Light emitting devices and substrates with improved plating

• US 9,590,155 B2
• Filed: 03/14/2013
• Issued: 03/07/2017
• Est. Priority Date: 06/06/2012
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Hussell, Christopher P., Reiherzer, Jesse Colin, Welch, Erin
• Primary Examiner(s): Kraig, William F
• Assistant Examiner(s): Chin, Edward
• Application Number:
  US13/828,895
• Publication Number:
  US 20130328070A1
• Time in Patent Office: 1,454 Days
• Field of Search: 257/88, 257/E21.499, 257/E21.592, 257/E33.059, 257/E33.067, 257/81, 257/89, 257/98, 257/99, 428/172, 428/336, 428/434, 428/447, 428/457
• US Class Current: 1/1
• 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 25/0753 the devices being arranged next to each other
• 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 2933/0033 relating to semiconductor body packages
• 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 33/641 characterized by the materials
• CPC Class Codes: H05K 2201/0341 Intermediate metal, e.g. before reinforcing of conductors by plating
• CPC Class Codes: H05K 2201/099 Coating over pads, e.g. solder resist partly over pads
• CPC Class Codes: H05K 2201/10106 Light emitting diode [LED]
• CPC Class Codes: H05K 2201/2054 Light-reflecting surface, e.g. conductors, substrates, coatings, dielectrics
• CPC Class Codes: H05K 2203/073 Displacement plating, substitution plating or immersion plating, e.g. for finish plating
• CPC Class Codes: H05K 2203/1461 Applying or finishing the circuit pattern after another process, e.g. after filling of vias with conductive paste, after making printed resistors
• CPC Class Codes: H05K 3/244 Finish plating of conductors, especially of copper conductors, e.g. for pads or lands selective plating methods H05K3/243; finish plating of conductors made by printing techniques H05K3/246; solder as finish H05K3/3457, e.g. by plating H05K3/3473

Abstract

Light emitting devices and substrates are provided with improved plating. In one embodiment, a light emitting device can include a submount and one or more light emitting diodes (LED) chips disposed over the submount. In one embodiment, the submount can include a copper (Cu) substrate, a first metallic layer of material that is highly reflective disposed over the Cu substrate for increased brightness of the device, and a second metallic layer disposed between the Cu substrate and the first metallic layer for forming a barrier therebetween.

Claims

1. A light emitting device comprising:

a copper (Cu) substrate;

a first metallic layer comprising a reflective metal disposed over the Cu substrate for increasing brightness of the device, wherein the first metallic layer comprises silver (Ag);

a second metallic layer disposed between the Cu substrate and the first metallic layer for forming a diffusion barrier therebetween, wherein the second metallic layer contacts portions of the Cu substrate and the first metallic layer; and

one or more light emitting diode (LED) chips disposed over the Cu substrate,

wherein the Cu substrate comprises one or more electrically conductive traces and a conductive pad over which the first and second metallic layers are disposed, wherein a pap is disposed between the one or more electrically conductive traces and the conductive pad, wherein the gap between the conductive pad and the one or more electrically conductive traces is smaller in width than a second gap between portions of the first and second metallic layers disposed over each of the conductive pad and the one or more electrically conductive traces.

2. The device of claim 1, wherein the second metallic layer comprises electroless nickel (Ni).

3. The device of claim 1, wherein the first and second metallic layers are disposed over a vertical edge portion of the conductive pad or the one or more electrically conductive traces.

4. The device of claim 1, further comprising a layer of non-metallic reflective material disposed over and contacting a portion of the first metallic layer.

5. The device of claim 4, wherein the non-metallic reflective material comprises solder mask.

6. The device of claim 1, further comprising a layer of solder mask disposed over a portion of the second metallic layer.

7. The device of claim 1, wherein a retention material is disposed around the one or more LED chips.

8. The device of claim 7, wherein an encapsulant filling material is disposed within an inner wall of the retention material.

9. The device of claim 8, wherein one or more phosphors are disposed in the encapsulant.

10. The device of claim 1, further comprising a ceramic substrate over which the Cu substrate is disposed.

11. The device of claim 10, wherein one or more conductive vias are disposed through the ceramic substrate and electrically communicate with the Cu substrate.

12. The device of claim 10, further comprising a lens disposed over the one or more LED chips.

13. A light emitting device comprising:

a copper (Cu) substrate comprising one or more electrically conductive traces and a conductive pad over which first and second metallic layers are disposed;

the first metallic layer comprising a reflective metal disposed over the Cu substrate for increasing brightness of the device;

the second metallic layer disposed between the Cu substrate and the first metallic layer for forming a diffusion barrier therebetween, wherein the second metallic layer contacts portions of the Cu substrate and the first metallic layer; and

one or more light emitting diode (LED) chips disposed over the Cu substrate;

wherein a first gap is disposed between the one or more electrically conductive traces and the conductive pad, and wherein the first gap between the conductive pad and the one or more electrically conductive traces is smaller in width than a second gap between portions of the first and second metallic layers disposed over each of the conductive pad and the one or more electrically conductive traces.