Compatible MEMS switch architecture

• US 20080121503A1
• Filed: 11/02/2006
• Published: 05/29/2008
• Est. Priority Date: 11/02/2006
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Sampsell, Jeffrey B.
• Granted Patent: US 7,684,106 B2
• Time in Patent Office: Days
• US Class Current: 200/181
• CPC Class Codes: G02B 26/001 based on interference in an adjustable optical cavity interference filters G02B5/28; devices or arrangements using multiple reflections in spectrometry or monochromators G01J3/26
• CPC Class Codes: G09G 3/207 by domain size control G09G3/3637 takes precedence
• CPC Class Codes: G09G 3/3466 based on interferometric effect

Abstract

A method of fabricating a display device includes forming a switch and forming a plurality of display elements in parallel electrical communication with the switch. The switch includes an electrode, a first contact, and a second contact. The switch is responsive to voltages applied to the electrode to selectively place the first contact and the second contact in communication with one another. Forming the switch includes a first set of patterning steps. Forming the plurality of display elements includes a second set of patterning steps. The second set of patterning steps includes the first set of patterning steps.

Claims

1. A method of fabricating a display device, the method comprising:

forming a switch comprising an electrode, a first contact, and a second contact, the switch responsive to voltages applied to the electrode to selectively place the first contact and the second contact in communication with one another, wherein forming the switch comprises a first set of patterning steps; and

forming a plurality of display elements in parallel electrical communication with the switch, wherein forming the plurality of display elements comprises a second set of patterning steps, the second set of patterning steps comprising the first set of patterning steps.

2. The method of claim 1, wherein the plurality of display elements comprises a plurality of interferometric modulators.

3. The method of claim 1, wherein the first contact is responsive to the voltages applied to the electrode to selectively move between a first position in which the first contact and the second contact are not in communication with one another and a second position in which the first contact and the second contact are in communication with one another.

4. The method of claim 1, wherein the switch further comprises a third contact and wherein the first contact is responsive to the voltages applied to the electrode to selectively move between a first position in which the second and third contacts are not in communication with one another and a second position in which the second and third contacts are in communication with one another through the first contact.

5. The method of claim 1, wherein the first set of patterning steps comprises:

a first patterning step that forms an electrode in each of the display elements and that forms the electrode and the second contact in the switch;

a second patterning step that forms an insulating layer over the electrode in each of the display elements and that forms an insulating layer over the electrode in the switch;

a third patterning step that forms a first sacrificial layer over the electrode in each of the display elements;

a fourth patterning step that forms a second sacrificial layer over the electrode in each of the display elements and that forms a second sacrificial layer over the electrode in the switch;

a fifth patterning step that forms a third sacrificial layer over the electrode in each of the display elements and that forms a third sacrificial layer over the electrode and the second contact in the switch;

a sixth patterning step that forms a mirror in each of the display elements and that forms the first contact in the switch;

a seventh patterning step that forms a fourth sacrificial layer over at least part of the mirror in each of the display elements and that forms a fourth sacrificial layer over at least part of the first contact in the switch; and

an eighth patterning step that forms a deformable structure over the mirror in each of the display elements and that forms a deformable structure over the first contact in the switch.

6. The method of claim 5, wherein the first patterning step comprises:

depositing a first conductive layer;

forming a first patterned layer covering portions of the first conductive layer;

removing the portions of the first conductive layer not covered by the first patterned layer; and

removing the first patterned layer.

7. The method of claim 6, wherein depositing the first conductive layer comprises depositing a transparent conductive layer.

8. The method of claim 7, wherein the transparent conductive layer comprises indium tin oxide (ITO).

9. The method of claim 7, wherein the transparent conductive layer comprises chromium.

10. The method of claim 5, wherein the second patterning step comprises:

depositing an insulating material;

forming a second patterned layer covering portions of the insulating material;

removing the portions of the insulating material not covered by the second patterned layer; and

removing the second patterned layer.

