Nanometric lateral scale development with Si/SiO₂ multilayer thin-film structures and improvement of uncertainty evaluation using analysis of variance

A nanometric lateral scale (design pitch: 25 nm) with Si/SiO₂ multilayer thin-film structures was developed. The pitch of the developed nanometric lateral scale was calibrated using an atomic force microscope with a differential laser interferometer, and the uncertainty in pitch measurement was evaluated. In the uncertainty evaluation, two evaluation methods were revised to avoid overestimation. The analysis of variance was applied to the evaluation of uncertainties caused by the nonuniformity of the scale and the repeatability of the measurements in the same location. The expanded uncertainties (k = 2) were 29–154 pm in this study and became smaller than 0.43 nm, which is the expanded uncertainty evaluated in our previous study.