Light emitting diode package and method for fabricating same

• US 20090108281A1
• Filed: 10/31/2007
• Published: 04/30/2009
• Est. Priority Date: 10/31/2007
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Keller, Bernd, Yuan, Thomas Cheng-Hsin, Medendorp, Nicholas JR.
• Granted Patent: US 9,070,850 B2
• Time in Patent Office: Days
• US Class Current: 257/98
• CPC Class Codes: H01L 2224/32245 the item being metallic
• 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 2224/73265 Layer and wire connectors
• 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 2924/01019 Potassium [K]
• CPC Class Codes: H01L 2924/01087 Francium [Fr]
• CPC Class Codes: H01L 2933/0025 relating to coatings
• CPC Class Codes: H01L 2933/0033 relating to semiconductor body packages
• CPC Class Codes: H01L 2933/0058 relating to optical field-shaping elements
• CPC Class Codes: H01L 33/486 adapted for surface mounting
• CPC Class Codes: H01L 33/54 having a particular shape
• CPC Class Codes: H01L 33/58 Optical field-shaping 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
• 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

An LED package comprising a submount having a top and bottom surface with a plurality of top electrically and thermally conductive elements on its top surface. An LED is included on one of the top elements such that an electrical signal applied to the top elements causes the LED to emit light. The electrically conductive elements also spread heat from the LED across the majority of the submount top surface. A bottom thermally conductive element is included on the bottom surface of said submount and spreads heat from the submount, and a lens is formed directly over the LED. A method for fabricating LED packages comprising providing a submount panel sized to be separated into a plurality of LED package submounts. Top conductive elements are formed on one surface of the submount panel for a plurality of LED packages, and LEDs are attached to the top elements. Lenses are molded over the LEDs and the substrate panel is singulated to separate it into a plurality of LED packages.

Claims

1. An LED package, comprising:

a submount having a top and bottom surface;

a plurality of top electrically and thermally conductive elements on said top surface of said submount;

an LED on one of said top elements, an electrical signal applied to said top elements causing said LED to emit light, said electrically conductive elements spreading heat from said LED across the majority of said submount top surface;

a bottom thermally conductive element on said bottom surface not in electrical contact with said top elements and conducting heat from said submount; and

a lens formed directly over said LED.

2. The LED package of claim 1, wherein said top elements comprise an attach pad with an integral first contact pad, and a second contact pad.

3. The LED package of claim 2, wherein said LED is mounted to said attach pad, with said attach pad extends beyond the edge of said LED on the top surface of said submount.

4. The LED package of claim 3, wherein said attach pad extends radial beyond the edge of said LED on said top surface.

5. The LED package of claim 1, wherein said top elements cover more that 50% of said top surface.

6. The LED package of claim 1, further comprising first and second mounting pads on said bottom surface and a plurality of conductive vias running through said submount.

7. The LED package of claim 6, wherein said first and second mounting pads are at least partially aligned with said first and second contact pads, respectively, said vias running between and providing an electrical path between said mounting pads and said contact pads.

8. The LED package of claim 1, further comprising an ESD element to protect said LED from electrostatic discharge.

9. The LED package of claim 1, further comprising a solder mask covering at least a portion of said top elements.

10. The LED package of claim 1, further comprising a protective layer between the edge of said lens and the edge of said top surface, covering said top surface and said top elements.

11. An LED package, comprising:

a submount having a top and bottom surface;

an attach pad on said top surface;

a first contact pad on said top surface and integral to said attach pad;

a second contact pad on said top surface;

an LED mounted to said attach pad, an electrical signal applied to said first and second contact pads causing said LED to emit light, wherein said pads comprise thermally conductive layers covering most of said top surface to spread heat from said LED to the majority of said top surface; and

an optical element formed directly over said LED.

12. The LED package of claim 11, further comprising a metalized area covering a portion of said bottom surface, not in electrical contact with said top pads and conducting heat from said submount.

13. The LED package of claim 11, further comprising first and second surface mount contacts on said bottom surface and in electrical contact with said first and second mounting pads, respectively.

14. An LED package, comprising:

a submount having a top and bottom surface, with an LED mounted on said top surface;

a lens formed directly on said LED and a portion of said top surface;

a top heat spreading element on said top surface to spread heat from said LED across the majority of said top surface, said top spreading element extending radially on said top surface from said LED toward the edges of said submount; and

a bottom heat conducting element on said bottom surface to conduct heat from said submount.

15. A method for fabricating LED packages, comprising:

providing a submount panel sized to be separated into a plurality of LED package submounts;

forming top conductive elements on one surface of said submount panel for a plurality of LED packages;

attaching LEDs to said top elements, said LEDs electrically connected to said top conductive elements;

molding lenses over said LEDs; and

singulating said substrate panel to separate it into a plurality of LED packages.

16. The method of claim 15, further comprising wire bonds connecting said attached LEDs to one of said top conductive elements.

17. The method of claim 15, further comprising forming a thermally conductive metalized layer on a surface of said submount panel opposite said top conductive elements.

18. The method of claim 15 further comprising forming surface mount pads on said submount panel opposite said conductive elements and below said conductive elements, and forming vias through said submount panel, said vias electrically connecting said mount pads to said conductive elements.

19. The method of claim 15, further comprising coating said LEDs with a conversion material.

20. The method of claim 15, wherein said molding process comprises compression molding.

21. The method of claim 15, wherein said singulating comprises saw singulating.

22. A method for fabricating a plurality of surface mount LED packages, comprising:

providing a submount panel sized to accommodate formation of a plurality of LED packages;

forming sets of attach pads and contact pads on one surface of said submount panel, with each of said sets corresponding to one of said LED packages formed from said submount panel;

attaching a plurality of LEDs to said submount panel, each of said LEDs attached to and electrically connected to one of said sets of attach pads and contact pads;

molding a plurality of lenses on said submount panel, each of said lenses over one of said LEDs;

forming sets of surface mount contacts on the surface of said submount panel opposite said sets of attach pads and contact pads, each of said sets of said surface mount contacts corresponding to a respective one of said sets of attach pads and contact pads; and

singulating said substrate panel to separate it into a plurality of LED packages.

23. The method of claim 22, further comprising wire bonding said LED its respective one of said sets of attach pads and contact pads.

24. The method of claim 22, further comprising forming a plurality of thermally conductive metalized layers on the surface of said submount panel opposite said sets of attach pads and contact pads, each of said metalized layers corresponding to one of said sets of attach pads and contact pads.

25. The method of claim 22, further comprising, forming sets of vias through said submount panel, each of said vias sets corresponding to one of said sets of attach pads and contact pads, said vias electrically connecting its corresponding contact pads to its said surface mount pads.