PURPOSE: An inspection apparatus for wafers is provided to preventing a plurality of wafers from being transferred a post process thorough one time by detecting the overlap of wafers through a vision camera. CONSTITUTION: A picker(30) is installed inside and outside a tank containing liquid and is movable. The picker picks up wafer from wafer mounted in the tank and transfers it. A vision camera(40) is installed outside the tank and takes a picture of picked up wafer. A lighting unit(50) is installed in opposite side of the vision camera and radiates light on the wafer. The light from the lighting unit passes through the picked up wafer is received by the vision camera.
