Encapsulation methods for interferometric modulator and MEMS devices

• US 7,782,522 B2
• Filed: 07/17/2008
• Issued: 08/24/2010
• Est. Priority Date: 07/17/2008
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Lan, Je-Hsiung
• Primary Examiner(s): Spector; David N
• Application Number:
  US12/175,355
• Publication Number:
  US 20100014146A1
• Time in Patent Office: 768 Days
• Field of Search: 257/433, 257/444, 257/787, 257/788, 257/E21.499, 257/E21.502, 257/E21.503, 359/290
• US Class Current: 359/290
• CPC Class Codes: B81B 2201/047 Optical MEMS not provided for in B81B2201/042 - B81B2201/045
• CPC Class Codes: B81B 2207/095 through the lid
• CPC Class Codes: B81C 1/0023 Packaging together an electronic processing unit die and a micromechanical structure die MEMS packages B81B7/0032; MEMS packaging processes B81C1/00261
• 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

Abstract

Methods and devices used for the encapsulation of MEMS devices, such as an interferometric modulator, are disclosed. Encapsulation is provided to MEMS devices to protect the devices from such environmental hazards as moisture and mechanical shock. In addition to the encapsulation layer providing protection from environmental hazards, the encapsulation layer is additionally planarized so as to function as a substrate for additional circuit elements formed above the encapsulation layer.

Claims

1. A microelectromechanical system (MEMS) device, comprising:

a substrate;

a MEMS element on the substrate, the MEMS element comprising a movable component;

an encapsulation layer encapsulating the MEMS element, wherein the encapsulation layer is planarized; and

an electronic element on or over the encapsulation layer.

2. The device of claim 1, wherein the encapsulation layer is planarized with a chemical mechanical planarization method.

3. The device of claim 1, wherein the encapsulation layer is planarized with a mechanical polishing method.

4. The device of claim 1, wherein the MEMS element comprises an interferometric modulator.

5. The device of claim 1, wherein the MEMS element comprises a moveable component configured to move between first and second positions, the first position being nearer the encapsulation layer than the second position.

6. The device of claim 1, wherein the encapsulation layer is spaced apart from the MEMS element.

7. The device of claim 1, wherein the encapsulation layer comprises a hole.

8. The device of claim 7, wherein the hole is plugged.

9. The device of claim 7, wherein the hole is plugged with a dielectric material.

10. The device of claim 7, wherein the hole is plugged with a conductive material.

11. The device of claim 10, wherein the conductive material is electrically connected to the MEMS element.

12. The device of claim 1, wherein the electronic element comprises an interconnect layer.

13. The device of claim 1, wherein the electronic element comprises a connector.

14. The device of claim 1, wherein the electronic element comprises an active device.

15. The device of claim 1, wherein the electronic element comprises a passive device.

16. The device of claim 1, wherein the electronic element comprises a thin film transistor.

27. The device of claim 1, wherein the encapsulating means is planarized with a chemical mechanical planarization method.

17. A method of manufacturing a microelectromechanical system (MEMS) device, the method comprising:

forming a MEMS element on a substrate, the MEMS element comprising a gap;

forming an encapsulation layer encapsulating the MEMS element;

planarizing said encapsulation layer; and

forming an electronic element on the encapsulation layer.

18. The method of claim 17, wherein forming the encapsulation layer comprises forming a hole.

19. The method of claim 18, wherein forming the MEMS element comprises depositing a sacrificial layer, and the method further comprises removing the sacrificial layer through the hole.

20. The method of claim 19, wherein the electronic element is formed prior to removing the sacrificial layer.

21. The method of claim 19, further comprising:

modifying the environment of the MEMS element; and

plugging the hole.

22. The method of claim 18, further comprising plugging the hole.

23. The method of claim 22, further comprising plugging the hole, wherein the encapsulation layer is planarized after the hole is plugged.

24. The method of claim 17, further comprising electrically connecting the MEMS element with the electronic element through the encapsulation layer.

25. A microelectromechanical system (MEMS) device, comprising:

means for supporting a MEMS element, the MEMS element comprising a movable component;

means for encapsulating the MEMS element, wherein the encapsulating means is planarized; and

means for processing electronic signals on or over the encapsulating means.

26. The device of claim 25, wherein the supporting means comprises a substrate, the encapsulating means comprises an encapsulation layer, and the processing means comprises an electronic element.

28. The device of claim 25, wherein the encapsulating means is planarized with a mechanical polishing method.

29. The device of claim 25, wherein the MEMS element comprises an interferometric modulator.

30. The device of claim 25, wherein the encapsulating means comprises a hole.

31. The device of claim 30, wherein the hole is plugged.

32. The device of claim 31, wherein the processing means is electrically connected to the MEMS element through the hole.

33. The device of claim 25, wherein the electronic element comprises a connector.

34. The device of claim 25, wherein the processing means comprises a thin film transistor.