International comparison of surface roughness and step height (depth) standards, SIML-S2 (SIM 4.8)

• Published in: Metrologia 2006-01, Vol.43 (1A), p.04002-4002
• Main Authors: Doytchinov, K, Kornblit, F, Castellanos, C Colin, Oliveira, J C V, Renegar, T B, Vorburger, T V
• Format: Article
• Language: English
• ISSN: 0026-1394; 1681-7575
• DOI: 10.1088/0026-1394/43/1A/04002

Calibration services of five countries from the Sistema Interamericano de Metrologia (SIM) region are compared through measurements of surface roughness and step height standards. A surface roughness standard with a nominal roughness average (Ra) value of 0.2 mm, a surface roughness standard with a nominal Ra value of 3 mm and a nominal spatial wavelength of 99 mm, and three step height standards with nominal values of 2.55 mm, 0.38 mm and 0.03 mm are compared. Special attention is paid to the influence of the long wavelength cut-off ratio of the measurements. Results are reported for Ra, maximum height of profile Rz, mean width of profile elements RSm, and step height d, depending on the sample measured. The initial reported results show that the laboratories agree on all of the measurements within their stated and published uncertainties. Observations are then discussed about the definition of Rz, the effect of instrument noise on Rz, the different step height parameters d and Pt, differences between the laboratories in reporting Type A statistical uncertainties, the method for calculating the uncertainty of the reference value, and the importance of accounting for correlations between the reference value and individual lab values when calculating the degrees of equivalence. After corrections and reanalysis the laboratories still agree well considering their stated uncertainties.