Bringing SEM-contour based OPC to production

Calibrating an accurate OPC model usually requires a lot of one-dimensional CD-SEM measurements. A promising alternative is to use a SEM image contour approach but many challenges remain to implement this technique for production. In this work a specific flow is presented to get good and reliable contours well matched with traditional CDSEM measurements. Furthermore this work investigates the importance of site selection (number, type, image space coverage) for a successful contour-based OPC model. Finally the comparison of conventional and contour based models takes into account the calibration and verification performances of both models with a possible cross verification between model data sets. Specific advantages of contour based model are also discussed.