Micro-electro-mechanical-system (MEMS) mirror device and methods for fabricating the same

• US 6,563,106 B1
• Filed: 08/14/2001
• Issued: 05/13/2003
• Est. Priority Date: 02/01/2000
• Status: Expired due to Term

• Current Assignee: Calient AI Incorporated
• Original Assignee: Calient Networks Incorporated
• Inventors: Lee, Seung Bok, Sink, Robert Kehl, Bowers, John Edward, MacDonald, Noel, Helkey, Roger Jonathan, Corbalis, Charles
• Primary Examiner(s): LE, QUE TAN
• Application Number:
  US09/929,900
• Time in Patent Office: 637 Days
• Field of Search: 250/216, 250/239, 250/208.1, 359/290, 359/291, 359/295, 359/223, 438/22, 174/253
• US Class Current: 250/216
• CPC Class Codes: B81B 2201/042 Micromirrors, not used as optical switches
• CPC Class Codes: B81B 3/004 Angular deflection
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means

Abstract

A micro-electro-mechanical-system (MEMS) mirror device and methods for fabricating the same allow for a large range of angular motion for a center mirror component. The large range of angular motion for a center mirror component is dictated simply by a thickness of a substrate used or a thickness of a thick film used in making a support structure to support the center mirror component. The MEMS mirror device and methods for fabricating the same allow a large number mirror devices to be fabricated on a substrate. The MEMS mirror device includes a substrate. Electrodes are formed supported by the substrate. A support structure is formed adjacent to the electrodes. A hinge pattern and a mirror pattern having a center mirror component are formed such that the support structure supports the hinge pattern and mirror pattern. The support structure also supports the hinge pattern and mirror pattern such that a bottom surface of the center mirror component in a stationary non-rotating position is capable of exceeding a height of 50 μm above the electrodes.

Claims

1. A micro-electro-mechanical-system (MEMS) mirror device fabrication method, comprising:

exposing selectively a substrate to form exposed regions and unexposed regions;

forming electrodes supported by the substrate;

forming a mirror pattern having a center mirror component and a hinge pattern supported by the substrate; and

removing portions of the substrate in the exposed regions to form a support structure from the unexposed regions such that the support structure supports the mirror pattern and hinge pattern.

2. The fabrication method of claim 1, wherein the substrate is a photosensitive glass substrate.

3. The fabrication method of claim 2, wherein exposing selectively a substrate exposes selectively the photosensitive glass substrate to form exposed regions such that the center mirror component is approximately centered of the exposed regions.

4. The fabrication method of claim 3, further comprising:

polishing the photo sensitive glass substrate after exposing selectively the photo sensitive glass substrate to retain planarity and remove any materials formed thereon.

5. The fabrication method of claim 3, wherein removing portions of the substrate includes:

etching selectively using an etching solution the exposed regions of the photosensitive glass substrate.

6. The fabrication method of claim 5, wherein the etching solution is hydro-fluoric HF acid and wherein the HF add etches more rapidly in the exposed regions than in the unexposed regions.

7. The fabrication method of claim 5, wherein etching selectively includes:

forming a protection layer over the mirror pattern and hinge pattern such that portions of the photosensitive glass substrate are exposed to allow the etching solution to reach the exposed regions of the photosensitive glass substrate; and

depositing the etching solution over the photosensitive glass such that the etching solution reaches the exposed regions of the photosensitive glass to form the support structure from the unexposed regions of the photosensitive glass.

8. The fabrication method of claim 7, further including:

removing the protection layer.

9. The fabrication method of claim 1, wherein forming the mirror pattern forms a frame pattern such that the hinge pattern supports the frame pattern.

10. The fabrication method of claim 1, wherein forming the mirror pattern forms a frame pattern and a mirror component such that the hinge pattern supports the frame pattern and mirror component.

11. The fabrication method of claim 1, wherein a thickness of the support structure is capable of exceeding a thickness of 50 μ

m.

12. The fabrication method of claim 1, wherein the mirror pattern includes at least one layer.

13. The fabrication method of claim 12, wherein the mirror pattern includes a gold Au metal layer, an aluminum Al metal layer, or a copper cu metal layer.

17. The fabrication method of claim 1, further comprising:

forming a wiring pattern such that the wiring pattern is coupled with the electrodes;

forming an insulation layer such that the insulation layer insulates the wiring pattern and electrodes.

14. The fabrication method of 12, wherein forming a mirror pattern includes:

forming a first metal layer;

forming a support layer on the first metal layer; and

forming a second metal layer on the support layer.

