Molded chip fabrication method and apparatus

• US 10,546,978 B2
• Filed: 07/21/2009
• Issued: 01/28/2020
• 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): Kalam, Abul
• Application Number:
  US12/506,989
• Publication Number:
  US 20090278156A1
• Time in Patent Office: 3,843 Days
• Field of Search: None
• 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 light emitting diode (LED) is disclosed comprising a plurality of semiconductor layers with a first contact on the bottom surface of the semiconductor layers and a second contact on the top surface of the semiconductor layer. A coating is included that comprises a cured binder and a conversion material that at least partially covers the semiconductor layers, wherein the second contact extends through the coating and is exposed on the same plane as the top surface of the coating. An electrical signal applied to the first and second contacts is conducted through the coating to the semiconductor layers causing the LED to emit light. In other embodiments first and second contacts are accessible from one side of the LED. A coating is included that comprises a cured binder and a conversion material. The coating at least partially covers the semiconductor layers, with the first and second contacts extending through the coating and exposed on the same plane as a surface of the coating. An electrical signal applied to the first and second contacts is conducted through the coating to the semiconductor layers causing the LED to emit light.

Claims

1. A light emitting diode (LED) comprising:

a plurality of semiconductor layers defining a structure having a first surface, a second surface opposite the first surface, and at least one angled side;

a top contact coupled to the first surface;

a bottom contact coupled to the second surface; and

a coating layer comprising a cured binder and a conversion material, wherein the coating layer covers all of the at least one angled side and further covers a side surface of the top contact and a side surface of the bottom contact, wherein the surface of the coating layer adjacent to said top contact is planar and not above said top contact, wherein none of the coating layer is over the first surface of the structure;

in which a top surface of the top contact is exposed along a top surface of said LED and a bottom surface of the bottom contact is exposed along a bottom surface of the LED.

2. The LED of claim 1, wherein said coating layer comprises a phosphor loaded binder.

3. The LED of claim 2, wherein said conversion material is distributed in a substantially uniform manner in said binder.

4. The LED of claim 1, wherein said coating layer further comprises scattering particles.

5. The LED of claim 1, wherein said coating layer is formed over said semiconductor layers in a mold formation cavity.

6. The LED of claim 1, wherein said semiconductor layers are coated simultaneously with other similar LEDs.

7. The LED of claim 6, wherein said semiconductor layers are separated from the others in similar LEDs that are simultaneously coated.

8. The LED of claim 1, wherein said bottom contact is in electrical contact with said semiconductor layers such that an electrical bias applied across said top and bottom contacts causes said LED to emit light.

9. The LED of claim 1, wherein said coating layer comprises a planar top surface, wherein said top contact is exposed in the same plane as said planar top surface.

10. The LED of claim 1, wherein the top contact is accessible from the top surface of said coating layer.

11. The LED of claim 1, wherein the bottom contact is accessible from the bottom surface of said coating layer.

12. A light emitting diode (LED) comprising:

a plurality of semiconductor layers defining a structure having a bottom surface, a top surface opposite the bottom surface, and one or more angled sides;

a first contact on the bottom surface of the structure.

a second contact on the top surface of the structure; and

a coating comprising a cured binder and a conversion material, wherein the coating layer covers all of the one or more angled sides and further covers a side surface of the first contact and a side surface of the second contact, wherein said first contact extends through said coating layer and is exposed as a bottom surface of the LED, said second contact extends through said coating layer and is exposed as a top surface of said LED, wherein said coating layer is planar adjacent to said first contact and is substantially cube shaped; and

wherein none of the coating layer is over the top surface of the structure.

13. The LED of claim 12, wherein said conversion material is distributed in a substantially uniform manner in said binder.

14. The LED of claim 12, wherein said coating layer is formed over said semiconductor layers in a mold formation cavity.

15. The LED of claim 12, emitting a white light combination of light from the conversion material and semiconductor layers.

16. The LED of claim 12, wherein the second contact is accessible from the top surface of said coating layer.

17. The LED of claim 12, wherein the first contact is accessible from the bottom surface of said coating layer.

18. The LED of claim 12, wherein said coating layer is cube shaped.

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

a plurality of semiconductor layers defining a structure having a bottom surface, a top surface opposite the bottom surface, and at least one angled side;

a top contact on the plurality of semiconductor layers;

a bottom contact opposite said top contact; and

a coating layer comprising a cured binder and a conversion material, such that the coating layer covers all of the at least one angled side and further covers a side surface of the top contact and a side surface of the bottom contact, in which said top contact extends through said coating layer such that the coating layer is absent from an exposed surface of the top contact, wherein the surface of the coating layer adjacent said top contact is planar and the surface of the coating covering said angled side is planar;

wherein light emitting from said LED passes through substantially the same thickness of said coating layer; and

wherein none of the coating layer is over the top surface of the structure.

20. The LED of claim 19, wherein said coating layer comprises a phosphor loaded binder.

21. The LED of claim 19, wherein said conversion material is distributed in a substantially uniform manner in said binder.

22. The LED of claim 19, wherein said coating layer further comprises scattering particles.

23. The LED of claim 19, wherein said bottom contact is in electrical contact with said semiconductor layers such that an electrical signal applied across said top and bottom contacts causes said LED to emit light.

24. The LED of claim 23, wherein said bottom contact extends through said coating layer and is exposed at the bottom surface of said coating.

25. The LED of claim 19, wherein the top contact is accessible from the planar top surface of said coating layer.

26. The LED of claim 19, wherein the bottom contact is accessible from the planar bottom surface of said coating layer.

27. The LED of claim 19, wherein said coating layer comprises an angled side and a vertical side of substantially equal thickness.

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

a plurality of semiconductor layers defining a structure having a bottom surface, a top surface opposite the bottom surface, and one or more angled sides;

a top contact coupled to the plurality of semiconductor layers;

a bottom contact coupled to the plurality of semiconductor layers opposite said top contact;

a conformal coat layer of matrix material comprising a cured binder and a conversion material, wherein the conformal coat layer covers all of the one or more angled sides and further covers a side surface of the top contact and a side surface of the bottom contact, in which the top contact extends through the conformal coat layer such that the conformal coat layer is absent from an exposed surface of the top contact and such that none of the conformal coat layer is over the top surface of the structure, wherein the surface of the coating layer covering the side surface of said top contact is planar and not above said top contact.

29. The LED of claim 28, wherein said matrix material comprises a phosphor loaded binder.

30. The LED of claim 29, wherein said matrix material is distributed in a substantially uniform manner.

31. The LED of claim 28, wherein said coat layer further comprises scattering particles.

32. The LED of claim 28, wherein said coat layer is formed over said semiconductor layers in a mold formation cavity.

33. The LED of claim 28, wherein said semiconductor layers are coated simultaneously with other similar LEDs.

34. The LED of claim 33, wherein said semiconductor layers are separated from the others in similar LEDs that are simultaneously coated.

35. The LED of claim 28, wherein said top contact extends to the same height as the top surface of said coat layer on said semiconductor layers.

36. The LED of claim 28, wherein said bottom contact is in electrical contact with said semiconductor layers such that an electrical bias applied across said top and bottom contacts causes said LED to emit light.

37. The LED of claim 28, wherein said coat layer comprises a planar top surface, wherein said top contact is exposed in the same plane as said top surface.

38. The LED of claim 28, wherein the top contact is accessible from the top surface of said coat layer.

39. The LED of claim 28, wherein the bottom contact is accessible from the bottom surface of said coat layer.