Electronic devices with yielding substrates

• US 8,907,370 B2
• Filed: 01/31/2014
• Issued: 12/09/2014
• Est. Priority Date: 06/29/2010
• Status: Expired due to Fees

• Current Assignee: Cooledge Lighting Inc.
• Original Assignee: Cooledge Lighting Inc.
• Inventors: Tischler, Michael A., Schick, Philippe M., Ashdown, Ian, Sheen, Calvin Wade, Jungwirth, Paul
• Primary Examiner(s): Lee, Calvin
• Application Number:
  US14/169,384
• Publication Number:
  US 20140191257A1
• Time in Patent Office: 312 Days
• Field of Search: 438 22- 26, 257/81, 257/99
• US Class Current: 257/99
• CPC Class Codes: F21K 9/20 Light sources comprising attachment means
• CPC Class Codes: F21K 9/275 Details of bases or housings, i.e. the parts between the light-generating element and the end caps; Arrangement of components within bases or housings F21K9/278 takes precedence
• CPC Class Codes: F21K 9/278 Arrangement or mounting of circuit elements integrated in the light source
• CPC Class Codes: F21K 9/64 using wavelength conversion means distinct or spaced from the light-generating element, e.g. a remote phosphor layer
• CPC Class Codes: F21K 9/65 specially adapted for changing the characteristics or the distribution of the light, e.g. by adjustment of parts
• CPC Class Codes: F21K 9/66 Details of globes or covers forming part of the light source
• CPC Class Codes: F21V 13/08 the elements being filters or photoluminescent elements and reflectors
• CPC Class Codes: F21V 13/14 the elements being filters or photoluminescent elements, reflectors and refractors
• CPC Class Codes: F21V 23/003 the elements being electronics drivers or controllers for operating the light source, e.g. for a LED array
• CPC Class Codes: F21V 23/02 the elements being transformers, impedances or power supply units, e.g. a transformer with a rectifier
• CPC Class Codes: F21V 29/74 with fins or blades
• CPC Class Codes: F21V 3/02 characterised by the shape
• CPC Class Codes: F21V 5/10 comprising photoluminescent material
• CPC Class Codes: F21V 7/30 the coatings comprising photoluminescent substances
• CPC Class Codes: F21V 9/30 Elements containing photoluminescent material distinct from or spaced from the light source shades F21V1/17; globes, bowls or cover glasses F21V3/08, F21V3/12; refractors F21V5/10; reflectors F21V7/26, F21V7/30; elements with provision for controlling the spectral properties or intensity F21V9/40
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: H01L 2224/06102 the bonding areas being at different heights
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/2929 with a principal constituent of the material being a polymer, e.g. polyester, phenolic based polymer, epoxy
• CPC Class Codes: H01L 2224/32225 : the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/73204 : the bump connector being embedded into the layer connector
• CPC Class Codes: H01L 2224/83385 : Shape, e.g. interlocking features
• CPC Class Codes: H01L 2224/83851 : being an anisotropic conductive adhesive
• CPC Class Codes: H01L 2224/83862 : Heat curing
• CPC Class Codes: H01L 2225/107 : Indirect electrical connections, e.g. via an interposer, a flexible substrate, using TAB printed circuits H05K1/00
• CPC Class Codes: H01L 23/367 : Cooling facilitated by shape of device H01L23/38, H01L23/40, H01L23/42, H01L23/44, H01L23/46 take precedence
• CPC Class Codes: H01L 23/4985 : Flexible insulating substrates H01L23/49572 and H01L23/49855 take precedence
• CPC Class Codes: H01L 23/5387 : Flexible insulating substrates H01L23/5388 takes precedence
• CPC Class Codes: H01L 24/32 : of an individual layer connector
• CPC Class Codes: H01L 24/83 : using a layer connector
• CPC Class Codes: H01L 25/0753 : the devices being arranged next to each other
• CPC Class Codes: H01L 27/156 : two-dimensional arrays
• CPC Class Codes: H01L 2924/00 : Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00014 : the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/01005 : Boron [B]
• CPC Class Codes: H01L 2924/01006 : Carbon [C]
• CPC Class Codes: H01L 2924/01013 : Aluminum [Al]
• CPC Class Codes: H01L 2924/01015 : Phosphorus [P]
• CPC Class Codes: H01L 2924/01019 : Potassium [K]
• CPC Class Codes: H01L 2924/0102 : Calcium [Ca]
• CPC Class Codes: H01L 2924/01023 : Vanadium [V]
• CPC Class Codes: H01L 2924/01024 : Chromium [Cr]
• CPC Class Codes: H01L 2924/01029 : Copper [Cu]
• CPC Class Codes: H01L 2924/0103 : Zinc [Zn]
• CPC Class Codes: H01L 2924/01031 : Gallium [Ga]
• CPC Class Codes: H01L 2924/01033 : Arsenic [As]
• CPC Class Codes: H01L 2924/01047 : Silver [Ag]
• CPC Class Codes: H01L 2924/01049 : Indium [In]
