19 May 2008 Reliable measurement method for complicated OPC pattern
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Proceedings Volume 7028, Photomask and Next-Generation Lithography Mask Technology XV; 70281N (2008) https://doi.org/10.1117/12.793064
Event: Photomask and NGL Mask Technology XV, 2008, Yokohama, Japan
Abstract
The application of aggressive Optical Proximity Correction (OPC) has permitted the extension of advanced lithographic technologies. OPC is also the source of challenges for the mask-maker. Small shapes between features and highly-fragmented edges in the design data are difficult to reproduce on masks and even more difficult to measure exactly with CD-SEM, which requires not only tool stability but also better measurement methods. To cope with this problem, we have been focusing on finding better methods for measuring actual mask Critical Dimension (CD) that would show a good correlation to wafer CD. In BACUS 2006, we presented an effective measurement for closed patterns, which is "area measurement". In time paper we are introducing new potential solution, which include a reliable method, distance measurement, for certain types of unclosed patterns. For instance, we evaluated an unclosed pattern which couldn't be measured with Region of Interest (ROI) that is large enough, and found a reliable method, Distance ROI. Though the method has a major drawback of image tilt, we also found an approach to avoid this. Finally we verified that Distance ROI could be new solution for unclosed patterns by jointly applying tilt monitoring, beam rotation correction, and area scan.
© (2008) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Tastuya Aihara, Shinpei Kondo, Masaru Higuchi, "Reliable measurement method for complicated OPC pattern", Proc. SPIE 7028, Photomask and Next-Generation Lithography Mask Technology XV, 70281N (19 May 2008); doi: 10.1117/12.793064; https://doi.org/10.1117/12.793064
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