Light emitting devices

• US 8,455,908 B2
• Filed: 12/23/2011
• Issued: 06/04/2013
• Est. Priority Date: 02/16/2011
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Hussell, Christopher P., Reiherzer, Jesse Colin, Clark, Joseph, Welch, Erin R. F.
• Primary Examiner(s): LE, DUNG ANH
• Application Number:
  US13/336,540
• Publication Number:
  US 20120205689A1
• Time in Patent Office: 529 Days
• Field of Search: 257 79- 81, 257 88- 89, 257/95, 257 98-100, 313/483, 313498-500, 362/555, 362/800
• US Class Current: 257/98
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48137 the bodies being arranged next to each other, e.g. on a common substrate
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2224/83192 wherein the layer connectors are disposed only on another item or body to be connected to the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/92247 the second connecting process involving a wire connector
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 25/167 comprising optoelectronic devices, e.g. LED, photodiodes
• 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 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• 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 2924/01322 Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H01L 33/52 Encapsulations
• CPC Class Codes: H01L 33/60 Reflective elements

Abstract

Light emitting devices and methods are disclosed. In one embodiment a light emitting device can include a submount and a plurality of light emitting diodes (LEDs) disposed over the submount. At least a portion of the submount can include a reflective layer at least partially disposed below a solder mask. One or more layers within the submount may include one or more holes, a rough surface texture, or combinations thereof to improve adhesion within the device. The device can further include a retention material dispensed about the plurality of LEDs. Devices and methods are disclosed for improved solder mask adhesion.

Claims

1. A light emitting device, comprising:

a submount for supporting one or more light emitting diodes (LEDs);

wherein the submount comprises;

a conductive layer;

a reflective layer disposed over the conductive layer, wherein at least one hole is disposed in the reflective layer such that the reflective layer forms a sidewall of the hole; and

a layer of solder mask disposed over the reflective layer such that at least a portion of the solder mask is disposed in the hole.

2. The light emitting device of claim 1, wherein the hole terminates at an upper surface of the conductive layer.

3. The light emitting device of claim 1, wherein the at least one hole is disposed in the conductive layer, such that the reflective layer and the conductive layer form sidewalls of the hole.

4. The light emitting device of claim 3, further comprising a dielectric layer.

5. The light emitting device of claim 4, wherein the at least one hole terminates at an upper surface of the dielectric layer.

6. The light emitting device of claim 1, wherein the submount further comprises a barrier layer disposed below the reflective layer.

7. The light emitting device of claim 6, wherein the conductive layer comprises copper (Cu), the reflective layer comprises silver (Ag), and the barrier layer comprises nickel (Ni).

8. The light emitting device of claim 1, wherein the conductive layer comprises at least one electrically conductive trace.

9. The light emitting device of claim 1, wherein a plurality of holes is disposed in the reflective layer.

10. The light emitting device of claim 9, wherein the plurality of holes comprises a matrix.

11. The light emitting device of claim 9, wherein the plurality of holes comprises a random pattern.

12. The light emitting device of claim 9, wherein the plurality of holes are disposed along an edge of the reflective layer.

13. The light emitting device of claim 9, wherein the plurality of holes comprise at least one of a circle, square, star, and asymmetric shape, or combinations thereof.

14. The light emitting device of claim 1, wherein the at least one hole comprises a depth ranging between approximately 0.2 and 500 micrometers (μ

m).

15. The light emitting device of claim 1, comprising one or more light emitting diodes.

16. A light emitting device, comprising:

a submount;

a plurality of light emitting diodes (LEDs) disposed over the submount, wherein the LEDs are electrically connected via one or more electrical connectors; and

a retention material disposed about the plurality of LEDs, wherein the retention material covers at least a portion of the one or more electrical connectors; and

wherein the submount comprises;

a reflective layer disposed over the conductive layer, wherein at least one hole is disposed in the reflective layer such that the reflective layer forms a sidewall of the hole; and

a layer of solder mask disposed over the reflective layer such that at least a portion of the solder mask is disposed in the hole.

17. The light emitting device of claim 16, wherein the hole terminates at an upper surface of the conductive layer.

18. The light emitting device of claim 17, wherein the at least one hole is disposed in the conductive layer, such that the reflective layer and the conductive layer form sidewalls of the hole.

19. The light emitting device of claim 18, further comprising a dielectric layer.

20. The light emitting device of claim 19, wherein the at least one hole terminates at an upper surface of the dielectric layer.

21. The light emitting device of claim 18, wherein a plurality of holes is disposed in the reflective layer.

22. The light emitting device of claim 21, wherein the plurality of holes comprises a matrix.

23. The light emitting device of claim 21, wherein the plurality of holes comprises a random pattern.

24. The light emitting device of claim 21, wherein the plurality of holes are disposed along an edge of the reflective layer.

25. The light emitting device of claim 21, wherein the plurality of holes comprise at least one of a circle, square, star, asymmetric shape, or combinations thereof.

26. The light emitting device of claim 16, wherein the at least one hole comprises a depth ranging between approximately 0.2 and 500 micrometers (μ

m).