Method of fabricating a light emitting diode chip having phosphor coating layer

• US 8,030,105 B1
• Filed: 03/23/2010
• Issued: 10/04/2011
• Est. Priority Date: 03/18/2010
• Status: Expired due to Fees

• Current Assignee: Everlight Electronics Company Limited
• Original Assignee: Everlight Electronics Company Limited
• Inventors: Hsieh, Chung-Chuan
• Primary Examiner(s): SARKAR, ASOK K
• Application Number:
  US12/729,721
• Publication Number:
  US 20110229993A1
• Time in Patent Office: 560 Days
• Field of Search: 257/E21.499, 438/29
• US Class Current: 438/29
• CPC Class Codes: H01L 2224/48091 Arched
• 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 2933/0041 relating to wavelength conversion elements
• CPC Class Codes: H01L 33/508 having a non-uniform spatial arrangement or non-uniform concentration, e.g. patterned wavelength conversion layer, wavelength conversion layer with a concentration gradient of the wavelength conversion material

Abstract

A method of fabricating light emitting diode chips having a phosphor coating layer comprises providing a substrate having a plurality of light emitting diodes formed thereon; forming a conductive bump on at least one of the plurality of light emitting diodes; forming a phosphor coating layer over the substrate and the light emitting diodes; cutting the phosphor coating layer by a point cutter to remove an upper portion of the phosphor coating layer, so as to reduce a thickness of the phosphor coating layer and expose the conductive bump; and forming a plurality of individual light emitting diode chips having the phosphor coating layer by separating the plurality of light emitting diodes.

Claims

1. A method of fabricating a plurality of light emitting diode chips having a phosphor coating layer, comprising:

providing a substrate having a plurality of light emitting diodes formed thereon;

forming a conductive bump on at least one of the plurality of light emitting diodes;

forming the phosphor coating layer over the substrate and the light emitting diodes;

cutting the phosphor coating layer with a point cutter to remove an upper portion of the phosphor coating layer, so as to reduce a thickness of the phosphor coating layer and expose the conductive bump, the cutting comprising;

rotating the point cutter about a rotation axis in a vertical direction; and

moving the substrate relative to the point cutter in a horizontal direction; and

forming a plurality of individual light emitting diode chips having the phosphor coating layer by separating the plurality of light emitting diodes.

2. The method of claim 1, wherein the point cutter is a diamond cutter or a Tungsten Carbide(WC) cutter.

3. The method of claim 1, wherein the point cutter cuts the upper portion of the phosphor coating layer in a horizontal direction.

4. The method of claim 1, further comprising cutting an upper portion of the conductive bump by the point cutter.

5. The method of claim 4, wherein, after cutting, an upper surface of the phosphor coating layer is substantially at the same level as an upper surface of the conductive bump.

6. The method of claim 1, wherein cutting the phosphor coating layer comprises:

cutting the phosphor coating layer to remove a surface layer of the phosphor coating layer;

checking whether the conductive bump is exposed; and

if the conductive bump is not exposed, repeating the cutting step until the conductive bump is exposed.

7. The method of claim 1, wherein the phosphor coating layer is formed by one of transfer molding, compressing molding, screen printing, spin coating, dispensing, electrophoresis and spray coating.

8. The method of claim 1, wherein forming the plurality of individual light emitting diode chips having the phosphor coating layer comprises dicing the phosphor coating layer, the light emitting diodes, and the substrate.

9. The method of claim 8, wherein the step of dicing is performed by a blade or a laser.

10. The method of claim 8, wherein the step of dicing further comprises:

dicing the phosphor coating layer and the light emitting diodes with a blade, and

dicing the substrate with a laser.

11. The method of claim 1, wherein:

the plurality of light emitting diodes comprises a plurality of light emitting diode dies formed separately on the substrate, and

wherein the step of forming the phosphor coating layer further comprises filling a space between the dies.

12. The method of claim 11, wherein forming the plurality of individual light emitting diode chips having the phosphor coating layer comprises dicing the phosphor coating layer and the substrate.

13. The method of claim 12, wherein the step of dicing is performed by a blade or laser.

14. The method of claim 13, wherein the step of dicing further comprises:

dicing the phosphor coating layer and the light emitting diodes with a blade, and

dicing the substrate with a laser.

15. The method of claim 11, wherein the substrate is a printed circuit board, a ceramic substrate, a silicon substrate, or a metal substrate.

16. The method of claim 1, wherein the step of cutting results in an upper surface of the phosphor coating layer having a rough surface with regular patterns.

17. The method of claim 1, wherein the step of cutting results in the phosphor coating layer having a substantially uniform thickness.

18. The method of claim 1, wherein the step of forming the phosphor coating layer further comprises mixing at least a phosphor powder and a resin,

the resin being a silicone or an epoxy.

19. The method of claim 1, wherein the step of forming the conductive bump further comprises forming the conductive bump from Au or alloy of Au.

20. The method of claim 1, wherein the substrate is a SiC substrate, a Si substrate, a sapphire substrate, a ZnO substrate, a GaAs substrate, a spinel substrate, or a metal substrate.