MEMS device and method of forming MEMS device

• US 20050073735A1
• Filed: 10/02/2003
• Published: 04/07/2005
• Est. Priority Date: 10/02/2003
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Nikkel, Eric L., Monroe, Michael G., Potochnik, Stephen J., Szepesi, Michele K., Tomasco, Richard P.
• Granted Patent: US 6,914,709 B2
• Time in Patent Office: Days
• US Class Current: 359/290
• CPC Class Codes: B81B 2201/042 Micromirrors, not used as optical switches
• CPC Class Codes: B81C 1/00174 See-saws
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means

Abstract

A method of forming a MEMS device includes providing a substructure including a base material and at least one conductive layer formed on a side of the base material, forming a dielectric layer over the at least one conductive layer of the substructure, defining an actuating area for the MEMS device on the dielectric layer, including depositing a conductive material on the dielectric layer and communicating the conductive material with the at least one conductive layer of the substructure through the dielectric layer, forming a sacrificial layer over the conductive material and the dielectric layer, including depositing silicon over the conductive material and the dielectric layer, and forming a substantially planar surface of the silicon, forming an actuating element over the sacrificial layer within the actuating area, including communicating the actuating element with the conductive material of the actuating area through the sacrificial layer, and substantially removing the sacrificial layer between the actuating element and the dielectric layer.

Claims

1. A method of forming a MEMS device, the method comprising:

providing a substructure including a base material and at least one conductive layer formed on a side of the base material;

forming a dielectric layer over the at least one conductive layer of the substructure;

defining an actuating area for the MEMS device on the dielectric layer, including depositing a conductive material on the dielectric layer and communicating the conductive material with the at least one conductive layer of the substructure through the dielectric layer;

forming a sacrificial layer over the conductive material and the dielectric layer, including depositing silicon over the conductive material and the dielectric layer, and forming a substantially planar surface of the silicon;

forming an actuating element over the sacrificial layer within the actuating area, including communicating the actuating element with the conductive material of the actuating area through the sacrificial layer; and

substantially removing the sacrificial layer between the actuating element and the dielectric layer.

2. The method of claim 1, wherein depositing the conductive material includes forming at least one electrode on the dielectric layer,

wherein the actuating element is adapted to move in response to application of an electric signal to the at least one electrode.

3. The method of claim 1, wherein forming the actuating element includes depositing a first material on the sacrificial layer, depositing and patterning a protective material on the first material, and depositing a second material on the protective material and the first material, and includes removing a portion of the second material and the protective material to expose a portion of the first material.

4. The method of claim 3, wherein the conductive material and at least the first material each include one of aluminum and an aluminum silicon alloy.

5. The method of claim 1, wherein substantially removing the sacrificial layer includes etching the sacrificial layer.

6. The method of claim 5, wherein etching the sacrificial layer includes dry etching the sacrificial layer.

7. The method of claim 1, further comprising:

forming a first barrier layer over the conductive material of the actuating area and the dielectric layer,

wherein forming the sacrificial layer includes forming the sacrificial layer over the first barrier layer.

8. The method of claim 7, wherein the first barrier layer includes one of titanium nitride, silicon nitride, and silicon oxide.

9. The method of claim 7, further comprising:

forming a second barrier layer over the sacrificial layer,

wherein forming the actuating element includes forming the actuating element over the second barrier layer.

10. The method of claim 9, wherein the second barrier layer includes one of titanium nitride, silicon nitride, and silicon oxide.

11. The method of claim 1, further comprising:

defining an electrical contact area for the MEMS device, including forming an opening through the dielectric layer to the at least one conductive layer of the substructure.

12. The method of claim 1, wherein the substructure includes a complementary metal oxide semi-conductor structure.

13. The method of claim 1, wherein the base material of the substructure includes silicon and the at least one conductive layer of the substructure includes aluminum.

14. The method of claim 1, wherein the dielectric layer includes silicon oxide.

15. A method of forming a micro-mirror device, the method comprising:

providing a substructure including a base material and at least one conductive layer formed on a side of the base material;

forming a layer of dielectric material over the at least one conductive layer of the substructure;

depositing a conductive material on the layer of dielectric material, including communicating the conductive material with the at least one conductive layer of the substructure through the layer of dielectric material;

forming a sacrificial layer of silicon over the conductive material and the layer of dielectric material;

forming a reflective element over the sacrificial layer of silicon; and

substantially removing the sacrificial layer of silicon between the reflective element and the layer of dielectric material.

16. The method of claim 15, wherein depositing the conductive material includes forming at least one electrode on the layer of dielectric material,

wherein the reflective element is adapted to move in response to application of an electrical signal to the at least one electrode.

17. The method of claim 15, wherein forming the reflective element includes depositing a hinge material over the sacrificial layer of silicon, depositing and patterning a protective material over the hinge material, and depositing a reflective material over the protective material and the hinge material, and includes removing a portion of the reflective material and the protective material to expose a portion of the hinge material.

18. The method of claim 17, wherein the conductive material and at least the hinge material each include one of aluminum and an aluminum silicon alloy.

19. The method of claim 15, wherein substantially removing the sacrificial layer includes dry etching the sacrificial layer.

