Demonstration of ultra high resolution soft x-ray tomography

Ultra high resolution three dimensional images of a microscopic test object were made with soft x‐rays using a scanning transmission x‐ray microscope. The test object consisted of two different patterns of gold bars on silicon nitride windows which were separated by ∼ 5μm. Depth resolution comparable to the transverse resolution was achieved by recording nine 2‐D images of the object at angles between −50 to +55 degrees with respect to the beam axis. The projections were then combined tomographically to form a 3‐D image using an algebraic reconstruction technique (ART) algorithm. We observed a transverse resolution of ∼1000 A. Artifacts in the reconstruction limited the overall depth resolution to ∼6000 A, however some features were clearly reconstructed with a depth resolution of ∼1000 A.