A developed technology for chemical-mechanical polishing of large-sized single-crystal silicon substrates for X-ray optical applications is reported. Compared to the standard technology of chemical-mechanical polishing of silicon wafers for microelectronics, which emphasizes the atomic smoothness of substrates and a small damaged layer, high accuracy of the surface shape is demanded, which can be either flat or curved. Materials for polishing pads and suspensions for mechanical lapping and chemical-mechanical polishing, as well as the main parameters of the processing, were found that ensured an effective surface roughness of 0.17 nm in the spatial frequency range 0.025–65 μm and a root-mean-square error of 8.86 nm of the surface shape deviating from the plane. The surface obtained using the developed technology is not inferior in roughness to the results of the world’s leading manufacturers of silicon wafers for microelectronics and significantly surpasses it in shape accuracy.
Chkhalo et al. (2025) studied this question.