Three-Dimensional SEM Metrology for Nanoelectronics

摘要

Our world is three-dimensional, and so are the integrated circuits (ICs) and the devices of nanoelectronics. In the past, for a long time, we have been very fortunate, because it was enough to measure a simple critical dimension (CD), the width of the resist line, to keep IC production under acceptable control. In the last few years with complex chip architectures this requirement has changed to contour and now to three-dimensional (3D) measurements. At some point in the future it will be necessary to know where individual atoms are and what are the electrical properties of only a few of them.While this today seems bordering impossibility, the latest results obtained by NIST researchers using sophisticated modeling combined with high-quality scanning electron microscope (SEM) imaging show promise, at least a significant step forward. 3D simulation and model-based assessments of the possibilities indicate that measurements of at least 5 nm size structures will not pose an insurmountable obstacle. Results of SEM measurements and Monte Carlo modeling and simulation presented here identify the ways instrument and measurement method development should move to be able to provide indispensable 3D dimensional and compositional information on various current and future devices of nanoelectronics.