| 摘要 |
PURPOSE: To detect only those defects around the edge of a circuit pattern which affect the true functions of a circuit by evaluating the importance of the defects in more detail. CONSTITUTION: A deviation detecting portion 10 and a position correcting portion 12 correct the deviation of an image to be inspected from a reference image. Using a signal of the image to be inspected and a reference image signal after the correction of the deviation, a difference image generating portion 14 generates a difference signal SD from which a small difference pattern that can be neglected as a defect is eliminated, and a difference judging signal SJ showing whether or not the difference pattern is in a remaining copper system, and an edge extracting portion 16 generates an edge signal SE showing the edge of a circuit pattern. Using the signals SD, SJ, SE, a length measuring portion 18 calculates the distance DIS from the edge to the difference pattern, the size SIZ of the difference pattern, and the width W of the circuit pattern. A defect judging portion 20 then determines whether or not a defect exists according to the ratio SIZW when the difference pattern touches the edge, and according to the product of DIS and W when the difference pattern does not touch the edge. |
