Wavelength converting light-emitting devices and methods of making the same
Wavelength converting light-emitting devices and methods of making the same are provided. In some embodiments, the devices include a phosphor material region designed to convert the wavelength of emitted light.
1. A method of making a wavelength converting LED die, the method comprising:
providing an LED die having a light-emitting surface and at least one electrically conductive bond pad disposed on the light-emitting surface;
disposing a mask layer over the light-emitting surface, wherein the mask layer exposes a portion of the light-emitting surface and covers the bond pad;
disposing a wavelength converting layer over the mask layer and the portion exposed by the mask layer of the light-emitting surface; and
lifting-off the mask layer so as to also remove the wavelength converting layer disposed over the mask layer including the mask layer covering the bond pad to expose the bond pad, while leaving the wavelength converting layer disposed over the exposed portion of the light-emitting surface.
2. The method of claim 1 , wherein the wavelength converting LED die is configured to emit substantially white light.
3. The method of claim 1 , wherein the wavelength converting layer comprises a wavelength converting material and a second material.
4. The method of claim 3 , wherein the second material comprises a spin-on-glass.
5. The method of claim 1 , wherein the wavelength converting material comprises one or more phosphors.
6. The method of claim 1 , wherein providing the LED die having the light-emitting surface comprises providing a wafer including a plurality of LED die, each LED die having a light-emitting surface.
7. The method of claim 6 , wherein disposing the mask layer comprises disposing the mask layer over the wafer.
8. The method of claim 6 , wherein disposing the wavelength converting layer comprises disposing the wavelength converting material over the wafer.
9. The method of claim 1 , wherein disposing the wavelength converting layer comprises a technique selected from the group consisting of spin coating, screen printing or spray coating.
10. The method of claim 1 , wherein the wavelength converting layer has an average thickness and a thickness uniformity of less than 30% the average thickness.
11. The method of claim 1 , further comprising disposing a second wavelength converting layer over the first wavelength converting layer.
12. The method of claim 1 , wherein disposing the wavelength converting layer comprises spin coating the wavelength converting layer.
13. The method of claim 12 , further comprising forming a second bond pad on the light-emitting surface.
14. The method of claim 1 , wherein the LED die has an edge and the wavelength converting layer is separated from the bond pad by a distance less than or equal to 0.005 times the length of the edge.
15. The method of claim 1 , wherein the LED die has an edge of at least 1 mm.
16. The method of claim 1 , further comprising disposing a mask layer over the light-emitting surface prior to spin coating a wavelength converting layer, wherein the mask layer exposes a portion of the light-emitting surface.
17. The method of claim 13 , wherein the wavelength converting layer has an average thickness and a thickness uniformity of less than 30% the average thickness.
18. The method of claim 13 , further comprising disposing a second wavelength converting layer over the first wavelength converting layer.
19. The method of claim 12 , wherein the LED die has a surface area of at least 1 mm 2 .
20. The method of claim 12 , wherein the wavelength converting layer comprises a phosphor and a spin-on glass.
21. The method of claim 20 , wherein the ratio of the phosphor to the spin-on glass is between 0.1-2 g/mL.