Semiconductor light emitting device mounting substrates including a conductive lead extending therein and methods of packaging same

• US 20060157726A1
• Filed: 01/14/2005
• Published: 07/20/2006
• Est. Priority Date: 01/14/2005
• Status: Active Grant

• Current Assignee: CREE Led Incorporated (Smart Global Holdings Incorporated)
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Negley, Gerald H., Fu, Yankun, Loh, Ban P.
• Granted Patent: US 7,777,247 B2
• Time in Patent Office: Days
• US Class Current: 257/100
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• 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 2924/00014 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 2924/01019 Potassium [K]
• CPC Class Codes: H01L 2924/01068 Erbium [Er]
• CPC Class Codes: H01L 2924/12041 LED
• CPC Class Codes: H01L 2924/3011 Impedance
• CPC Class Codes: H01L 33/486 adapted for surface mounting
• 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

Abstract

A mounting substrate for a semiconductor light emitting device includes a thermally conductive mounting block. The mounting block has, in a first face thereof, a cavity that is configured to mount a semiconductor light emitting device therein and to reflect light that is emitted by the semiconductor light emitting device that is mounted therein away from the cavity. A conductive lead inserted into the mounting block extends into the cavity. The conductive lead is electrically isolated from the mounting block and has an exposed contact portion in the cavity. The conductive lead may be a plurality of conductive leads each having an exposed contact portion at different locations in the cavity. Related packaging methods also may be provided.

Claims

1. A mounting substrate for a semiconductor light emitting device comprising:

a thermally conductive mounting block having in a first face thereof a cavity that is configured to mount a semiconductor light emitting device therein and to reflect light that is emitted by the semiconductor light emitting device that is mounted therein away from the cavity; and

a conductive lead inserted in the mounting block and extending into the cavity, the conductive lead being electrically isolated from the mounting block and having an exposed contact portion in the cavity.

2. The mounting substrate of claim 1 wherein the conductive lead comprises a plurality of conductive leads each having an exposed contact portion at different locations in the cavity.

3. The mounting substrate of claim 2 further comprising cutouts in a sidewall of the cavity proximate respective ones of the contact portions that provide access to the contact portions from the cavity.

4. The mounting substrate of claim 3 wherein the sidewall of the cavity comprises a sloped sidewall.

5. The mounting substrate of claim 1 further comprising a reflective coating in the cavity.

6. The mounting substrate of claim 1 wherein the mounting block comprises a solid metal block.

7. The mounting substrate of claim 6 wherein the metal block comprises a solid steel block, a solid aluminum block or a solid copper block.

8. The mounting substrate of claim 1 in combination with a semiconductor light emitting device that is mounted in the cavity.

9. The mounting substrate of claim 8 wherein the semiconductor light emitting device comprises a plurality of semiconductor light emitting devices.

10. The mounting substrate of claim 8 in further combination with a lens that extends across the cavity.

11. The mounting substrate of claim 10 further comprising an encapsulant in the cavity that optically couples the at least one semiconductor light emitting diode to the lens.

12. The mounting substrate of claim 11 wherein the lens is flexibly fitted to the mounting block to flex with expansion and contraction of the encapsulant.

13. The mounting substrate of claim 11 wherein the lens is at least one of latched or adhesively attached to the mounting block.

14. The mounting substrate of claim 10 in further combination with a coating comprising phosphor on the lens.

15. The mounting substrate of claim 10 wherein the lens includes phosphor dispersed therein.

16. The mounting substrate of claim 8 in further combination with a coating comprising phosphor on the semiconductor light emitting device.

17. The mounting substrate of claim 8 wherein the semiconductor light emitting device comprises a semiconductor light emitting diode.

18. The mounting substrate of claim 8 in combination with an optical coupling media in the cavity at least partially surrounding the semiconductor light emitting device.

19. The mounting substrate of claim 8 in combination with a wire electrically connecting the semiconductor light emitting device to the contact portion.

20. The mounting substrate of claim 19 wherein the wire connects an anode of the semiconductor light emitting device to the contact portion and wherein the mounting substrate further comprises a second conductive lead extending through the mounting block into the cavity that is electrically isolated from the mounting block and has an exposed contact portion in the cavity and wherein the substrate is further in combination with a second wire electrically connecting a cathode of the semiconductor light emitting device to the contact portion of the second conductive lead.

21. The mounting substrate of claim 1 wherein the conductive lead comprises a molded lead having a non-conductive mold portion that electrically isolates the conductive lead from the mounting block and a lead.

22. The mounting substrate of claim 21 wherein the mounting block includes a passageway extending inwardly to the cavity from a side face of the mounting block and wherein the molded lead is positioned in the passageway.

23. The mounting substrate of claim 21 wherein the mounting block includes a channel in the second face and extending inwardly to the cavity from a side face of the mounting block and wherein the molded lead is positioned in the channel.

24. The mounting substrate of claim 21 wherein the mold portion further comprises a key portion that mates with a socket in the mounting block to position the molded lead in the mounting block.

25. The mounting substrate of claim 21 wherein the mold portion further comprises an access passage extending from the lead to one of the first face or the second face that allows access for a tool to the lead during molding of the mold portion.

26. The mounting substrate of claim 25 wherein the access passage comprises a plurality of access passages at displaced locations.

27. The mounting substrate of claim 2 wherein the plurality of conductive leads comprises a molded lead frame having a non-conductive mold portion that electrically isolates the conductive leads from the mounting block.

28. The mounting substrate of claim 27 wherein the mounting block includes passageways extending inwardly to the cavity from a side face of the mounting block and wherein the molded lead frame is positioned in the passageways with each of the conductive leads extending through a respective one of the passageways.

