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The development of next-generation semiconductor technologies necessitates the use of modern methods for monitoring electronic circuit topology parameters, including critical dimensions, material homogeneity, and roughness. These challenges are particularly pressing in the fabrication of templates for high-aperture projection lithography in the extreme UV (EUV) and beyond (EUVL, BEUVL) ranges and the rapid inspection of the surfaces and layers of millions of memory chips written using image reduction and shifting [1].
Compared to SEM and AFM, a non-imaging indirect Short-Wave Scatterometry (SWS) method can simultaneously have a high spatial resolution (0.1–10 nm) and large fields of view (0.1–10 mm), which allows for rapid and reliable tracking of critical parameters of microcircuit topology and analysis of their homogeneity. Analysis of X-ray scattering intensity under normal and grazing incidence conditions using synchrotron or laboratory sources, including plasma-laser sources of coherent or partially coherent radiation, and solving the inverse scattering problem allows for the determination of the morphology of the analyzed structures and the composition of their materials with high accuracy and sub-second time resolution. SWS is a method of integral metrology that provides averaging of the electron density, critical dimensions, and roughness over a large observation spot in a specific projection. One of the most widely used metrology methods today, grazing small-angle X-ray scattering (GISAXS), is also related to SWS [2]. For the analysis of nanoscale objects with 3D topology, additional reference methods can be used, for example, X-ray or EUV ptychography [3].
The generally accepted approach to characterizing chips with various 3D element topologies uses single- and bi-periodic diffraction gratings with trapezoidal groove profiles, including multilayer ones, recorded in the process, with corresponding linear and angular dimensions and roughnesses. For the analysis of single-periodic gratings, primarily probe radiation incidence patterns along the grooves (conical diffraction) are used, while for bi-periodic gratings, a general 3D diffraction pattern described by two incidence angles and two polarization angles is used [4]. Using the exact or approximate solution of complex inverse problems on gratings, SWS is used to evaluate the quality (suitability) of a mask or chip (fragment) for further processing, as well as the potential for reducing Raman scattering and improving lithography quality.
1. https://www.asml.com/en/products/euv-lithography-systems
2. Wen-li Wu, R. Joseph Kline, Ronald L. Jones, et al., JM3 22(3), 031206 (2023). https://doi.org/10.1117/1.JMM.22.3.031206
3. I.A. Artyukov, N.L. Popov, A.V. Vinogradov, Symmetry 13(8), 1439 (2021), https://doi.org/10.3390/sym13081439
4. K.V. Nikolaev, L.I. Goray, P.S. Savchenkov, et al., publ. in JACr (2026). arXiv:2507.23513