Development of a standard scale calibrator for low uncertainty of measurement

6th report: Evaluation of optics-induced error

Abstract

Measurement error due to the defocus and the curved caustic of the optical system of the line-detecting microscope for the line scale calibration system was investigated. A procedure for evaluating this type of error was proposed. Comparative measurements were carried out using the proposed procedure for two conditions of an objective lens of NA=0.175 with better adjustment and a lens of NA=0.4 with standard adjustment. The results were 4 nm for NA=0.175 and approximately 200 nm for NA=0.4 at a defocus range of ±10 um.