Molded chip fabrication method and apparatus

• US 9,093,616 B2
• Filed: 03/25/2011
• Issued: 07/28/2015
• Est. Priority Date: 09/18/2003
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Leung, Michael S., Tarsa, Eric J., Ibbetson, James
• Primary Examiner(s): Armand, Marc
• Application Number:
  US13/072,371
• Publication Number:
  US 20110169038A1
• Time in Patent Office: 1,586 Days
• Field of Search: 257/79, 257/13, 257 80-103, 257/918, 257/E51.018, 257/E51.019, 257/E51.022, 257/E25.028
• US Class Current: 1/1
• CPC Class Codes: H01L 21/565 Moulds
• CPC Class Codes: H01L 2224/2518 being disposed on at least two different sides of the body, e.g. dual array
• 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 27/15 including semiconductor components having potential barriers, specially adapted for light emission
• 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 2924/12041 LED
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H01L 2924/1815 Shape
• CPC Class Codes: H01L 2933/0041 relating to wavelength conversion elements
• CPC Class Codes: H01L 33/50 Wavelength conversion elements
• CPC Class Codes: H01L 33/504 Elements with two or more wavelength conversion materials

Abstract

A method and apparatus for coating a plurality of semiconductor devices that is particularly adapted to coating LEDs with a coating material containing conversion particles. One method according to the invention comprises providing a mold with a formation cavity. A plurality of semiconductor devices are mounted within the mold formation cavity and a curable coating material is injected or otherwise introduced into the mold to fill the mold formation cavity and at least partially cover the semiconductor devices. The coating material is cured so that the semiconductor devices are at least partially embedded in the cured coating material. The cured coating material with the embedded semiconductor devices is removed from the formation cavity. The semiconductor devices are separated so that each is at least partially covered by a layer of the cured coating material. One embodiment of an apparatus according to the invention for coating a plurality of semiconductor devices comprises a mold housing having a formation cavity arranged to hold semiconductor devices. The formation cavity is also arranged so that a curable coating material can be injected into and fills the formation cavity to at least partially covering the semiconductor devices.

Claims

1. A light emitting diode (LED), comprising:

a plurality of semiconductor layers comprising an active region between two oppositely doped layers;

positive and negative contacts on the same surface of said semiconductor layers and coplanar with each other, said active region emitting light in response to an electrical signal applied to said contacts; and

a conformal coat of matrix material covering surfaces of said semiconductor layers, with an exposed portion of each of said contacts being uncovered by said matrix material and coplanar with an adjacent surface of said matrix material.

2. The LED of claim 1, wherein said contacts are accessible from the bottom of said semiconductor layers.

3. The LED of claim 1, wherein said matrix material comprises one or more phosphors.

4. The LED of claim 1, wherein said matrix material comprises one or more phosphors distributed in a binder.

5. The LED of claim 1, wherein said active region light passes through said matrix material wherein at least some of said active region light is converted to a different wavelength by said matrix material.

6. The LED of claim 1, wherein said active region light comprises blue or UV light, and said matrix material absorbs at least some of said active region light and re-emits light at a different wavelength.

7. The LED of claim 6, wherein said matrix material re-emits yellow or green light.

8. The LED of claim 1, wherein said semiconductor layers further comprise shaped side surfaces, wherein said matrix material conforms to said shaped side surfaces.

9. The LED of claim 1, wherein said semiconductor layers further comprise top and side surfaces, wherein said matrix material covers at least some of said top and side surfaces.

10. The LED of claim 1, wherein said matrix material further comprises scattering particles.

11. The LED of claim 1, wherein at least some of said active region light passes through said matrix material, said matrix material such that said active region light passes through substantially the same amount of matrix material.

21. The LED of claim 1, wherein said semiconductor layer light comprises blue or UV light, and conversion material absorbs at least some of said semiconductor layer light and re-emits light at a different wavelength.

22. The LED of claim 6, wherein said conversion material re-emits yellow or green light.

12. A light emitting diode (LED), comprising:

a plurality of semiconductor layers in a lateral geometry;

positive and negative terminals on the same side of said semiconductor layers and coplanar with each other, said semiconductor layers emitting light in response to an electrical signal applied to said terminals; and

a conformal coat of conversion material covering surfaces of said semiconductor layers, said conversion material converting at least some of said semiconductor layer light, with an exposed portion of each of said terminals being uncovered by said conversion material and coplanar with an adjacent surface of said conversion material.

13. The LED of claim 12, wherein at least a portion of said terminals being uncovered by said matrix material.

14. The LED of claim 12, said LED comprising angled side surfaces to increase light extraction.

15. The LED of claim 12, wherein said semiconductor layers have a top and side surfaces covered by said conversion material.

16. The LED of claim 15, wherein said semiconductor layer light passes through substantially the same amount of conversion material.

17. The LED of claim 15, wherein said terminals are accessible from the bottom of said semiconductor layers.

18. The LED of claim 15, wherein said conversion material comprises one or more phosphors distributed in a binder.

19. The LED of claim 18, wherein said conversion material is distributed uniformly in said binder.

20. The LED of claim 18, wherein said conversion material is distributed non-uniformly in said binder.

23. A light emitting diode (LED), comprising:

semiconductor layers;

contacts on said semiconductor layers on the same surface of said semiconductor layers and coplanar with each other;

a conversion material as a conformal coat on said semiconductor layers, with an exposed portion of each of said contacts being uncovered by said conversion material and coplanar with an adjacent surface of said conversion material.

24. The LED of claim 23, wherein said semiconductor layers further comprise top and bottom surfaces, conversion material covering at least a portion of said semiconductor layers top and side surfaces.

25. The LED of claim 23, wherein said contacts are accessible from the bottom surface.

26. The LED of claim 23, wherein said semiconductor layers are in a lateral geometry.