12-inch X-ray optics based on MEMS process

Abstract

A large size X-ray optic with a 12-inch silicon wafer is fabricated to increase X-ray collecting power. The 12-inch silicon optic is formed by a combination of photolithography, dry etching and chemical mechanical polishing techniques. Furthermore, in order to smooth surfaces of the etched sidewalls used as X-ray reflection plane, the optic is annealed with high temperature. To verify the surface profile, X-ray reflectivity measurements are conducted with Al K$_{\alpha }$ 1.49 keV and reflected X-rays are detected for the first time. From the X-ray reflectivity data, it is suggested that the optic has ridge and slope structures on the sidewall surfaces, which decrease the reflection region by shadowing a part of the sidewall surface and changing a practical incident angle. An estimated surface roughness is $\sim$2 nm rms, which is consistent with the surface profiles measured by an atomic force microscope.