Wafer-level chip scale packaging for LED comprising carrier substrate with thermally conductive through holes and fill channels

• US 8,049,330 B2
• Filed: 11/23/2005
• Issued: 11/01/2011
• Est. Priority Date: 06/14/2005
• Status: Expired due to Fees

• Current Assignee: Industrial Technology Research Institute
• Original Assignee: Industrial Technology Research Institute
• Inventors: Tain, Ra-Min, Lo, Wei-Chung, Shen, Li-Cheng
• Primary Examiner(s): Gebremariam, Samuel
• Assistant Examiner(s): Arena, Andrew O
• Application Number:
  US11/284,936
• Publication Number:
  US 20060278885A1
• Time in Patent Office: 2,169 Days
• Field of Search: 257/713, 257/E23.101, 257/E23.105, 257/99, 257/712, 257/720, 257/E23.106, 257/E23.108, 257/E23.109
• US Class Current: 257/720
• CPC Class Codes: H01L 2224/0554 External layer
• CPC Class Codes: H01L 2224/0555 Shape
• CPC Class Codes: H01L 2224/0556 Disposition
• 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 2224/16 of an individual bump connector
• CPC Class Codes: H01L 2224/48091 Arched
• 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 2924/12041 LED
• CPC Class Codes: H01L 33/486 adapted for surface mounting
• 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 33/641 characterized by the materials
• CPC Class Codes: H01L 33/642 characterized by the shape

Abstract

A structure of light emitting diode (LED) wafer-level chip scale packaging (WL-CSP) is disclosed. The process of making the same is also provided in this invention. The LED CSP utilizes the through hole metal filling to enhance heat conduction between the LED die and its carrier substrate. The CSP structure is achieved by bonding pre-processed through-hole-filling carrier substrate against the flip-chip LED wafer.

Claims

1. A light emitting diode (LED) wafer-level chip scale packaging, comprising:

an LED with a positive electrode and a negative electrode disposed on one side thereof;

a carrier substrate having a plurality of through holes, which are filled with an electrically and thermally conductive material,

wherein the positive electrode and the negative electrode of said LED are attached to a first surface of said carrier substrate,

wherein the positive electrode is electrically and thermally connected to a first one of said through holes and the negative electrode is electrically and thermally connected to a second one of said through holes;

a thermally conductive area filled with a thermally conductive dielectric material, which is confined in an area surrounded by said LED and said carrier substrate and is contacted with at least a third one of said filled through holes; and

at least one fill channel within said carrier substrate,

said fill channel contacting said thermally conductive area and filled with said thermally conductive dielectric material.

2. The LED wafer-level chip scale packaging according to claim 1, further comprising at least two solder balls, which are respectively disposed between the LED'"'"'s positive electrode and the carrier substrate, and between the LED'"'"'s negative electrode and the carrier substrate, so that said LED is attached to said carrier substrate.

3. The LED wafer-level chip scale packaging according to claim 1, further comprising a void space which is confined by said LED and said carrier substrate.

4. The LED wafer-level chip scale packaging according to claim 1, further comprising at least one package-to-board connection coupled to a second surface of said carrier substrate and contacted with the filled through hole, thereby heat generated from said LED is conducted to said package-to-board connection by way of the filled through hole.

5. The LED wafer-level chip scale packaging according to claim 4, wherein said package-to-board connection comprises a bump, a pin, silver paste, or solder paste.

6. The LED wafer-level chip scale packaging according to claim 4, further comprising at least one positive power channel and at least one negative power channel within said carrier substrate, one end of the positive power channel and the negative power channel being respectively electrically connected to the positive electrode and the negative electrode of said LED, and other end of the positive power channel and the negative power channel being respectively connected to the package-to-board connection, wherein the positive power channel and the negative power channel are filled with electrically conductive material, thereby the positive electrode and the negative electrode of said LED is electrically connected to the package-to-board connection.

7. The LED wafer-level chip scale packaging according to claim 1, wherein said at least one through hole is arranged in columns.

8. The LED wafer-level chip scale packaging according to claim 1, wherein said at least one through hole is arranged in blocks.

