Fabrication of high aspect grating using bonded substrate for X-ray refraction imaging by Talbot-Lau interferometer

Abstract

In order to improve the image quality of X-ray refraction images using a Talbot-Lau interferometer, we have been attempting to fabricate gratings with high aspect ratio. In our attempt, deep grooves of grating structure were channeled on a Si substrate bonded by Au diffusion bonding method, and the grooves were filled with Au where the Au layer used for the bonding Si substrate was acting as a seed layer of Au electroplating. From the results of a visibility measurement and a cross sectional SEM image, it was confirmed that the grooves with a pitch of 5.8 μm and a depth of 100 μm could be successfully filled with Au over a large area of 72×80 mm2. Using this grating, the X-ray refraction images for the cartilage of a knee joint of a livestock pig could be obtained where SPS method was employed for the single-shot image acquisition.