Abstract

Solid-immersion lens (SIL) microscopy requires the dimensions of the SIL to be precisely fabricated, otherwise spherical aberrations will be encountered [1]. Uncorrected spatial aberrations not only degrade the lateral and axial resolutions of a sub-surface microscopy system, but also couple into the time domain to stretch the pulses beyond their minimum transform-limited durations [2]. Chromatic aberration remaps the arrival times at the focal plane of the different colors in the pulse, while spherical aberration changes the position of the best focal plane for each frequency of the pulse. Therefore, time-domain measurements can be applied to diagnose the presence of spatial aberrations, and even to inform an experimental strategy of minimizing their impact. Here we describe an investigation of this approach in the context of sub-surface SIL microscopy of integrated circuits.

© 2017 IEEE