Using a 4-Megapixel Hybrid Photon Counting Detector for Fast, Laboratory-Based Nanoscale X-Ray Tomography

Hybrid photon counting detectors (HPCDs) have unlocked new capabilities for X-ray-based measurements at synchrotrons around the world in the last 30 years. By leveraging independently optimized sensor and readout layers, they offer high quantum efficiency (>80 %), ultra-low dark counts, sub-pixel point-spread function, and high count rates (>106 counts per pixel per second). Furthermore, their small pixel size and large active area endow them with excellent coverage and resolution for both real-space and reciprocal space imaging. Here, we demonstrate that HPCDs are also well-suited for laboratory-based nanoscale X-ray tomography (nano-xCT). We perform nano-xCT on an integrated circuit fabricated at the 130-nm node and produce a 3D reconstruction with over 40 times more photons collected more than 20 times faster than in this group's previous work, for an overall speedup of over 800×. We review the technical considerations of using an HPCD for tabletop tomography. We quantify our reconstruction image quality using well-established metrics, including the modulation transfer function (MTF), Fourier shell correlation (FSC), and contrast-to-noise (CNR), to validate our choice of experimental parameters that provide sufficient resolution and imaging speed. We determine that under current experimental conditions, 160-nm wiring features are reconstructed at 75-80 nm spatial resolution.