Smoothing sidewalls of a MEMS-based silicon X-ray optics

X-ray optics based on MEMS technologies can provide future astronomical missions with ultra light-weight and high performance optical systems. A silicon optics was fabricated using dry etching and annealing technologies. An angular resolution evaluated in the X-ray wavelength range was about 20 arcmin in full width half maximum, corresponding to 3.1 mm. In this paper, to achieve a better angular resolution, the silicon dry etching and annealing processes are conditioned. The surface roughness of sidewalls were measured at a 100 μm scale. After the conditionings, it has been improved by a factor of four.