| 摘要 |
PROBLEM TO BE SOLVED: To enhance the resistance to vibration, and perform an automatic focusing on the basis of the previous data by using only the reflected light from a selected small area in the focusing necessary for performing the original inspection measurement in a scanning area. SOLUTION: An optical path 99 is opened through by a shutter 125. A first wafer is placed on a stage 101 by the instruction from a computer. The stage 101 is moved to the X/Y coordinate point of a measuring point, and when the measuring point is conformed to the optical axis, a system performs a focusing. In this processing, a diode group preliminarily selected from a detector array 118 and partially superposed on a background image, or the output from a photo sensor is used. A section (focusing section) particularly performing the focusing is judged to be in the focused state when the coherence measured value therein calculated on the basis of the output of the photodiode is maximum. |
