xenon difluoride.

23. The method of claim 19, wherein the first sacrificial layer and the second sacrificial layer are formed of different materials.

24. The method of claim 19, wherein the first sacrificial layer or the second sacrificial layer is formed of at least one of molybdenum, silicon, tungsten, or titanium.

25. The method of claim 19 further comprising depositing an overcoat layer over the thin film backplane, wherein the overcoat layer is formed of polymer.

26. The method of claim 19, wherein the thin film backplane is formed of a hermetic material.

27. The method of claim 19, wherein the thin film backplane is formed of a metal.