Light emitting die (LED) packages and related methods

• US 10,256,385 B2
• Filed: 07/20/2011
• Issued: 04/09/2019
• Est. Priority Date: 10/31/2007
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Britt, Jeffrey Carl, Stanton, Brandon, Fu, Yankun
• Primary Examiner(s): Malsawma, Lex
• Assistant Examiner(s): Jones, Eric W
• Application Number:
  US13/187,232
• Publication Number:
  US 20120187862A1
• Time in Patent Office: 2,820 Days
• Field of Search: 257 98, 257 79, 438 22, 438 25, 438 46
• CPC Class Codes: H01L 2224/29144 Gold [Au] as principal constituent
• CPC Class Codes: H01L 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• 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 2224/48647 Copper (Cu) as principal constituent
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2224/83024 Applying flux to the bonding area
• CPC Class Codes: H01L 2224/83097 Heating
• CPC Class Codes: H01L 2224/83191 wherein the layer connectors are disposed only on the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/83205 Ultrasonic bonding
• CPC Class Codes: H01L 2224/83447 Copper [Cu] as principal constituent
• CPC Class Codes: H01L 2224/8349 with a principal constituent of the material being a polymer, e.g. polyester, phenolic based polymer, epoxy
• CPC Class Codes: H01L 2224/83805 involving forming a eutectic alloy at the bonding interface
• CPC Class Codes: H01L 2224/83815 Reflow soldering
• CPC Class Codes: H01L 2224/83912 Mechanical cleaning, e.g. abrasion using hydro blasting, brushes, ultrasonic cleaning, dry ice blasting, gas-flow
• CPC Class Codes: H01L 2224/85447 Copper (Cu) as principal constituent
• CPC Class Codes: H01L 2224/92247 the second connecting process involving a wire connector
• CPC Class Codes: H01L 24/29 of an individual layer connector
• CPC Class Codes: H01L 24/32 of an individual layer connector
• CPC Class Codes: H01L 24/45 : of an individual wire connector
• CPC Class Codes: H01L 24/48 : of an individual wire connector
• CPC Class Codes: H01L 24/73 : Means for bonding being of different types provided for in two or more of groups H01L24/10, H01L24/18, H01L24/26, H01L24/34, H01L24/42, H01L24/50, H01L24/63, H01L24/71
• CPC Class Codes: H01L 24/83 : using a layer connector
• CPC Class Codes: H01L 24/85 : using a wire connector wire bonding in general B23K20/004
• CPC Class Codes: H01L 24/92 : Specific sequence of method steps
• 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 2924/00011 : Not relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• 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 2924/01013 : Aluminum [Al]
• CPC Class Codes: H01L 2924/01014 : Silicon [Si]
• CPC Class Codes: H01L 2924/01028 : Nickel [Ni]
• CPC Class Codes: H01L 2924/0105 : Tin [Sn]
• CPC Class Codes: H01L 2924/01087 : Francium [Fr]
• CPC Class Codes: H01L 2924/01322 : Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases
• CPC Class Codes: H01L 2924/12032 : Schottky diode
• CPC Class Codes: H01L 2924/12041 : LED
• 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
• CPC Class Codes: H01L 33/642 : characterized by the shape
• CPC Class Codes: H01L 33/647 : the elements conducting electric current to or from the semiconductor body

Abstract

LED packages and related methods are provided. The LED packages can include a submount having a top and bottom surface and a plurality of top electrically conductive elements on the top surface of the submount. An LED can be disposed on one of the top electrically conductive elements. The LED can emit a dominant wavelength generally between approximately 600 nm and approximately 650 nm, and more particularly between approximately 610 nm and approximately 630 nm when an electrical signal is applied to the top electrically conductive elements. A bottom thermally conductive element can be provided on the bottom surface and is not in electrical contact with the top electrically conductive elements. A lens can be disposed over the LED. The LED packages can have improved lumen performances, lower thermal resistances, improved efficiencies, and longer operational lifetimes.

Claims

1. A light-emitting die (LED) package comprising:

a ceramic submount comprising a top surface, a bottom surface, and a plurality of side edges;

a bottom thermally conductive element disposed on the bottom surface of the submount for conducting heat from the submount;

an LED having a multi-quantum well and disposed on the submount, the LED operable for emitting a dominant wavelength between approximately 610 nm and approximately 630 nm, the LED having a luminous flux that is approximately 100 lm or greater, such that a minimum luminous flux to footprint ratio for the LED package is greater than approximately 5.8 lm/mm² of a footprint of the LED package when an electrical signal comprises a current of approximately 350 mA;

a flux eutectic LED die attachment attaching the LED to the submount;

a lens molded over the LED and the submount; and

a protective layer substantially disposed over the top surface of the ceramic submount between the ceramic submount and the lens;

wherein a polarity of the LED is such that an N-cladding of the LED is below the multi-quantum well and a P-cladding of the LED is above the multi-quantum well; and

wherein each of the plurality of side edges of the ceramic submount is substantially flush with a corresponding side edge of the protective layer,

wherein the LED package generates a light output of approximately 120 lumens/watt or greater.

2. The LED package of claim 1, wherein the submount comprises aluminum nitride.

3. The LED package of claim 1, wherein the LED package is configured to generate a light output of approximately 130 lumens/watt or greater.

4. The LED package of claim 1, wherein the LED package is configured to have a predicted L70 lifetime of at least 50,000 hours or greater at 350 milliamps and 85°

C.

5. The LED package of claim 1, wherein the lens is of a radius size of approximately 1.275 mm or greater.

6. The LED package of claim 1 wherein the LED package comprises:

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

the LED disposed on at least one of the top electrically conductive elements.

