MEMS optical cross-connect switch

• US 6,396,975 B1
• Filed: 01/21/2000
• Issued: 05/28/2002
• Est. Priority Date: 01/21/2000
• Status: Expired due to Term

• Current Assignee: Memscap Incorporated
• Original Assignee: JDS Uniphase Corporation (Lumentum Holdings Inc.)
• Inventors: Wood, Robert L., Hill, Edward A., Mahadevan, Ramaswamy
• Primary Examiner(s): Palmer, Phan T. H.
• Application Number:
  US09/489,264
• Time in Patent Office: 858 Days
• Field of Search: 385/16,17,18-24,6,33 359/223,196,117
• US Class Current: 385/18
• CPC Class Codes: G02B 26/085 the reflecting means being moved or deformed by electromagnetic means
• CPC Class Codes: G02B 6/3512 the optical element being reflective, e.g. mirror
• CPC Class Codes: G02B 6/3546 NxM switch, i.e. a regular array of switches elements of matrix type constellation
• CPC Class Codes: G02B 6/3572 Magnetic force magnetic forces controlling reflecting elements in general G02B26/085; magneto-optic devices G02F1/09
• CPC Class Codes: G02B 6/3582 Housing means or package or arranging details of the switching elements, e.g. for thermal isolation
• CPC Class Codes: G02B 6/3584 constructional details of an associated actuator having a MEMS construction, i.e. constructed using semiconductor technology such as etching MEMS per se B81B, B81C

Abstract

A microelectromechanical structure capable of switching optical signals from an input fiber to one of two or more output fibers. In one embodiment, the MEMS optical cross-connect switch comprises a first microelectronic substrate having a pop-up mirror disposed on the surface of the substrate and a rotational magnetic field source, such as a variably controlled magnetic field source. The rotational magnetic field source allows for reliable actuation of the pop-up mirror from a non-reflective state to a reflective state. Additionally the invention is embodied in a MEMS optical cross-connect switch having a first microelectronic substrate having a pop-up mirror disposed on the surface of the substrate and a positioning structure disposed in a fixed positional relationship relative to the first substrate. The positioning structure may comprise a positioning structure extending from a second microelectronic substrate that is in a fixed positional relationship relative to the first microelectronic substrate. The positioning structure serves to restrict further movement of the pop-up mirror when the pop-up mirror has been actuated into a reflective state.

Claims

1. A MEMS optical cross-connect switch comprising:

a first microelectronic substrate having a first surface;

a pop-up mirror disposed on the first surface;

a rotational magnetic field source disposed proximate the first microelectronic substrate that actuates the pop-up mirror; and

a second microelectronic substrate disposed in a fixed positional relationship relative to said first microelectronic substrate, said second microelectronic substrate having at least one positioning structure for positioning said pop-up mirror in a reflective state.

2. The MEMS optical cross-connect switch of claim 1, wherein said rotational magnetic field source further comprises a plurality of magnetic field sources.

3. The MEMS optical cross-connect switch of claim 2, wherein said plurality of magnetic field sources further comprises a first and a second magnetic field source.

4. The MEMS optical cross-connect switch of claim 3, wherein the first magnetic field source generates a first magnetic field component disposed at a predetermined angle relative to a second magnetic field component generated by the second magnetic field source.

5. The MEMS optical-cross connect switch of claim 3, wherein the first magnetic field source generates a first magnetic field component generally orthogonal to the second magnetic field component generated by the second magnetic field source.

6. The MEMS optical cross-connect switch of claim 3, wherein the first magnetic field source generates a first magnetic field component generally perpendicular to the first surface of said first microelectronic substrate and the second magnetic field source generates a second magnetic field component generally parallel to the first surface of the first microelectronic substrate.

7. The MEMS optical cross-connect switch of claim 2, wherein the plurality of magnetic field sources further comprise conductive coils.

8. The MEMS optical cross-connect switch of claim 2, wherein said plurality of magnetic field sources further comprises variably controlled magnetic field sources.

9. The MEMS optical cross-connect switch of claim 2, wherein said plurality of magnetic field sources generate a composite magnetic field axis urging movement of said pop-up mirror.

10. MEMS optical cross-connect switch of claim 2, wherein said plurality of magnetic field sources generate an initial composite magnetic field axis that is about 45 degrees askew to the first surface of the first microelectronic substrate.

11. The MEMS optical cross-connect switch of claim 1, wherein said at least one positioning structure further comprises at least one positioning structure extending from said second microelectronic substrate toward the first surface of said first microelectronic substrate.

