| 摘要 |
PURPOSE: To solve such a problem that focus detection accuracy is deteriorated by the influence of a pattern formed on an object to be inspected, and the focus detection accuracy is deteriorated by dust on the object, and also, by the presence of a level difference on the object after finishing. CONSTITUTION: After detecting a focus, the object to be inspected in scanned following the focus detection, the focus detecting operation is performed many times and averaged, and an objective lens is driven based on the average value, and by repeatedly averaging, the focus detecting position is converged. |
