| 摘要 |
PROBLEM TO BE SOLVED: To provide a photomask inspection method for detecting foreign substances, such as, dust on a photomask with high sensitivity.SOLUTION: The inspection method for a photomask, having a first region and a second region, having a higher reflectance to inspection light than in the first region, on the surface comprises: acquiring a reflection image of the photomask; creating an undershoot image of the reflection image through a process of rewriting the pixel value of a pixel, having a pixel value equal to or higher than the reflection intensity in the first region into a pixel value in the first region; creating an SSD (sum of squared differences) image including the sum of the squared difference between the undershoot image and a raised concave kernel; creating a local dark portion enhanced image through a smoothing process on the SSD image; and detecting a foreign substance by comparing the local dark portion enhanced image with a predetermined threshold. |
