Light emitting diodes and a method of packaging the same
Disclosed herein is a method of assembling an array of light emitting diode (LED) dies on a substrate comprising: positioning dies in fluid; exposing the dies to a magnetic force to attract the dies onto magnets that are arranged at pre-determined locations either on or near the substrate; and forming permanent connections between the dies and the substrate thereby constituting an array of LED dies on a substrate.
1. A method of assembling an array of light emitting diode (LED) dies on a substrate comprising:
positioning dies in fluid;
exposing the dies to a magnetic force to attract the dies onto a front side of a substrate using magnets that are arranged at pre-determined locations either directly on the backside of the substrate or near the backside of the substrate; and
forming permanent electrical and/or mechanical connections between the dies and the substrate thereby constituting an array of LED dies on a substrate,
wherein prior to the positioning, the method comprises forming a buoyant layer on one side of each of the dies.
2. The method of claim 1 , wherein prior to the positioning, the method comprises forming a magnetic layer on another side of each of the dies.
3. The method of claim 1 , wherein after the positioning, the method further comprises temporarily sinking the dies using another magnetic force and then deactivating the magnetic force so that the dies rise to a top surface of the fluid with the buoyant layer facing in an upward direction.
4. The method of claim 1 , wherein the method further comprises dissolving the buoyant layer.
5. The method of claim 1 further comprising advancing the substrate with respect to the fluid to continuously expose the dies to magnetic forces and continuously attract the dies onto respective ones of the magnets that are arranged at pre-determined locations either directly on the backside of the substrate or near the backside of the substrate.
6. The method of claim 1 , wherein the forming comprises exposing the dies and the substrate to an elevated temperature to cause solder on a surface of the dies to adhere to the substrate.