Light emitting devices and components having improved chemical resistance and related methods

• US 10,211,380 B2
• Filed: 12/01/2011
• Issued: 02/19/2019
• Est. Priority Date: 07/21/2011
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Lin, Shaow, Sievert, James, Reiherzer, Jesse Colin, Rayfield, Barry, Hussell, Christopher P.
• Primary Examiner(s): Wilczewski, Mary
• Assistant Examiner(s): Chiu, Tsz
• Application Number:
  US13/309,177
• Publication Number:
  US 20130020590A1
• Time in Patent Office: 2,637 Days
• Field of Search: 257 88, 257 98, 257E33057, 428174, 428434
• 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 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/8592 Applying permanent coating, e.g. protective coating
• 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 2924/181 Encapsulation
• CPC Class Codes: H01L 33/44 characterised by the coatings, e.g. passivation layer or anti-reflective coating
• 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: H01L 33/647 the elements conducting electric current to or from the semiconductor body
• CPC Class Codes: Y10T 428/24612 Composite web or sheet
• CPC Class Codes: Y10T 428/265 1 mil or less
• CPC Class Codes: Y10T 428/31663 As siloxane, silicone or silane
• CPC Class Codes: Y10T 428/31678 Of metal

Abstract

Light emitting devices and components having excellent chemical resistance and related methods are disclosed. In one embodiment, a component of a light emitting device can include a silver (Ag) portion, which can be silver on a substrate, and a protective layer disposed over the Ag portion. The protective layer can at least partially include an inorganic material for increasing the chemical resistance of the Ag portion.

Claims

1. A light emitting device comprising:

a substrate having an upper surface and comprising a leadframe, the leadframe comprising a thermal element and one or more electrical elements, wherein the thermal element and the one or more electrical elements comprise a silver containing material, wherein the silver containing material comprises silver and/or a silver alloy, wherein the thermal element is electrically and/or thermally isolated from the one or more electrical elements;

one or more light emitting diodes (LEDs) disposed on the upper surface of the substrate;

a first protective layer disposed on and covering all of the upper surface of the substrate, the first protective layer at least partially comprising an inorganic material for increasing chemical resistance of the silver-containing material of the thermal element of the substrate and/or the one or more electrical elements of the substrate, wherein the inorganic material contains some organic component, and wherein the first protective layer comprises a substantially uniform thickness; and

a filling material disposed on portions of the one or more LEDs and on portions of the first protective layer, wherein the filling material contains a phosphor material disposed therein,

wherein the leadframe, comprising the thermal element and the one or more electrical elements, comprises a material that is electrically and/or thermally conductive.

2. The device of claim 1, wherein the first protective layer at least partially comprises a silicon containing material selected from the group consisting of an organosilicate glass, organosilicate solution, organosilicate dispersion, organosilicate sol-gel, a Si-containing spin-on glass material, a spin-on polymer material, and a spin-on dielectric material.

3. The device of claim 2, wherein the spin-on glass material comprises a glass family selected from the group consisting of a silicate family, a phosphosilicate family, a siloxane family, a methylsiloxane family, a silsesquioxane family, and a dopant-containing variation of one of these families.

4. The device of claim 1, wherein the first protective layer comprises a thickness from approximately 50 nm to approximately 100 μ

m.

5. The device of claim 4, wherein the first protective layer comprises a thickness from approximately 50 nm to approximately 100 nm.

6. The device of claim 4, wherein the first protective layer comprises a thickness from approximately 100 nm to approximately 500 nm.

7. The device of claim 4, wherein the first protective layer comprises a thickness from approximately 0.5 μ

m to approximately 20 μ

m.

8. The device of claim 4, wherein the first protective layer is directly disposed over the substrate.

9. The device of claim 1, wherein a first LED is at least partially disposed between portions of the first protective layer and the substrate.

10. The device of claim 1, wherein the filling material is disposed on portions of the substrate.

11. The device of claim 1, wherein a second protective layer is disposed on the first protective layer.

12. The device of claim 1, wherein a second protective layer is disposed at least partially between portions of the first protective layer and portions of the filling material.

13. The component of claim 1, wherein a layer of material is disposed between the first protective layer and the substrate.

14. The device of claim 1, further comprising two or more LEDs.

15. The device of claim 1, further comprising first and second protective layers disposed over the substrate, wherein each protective layer comprises the inorganic material.

