| 摘要 |
PURPOSE:To form at a low cost a microscopic dimension measuring device using an optical secondary differential method, by oscillating microscopically an optical spot of a laser beam, and also detecting the intensity of a reflected light in three points of the optical spot, like time division. CONSTITUTION:Laser light 11 is condensed like a spot by lenses 13, 15 and this optical spot 2 scans on a pattern to be measured, by which width of a pattern 5 is measured. In this case, a high speed and microscopic oscillation is given to the spot light 2 by an ultrasonic optical polarizer 12, and also intensity of a reflected light in three points of the optical spot 2 is detected like time division. In accordance with a reflected light intensity signal obtained in this way, the secondary differentiation is executed and an edge position pulse signal 8 is formed. By this signal 8, width of the pattern 5 is derived. In this way, a microscopic dimension measuring device using an optical secondary differentiation method can be formed at a low cost. |
