A wafer boat assembly for use with a loading apparatus configured to insert the wafer boat assembly loaded with semiconductor substrates into a furnace. The wafer boat assembly includes a first wafer boat part comprising a base and a first cover part mounted on the base; and a second wafer boat part comprising a second cover part that is provided with receiving slots for holding a plurality of semiconductor substrates. The second cover part has an arcuate shape that extends from a first longitudinal edge to a second longitudinal edge. The first and second wafer boat parts are detachably connectable, such that they mate together to extend around an outer perimeter of a loaded substrate at a predetermined distance.