MARK DETECTING METHOD IN CIRCULAR BODY, NOTCH DETECTING METHOD, DIRECTION INSPECTION METHOD FOR SEMICONDUCTOR WAFER AND DIRECTION INSPECTION DEVICE FOR SEMICONDUCTOR WAFER

PROBLEM TO BE SOLVED: To accurately detect a fine mark formed on the peripheral section of a circular body. SOLUTION: Edge extraction processing is carried out to an image obtained by image-picking up a wafer, and the center point O1 of the wafer is extracted on an obtained edge image. An annular window W including the peripheral section of the wafer is set on the basis of coordinates of the center point 01 and the radius D of the wafer. Points constituting the circular arc of a circle around the center point O1 are extracted in the window, these points are erased, and a pair of edge sets positioned at an interval corresponding to the width of a notch are extracted in the window W. A representative point in a pair of the edge set is obtained, and whether or not the wafer is directed in the correct direction can be decided by obtaining an angle indicating the direction viewing the representative point from the center point O1. COPYRIGHT: (C)2005,JPO&NCIPI