Nanometer metrology by means of backscattered electrons

A metrological study with a Leica Cambridge (microfabrication) MF 10 cs/120 electron‐beam (e‐beam) machine on metal structures in the nanometer region is presented. The nanometer region (below 100 nm) considered in this study is very challenging when an e‐beam machine is used in the metrological mode, because the feature sizes, in this work ranging between 60 and 170 nm, become comparable to the probe spot size. Thus, a more detailed analysis is necessary in order to extract metrological information properly. Electrons detected by an annular channel plate form the signal from which the metrological data are extracted. Based on this feature, two algorithms, one computational and the other graphical, are proposed and compared. A good agreement between e‐beam‐based and independent scanning electron microscope measurements is found. A statistical study shows an accurate reproducibility below 10 nm with high speed performances. Finally, dimensional control requirements are fulfilled, making the e‐beam machine ...