ULTRAHIGH-RESOLUTION X-RAY TOMOGRAPHY

Ultrahigh-resolution three-dimensional images of a microscopic test ob ject were made with soft x-rays collected with a scanning transmission x-ray microscope. The test object consisted of two different patterns of gold bars on silicon nitride windows that were separated by simila r to 5 micrometers. Depth resolution comparable to the transverse reso lution was achieved by recording nine two-dimensional images of the ob ject at angles between -50 and +55 degrees with respect to the beam ax is. The projections were then combined tomographically to form a three -dimensional image by means of an algorithm using an algebraic reconst ruction technique. A transverse resolution of similar to 1000 angstrom s was observed. Artifacts in the reconstruction limited the overall de pth resolution to similar to 6000 angstroms; however, some features we re clearly reconstructed with a depth resolution of similar to 1000 an gstroms.