Exploring the limits of scanning electron microscopy for the metrology of critical dimensions of photoresist structures in the nanometer range

Statistical fluctuations of the critical dimensions in the Front-End-of-Line represent a challenge for the yield and reliability of CMOS technologies in the sub-22 nm nodes. This implies the use of advanced characterization techniques with resolution capabilities in the sub-nanometer range. In this paper, the ability of scanning electron microscopy to achieve the required level of uncertainty is investigated by Monte Carlo simulation. Examples based on the model library approach are shown, which deal with the extraction of the critical dimensions in photoresist lines and contact holes with line edge roughness.