High power and high brightness white LED assemblies and method for mass production of the same

• US 20050189551A1
• Filed: 02/26/2004
• Published: 09/01/2005
• Est. Priority Date: 02/26/2004
• Status: Abandoned Application

• Current Assignee: Gang Grant Peng, Hui Peng
• Original Assignee: Gang Grant Peng, Hui Peng
• Inventors: Peng, Hui, Peng, Gang Grant
• Application Number:
  US10/787,816
• Publication Number:
  US 20050189551A1
• Time in Patent Office: Days
• US Class Current: 257/94
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48463 the connecting portion on the bonding area of the semiconductor or solid-state body being a ball bond
• CPC Class Codes: H01L 25/0756 Stacked arrangements of devices
• 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 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/08 with a plurality of light emitting regions, e.g. laterally discontinuous light emitting layer or photoluminescent region integrated within the semiconductor body H01L27/15 takes precedence
• CPC Class Codes: H01L 33/38 with a particular shape

Abstract

High power and high brightness light emitting diode (LED) assemblies emitting white light are disclosed. The present invention also discloses methods for cost effective mass production of the high power and high brightness LED assemblies with high throughput.

Claims

1. A light emitting diode (LED) assembly emitting light of mixing colors, comprising:

a first epitaxial layer comprising a first N-type cladding layer, a first P-type cladding layer, and a first active layer sandwiched between said first N-type and said first P-type cladding layers, and emitting light of first wavelength;

a second epitaxial layer comprising a second N-type cladding layer, a second P-type cladding layer, and a second active layer sandwiched between said second N-type and said second P-type cladding layers, and emitting light of second wavelength;

wherein one side of said second epitaxial layer bonding to one side of said first epitaxial layer;

a second electrode for wire bonding disposed on the other side of said second epitaxial layer;

a submount that is electrically conductive;

wherein one side of said submount bonding to the other side of said first epitaxial layer.

2. The light emitting diode (LED) assembly emitting light of mixing colors of claim 1,

further comprises a first electrode disposed on the other side of said submount.

3. The light emitting diode (LED) assembly emitting light of mixing colors of claim 2,

wherein said first electrode has the opposite polarity to that of said second electrode so that said first epitaxial layer and said second epitaxial layer are electrically connected in serial.

4. The light emitting diode (LED) assembly emitting light of mixing colors of claim 2,

further comprises a third electrode;

wherein said second electrode having the same polarity as that of said first electrode; and

wherein said third electrode having the opposite polarity to that of said first and said second electrodes so that said first epitaxial layer and said second epitaxial layer are electrically controlled separately.

5. The light emitting diode (LED) assemblies emitting light of mixing colors of claim 1,

further comprising a reflector/Ohmic layer sandwiched between said submount and said first epitaxial layer.

6. The light emitting diode (LED) assembly emitting light of mixing colors of claim 5,

wherein said reflector/Ohmic layer comprises metals selected from a group comprising Al, Au, Ag, In, Ni, Ti, Pd, Pt, and alloys of said metals.

7. The light emitting diode (LED) assembly emitting light of mixing colors of claim 1,

wherein said second electrode for wire bonding is patterned for improving current crowding, distributing current more uniformly, increasing current density, and fully utilizing the material of said active layer.

8. The light emitting diode (LED) assembly emitting light of mixing colors of claim 7,

wherein said patterned second electrode is a ring-grid-shape.

9. The light emitting diode (LED) assembly emitting light of mixing colors of claim 7,

wherein said patterned second electrode is a multi-ring-plus-shape.

10. The light emitting diode (LED) assembly emitting light of mixing colors of claim 1,

wherein a material system of said first active layer comprises elements selected from a group comprising Al, As, B, Bi, Ga, In, N, and P.

11. The light emitting diode (LED) assembly emitting light of mixing colors of claim 1,

wherein a material system of said first active layer is selected from a group comprising AlGaInP, InGaN, GaInNP, GaNP, GaAsP, AlGaAs, AlGaP, InGaP, and GaP:

N.

12. The light emitting diode (LED) assembly emitting light of mixing colors of claim 1,

wherein a material system of said second active layer comprises elements selected from a group comprising Al, Be, Cd, Ga, In, N, S, Se, Te, and Zn.

13. The light emitting diode (LED) assembly emitting light of mixing colors of claim 1,

wherein a material system of said second active layer is selected from a group comprising GaInN, AlGaInN, GaN, BeZnCdSe, BeZnCdTe, ZnSe, ZnCdSe, ZnSeTe, SiC(6H), and ZnSSe.

27. The light emitting diode (LED) assembly emitting light of mixing colors of claim 1,

wherein a material system of said second active layer comprises elements selected from a group comprising Al, Be, Cd, Ga, In, N, S, Se, Te, and Zn.

28. The light emitting diode (LED) emitting light of mixing colors of claim 1, wherein a material system of said second active layer selected from a group comprising GaInN, AlGaInN, GaN, BeZnCdSe, BeZnCdTe, ZnSe, ZnCdSe, ZnSeTe, SiC(6H), and ZnSSe.