20. The method of claim 15, further comprising:

forming a first layer of barrier material over the conductive material and the layer of dielectric material,

wherein forming the sacrificial layer includes forming the sacrificial layer over the first layer of barrier material, and wherein substantially removing the sacrificial layer includes substantially removing the sacrificial layer and the first layer of barrier material between the reflective element and the layer of dielectric material.

21. The method of claim 20, wherein the barrier material includes one of titanium nitride, silicon nitride, and silicon oxide.

22. The method of claim 20, further comprising:

forming a second layer of barrier material over the sacrificial layer of silicon,

wherein forming the reflective element includes forming the reflective element over the second layer of barrier material, and

wherein substantially removing the sacrificial layer includes substantially removing the second layer of barrier material, the sacrificial layer, and the first layer of barrier material between the reflective element and the layer of dielectric material.

23. The method of claim 22, wherein the barrier material includes one of titanium nitride, silicon nitride, and silicon oxide.

24. The method of claim 15, further comprising:

defining an electrical contact area for the micro-mirror device, including forming an opening through the dielectric layer to the at least one conductive layer of the substructure.

25. The method of claim 15, wherein the substructure includes a complementary metal oxide semi-conductor structure.

26. The method of claim 15, wherein the base material of the substructure includes silicon and the at least one conductive layer of the substructure includes aluminum.

27. The method of claim 15, wherein the dielectric material includes silicon oxide.

28. A micro-mirror device, comprising:

a substructure including a base material and at least one conductive layer formed on a side of the base material;

a dielectric layer formed over the at least one conductive layer of the substructure;

at least one electrode formed on the dielectric layer; and

a reflective element extended over the dielectric layer and the at least one electrode, the reflective element including a hinge material and a reflective material formed on the hinge material,

wherein the reflective element is adapted to move in response to application of an electrical signal to the at least one electrode.

29. The device of claim 28, wherein the hinge material of the reflective element is adapted to flex to move the reflective element.

30. The device of claim 28, further comprising:

an electrical contact area including an opening formed through the dielectric layer to the at least one conductive layer of the substructure.

31. The device of claim 28, further comprising:

a sacrificial layer of silicon formed over the dielectric layer and the at least one electrode,

wherein the reflective element is formed over the sacrificial layer, and wherein the sacrificial layer is adapted to be removed by an etch process after the reflective element is formed.

32. The device of claim 31, wherein the etch process includes a dry etch process.

33. The device of claim 31, further comprising:

a first barrier layer formed over the dielectric layer and the at least one electrode,

wherein the sacrificial layer is formed over the first barrier layer, and wherein the sacrificial layer and the first barrier layer are adapted to be removed by the etch process after the reflective element is formed.

34. The device of claim 33, wherein the first barrier layer includes one of titanium nitride, silicon nitride, and silicon oxide.

35. The device of claim 33, further comprising:

a second barrier layer formed over the sacrificial layer of silicon,

wherein the reflective element is formed over the second barrier layer, and wherein the second barrier layer, the sacrificial layer, and the first barrier layer are adapted to be removed by the etch process after the reflective element is formed.

36. The device of claim 35, wherein the first barrier layer and the second barrier layer each include one of titanium nitride, silicon nitride, and silicon oxide.

37. The device of claim 28, wherein the substructure includes a complementary metal oxide semi-conductor structure.

38. The device of claim 28, wherein the base material of the substructure includes silicon and the at least one conductive layer of the substructure includes aluminum.

39. The device of claim 28, wherein the dielectric layer includes silicon oxide.

40. A display device including the micro-mirror device of claim 28.

41. A micro-mirror device, comprising:

a substructure including a base material and at least one conductive layer formed on a side of the base material;

a dielectric layer formed over the at least one conductive layer of the substructure;

at least one electrode formed on the dielectric layer; and

a reflective element extended over the dielectric layer and the at least one electrode, including means formed in the reflective element for facilitating movement of the reflective element in response to application of an electrical signal to the at least one electrode.

42. The device of claim 41, wherein means formed in the reflective element for facilitating movement of the reflective element includes a hinge material and a reflective material formed on the hinge material, wherein the hinge material is adapted to flex to facilitate movement of the reflective element.

43. The device of claim 41, further comprising:

means for forming the reflective element over the dielectric layer and the at least one electrode, including a sacrificial layer of silicon formed over the dielectric layer and the at least one electrode,

wherein the reflective element is formed over the sacrificial layer, and the sacrificial layer is removed after the reflective element is formed.

44. The device of claim 43, further comprising:

means for protecting the dielectric layer and the at least one electrode from the sacrificial layer of silicon; and

means for protecting the reflective element from the sacrificial layer of silicon.

45. The device of claim 44, wherein means for protecting the dielectric layer and the at least one electrode includes a first barrier layer formed over the dielectric layer and the at least one electrode, and wherein means for protecting the reflective element includes a second barrier layer formed over the sacrificial layer of silicon,

wherein the sacrificial layer is formed over the first barrier layer, and the reflective element is formed over the second barrier layer, and wherein the second barrier layer, the sacrificial layer of silicon, and the first barrier layer are removed after the reflective element is formed.