Multiple hinge MEMS device

• US 6,950,223 B2
• Filed: 01/15/2003
• Issued: 09/27/2005
• Est. Priority Date: 01/15/2003
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Reflectivity, Inc. (Texas Instruments, Inc.)
• Inventors: Patel, Satyadev R., Huibers, Andrew G.
• Primary Examiner(s): Ben, Loha
• Application Number:
  US10/346,506
• Publication Number:
  US 20040233505A1
• Time in Patent Office: 986 Days
• Field of Search: 359/290, 359/291, 359/298, 359/214, 359/223, 359/224, 359/850, 359/196, 359/198, 257/417, 310/36, 310/90, 310/309, 310/328
• US Class Current: 359/291
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means

Abstract

A MEMS device is disclosed comprising: a substrate; a movable micromechanical element movable relative to the substrate; a connector and a hinge for allowing movement of the micromechanical element, wherein the connector is made of a material different than the hinge. In another embodiment of the invention, the connector has a conductivity greater than the hinge. In a further embodiment of the invention, the hinge provides at least 90% of the restoring force to the MEMS device, and the connector provides 10% or less of the restoring force. In a further embodiment of the invention, the connector and the hinge have different spring constants. In a still further embodiment of the invention, the connector experiences a lower strain at maximum deflection of the micromechanical element than the hinge.

Claims

1. A MEMS device comprising:

a substrate;

a movable micromechanical element movable relative to the substrate;

a hinge held on the substrate and connected to the movable micromechanical element for allowing movement of the micromechanical element, and a connector separate from the hinge for allowing electrical connection to the movable micromechanical element, wherein the hinge is made of a material different than the connector.

2. The MEMS device of claim 1, wherein the spring constant of the connector is different than the spring constant of the hinge.

3. The MEMS device of claim 2, wherein the hinge that is stiffer is insulating and the connector that is less stiff is conducting.

4. The MEMS device of claim 2, wherein the difference in the spring constants of the hinge and connector is by at least a factor of one.

5. The MEMS device of claim 3, wherein the hinge comprises a ceramic material.

6. The MEMS device of claim 5, wherein the hinge comprises a nitride or oxide of silicon.

7. The MEMS device of claim 6, wherein the connector comprises an elemental metal, conductive intermetallic compound, or a metal alloy.

8. The MEMS device of claim 7, wherein the connector comprises aluminum, titanium, titanium nitride, titanium tungsten, titanium aluminide, tungsten, copper, and mixtures thereof.

9. The MEMS device of claim 1, wherein the connector comprises a metal, intermetallic compound, conductive ceramic or metal alloy layer and the hinge comprises an insulating ceramic compound layer.

10. The MEMS device of claim 9, wherein the connector is made of aluminum, titanium, titanium tungsten, titanium nitride, titanium aluminide, tungsten, copper, and alloys;

thereof, and the hinge comprises a metal oxide, metalloid oxide, metalloid nitride or metal nitride.

11. The MEMS device of claim 1, wherein the hinge supplies at least 99% of the restoring force to the micromechanical element and the connector supplies 1% of less or the restoring force.

12. The MEMS device of claim 1, wherein a plurality hinges and connectors are provided.

13. The MEMS device of claim 12, wherein from 1 to 4 hinges and 1 to 2 hinges are provided.

14. The MEMS device of claim 1, wherein the movable micromechanical element is a micromirror for a projection display or optical switch.

15. The MEMS device of claim 1, wherein the movable micromechanical element is a MEMS switch.

16. The MEMS device of claim 1, wherein the connector is thinner than the hinge.

17. The MEMS device of claim 1, wherein the connector experiences lower maximum strain than the maximum strain of the hinge at maximum deflection.

18. The MEMS device of claim 1, wherein the connector is longer than the hinge.

19. The MEMS device of claim 1, wherein the connector has a circuitous shape and the hinge is substantially straight and elongated.

20. The MEMS device of claim 1, wherein the connector is a conductive multilayer laminate and the hinge is an insulator.

21. The MEMS device of claim 1, that is a micromirror.

22. The MEMS device of claim 21, that is a micromirror within a spatial light modulator.

23. A MEMS device comprising:

a substrate;

a movable micromechanical element held on the substrate such that the micromechanical element is movable relative to the substrate;

a connector and a hinge connecting the movable micromechanical element to the substrate for allowing movement of the micromechanical element, wherein the connector has an electrical conductivity greater than the hinge.

24. The MEMS device of claim 23, wherein a spring constant of the connector is different than a spring constant of the hinge.

25. The MEMS device of claim 24, wherein the hinge has a greater width and/or thickness than the connector.

26. The MEMS device of claim 25, wherein hinge comprises a ceramic material.

27. The MEMS device of claim 26, wherein the hinge comprises a nitride or oxide of silicon.

28. The MEMS device of claim 27, wherein the less stiff connector comprises an elemental metal, intermetallic compound, conductive ceramic or a metal alloy.

