Low-cost circuit board materials and processes for area array electrical interconnections over a large area between a device and the circuit board

• US RE41,669 E1
• Filed: 01/26/2007
• Issued: 09/14/2010
• Est. Priority Date: 05/10/2002
• Status: Active Grant

• Current Assignee: Transpacific Infinity LLC
• Original Assignee: Transpacific Infinity LLC
• Inventors: Palanisamy, Ponnusamy
• Primary Examiner(s): Fulk; Steven J
• Application Number:
  US11/699,322
• Time in Patent Office: 1,327 Days
• Field of Search: 361/760, 257/678, 257/700, 257/701, 257/690, 257/707, 257/717, 257/724, 257/778, 438/112, 438/110, 438/121, 438/122, 438/113, 438/612, 345/80, 345/903, 345/76, 313/506, 313/503, 313/498
• US Class Current: 257/678
• CPC Class Codes: G02F 1/133382 Heating or cooling of liquid crystal cells other than for activation, e.g. circuits or arrangements for temperature control, stabilisation or uniform distribution over the cell
• CPC Class Codes: G02F 1/13452 Conductors connecting driver circuitry and terminals of panels
• CPC Class Codes: H01L 2251/5338 Flexible OLED
• CPC Class Codes: H01L 27/3288 Wiring lines
• CPC Class Codes: H01L 27/3293 Tiled displays
• CPC Class Codes: H01L 51/524 Sealing arrangements having a self-supporting structure, e.g. containers
• CPC Class Codes: H01L 51/529 Arrangements for heating or cooling
• CPC Class Codes: H05K 1/0203 Cooling of mounted components H05K1/0272 takes precedence
• CPC Class Codes: H05K 1/147 at least one of the printed circuits being bent or folded, e.g. by using a flexible printed circuit H05K1/148 takes precedence
• CPC Class Codes: H05K 1/189 characterised by the use of a flexible or folded printed circuit H05K3/326 takes precedence
• CPC Class Codes: H05K 3/321 by conductive adhesives
• CPC Class Codes: H05K 3/3436 having an array of bottom contacts, e.g. pad grid array or ball grid array components
• CPC Class Codes: H05K 3/363 by soldering
• CPC Class Codes: Y10T 29/49144 by metal fusion
• CPC Class Codes: Y10T 29/49151 by deforming or shaping
• CPC Class Codes: Y10T 29/49155 Manufacturing circuit on or in base

Abstract

An electronic device and coupled flexible circuit board and method of manufacturing. The electronic device is coupled to the flexible circuit board by a plurality of Z-interconnections. The electronic device includes a substrate with electronic components coupled to it. The substrate also has a plurality of device electrical contacts coupled to its back surface that are electrically coupled to the electronic components. The flexible circuit board includes a flexible substrate having a front surface and a back surface and a plurality of circuit board electrical contacts coupled to the front surface of the flexible substrate. The plurality of circuit board electrical contacts correspond to plurality of device electrical contacts. Each Z-interconnection is electrically and mechanically coupled to one device electrical contact and a corresponding circuit board electrical contact.

Claims

1. An electronic device and coupled flexible circuit board comprising:

the electronic device, including;

a substrate having a back surface;

a plurality of electronic components coupled to the substrate; and

a plurality of device electrical contacts coupled to the back surface of the substrate and electrically coupled to the plurality of electronic components;

the flexible circuit board including;

a flexible substrate having a front surface and a back surface;

and

a plurality of circuit board electrical contacts coupled to the front surface of the flexible substrate corresponding to plurality of device electrical contacts;

a plurality of Z-interconnections, each Z-interconnection electrically and mechanically coupling one device electrical contact to a corresponding circuit board electrical contact; and

a fill layer mechanically coupling a portion of the back surface of the electronic device to a corresponding portion of the front surface of the flexible substrate.

2. The electronic device end and coupled flexible circuit board of claim 1, wherein the plurality of electronic components of the electronic device are sized and arranged to form a matrix array of electronic components.

3. The electronic device and coupled flexible circuit board of claim 1, wherein the plurality of electronic components of the electronic device are at least one of liquid crystal devices, light emitting diodes, organic light emitting diodes, and or optical detectors.

4. The electronic device and coupled flexible circuit board of claim 1, wherein a substrate material of the substrate of the electronic device includes at least one of glass, alumina, epoxy resin, fiberglass, polyester, and or polyimide.

