Light emitting device and the manufacture method thereof

• US 20080054290A1
• Filed: 09/05/2007
• Published: 03/06/2008
• Est. Priority Date: 09/05/2006
• Status: Active Grant

• Current Assignee: Epistar Corporation
• Original Assignee: Epistar Corporation
• Inventors: Hsu, Chung-Yi, Shieh, Yuh-Ren, Fan, Hsuan-Cheng, Lin, Jin-Ywan, Huang, Chung-Kuei
• Granted Patent: US 8,067,780 B2
• Time in Patent Office: Days
• US Class Current: 257/99
• CPC Class Codes: H01L 2224/05001 Internal layers
• CPC Class Codes: H01L 2224/05023 the whole internal layer protruding from the surface
• CPC Class Codes: H01L 2224/05099 Material
• CPC Class Codes: H01L 2224/05557 comprising protrusions or indentations
• CPC Class Codes: H01L 2224/05568 the whole external layer protruding from the surface
• CPC Class Codes: H01L 2224/05573 Single external layer
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/08238 the bonding area connecting to a bonding area protruding from the surface of the item
• CPC Class Codes: H01L 2224/16 of an individual bump connector
• CPC Class Codes: H01L 24/05 of an individual bonding area
• CPC Class Codes: H01L 24/08 of an individual bonding area
• 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 2933/0016 relating to electrodes
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/38 with a particular shape
• 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

Abstract

This invention provides a light-emitting element and the manufacture method thereof. The light-emitting element is suitable for flip-chip bonding and comprises an electrode having a plurality of micro-bumps for direct bonding to a submount. Bonding within a relatively short distance between the light-emitting device and the submount can be formed so as to improve the heat dissipation efficiency of the light-emitting device.

Claims

1. A light-emitting element for bonding to a submount, the light-emitting element comprising:

a transparent substrate;

a first electricity semiconductor layer formed on the transparent substrate;

an active layer formed on the first electricity semiconductor layer;

a second electricity semiconductor layer formed on the active layer;

a contact layer formed on the second electricity semiconductor layer and forming ohmic contact therebetween; and

an electrode comprising a plurality of micro-bumps formed on the contact layer to bond the light-emitting element to a submount, wherein the plurality of micro-bumps provides a plurality of current channel.

2. The light-emitting element according to claim 1, wherein thickness of the plurality of micro-bumps is between 0.3 um and 20 um.

3. The light-emitting element according to claim 1, wherein ratio of summation of surface areas of the plurality of micro-bumps to that of the electrode is between 5% and 50%.

4. The light-emitting element according to claim 1, the shape of the plurality of micro-bumps is selected from the group consisting of a circle, a rectangle, a polygon, and the combination thereof.

5. The light-emitting element according to claim 4, wherein diameter of the plurality of circular micro-bumps is between 1 um and 250 um.

6. The light-emitting element according to claim 4, wherein length of short sides of the plurality of rectangular micro-bumps is between 1 um and 250 um.

7. The light-emitting element according to claim 1, wherein the plurality of micro-bumps are formed on the electrode out of one piece by etching or lift-off.

8. The light-emitting element according to claim 1 further comprising a submount bonded to the plurality of micro-bumps of the electrode by a direct bonding method.

9. The light-emitting element according to claim 8, wherein the direct bonding method is thermosonic bonding.

10. The light-emitting element according to claim 8, wherein the submount comprises a printed circuit board.

11. A light-emitting element for bonded to a submount, the light-emitting element comprising:

a transparent substrate;

a first electricity semiconductor layer formed on the transparent substrate;

an active layer formed on the first electricity semiconductor layer to receive a forward voltage to emit light;

a second electricity semiconductor layer formed on the active layer, comprising an uneven surface;

a contact layer formed on the second electricity semiconductor layer conforming to the surface shape thereof and forming ohmic contact therebetween;

an electrode formed on the contact layer, conforming to the surface shape of the contact layer to make the surfaces of the electrode have a plurality of micro-bumps to bond the light-emitting element to a submount via the plurality of micro-bumps, wherein the plurality of micro-bumps provides a plurality of current channels.

12. The light-emitting element according to claim 11, wherein thickness of the plurality of micro-bumps is between 0.3 um and 20 um.

