| 摘要 |
PURPOSE:To provide a pattern tester in which an accurate focal position can be obtained at all times by correcting the drift of a focus system. CONSTITUTION:A pattern tester is designed so as to observe a plurality of patterns, which are drawn on a sample in the same design pattern, by different detecting means respectively and to compare and test the difference between the both patterns by a testing means, or to observe patterns drawn on the sample by a detecting means and compare and test the obtained pattern and design data by a testing means. Then, a reference pattern 12 for detecting focal position is prepared on a table 1 where a sample 2 is loaded and can be moved in a specified direction, and the pattern 12 is irradiated with a light from a light source 3. Further, the obtained transmissive light or reflecting light is received by a sensor 5 through an optical system 4, and the focal position of the system 4 is measured based on the output of the light reception result, thereby correcting the focal position. |