9. A method for light emitting diode (LED) wafer-level chip scale packaging, comprising:

providing a carrier substrate and an LED,

said LED having a positive electrode and a negative electrode disposed on one side thereof;

forming a plurality of through holes in said carrier substrate, said through holes passing through between a first surface and a second surface of said carrier substrate;

filling the through holes with an electrically and thermally conductive material;

forming at least one fill channel in said carrier substrate;

attaching the positive electrode and the negative electrode of said LED to the first surface of said carrier substrate,

wherein the positive electrode is electrically and thermally connected to a first one of said through holes and the negative electrode is electrically and thermally connected to a second one of said through holes;

injecting thermally conductive dielectric material from said second surface into an area surrounded by said LED and said carrier substrate by way of the fill channel, such that said thermally conductive dielectric material is contacted with at least a third one of said through holes.

10. The method according to claim 9, after said LED is attached to said carrier substrate, further comprising injecting thermally conductive material into an area surrounded by said LED and said carrier substrate by the way of the fill channel.

11. The method according to claim 9, before said LED is attached to said carrier substrate, further comprising applying thermally conductive material on the first surface of said carrier substrate.

12. The method according to claim 9, after said LED is attached to said carrier substrate, further comprising performing underfill to fill thermally conductive material into an area surrounded by said LED and carrier substrate.

13. The method according to claim 9, further comprising forming a void space which is confined by said LED and said carrier substrate.

14. The method according to claim 9, wherein said step of attaching the LED and the carrier substrate is achieved by forming at least two solder balls, which are respectively disposed between the LED'"'"'s positive electrode and the carrier substrate, and between the LED'"'"'s negative electrode and the carrier substrate, so that said LED is attached to said carrier substrate.

15. The method according to claim 9, further comprising coupling at least one package-to-board connection to the second surface of said carrier substrate, said package-to-board connection contacting with the filled through hole.

16. The method according to claim 15, wherein said package-to-board connection comprises a bump, a pin, silver paste, or solder paste.

17. The method according to claim 15, further comprising forming at least one positive power channel and at least one negative power channel within said carrier substrate, one end of the positive power channel and the negative power channel being respectively electrically connected to the positive electrode and the negative electrode of said LED, and other end of the positive power channel and the negative power channel being respectively connected to the package-to-board connection, wherein the positive power channel and the negative power channel are filled with electrically conductive material, thereby the positive electrode and the negative electrode of said LED is electrically connected to the package-to-board connection.

18. A light emitting diode (LED) device, comprising:

at least one LED wafer-level chip scale packaging, each comprising;

an LED with a positive electrode and a negative electrode disposed on one side thereof;

a carrier substrate a plurality of through holes, which are filled with an electrically and thermally conductive material,

wherein the positive electrode and the negative electrode of said LED are attached to a first surface of said carrier substrate,

wherein the positive electrode is electrically and thermally connected to a first one of said through holes and the negative electrode is electrically and thermally connected to a second one of said through holes, and

at least one package-to-board connection coupled to a second surface of said carrier substrate and contacted with the filled through hole,

thereby heat generated from said LED is conducted to said package-to-board connection by way of the filled through holes;

a board bonded to said LED wafer-level chip scale packaging through the package-to-board connection;

a thermally conductive area filled with a thermally conductive material, which is confined in an area surrounded by said LED and said carrier substrate, and is contacted with at least a third one of said filled through holes; and

at least one fill channel within said carrier substrate,

said fill channel contacting said thermally conductive area and filled with said thermally conductive dielectric material.

19. The LED device according to claim 18, wherein said board comprises at least one via, which is filled with thermally conductive material therein, one end of said via being contacted with the package-to-board connection.

20. The LED device according to claim 19, further comprising a heat sink contacted with other end of said via.

21. The LED device according to claim 18, wherein said board is made of conductive material.

22. The LED device according to claim 18, further comprising at least two solder balls, which are respectively disposed between the LED'"'"'s positive electrode and the carrier substrate, and between the LED'"'"'s negative electrode and the carrier substrate, so that said LED is attached to said carrier substrate.

23. The LED device according to claim 18, further comprising a void space which is confined by said LED and said carrier substrate.

24. The LED device according to claim 18, wherein said package-to-board connection comprises a bump, a pin, silver paste, or solder paste.