Research on ultra-smooth machining technique for monocrystalline silicon substrate

X-ray mirrors are an important part of the beam line in advanced light sources and have a stringent surface roughness, and monocrystalline silicon is the preferred substrate material for X-ray mirror. A method of improving the surface roughness of X-ray mirror, based on optimized density and dynamic viscosity of the polishing fluid, is analyzed and tested experimentally. The experimental results show that the surface roughness of monocrystalline silicon substrates was reduced significantly, with the root mean square of surface roughness decreasing from 0.420 nm to 0.272 nm, corresponding to an improvement of approximately 32%.