5. The electronic device and coupled flexible circuit board of claim 1, wherein a flexible substrate material of the flexible substrate of the flexible circuit board includes at least one of polyester and or polyimide.

6. The electronic device and coupled flexible circuit board of claim 1, wherein;

;

the plurality of device electrical contacts formed on the back surface of the substrate are formed of at east least one conductor selected from a group consisting of aluminum, aluminium-calcium, gold, silver, copper, nickel, titanium, tungsten, platinum, germanium, polyaniline, polyamide, and polysilicon; and

thean electrical trace and the plurality of circuit board electrical contacts formed on the front surface of the flexible substrate are formed of at least one conductor selected from a group consisting of aluminum, aluminum-calcium, gold, sliversilver, copper, nickel, titanium, tungsten, platinum, germanium, polyaniline, polyamide, and polysilicon.

7. The electronic device and coupled flexible circuit board of claim 1, wherein the plurality of Z-interconnections are formed of at least one conductor selected from a group consisting of indium, a conductive solder, a conductive thermally-curable epoxy, a conductive radiation-curable epoxy, a conductive thermoplastic, and a conductive elastomer.

8. The electronic device and coupled flexible circuit board of claim 1, further comprising:

a rigid substrate laminated to the flexible circuit board;

wherein the substrate of the electronic device has a first thermal expansion coefficient and the rigid substrate has second thermal expansion coefficient, which is approximately equal to the first thermal expansion coefficient.

9. The electronic device and coupled flexible circuit board of claim 1, wherein the back surface of the substrate of the electronic device is non-planar.

10. The electronic device and coupled flexible circuit board of claim 1, wherein:

a connection portion of the front surface of the flexible substrate of the flexible circuit board extends past an edge of the back surface of the substrate of the electronic device; and

a connector portion the of an electrical trace is formed on the connection portion of the front surface of the flexible substrate.

11. The electronic device and coupled flexible circuit board of claim 1, wherein the flexible circuit board further includes:

a backside electrical trace formed on the back surface of the flexible substrate, the backside electrical trace electrically coupled to at least one of plurality of electrical contacts formed on the front surface of the flexible substrate; and

at least one circuit board electronic component coupled to the back surface of the flexible substrate and electrically coupled to the backside electrical trace.

12. The electronic device and coupled flexible circuit board of claim 1, wherein the fill layer is formed of an organic material including at least one of a non-conductive epoxy, a non-conductive thermoplastic, and or a non-conductive elastomer.

13. The electronic device and coupled flexible circuit board of claim 12, wherein the fill layer further includes a plurality of thermally conductive, non-electrically conductive particles within the organic material.

20. The electronic device and coupled flexible circuit board of claim 1, wherein the flexible circuit board is substantially spherically concave, substantially spherically convex, or bent at an angle.

14. An electronic device and coupled flexible circuit board comprising:

the electronic device including;

a substrate having a back surface;

a plurality of electronic components coupled to the substrate; and

a plurality of device electrical contacts coupled to the back surface of the substrate and electrically coupled to the plurality of electronic components;

the flexible circuit board including;

a flexible substrate having a front surface and a back surface;

and

a plurality of circuit board electrical contacts coupled to the front surface of the flexible substrate corresponding to plurality of device electrical contacts;

a plurality of Z-interconnections, each Z-interconnection electrically and mechanically coupling one device electrical contact to a corresponding circuit board electrical contact;

wherein the flexible substrate of the flexible circuit board includes an elevated portion which extends away from the back surface of the substrate of the electronic device, and none of the plurality of circuit board electrical contacts is formed on the elevated portion of the flexible substrate of the flexible circuit board.

15. The electronic device and coupled flexible circuit board of claim 14, wherein the flexible circuit board further includes a circuit board electronic component coupled to the elevated portion of the flexible substrate and electrically coupled to at least one of the plurality of electrical contacts formed on the front surface of the flexible substrate.

16. An electronic device and coupled flexible circuit board comprising:

the electronic device including;

a substrate having a back surface;

a plurality of electronic components coupled to the substrate; and

a plurality of device electrical contacts coupled to the back surface of the substrate and electrically coupled to the plurality of electronic components;

the flexible circuit board including;

a flexible substrate having a front surface and a back surface;

and

a plurality of circuit board electrical contacts coupled to the front surface of the flexible substrate corresponding to plurality of device electrical contacts;

a plurality of Z-interconnections, each Z-interconnection electrically and mechanically coupling one device electrical contact to a corresponding circuit board electrical contact;

wherein;

the flexible circuit board further includes a thermal conduction thermally conductive coating formed on at least a portion of the front surface of the flexible substrate; and

the thermal conduction thermally conductive coating is not electrically coupled to the plurality of electrical contacts formed on the front surface of the flexible substrate.

