Microdroplet-tin plasma sources of EUV radiation driven by solid-state-lasers (Topical Review)

Abstract

Plasma produced from molten-tin microdroplets generates extreme ultraviolet light for state-of-the-art nanolithography. Currently, CO2 lasers are used to drive the plasma. In the future, solid-state mid-infrared lasers may instead be used to efficiently pump the plasma. Such laser systems have promise to be more compact, better scalable, and have higher wall-plug efficiency. In this Topical Review, we present recent findings at the Advanced Research Center for Nanolithography (ARCNL) on using 1- and 2-µm-wavelength solid-state lasers for tin target preparation and for driving hot and dense plasma. The ARCNL research ranges from advanced laser development, over studies of fluid dynamic response of droplets to impact, radiation-hydrodynamics calculations of, e.g., ion “debris”, (EUV) spectroscopic studies of tin laser-produced-plasma, to high-conversion efficiency operation of 2-µm-wavelength driven plasma.

Ultrafast serrodyne optical frequency translator

“…Furthermore, nonlinear spectroscopy methods and applications that use secondary laser-driven high harmonic sources as, for example, attosecond science could greatly benefit from continuously tunable extreme ultraviolet sources driven by wavelength-tunable lasers. Furthermore, applications demanding highest peak or average power lasers such as laser plasma acceleration 34 or semiconductor chip production 3 , which were so far constrained to a single or very few operation points in the electromagnetic spectrum, will benefit from novel optimization opportunities. Finally, the here-presented ultrafast serrodyne optical frequency-shifting scheme can prospectively be extended to other MPC input pulse shapes optimized for targeted output spectra, including spectra exhibiting, for example, two separated peaks or a defined output bandwidth.…”

“…An important part of this progress can be attributed to advances in ultrafast high peak and/or average power laser technology. High-power lasers opened a path to capture subfemtosecond electron dynamics 1 , they have enabled great insights into the proton structure 2 and the development of suitable tools for next-generation chip manufacturing via short-wavelength nanolithography 3 . Dedicated laser parameters are required for many innovations and applications, including application-optimized wavelength, intensity, pulse length, beam properties and many more.…”

Gas temperature measurement by atomic line broadening using the LIBS technique

“…9,10 The breakdown process is independent of the type and state of the target, so the LIBS technique can be widely used to analyze solids, liquids, and gases. [11][12][13][14] The LIBS signal is highly responsive and robust enough to overcome many optical interferences, even in sooty ames, which is of particular interest in rapidly changing turbulent ames. 15 These advantages mean that LIBS should also be further developed and applied in temperature measurement.…”

Characteristics of tin droplet target system for EUV source research

“…The operating principle of this droplet generator (DG) device can be explained by the Rayleigh-Plateau instability theory [9][10][11][12][13]. With the interaction between high-power CO 2 laser and tin-droplets, high-intensity EUV emission with a central wavelength of 13.5 nm and 2% bandwidth can be derived [14,15]. Under this background, it puts high requirements on the uniformity and stability of tin droplets.…”