A method of manufacturing a display device is disclosed. The method comprises aligning a first wafer with a donor substrate, the first wafer including a first light emitting diodes (LEDs), first alignment keys, and second alignment keys. The method comprises transferring the first LEDs and a portion of the second alignment keys included in the first wafer onto the donor substrate. The method comprises aligning a second wafer with the donor substrate, the second wafer including second LEDs, first alignment keys, second alignment keys, and third alignment keys of the second wafer. The second wafer is aligned with the donor substrate by aligning the portion of the second alignment keys of the first wafer that are disposed on the donor substrate with the third alignment keys of the second wafer.