Soft x-ray scanning microtomography with submicrometer resolution

Scanning soft x‐ray microtomography was used to obtain high‐resolution three‐dimensional images of a microfabricated test object. Using a special rotation stage mounted on the scanning transmission x‐ray microscope at the X1A beamline at the National Synchrotron Light Source, we recorded nine two‐dimensional projections of the 3D test object over an angular range of −50° to +55°. The x‐ray wavelength was 3.6 nm and the radiation dose to the object per projection was approximately 2×106 Gy. The object consisted of two gold patterns supported on transparent silicon nitride membranes, separated by 4.75 μm, with 100‐ to 300‐nm‐wide and 65‐nm‐thick features. We reconstructed a volumetric data set of the test object from the two‐dimensional projections using an algebraic reconstruction technique algorithm. Features of the test object were resolved to ∼100 nm in transverse and longitudinal extent with low artifact in three‐dimensional images rendered from the volumetric set.