Colloquium with Prof. Dr. Marcelo Ackermann and Sylvia Spies (VU Amsterdam)
12:30 - 12:50 Sylvia Spies, PhD candidate, Biophotonics & Medical Imaging, VU Amsterdam
Titel: Rapid Assessment of Biopsies using Higher Harmonic Generation Microscopy
Abstract: Histopathology is the gold standard for cancer diagnosis. However, this technique is time-consuming and labor-intensive and cannot provide rapid feedback during clinical procedures. A rapid assessment of biopsies could help in decision making during biopsy procedures (or surgeries) and could create opportunity for a 'one-stop-shop', where diagnosis and treatment are combined into one procedure.
Higher harmonic generation (HHG) microscopy combines third harmonic generation (THG), second harmonic generation (SHG) and two- and three-photon excited autofluorescence (2PEF and 3PEF) to visualize cells, collagen, elastin and other fluorescent molecules, without any preparation or staining. Imaging is achieved within 1-3 seconds per field of view (400x400 μm), allowing a biopsy to be scanned in a few minutes.
We are performing multiple studies at the Amsterdam UMC, mainly on lung cancer, but also some other organs. HHG-imaging reveals histology-like architectural features and cellular details, while also providing complementary information such as clear differentiation between collagen and elastin. In addition, we are working on AI models to automatically analyze the images. Therefore, HHG has promising clinical applications and may even create opportunity for the ‘one-stop-shop’.
12:50 -13:45 Prof. Dr. Marcelo Ackermann, director ARCNL
Titel: Pushing for record reflectivity for soft X-ray and EUV multilayers
Abstract: EUV lithography had taken the world by storm. From ASML to NVIDIA – all rely on EUV technology to supply the world with ever more powerful chips to enable our hunger for data and AI. One of the key items in lithography are the combination of world leading light source (to make the photons) and optics (to transport the light and create an image on a wafer). The combination of both was probabaly one of the biggest challenges for EUV lithography. I will present the science and development of the EUV multilayer mirrors, with d-spacing in the range of a few nm are at the heart of modern EUV lithography equipment. Their reflectivity determines how much light gets reflected from the source to a wafer. The quality of the thin films making up the multilayer, but most importantly the sharpness of the interface between the layers is key to achieve high reflectivity. Roughness, intermixing and compound formation at these interfaces result in losses. In order to improve these interfaces, metrology is needed to resolve on the atomic level, what the driving mechanisms are that lead to reflectivity loss. At the sub-nm scale, a single technique is often insufficient to fully understand the physics of intermixing: Whereas TEM and XRR can resolve the local atomic or electronic density, XPS is optimal to highlight compound formation. We demonstrate that only a combination these techniques can truly resolve the interface. Using this knowledge on the nm-scale, we optimize the multilayer using diffusion barriers to limit intermixing and low energy ion polishing to minimize roughness, resulting in record reflectivities for EUV lithography at 13.5nm.