a foreign substance removal device for removing foreign substance from a plurality of semiconductor light emitting devices; and

an assembly device for assembling the plurality of semiconductor light emitting devices from which the foreign substances have been removed on a display substrate,

wherein the foreign substance comprises a magnetic foreign substance and a non-magnetic foreign substance,

wherein the foreign substance removal device comprises a first module having a first bath containing a first fluid to accommodate the plurality of semiconductor light emitting devices and a first separation unit that separates the non-magnetic foreign substance among the foreign substance of the plurality of semiconductor light emitting devices accommodated in the first bath from the magnetic foreign substance and the plurality of semiconductor light emitting devices, and

wherein the first separation unit is configured to rotate the plurality of semiconductor light emitting devices comprised in the first fluid to separate the foreign substance from the plurality of semiconductor light emitting devices, and is configured to move the magnetic foreign substance and the plurality of semiconductor light emitting devices among the separated foreign substance to separate the magnetic foreign substance and the plurality of semiconductor light emitting devices from the non-magnetic foreign substance among the separated foreign substance.