7. The LED package of claim 6, wherein the submount comprises aluminum nitride.

8. The LED package of claim 1, wherein the protective layer is substantially disposed over an entirety of the top surface of the ceramic submount between the ceramic submount and the lens.

9. A light-emitting die (LED) package comprising:

a ceramic submount comprising a top surface, a bottom surface, and a plurality of side edges;

a bottom thermally conductive element disposed on the bottom surface of the submount for conducting heat from the submount;

an LED having a multi-quantum well and disposed on the submount, the LED operable for emitting a dominant wavelength between approximately 610 nm and approximately 630 nm, the LED having a luminous flux that is approximately 100 lm or greater, such that a minimum luminous flux to footprint ratio for the LED package is greater than approximately 5.8 lm/mm² of a footprint of the LED package when an electrical signal comprises a current of approximately 350 mA;

a flux eutectic LED die attachment attaching the LED to the submount;

a lens molded over the LED and the submount; and

a protective layer substantially disposed over the top surface of the ceramic submount between the ceramic submount and the lens;

wherein a polarity of the LED is such that an N-cladding of the LED is below the multi-quantum well and a P-cladding of the LED is above the multi-quantum well; and

wherein each of the plurality of side edges of the ceramic submount is substantially flush with a corresponding side edge of the protective layer,

wherein the LED package generates a light output of approximately 120 lumens/watt or greater.

10. The LED package of claim 9, wherein the submount comprises aluminum nitride.

11. The LED package of claim 9, wherein the LED package is configured to generate a light output of approximately 130 lumens per watt or greater.

12. The LED package of claim 9, wherein the LED package is configured to have a predicted L70 lifetime of at least 50,000 hours or greater at 350 milliamps and 85°

C.

13. The LED package of claim 9, wherein the lens is of a radius size of approximately 1.275 mm or greater.

14. The LED package of claim 9 wherein the LED package comprises:

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

the LED disposed on one of the top electrically conductive elements.

15. The LED package of claim 14, wherein the submount comprises aluminum nitride.

16. A light-emitting die (LED) package comprising:

a submount comprising aluminum nitride comprising a top surface, a bottom surface, and a plurality of side edges;

a bottom thermally conductive element disposed on the bottom surface of the submount for conducting heat from the submount;

an LED having a multi-quantum well and disposed on the submount, the LED operable for emitting a dominant wavelength between approximately 610 nm and approximately 630 nm, the LED having a luminous flux that is approximately 100 lm or greater, such that a minimum luminous flux to footprint ratio for the LED package is greater than approximately 5.8 lm/mm² of a footprint of the LED package when an electrical signal comprises a current of approximately 350 mA;

a flux eutectic LED die attachment attaching the LED to the submount;

a lens molded over the LED and the submount; and

a protective layer substantially disposed over the top surface of the submount between the submount and the lens;

wherein a polarity of the LED is such that an N-cladding of the LED is below the multi-quantum well and a P-cladding of the LED is above the multi-quantum well; and

wherein each of the plurality of side edges of the ceramic submount is substantially flush with a corresponding side edge of the protective layer,

wherein the LED package generates a light output of approximately 120 lumens/watt or greater.

17. A method of operating a light-emitting die (LED) package comprising:

providing an LED package comprising;

a ceramic submount comprising a top surface, a bottom surface, and a plurality of side edges;

a bottom thermally conductive element disposed on the bottom surface of the submount for conducting heat from the submount;

an LED disposed on the submount, the LED having a multi-quantum well with a polarity such that an N-cladding of the LED is below the multi-quantum well and a P-cladding of the LED is above the multi-quantum well, the LED operable for emitting a dominant wavelength between approximately 610 nm and approximately 630 nm, the LED having a luminous flux that is approximately 100 lm or greater, such that a minimum luminous flux to footprint ratio for the LED package is greater than approximately 5.8 lm/mm² of a footprint of the LED package when an electrical signal comprises a current of approximately 350 mA;

a flux eutectic LED die attachment attaching the LED to the submount;

a lens molded over the LED and the submount;

wherein each of the plurality of side edges of the ceramic submount is substantially flush with a corresponding side edge of the protective layer;

applying an electrical signal to the LED package; and

generating a light output from the LED in the LED package that is approximately 120 lumens per watts or greater.

18. The method of claim 17, wherein the LED package is configured to have a predicted L70 lifetime of at least 50,000 hours or greater at 350 milliamps and 85°

C.

19. A light-emitting die (LED) package comprising:

a submount comprising a top surface, a bottom surface, and a plurality of side edges;

a bottom thermally conductive element disposed on the bottom surface of the submount for conducting heat from the submount;

an LED having a multi-quantum well and disposed on the submount, the LED operable for emitting a dominant wavelength between approximately 610 nm and approximately 630 nm, the LED having a luminous flux that is approximately 100 lm or greater, such that a minimum luminous flux to footprint ratio for the LED package is greater than approximately 5.8 lm/mm² of a footprint of the LED package when an electrical signal comprises a current of approximately 350 mA;

a flux eutectic LED die attachment attaching the LED to the submount;

a lens molded over the LED and the submount; and

a protective layer substantially disposed over the top surface of the submount between the submount and the lens;

wherein a polarity of the LED is such that an N-cladding of the LED is below the multi-quantum well and a P-cladding of the LED is above the multi-quantum well; and

wherein each of the plurality of side edges of the ceramic submount is substantially flush with at least one corresponding side edge of the protective layer,

wherein the LED package generates a light output of approximately 120 lumens/watt or greater.