11. The method of claim 10, wherein depositing the insulating material comprises depositing a transparent oxide layer.

12. The method of claim 10, wherein depositing the insulating material comprises depositing a transparent nitride layer.

13. The method of claim 5, wherein the third patterning step comprises:

depositing a first sacrificial material;

forming a third patterned layer covering portions of the first sacrificial material;

removing the portions of the first sacrificial material not covered by the third patterned layer; and

removing the third patterned layer.

14. The method of claim 5, wherein the fourth patterning step comprises:

depositing a second sacrificial material;

forming a fourth patterned layer covering portions of the second sacrificial material;

removing the portions of the second sacrificial material not covered by the fourth patterned layer; and

removing the fourth patterned layer.

15. The method of claim 5, wherein the fifth patterning step comprises:

depositing a third sacrificial material;

forming a fifth patterned layer covering portions of the third sacrificial material;

removing the portions of the third sacrificial material not covered by the fifth patterned layer; and

removing the fifth patterned layer.

16. The method of claim 5, wherein the sixth patterning step comprises:

depositing a second conductive layer;

forming a sixth patterned layer covering portions of the second conductive layer;

removing the portions of the second conductive layer not covered by the sixth patterned layer; and

removing the sixth patterned layer.

17. The method of claim 16, wherein the second conductive layer comprises aluminum.

18. The method of claim 5, wherein the first contact is in contactless electrical communication with the electrode of the switch.

19. The method of claim 5, wherein the seventh patterning step comprises:

depositing a fourth sacrificial material;

exposing portions of the fourth sacrificial material; and

removing the unexposed portions of the fourth sacrificial material.

20. The method of claim 5, wherein the seventh patterning step comprises:

depositing a fourth sacrificial material;

forming a seventh patterned layer covering portions of the fourth sacrificial material;

removing the portions of the fourth sacrificial material not covered by the seventh patterned layer; and

removing the seventh patterned layer.

21. The method of claim 5, wherein the eighth patterning step comprises:

depositing a deformable layer;

forming an eighth patterned layer covering portions of the fourth sacrificial layer;

removing the portions of the fourth sacrificial layer not covered by the eighth patterned layer; and

removing the eighth patterned layer.

22. The method of claim 21, wherein the deformable layer comprises aluminum.

23. The method of claim 21, wherein the deformable layer comprises nickel.

24. The method of claim 21, wherein depositing the deformable layer comprises fusing the deformable layer to the mirrors in each of the display elements and to the first contact in the switch.

25. The method of claim 5, further comprising removing the first, second, third, and fourth sacrificial layers.

26. The method of claim 25, wherein removing the first, second, third, and fourth sacrificial layers comprises:

removing the fourth sacrificial layer with a first process having a first chemistry; and

removing the first, second, and third sacrificial layers with a second process having a second chemistry different from the first chemistry.

27. The method of claim 26, wherein the first chemistry comprises oxygen and wherein the second chemistry comprises xenon difluoride (XeF₂).

28. The method of claim 5, further comprising:

a ninth patterning step that forms a fifth sacrificial layer over the deformable structure in each of the display elements and that forms a fifth sacrificial layer over the deformable structure in the switch; and

a tenth patterning step that forms a bus layer over the fifth sacrificial layer in each of the display elements and over the fifth sacrificial layer in the switch.

29. The method of claim 28, wherein the ninth patterning step comprises:

depositing a fifth sacrificial material;

forming a ninth patterned layer covering portions of the fifth sacrificial material;

removing the portions of the fifth sacrificial material not covered by the ninth patterned layer; and

removing the ninth patterned layer.

30. The method of claim 29, further comprising depositing a second insulating layer over the fifth sacrificial material.

31. The method of claim 28, wherein the tenth patterning step comprises:

depositing a third conductive layer;

forming a tenth patterned layer covering portions of the third conductive layer;

removing the portions of the third conductive layer not covered by the tenth patterned layer; and

removing the tenth patterned layer

32. The method of claim 28, wherein the tenth patterning step forms a second display element electrode in each display element.

