| 摘要 |
<p>PROBLEM TO BE SOLVED: To determine the rotation direction of a wafer without requiring a sensor dedicated for detecting notchs on the wafer by increasing the level for evaluating the extent of matching in either one of a plurality of rotational states where the relative rotational angle between an image to be processed and the image of a temple is different. SOLUTION: A wafer to be measured is mounted on a stage and held in place (S201). Image at the central position of the wafer is then read out and stored as an image to be processed in a specified area of an image processing unit (S202). Subsequently, evaluation value of matching is calculated for 36 rotating template images having a rotational angular interval of 10 deg. in the range of 0-350 deg. (S203). Thereafter, a plurality of rotational template images are formed by turning the template image sequentially at a fine angular interval in the vicinity of a rotational angle having a highest matching evaluation value (S204). Finally, the rotational angle of a wafer to be measured is determined using the rotational angle having a highest matching evaluation value (S205).</p> |
