METHOD FOR ALIGNING WAFER

摘要

PURPOSE: A method for aligning a wafer is provided to enable a correction even in the case of a big rotation error, by aligning the position of the wafer with respect to a vertex with which the devices formed on the wafer come in contact before the wafer is transferred to an exposure stage. CONSTITUTION: The position of a notch of the wafer is read. The wafer is so transferred that the read notch is located in a predetermined notch position. Arbitrary two vertexes most adjacent to an arbitrary vertical line on the wafer are selected out of the vertexes with which the devices formed on the firstly-aligned wafer come in contact. Horizontal coordinates of the two vertexes are read and the values of the horizontal coordinates are determined to be x1 and x2. The difference between x1 and x2 is calculated. The wafer is rotated to make the difference becomes a zero so that the rotation error of the wafer is corrected. The secondly-aligned wafer is transferred to the exposure stage. An align mark on the wafer transferred to the exposure stage is read. The wafer is transferred to make the read align mark located in a predetermined position so that the center and rotation error of the wafer is corrected.