12. The MEMS optical cross-connect switch of claim 11, wherein said pop-up mirror is positioned in a reflective state by contacting at least one tab structure of said pop-up mirror with the at least one positioning structure.

13. The MEMS optical cross-connect switch of claim 11, wherein said pop-up mirror is positioned in a reflective state by contacting a top tab of said pop-up mirror with at least one positioning structure.

14. The MEMS optical cross-connect switch of claim 11, wherein said at least one positioning structure has a cross-sectional shape that allows for unobstructed passage of optical signals.

15. The MEMS optical cross-connect switch of claim 11, wherein said at least one positioning structure has a generally trapezoidal cross-sectional shape.

16. The MEMS optical cross-connect switch of claim 1, further comprising a tether device selectively operable for attracting said pop-up mirror to said first microelectronic substrate.

17. The MEMS optical cross-connect switch of claim 16, wherein said tether device further comprises an anchor portion attached to the first microelectronic substrate and a hairpin portion attached to the anchor and released from the first microelectronic substrate.

18. The MEMS optical cross-connect switch of claim 16, wherein said tether device is capable of electrostatic activation to retain said pop-up mirror in a predetermined position with respect to the first surface of the first microelectronic substrate.

19. The MEMS optical cross-connect switch of claim 1, wherein said at least one positioning structure further comprises a recess in the second microelectronic substrate that allows for said pop-up mirror to be positioned in a reflective state by having a tab structure of said pop-up mirror contact an interior surface of the recess.

20. The MEMS optical cross-connect switch of claim 1, wherein said at least one positioning structure is capable of being electrostatically activated to provide a voltage to clamp said pop-up mirror in a reflective state.

21. The MEMS optical cross-connect switch of claim 1, wherein said rotational magnetic field source provides for a magnetic field oriented with respect to said first microelectronic substrate to interact with said pop-up mirror.

22. The MEMS optical cross-connect switch of claim 4 wherein said rotational magnetic field source actuates the pop-up mirror from a non-reflective state to the reflective state.

23. The MEMS optical cross-connect switch of claim 1, wherein said second microelectronic substrate comprises a material having precision surface facing capabilities.

24. The MEMS optical cross-connect switch of claim 1, wherein said second microelectronic substrate comprises <

110>

crystal silicon.

25. A MEMS optical cross-connect switch comprising:

a first microelectronic substrate having a first surface;

a pop-up mirror disposed on the first surface; and

a rotational magnetic field source disposed proximate the first microelectronic substrate that actuates the pop-up mirror,

wherein said pop-up mirror further comprises at least one or more materials capable of optical reflectivity and magnetic activity.

26. A MEMS optical cross-connect switch comprising:

a first microelectronic substrate having a first surface;

a pop-up mirror disposed on the first surface; and

a rotational magnetic field source disposed proximate the first microelectronic substrate that actuates the pop-up mirror,

wherein said pop-up mirror further comprises an outlying frame portion attached about the periphery of said pop-up mirror.

27. A MEMS optical cross-connect switch comprising:

a first microelectronic substrate having a first surface;

a pop-up mirror disposed on the first surface and that rotates from a non-reflective state to a reflective state; and

a positioning structure disposed in a fixed positional relationship relative to the first microelectronic substrate, wherein said positioning structure engages said pop-up mirror upon rotation of said pop-up mirror to the reflective state,

wherein said positioning structure further comprises a positioning structure extending from a second microelectronic substrate, wherein the second microelectronic substrate is disposed in a fixed positional relationship relative to the first microelectronic substrate.

28. The MEMS optical cross-connect switch of claim 27, further comprising a plurality of magnetic field sources.

29. The MEMS optical cross-connect switch of claim 28, wherein said plurality of magnetic field sources further comprises variably controlled magnetic field sources capable of generating a rotational magnetic field.

30. The MEMS optical cross-connect switch of claim 28, wherein said plurality of magnetic field sources generates a composite magnetic field axis urging movement of said pop-up mirror.

31. The MEMS optical cross-connect switch of claim 28, wherein said plurality of magnetic field sources generates an initial composite magnetic field axis that is about 45 degrees askew to the first surface of the first microelectronic substrate.

32. The MEMS optical cross-connect switch of claim 28, wherein the plurality of magnetic field sources further comprise conductive coils.

