Submicrometre-pitch intercomparison between optical diffraction, scanning electron microscope and atomic force microscope

Intercomparison of pitch measurements for one-dimensional-grating standards (240 nm pitch), one of the widely used reference standards for nanometric lateral scales, was performed by three different methods, optical diffraction, critical dimension scanning electron microscopy and nanometrological atomic force microscopy. Average pitch values obtained by the three methods deviated by a maximum of only 0.67 nm with expanded uncertainties (k = 2) of less than 1.2 nm. The calculated En number, the index of measurement quality, of less than 1 indicates consistency of the measured pitch values and subsequent uncertainty analyses performed by three methods.