Fabrication of High Aspect Ratio X-ray Grating Using Silicon Dry Etching Method

We have fabricated the high aspect ratio X-ray gratings for X-ray phase imaging. Silicon dry etching technology makes it possible to fabricate rectangular structures by repeating two steps of etching process and protection process. Then, we introduce the ability of Si dry etching technology in order to fabricate un-tapered, high precision Si microstructures containing rectangular patterns for X-ray grating. Au electroforming was realized from the bottom of the Si microstructure groove using sidewall protection method. In these technologies, we succeeded in fabricating about 40 mu m thick, void-free Au structures in a space as narrow as 2.6 mu m in large effective area of 60 mm squares on 4 inch Si wafer. Therefore, it is expected to be used in the production of a narrow pitch and higher aspect ratio microstructures such as X-ray gratings.