Abstract
The aim of this Thesis is to experimentally investigate and understand plasmas as used in extreme ultraviolett (EUV) lithography, and learn what conversion efficiencies (CE) and which in-band energies can be achieved by irradiating tin targets
with 2-μm-wavelength laser light. To do so, we built a 2-μm-wavelength system, based
on the parametric conversion of 1-μm- into 2-μm-wavelength, and applied it in our
investigations of EUV light generation. This laser system is not envisioned to be used
in any industrial application since it runs at a low 10 Hz repetition rate, but it is valuable
as a first plasma driver to characterize the EUV emission from 2-μm-wavelength
driven tin plasmas. Our studies include a comparison of 1-μm- and 2-μm-driven
plasmas to gain insight on how the expected reduction in optical depth affects the
CE and obtainable overall in-band energy. This insight is valuable to characterize
and understand the effects of different laser irradiation parameters (i.e., laser intensity,
laser pulse duration, laser beam spot size, and intensity distribution) and tin target
morphology. We systematically investigate how the in-band energy that could be used
in EUVL scales with laser irradiation parameters and tin target size. The goal is to
determine if the in-band energy could be scaled to energy levels relevant to the industry
without impairing the CE. Showing high obtainable CEs from 2-μm-wavelength driven
EUV plasma close to those from the CO2-gas laser, at relevant in-band energies would
be a critical first step towards demonstrating the feasibility to enhance the overall energy efficiency of EUV sources by using 2-μm solid-state-lasers.
Original language | English |
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Qualification | PhD |
Awarding Institution |
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Supervisors/Advisors |
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Award date | 2 Oct 2023 |
Print ISBNs | 9789464833768 |
DOIs | |
Publication status | Published - 2 Oct 2023 |
Keywords
- EUV, Source, lithography, plasma, laser, high energy, tin target,