Nanoscale Three-Dimensional Imaging of Integrated Circuits Using a Scanning Electron Microscope and Transition-Edge Sensor Spectrometer

• Published in: Sensors (Basel, Switzerland) Vol. 24; no. 9; p. 2890
• Main Authors: Nakamura, Nathan, Szypryt, Paul, Dagel, Amber L, Alpert, Bradley K, Bennett, Douglas A, Doriese, William Bertrand, Durkin, Malcolm, Fowler, Joseph W, Fox, Dylan T, Gard, Johnathon D, Goodner, Ryan N, Harris, James Zachariah, Hilton, Gene C, Jimenez, Edward S, Kernen, Burke L, Larson, Kurt W, Levine, Zachary H, McArthur, Daniel, Morgan, Kelsey M, O'Neil, Galen C, Ortiz, Nathan J, Pappas, Christine G, Reintsema, Carl D, Schmidt, Daniel R, Schultz, Peter A, Thompson, Kyle R, Ullom, Joel N, Vale, Leila, Vaughan, Courtenay T, Walker, Christopher, Weber, Joel C, Wheeler, Jason W, Swetz, Daniel S
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 30.04.2024
• Subjects: Chemistry; computed tomography; Electron microscopes; Energy; Engineering; Failure analysis; Geometry; Instruments & Instrumentation; Integrated circuit fabrication; Integrated circuits; Laboratories; Semiconductor chips; Sensors; Three dimensional imaging; Tomography; X-ray imaging; X-ray nanotomography; X-rays; X-ray nanotomography; computed tomography; integrated circuits; X-ray imaging
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s24092890

X-ray nanotomography is a powerful tool for the characterization of nanoscale materials and structures, but it is difficult to implement due to the competing requirements of X-ray flux and spot size. Due to this constraint, state-of-the-art nanotomography is predominantly performed at large synchrotron facilities. We present a laboratory-scale nanotomography instrument that achieves nanoscale spatial resolution while addressing the limitations of conventional tomography tools. The instrument combines the electron beam of a scanning electron microscope (SEM) with the precise, broadband X-ray detection of a superconducting transition-edge sensor (TES) microcalorimeter. The electron beam generates a highly focused X-ray spot on a metal target held micrometers away from the sample of interest, while the TES spectrometer isolates target photons with a high signal-to-noise ratio. This combination of a focused X-ray spot, energy-resolved X-ray detection, and unique system geometry enables nanoscale, element-specific X-ray imaging in a compact footprint. The proof of concept for this approach to X-ray nanotomography is demonstrated by imaging 160 nm features in three dimensions in six layers of a Cu-SiO integrated circuit, and a path toward finer resolution and enhanced imaging capabilities is discussed.