16. The component of claim 1, wherein the one or more LEDs emit a same color of light.

17. The device of claim 1, wherein the substrate is contained within a molded plastic body.

18. The device of claim 1, wherein the substrate is a layer of a submount of the device, wherein the layer is covered by the first protective layer.

19. The device of claim 1, wherein the substrate is contained within a ceramic body.

44. The device of claim 1, wherein the thermal element and the one or more electrical elements comprise a silver containing material.

20. A light emitting device comprising:

a substrate having an upper surface and comprising a leadframe, the leadframe comprising a thermal element and one or more electrical elements, wherein the thermal element and the one or more electrical elements comprise a silver containing material, wherein the silver containing material comprises silver and/or a silver alloy, wherein the thermal element is electrically and/or thermally isolated from the one or more electrical elements;

one or more light emitting diodes (LEDs) disposed on the upper surface of the substrate;

a first protective layer disposed on and covering all of the upper surface of the substrate, wherein the first protective layer comprises a substantially uniform thickness; and

a layer of filling material disposed on the one or more LEDs and on the first protective layer, wherein the filling material contains a phosphor material disposed therein;

wherein the first protective layer prevents gaseous chemicals or airborne elements that have permeated the filling material from interacting with the silver-containing material of the thermal element of the substrate and the one or more electrical elements of the substrate,

wherein the leadframe, comprising the thermal element and the one or more electrical elements, comprises a material that is electrically and/or thermally conductive.

21. The device of claim 20, wherein the first protective layer at least partially comprises an inorganic material, and wherein the inorganic material contains some organic component.

22. The device of claim 21, wherein the inorganic material comprises a silicon containing material selected from the group consisting of an organosilicate glass, organosilicate solution, organosilicate dispersion, organosilicate sol-gel, a Si-containing spin-on glass material, a spin-on polymer material, and a spin-on dielectric material.

23. The device of claim 22, wherein the spin-on glass material comprises a glass family selected from the group consisting of a silicate family, a phosphosilicate family, a siloxane family, a methylsiloxane family, a silsesquioxane family, and a dopant-containing variation of one of these families.

24. The device of claim 20, wherein the substrate is at least partially disposed over a copper (Cu) component.

25. The device of claim 24, wherein the substrate is at least partially disposed within a molded plastic body of the device.

26. The device of claim 24, wherein the substrate is at least partially disposed within a ceramic body of the device.

27. The device of claim 24, wherein the substrate is at least partially disposed over a submount of the device, the submount comprising a printed circuit board (PCB), a metal core printed circuit board (MCPCB), or an aluminum panel.

28. The device of claim 20, wherein the filling material comprises a silicone encapsulant having a selective amount of the phosphor material disposed therein.

29. The device of claim 28, wherein the silicone encapsulant comprises a methyl silicone.

30. The device of claim 28, wherein the silicone encapsulant comprises a phenyl silicone.

31. The device of claim 28, wherein a retention material is disposed about the silicone encapsulant.

32. The device of claim 28, wherein the silicone encapsulant is disposed within a cavity of the device.

33. The device of claim 20, wherein the first protective layer comprises a thickness from approximately 50 nm to approximately 100 μ

m.

34. The device of claim 33, wherein the first protective layer comprises a thickness from approximately 50 nm to approximately 100 nm.

35. The device of claim 33, wherein the first protective layer comprises a thickness from approximately 100 nm to approximately 500 nm.

36. The device of claim 33, wherein the first protective layer comprises a thickness from approximately 0.5 μ

m approximately 20 μ

m.

37. The device of claim 20, wherein the first protective layer is directly disposed over and covers the substrate.

38. The device of claim 20, wherein a portion of a first LED is at least partially disposed between portions of the first protective layer and the substrate.

39. The device of claim 20, wherein the filling material is disposed on portions of the substrate.

40. The device of claim 20, wherein a second protective layer is disposed on the first protective layer.

41. The device of claim 20, further comprising two or more LEDs.

42. The device of claim 20, further comprising first and second protective layers disposed over the substrate, wherein each protective layer comprises the inorganic material.

43. The device of claim 20, wherein the one or more LEDs emit a same color of light.

45. The device of claim 20, wherein the thermal element and the one or more electrical elements comprise a silver containing material.