Correction system, correction method and wafer box

A correction system, a correction method and a wafer box for correcting wafer contraposition of a wafer transfer system having wafer transfer blades are provided. The correction method includes providing a wafer cassette having a plurality wafer slots in a horizontal direction, wherein each wafer slot is provided with a plurality of opposed grooves, each of the opposed groove includes a top surface, side surfaces and a bottom surface; placing conductive material on the top surfaces of the opposed grooves of the first wafer slot to electrically communicate with a detector so as to detect when the wafer is contacted with the conductive material; transferring the wafers placed on the wafer transfer blades to the first wafer slot; and judging whether or not the wafers in the first wafer slot are aligned. The system and method of the invention may be used for correction in X, Y and Z directions.