29. The MEMS device of claim 28, wherein the connector comprises aluminum, titanium, titanium tungsten, titanium aluminide, tungsten, copper, and alloys thereof.

30. The MEMS device of claim 24, wherein the difference in the spring constants of the connector and hinge is by at least a factor of one.

31. The MEMS device of claim 23, wherein the connector comprises a metal, intermetallic compound, conductive ceramic or metal alloy layer and the hinge comprises a ceramic compound layer.

32. The MEMS device of claim 31, wherein the connector is made of aluminum, titanium, titanium tungsten, titanium aluminide, tungsten, copper, and alloys thereof, and the hinge comprises a metal oxide, metalloid oxide, metalloid nitride or metal nitride.

33. The MEMS device of claim 32, wherein the hinge is a reactively sputtered metal in nitrogen or oxygen.

34. The MEMS device of claim 23, wherein a plurality of connectors and/or hinges are provided.

35. The MEMS device of claim 34, wherein from 1 to 4 hinges and 1 to 2 connectors are provided.

36. The MEMS device of claim 23, wherein the movable micromechanical element is a micromirror for a projection display or optical switch.

37. The MEMS device of claim 23, wherein the movable micromechanical element is a MEMS switch.

38. The MEMS device of claim 23, wherein the connector is thinner than the hinge.

39. The MEMS device of claim 23, wherein the connector experiences lower strain than the hinge at maximum deflection.

40. The MEMS device of claim 23, wherein the connector is longer than the hinge.

41. The MEMS device of claim 23, wherein the connector has a circuitous shape and the hinge is substantially straight.

42. The MEMS device of claim 23, wherein the connector is a conductive multilayer laminate and the hinge is an insulator.

43. The MEMS device of claim 23, that is a micromirror.

44. The MEMS device of claim 43, that is a micromirror within a spatial light modulator.

45. A MEMS device comprising:

a substrate;

a movable micromechanical element movable relative to the substrate;

a connector and a hinge held on the substrate by a plurality of posts and arranged for allowing movement of the micromechanical element, wherein the connector and hinge have different spring constants;

wherein the connector and hinge extend between the posts across the micromechanical element; and

wherein the connector and hinge are spaced apart from the micromechanical element with a gap formed therebetween.

46. The MEMS device of claim 45, further comprising circuitry and an electrode on the substrate or on a second substrate for electrostatically actuating the micromechanical element.

47. The MEMS device of claim 46, wherein from 1 to 4 hinges and 1 to 2 connectors are provided.

48. The MEMS device of claim 45, wherein the hinge is stiffer and insulating and the connector is less stiff and conducting.

49. The MEMS device of claim 48, wherein the hinge comprises a ceramic material.

50. The MEMS device of claim 49, wherein the stiffer insulating hinge comprises a nitride or oxide of silicon.

51. The MEMS device of claim 50, wherein the less stiff connector comprises an elemental metal or a metal alloy.

52. The MEMS device of claim 51, wherein the metal or metal alloy is selected from aluminum, titanium, titanium tungsten, titanium aluminide, tungsten, copper, and alloys thereof.

53. The MEMS device of claim 45, wherein the difference in the spring constants of the hinge and connector is by at least a factor of two.

54. The MEMS device of claim 45, wherein the connector comprises a metal or metal alloy layer and the hinge comprises a ceramic compound layer.

55. The MEMS device of claim 54, where the connector is made of aluminum, titanium, titanium tungsten, titanium aluminide, tungsten, copper, and alloys thereof, and the hinge comprises a metal oxide, metalloid oxide, metalloid nitride or metal nitride.

56. The MEMS device of claim 55, wherein the hinge is a reactively sputtered metal in nitrogen or oxygen.

57. The MEMS device of claim 45, wherein a plurality of connectors and/or hinges is provided.

58. The MEMS device of claim 45, wherein the movable micromechanical element is a micromirror for a projection display or optical switch.

59. The MEMS device of claim 45, wherein the movable micromechanical element is a MEMS switch.

60. The MEMS device of claim 45, wherein the connector is thinner than the hinge.

61. The MEMS device of claim 45, wherein the connector experiences lower strain than the hinge at maximum deflection.

62. The MEMS device of claim 45, wherein the connector is longer than the hinge.

63. The MEMS device of claim 45, wherein the connector has a circuitous shape and the hinge is substantially straight.

64. The MEMS device of claim 45, wherein the connector is a conductive multilayer laminate and the hinge is an insulator.

