MEMS device and method of forming MEMS device

• US 6,917,459 B2
• Filed: 06/03/2003
• Issued: 07/12/2005
• Est. Priority Date: 06/03/2003
• Status: Expired due to Term

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Potochnik, Stephen J, Nikkel, Eric L., Monroe, Michael G., Bengali, Sadiq, Szepesi, Mickey
• Primary Examiner(s): Epps, Georgia
• Assistant Examiner(s): Dinh, Jack
• Application Number:
  US10/454,423
• Publication Number:
  US 20040245588A1
• Time in Patent Office: 770 Days
• Field of Search: 359290-292, 359/295, 359/298, 359/214, 359/224, 359/230, 257/415, 257/678, 257/723, 216/2, 216/11, 216/13, 216/24, 216/88, 438/7, 438/17, 438/22, 438/24, 438/28, 438/48, 438/53, 438/599, 438/691, 438/734, 427/162, 427/534, 427/255.6
• US Class Current: 359/290
• CPC Class Codes: B81B 2201/042 Micromirrors, not used as optical switches
• CPC Class Codes: B81B 2203/0181 See-saws
• CPC Class Codes: B81C 1/00801 Avoid alteration of functional structures by etching, e.g. using a passivation layer or an etch stop layer B81C1/00595, B81C1/00468 take precedence
• CPC Class Codes: B81C 2203/0714 Forming the micromechanical structure with a CMOS process
• CPC Class Codes: B81C 2203/0771 Stacking the electronic processing unit and the micromechanical structure
• 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 first side of the base material, forming a dielectric layer over the at least one conductive layer of the substructure, forming a protective layer over the dielectric layer, defining an electrical contact area for the MEMS device on the protective layer, and forming an opening within the electrical contact area through the protective layer and the dielectric layer to the at least one conductive layer of the substructure.

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 first side of the base material;

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

forming a protective layer over the dielectric layer;

defining an electrical contact area for the MEMS device on the protective layer; and

forming an opening within the electrical contact area through the protective layer and the dielectric layer to the at least one conductive layer of the substructure.

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

3. 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.

4. The method of claim 1, wherein forming the dielectric layer includes depositing a first dielectric material over the at least one conductive layer of the substructure, and forming a substantially planar surface of the first dielectric material.

5. The method of claim 4, wherein the first dielectric material includes tetraethylorthosilicate.

6. The method of claim 4, wherein forming the protective layer includes depositing a second dielectric material over the substantially planar surface of the first dielectric material.

7. The method of claim 6, wherein the second dielectric material includes silicon carbide.

8. The method of claim 1, wherein defining the electrical contact area includes depositing an etch resistant material on the protective layer and defining a boundary of the electrical contact area with the etch resistant material, and

wherein forming the opening within the electrical contact area includes etching within the boundary of the electrical contact area through the protective layer and the dielectric layer to the at least one conductive layer of the substructure.

9. The method of claim 8, wherein the etch resistant material includes titanium nitride.

10. The method of claim 8, further comprising:

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

11. The method of claim 10, further comprising:

forming a sacrificial layer over the conductive material and the protective layer; and

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

12. The method of claim 11, wherein forming the sacrificial layer includes depositing a dielectric material over the conductive material and the protective layer, and forming a substantially planar surface of the dielectric material.

13. The method of claim 12, wherein the dielectric material includes tetraethylorthosilicate.

14. The method of claim 12, wherein forming the actuating element includes depositing a material over the substantially planar surface of the dielectric material.

15. The method of claim 11, further comprising:

forming at least one electrode on the protective layer within the actuating area,

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

16. The method of claim 11, further comprising:

forming a mask layer over the actuating element and the sacrificial layer, including defining a mask opening in the mask layer within the electrical contact area, and

wherein forming the opening within the electrical contact area includes forming the opening through the mask opening in the mask layer and the sacrificial layer to the boundary of the electrical contact area.

17. The method of claim 16, further comprising:

removing the mask layer;

temporarily filling the opening within the electrical contact area with a protective material; and

substantially removing the sacrificial layer between the actuating element and the protective layer, including etching the sacrificial layer.

18. 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 first side of the base material;

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

forming a layer of a material resistant to a second etch process within the layer of the dielectric material;

defining an electrical contact area for the micro-mirror device on the material resistant to the second etch process with a material resistant to a first etch process;

forming a reflective element over the dielectric material;

forming an opening in the electrical contact area through the dielectric material and the material resistant to the second etch process with the first etch process, including forming the opening to the at least one conductive layer of the substructure and defining an outline of the opening with the material resistant to the first etch process; and

substantially removing the dielectric material between the reflective element and the material resistant to the second etch process with the second etch process.

19. The method of claim 18, wherein forming the layer of the dielectric material and forming the layer of the material resistant to the second etch process includes forming a first portion of the layer of the dielectric material, forming the layer of the material resistant to the second etch process over the first portion, and forming a second portion of the layer of the dielectric material over the layer of the material resistant to the second etch process.

