A handler for sorting semiconductor chips after they have been tested includes a loading unit for loading chips to be tested and an unloading unit for unloading chips that have been already tested. Chips arrive in trays at the loading unit, and a loading picker removes the chips from the tray. When a tray is empty, it is moved over to the unloading unit by a tray transfer mechanism so that tested chips can be placed back into the tray. The tray transfer mechanism rotates the empty trays upside down as it is moved from the loading unit to the unloading unit to ensure that the tray is completely empty before it arrives at the unloading unit.