Integrated Diffractive Lenses for Ultrathin Silicon

High numerical aperture (NA) laser scanning for fault localization requires the use of special lenses aimed at creating a tightly focused laser spot within an integrated circuit. Typically, extrinsic solid immersion lenses are employed that optimize the refraction at the air-silicon surface. In this feasibility study we investigate with both simulations and experiments the use of integrated diffraction lenses for high-NA imaging. We take the limit to ultrathin silicon and discuss the implications for the lens design and performance.