We apply the numerical aperture increasing lens technique to widefield subsurface imaging of silicon integrated circuits. We demonstrate lateral and longitudinal resolutions well beyond the limits of conventional backside imaging. With a simple infrared widefield microscope (λ0 = 1.2μm), we demonstrate a lateral spatial resolution of 0.26μm (0.22λ0) and a longitudinal resolution of 1.24μm (1.03λ0) for backside imaging through the silicon substrate of an integrated circuit. We present a spatial resolution comparison between widefield and confocal microscopy, which are essential in integrated circuit analysis for emission and excitation microscopy, respectively.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics