Phase defect detection algorithm for extreme ultraviolet mask blank based on watershed edge detection

Extreme ultraviolet (EUV) mask blank lithography technology is recognized as the most promising lithography technology. Small EUV mask defects can also cause large changes in the critical dimensions on the wafer. Therefore, EUV mask manufacturing requirements are very strict. “Zero defect” mask production is still one of the three major challenges of EUV lithography technology. Phase defects, which account for more than half of the mask balnk defects, are difficult to repair and often need to be compensated based on the relevant information of the defect. Therefore, the detection of phase defects is a very important item. In this paper, rigorous simulation and aerial imaging simulation are carried out for the phase defects of extreme ultraviolet mask blanks to obtain typical images of different types of phase defects, and a defect image detection method based on the watershed algorithm is proposed, this method is effective in the detection of extreme ultraviolet mask blank defects.