Method for containing a device and a corresponding device

• US RE44,246 E1
• Filed: 07/27/2011
• Issued: 05/28/2013
• Est. Priority Date: 12/24/2003
• Status: Active Grant

• Current Assignee: Qorvo US, Inc. (Qorvo, Inc.)
• Original Assignee: Cavendish Kinetics Ltd. (Qorvo, Inc.)
• Inventors: Heuvelman, Willem Matthijs
• Primary Examiner(s): MULPURI, SAVITRI
• Application Number:
  US13/191,865
• Time in Patent Office: 671 Days
• Field of Search: 438/50, 438/51, 438/106, 438/107, 438/113, 438/48, 438/52, 438/53, 438/127
• US Class Current: 438/52
• CPC Class Codes: B81B 2207/015 the micromechanical device and the control or processing electronics being integrated on the same substrate
• CPC Class Codes: B81B 2207/096 through the substrate
• CPC Class Codes: B81C 1/00301 Connecting electric signal lines from the MEMS device with external electrical signal lines, e.g. through vias
• CPC Class Codes: B81C 2203/0145 Hermetically sealing an opening in the lid
• CPC Class Codes: H01L 23/5256 comprising fuses, i.e. connections having their state changed from conductive to non-conductive
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

A method of enclosing a micromechanical element formed between a base layer and one or more metallization layers includes forming one or more encapsulating layers over the micromechanical element and providing an encapsulating wall surrounding the element extending between the base layer and the one or more encapsulating layers. An electrical connection is provided between the base layers and the one or more metallization layers formed above the micromechanical element.

Claims

1. A method of enclosing a micromechanical element formed between a base layer and one or more metallization layers comprising:

forming a first encapsulating layer over at least part of the micromechanical element;

depositing a second encapsulating layer over the first encapsulating layer and providing an encapsulating wall surrounding the micromechanical element to form a lateral sealing wall extending between the base layer and the one or more encapsulating layers;

depositing the one or more metallization layers over the first encapsulating layer;

providing electrical connection between the base layer and the one or more metallization layers formed above the micromechanical element;

etching through the first encapsulating layer and a sacrificial layer disposed therebelow to form an opening through the first encapsulating layer and the sacrificial layer;

introducing an etching agent through the opening; and

removing the sacrificial layer, wherein the micromechanical element is disposed in a cavity that is at least partially bordered by the encapsulating wall.

2. The method according to claim 1, wherein the encapsulating wall comprises a via filled with tungsten.

3. The method according to claim 1, wherein the encapsulating wall comprises a via that is lined with TiN and filled with tungsten.

4. The method according to claim 3, wherein the encapsulating wall provides an electrical connection between the base layer and the one or more metallization layers.

5. The method according to claim 1, wherein the encapsulating wall extends through the base layer and the first and second encapsulating layers.

6. The method according to claim 1, wherein the encapsulating wall is formed from one or more stacked plugs.

7. The method according to claim 6, wherein the one or more stacked plugs provide electrical connection between the base layer and the one or more metallization layers.

8. The method according to claim 7, wherein the one or more stacked plugs comprises a TiN liner and tungsten fill.

9. A method of forming and enclosing a micromechanical element between a base layer and one or more metallization layers, comprising:

applying a first sacrificial layer of an etchable material over at least a portion of the base layer;

patterning the first sacrificial layer to define at least a portion of the shape of the micromechanical element;

applying at least one layer of a micromechanical element material over at least a portion of the first sacrificial layer;

patterning the micromechanical element material to form at least a portion of the micromechanical element;

applying a second sacrificial layer of an etchable material over the micromechanical element;

applying a first encapsulating layer over at least a portion of the second sacrificial layer;

depositing a second encapsulating layer over the first encapsulating layer and providing an encapsulating wall surrounding the micromechanical element to form a lateral sealing wall extending between the base layer and the one or more encapsulating layers;

depositing the one or more metallization layers over the first encapsulating layer;

providing electrical connection between the base layer and the one or more metallization layers;

etching through the first encapsulating layer and the second sacrificial layer to form an opening through the first encapsulating layers and the second sacrificial layer;

introducing an etching agent through the opening; and

removing at least part of the first and second sacrificial layers to at least partly free the micromechanical element, wherein the micromechanical element is disposed in a cavity that is at least partially bordered by the encapsulating wall.

10. The method according to claim 9, wherein the first and second sacrificial layers comprise an etchable silicon-based material.

11. The method according to claim 9, wherein the first and second sacrificial layers comprise an etchable polymer-based material.

12. The method according to claim 9, wherein the first or second sacrificial layers comprise an etchable silicon-based material.

13. The method according to claim 9, wherein the first or second sacrificial layers comprise an etchable polymer-based material.

14. The method according to claim 9, further comprising planarizing the first encapsulating layer.

15. The method according to claim 14, wherein the planarizing comprises chemical-mechanical polishing.

16. The method according to claim 9, wherein the encapsulating wall comprises a via filled with tungsten.

17. The method according to claim 9, wherein the encapsulating wall comprises a via that is lined with TiN and filled with tungsten.

18. The method according to claim 9, wherein the encapsulating wall extends through the base layer and the one or more encapsulating layers.

19. The method according to claim 9, wherein the encapsulating wall provides an electrical connection between the base layer and the one or more metallization layers.

20. The method according to claim 9, wherein the encapsulating wall is formed from one or more stacked plugs.

21. The method according to claim 20, wherein the one or more stacked plugs provide electrical connection between the base layer and the one or more metallization layers.

22. The method according to claim 21, wherein the one or more stacked plugs comprises a TiN liner and tungsten fill.

23. A method of enclosing a micromechanical element, comprising:

forming a first encapsulating layer over at least part of the micromechanical element;

depositing a second encapsulating layer over the first encapsulating layer and providing an encapsulating wall surrounding the micromechanical element to form a lateral sealing wall extending between the base layer and the one or more encapsulating layers;

depositing one or more metallization layers over the first encapsulating layer to provide an electrical connection between the base layer and the one or more metallization layers formed above the micromechanical element; and

freeing the micromechanical element disposed between the one or more metallization layers and the base layer, the freeing comprising;

etching through the first encapsulating layer and a sacrificial layer disposed therebelow to form an opening through the first encapsulating layer and the sacrificial layer;

introducing an etching agent through the opening; and

removing the sacrificial layer, wherein the micromechanical element is disposed in a cavity that is at least partially bordered by the encapsulating wall.

24. The method according to claim 23, wherein the encapsulating wall comprises tungsten.

25. The method according to claim 23, wherein the encapsulating wall comprises titanium nitride.

26. The method according to claim 25, wherein providing the encapsulating wall comprises forming the encapsulating wall between the base layer and the one or more metallization layers to provide an electrical connection therebetween.

27. The method according to claim 23, wherein providing the encapsulating wall comprises forming the encapsulating wall to extend through the base layer and the first and second encapsulating layers.

28. The method according to claim 23, wherein providing the encapsulating wall comprises forming one or more stacked plugs.

29. The method according to claim 28, wherein forming the one or more stacked plugs comprises forming the one or more stacked plugs to provide an electrical connection between the base layer and the one or more metallization layers.

30. The method according to claim 29, wherein forming the one or more stacked plugs comprises forming a titanium nitride liner and a tungsten fill.