17. The electronic device and coupled flexible circuit board of claim 16, wherein the thermal conduction thermally conductive coating is formed of at least one of aluminum, aluminum-calcium, gold, silver, copper, nickel, titanium, tungsten, platinum, and or germanium.

18. An electronic device and coupled flexible circuit board comprising:

the electronic device, including;

a substrate having a back surface;

a plurality of electronic components coupled to the substrate;

and

a plurality of device electrical contacts coupled to the back surface of the substrate and electrically coupled to the plurality of electronic components;

the flexible circuit board including;

a flexible substrate having a front surface and a back surface; and

a plurality of circuit board electrical contacts coupled to the front surface of the flexible substrate corresponding to plurality of device electrical contacts;

and

a plurality of Z-interconnections, each Z-interconnection electrically and mechanically coupling one device electrical contact to a corresponding circuit board electrical contact;

wherein the flexible circuit board further includes a thermal conduction thermally conductive coating formed on at least a portion of the back surface of the flexible substrate.

19. An electronic device and coupled flexible circuit board comprising:

the electronic device including;

a substrate having a back surface;

a plurality of electronic components coupled to the substrate; and

a plurality of device electrical contacts coupled to the back surface of the substrate and electrically coupled to the plurality of electronic components;

the flexible circuit board including;

a flexible substrate having a front surface and a back surface; and

a plurality of circuit board electrical contacts coupled to the front surface of the flexible substrate corresponding to plurality of device electrical contacts;

a plurality of Z-interconnections, each Z-interconnection electrically and mechanically coupling one device electrical contact to a corresponding circuit board electrical contact;

wherein the flexible circuit board further includes a heat sink coupled to the back surface of the flexible substrate.

21. An apparatus, comprising:

a first substrate having a front surface and a back surface;

a plurality of electrical contacts coupled to the front surface of the first substrate and corresponding to a plurality of device electrical contacts coupled to an electronic device;

a plurality of Z-interconnections, wherein the individual Z-interconnections are configured to couple an electrical contact to a corresponding device electrical contact coupled to the electronic device; and

a fill layer configured to couple the front surface of the first substrate to a corresponding portion of a back surface of the electronic device, wherein the fill layer comprises a plurality of thermally conductive, non-electrically conductive particles within an organic material.

22. The apparatus of claim 21, wherein the first substrate comprises a flexible substrate.

23. The apparatus of claim 21, wherein the plurality of electrical contacts are formed of at least one conductor selected from the group consisting of aluminum, aluminum-calcium, gold, silver, copper, nickel, titanium, tungsten, platinum, germanium, polyaniline, polyamide, and polysilicon.

24. The apparatus of claim 21, wherein the plurality of Z-interconnections are formed of at least one conductor selected from a group consisting of indium, a conductive solder, a conductive thermally-curable epoxy, a conductive radiation-curable epoxy, a conductive thermoplastic, and a conductive elastomer.

25. The apparatus of claim 21, wherein the electronic device comprises:

a second substrate; and

a plurality of electronic components coupled both to the second substrate and to the plurality of device electrical contacts, wherein the plurality of device electrical contacts are coupled to the back surface of the second substrate.

26. The apparatus of claim 25, wherein the plurality of electronic components are sized and arranged to form a matrix.

27. The apparatus of claim 25, wherein the plurality of electronic components comprises at least one liquid crystal devices, light emitting diodes, organic light emitting diodes, or optical detectors.

28. The apparatus of claim 25, wherein the second substrate comprises at least one of glass, alumina, epoxy resin, fiberglass, polyester, or polyimide.

29. The apparatus of claim 25, wherein the plurality of device electrical contacts are formed of at least one conductor selected from a group consisting of aluminum, aluminum-calcium, gold, silver, copper, nickel, titanium, tungsten, platinum, germanium, polyaniline, polyamide, and polysilicon.

30. The apparatus of claim 24, wherein:

the first substrate is a flexible substrate;

the apparatus further comprises a rigid substrate coupled to the flexible substrate;

wherein the second substrate has a first thermal expansion coefficient; and

the rigid substrate has a second thermal expansion coefficient approximately equal to the first thermal expansion coefficient.

