Light emitting diode package with enhanced heat conduction

• US 9,502,612 B2
• Filed: 10/07/2013
• Issued: 11/22/2016
• Est. Priority Date: 09/20/2009
• Status: Active Grant

• Current Assignee: LED Wafer Solutions LLC
• Original Assignee: Viagan Limited
• Inventors: Margalit, Mordehai
• Primary Examiner(s): ZARNEKE, DAVID A
• Application Number:
  US14/047,715
• Publication Number:
  US 20140042479A1
• Time in Patent Office: 1,142 Days
• Field of Search: 257/98, 257/99
• US Class Current: 1/1
• CPC Class Codes: H01L 2224/24 of an individual high density interconnect connector
• 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 2924/12044 OLED
• CPC Class Codes: H01L 2924/1461 MEMS
• CPC Class Codes: H01L 2933/0066 relating to arrangements for conducting electric current to or from the semiconductor body
• CPC Class Codes: H01L 33/10 with a light reflecting structure, e.g. semiconductor Bragg reflector
• CPC Class Codes: H01L 33/382 the electrode extending partially in or entirely through the semiconductor body
• CPC Class Codes: H01L 33/46 Reflective coating, e.g. dielectric Bragg reflector
• CPC Class Codes: H01L 33/48 characterised by the semiconductor body packages
• CPC Class Codes: H01L 33/483 Containers
• CPC Class Codes: H01L 33/486 adapted for surface mounting
• CPC Class Codes: H01L 33/52 Encapsulations
• 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 33/64 Heat extraction or cooling elements
• CPC Class Codes: H01L 33/647 the elements conducting electric current to or from the semiconductor body

Abstract

A light emitting diode (LED) device and packaging with enhance heat conduction. An LED in a wafer level processing (WLP) package is disclosed using vias in the silicon to route the electrical connections to the LED backside and a dedicated hole in the silicon with a direct heat conduction route from the LED to the printed circuit board. Certain layers act to promote mechanical, electrical, thermal, or optical characteristics of the device. The device avoids or ameliorates heat dissipation problems found in conventional LED devices. Some embodiments include a plurality of optically permissive layers, including an optically permissive cover substrate comprising phosphors and/or quantum dots.

Claims

1. A light emitting device, comprising:

a substrate having opposing first and second substrate surfaces;

a semiconductor LED including doped and intrinsic regions thereof, said semiconductor LED having opposing first and second LED surfaces, said first LED surface disposed on the first substrate surface;

a thermally conductive layer disposed on the second LED surface of the semiconductor LED;

a carrier wafer disposed on the thermally conductive layer;

at least one optically reflective surface disposed between said carrier wafer and said semiconductor LED; and

a substantially optically transmissive layer disposed proximal to the second substrate surface,

wherein the carrier wafer and the thermally conductive layer define a relief to expose at least a portion of the second LED surface.

2. The light emitting device of claim 1, said at least one optically reflective surface comprising metal.

3. The light emitting device of claim 1, said at least one optically reflective surface comprising a dielectric stack.

4. The light emitting device of claim 1, wherein said semiconductor LED is affixed to said carrier wafer with an adhesive material which has the property of high thermal conductivity.

5. The light emitting device of claim 1, wherein said semiconductor LED is affixed to said carrier wafer with an adhesive material which has the property of optical diffusion.

6. The light emitting device of claim 1, wherein said semiconductor LED is affixed to said carrier wafer with an adhesive material which has the property of optical reflection.

7. The light emitting device of claim 1, wherein said semiconductor LED is affixed to said carrier wafer with an adhesive material which has the property of optical transmissivity.

8. The light emitting device of claim 1, further comprising at least one spacer attached to said carrier wafer;

whereby, said at least one optically reflective surface is affixed thereto.

9. The light emitting device of claim 1, said thermally conductive layer comprises metal.

10. The light emitting device of claim 1, said thermally conductive layer comprises an organic material with a physical property of high thermal conductivity.

11. The light emitting device of claim 1, wherein the relief has a surface area displacement of 250,000 square microns.

12. The light emitting device of claim 1, wherein the relief has a surface area displacement of at least 700 microns by 700 microns.