33. The MEMS optical cross-connect switch of claim 27, further comprising a tether device selectively operable for attracting said pop-up mirror to said first microelectronic substrate.

34. The MEMS optical cross-connect switch of claim 33, wherein said tether device is electrostatically activated to retain the pop-up mirror in a predetermined position with respect to the first surface of the first microelectronic substrate.

35. The MEMS optical cross-connect switch of claim 33, wherein said tether device further comprises an anchor portion attached to the first microelectronic substrate and a hairpin portion attached to the anchor and released from the underlying first microelectronic substrate.

36. The MEMS optical cross-connect switch of claim 27, wherein said positioning structure extends toward said first microelectronic substrate and is electrically isolated from said first microelectronic substrate by an air gap.

37. The MEMS optical cross-connect switch of claim 27, further comprising a magnetic field source that provides for a magnetic field oriented with respect to the said first microelectronic substrate to interact with said pop-up mirror.

38. The MEMS optical cross-connect switch of claim 27, wherein said positioning structure has a cross-sectional shape that allows for unobstructed passage of optical signals.

39. The MEMS optical cross-connect switch of claim 27, wherein said positioning structure has a generally trapezoidal cross-sectional shape.

40. The MEMS optical cross-connect switch of claim 27, wherein the positioning structure is electrostatically activated to provide voltage to clamp said pop-up mirror in a reflective state.

41. The MEMS optical cross-connect switch of claim 27, further comprising a second positioning structure that positions said pop-up mirror when said pop-up mirror has been actuated.

42. The MEMS optical cross-connect switch of claim 27, wherein the second positioning structure is electrostatically activated to provide voltage to clamp said pop-up mirror in a reflective state.

43. The MEMS optical cross-connect switch of claim 27, further comprising a magnetic pole piece disposed proximate to said second microelectronic substrate to further the magnetic actuation of said pop-up mirror.

44. A MEMS optical cross-connect switch comprising:

a first microelectronic substrate having a first surface;

a pop-up mirror disposed on the first surface and that rotates from a non-reflective state to a reflective state;

a positioning structure disposed in a fixed positional relationship relative to the first microelectronic substrate, wherein said positioning structure engages said pop-up mirror upon rotation of said pop-up mirror to the reflective state; and

a plurality of magnetic field sources wherein said plurality of magnetic field sources further comprises a first and a second magnetic field source.

45. The MEMS optical cross-connect switch of claim 44, wherein the first magnetic field source generates a first magnetic field component disposed at a predetermined angle relative to a second magnetic field component generated by the second magnetic field source.

46. The MEMS optical-cross connect switch of claim 44, wherein the first magnetic field source generates a first magnetic field component generally orthogonal to the second magnetic field component generated by the second magnetic field source.

47. The MEMS optical cross-connect switch of claim 44, wherein the first magnetic field source generates a first magnetic field component generally perpendicular to the first surface of said first microelectronic substrate and the second magnetic field source generates a second magnetic field component generally parallel to the first surface of the first microelectronic substrate.

48. A MEMS optical cross-connect switch comprising:

a first microelectronic substrate having a first surface;

a pop-up mirror disposed on the first surface and that rotates from a non-reflective state to a reflective state; and

a positioning structure disposed in a fixed positional relationship relative to the first microelectronic substrate, wherein said positioning structure engages said pop-up mirror upon rotation of said pop-up mirror to the reflective state,

wherein said pop-up mirror further comprises at least one or more materials capable of optical reflectivity and magnetic activity.

49. A MEMS optical cross-connect switch comprising:

a first microelectronic substrate having a first surface;

a pop-up mirror disposed on the first surface and that rotates from a non-reflective state to a reflective state; and

a positioning structure disposed in a fixed positional relationship relative to the first microelectronic substrate, wherein said positioning structure engages said pop-up mirror upon rotation of said pop-up mirror to the reflective state,

wherein said pop-up mirror further comprises a frame portion attached along the periphery of said pop-up mirror.

50. The MEMS optical cross-connect switch of claim 49, wherein said frame portion is magnetically active.

51. A MEMS optical cross-connect switch comprising:

a first microelectronic substrate having, a first surface,

a magnetically active pop-up mirror disposed on the first surface wherein said pop-up mirror remains in a position generally parallel to the first surface of said first microelectronic substrate when electrostatic voltage is applied to said pop-up mirror,

a second microelectronic substrate disposed in a fixed positional relationship relative to said first microelectronic substrate, said second microelectronic substrate having at least two positioning structures extending from said second microelectronic substrate toward the first surface of said first microelectronic substrate, wherein said at least two positioning structures serve to restrict further movement of said pop-up mirror and electrostatically clamp said pop-up mirror in a stationary position when the pop-up mirror has been activated to allow for optical signal reflection, and

a magnetic field source disposed about said first and second microelectronic substrate such that a magnetic field may be activated to propel said pop-up mirror into a position that allows for the pop-up mirror to be electrostatically clamped to the at least two positioning structures.

