Semiconductor light emitting device packages and methods

• US 20080258168A1
• Filed: 04/18/2007
• Published: 10/23/2008
• Est. Priority Date: 04/18/2007
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Hiller, Norbert, Edmond, John, Jackson, Mitch, Loh, Ban P., Cannon, Nathaniel O., Medendorp, Nicholas W.
• Granted Patent: US 7,964,888 B2
• Time in Patent Office: Days
• US Class Current: 257/99
• CPC Class Codes: H01L 2224/32245 the item being metallic
• CPC Class Codes: H01L 2224/32257 the layer connector connecting to a bonding area disposed in a recess of the surface of the item
• CPC Class Codes: H01L 2224/45124 Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/4554 Coating
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48471 the other connecting portion not on the bonding area being a ball bond, i.e. wedge-to-ball, reverse stitch
• CPC Class Codes: H01L 2224/49113 the connectors connecting different bonding areas on the semiconductor or solid-state body to a common bonding area outside the body, e.g. converging wires
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2224/97 the devices being connected to a common substrate, e.g. interposer, said common substrate being separable into individual assemblies after connecting
• CPC Class Codes: H01L 24/97 the devices being connected to a common substrate, e.g. interposer, said common substrate being separable into individual assemblies after connecting
• CPC Class Codes: H01L 25/167 comprising optoelectronic devices, e.g. LED, photodiodes
• 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 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• 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 2924/01322 Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases
• CPC Class Codes: H01L 2924/12041 LED
• CPC Class Codes: H01L 2924/12042 LASER
• CPC Class Codes: H01L 2924/14 Integrated circuits
• CPC Class Codes: H01L 2924/181 : Encapsulation
• CPC Class Codes: H01L 2924/1815 : Shape
• CPC Class Codes: H01L 33/486 : adapted for surface mounting
• CPC Class Codes: H01L 33/52 : Encapsulations
• CPC Class Codes: H01L 33/54 : having 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

A submount for a light emitting device package includes a rectangular substrate. A first bond pad and a second bond pad are on a first surface of the substrate. The first bond pad includes a die attach region offset toward a first end of the substrate and configured to receive a light emitting diode thereon. The second bond pad includes a bonding region between the first bond pad and the second end of the substrate and a second bond pad extension that extends from the bonding region along a side of the substrate toward a corner of the substrate at the first end of the substrate. First and second solder pads are a the second surface of the substrate. The first solder pad is adjacent the first end of the substrate and contacts the second bond pad. The second solder pad is adjacent the second end of the substrate and contacts the first bond pad. Related LED packages and methods of forming LED packages are disclosed.

Claims

1. A submount for a light emitting device package, comprising:

a generally rectangular substrate having a first surface and a second surface opposite the first surface, a first end and a second end opposite the first end;

a first bond pad on the first surface of the substrate, wherein the first bond pad includes a die attach region offset toward the first end of the substrate and configured to receive a light emitting diode thereon;

a second bond pad on the first surface of the substrate, wherein the second bond pad includes a bonding region that is between the first bond pad and the second end of the substrate and a second bond pad extension that extends from the bonding region along a side of the substrate toward a corner of the substrate at the first end of the substrate; and

first and second solder pads on the second surface of the substrate, wherein the first solder pad is adjacent the first end of the substrate and the second solder pad is adjacent the second end of the substrate, and wherein the second bond pad is in electrical contact with the first solder pad and the first bond pad is in electrical contact with the second solder pad.

2. The submount of claim 1, wherein the substrate includes a castellation at the corner of the substrate and an electrical trace on the castellation that extends from the first surface of the substrate to the second surface of the substrate and that electrically connects the second bond pad and the first solder pad.

3. The submount of claim 1, wherein the side of the substrate comprises a first side and the corner of the substrate comprises a first corner, and wherein the first bond pad further comprises a first bond pad extension that extends from the die attach region along a second side of the substrate, opposite the first side of the substrate, towards a second corner of the substrate at the second end of the substrate and diagonally opposed to the first corner.

4. The submount of claim 3, wherein the substrate includes a castellation at the second corner of the substrate, and a second electrical trace on the second castellation that extends from the first surface of the substrate to the second surface of the substrate and that electrically connects the first bond pad and the second solder pad.

5. The submount of claim 1, further comprising a neutral pad on the second surface of the substrate between the first solder pad and the second solder pad, wherein the neutral pad is electrically isolated from the first solder pad and the second solder pad.

6. The submount of claim 4, wherein the first corner and the second corner are diagonally opposed to one another across the substrate.

7. The submount of claim 1, wherein the substrate comprises an electrically insulating material.

8. The submount of claim 7, wherein the substrate comprises aluminum nitride, silicon carbide, diamond, and/or alumina.

9. The submount of claim 1, further comprising at least one via hole through the substrate extending from the first surface of the substrate to the second surface of the substrate, and a conductive material in the at least one via hole and electrically connecting the first bond pad and the second solder pad.

10. The submount of claim 1, wherein the first bond pad includes:

a seed layer on the substrate; and

a thermal spreading layer on the seed layer, wherein the thermal spreading layer comprises a layer of copper having a thickness greater than about 5 μ

m.

11. The submount of claim 10, wherein the first bond pad further comprises a barrier layer on the thermal spreading layer opposite the seed layer.

12. The submount of claim 11, wherein the first bond pad further comprises a reflective layer on the barrier layer opposite the thermal spreading layer.

13. The submount of claim 10, wherein the first bond pad further comprises a first barrier layer on the thermal spreading layer opposite the seed layer and a second barrier layer between the seed layer and the thermal spreading layer.

