Light-emitting dies incorporating wavelength-conversion materials and related methods

• US 8,907,362 B2
• Filed: 07/24/2013
• Issued: 12/09/2014
• Est. Priority Date: 01/24/2012
• Status: Active Grant

• Current Assignee: Epistar Corporation (Ennostar, Inc.)
• Original Assignee: Cooledge Lighting Inc.
• Inventors: Tischler, Michael A.
• Primary Examiner(s): GREEN, TELLY D
• Application Number:
  US13/949,543
• Publication Number:
  US 20140319560A1
• Time in Patent Office: 503 Days
• Field of Search: 257/98, 257/89, 438/27, 438/29, 438/25, 438/28, 438/31, 313/503, 313/501, 313/512, 362/231, 362/97, 362/237, 362/606
• US Class Current: 257/98
• CPC Class Codes: H01L 2224/04105 Bonding areas formed on an encapsulation of the semiconductor or solid-state body, e.g. bonding areas on chip-scale packages
• CPC Class Codes: H01L 2224/1403 Bump connectors having different sizes, e.g. different diameters, heights or widths
• CPC Class Codes: H01L 2224/73204 the bump connector being embedded into the layer connector
• CPC Class Codes: H01L 24/96 the devices being encapsulated in a common layer, e.g. neo-wafer or pseudo-wafer, said common layer being separable into individual assemblies after connecting
• CPC Class Codes: H01L 24/97 the devices being connected to a common substrate, e.g. interposer, said common substrate being separable into individual assemblies after connecting
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• 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 2924/07802 not being an ohmic electrical conductor
• CPC Class Codes: H01L 2924/07811 Extrinsic, i.e. with electrical conductive fillers
• CPC Class Codes: H01L 2924/12032 Schottky diode
• CPC Class Codes: H01L 2924/12041 LED
• CPC Class Codes: H01L 2924/12042 LASER
• CPC Class Codes: H01L 2924/12043 Photo diode
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H01L 2924/1815 Shape
• CPC Class Codes: H01L 2924/18161 of a flip chip
• CPC Class Codes: H01L 2933/0033 relating to semiconductor body packages
• CPC Class Codes: H01L 2933/0083 Periodic patterns for optical field-shaping in or on the semiconductor body or semiconductor body package, e.g. photonic bandgap structures
• CPC Class Codes: H01L 31/055 where light is absorbed and re-emitted at a different wavelength by the optical element directly associated or integrated with the PV cell, e.g. by using luminescent material, fluorescent concentrators or up-conversion arrangements
• 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 33/54 : having a particular shape
• CPC Class Codes: H01L 33/56 : Materials, e.g. epoxy or silicone resin
• 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: Y02E 10/52 : PV systems with concentrators

Abstract

In accordance with certain embodiments, semiconductor dies are embedded within polymeric binder to form, e.g., freestanding white light-emitting dies and/or composite wafers containing multiple light-emitting dies embedded in a single volume of binder.

Claims

1. An electronic device comprising:

a solid shaped volume of a polymeric binder;

suspended within the polymeric binder, a semiconductor die having a first face, a second face opposite the first face, and at least one sidewall spanning the first and second faces, the semiconductor die being a bare-die light-emitting element comprising a plurality of active semiconductor layers that cooperatively emit light, wherein (i) at least a portion of the polymeric binder is transparent to a wavelength of light emitted by the bare-die light-emitting element, and (ii) the polymeric binder contains therein a wavelength-conversion material for absorption of at least a portion of light emitted from the bare-die light-emitting element and emission of converted light having a different wavelength, converted light and unconverted light emitted by the bare-die light-emitting element combining to form mixed light;

disposed on the first face of the semiconductor die, at least two spaced-apart contacts each having a terminal end not covered by the polymeric binder, the contacts each contacting a different active semiconductor layer of the semiconductor die;

a first electrically conductive reflecting layer (i) having a reflectivity of at least 50% to light emitted by at least one of the bare-die light-emitting element or the wavelength-conversion material, (ii) disposed over a portion of a first face of the polymeric binder, (iii) disposed over a portion of the first face of the semiconductor die, and (iv) disposed over and electrically coupled to a first one of the at least two contacts; and

a second electrically conductive reflecting layer (i) having a reflectivity of at least 50% to light emitted by at least one of the bare-die light-emitting element or the wavelength-conversion material, (ii) disposed over a portion of the first face of the polymeric binder, (iii) disposed over a portion of the first face of the semiconductor die, (iv) disposed over and electrically coupled to a second one of the at least two contacts different from the first contact, and (v) electrically insulated from the first reflecting layer.

2. The electronic device of claim 1, wherein the first and second reflecting layers are separated by a gap therebetween.

3. The electronic device of claim 1, wherein the reflectivity, to light emitted by at least one of the bare-die light-emitting element or the wavelength conversion material, of the first and second reflecting layers is at least 75%.

4. The electronic device of claim 1, wherein the reflectivity, to light emitted by at least one of the bare-die light-emitting element or the wavelength conversion material, of the first and second reflecting layers is at least 90%.