15. The fabrication method of claim 14, wherein the first and second metal layers are a gold Au metal layer, aluminum Al metal layer, or copper Cu metal layer.

16. The fabrication method of claim 14, wherein the support layer is a silicon dioxide SiO₂ layer, silicon nitride Si_xN_y layer, polysilicon layer, silicon oxynitride Si_xO_yN_z layer, or polymer layer.

18. A micro-electro-mechanical-system (MEMS) mirror device fabrication method, comprising:

forming a release layer on a first substrate;

forming a mirror pattern having a center mirror component and a hinge pattern supported by the release layer;

forming electrodes supported by a second substrate;

forming a support structure;

attaching the first substrate with the second substrate using the support structure;

removing the first substrate and the release layer such that the support structure supports the hinge pattern and mirror pattern.

19. The fabrication method of claim 18, wherein forming a support structure forms the support structure such that the support structure is supported by the second substrate.

20. The fabrication method of claim 19, wherein forming a support structure includes;

forming a bond with a topside of the support structure with the hinge pattern supported by the first substrate such that the first substrate is attached with the second substrate.

21. The fabrication method of claim 18, wherein forming a support structure forms the support structure such that the support structure is supported by the first substrate.

22. The fabrication method of claim 21, wherein forming a support structure includes:

forming a bond with a topside of the support structure with the second substrate such that first substrate is attached with the second substrate.

23. The fabrication method of claim 18, wherein forming the support structure uses a thick patterned film.

24. The fabrication method of claim 23, wherein forming the support structure uses an electroless, electro-plating, or a sputtering process with the thick patterned film to form the support structure.

25. The fabrication method of claim 24, wherein the thickness of the thick patterned film dictates the thickness of the support structure.

26. The fabrication method of claim 25, wherein forming the support structure uses nickel Ni, copper Cu, gold Au, or aluminum Al.

27. The fabrication method of claim 18, wherein the release layer is a polymer layer, oxide layer, or a nitride layer.

28. The fabrication method of claim 27, wherein removing the first substrate and release layer includes:

etching away the first substrate using an etching solution; and

applying oxygen plasma to react with the release layer such that the release layer is removed from the mirror pattern.

29. The fabrication method of claim 27, wherein removing the release layer includes:

etching away the release layer such that the release layer is removed from the mirror pattern.

30. The fabrication method of claim 18, wherein the first substrate is a silicon substrate, glass substrate, or borosilicate glass substrate.

31. The fabrication method of claim 18, wherein forming a mirror pattern forms a frame pattern supported by the release layer.

32. The fabrication method of claim 18, wherein forming a mirror pattern forms a frame pattern and a mirror component supported by the release layer.

33. The fabrication method of claim 18, wherein the mirror pattern includes at least one layer.

34. The fabrication method of claim 33, wherein the mirror pattern includes a gold Au metal layer, an aluminum Al metal layer, or a copper Cu metal layer.

35. The fabrication method of claim 33, wherein forming a mirror pattern includes:

forming a first metal layer on the release layer;

forming a support layer on the first metal layer; and

forming a second metal layer on the support layer.

36. The fabrication method of claim 35, wherein the first and second metal layers are a gold Au metal layer, aluminum Al metal layer, or copper Cu metal layer.

37. The fabrication method of claim 36, wherein the support layer is silicon dioxide SiO₂ layer, silicon nitride Si_xN_y layer, polysilicon layer, silicon oxynitride Si_xO_yN_z layer, or polymer layer.

38. The fabrication method of claim 18, further comprising:

forming a wiring pattern such that the wiring pattern is coupled with the electrodes; and

forming an insulation layer insulating the wiring pattern and electrodes.

39. A micro-electro-mechanical-system (MEMS) mirror device fabrication method, comprising:

forming a release layer on a first substrate;

forming a mirror pattern having a center mirror component and a hinge pattern supported by the release layer;

forming electrodes supported by a second substrate;

forming a support structure using a third substrate;

attaching the first substrate with the second substrate using the support structure;

removing the first substrate and release layer.

40. The fabrication method of claim 39, wherein the release layer is a polymer layer, oxide layer, or a nitride layer.

41. The fabrication method of claim 40, wherein removing the first substrate and release layer includes:

etching away the first substrate using an etching solution, and

applying oxygen plasma to react with the release layer such that the release layer is removed from the mirror pattern.

42. The fabrication method of claim 40, wherein removing the release layer includes:

etching away the release layer such that the release layer is removed from the mirror pattern.

