CD-SEM Metrology for sub-10 nm Width Features

This paper will explore the possibilities of critical dimension scanning electron microscope (CD-SEM) metrology at sub10 nm feature sizes using modeling. JMONSEL simulations will be used to illustrate SEM waveforms for very small features, as a function of beam energy, feature size, profile height and sidewall angle. It will also be shown that the dimensions of the electron beam and interaction volume have very strong influence on the results. Using modeled results, an assessment on required image quality for future tools will be presented, along with a framework for linking spot size and image resolution. Additionally, from the generated waveforms, various measurement algorithms will be evaluated for such future nanometer-scale applications.