Extension of the range of profile surface roughness measurements using metrological atomic force microscope

Abstract

The calibration service of profile surface roughness by using a metrological atomic force microscope is now available at National Metrology Institute of Japan (NMIJ), AIST. The calibration method is designed by referring to ISO 19606: 2017 (JIS R 1683: 2014). The scope of the ISO 19606: 2017, however, is limited to roughness measurements of surfaces with an arithmetical mean roughness, Ra, in the range of about 1 nm–30 nm. Currently there is strong demand for the measurement of surface roughness of more than 30 nm in the precision machining industry and for the measurement of surface roughness of sub-nanometer order in the semiconductor industry. In order to meet such demand, it is necessary to extend the range of surface roughness measurements in the NMIJ's calibration service. In this study, authors performed surface roughness measurements using a metrological AFM and evaluated their uncertainties. As a result of a series of measurements and evaluation of their uncertainties, it has been found that the calibration range can be extended to surfaces with an arithmetical mean roughness, Ra, in the range of about 0.2 nm–100 nm. The measurement results and the future challenges are reported in this paper.