5. The electronic device of claim 1, wherein a thickness of the semiconductor die between the first and second faces is (i) greater than a thickness of the first reflecting layer and (ii) greater than a thickness of the second reflecting layer.

6. The electronic device of claim 1, wherein each of the first and second reflecting layers comprises at least one of Cr, Al, Au, Ag, Cu, Ti, silver ink, carbon ink, or copper ink.

7. The electronic device of claim 1, further comprising:

suspended within the polymeric binder, a second semiconductor die having a first face, a second face opposite the first face, and at least one sidewall spanning the first and second faces;

disposed on the first face of the second semiconductor die, at least two spaced-apart contacts each having a terminal end not covered by the polymeric binder;

a third electrically conductive reflecting layer (i) having a reflectivity of at least 50% to light emitted by at least one of the second semiconductor die or the wavelength-conversion material, (ii) disposed over a portion of the first face of the polymeric binder, (iii) disposed over a portion of the first face of the second semiconductor die, (iv) disposed over and electrically coupled to a first one of the at least two contacts of the second semiconductor die, and (v) electrically insulated from the first reflecting layer; and

a fourth electrically conductive reflecting layer (i) having a reflectivity of at least 50% to light emitted by at least one of the second semiconductor die or the wavelength-conversion material, (ii) disposed over a portion of the first face of the polymeric binder, (iii) disposed over a portion of the first face of the second semiconductor die, (iv) disposed over and electrically coupled to a second one of the at least two contacts of the second semiconductor die different from the first contact of the second semiconductor die, and (v) electrically insulated from the first, second, and third reflecting layers.

8. The electronic device of claim 7, wherein the third reflecting layer is electrically insulated from the second reflecting layer.

9. The electronic device of claim 7, wherein the third reflecting layer is electrically connected to the second reflecting layer.

10. The electronic device of claim 7, wherein a spacing between the semiconductor die and the second semiconductor die within the polymeric binder is in the range of 0.1 mm to 5 mm.

11. The electronic device of claim 1, wherein at least a portion of at least one of the first reflecting layer or the second reflecting layer is patterned or textured.

12. The electronic device of claim 11, wherein the pattern or texture comprises surface features having heights in the range of 0.1 μ

m to 50 μ

m.

13. The electronic device of claim 1, wherein the first reflecting layer is electrically coupled to the first contact via at least one of solder, conductive epoxy, anisotropic conductive adhesive, or anisotropic conductive film.

14. The electronic device of claim 1, wherein each of the first and second reflecting layers has a thickness in the range of 1 μ

m to 250 μ

m.

15. The electronic device of claim 1, wherein each of the first and second reflecting layers comprises a plurality of discrete stacked layers.

16. The electronic device of claim 1, wherein at least a portion of the polymeric binder is patterned or textured.

17. The electronic device of claim 1, wherein a surface of the first reflective layer opposite the first contact is substantially coplanar with a surface of the second reflective layer opposite the second contact.

18. The electronic device of claim 1, wherein the polymeric binder comprises at least one of-silicone or epoxy.

19. The electronic device of claim 1, wherein the wavelength-conversion material comprises at least one of a phosphor or quantum dots.

20. The electronic device of claim 1, wherein the bare-die light-emitting element comprises a semiconductor material comprising at least one of GaAs, AlAs, InAs, GaP, AlP, InP, ZnO, CdSe, CdTe, ZnTe, GaN, AlN, InN, silicon, or an alloy or mixture thereof.

21. The electronic device of claim 1, wherein the mixed light is substantially white light.

22. The electronic device of claim 21, wherein the substantially white light has a correlated color temperature in the range of 2000 K to 10,000 K.

23. The electronic device of claim 1, further comprising an optical element positioned to receive light from the semiconductor die.

24. The electronic device of claim 1, wherein the active semiconductor layers of the semiconductor die are not disposed on a semiconductor substrate.

25. The electronic device of claim 1, wherein the polymeric binder and the semiconductor die collectively define a rectangular solid having approximately 90°

corners between adjacent faces thereof.

26. The electronic device of claim 1, wherein the polymeric binder has a thickness between 5 μ

m and 4000 μ

m.

27. The electronic device of claim 26, wherein a dimension of the polymeric binder perpendicular to the thickness is between 25 μ

m and 50 mm.

28. The electronic device of claim 26, wherein (i) the first and second reflecting layers are substantially coplanar to each other, (ii) the first and second reflecting layers are substantially coplanar to a second face of the polymeric binder opposite the first face of the polymeric binder, (iii) the first reflecting layer has a substantially constant thickness, and (iv) the second reflecting layer has a substantially constant thickness approximately equal to the thickness of the first reflecting layer.

29. The electronic device of claim 1, further comprising a substrate having a plurality of conductive elements disposed thereon, wherein (i) the first reflecting layer is electrically coupled to a first conductive element and (ii) the second reflecting layer is electrically coupled to a second conductive element different from the first conductive element.

30. The electronic device of claim 29, wherein the first and second reflecting layers are electrically coupled to the first and second conductive elements via at least one of a conductive adhesive, an anisotropic conductive adhesive, a wire bond, or solder.