• CPC Class Codes: H01L 2924/0105 : Tin [Sn]
• CPC Class Codes: H01L 2924/01051 : Antimony [Sb]
• CPC Class Codes: H01L 2924/01058 : Cerium [Ce]
• CPC Class Codes: H01L 2924/01063 : Europium [Eu]
• CPC Class Codes: H01L 2924/01073 : Tantalum [Ta]
• CPC Class Codes: H01L 2924/01074 : Tungsten [W]
• CPC Class Codes: H01L 2924/01075 : Rhenium [Re]
• CPC Class Codes: H01L 2924/01078 : Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/01082 : Lead [Pb]
• CPC Class Codes: H01L 2924/0132 : Binary Alloys
• CPC Class Codes: H01L 2924/014 : Solder alloys
• CPC Class Codes: H01L 2924/07802 : not being an ohmic electrical conductor
• CPC Class Codes: H01L 2924/07811 : Extrinsic, i.e. with electrical conductive fillers
• CPC Class Codes: H01L 2924/10253 : Silicon [Si]
• CPC Class Codes: H01L 2924/10321 : Aluminium antimonide [AlSb]
• CPC Class Codes: H01L 2924/10322 : Aluminium arsenide [AlAs]
• CPC Class Codes: H01L 2924/10323 : Aluminium nitride [AlN]
• CPC Class Codes: H01L 2924/10324 : Aluminium phosphide [AlP]
• CPC Class Codes: H01L 2924/10328 : Gallium antimonide [GaSb]
• CPC Class Codes: H01L 2924/10329 : Gallium arsenide [GaAs]
• CPC Class Codes: H01L 2924/1033 : Gallium nitride [GaN]
• CPC Class Codes: H01L 2924/10331 : Gallium phosphide [GaP]
• CPC Class Codes: H01L 2924/10332 : Indium antimonide [InSb]
• CPC Class Codes: H01L 2924/10333 : Indium arsenide [InAs]
• CPC Class Codes: H01L 2924/10334 : Indium nitride [InN]
• CPC Class Codes: H01L 2924/10335 : Indium phosphide [InP]
• CPC Class Codes: H01L 2924/12041 : LED
• CPC Class Codes: H01L 2924/12042 : LASER
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/15787 : Ceramics, e.g. crystalline carbides, nitrides or oxides
• CPC Class Codes: H01L 2924/3512 : Cracking
• CPC Class Codes: H01L 2924/381 : Pitch distance
• CPC Class Codes: H01L 31/0468 : comprising specific means for obtaining partial light transmission through the module, e.g. partially transparent thin film solar modules for windows
• CPC Class Codes: H01L 33/0025 : comprising only AIIIBV compounds
• CPC Class Codes: H01L 33/06 : within the light emitting region, e.g. quantum confinement structure or tunnel barrier
• CPC Class Codes: H01L 33/08 : with a plurality of light emitting regions, e.g. laterally discontinuous light emitting layer or photoluminescent region integrated within the semiconductor body H01L27/15 takes precedence
• CPC Class Codes: H01L 33/28 : containing only elements of Group II and Group VI of the Periodic Table
• CPC Class Codes: H01L 33/30 : containing only elements of Group III and Group V of the Periodic Table
• CPC Class Codes: H01L 33/32 : containing nitrogen
• CPC Class Codes: H01L 33/36 : characterised by the electrodes
• CPC Class Codes: H01L 33/483 : Containers
• CPC Class Codes: H01L 33/486 : adapted for surface mounting
• CPC Class Codes: H01L 33/502 : Wavelength conversion materials
• CPC Class Codes: H01L 33/505 : characterised by the shape, e.g. plate or foil
• CPC Class Codes: H01L 33/58 : Optical field-shaping elements
• CPC Class Codes: H01L 33/60 : Reflective elements
• CPC Class Codes: H01L 33/62 : Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls
• CPC Class Codes: H02S 30/00 : Structural details of PV modules other than those related to light conversion semiconductor device aspects of modules of electrolytic light sensitive devices H01G9/20, of inorganic PV modules H01L31/00, of organic PV modules H10K30/00
• CPC Class Codes: H05B 45/12 : using optical feedback
• CPC Class Codes: H05B 45/22 : using optical feedback
• CPC Class Codes: H05B 47/11 : by determining the brightness or colour temperature of ambient light
• CPC Class Codes: H05B 47/115 : by determining the presence or movement of objects or living beings
• CPC Class Codes: H05B 47/175 : by remote control
• 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 2201/09036 : Recesses or grooves in insulating substrate recess in metallic substrate H05K2201/09745
• CPC Class Codes: H05K 2201/10106 : Light emitting diode [LED]
• CPC Class Codes: H05K 2203/302 : Bending a rigid substrate; Breaking rigid substrates by bending rigid circuit boards or rigid supports locally made bendable H05K1/0278
• CPC Class Codes: H05K 3/323 : by applying an anisotropic conductive adhesive layer over an array of pads
• CPC Class Codes: H10K 77/111 : Flexible substrates
• CPC Class Codes: Y02B 20/40 : Control techniques providing energy savings, e.g. smart controller or presence detection
• CPC Class Codes: Y02E 10/549 : Organic PV cells
• CPC Class Codes: Y02P 70/50 : Manufacturing or production processes characterised by the final manufactured product

