Image grey value based mask optical defect detecting method

Abstract

The invention discloses an image grey value based mask optical defect detecting method. The method includes steps: acquiring bright area data and dark area data of an actual image on a camera interface; adopting a camera flat field correction function for camera view field brightness correction of the actual image to guarantee value maintenance of grey values of a bright area and a dark area in aview field, and keeping uniform as far as possible; selecting a dark area on a calibration plate of the actual image, and calibrating a grey value to be V1; selecting a bright area on the calibrationplate of the actual image, and calibrating a grey value to be V2; recording the calibrated grey value V1 of the dark area and the calibrated grey value V2 of the bright area into a Recipe template toserve as subsequent mask detection parameters, and directly applying the subsequent mask detection parameters as grey values of standard image generation bitmap to keep uniformity of the grey values of the actual image and the grey values of a standard image as far as possible; after image registration, subjecting the actual image and the standard image to absolute subtraction operation to furtherjudge whether the actual image has defects or not. By adoption of the method, defect detection accuracy can be improved, and great detection effects are achieved.

Description

Technical field [0001] The invention relates to a method for detecting optical defects of a mask plate based on an image gray value, and belongs to the technical field of semiconductor detection. Background technique [0002] At present, after the semiconductor mask is etched, the defects on the graphics are particularly important to the quality of the subsequent process. If optical inspection is used, the collected grayscale image will generally be binarized by the camera, and then combined with the black and white standard image. Contrast inspection, but if the effect is good, the performance is consumed, and the fast binarization is performed, the effect is not good; the effect of binarization directly affects the accuracy of defect detection. Summary of the invention [0003] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a mask optical defect detection method based on the image gray value, by which the defec...

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Problems solved by technology

[0002] At present, after the semiconductor mask is etched, the defects in the graphics are particularly important to the quality of the subsequent process. If optical inspection is used, the grayscale image collected is usually binarized by the camera, and then compared with the black and white standard image. Contrast detection, but if it consumes performance for good effect, the effect of fast binarization is not good; the effect of binarization directly affects the accuracy of defect detection

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