14. A light emitting diode (LED) assembly emitting light of mixing colors, comprising:

a first epitaxial layer comprising a first cladding layer and a first active layer emitting light of first wavelength;

a second epitaxial layer comprising a second cladding layer and a second active layer emitting light of second wavelength;

wherein said first active layer bonding to said second active layer;

a second electrode for wire bonding disposed on said second cladding layer; and

a submount that is electrically conductive;

wherein one side of said submount bonded to said first cladding layer.

15. The light emitting diode (LED) assembly emitting light of mixing colors of claim 14,

further comprising a first electrode disposed on the other side of said submount.

16. The light emitting diode (LED) assembly emitting light of mixing colors of claim 15,

wherein said first electrode has the opposite polarity to that of said second electrode so that said first epitaxial layer and said second epitaxial layer are electrically connected in serial.

17. The light emitting diode (LED) assembly emitting light of mixing colors of claim 16,

further comprises a multiple quantum barrier-well (MQBW) layer sandwiched between said first active layer and said second active layer.

18. The light emitting diode (LED) assembly emitting light of mixing colors of claim 15,

further comprises a third electrode;

wherein said first electrode having the same polarity as that of said second electrode; and

wherein said third electrode having an opposite polarity to that of said first and said second electrodes so that said first epitaxial layer and said second epitaxial layer are electrically controlled separately.

19. The light emitting diode (LED) assembly emitting light of mixing colors of claim 18,

further comprises two MQBW layers;

wherein one of said MQBW layers sandwiched between said third electrode and said first epitaxial layer and the other of said MQBW layers sandwiched between said third electrode and said second epitaxial layer.

20. The light emitting diode (LED) assembly emitting light of mixing colors of claim 14,

further comprises a reflector/Ohmic layer sandwiched between said submount and said first epitaxial layer.

21. The light emitting diode (LED) assembly emitting light of mixing colors of claim 20,

wherein said reflector/Ohmic layer comprises materials selected from a group comprising metals of Al, Au, Ag, In, Ni, Ti, Pd, Pt, and alloys of said metals.

22. The light emitting diode (LED) assembly emitting light of mixing colors of claim 14,

wherein said second electrode for wire bonding is patterned for improving current crowding, distributing current more uniformly, increasing current density, and fully utilizing the material of said active layer.

23. The light emitting diode (LED) assembly emitting light of mixing colors of claim 22,

wherein said patterned second electrode is a ring-grid-shape.

24. The light emitting diode (LED) assembly emitting light of mixing colors of claim 22,

wherein said patterned second electrode is a multi-ring-plus-shape.

25. The light emitting diode (LED) assembly emitting light of mixing colors of claim 14,

wherein a material system of said first active layer comprises elements selected from a group comprising Al, As, B, Bi, Ga, In, N, and P.

26. The light emitting diode (LED) assembly emitting light of mixing colors of claim 14,

wherein a material system of said first active layer is selected from a group comprising AlGaInP, InGaN, GaInNP, GaNP, GaAsP, AlGaAs, AlGaP, InGaP, and GaP:

N.

29. A method for manufacturing light emitting diode (LED) assemblies emitting light of mixing colors, comprises the steps:

bonding a first epitaxial layer of a first light emitting diode (LED) wafer emitting light of first wavelength to a second epitaxial layer of a second light emitting diode (LED) wafer emitting light of second wavelength to form a LED assembly wafer;

removing the substrate of said first LED wafer, and said first epitaxial layer exposed;

disposing a reflector/Ohmic layer on exposed said first epitaxial layer;

bonding a submount to said reflector/Ohmic layer;

removing the substrate of said second LED wafer, and said second epitaxial layer exposed;

disposing a second electrode on exposed said second epitaxial layer;

dicing said LED assembly wafer into individual LED assemblies.

30. The method for manufacturing light emitting diode (LED) assemblies emitting light of mixing colors of claim 29, further comprises:

a step of disposing a third electrode to either said first epitaxial layer or said second epitaxial layer before bonding said first epitaxial layer to said second epitaxial layer;

a step of etching through said second epitaxial layer at a pre-determined area until said third electrode exposed and then disposing an Ohmic contact pad on exposed said third electrode for wire bonding before dicing said LED assembly wafer.

31. A lam for LEDs (including LED assemblies), comprises:

a base for mounting a LED;

a hemisphere-shaped dome formed from a material selected from a group comprising epoxy, glass, and plastics;

wherein said material being doped with nano-particles so that the refraction index of said material is the same or similar to that of the material of the top epitaxial layer of said LED; and

wherein the diameter of said hemisphere-shaped dome being equal to or larger than the production of said refraction index of said material of said dome and the size of said LED.

32. The lam for LEDs (including LED assemblies) of claim 31, further comprises a reflective cup surrounding said dome for reflecting emitted light of said LED to desired direction.