The numerical aperture increasing lens (NAIL) technique was applied to subsurface thermal emission microscopy of Si integrated circuits (IC). The improvements in the amount of light collected and the spatial resolution, well beyond the limits of conventional thermal emission microscopy were achieved. It was shown that in the experiments, the signal levels are similar, with and without the NAIL, because the NAIL collects more light from the sample, but from a smaller volume. A lateral spatial resolution of 1.4 μm and a longitudinal spatial resolution of 7.4 μm were experimentally demonstrated for thermal imaging at free space wavelengths up to 5 μm.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)