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

• US 8,309,378 B2
• Filed: 09/12/2011
• Issued: 11/13/2012
• 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:
  US13/229,994
• Publication Number:
  US 20120003758A1
• Time in Patent Office: 428 Days
• Field of Search: 257/E21.499, 438/29, 438/110, 438/113
• 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 substantially uniformly thick 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;

reducing a thickness of the phosphor coating layer for exposing the conductive bump; and

separating a plurality of individual light emitting chips by dicing the phosphor coating layer and the light emitting diodes with a blade, and dicing the substrate with a laser.

2. The method of claim 1, wherein reducing the thickness of the phosphor coating layer is performed by cutting the phosphor coating layer with a point cutter.

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

4. The method of claim 2, wherein the point cutter cuts the upper portion of the phosphor coating layer in a horizontal direction.

5. The method of claim 2, further comprising cutting an upper portion of the conductive bump by the point cutter.

6. The method of claim 5, 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.

7. The method of claim 2, 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.

8. The method of claim 2, wherein cutting the phosphor coating layer is performed by:

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.

9. The method of claim 2, wherein the step of cutting results in an upper surface of the phosphor coating layer having a rough surface with regular patterns.

10. 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.

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.