31 October 2007 More robust model built using SEM calibration
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More robust Optical Proximity Correction (OPC) model is highly required with integrated circuits' CD (Critical Dimension) being smaller. Generally a lot of wafer data of line-end features need to be collected for modeling. Scanning Electron Microscope (SEM) images are sources that include vast 2D information. Adding SEM images calibration into current model flow will be preferred. This paper presents a method using Mentor Graphics' Calibre SEMcal and ContourCal to integrated SEM calibration into model flow. Firstly simulated contour is generated and aligned with SEM image automatically. Secondly contour is edited by fixing the gap etc. CD measurement spots are applied also to get a more accurate contour. Lastly the final contour is extracted and inputted to the model flow. EPE will be calculated from SEM image contour. Thus a more stable and robust OPC model is generated. SEM calibration can accommodate structures such as asymmetrical CDs, line end pullbacks and corner rounding etc and save a lot of time on measuring line end wafer CD.
© (2007) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Ching-Heng Wang, Qingwei Liu, Liguo Zhang, "More robust model built using SEM calibration", Proc. SPIE 6730, Photomask Technology 2007, 673053 (31 October 2007); doi: 10.1117/12.740411; https://doi.org/10.1117/12.740411

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