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

• US 8,680,558 B1
• Filed: 09/30/2013
• Issued: 03/25/2014
• 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:
  US14/041,193
• Publication Number:
  US 20140061705A1
• Time in Patent Office: 176 Days
• Field of Search: 257/98, 257/89, 257/80, 438/27, 438/28, 438/29, 438/25, 438/31, 313/503, 313/501, 313/512, 362/231, 362/97.3, 362/237, 362/606
• US Class Current: 257/98
• CPC Class Codes: H01L 21/00 Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
• CPC Class Codes: H01L 2224/13022 the bump connector being at least partially embedded in the surface
• CPC Class Codes: H01L 2224/16145 the bodies being stacked
• CPC Class Codes: H01L 2224/73259 Bump and HDI connectors
• 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 25/00 Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereofdevices consisting of a plurality of solid state components formed in or on a common substrate H01L27/00; photovoltaic modules or arrays of photovoltaic cells H01L31/042 ; panels or arrays of photo electrochemical cells H01G9/2068
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 27/14 including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation radiation-sensitive components structurally associated with one or more electric light sources only H01L31/14; couplings of light guides with optoelectronic elements G02B6/42
• CPC Class Codes: H01L 29/00 Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor H01L31/00 - H01L33/00, H10K10/00, H10N take precedence; details other than of semiconductor bodies or of electrodes thereof H01L23/00; devices consisting of a plurality of solid state components formed in or on a common substrate H01L27/00
• 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 2924/01005 Boron [B]
• 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 2933/0033 : relating to semiconductor body packages
• CPC Class Codes: H01L 2933/0041 : relating to wavelength conversion elements
• CPC Class Codes: H01L 31/0203 : Containers; Encapsulations , e.g. encapsulation of photodiodesfor photovoltaic devices H01L31/048; for organic photosensitive devices H10K30/80
• CPC Class Codes: H01L 31/022425 : for solar cells
• CPC Class Codes: H01L 31/02322 : comprising luminescent members, e.g. fluorescent sheets upon the device
• CPC Class Codes: H01L 31/02327 : the optical elements being integrated or being directly associated to the device, e.g. back reflectors optical coatings H01L31/0216
• CPC Class Codes: H01L 31/048 : Encapsulation of modules
• 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 33/501 : characterised by the materials, e.g. binder
• CPC Class Codes: H01L 33/505 : characterised by the shape, e.g. plate or foil
• CPC Class Codes: H01L 33/60 : Reflective elements
• CPC Class Codes: H05B 33/02 : Details
• CPC Class Codes: H05B 33/12 : Light sources with substantially two-dimensional radiating surfaces
• 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. A composite wafer comprising:

a solid volume of a polymeric binder having a first surface and a second surface opposite the first surface;

suspended within the polymeric binder, a plurality of semiconductor dies each (i) having a first face, a second face opposite the first face, and at least one sidewall spanning the first and second faces, and (ii) being a bare-die light-emitting element comprising a plurality of active semiconductor layers that cooperatively emit light;

a reflecting layer disposed on a surface of the polymeric binder or disposed within at least a portion of the polymeric binder proximate at least one semiconductor die; and

disposed on the first face of each semiconductor die, at least two spaced-apart contacts each having a free terminal end (i) at least a portion of which is not covered by the polymeric binder and (ii) available for electrical connection, the contacts each contacting a different active semiconductor layer of the semiconductor die,

wherein (i) at least a portion of the polymeric binder is transparent to a wavelength of light emitted by at least one of the semiconductor dies, (ii) the polymeric binder contains therein a wavelength-conversion material for absorption of at least a portion of light emitted from at least one of the semiconductor dies and emission of converted light having a different wavelength, converted light and unconverted light emitted by at least one semiconductor die combining to form substantially white light having a correlated color temperature in the range of 2000 K to 10,000 K, (iii) a variation in color temperature of the white light emitted when each semiconductor die is individually energized is less than 500 K, and (iv) the reflecting layer has a reflectivity of at least 50% to a wavelength of light emitted by at least one semiconductor die or to a wavelength of light emitted by the wavelength-conversion material.

2. The composite wafer of claim 1, wherein at least portions of the contacts of at least some of the semiconductor dies protrude from the polymeric binder.

3. The composite wafer of claim 1, wherein at least portions of the contacts of all of the semiconductor dies protrude from the polymeric binder.

4. The composite wafer of claim 1, wherein at least a portion of each said sidewall of at least some of the semiconductor dies protrudes from the first surface of the polymeric binder.

5. The composite wafer of claim 1, wherein the polymeric binder comprises at least one of silicone or epoxy.

6. The composite wafer of claim 1, wherein the wavelength-conversion material comprises at least one of a phosphor or quantum dots.

7. The composite wafer of claim 1, wherein each semiconductor die comprises a bare-die light-emitting diode.

8. The composite wafer of claim 1, wherein each semiconductor die 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.

9. The composite wafer of claim 1, wherein the substantially white light has a variation in color temperature of less than four MacAdam ellipses across the composite wafer.

10. The composite wafer of claim 1, wherein the substantially white light has a variation in color temperature of less than two MacAdam ellipses across the composite wafer.

11. The composite wafer of claim 1, wherein the polymeric binder has a substantially uniform thickness with a thickness variation less than 10%.

12. The composite wafer of claim 1, wherein a thickness of the polymeric binder above each of the plurality of semiconductor dies is the same to within 5%.

13. The composite wafer of claim 1, wherein the semiconductor dies are arranged in an array having substantially equal distances between semiconductor dies in at least a first direction.

14. The composite wafer of claim 13, wherein the array of semiconductor dies has substantially equal distances between semiconductor dies in a second direction different from the first direction.

15. The composite wafer of claim 1, wherein at least a portion of the surface of the polymeric binder is textured with a texture for enhancing light extraction from the polymeric binder.

16. The composite wafer of claim 15, wherein the texture has an average roughness in the range of about 0.5 μ

m to about 10 μ

m.

17. The composite wafer of claim 1, further comprising at least one optical element positioned to receive light from at least one of the semiconductor dies.

18. The composite wafer of claim 17, wherein the at least one optical element comprises a plurality of optical elements each associated with at least one semiconductor die.

19. The composite wafer of claim 1, wherein the reflecting layer comprises at least one of (i) a reflecting film or (ii) a plurality of particles.

20. The composite wafer of claim 1, wherein the polymeric binder comprises a plurality of discrete regions, at least one of which comprises the polymeric binder without the wavelength-conversion material.

21. The composite wafer of claim 1, wherein the active semiconductor layers of at least one semiconductor die are not disposed on a semiconductor substrate.

22. The composite wafer of claim 1, wherein the polymeric binder comprises a plurality of shaped regions, each shaped region (i) associated with at least one semiconductor die and (ii) having a shape substantially identical to shapes of the other shaped regions.

23. The composite wafer of claim 1, wherein the reflectivity of the reflecting layer to the wavelength of light emitted by at least one semiconductor die or to the wavelength of light emitted by the wavelength-conversion material is at least 75%.

24. The composite wafer of claim 1, wherein the variation in color temperature of the white light emitted when each semiconductor die is individually energized is less than 250 K.

25. The composite wafer of claim 1, wherein a thickness of the polymeric binder above a first semiconductor die is different from a thickness of the polymeric binder above a second semiconductor die different from the first semiconductor die.