A standard used for probe-tip diameter evaluation in surface roughness measurements using metrological atomic force microscope

Recently metrological atomic force microscopes (metrological AFMs) have been used for surface roughness measurements. The National Metrology Institute of Japan (NMIJ), AIST, provides a profile surface roughness calibration service using a metrological AFM based on ISO 19606:2017. This international standard requires evaluation of probe-tip diameter D and error in roughness measurements by using a standard plate with needle-shaped spikes before conducting surface roughness measurements. However, the conventional standard plate has several problems: (1) the needle-shaped spikes are too high, (2) the distance between spikes is too long, and (3) the spike curvature radius is not small enough, compared with AFM probe-tip size, which may lead to considerable uncertainty derived from probe-tip error evaluation. This study examined a new type of commercially-available standard plate as a candidate for probe-tip diameter evaluation. It features lower spike height and shorter distance between spikes in order to avoid probe-tip wear caused by repeated scanning. This study demonstrated that the overestimated uncertainty derived from probe-tip error evaluation can be corrected by using the new standard plate.