APPARATUS FOR MEASURING LENGTH OF ELECTRON BEAM

摘要

PURPOSE:To detect whether or not the measured result is correct the automatically-measured length is outside an expected allowance in an apparatus for measuring electron beams. CONSTITUTION:An image display means 70 displays magnified images of a to-be-measured object. An automatic length measuring means 20 automatically measures the dimension of the displayed magnified image at an expected position. An allowance setting means 30 sets an allowance related to the dimension of the expected position. A comparing/detecting means 40, comparing the measured result with the allowance, detects whether the measured result is within the allowance. A deciding data memory means 50 stores the data to decide whether the detection is correct when the measured result is detected to be outside the allowance. A re-display means 60 displays an image of the deciding data stored in the memory means 50.