Electrical contacts in microelectromechanical devices with multiple substrates

• US 20050275931A1
• Filed: 04/08/2005
• Published: 12/15/2005
• Est. Priority Date: 06/15/2004
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Tarn, Terry, Richards, Peter, Patel, Satyadev, Doan, Jonathan
• Granted Patent: US 7,110,160 B2
• Time in Patent Office: Days
• US Class Current: 359/291
• CPC Class Codes: B81C 3/001 Bonding of two components
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: Y10S 359/90 Methods
• CPC Class Codes: Y10T 156/10 Methods of surface bonding and/or assembly therefor

Abstract

Disclosed herein a microelectromechanical device having first and second substrates that are bonded together with a gap formed therebetween. A plurality of functional members is disposed within the gap. The two substrates are bonded with a bonding agent that comprises an electrically conductive adhesive material.

Claims

1. A micromirror array device, comprising:

first and second substrates bonded together so as to form a gap therebetween;

an array of deflectable reflective mirror plates disposed within the gap;

a first electrical contact on the first substrate;

a second electrical contact in the second substrate; and

wherein the first and second electrical contacts are electrically contacted within the gap.

2. The device of claim 1, wherein the first and second electrical contacts comprise a conductive adhesive material.

3. The device of claim 2, wherein the first and second substrates are bonded with the conductive adhesive material.

4. The device of claim 2, wherein the conductive adhesive material has a low outgassing.

5. The device of claim 2, wherein the conductive adhesive comprises an electrically conductive epoxy.

6. The device of claim 5, wherein the conductive epoxy comprises an epoxy doped with an electrically conductive material.

7. The device of claim 6, wherein the electrically conductive material is a metal element.

8. The device of claim 6, wherein the metal element is silver.

9. The device of claim 6, wherein the metal element is gold.

10. The device of claim 6, wherein the metal element is carbon.

11. The device of claim 6, wherein the electrically conductive material is a metalloid.

12. The device of claim 6, wherein the electrically conductive material is an intermetallic compound.

13. The device of claim 6, wherein the electrically conductive material is a conductive organic material.

14. The device of claim 6, wherein the electrically conductive material is a conductive polymer.

15. The device of claim 6, wherein the electrically conductive material comprises a carbide of a material that is selected from the group consisting of:

a metal element, a metalloid, an intermetallic compound, and a ceramic.

16. The device of claim 6, wherein the epoxy is an IR curable epoxy.

17. The device of claim 6, wherein the epoxy is an UV curable epoxy.

18. The device of claim 1, wherein the first electric contact is connected to the mirror plates.

19. The device of claim 18, wherein the second substrate comprises a set of electric contacting pads, at least one of which is connected to the second electrical contact such that said at least one of the electric contacting pads is connected to the mirror plates via the first and second electrical contacts.

20. The device of claim 19, wherein the contacting pads on the second substrate are connected to another set of electrical contacting pads on a package substrate having a supporting surface on which the device is disposed.

21. The device of claim 19, wherein the first substrate further comprises a third electrical contacting pad.

22. The device of claim 21, wherein the third electrical contacting pad is connected to an electrode on the first substrate.

23. The device of claim 22, wherein the second substrate further comprises a forth electrical contacting pad disposed at a location such that when the first and second substrates are aligned and bonded together, the third and forth electrical contacts are aligned and connected to each other.

24. The device of claim 1, wherein the first and second substrates are bonded together with a sealing ring disposed around a circumference of the first or second substrate;

and wherein the first and second electrical contacts are enclosed within the sealing ring.

25. The device of claim 1, wherein the first and second electrical contacts on the first and second substrates are located outside an area in which the array of mirror plates are disposed.

26. The device of claim 1, wherein the first substrate is transmissive to the visible light;

and wherein the second substrate is a semiconductor substrate.

27. The device of claim 26, wherein the mirror plates are formed on the light transmissive substrate.

28. The device of claim 27, wherein each mirror plate is associated with one single addressing electrode for being addressed and deflected.

29. The device of claim 27, further comprising:

another electrode on the first substrate for rotating the mirror plate towards the first substrate.

30. The device of claim 27, wherein each mirror plate is attached to a deformable hinge such that the mirror plate is operable to rotate relative to the first substrate.

31. The device of claim 30, wherein the mirror plate and deformable hinge are disposed on separate planes that are spaced apart in a direction perpendicular to the first substrate when the mirror plate is not deflected.

32. The device of claim 30, wherein the mirror plate and deformable hinge are disposed on the same plane.

33. The device of claim 1, wherein the mirror plates are formed on the second substrate one which the addressing electrodes are formed.

34. The device of claim 1, wherein the addressing electrodes are electrically connected to the second electrical contacting pad on the second substrate.

48. The device of claim 3, wherein the first contact on the first substrate is connected to th mirror plates.

35. A microelectromechanical device, comprising:

first and second substrates bonded together so as to form a gap therebetween;

an array of microelements disposed within the gap;

a first electrical contact on the first substrate;

a second electrical contact in the second substrate; and

wherein the first and second electrical contacts are electrically contacted within the gap.

36. The device of claim 35, wherein the microelements are electrostatically deflectable elements.

37. The device of claim 36, wherein the microelements are deflectable reflective mirror plates.

38. The device of claim 37, wherein the mirror plates are formed on the first substrate that is transmissive to visible light.

39. The device of claim 35, wherein the first substrate is bonded to the second substrate via a packaging substrate having a supporting surface on which the second substrate is disposed.

40. The device of claim 39, wherein the mirror plates are formed on the second substrate.

41. The device of claim 39, wherein the mirror plates are derived from a single crystal.

42. The device of claim 35, wherein the first and second contacts are an electrically conductive adhesive.

43. The device of claim 42, wherein the adhesive comprises an epoxy.

44. The device of claim 43, wherein the epoxy is filled with an electrically conductive material.

45. The device of claim 44, wherein the conductive material is selected from the group consisting of:

a metal element, a metalloid, an intermetallic material, an ceramic, organic material and a polymer.

46. The device of claim 44, wherein the conductive material comprises a carbon.

47. The device of claim 44, wherein the conductive material comprises a carbide of a material selected from a group consisting of a metal element, a metalloid, an intermetallic material, an ceramic, organic material and a polymer.

49. A device, comprising:

first and second substrates bonded together so as to form a gap whose boundaries along the normal direction of one of the two substrates are defined by a lower surface of one of the two substrates and an upper surface of the other one of two substrates;

an array of deflectable reflective elements disposed within the gap; and

an electrically conductive adhesive disposed within the gap.

50. A device, comprising:

a first substrate bonded to a semiconductor substrate with a bonding agent that comprises an electrically conductive adhesive so as to form a gap therebetween in the normal direction of the semiconductor substrate; and

a movable microelement within the gap.

51. The device of claim 50, further comprising:

an electrically non-conductive adhesive disposed between the first and second substrates for bonding the first and second substrates.

52. The device of claim 51, wherein the electrically conductive adhesive comprises an epoxy.

53. The device of claim 52, wherein the epoxy is filled with an electrically conductive material.

54. The device of claim 53, wherein the conductive material comprises carbon.

55. The device of claim 53, wherein the conductive material comprises silver.

56. The device of claim 53, wherein the conductive material comprises gold.

57. The device of claim 53, wherein the conductive material comprises a carbide of a material that is a metal, metalloid, intermetallic material, an organic material, or a polymer.

58. The device of claim 53, wherein the conductive material comprises an organic material.