PURPOSE: To reduce a space required for a cleaning operation, to save a chemical liquid and pure water and to enhance a cleaning effect by a method wherein only a semiconductor wafer is taken out from a wafer carrier and the cleaning operation is executed.

CONSTITUTION: In an automatic transfer system, a wafer 21 is transferred by using a fork-shaped arm 23 of a lifter and is lowered to a lower-part loading part. During a lowering operation, an arm 24 of an orientation-flat lining-up device of wafers is shifted to a lower-part of the wafer carrier 21 ; a rotary roller 25 installed at the arm 24 is brought into contact with the wafers 20; the rotary roller 25 is turned; the wafers are lined up in such a way that a position of an orientation flat of the wafers faces in a lower-part direction. The fork-shaped arm 23 is lowered; only the wafers 20 are shifted to grooves of a wafer-mounting stage 26 installed at a loading part 27 and are positioned. The wafer carrier 21 is lowered to a loading position while it is mounted on the arm 23. The wafers 20 lined up on the water-mounting stage 26 are held by the transfer arm and are raised; after that, an immersion operation is executed according to a process sequence.