Measurement of the 100 nm NIST SRM® 1963 by laser surface light scattering

Accurate sizing of particles deposited on surfaces is important for the semiconductor, optical, and data storage industries. The recent availability of accurate light scattering models for non-ideal conditions enables the determination of particle size with a complete assessment of the measurement uncertainties. In this manuscript, we describe a light scattering measurement of the National Institute of Standards and Technology (NIST) Standard Reference Material (SRM®) 1963 deposited onto a silicon wafer. The measurement was carried out using 441.6 nm, p-polarized light. The measurement yielded a value of 99.7 nm with an expanded run uncertainty (95% confidence limit) of 1.7 nm. The uncertainty is dominated by the reproducibility of the measurement. Uncertainties in the substrate optical properties, the thickness and optical properties of the substrate oxide, and the shape of the particle dominate the systematic uncertainty.