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11 March 1994 Defect inspection of periodic patterns with low-order distortions
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Proceedings Volume 2183, Machine Vision Applications in Industrial Inspection II; (1994) https://doi.org/10.1117/12.171210
Event: IS&T/SPIE 1994 International Symposium on Electronic Imaging: Science and Technology, 1994, San Jose, CA, United States
Abstract
A self-reliance technique is developed for detecting defects in repeated pattern wafers and masks with low-order distortions. If the patterns are located on a perfect rectangular grid, it is possible to estimate the period of repeated patterns in both directions, and then produce a defect-free reference image for making comparison with the actual image. But in some applications, the repeated patterns are somehow shifted from their desired position on a rectangular grid, and the aforementioned algorithm cannot be directly applied. In these situations, to produce a defect-free reference image and locate the defected cells, it is necessary to estimate the amount of misalignment of each cell beforehand. The proposed technique first estimates the misalignment of repeated patterns in each row and column. After estimating the location of all cells in the image, a defect-free reference image is generated by averaging over all the cells and is compared with the input image to localize the possible defects.
© (1994) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Babak H. Khalaj, Hamid K. Aghajan, Arogyaswami Paulraj, and Thomas Kailath "Defect inspection of periodic patterns with low-order distortions", Proc. SPIE 2183, Machine Vision Applications in Industrial Inspection II, (11 March 1994); https://doi.org/10.1117/12.171210
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