Practical approach to modeling e-beam lithographic process from SEM images for minimization of line edge roughness and critical dimension error

Abstract

Two main factors which limit the minimum feature size and the maximum circuit density achievable by electron-beam (e-beam) lithography are the line edge roughness (LER) and the proximity effect. Since the LER is caused by the stochastic nature of the exposing and development processes, it does not scale with the feature size. Therefore, reducing the LER is essential as the feature size continues to decrease. Accurate modeling of the LER and the proximity effect analytically or via simulation for their minimization is either difficult or costly in many cases. In this study, a practical method for extracting the essential information from SEM images, needed to characterize the e-beam lithographic process, and an effective method for minimizing the LER and critical dimension error based on the extracted information have been developed. The main objective is that the methods utilize only the information extracted from SEM images without having to know the complete setup of e-beam lithographic process. It has been shown that they have a good potential to be further developed into practical and useful tools.