14. A light emitting device package, comprising:

a generally rectangular substrate having a first surface and a second surface opposite the first surface, a first end and a second end opposite the first end;

a first bond pad on the first surface of the substrate, wherein the first bond pad includes a die attach region offset from a center of the first surface toward the first end of the substrate and configured to receive a light emitting diode thereon;

a second bond pad on the first surface of the substrate, wherein the second bond pad includes a bonding region that is between the first bond pad and the second end of the substrate and a second bond pad extension that extends from the bonding region along a side of the substrate toward a corner of the substrate at the first end of the substrate;

first and second solder pads on the second surface of the substrate, wherein the first solder pad is adjacent the first end of the substrate and the second solder pad is adjacent the second end of the substrate, and wherein the second bond pad is in electrical contact with the first solder pad and the first bond pad is in electrical contact with the second solder pad;

a light emitting device having an electrical contact and mounted on the first bond pad;

a bond wire bonded to the electrical contact of the light emitting device and to the second bond pad; and

an encapsulant on the first surface of the substrate.

15. The package of claim 14, wherein the encapsulant comprises an integrated lens arranged over the light emitting device, wherein the integrated lens has an optical axis that is aligned over a center of the light emitting device, so that the integrated lens is offset from a center of the substrate toward the first end of the substrate.

16. The package of claim 14, further comprising an ESD protection chip including an electrical contact, the ESD protection chip mounted on the first bond pad, and a second bond wire electrically connecting the electrical contact of the ESD protection chip and the second bond pad.

17. The package of claim 14, wherein the substrate includes a castellation at the corner of the substrate and an electrical trace on the castellation that extends from the first surface of the substrate to the second surface of the substrate and that electrically connects the second bond pad and the first solder pad.

18. The package of claim 14, wherein the first bond pad further comprises a first bond pad extension that extends from the die attach region along a second side of the substrate towards a second corner of the substrate at the second end of the substrate.

19. The package of claim 18, wherein the substrate includes a castellation at the second corner of the substrate, and a second electrical trace on the second castellation that extends from the first surface of the substrate to the second surface of the substrate and that electrically connects the first bond pad and the second solder pad.

20. The package of claim 19, wherein the first corner and the second corner are diagonally opposed to one another across the substrate.

21. The package of claim 14, further comprising a neutral pad on the second surface of the substrate between the first solder pad and the second solder pad, wherein the neutral pad is electrically isolated from the first solder pad and the second solder pad.

22. The package of claim 14, wherein the substrate comprises an electrically insulating material.

23. The package of claim 22, wherein the substrate comprises aluminum nitride and/or alumina.

24. The package of claim 14, further comprising at least one via hole through the substrate extending from the first surface of the substrate to the second surface of the substrate, and a conductive material in the at least one via hole and electrically connecting the first bond pad and the second solder pad.

25. The package of claim 14, wherein the encapsulant comprises a wavelength conversion material and/or a disperser.

26. The package of claim 14, further comprising a wavelength conversion material between the light emitting device and the encapsulant.

27. The package of claim 14, further comprising a secondary optical element on the encapsulant.

28. A method of forming a submount for a light emitting diode (LED) package, comprising:

providing a generally rectangular substrate having a first surface and a second surface opposite the first surface, a first end and a second end opposite the first end, a first corner at the first end and a second corner at the second end and diagonally across the substrate from the first corner;

forming a seed layer on the first surface of the substrate;

patterning the seed layer to form a first bond pad pattern and a second bond pad pattern on the first surface of the substrate;

forming first bond pad on the first bond pad pattern, wherein the first bond pad includes a die attach region offset from a center of the first surface toward the first end of the substrate and configured to receive a light emitting diode thereon;

forming a second bond pad on the second bond pad pattern, wherein the second bond pad includes a bonding region that is between the first bond pad and the second end of the substrate and a second bond pad extension that extends from the bonding region along a side of the substrate toward a corner of the substrate at the first end of the substrate; and

etching the first bond pad and the second bond pad to increase a separation between the first bond pad and the second bond pad.

29. The method of claim 28, further comprising forming first and second solder pads on the second surface of the substrate, wherein the first solder pad is adjacent the first end of the substrate and the second solder pad is adjacent the second end of the substrate, and wherein the second bond pad is in electrical contact with the first solder pad and the first bond pad is in electrical contact with the second solder pad.

30. The method of claim 29, further comprising removing material from the first corner and the second corner to provide respective first and second castellations at the first corner and the second corner;

forming a first electrical via on the first castellation, the first electrical via electrically connecting the second bond pad and the first solder pad; and

forming a second electrical via on the second castellation, the second electrical via electrically connecting the first bond pad and the second solder pad.

31. A method of forming a plurality of packaged light emitting diodes, comprising:

providing a sheet of ceramic material including a two-dimensional array of light emitting devices mounted thereon;

providing a mold including a plurality of cavities therein;

dispensing a liquid encapsulant material in respective ones of the plurality of cavities;

bringing the sheet of ceramic material into contact with the mold so that respective ones of the light emitting devices extend into a corresponding one of the plurality of cavities; and

at least partially curing the liquid encapsulant so as to form encapsulant coatings around the respective light emitting devices.

32. The method of claim 31, wherein the sheet of ceramic material includes a plurality of metallized holes therethrough, the method further comprising:

separating the sheet of ceramic material along separation lines that extend through a subset of the plurality of holes to thereby define individual light emitting diode substrates including castellations at corners thereof, the castellations including respective electrical vias thereon extending from first surfaces of the substrates to second surfaces of the substrates opposite the first surfaces.