Abstract
Silicon micropore optics using deep reactive ion etching of silicon wafers has been being developed for future x-ray astronomy missions. Sidewalls of the micropores through a thin wafer with a typical thickness of hundreds of micrometers and a pore width of are used for x-ray mirrors. However, burr structures observed after etching with a typical height of a few micrometers at the micropore edges are known to significantly reduce x-ray reflectivity. A new grinding and chemical mechanical polishing process is introduced to remove the burr structures. Both sides of the silicon wafer were ground and precisely polished after etching. X-ray reflectivity measurements confirmed an increase of reflectivity by 2–15 times at incident angles of 0.8–0.2 deg. The surface microroughness worsened from to ; however, an additional annealing recovered the smooth surface and the estimated surface microroughness was . This new process enables not only removing the burr structures but also choosing a flat part of the sidewalls for better angular resolution.
© 2019 Optical Society of America
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