摘要 |
An apparatus for measuring dimensions of a micropattern has a photoelectric sensor for scanning an enlarged image of a pattern and detects the positions of the leading and trailing edges by use of a predetermined slice level from a photoelectric signal which is derived by this sensor, thereby detecting the interval between those edges. The slice level is corrected in accordance with the interval between the edges to be measured. An amount of correction is stored as a predetermined table. A determination is made by an interval discriminating section to see if the correction needs to be performed or not. |