13. The light-emitting element according to claim 11, wherein ratio of summation of surface areas of the plurality of micro-bumps to that of the electrode is between 5% and 50%.

14. The light-emitting element according to claim 11, wherein the shape of the plurality of micro-bumps is selected form the group consisting of a circle, a rectangle, a polygon, and the combination thereof.

15. The light-emitting element according to claim 14, wherein diameter of the plurality of circular micro-bumps is between 1 um and 250 um.

16. The light-emitting element according to claim 14, wherein length of short sides of the plurality of rectangular micro-bumps is between 1 um and 250 um.

17. The light-emitting element according to claim 11 further comprising a submount bonded to the plurality of micro-bumps of the electrode by a direct bonding method.

18. The light-emitting element according to claim 17, wherein the direct bonding method is thermosonic bonding.

19. The light-emitting element according to claim 17, wherein the submount comprises a printed circuit board.

20. A light-emitting element, comprising:

an LED comprising at least one electrode;

a submount comprising at least one bond pad; and

a plurality of micro-bumps located on the intermediate between the electrode and the bond pad, bonding the LED to the submount therethrough, wherein the plurality of micro-bumps provides a plurality of current channels.

21. The light-emitting element according to claim 20, wherein the plurality of micro-bumps are formed on the electrode out of one piece.

22. The light-emitting element according to claim 20, wherein the plurality of micro-bumps are formed on the bond pad out of one piece.

23. The light-emitting element according to claim 20, wherein thickness of the plurality of micro-bumps is between 0.3 um and 20 um.

24. The light-emitting element according to claim 20, wherein ration of summation of surface areas of the plurality of micro-bumps to that of the electrode is between 5% and 50%.

25. The light-emitting element according to claim 20, wherein the shape of the micro-bumps is selected form the group consisting of a circle, a rectangle, a polygon, and the combination thereof.

26. The light-emitting element according to claim 25, wherein diameter of the plurality of circular micro-bumps is between 1 um and 250 um.

27. The light-emitting element according to claim 25, wherein length of short sides of the plurality of rectangular micro-bumps is between 1 um and 250 um.

28. The light-emitting element according to claim 20, wherein the material of the plurality of micro-bumps is selected from the group consisting of Au, Ag, Al, and Cu.

29. The light-emitting element according to claim 20, wherein the submount comprises a printed circuit board.

30. The light-emitting element according to claim 20, wherein the LED further comprises:

a transparent substrate;

a first electricity semiconductor layer formed on the transparent substrate;

an active layer formed on the first electricity semiconductor layer to receive a forward voltage to emit light;

a second electricity semiconductor layer formed on the active layer; and

a contact layer formed on the second electricity semiconductor layer and forming ohmic contact therebetween,

wherein the electrode is formed on the contact layer.

31. A method of manufacturing a light-emitting element comprising the steps of:

providing an LED comprising a transparent substrate and at least one electrode;

providing a submount comprising at least one bond pad; and

forming a plurality of micro-bumps on the electrode or the bond pad.

32. The method of claim 31 further comprising bonding the LED to the submount by flip-chip bonding.

33. The method of claim 32, wherein the flip-chip bonding comprises direct flip-chip bonding.

34. The method of claim 33, wherein the direct flip-chip bonding comprises thermosonic bonding.

35. The method of claim 31, wherein the plurality of micro-bumps is formed on the electrode or the bond pad out of one piece.

36. The method of claim 31, wherein thickness of the plurality of micro-bumps is between 0.3 um and 20 um.

37. The method of claim 31, wherein ratio of summation of surface areas of the micro-bumps to that of the electrode is between 5% and 50%

38. The method of claim 31, wherein the shape of the plurality of micro-bumps is selected from the group consisting of a circle, a rectangle, a polygon, and the combination thereof.

39. The method of claim 38, wherein diameter of the plurality of circular micro-bumps is between 1 um and 250 um.

40. The method of claim 38, wherein length of short sides of the plurality of rectangular micro-bumps is between 1 um and 250 um.

41. The method of claim 31, wherein the material of the plurality of micro-bumps is selected from the group consisting of Au, Ag, Al, and Cu.

42. The method of claim 31, wherein the submount comprises a printed circuit board.