65. The MEMS device of claim 45, that is a micromirror.

66. A MEMS device comprising:

a substrate;

a movable micromechanical element movable relative to the substrate;

a connector and a hinge held on the substrate by a plurality of posts and arranged for allowing movement of the micromechanical element, wherein the connector experiences a lower strain at maximum deflection of the micromechanical element than the hinge;

wherein the connector and hinge extend between the posts across the micromechanical element; and

wherein the connector and hinge are spaced apart from the micromechanical element with a gap formed therebetween.

67. The MEMS device of claim 66, wherein a spring constant of the connector is different than a spring constant of the hinge.

68. The MEMS device of claim 67, wherein the hinge that is stiffer is insulating and the connector that is less stiff is conducting.

69. The MEMS device of claim 68, wherein the stiffer insulating hinge comprises a ceramic material.

70. The MEMS device of claim 69, wherein the stiffer insulating hinge comprises a nitride or oxide of silicon.

71. The MEMS device of claim 70, wherein the less stiff connector comprises an elemental metal, intermetallic compound, conductive ceramic or a metal alloy.

72. The MEMS device of claim 71, wherein the connector comprises aluminum, titanium, titanium tungsten, titanium aluminide, tungsten, copper, and alloys thereof.

73. The MEMS device of claim 67, wherein the difference in the spring constants of the hinges is by at least a factor of two.

74. The MEMS device of claim 66, wherein the connector comprises a metal or metal alloy layer and the hinge comprises a ceramic compound layer.

75. The MEMS device of claim 74, wherein the connector is made of aluminum, titanium, titanium tungsten, titanium aluminide, tungsten, copper, and alloys thereof, and the hinge comprises a metal oxide, metalloid oxide, metalloid nitride or metal nitride.

76. The MEMS device of claim 75, wherein the hinge is a reactively sputtered metal in nitrogen or oxygen.

77. The MEMS device of claim 66, wherein a plurality of hinges is provided.

78. The MEMS device of claim 77, that is a micromirror in a spatial light modulator.

79. The MEMS device of claim 66, wherein the movable micromechanical element is a micromirror for a projection display or optical switch.

80. The MEMS device of claim 66, wherein the movable micromechanical element is a MEMS switch.

81. The MEMS device of claim 66, wherein the connector is thinner than the hinge.

82. The MEMS device of claim 66, wherein the connector is made of a different material than the hinge.

83. The MEMS device of claim 66, wherein the connector is longer than the hinge.

84. The MEMS device of claim 66, wherein the connector has a circuitous shape and the hinge is substantially straight.

85. The MEMS device of claim 66, wherein the connector is a conductive multilayer laminate and the hinge is an insulator.

86. A MEMS device comprising:

a substrate;

a movable micromechanical element movable relative to the substrate;

a connector and a hinge for allowing movement of the micromechanical element, the hinge being an elongated hinge that connects to one or more posts on the substrate and to the movable micromechanical element, each hinge having a length in the direction of the elongation, and a width and depth; and

wherein at least one of the width and depth of the connector is different than the width or depth of the hinge.

87. The MEMS device of claim 86, wherein a spring constant of the connector is different than a spring constant of the hinge.

88. The MEMS device of claim 87, wherein the hinge that is stiffer has a greater width and/or thickness.

89. The MEMS device of claim 88, wherein the stiffer insulating hinge comprises a ceramic material.

90. The MEMS device of claim 89, wherein the stiffer insulating hinge comprises a nitride or oxide of silicon.

91. The MEMS device of claim 90, wherein the less stiff connector comprises an elemental metal, intermetallic compound, conductive ceramic or a metal alloy.

92. The MEMS device of claim 91, wherein the metal or metal alloy is selected from aluminum, titanium, titanium tungsten, titanium aluminide, tungsten, copper, and alloys thereof.

93. The MEMS device of claim 87, wherein the difference in the spring constants of the connector and hinge is by at least a factor of two.

94. The MEMS device of claim 86, wherein the connector comprises a metal or metal alloy layer and the hinge comprises a ceramic compound layer.

95. The MEMS device of claim 94, wherein the connector is made of aluminum, titanium, titanium tungsten, titanium aluminide, tungsten, copper, and alloys thereof, and the hinge comprises a metal oxide, metalloid oxide, metalloid nitride or metal nitride.

96. The MEMS device of claim 95, wherein the hinge is a reactively sputtered metal in nitrogen or oxygen.

97. A spatial light modulator comprising:

a substrate;

a post connected to the substrate;

a movable micromirror element connected to the post via a hinge such that the micromirror element is movable relative to the substrate; and

a connector separate from the hinge, wherein the hinge supplies at least 90% of the restoring force to the micromirror element and the connector supplies 10% or less of the restoring force.

98. The spatial light modulator of claim 97, wherein the hinge supplies at least 99% of the restoring force to the micromirror element and the connector supplies 1% or less of the restoring force.