Abstract
The demand for high resolution has raised interest for the use of aplanatic solid immersion lenses (aSIL) for backside optical inspection and failure analysis of integrated circuits due to its high numerical aperture capability. This work investigates the performance of aSIL microscopy in imaging of fully depleted silicon on insulator (SOI) chips and explores the effect of the buried oxide (BOx) thickness on the spatial resolution and photon collection efficiency. Three different cases, namely, bulk silicon, SOI with an ultrathin BOx of 10 nm, and SOI with a standard BOx thickness of 145 nm, are studied. It is observed that there is a 15% drop in the collection efficiency for ultra-thin BOx compared to bulk silicon and up to 80% decrease in the collection efficiency and 30% increase in the spot-size for standard Box.
