| 摘要 |
PROBLEM TO BE SOLVED: To measure the flatness of a wafer at high speed and with high precision, even when there is variation in its size, by measuring a deviation in its rotation center and correcting the deviation at high speed and with high precision. SOLUTION: While a board 14 is held and rotated, the rotation speed and the outside shape thereof are measured. On the basis of the shape of the board 14, a positional deviation from the center of the board 14 itself to its rotation center is calculated. When the board 14 is rotated, using a deviation sensor which scans in the direction of the surface of the board 14, distance from the deviation sensor to the surface of the board 14 or a change in the distance is measured for a plurality of measurement points with respect to a coordinate system having the rotation center of the board 14 as its origin. By the calculated positional deviation, the positional data of the measurement points by the deviation sensor are corrected to a coordinate system having the center of the board 14 itself as its origin. On the basis of the corrected positional data, thickness irregularities and curves on the surface of the board 14 are calculated. COPYRIGHT: (C)2006,JPO&NCIPI
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