Abstract

In accordance with certain embodiments, a semiconductor die is adhered directly to a yielding substrate with a pressure-activated adhesive notwithstanding any nonplanarity of the surface of the semiconductor die or non-coplanarity of the semiconductor die contacts.

Claims

1. An electronic device comprising:

an inorganic light-emitting diode (LED) having first and second spaced-apart contacts;

a flexible substrate having first and second conductive traces on a first surface thereof in a bonding region, the first and second conductive traces being separated on the substrate by a gap therebetween; and

disposed on the substrate, a control circuit electrically connected to the LED,

wherein (i) the first and second conductive traces comprise at least one of silver, gold, aluminum, chromium, copper, or carbon, (ii) the first and second contacts are adhered to and in electrical contact with, respectively, the first and second conductive traces via an anisotropic conductive adhesive (ACA) electrically connecting the first contact only to the first trace and the second contact only to the second trace, and (iii) a portion of the ACA is disposed in the gap and substantially isolates the first contact from the second contact.

2. The device of claim 1, wherein the LED extends across the gap between the first and second traces, and further comprising a second inorganic LED, proximate the LED, extending across the gap between the first and second traces.

3. The device of claim 1, wherein the first and second traces consist essentially of aluminum.

4. The device of claim 1, wherein a reflectivity of the substrate for a wavelength of light emitted by the LED is greater than 80%.