52. The MEMS optical cross-connect switch of claim 51, wherein said magnetic field source further comprises a rotational magnetic field source.

53. The MEMS optical cross-connect switch of claim 51, further comprising a magnetic pole piece disposed proximate to said second microelectronic substrate, wherein the magnetic pole piece provides additional magnetic force to the pop-up mirror.

54. A MEMS optical cross-connect switch array comprising:

a first microelectronic substrate having a first surface;

at least two pop-up mirrors disposed on the first surface of the first microelectronic substrate;

a rotational magnetic field source disposed proximate the first microelectronic substrate; and

a second microelectronic substrate disposed in a fixed positional relationship relative to said first microelectronic substrate, said second microelectronic substrate having at least two positioning structures for positioning said pop-up mirror in a reflective state.

55. The MEMS optical cross-connect switch array of claim 54, wherein the at least two pop-up mirrors further comprise n² pop-up mirrors aligned in n columns and n rows.

56. The MEMS optical cross-connect switch array of claim 54, wherein the at least two pop-up mirrors further comprise n×

m pop-up mirrors aligned in n columns and m rows.

57. The MEMS optical cross-connect switch array of claim 54, further comprising at least two positioning structures disposed on the surface of said first microelectronic substrate for positioning said at least two pop-up mirrors in reflective states.

58. The MEMS optical cross-connect switch array of claim 54, further comprising at least two magnetic pole pieces disposed proximate to said second microelectronic substrate, wherein the at least two magnetic pole pieces provide magnetic attraction for the at least two pop-up mirrors.

59. A MEMS optical cross-connect switch array comprising

a first microelectronic substrate having a first surface;

at least two pop-up mirrors disposed on the first surface of the first microelectronic substrate; and

a second microelectronic substrate disposed in a fixed positional relationship relative to said first microelectronic substrate, said second microelectronic substrate having at least two positioning structures extending from said second microelectronic substrate toward the first surface of said first microelectronic substrate, wherein said at least two positioning structures serve to restrict further movement of said at least two pop-up mirrors when the pop-up mirrors have been activated to allow for optical signal reflection.

60. The MEMS optical cross-connect switch array of claim 59, further comprising a plurality of magnetic field sources.

61. The MEMS optical cross-connect switch array of claim 60, wherein said plurality of magnetic field sources further comprises variably controlled magnetic field sources capable of generating a rotational magnetic field.

62. The MEMS optical cross-connect switch array of claim 60, wherein said plurality of magnetic field sources generates a composite magnetic field axis, urging movement of said at least two pop-up mirrors.

63. The MEMS optical cross-connect switch array of claim 60, further comprising at least two magnetic pole pieces disposed proximate the second microelectronic substrate, wherein the at least two magnetic pole pieces provide further magnetic attraction for the at least two pop-up mirrors.

64. The MEMS optical cross-connect switch array of claim 59, further comprising a magnetic field source that provides for a magnetic field oriented with respect to the said first microelectronic substrate to interact with said at least two pop-up mirrors.

65. The MEMS optical cross-connect switch array of claim 64, further comprising at least two magnetic pole pieces disposed proximate the second microelectronic substrate, wherein the at least two magnetic pole pieces provide magnetic attraction for the at least two pop-up mirrors.

66. The MEMS optical cross-connect switch array of claim 59, wherein the at least two pop-up mirrors further comprise n² pop-up mirrors aligned in n columns and rows.

67. The MEMS optical cross-connect switch array of claim 59, wherein the at least two pop-up mirrors further comprise n×

m pop-up mirrors aligned in n columns and m rows.

68. The MEMS optical cross-connect switch array of claim 59, wherein the at least two pop-up mirrors further comprise n² pop-up mirrors aligned in n columns and n rows, and the at least two positioning structures further comprise (n²+n+(n−

1)) positioning structures aligned in n+1 columns and n+1 rows, wherein n is a whole number greater than one.

