6 December 2004 Absorber stack optimization toward EUV lithography mask blank pilot production
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EUV Lithography requires high end quality defect free layers from the backside coating to the absorber stack. Low thermal expansion materials (LTEM) substrates with super flat surfaces are already available with low defect backside coating for E-Chuck technology. The multilayer stack is well developed from a physical point of view and major effort relies nowadays on the layer defectivity. On the other hand, absorber stack becomes one of the main challenges in terms of stress, optical behavior for ultraviolet wavelengths and dry etching behavior. Schott Lithotec is currently developing absorber stack solutions that will fulfill the requirements of next generation lithographies. There are several options for achieving the mechanical, optical and chemical specs for buffer layers and absorber coatings. Some of them are already integrated in our production processes. Buffer layers were evaluated and reach almost the physical and chemical level necessary to fit with the mask processing. TaN based absorber coatings were designed and deposited by an ion beam sputter tool optimized for low defect deposition (LDD-IBS). The chemical composition of our layer and its manufacturing process is already optimized to achieve high quality etching behavior. The current results of defect density for the absorber stack will be presented.
© (2004) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Frank Sobel, Lutz Aschke, Markus Renno, Holger Seitz, Hans Willy Becker, Nathalie Olschewski, Torsten Reichardt, Guenter Hess, Ute Buttgereit, Konrad Knapp, Florian Letzkus, Joerg Butschke, and Corinna Koepernik "Absorber stack optimization toward EUV lithography mask blank pilot production", Proc. SPIE 5567, 24th Annual BACUS Symposium on Photomask Technology, (6 December 2004); doi: 10.1117/12.568787; https://doi.org/10.1117/12.568787


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