In recent years, technological progress in nanotechnology has pushed structure sizes to its limits. As an example, in the semiconductor industry, structures well below 100 nm are routinely produced. The characterization of such structures is a demanding and very important task. Classical microscopy methods do not allow direct imaging in this regime because of the Abbe diffraction limit. Nevertheless, characterization of sub-wavelength structures in the far-field is possible using interferometric Fourier transform scatterometry (IFTS) combined with numerical simulation in a feedback loop. Here, we show that the resolution of this method can be considerably enhanced by use of additional plasmonic nanoantennae structures which transform scattering near-field information into the optical far-field. These structures were realized using different photofabrication approaches.
© 2015 C. Reinhardt et al., published by De Gruyter.