69. The MEMS optical cross-connect switch array of claim 59, wherein said at least two positioning structures are electrically isolated from said first microelectronic substrate by an air gap.

70. The MEMS optical cross-connect switch array of claim 59, wherein said at least two positioning structures have a cross-sectional shape that allows for unobstructed passage of optical signals.

71. The MEMS optical cross-connect switch array of claim 59, wherein said at least two positioning structures have a generally trapezoidal cross-sectional shape.

72. The MEMS optical cross-connect switch array of claim 59, wherein said at least two positioning structures are electrostatically activated to provide voltage to clamp said pop-up mirror in a reflective state.

73. A MEMS optical cross-connect switch array comprising:

a first microelectronic substrate having a first surface,

at least two pop-up mirrors disposed on the first surface of the first microelectronic substrate;

a second microelectronic substrate disposed in a fixed positional relationship relative to said first microelectronic substrate,

a magnetic field source that provides for a magnetic field oriented with respect to the said first microelectronic substrate to interact with said at least two pop-up mirrors; and

at least two magnetic pole pieces disposed proximate to said second microelectronic substrate, wherein the at least two magnetic pole pieces provide for further magnetic attraction of the pop-up mirror.

74. The MEMS optical cross-connect switch array of claim 73, wherein said second microelectronic substrate provides for at least two positioning structures extending from said second microelectronic substrate toward the first surface of said first microelectronic substrate, wherein said at least two positioning structures serve to restrict further movement of said at least two pop-up mirrors when the pop-up mirrors have been activated to allow for optical signal reflection.

75. A MEMS optical cross-connect switching system comprising:

a first microelectronic substrate having a first surface;

at least one optical fiber input disposed about the perimeter of the first microelectronic substrate;

at least two optical fiber outputs disposed about the perimeter of the first microelectronic chip;

at least one pop-up mirror disposed on the first surface;

a rotational magnetic field source disposed proximate the first microelectronic substrate, wherein the rotational magnetic field source actuates the at least one pop-up mirror from a non-reflective to non-reflective state; and

a second microelectronic substrate disposed in a fixed positional relationship relative to said first microelectronic substrate, said second microelectronic substrate having at least one positioning structure extending from said second microelectronic substrate toward the first surface of said first microelectronic substrate, wherein said at least one positioning structure serves to restrict further movement of said at least one pop-up mirror when the at least one pop-up mirror has been activated to allow for optical signal reflection.

76. The MEMS optical cross-connect switching system of claim 75, wherein said at least one positioning structure is electrostatically activated to provide voltage to clamp said at least one pop-up mirror in a reflective state.

77. The MEMS optical cross-connect switching system of claim 75, further comprising at least one magnetic pole piece disposed proximate the second microelectronic substrate, wherein the at least one magnetic pole piece provides further magnetic attraction to the at least one pop-up mirror.

78. The MEMS optical cross-connect switching system of claim 75, wherein at least one optical fiber output is disposed about the perimeter generally orthogonal to the at least one optical fiber input and at least one optical fiber output is disposed about the perimeter generally 180 degrees opposite the at least one optical fiber input.

79. The MEMS optical cross-connect switching system of claim 75, wherein the at least one pop-up mirror is oriented at a generally 45 degree angle in respect to the at least one optical fiber input.

80. A MEMS optical cross-connect switching system comprising:

a first microelectronic substrate having a first surface

at least one optical fiber input disposed about the perimeter of the first microelectronic chip;

at least two optical fiber outputs disposed about the perimeter of the first microelectronic chip;

at least one pop-up mirror disposed on the first surface, and

a second microelectronic substrate disposed in a fixed positional relationship relative to said first microelectronic substrate, said second microelectronic substrate having at least one positioning structure extending from said second microelectronic substrate toward the first surface of said first microelectronic substrate, wherein said at least one positioning structure serves to restrict further movement of said at least one pop-up mirror when the at least one pop-up mirror has been activated to allow for optical signal reflection.

81. The MEMS optical cross-connect switching system of claim 80, further comprising a magnetic field source that provides for a magnetic field oriented with respect to the said first microelectronic substrate and said second microelectronic substrate to interact with said at least one pop-up mirror.

82. The MEMS optical cross-connect switching system of claim 81, wherein said magnetic field source further comprises a variably controlled magnetic field source capable of generating a rotational magnetic field.

83. The MEMS optical-cross-connect switching system of claim 82, further comprising at least one magnetic pole piece disposed proximate the second microelectronic substrate, wherein the at least one magnetic pole piece provides further magnetic attraction to the at least one pop-up mirror.

