| 摘要 |
To properly focus an ultraviolet objective lens by the use of a distance sensor even when inspecting an object having a larger step than the focal depth of the objective lens, a difference between the real shape of a convex or concave pattern in each of dies formed on a semiconductor wafer 100 to be inspected and the shape (false shape) of a convex or concave pattern the distance sensor 8 recognizes, is calculated as a correction value C2 intended for use to compensate for an influence of the step in the die. The output from the distance sensor 8 is compensated with the correction value C2 to determine an accurate target moving distance, and an inspection stage 2 is driven accordingly to the target moving distance to automatically focus the ultraviolet objective lens.
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