Greifswald 2024 – scientific programme

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P: Fachverband Plasmaphysik

P 25: Poster III

P 25.7: Poster

Thursday, February 29, 2024, 16:30–18:30, ELP 6: Foyer

The STØR experiment - a spherical toroidal magnetic confinement concept applied as a radiation source — •Nils Fahrenkamp, Sebastian Haag, Stefan Knauer, and Peter Manz — Institute of Physics, University of Greifswald, Greifswald, Germany

Extreme Ultraviolet (EUV) lithography is a crucial technology nowadays. EUV light is used to project high-resolution patterns onto silicon wafers, enabling the production of smaller and more powerful microchips. At the desired wavelength lasers are no longer available as light sources, so plasma sources have to be used. They need to generate extremely high power emitted in a very narrow spectral band around 13.5 nm (± 0.135 nm, the so-called in-band) in a small source volume necessary for efficient radiation. Laser-produced plasmas (LPPs) prevailed because the discharge-produced plasmas (DPPs) did not achieve the desired parameters of n_e∼ 10²⁴ m⁻³ and T_e∼ 30 eV. Current state-of-the-art sources use laser irradiated tin (Sn) droplets as emitter because it has strong in-band emission. But a single unit weighs over 180 tons, consumes more than 1 MW electrical power and costs more than 100 million dollars. The inevitable high cost of LPPs means that low-cost or table-top systems will continue to rely on DPPs. Alternative magnetic confinement concepts are particularly well suited as radiation sources, as they contribute to reducing costs and improving accessibility for various research institutions. We present here an experimental setup allowing for magnetically confined compact plasma tori without external toroidal and poloidal magnets. These are ideal properties for a radiation source.

Keywords: EUV; lithography; radiation source; torus