Compact reticle inspection system capable of inspecting a reticle with high accuracy and method of inspecting the same

Abstract

Even though a laser interferometer is affected by the changes in the environment, a reticle can be inspected with a high accuracy by synthesizing a reference image corrected appropriately to compare with an optical image. The reticle which a pattern is plotted in advance is irradiated with a light beam to obtain the optical image from the transmitted light to compare the optical image with the reference image synthesized by converting draft data used at plotting said pattern and to detect defects of the pattern. The reference image is corrected based on the deviation data obtained at the preceding pattern defect detection. The deviation data is the difference between a difference (an initial distance value) between a completion position data and an initiation position data measured before a laser interferometer is affected by the changes in the environment and a difference (a distance data) between the completion position data and the initiation position data measured after being affected by the changes in the environment, and is obtained using a scale is hardly affected by the changes in the environment.