Assessment of High Accuracy 3D Shape Analysis

When absorption or scattering is large, the accuracy of shape measurement is about 100 wavelengths, but it can be improved to about a wavelength by using scatterometry. Since scatterometry uses a calculation method that can strictly consider diffraction and polarization, the calculation time and the amount of memory are significantly larger than those of an approximation method that does not consider them. Therefore, we have developed a high-speed simulation method with a small memory size using rigorous coupled wave analysis which is popular for scatterometry. In this report, using this method, the width of each cross section of a two-layer column was measured by soft X-ray scatterometry. The scintillation radiation of wavelength 10 nm was applied to the isolated scatterer in the vacuum system. In this research, we have shown that the resolution is at least a few wavelengths.