The mass absorption coefficient of tungsten and tantalum was measured with soft x-ray photons from 1450 eV to 2350 eV using an undulator source. This includes the M3, M4, and M5 absorption edges. X-ray absorption fine structure was calculated within a real-space multiple scattering formalism; the predicted structure was observed for tungsten and to a lesser degree tantalum as well.Separately, the effects of dynamic screening were observed as shown by an atomic calculation within the relativistic time-dependent local-density approximation.Dynamic screening effects influence the spectra at the 25 % level and are observed for both tungsten and tantalum. We applied these results to characterize spatially-resolved spectra of a tungsten integrated circuit interconnect obtained using a scanning transmission x-ray microscope. The results indicate tungsten fiducial markers were deposited into silica trenches with a depths of 50% and 60% of the markers' heights.
Citation: Journal of Research (NIST JRES) -
Volume: 108 No. 1
NIST Pub Series: Journal of Research (NIST JRES)
Pub Type: NIST Pubs
integrated circuit interconnect, M-sub-3 edge, M-sub-4 edge, M-sub-5 edge, mass absorption, microspectroscopy, tantalum, transmission, tungsten