LED package with structure and materials for high heat dissipation

• US 7,772,609 B2
• Filed: 10/26/2005
• Issued: 08/10/2010
• Est. Priority Date: 10/29/2004
• Status: Active Grant

• Current Assignee: LED Engin, Inc. (Ams-Osram AG)
• Original Assignee: Ledengin, Inc. (Ams-Osram AG)
• Inventors: Yan, Xiantao
• Primary Examiner(s): Bryant; Kiesha R
• Assistant Examiner(s): Yang; Minchul
• Application Number:
  US11/259,818
• Publication Number:
  US 20060091415A1
• Time in Patent Office: 1,749 Days
• Field of Search: 438/26, 438/788, 438/796, 438/99, 438/675, 438/688, 438/27, 438/29, 438/30, 438/31, 438/32, 438/38, 438/28, 257/26, 257/788, 257/796, 257/99, 257/675, 257/688, 257E33056-E33058, 257/93, 257/95, 257/98, 257/100, 257/705
• US Class Current: 257/99
• 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 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 33/60 Reflective elements
• CPC Class Codes: H01L 33/641 characterized by the materials

Abstract

LED packages are provided that include a material that is both thermally conductive and has a coefficient of thermal expansion that is matched to that of an LED. The material can be a ceramic such as aluminum nitride. The package has a body that includes a bottom surface and a cavity disposed into the body. The cavity has a floor for bonding to the LED so that the LED sits within the cavity. The thermally conductive material is disposed between the floor of the cavity and the bottom surface of the package. The body can be fabricated from a number of layers where the thermally conductive material is in a layer disposed between the floor and the bottom surface. The other layers of the body can also be fabricated from the thermally conductive material. A light emitting device is made by attaching the LED to the LED package.

Claims

1. A package for an LED and for attachment to a substrate comprising:

a top body layer;

an intermediate body layer bonded to the top body layer;

a cavity disposed through the top body layer and the intermediate body layer and having a floor for bonding to the LED;

a thermal conduction layer bonded to the intermediate body layer and having a first shape which includes a corner, a top surface forming the floor of the cavity and a bottom surface, the thermal conduction layer including a thermally conducting ceramic material disposed between the floor and the bottom surface and having a thermal conductivity greater than 14 W/m°

K; and

a metallization pattern including a central pad, the central pad plated on the bottom surface of the thermal conduction layer and having a second shape which has a continuously curved periphery without a corner, the first shape of the thermal conduction layer which includes a corner different than the second shape of the central pad which has a continuously curved periphery.

2. The package of claim 1 wherein the thermally conducting ceramic material includes aluminum nitride.

3. The package of claim 1 wherein the thermally conducting ceramic material includes alumina.

4. The package of claim 1 wherein the thermally conducting ceramic material has a thermal conductivity greater than 150 W/m°

K.

5. The package of claim 1 wherein the thermally conducting ceramic material has a coefficient of thermal expansion less than 15 ppm/°

C.

6. The package of claim 1 wherein the intermediate body layer includes a thermally conductive material between the top body layer and the thermal conduction layer.

7. The package of claim 1 wherein the top body layer and the intermediate body layer are each formed of a thermally conductive material.

8. The package of claim 7 wherein each of the three layers includes aluminum nitride.

9. The package of claim 1 further comprising an electrically nonconductive central bonding pad disposed on the floor of the cavity.

10. The package of claim 1 wherein an optically reflective material is disposed on a sidewall of the cavity.

13. The package of claim 6 wherein the top body layer comprises a ceramic material.

23. The package of claim 1 further comprising a metallization pattern disposed on a substantial portion of the top surface of the thermal conduction layer and sandwiched between the intermediate body layer and the thermal conduction layer.

11. A package for an LED comprising:

a body including

a top body layer and an intermediate body layer and a cavity disposed in the top body layer and the intermediate body layer and having a floor for bonding to the LED;

a thermal conduction layer having a bottom surface and a corner, the thermal conduction layer comprising a thermally conductive material disposed between the floor and the bottom surface, the thermally conductive material having a thermal conductivity greater than 14 W/m°

K and a coefficient of thermal expansion less than 15 ppm/°

C.;

a first metallization pattern disposed on a top surface of the thermal conduction layer, the first metallization pattern including a first thermally conductive central pad; and

a second metallization pattern plated on the bottom surface of the thermal conduction layer, the second metallization pattern including a second thermally conductive central pad and a separate electrical contact, the second thermally conductive central pad having a periphery without a corner and configured to provide a thermal path from the bottom surface to a substrate.

12. The package of claim 11 wherein a separation distance between the first thermally conductive central pad and the second thermally conductive central pad is a range of about 0.2 mm to 0.4 mm.

14. The package of claim 11 wherein the separate electrical contact is electrically coupled to the first thermally conductive central pad.

15. The package of claim 11 wherein the thermally conductive material is configured to conduct heat from the first thermally conductive central pad to the second thermally conductive central pad.

16. The package of claim 11 wherein the thermally conductive material has a thermal conductivity greater than 150 W/m°

K.

24. The package of claim 11 further comprising a metallization pattern disposed on a top surface of the thermal conduction layer and sandwiched between the intermediate body layer and the thermal conduction layer, the metallization pattern disposed on a substantial portion of the top surface of the thermal conduction layer.

17. A light emitting device comprising:

a body including

a cavity disposed in a top body layer and an intermediate body layer and having a floor for bonding to an LED,

a bottom surface, and

a thermally conducting ceramic material disposed between the floor and the bottom surface and having a thermal conductivity greater than 14 W/m°

K, the thermally conducting ceramic material forming a bottom surface which has rectangular shape;

a metallization pattern including a thermally conducting round pad centrally plated to the bottom surface of the body;

an LED bonded to the floor of the cavity; and

a luminescent material disposed over the LED.

18. The light emitting device of claim 17 wherein the thermally conducting ceramic material includes aluminum nitride.

19. The light emitting device of claim 17 wherein the thermally conducting ceramic material includes alumina.

20. The light emitting device of claim 17 wherein the thermally conducting ceramic material has a thermal conductivity greater than 150 W/m°

K.

21. The light emitting device of claim 17 wherein the thermally conducting ceramic material has a coefficient of thermal expansion less than 15 ppm/°

C.

22. The light emitting device of claim 17 further comprising a thermal insulating material disposed over the LED.

25. The package of claim 17 further comprising a metallization pattern sandwiched between the floor and a substantial portion of the intermediate layer.