20. The method of claim 18, further comprising:

forming a conductive path on the material resistant to the second etch process, including communicating the conductive path with the reflective element and communicating the conductive path with the at least one conductive layer of the substructure through the material resistant to the second etch process and the dielectric material.

21. The method of claim 18, further comprising:

forming at least one electrode on the material resistant to the second etch process,

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

22. The method of claim 18, wherein forming the opening in the electrical contact area includes forming a mask layer over the reflective element and the dielectric material, and patterning the mask layer to define an exposed portion of the dielectric material in the electrical contact area, and includes etching the exposed portion of the dielectric material with the first etch process.

23. The method of claim 18, wherein substantially removing the dielectric material between the reflective element and the material resistant to the second etch process includes temporarily filling the opening in the electrical contact area with a protective material resistant to the second etch process.

24. The method of claim 18, wherein the substructure includes a complementary metal oxide semi-conductor structure.

25. The method of claim 18, wherein the base material of the substructure includes silicon and the at least one conductive layer of the substructure includes aluminum.

26. The method of claim 18, wherein the dielectric material includes tetraethylorthosilicate.

27. The method of claim 18, wherein the material resistant to the second etch process includes silicon carbide.

28. The method of claim 18, wherein the material resistant to the first etch process includes titanium nitride.

29. The method of claim 18, wherein the first etch process includes a dry etch process.

30. The method of claim 18, wherein the second etch process includes a wet etch process.

31. A MEMS device, comprising:

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

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

a protective layer formed over the dielectric layer;

an actuating element extended over the protective layer; and

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

32. The device of claim 31, further comprising:

a conductive path formed on the protective layer, the conductive path communicated with the actuating element and communicated with the at least one conductive layer of the substructure through the protective layer and the dielectric layer.

33. The device of claim 31, further comprising:

at least one electrode formed on the protective layer,

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

34. The device of claim 31, further comprising:

an etch resistant material provided on the protective layer in the electrical contact area, the etch resistant material defining a boundary of the opening of the electrical contact area and adapted to mask a portion of the protective layer when the opening is formed.

35. The device of claim 34, further comprising:

a sacrificial layer formed over the protective layer,

wherein the actuating element is formed over the sacrificial layer, and the sacrificial layer is adapted to be removed after the actuating element is formed.

36. The device of claim 35, further comprising:

a mask layer formed over the actuating element and the sacrificial layer, the mask layer including a mask opening exposing a portion of the sacrificial layer,

wherein the opening of the electrical contact area is adapted to be formed through the mask opening and the sacrificial layer to the etch resistant material provided on the protective layer, and

wherein the mask layer is adapted to be removed after the opening of the electrical contact area is formed.

37. The device of claim 36, wherein the opening of the electrical contact area is adapted to be formed with a first etch process, and the sacrificial layer is adapted to be removed with a second etch process.

38. The method of claim 37, wherein the first etch process is a dry etch and the second etch process is a wet etch.

39. The device of claim 35, wherein the sacrificial layer includes tetraethylorthosilicate.

40. The device of claim 31, wherein the protective layer includes silicon carbide.

41. The device of claim 31, wherein the dielectric layer includes tetraethylorthosilicate.

42. The device of claim 31, wherein the substructure includes a complementary metal oxide semi-conductor structure.

43. The device of claim 31, wherein the base material of the substructure includes silicon, and the at least one conductive layer of the substructure includes aluminum.

44. The device of claim 31, wherein the MEMS device includes a micro-mirror device, and the actuating element includes a reflective element.

45. A micro-mirror device, comprising:

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

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

a second dielectric layer formed over the first dielectric layer;

a reflective element extended over the second dielectric layer; and

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

46. The device of claim 45, further comprising:

a conductive path formed on the second dielectric layer, the conductive path communicated with the reflective element and communicated with the at least one conductive layer of the substructure through the second dielectric layer and the first dielectric layer.

47. The device of claim 45, further comprising:

at least one electrode formed on the second dielectric layer,

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

48. The device of claim 45, further comprising:

a material resistant to a first etch process provided on the second dielectric layer in the electrical contact area,

wherein the opening of the electrical contact area is adapted to be formed with the first etch process and the material resistant to the first etch process is adapted to mask a portion of the second dielectric layer.

49. The device of claim 48, further comprising:

a sacrificial layer formed over the second dielectric layer,

wherein the reflective element is formed over the sacrificial layer, and

wherein the second dielectric layer includes a material resistant to a second etch process and the sacrificial layer is adapted to be removed by the second etch process after the reflective element is formed.

50. The device of claim 49, wherein the first etch process is a dry etch and the second etch process is a wet etch.

51. The device of claim 49, wherein the sacrificial layer includes tetraethylorthosilicate.

52. The device of claim 45, wherein the second dielectric layer includes silicon carbide.

53. The device of claim 45, wherein the first dielectric layer includes tetraethylorthosilicate.

54. The device of claim 45, wherein the substructure includes a complementary metal oxide semi-conductor structure.

55. The device of claim 45, wherein the base material of the substructure includes silicon, and the at least one conductive layer of the substructure includes aluminum.

56. A display device including the micro-mirror device of claim 45.