Mit Röntgenlithographie gefertigte Gitterstrukturen ermöglichen neue Röntgenbildgebung in Medizin und Materialwissenschaft

All widespread X-ray imaging techniques generate image contrast from the variation in absorption of different materials, which limits the achievable contrast especially for light elements and materials with similar absorption behaviour. A Talbot-Lau interferometer provides the possibility to measure, in addition to the conventional absorption image, the phase shift and a dark field image. These images provide additional information of the sample, establishing entirely new diagnostic possibilities in both medical and materials science. The technique uses periodical grating structures which have to fulfil rigid requirements. On the one hand the period has to be in the range of a few micrometres to enable a compact setup, on the other hand the grating lamellae have to be high enough to absorb the incoming X-rays. This leads to an extreme aspect ratio, which can be reached with X-ray lithography. We present the recent advances in this technique, split into three main work packages: the structures' quality and aspect ratio, the enlargement of the structure area and the reduction of unwanted absorption in the substrate. We further show how these advancements are applied in medical diagnostics and material analysis.