Low-cost circuit board materials and processes for area array electrical interconnections over a large area between a device and the circuit board
View Patent ↗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.
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 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 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 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 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 one conductor selected from a group consisting of aluminum, aluminum-calcium, gold, silver, copper, nickel, titanium, tungsten, platinum, germanium, polyaniline, polyamide, and polysilicon; and
the 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, sliver, 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 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 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 particles within the organic material.
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 coating formed on at least a portion of the front surface of the flexible substrate; and
the thermal conduction 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 coating is formed of at least one of aluminum, aluminum-calcium, gold, silver, copper, nickel, titanium, tungsten, platinum, and 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;
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 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.