Eschen Wilhelm, Loetgering Lars, Schuster Vittoria, Klas Robert, Kirsche Alexander, Berthold Lutz, Steinert Michael, Pertsch Thomas, Gross Herbert, Krause Michael, Limpert Jens, Rothhardt Jan
Institute of Applied Physics, Abbe Center of Photonics, Friedrich-Schiller-Universität Jena, Albert-Einstein-Str. 15, 07745, Jena, Germany.
Helmholtz-Institute Jena, Fröbelstieg 3, 07743, Jena, Germany.
Light Sci Appl. 2022 Apr 29;11(1):117. doi: 10.1038/s41377-022-00797-6.
Microscopy with extreme ultraviolet (EUV) radiation holds promise for high-resolution imaging with excellent material contrast, due to the short wavelength and numerous element-specific absorption edges available in this spectral range. At the same time, EUV radiation has significantly larger penetration depths than electrons. It thus enables a nano-scale view into complex three-dimensional structures that are important for material science, semiconductor metrology, and next-generation nano-devices. Here, we present high-resolution and material-specific microscopy at 13.5 nm wavelength. We combine a highly stable, high photon-flux, table-top EUV source with an interferometrically stabilized ptychography setup. By utilizing structured EUV illumination, we overcome the limitations of conventional EUV focusing optics and demonstrate high-resolution microscopy at a half-pitch lateral resolution of 16 nm. Moreover, we propose mixed-state orthogonal probe relaxation ptychography, enabling robust phase-contrast imaging over wide fields of view and long acquisition times. In this way, the complex transmission of an integrated circuit is precisely reconstructed, allowing for the classification of the material composition of mesoscopic semiconductor systems.
利用极紫外（EUV）辐射进行显微镜成像有望实现具有出色材料对比度的高分辨率成像，这是因为该光谱范围内波长较短且有众多特定元素的吸收边。与此同时，EUV辐射的穿透深度比电子大得多。因此，它能够对材料科学、半导体计量学和下一代纳米器件中重要的复杂三维结构进行纳米级观察。在此，我们展示了波长为13.5纳米的高分辨率和材料特异性显微镜成像。我们将一个高度稳定、高光子通量的台式EUV光源与一个干涉稳定的叠层成像装置相结合。通过利用结构化EUV照明，我们克服了传统EUV聚焦光学器件的局限性，并展示了横向分辨率为16纳米半间距的高分辨率显微镜成像。此外，我们提出了混合态正交探针弛豫叠层成像法，能够在宽视野和长采集时间内实现稳健的相衬成像。通过这种方式，精确重建了集成电路的复杂透射率，从而可以对介观半导体系统的材料成分进行分类。