31. The apparatus of claim 25, wherein:

the first substrate is a flexible substrate; and

the back surface of the second substrate is non-planar.

32. The apparatus of claim 25, wherein:

a connection portion of the front surface of the first substrate extends past an edge of the back surface of the second substrate; and

a connector portion of an electrical trace is formed on the connection portion of the front surface of the first substrate.

33. The apparatus of claim 25, further comprising:

a backside electrical trace formed on the back surface of the first substrate, wherein the backside electrical trace electrically couples to at least one of the plurality of electrical contacts formed on the front surface of the first substrate; and

at least one electronic component coupled to the back surface of the first substrate and electrically coupled to the backside electrical trace.

34. The apparatus of claim 21, wherein the fill layer is formed of an organic material comprising at least one of a non-conductive epoxy, a non-conductive thermoplastic, or a non-conductive elastomer.

35. The apparatus of claim 21, wherein the Z-interconnections comprise a plurality of electrically conductive particles within an organic material.

36. The apparatus of claim 35, wherein the organic material in the fill layer and the organic material in the Z-interconnections are the same material.

37. An apparatus, comprising:

a flexible substrate having a front surface and a back surface;

a plurality of electrical contacts coupled to the front surface of the flexible substrate and corresponding to a plurality of device electrical contacts coupled to a device substrate of an electronic device; and

a plurality of Z-interconnections, wherein the individual Z-interconnections are configured to couple an electrical contact to a corresponding device electrical contact in the electronic device, wherein the flexible substrate comprises an elevated portion extending away from a back surface of the device substrate and none of the plurality of electrical contacts is formed on the elevated portion of the flexible substrate.

38. The apparatus of claim 37, further comprising an electronic component coupled to the elevated portion of the flexible substrate and electrically coupled to at least one of the plurality of electrical contacts formed on the front surface of the flexible substrate.

39. The apparatus of claim 37, wherein the electronic device further comprises a plurality of electronic components coupled to a front surface of the device substrate and coupled to the plurality of device electrical contacts, and wherein the plurality of device electrical contacts are coupled to a back surface of the device substrate.

40. The apparatus of claim 39, wherein the plurality of electronic components comprises at least one of liquid crystal devices, light emitting diodes, organic light emitting diodes, or optical detectors.

41. An apparatus comprising:

a first substrate having a front surface and a back surface;

a thermally conductive coating formed on at least a portion of the first substrate and configured for lateral heat diffusion;

a plurality of electrical contacts coupled to the front surface of the first substrate and corresponding to a plurality of device electrical contacts coupled to an electronic device; and

a plurality of Z-interconnections, wherein the individual Z-interconnections are configured to couple an electrical contact to a corresponding device electrical contact of the electronic device.

42. The apparatus of claim 41, wherein the thermally conductive coating is formed on at least a portion of the front surface of the first substrate, and wherein the thermally conductive coating is not electrically coupled to the plurality of electrical contacts coupled to the front surface of the first substrate.

43. The apparatus of claim 41, wherein the thermally conductive coating is formed on at least a portion of the back surface of the first substrate.

44. The apparatus of claim 41, wherein the thermally conductive coating is formed of at least one aluminum, aluminum-calcium, gold, silver, copper, nickel, titanium, tungsten, platinum, or germanium.

45. The apparatus of claim 41, wherein the electronic device comprises:

a second substrate; and

a plurality of electronic components coupled both to a front surface of the second substrate and to the plurality of device electrical contacts, wherein the plurality of device electrical contacts is coupled to a back surface of the second substrate.

46. The apparatus of claim 45, wherein the plurality of electronic components comprises at least one of liquid crystal devices, light emitting diodes, organic light emitting diodes, or optical detectors.

47. An electronic device, comprising:

a substrate having a surface;

a plurality of electrical contacts coupled to the surface of the substrate;

a plurality of Z-interconnections coupled to the electrical contacts; and

a thermally conductive, non-electrically conductive fill layer around the Z-interconnections;

wherein the fill layer comprises thermally conductive, non-electrically conductive particles in an organic matrix and the Z-interconnections comprise electrically conductive particles in an organic matrix.

48. The electronic device of claim 47, wherein the organic matrix of the fill layer and the organic matrix of the Z-interconnections comprise the same organic material.