29. The mounting substrate of claim 21 wherein the mold portion further comprises a key portion that mates with a socket in the mounting block to position the molded lead in the mounting block.

30. The mounting substrate of claim 29 wherein the mounting block includes channels in the second face and extending inwardly to the cavity from a side face of the mounting block and wherein the molded lead frame is positioned in the channels with each of the conductive leads extending through a respective one of the channels.

31. The mounting substrate of claim 1 wherein the conductive lead includes a surface mount technology (SMT) lead on an end thereof extending from the mounting block.

32. The mounting substrate of claim 31 wherein the SMT lead comprises a J-bend or a gullwing lead.

33. The mounting substrate of claim 32 wherein the mounting block further comprises a cutaway portion in the second face configured to receive the J-bend lead.

56. The mounting substrate of claim 28 wherein the mounting block further comprises a cutaway portion in the second face configured to receive the J-bend lead.

34. A mounting substrate for a semiconductor light emitting device comprising:

a thermally conductive mounting block having a first and second opposing face and a side face therebetween, the first face including thereon a mounting surface that is configured to receive a semiconductor light emitting device thereon;

a conductive lead extending inwardly from the side face of the mounting block inserted into the mounting block, the conductive lead being electrically isolated from the mounting block and having an exposed contact pad on a surface thereof facing the first face of the mounting block; and

a passageway in the first face of the mounting block and extending towards the exposed contact pad to allow passage of an electrical connection from the first face of the mounting block to the exposed contact pad.

35. The mounting substrate of claim 34 further comprising a reflector on the first face of the mounting block and defining a cavity around the semiconductor light emitting device that is configured to reflect light that is emitted by the semiconductor light emitting device away from the cavity, wherein the passageway is in communication with the cavity.

36. The mounting substrate of claim 34 wherein the conductive lead comprises a plurality of conductive leads each having a contact pad and wherein the passageway comprises a plurality of passageways extending to respective ones of the contact pads.

37. The mounting substrate of claim 34 wherein the mounting block comprises a solid metal block.

38. The mounting substrate of claim 37 wherein the metal block comprises a solid steel block, a solid aluminum block or a solid copper block.

39. The mounting substrate of claim 35 in combination with a semiconductor light emitting device that is mounted in the cavity.

40. The mounting substrate of claim 39 wherein the semiconductor light emitting device comprises a plurality of semiconductor light emitting devices.

41. The mounting substrate of claim 39 in further combination with a lens that extends across the cavity.

42. The mounting substrate of claim 41 further comprising an encapsulant in the cavity that optically couples the at least one semiconductor light emitting diode to the lens.

43. The mounting substrate of claim 42 wherein the lens is flexibly fitted to the mounting block to flex with expansion and contraction of the encapsulant.

44. The mounting substrate of claim 42 wherein the lens is at least one of latched or adhesively attached to the mounting block.

45. The mounting substrate of claim 39 wherein the semiconductor light emitting device comprises a semiconductor light emitting diode.

46. The mounting substrate of claim 39 in combination with an optical coupling media in the cavity at least partially surrounding the semiconductor light emitting device.

47. The mounting substrate of claim 39 in combination with a wire electrically connecting the semiconductor light emitting device to the contact portion.

48. The mounting substrate of claim 34 wherein the conductive lead comprises a molded lead having a non-conductive mold portion that electrically isolates the conductive lead from the mounting block and a lead.

49. The mounting substrate of claim 48 wherein the mounting block includes a passageway extending inwardly to the passageway in the first face from a side face of the mounting block and wherein the molded lead is positioned in the passageway from the side face.

50. The mounting substrate of claim 48 wherein the mounting block includes a channel in the second face and extending inwardly to the passageway in the first face from a side face of the mounting block and wherein the molded lead is positioned in the channel.

51. The mounting substrate of claim 48 wherein the mold portion further comprises a key portion that mates with a socket in the mounting block to position the molded lead in the mounting block.

52. The mounting substrate of claim 36 wherein the plurality of conductive leads comprises a molded lead frame having a non-conductive mold portion that electrically isolates the conductive leads from the mounting block.

53. The mounting substrate of claim 52 wherein the mounting block includes passageways extending inwardly to the passageway in the first face from a side face of the mounting block and wherein the molded lead frame is positioned in the passageways from the side face with each of the conductive leads extending through a respective one of the passageways from the side face.

54. The mounting substrate of claim 34 wherein the conductive lead includes a surface mount technology (SMT) lead on an end thereof extending from the mounting block.

55. The mounting substrate of claim 54 wherein the SMT lead comprises a J-bend or a gullwing lead.

57. A semiconductor light emitting device packaging method comprising:

fabricating a solid metal mounting block including first and second opposing metal faces, the first metal face including therein a cavity configured to mount a semiconductor light emitting device therein and to reflect light that is emitted by the semiconductor light emitting device that is mounted therein away from the cavity;

7fabricating a molded lead having a non-conductive molded body portion and a conductive lead extending therethrough;

inserting the molded lead into the mounting block and extending into the cavity, the molded lead having an exposed contact portion in the cavity;

mounting the semiconductor light emitting device in the cavity; and

electrically connecting the semiconductor device to the exposed contact portion.

58. A method according to claim 57 wherein the molded lead is isolated from the mounting block by the non-conductive body portion.

59. A method according to claim 58 wherein mounting is followed by:

placing a lens across the cavity.

60. A method according to claim 59 further comprising:

coating the lens with phosphor.

61. A method according to claim 58 further comprising:

placing an optical coupling media in the cavity at least partially surrounding the semiconductor light emitting device.