84. The MEMS optical cross-connect switching system of claim 80, wherein said at least one positioning structure is electrostatically activated to provide voltage to clamp said at least one pop-up mirror in a reflective state.

85. A MEMS optical switch comprising:

a microelectronic substrate;

a pop-up mirror disposed on a surface of the microelectronic substrate and configured to rotate between first and second angular positions with respect to the surface of the substrate;

a rotational magnetic field source disposed proximate the microelectronic substrate that rotates the pop-up mirror between the first and second angular positions; and

a positioning structure having a surface that contacts the pop-up mirror as the pop-up mirror is rotated to the second position.

86. The MEMS optical switch of claim 85, wherein the microelectronic substrate comprises a first microelectronic substrate, wherein the MEMS optical switch further comprises a second microelectronic substrate disposed substantially parallel to the first microelectronic substrate, and wherein the positioning structure comprises a member that extends from the second microelectronic substrate towards the first microelectronic substrate.

87. The MEMS optical switch of claim 86, wherein the member does not contact the surface of the first microelectronic substrate.

88. The MEMS optical switch of claim 86, further comprising an insulating layer in contact with the member and the first microelectronic substrate.

89. The MEMS optical switch of claim 85, wherein the first position comprises a first angular displacement with respect to the surface of the microelectronic substrate, wherein the second position comprises a second angular displacement with respect to the microelectronic substrate that is greater than the first angular displacement, and wherein the rotational magnetic field source is operative to apply a magnetic force to the pop-up mirror that increases as the pop-up mirror rotates from the first position towards the second position.

90. The MEMS optical switch of claim 89, wherein the rotational magnetic field source comprises a first magnet that generates a first rotational force on the pop-up mirror and a second magnet that produces an additive second rotational force on the pop-up mirror as the pop-up mirror rotates toward the second position.

91. The MEMS optical switch of claim 85, wherein the first position comprises a first angular displacement with respect to the surface of the microelectronic substrate, wherein the second position comprises a second angular displacement with respect to the microelectronic substrate that is greater than the first angular displacement, and wherein the rotational magnetic field source comprises an electromagnet assembly that produces a rotating magnetic field.

92. The MEMS optical switch of claim 85, further comprising means for electrostatically retaining the pop-up mirror in at least one of the first position and the second position.

93. The MEMS optical switch of claim 85, wherein the pop-up mirror is configured to rotate between the first and second angular positions about an axis parallel to the surface of the substrate.

94. A method for cross-connect switching of optical signals in a microelectronic device, the method comprising the steps of:

receiving an input signal on an optical path;

generating a rotational magnetic field to actuate a pop-up mirror from a non-reflective state to a reflective state;

reflecting the input signal off the pop-up mirror on another optical path;

maintaining position of the pop-up mirror at the reflective state; and

restricting the actuation of the pop-up mirror with at least one positioning structure extending from a second microelectronic substrate toward the first microelectronic substrate.

95. The method of claim 94, wherein the optical path is generally parallel to a surface of a first microelectronic substrate having the pop-up mirror disposed on the surface.

96. The method of claim 94, further comprising the step of clamping electrostatically the actuated pop-up mirror in a reflective state by applying voltage to at least one positioning structure.

97. A method for making an optical cross connect switch, the method comprising the steps of:

disposing at least one pop-up mirror on the surface of a first microelectronic substrate,

defining at least one positioning structure within a second microelectronic substrate; and

positioning the first microelectronic substrate in a fixed relationship with the second microelectronic substrate such that the at least one positioning structure of the second microelectronic substrate serves to impede further actuation of the at least one pop-up mirror beyond the reflective state.

98. The method of claim 97, further comprising the step of providing for electrostatic voltage to be applied to the at least one positioning structure to allow the at least one pop-up mirror to be electrostatically clamped to the at least one positioning structure in the reflective state.

99. The method of claim 97, wherein the step of defining at least one positioning structure in the surface of the second microelectronic substrate, further comprises the steps of:

etching anisotropically at least one opening in the second microelectronic substrate that will define a precision facing of the at least one positioning structure,

creating an oxide barrier in the at least one opening to protect the precision facing of the at least one positioning structure,

performing a deep reactive ion etch to define the remaining structure of the at least one positioning structure;

removing the oxide barrier in the at least one opening, and

re-oxidizing the second microelectronic substrate.