| 摘要 |
PURPOSE:To selet focal depth corresponding to a difference in the levels of patterns and to measure a distance between patterns independently of the difference in the levels of the patterns. CONSTITUTION:This fine size measuring instrument is provided with a lighting optical system for irradiating a sample 7 with light, an objective lens 6 for converging reflected light from the surface of the sample 7, a 1st image forming optical system for forming the image of reflected light projected from the lens 6, a high N/A CCD camera 10 for observing a sample image through the 1st image forming optical system, a 2nd image forming optical system for forming an image from a part of the reflected light projected from the lens 6, and a low N/A CCD camera 15 for observing a sample image through the 2nd image forming optical system. An image forming iris 13 for the 2nd image forming optical system is arranged on a position conjugate to the pupil surface of the lens 6. Thus an image with focal depth corresponding to the difference in the levels of patterns can be obtained. |
