Micromirrors with mechanisms for enhancing coupling of the micromirrors with electrostatic fields

• US 20050190430A1
• Filed: 02/25/2005
• Published: 09/01/2005
• Est. Priority Date: 08/11/2000
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Venture Lending & Leasing IV Incorporated
• Inventors: Patel, Sataydev, Huibers, Andrew
• Granted Patent: US 6,974,713 B2
• Time in Patent Office: Days
• US Class Current: 359/291
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means

Abstract

A micromirror device is disclosed, along with a method of making such a micromirror device that comprises a mirror plate, a hinge and an extension plate. The extension plate is formed on the mirror plate and between the mirror plate and the electrode associated with the mirror plate for rotating the mirror plate. The extension plate can be metallic or dielectric. Also disclosed is a method of making such a micromirror device. In particular, the extension plate is formed after the formation of the mirror plate. Moreover, also disclosed is a projection system that comprises a spatial light modulator having an array of such micromirrors, as well as a light source, condensing optics, wherein light from the light source is focused onto the array of micromirrors, projection optics for projecting light selectively reflected from the array of micromirrors onto a target, and a controller for selectively actuating the micromirrors in the array.

Claims

1-45. -45. (canceled)

46. A method of making a micromirror device, the method comprising:

depositing a first sacrificial layer on a substrate;

forming a mirror plate on the first sacrificial layer;

depositing a second sacrificial layer on the mirror plate;

forming a hinge, a hinge support and an extension plate, further comprising;

removing a first portion of the second sacrificial layer at a first location above the mirror plate so as to expose a first portion of the mirror plate; and

depositing the extension plate on the second sacrificial layer and the exposed first portion of the mirror plate; and

removing the first and the second sacrificial layers.

47. The method of claim 46, further comprising:

before forming the extension plate,

depositing a third sacrificial layer; and

forming the extension plate on the third sacrificial layer; and

the step of removing the first and the second sacrificial layers further comprising;

removing the third sacrificial layer.

48. The method of claim 46, wherein the step of forming the hinge, the hinge support and the extension plate further comprises:

removing a second portion of the second sacrificial layer at a second location above the mirror plate so as to expose a second portion of the mirror plate; and

depositing the hinge on the second sacrificial layer and the exposed second portion of the mirror plate.

49. The method of claim 46, wherein the first location is away from a center of the mirror plate.

50. The method of claim 49, wherein the second location is away from a center of the mirror plate.

51. The method of claim 46, wherein the step of removing the first and second sacrificial layer further comprises:

etching the first and second sacrificial layers using a spontaneous vapor phase etching with non-plasma spontaneous chemical vapor-phase etchant.

52. The method of claim 51, wherein the chemical vapor-phase etchant is vapor-phase interhalogen.

53. The method of claim 51, wherein the chemical vapor-phase etchant is vapor-phase noble gas halide.

54. The method of claim 53, wherein the noble gas halide is xenon difluoride.

55. A method of making a micromirror device, comprising:

depositing a first sacrificial layer on a light transmissive substrate;

forming a reflective mirror plate on the first sacrificial layer;

depositing a second sacrificial layer on the mirror plate;

forming a hinge and an extension plate on the second sacrificial layer and connected to the reflective mirror plate; and

removing the first and second sacrificial layers so as to release the micromirror device.

56. The method of claim 55, further comprising:

forming a first and second posts in the second sacrificial layers, wherein the first post connects the extension plate to the mirror plate, and the second post connects the hinge to the mirror plate.

57. The method of claim 56, wherein the location wherein the hinge is connected to the mirror plate via the second post is away from a center of the mirror plate.

58. The method of claim 56, wherein the location wherein the extension plate is connected to the mirror plate via the first post is away from a center of the mirror plate.

59. The method of claim 56, wherein the step of removing the first and second sacrificial layer further comprises:

etching the first and second sacrificial layers using a spontaneous vapor phase etching with non-plasma spontaneous chemical vapor-phase etchant.

60. The method of claim 59, wherein the chemical vapor-phase etchant is vapor-phase interhalogen.

61. The method of claim 59, wherein the chemical vapor-phase etchant is vapor-phase noble gas halide.

62. The method of claim 61, wherein the noble gas halide is xenon difluoride.

63. The method of claim 56, wherein the step of forming the hinge and the extension plate further comprises:

forming a stopping mechanism on said the other one of the first and second sacrificial layer such that the deflection of the mirror plate is operable to be stopped by the stopping mechanisms after releasing the mirror plate.

64. The method of claim 63, wherein the step of forming the hinge and the extension plate further comprises:

forming a hinge support on said the other one of the first and second sacrificial layer so as to hold the hinge on the substrate after removing the first and second sacrificial layers.

65. A method of making a micromirror device, the method comprising:

providing a substrate;

depositing first and second sacrificial layers on the substrate;

forming a reflective mirror plate on of the first and second sacrificial layers;

forming a hinge and extension plate on and first and second posts in the other one of the first and second sacrificial layers such that the hinge is connected to the mirror plate via the first post at a first location; and

the extension plate is connected to the mirror plate via the second post at the second location other than the first location in the mirror plate; and

removing the first and second sacrificial layers so as to release the mirror plate.

66. The method of claim 65, wherein the location wherein the hinge is connected to the mirror plate via the second post is away from a center of the mirror plate.

67. The method of claim 65, wherein the location wherein the extension plate is connected to the mirror plate via the first post is away from a center of the mirror plate.

68. The method of claim 65, wherein the step of removing the first and second sacrificial layer further comprises:

etching the first and second sacrificial layers using a spontaneous vapor phase etching with non-plasma spontaneous chemical vapor-phase etchant.

69. The method of claim 68, wherein the chemical vapor-phase etchant is vapor-phase interhalogen.

70. The method of claim 68, wherein the chemical vapor-phase etchant is vapor-phase noble gas halide.

71. The method of claim 70, wherein the noble gas halide is xenon difluoride.

72. The method of claim 65, wherein the step of forming the hinge and the extension plate further comprises:

forming a stopping mechanism on said the other one of the first and second sacrificial layer such that the deflection of the mirror plate is operable to be stopped by the stopping mechanisms after releasing the mirror plate.

73. The method of claim 65, wherein the step of forming the hinge and the extension plate further comprises:

forming a hinge support on said the other one of the first and second sacrificial layer so as to hold the hinge on the substrate after removing the first and second sacrificial layers.