| Popis: |
A new resist threshold model based on image behaviors on directions parallel as well as normal to feature edges has been developed for predicting critical dimensions (CD) of two-dimension patterns. In this new model (2D-RTM), resist threshold is assumed as a second-order polynomial function of five image parameters that consist of image intensity and slope. Extensive verifications of 2D-RTM have been done by using both rigorous resist models and experimental measurements. 2D-RTM is found to be a good approximation of rigorous model within certain range of dose and defocus variation. For 130nm technology in LSI Logic, 2D-RTM improves CD prediction accuracy for typical 2D patterns to a maximum error of 3.1nm and average of 1.21nm, which gives an improvement of a factor of two compared with conventional resist threshold model. |