43. The fabrication method of claim 39, wherein forming a mirror pattern forms a frame pattern supported by the release layer.

44. The fabrication method of claim 39, wherein forming a mirror pattern forms a frame pattern and a mirror component supported by the release layer.

45. The fabrication method of claim 39, wherein the mirror pattern includes at least one layer.

46. The fabrication method of claim 45, wherein the mirror pattern includes a gold Au metal layer, an aluminum Al metal layer, or a copper Cu metal layer.

47. The fabrication method of claim 45, wherein forming a mirror pattern includes:

forming a first metal layer;

forming a support layer on the first metal layer; and

forming a second metal layer on the support layer.

48. The fabrication method of claim 47, wherein the first and second metal layers are a gold Au metal layer, aluminum Al metal layer, or copper Cu metal layer.

49. The fabrication method of claim 47, wherein the support layer is silicon dioxide SiO₂ layer, silicon nitride Si_xN_y layer, polysilicon layer, silicon oxynitride Si_xO_yN_z layer, or polymer layer.

50. The fabrication method of claim 39, wherein the third substrate is a silicon substrate or a photosensitive glass substrate.

51. The fabrication method of claim 50, wherein forming a support structure includes:

exposing selectively the photosensitive glass substrate to form exposed regions and unexposed regions in the photosensitive glass substrate; and

removing portions of the photosensitive glass substrate in the exposed regions to form the support structure from the unexposed regions such that the support structure supports the hinge pattern and mirror pattern.

52. The fabrication method of claim 50, wherein forming a support structure includes:

etching deep holes in the silicon substrate such that the remaining portions of the silicon substrate form the support structure.

53. The fabrication method of claim 39, wherein a thickness of the third substrate dictates the thickness of the support structure, and wherein the thickness of the support structure is capable of exceeding a thickness of 50 μ

m.

54. The fabrication method of claim 39, further comprising:

forming a wiring pattern such that the wiring pattern is coupled with the electrodes; and

forming an insulation layer insulating the wiring pattern and electrodes.

55. A micro-electro-mechanical-system (MEMS) mirror device fabrication method, comprising:

forming electrodes supported by a first substrate;

removing selectively portions of a second substrate on a bottom side;

removing selectively portions of the second substrate on a topside to form a mirror pattern, frame pattern, hinge pattern, and support structure; and

attaching the first substrate with the second substrate.

56. The fabrication method of claim 55, wherein the second substrate is a silicon substrate or a single-crystal silicon substrate.

57. The fabrication method of claim 55, wherein removing selectively portions of a second substrate on a bottom side includes:

etching selectively the bottom side of the second substrate using an reactive ion etching RIE process, wet etch process, or a laser ablation process.

58. The fabrication method of claim 55, further comprising:

forming at least one layer on the mirror.

59. The fabrication method of claim 58, wherein the at least one layer is a gold Au metal layer, aluminum Al metal layer, or a copper Cu metal layer.

60. The fabrication method of claim 55, further comprising:

forming at least one layer on the mirror and frame pattern.

61. The fabrication method of claim 60, wherein the at least one layer is a gold Au metal layer, aluminum Al metal layer, or a copper Cu metal layer.

62. The fabrication method of claim 55, wherein the hinge pattern is formed such that the hinge pattern has a smaller thickness than the mirror and frame pattern.

63. The fabrication method of claim 62, wherein removing selectively portions of the second substrate on a topside to form the hinge pattern includes:

releasing the hinge pattern from the second substrate such that the hinge pattern is supported by the support structure.

64. The fabrication method of claim 63, wherein removing selectively portions of the second substrate on a topside to form the mirror and the frame pattern includes:

releasing the mirror and the frame pattern from the second substrate such that frame pattern is supported by the hinge pattern and the mirror is supported by the frame pattern.

65. The fabrication method of claim 55, wherein the hinge pattern, the mirror, and frame pattern have the same thickness.

66. The fabrication method of claim 65, wherein removing selectively portions of the second substrate on a topside to form the hinge pattern, mirror, and frame pattern include:

releasing the hinge pattern, mirror, and frame pattern from the second substrate such that the hinge pattern is supported by the support structure, the frame pattern is supported by the hinge pattern, and the mirror is supported by the frame pattern.

67. The fabrication method of claim 55, wherein a thickness of the support structure is capable of exceeding a thickness of 50 μ

m.

68. The fabrication method of claim 55, further comprising:

forming a wiring pattern such that the wiring pattern is coupled with the electrodes; and

forming an insulation layer insulating the wiring pattern and electrodes.