Method of making white LED package structure having a silicon substrate

• US 8,172,632 B2
• Filed: 11/05/2009
• Issued: 05/08/2012
• Est. Priority Date: 02/08/2007
• Status: Expired due to Fees

• Current Assignee: Walsin Lihwa Corporation
• Original Assignee: TOUCH MICRO-SYSTEM TECHNOLOGY CORP. (Walsin Lihwa Corporation)
• Inventors: Lin, Hung-Yi, Chang, Hong-Da
• Primary Examiner(s): Ton, Toan
• Assistant Examiner(s): COUGHLIN, ANDREW J
• Application Number:
  US12/613,508
• Publication Number:
  US 20100047942A1
• Time in Patent Office: 915 Days
• Field of Search: 445 23- 25, 313/498
• US Class Current: 445/25
• CPC Class Codes: F21K 9/00 Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• 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 2924/00014 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 2924/10253 Silicon [Si]
• CPC Class Codes: H01L 33/50 Wavelength conversion elements

Abstract

A method of making a white LED package structure having a silicon substrate comprises providing a silicon substrate and performing an etching process to form a plurality of cup-structures on a top surface of the silicon substrate. Next, a reflective layer on the top surface of the silicon substrate is formed, and a transparent insulating layer on the reflective layer is formed. Subsequently, a plurality of blue LEDs are respectively bonded in each cup-structure, wherein the blue LEDs have various wavelengths. Last, a plurality of kinds of phosphor powders corresponding to the wavelengths of the blue LEDs are mixed with each other and added to a sealing material, and a sealing process is performed to form a phosphor structure on the cup-structures.

Claims

1. A method of making a white LED package structure having a silicon substrate comprising:

providing a silicon substrate, and performing an etching process to form a plurality of cup-structures on a top surface of the silicon substrate;

forming a reflective layer on the top surface of the silicon substrate;

forming a transparent insulating layer on the reflective layer;

forming a plurality of metal bumps on the transparent insulating layer respectively in each cup-structure, and forming a plurality of electrodes on the transparent insulating layer between the cup-structures;

respectively bonding a plurality of blue LEDs on each metal bump in each cup-structure, and electrically connecting respectively the blue LEDs to the electrodes, wherein the blue LEDs emit lights with different peak wavelengths; and

mixing a plurality of kinds of phosphor powders, the plurality of kinds of phosphor powders having different absorption spectra respectively corresponding to the different peak wavelengths of the lights emitted by the plurality of blue LEDs, and adding a sealing material, and then, performing a sealing process using the mixed phosphor powders and sealing material to form a phosphor structure on the plurality of cup-structures.

2. The method of claim 1, wherein each cup-structure has inclined sidewalls.

3. The method of claim 2, wherein the etching process making the inclined sidewalls of the cup-structures comprises a reactive ion etching process.

4. The method of claim 2, wherein the etching process making the inclined sidewalls of the cup-structures comprises a Bosch process.

5. The method of claim 2, wherein the etching process making the inclined sidewalls of the cup-structures comprises a wet etching process utilizing KOH solution as an etching solution.

6. The method of claim 2, wherein the etching process making the inclined sidewalls of the cup-structures comprises a wet etching process utilizing TMAH solution as an etching solution.

7. The method of claim 2, wherein the etching process making the inclined sidewalls of the cup-structures comprises a wet etching process utilizing EDP solution as an etching solution.

8. The method of claim 1, wherein the reflective layer is formed on the silicon substrate by sputtering, evaporation or chemical deposition.

9. The method of claim 1, wherein the transparent insulating layer is formed on the silicon substrate by sputtering, evaporation or chemical deposition.

10. The method of claim 1, wherein the metal bumps are formed on the transparent insulating layer by lift-off.

11. The method of claim 1, wherein the metal bumps are formed on the transparent insulating layer by electroplating.

12. The method of claim 1, wherein the blue LEDs are bonded on the metal bumps by die attachment using glass frit.

13. The method of claim 1, wherein the sealing process is a molding process.

14. The method of claim 1, wherein the sealing process is an encapsulating process.

15. A method of making a white LED package structure having a silicon substrate comprising:

providing a silicon substrate, and performing an etching process to form a plurality of cup-structures on a top surface of the silicon substrate;

forming a reflective layer on the top surface of the silicon substrate;

forming a transparent insulating layer on the reflective layer;

forming a conductive layer on the transparent insulating layer;

respectively bonding a plurality of blue LEDs on the conductive layer in each cup-structure, wherein the blue LEDs emit lights with different peak wavelengths; and

mixing a plurality of kinds of phosphor powders, the plurality of kinds of phosphor powders having different absorption spectra respectively corresponding to the different peak wavelengths of the lights emitted by the plurality of blue LEDs, and adding a sealing material, and then performing a sealing process using the mixed phosphor powders and sealing material to form a phosphor structure on the plurality of cup-structures.

16. The method of claim 15, wherein each cup-structure has inclined sidewalls.

17. The method of claim 16, wherein the etching process fabricating the inclined sidewalls of the cup-structures comprises a reactive ion etching process.

18. The method of claim 16, wherein the etching process fabricating the inclined sidewalls of the cup-structures comprises a Bosch process.

19. The method of claim 16, wherein the etching process fabricating the inclined sidewalls of the cup-structures comprises a wet etching process utilizing KOH solution as an etching solution.

20. The method of claim 16, wherein the etching process fabricating the inclined sidewalls of the cup-structures comprises a wet etching process utilizing TMAH solution as an etching solution.

21. The method of claim 16, wherein the etching process fabricating the inclined sidewalls of the cup-structures comprises a wet etching process utilizing EDP solution as an etching solution.

22. The method of claim 15, wherein the reflective layer is formed on the silicon substrate by sputtering, evaporation or chemical deposition.

23. The method of claim 15, wherein the transparent insulating layer is formed on the silicon substrate by sputtering, evaporation or chemical deposition.

24. The method of claim 15, wherein the conductive layer are formed on the transparent insulating layer by lift-off.

25. The method of claim 15, wherein the conductive layer are formed on the transparent insulating layer by electroplating.

26. The method of claim 15, wherein the blue LEDs are bonded on the conductive layer by flip chip attachment.

27. The method of claim 15, wherein the sealing process is a molding process.

28. The method of claim 15, wherein the sealing process is an encapsulating process.