High spatial resolution subsurface thermal emission microscopy

Abstract

We apply the numerical aperture increasing lens technique to subsurface thermal emission microscopy of Si integrated circuits. We achieve improvements in the amount of light collected and the spatial resolution, well beyond the limits of conventional thermal emission microscopy. We experimentally demonstrate a lateral spatial resolution of 1.4 μm and a longitudinal spatial resolution of 7.4 μm, for thermal imaging at free space wavelengths up to 5 μm.