Resolution and throughput scalability limits of a compact EUV nanopatterning tool - Erkenntnistransfer-Projekt
Synthesis and Properties of Functional Materials
Final Report Abstract
The ongoing development of nanotechnologies in recent years has opened various possibilities for new applications in which periodic nanostructures with a critical dimension below 10 nm are required. Applications can be found in various research areas (pre-patterning of substrates for e.g., 3D quantum dot crystals, growth of nanowires or alignment of block copolymers) as well as in industrial extreme ultraviolet (EUV) lithography (characterization of photoresists). The focus can be on either the ultimate structure size and its periodicity/density, on the total area to be patterned (in the range of several cm²), or on both aspects. For this application, a compact nanopatterning tool using EUV radiation was realized at the Chair TOS of RWTH Aachen University and the fabrication of periodic nanostructures down to sub-30 nm half-period was demonstrated. The facility uses a compact gas discharge-produced plasma source (DPP), which is being developed at Fraunhofer ILT in Aachen. However, further knowledge regarding the achievable resolution and throughput is necessary for the application of the patterning technology in an industrial prototype system. During the project, the scaling limits of the technology with respect to resolution and throughput were therefore investigated both theoretically and experimentally. The transmission masks required to generate a nano-scaled intensity modulation were optimized using rigorous wave-optical simulations, and the influence of mask geometry and material selection on the achievable theoretical resolution was investigated. Several alternative materials for use in transmission masks were identified that contribute to a resolution enhancement. In addition, the influence of the partially coherent radiation from the used EUV source on the resolution was considered. Mask fabrication was optimized based on the obtained findings and the limitations of current mask technology in terms of resolution and throughput were investigated. To increase the throughput, an efficient illuminator was designed as a multilayer mirror with high reflectivity, which collects a larger solid angle of the emitted EUV radiation from the source and collimates it into the exposure plane. In addition, the hardware and software limitations of the current setup were investigated and documented. To conclude the project, high-resolution EUV photoresists were characterized in terms of contrast and sensitivity and nanopatterned using the fabricated transmission masks. Here, the currently existing resolution limit of the structure of 28 nm half-period for hole arrays and 32.5 nm halfperiod for line arrays was determined. The latter currently represents the record resolution for line arrays using Talbot lithography. The knowledge gained from the project is being used to formulate design rules for an industrial prototype system. Alternative mask materials and mask designs have been developed that can contribute to resolution enhancement down to sub-10 nm half-period. The designed illumination optics will lead to a throughput increase of an optimized system by a factor of ~3. In addition, the stability and positioning accuracy of the mask-wafer positioning system was identified as a limiting factor and an optimized arrangement of components was designed.
Publications
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Design and realization of an industrial stand-alone EUV resist qualification setup. Extreme Ultraviolet Lithography 2020, 53. SPIE.
Lüttgenau, Bernhard; Brose, Sascha; Choi, Seonghyeok; Panitzek, Dieter; Danylyuk, Serhiy; Lebert, Rainer; Stollenwerk, Jochen & Loosen, Peter
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Novel high-contrast phase-shifting masks for EUV interference lithography. Extreme Ultraviolet (EUV) Lithography XI, 57. SPIE.
Lüttgenau, Bernhard; Brose, Sascha; Danylyuk, Serhiy; Stollenwerk, Jochen & Loosen, Peter
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Design and realization of an in-lab EUV dual beamline for industrial and scientific applications. International Conference on Extreme Ultraviolet Lithography 2021, 21. SPIE.
Lüttgenau, Bernhard; Brose, Sascha; Danylyuk, Serhiy; Stollenwerk, Jochen; Loosen, Peter & Holly, Carlo
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Design of an efficient illuminator for partially coherent sources in the extreme ultraviolet. Applied Optics, 61(11), 3026.
Lüttgenau, Bernhard; Panitzek, Dieter; Danylyuk, Serhiy; Brose, Sascha; Stollenwerk, Jochen; Loosen, Peter & Holly, Carlo
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Towards the resolution limit of Talbot lithography with compact EUV exposure tools. International Conference on Extreme Ultraviolet Lithography 2022, 13. SPIE.
Lüttgenau, Bernhard; Brose, Sascha; Danylyuk, Serhiy; Stollenwerk, Jochen & Holly, Carlo
