Wafer level reflector for LED packaging
View Patent ↗An optical emitter is fabricated by bonding a Light-Emitting Diode (LED) die to a package wafer, electrically connecting the LED die and the package wafer, forming a phosphor coating over the LED die on the package wafer, molding a lens over the LED die on the package wafer, molding a reflector on the package wafer, and dicing the wafer into at least one optical emitter.
1. A method of wafer level packaging of an optical emitter, comprising:
bonding a Light-Emitting Diode (LED) die to a packaging wafer;
electrically connecting the LED die and the packaging wafer;
forming a phosphor coating over the LED die on the packaging wafer;
molding a lens over the LED die on the packaging wafer;
molding a reflector on the packaging wafer; and
dicing the packaging wafer into at least one optical emitter, and
wherein the lens and the reflector are molded at the same time.
2. A method of wafer level packaging of an optical emitter, comprising:
bonding a Light-Emitting Diode (LED) die to a packaging wafer;
electrically connecting the LED die and the packaging wafer;
forming a phosphor coating over the LED die on the packaging wafer;
molding a lens over the LED die on the packaging wafer;
molding a reflector on the packaging wafer; and
dicing the packaging wafer into at least one optical emitter, and
wherein the molding the reflector on the packaging wafer occurs before bonding an LED die to a packaging wafer.
3. The method of claim 2 , further comprising patterning a photoresist layer over a metal portion of a top surface of the packaging wafer before the molding a reflector on the packaging wafer and before bonding the LED die to the packaging wafer.
4. The method of claim 3 , wherein the metal portion of a top surface of the packaging wafer is electrically connected to a metal pad on a back surface of the packaging wafer.
5. The method of claim 3 , wherein the molding a reflector on the packaging wafer comprises applying pressure to a dispensed reflector precursor through a compression mold to shape the reflector precursor, setting the reflector precursor, and removing the compression mold.
6. The method of claim 5 , further comprising removing the photoresist layer after molding the reflector.
7. The method of claim 1 , further comprising bonding a Zener diode die on the packaging wafer.
8. The method of claim 7 , wherein the molding a reflector on the packaging wafer occurs after bonding the LED die and the Zener diode die, wherein the reflector is molded over the Zener diode die.
9. The method of claim 1 , further comprising applying an oxygen plasma.
10. The method of claim 1 , wherein the reflector is white silicone comprising a metal oxide and silicone.
11. The method of claim 1 , wherein the molding a reflector on the packaging wafer comprises injecting a reflector precursor into a injection mold to shape the reflector precursor, setting the reflector precursor, and removing the injection mold.
12. The method of claim 11 , wherein setting the reflector precursor comprises curing the reflector precursor for a setting duration.
13. A method comprising:
receiving a package wafer having a plurality of LED dies attached to one side of the package wafer and electrical connections connecting each of the plurality of LED dies and the package wafer;
attaching a plurality of molded lenses to the package wafer on each of the plurality of LED dies; and
attaching a plurality of molded reflectors to the package wafer, each of the plurality of molded reflectors surrounding each of the plurality of LED dies;
wherein the molded reflectors are angled to redirect LED side emissions toward a direction away from the package wafer.
14. The method of claim 13 , wherein the package wafer further includes a plurality of Zener diode dies, each of the plurality of Zener diode dies disposed under each of the plurality of molded reflectors.
15. The method of claim 13 , wherein each of the plurality of molded lenses completely fills an interior space of each of the plurality of reflectors.
16. The method of claim 13 , wherein each of the plurality of molded lenses is a portion of an ellipsoid.
17. The method of claim 13 , wherein a top surface of each of the plurality of molded lenses is flat.
18. The method of claim 13 , wherein the package wafer is a silicon wafer.
19. The method of claim 13 , further comprising patterning a photoresist layer over a metal portion of a top surface of the packaging wafer before attaching the plurality of molded reflectors to the package wafer.
20. The method of claim 2 , further comprising applying an oxygen plasma prior to molding the lens over the LED die on the packaging wafer.