Deposition of phosphor on die top by stencil printing

• US 8,993,358 B2
• Filed: 12/28/2011
• Issued: 03/31/2015
• Est. Priority Date: 12/28/2011
• Status: Active Grant

• Current Assignee: Ledengin, Inc. (Ams-Osram AG)
• Original Assignee: Ledengin, Inc. (Ams-Osram AG)
• Inventors: Mei, Zequn, Yan, Xiantao
• Primary Examiner(s): Sun, Yu-Hsi D
• Assistant Examiner(s): Bell, Lauren R
• Application Number:
  US13/338,912
• Publication Number:
  US 20130168703A1
• Time in Patent Office: 1,189 Days
• Field of Search: 257/88, 257/E21.032, 438/22, 438/26, 438/28, 438/33, 438/29, 438/82, 438/99
• US Class Current: 438/28
• CPC Class Codes: H01L 2933/0041 relating to wavelength conversion elements
• CPC Class Codes: H01L 33/50 Wavelength conversion elements

Abstract

A method for depositing a layer of phosphor-containing material on a plurality of LED dies includes disposing a template with a plurality of openings on an adhesive tape and disposing each of a plurality of LED dies in one of the plurality of openings of the template. The method also includes disposing a stencil over the template and the plurality of LED dies. The stencil has a plurality of openings configured to expose a top surface of each of the LED dies. Next, a phosphor-containing material is disposed on the exposed top surface of each the LED dies. The method further includes removing the stencil and the template.

Claims

1. A method for depositing a layer of phosphor-containing material on a plurality of LED (light-emitting diode) dies, the method comprising:

disposing a template with a plurality of openings on an adhesive tape;

after disposing the template on the adhesive tape, disposing each of the plurality of LED dies directly on the adhesive tape through a respective one of the plurality of openings of the template;

after disposing the LED dies on the adhesive tape, disposing a stencil over the template and the plurality of LED dies, the stencil having a plurality of openings configured to expose a top surface of each of the LED dies;

after disposing the stencil, depositing the phosphor-containing material on the exposed top surface of each of the LED dies;

after depositing the phosphor-containing material, removing the stencil; and

removing the template from the adhesive tape.

2. The method of claim 1, wherein the adhesive tape is placed on a glass plate.

3. The method of claim 1, wherein the adhesive tape is a heat release tape.

4. The method of claim 1, wherein the adhesive tape is a UV release tape.

5. The method of claim 1, wherein an area of one of the openings in the template is approximately equal to the size of a respective one of the LED dies.

6. The method of claim 1, wherein a thickness of one of the openings in the template is substantially equal to a thickness of a respective one of the LED dies.

7. The method of claim 1, wherein the stencil is configured to cover bond pad areas on each of the LED dies.

8. The method of claim 1, wherein a depth of each of the openings in the stencil is equal to a desired thickness of the phosphor-containing material.

9. The method of claim 1, wherein the stencil is coated with Polytetrafluoroethylene (PTFE) under the trademark of TEFLON®

.

10. The method of claim 1, wherein the stencil is made of metal.

11. The method of claim 1, wherein the stencil is made of an insulator material.

12. A method for depositing a layer of phosphor-containing material on a plurality of LED (light-emitting diode) dies, the method comprising:

disposing a template with a plurality of openings on an adhesive tape;

after disposing the template on the adhesive tape, disposing each of the plurality of LED dies directly on the adhesive tape through a respective one of the plurality of openings of the template;

after disposing the LED dies on the adhesive tape, disposing a metal stencil over the template and the plurality of LED dies, the stencil having a plurality of openings configured to expose a top surface of each of the LED dies;

after disposing the stencil, depositing the phosphor-containing material on the exposed top surface of each of the LED dies;

after depositing the phosphor-containing material, removing the metal stencil; and

removing the template.