33. The method of claim 28, further comprising removing the fifth sacrificial layer.

34. The method of claim 1, wherein the first set of patterning steps comprises:

a first patterning step that forms an electrode in each of the display elements and that forms the electrode and the second contact in the switch;

a second patterning step that forms an insulating layer over the electrode in each of the display elements and that forms an insulating layer over the electrode in the switch;

a third patterning step that forms a first sacrificial layer over the electrode in each of the display elements and that forms a first sacrificial layer over the electrode and the second contact in the switch; and

a fourth patterning step that forms a mirror in each of the display elements and that forms the first contact in the switch.

35. The method of claim 34, further comprising removing the first sacrificial layer.

36. The method of claim 34, further comprising:

a fifth patterning step that forms a second sacrificial layer over the mirror in each of the display elements and that forms a second sacrificial layer over the first contact in the switch; and

a sixth patterning step that forms a bus layer over the second sacrificial layer in each of the display elements and over the second sacrificial layer in the switch.

37. The method of claim 36, further comprising removing the second sacrificial layer.

38. The method of claim 1, wherein the plurality of display elements in parallel electrical communication with the second contact of the switch comprises between about 1 and 10 display elements.

39. A display device fabricated by the method of claim 1.

40. The display device of claim 39, further comprising:

a processor configured to communicate with the display, the processor configured to process image data; and

a memory device configured to communicate with the processor.

41. The display device of claim 40, further comprising a driver circuit configured to send at least one signal to the display.

42. The display device of claim 41, further comprising a controller configured to send at least a portion of the image data to the driver circuit.

43. The display device of claim 40, further comprising an image source module configured to send the image data to the processor.

44. The display device of claim 43, wherein the image source module comprises at least one of a receiver, transceiver, and transmitter.

45. The display device of claim 40, further comprising an input device configured to receive input data and to communicate the input data to the processor.

46. A method of fabricating a display device, the method comprising:

forming a switch comprising a first electrode, a second electrode, a first contact, and a second contact using a first set of patterning steps, the switch responsive to voltages applied to the first electrode in order to move the first contact into electrical communication with the second contact, the switch further responsive to voltages applied to the second electrode in order to move the first contact and the second contact out of electrical communication, wherein forming the second electrode comprises a third set of patterning steps, the first set of patterning steps comprising the third set of patterning steps; and

forming a plurality of display elements in parallel electrical communication with the switch using a second set of patterning steps, the plurality of display elements comprising a bus structure, wherein forming the bus structure comprises a fourth set of patterning steps, the second set of patterning steps comprising the fourth set of patterning steps, wherein the fourth set of patterning steps comprises the third set of patterning steps.

47. The method of claim 46, wherein the plurality of display elements comprises a plurality of interferometric modulators.

48. The method of claim 46, wherein the second set of patterning steps comprises the first set of patterning steps.

49. The method of claim 46, wherein the first set of patterning steps comprises one or more patterning steps that do not form the display elements.

50. The method of claim 46, wherein the third set of patterning steps comprises:

a first patterning step that forms a sacrificial layer over the display elements and that forms a sacrificial layer over the first contact in the switch; and

a second patterning step that forms the bus structure over the sacrificial layer in the display elements and that forms the second electrode over the sacrificial layer in the switch.

51. A display device fabricated by the method of claim 46.

52. A microelectromechanical (MEMS) switch comprising:

a first electrode;

a second electrode; and

a movable structure between the first electrode and the second electrode and having a first contact, wherein the movable structure is responsive to voltages applied to the first electrode to selectively move such that the first contact is in electrical communication with a second contact and is responsive to voltages applied to the second electrode to selectively move such that the first contact and the second contact are not in electrical communication.