5. The device of claim 1, wherein the LED emits white light having a color temperature in the range of 2000K to 7000K.

6. The device of claim 1, wherein the LED is a packaged LED.

7. The device of claim 1, wherein the LED is a bare LED die.

8. The device of claim 1, further comprising a power supply electrically connected to the LED.

9. The device of claim 1, wherein the substrate comprises a local flexing or a local deformation for maintaining electrical contact between the contacts and traces during operation of the LED.

10. The device of claim 1, wherein the first and second spaced-apart contacts are disposed on a first surface of the LED, and further comprising a reflective material over at least a portion of the first surface of the LED.

11. The device of claim 1, wherein the first and second spaced-apart contacts are substantially coplanar.

12. The device of claim 1, wherein the first and second spaced-apart contacts are disposed on a first surface of the LED, and an offset between the first and second spaced-apart contacts along a dimension substantially perpendicular to the first surface of the LED is at least 0.25 μ

m.

13. The device of claim 1, wherein the gap between the first and second traces ranges between approximately 25 μ

m and approximately 1000 μ

m.

14. The device of claim 1, wherein there is no heat sink in thermal communication with the LED.

15. The device of claim 1, wherein a transmittance of the substrate for a wavelength of light emitted by the LED is greater than 80%.

16. The device of claim 1, wherein a thickness of the first trace and a thickness of the second trace are substantially uniform and substantially equal to each other.

17. The device of claim 1, wherein a junction temperature of the LED does not exceed 100°

C. during operation.

18. The device of claim 1, wherein (i) the LED comprises a p-n junction and (ii) a thermal resistance from the p-n junction to ambient through the substrate is at least 500°

C./W.

19. The device of claim 1, wherein (i) the LED comprises a p-n junction and (ii) a thermal resistance from the p-n junction to ambient through the substrate is at least 1000°

C./W.

20. The device of claim 1, further comprising:

a plurality of additional inorganic LEDs each having first and second spaced-apart contacts, the inorganic LED and the additional inorganic LEDs being arranged in a two-dimensional array on the substrate,

wherein a heat density generated by the two-dimensional array during operation is less than approximately 0.01 W/cm².

21. The device of claim 1, wherein the ACA is a pressure-activated ACA.

22. The device of claim 1, wherein the first and second conductive traces comprise a conductive ink.

23. The device of claim 1, wherein, at least in the bonding region, a height of the first and second traces above the first surface of the substrate does not exceed 10 μ

m.

24. The device of claim 1, wherein the substrate is flexible and deformable.

25. The device of claim 1, wherein (i) the LED comprises a quantum well, and (ii) a distance between the quantum well and the first surface of the substrate is less than 100 μ

m.

26. The device of claim 1, wherein the substrate comprises at least one of polyethylene naphthalate, polyethylene terephthalate, polycarbonate, polyethersulfone, polyester, polyimide, polyethylene, or paper.

27. The device of claim 26, wherein the substrate consists essentially of polyethylene terephthalate.

28. The device of claim 1, further comprising an optical element arranged to transmit light emitted by the LED.

29. The device of claim 11, wherein the optical element is disposed above and optically coupled to the LED.

30. The device of claim 29, wherein the optical element is disposed in contact with at least one of the substrate or the traces so as to enclose the LED between the substrate and the optical element.

31. The device of claim 29, further comprising:

a plurality of additional inorganic LEDs each having first and second spaced-apart contacts, the LED and the additional LEDs being arranged in a two-dimensional array on the substrate; and

a plurality of additional optical elements each disposed over and optically coupled to one of the additional LEDs,

wherein (i) the optical element is optically coupled only to the LED, and (ii) each additional optical element is optically coupled only to a different one of the additional LEDs.

32. The device of claim 1, further comprising, disposed over and at least partially surrounding the LED, a phosphor material for converting at least a portion of light emitted by the LED to a different wavelength.

33. The device of claim 32, further comprising, disposed over the LED, a reflective surface for reflecting converted light toward the flexible substrate.

34. The device of claim 32, further comprising an optically transparent material disposed between the LED and the phosphor material.