A5053679248- Laser-induced spectroscopy and plasma
- Laser-Matter Interactions and Applications
- Atomic and Molecular Physics
- Laser-Plasma Interactions and Diagnostics
- Laser Material Processing Techniques
- Fluid Dynamics and Heat Transfer
- Laser-Ablation Synthesis of Nanoparticles
- Electrohydrodynamics and Fluid Dynamics
- Planetary Science and Exploration
- Diamond and Carbon-based Materials Research
- Ion-surface interactions and analysis
- Ionosphere and magnetosphere dynamics
- Ocular and Laser Science Research
- Mass Spectrometry Techniques and Applications
- Laser Design and Applications
- Plasma Diagnostics and Applications
- Solar and Space Plasma Dynamics
- Pickering emulsions and particle stabilization
ASML (Netherlands)
2020-2022
Advanced Research Center for Nanolithography (Netherlands)
2016-2021
Vrije Universiteit Amsterdam
2016-2020
Shining a short, intense laser pulse on micrometer-sized droplets of liquid metal creates plasma that is bright source extreme ultraviolet (EUV) light. The authors study in detail the propulsion and deformation such due to ``kick'', unveil underlying mechanisms scaling laws. Optimizing EUV sources for next-generation nanolithography requires deep understanding both droplet-laser coupling droplet fluid-dynamical response, which this work provides.
Plasmas produced from microdroplets of liquid tin provide light at an extreme ultraviolet (EUV) wavelength 13.5 nm, for state-of-the-art nanolithography that will enable the continuation Moore's law in shrinking transistors. Currently CO${}_{2}$ gas lasers are used to drive such plasma; transitioning modern solid-state would have significant advantages, if efficiency converting laser energy into 13.5-nm radiation were sufficiently competitive. This study quantifies solid-state-laser-driven...
The measurement of the propulsion metallic microdroplets exposed to nanosecond laser pulses provides an elegant method for probing ablation pressure in a dense laser-produced plasma. We present measurements velocity over three decades driving Nd:YAG pulse energy and observe near-perfect power law dependence. Simulations performed with RALEF-2D radiation-hydrodynamic code are shown be good agreement above specific threshold energy. simulations highlight importance radiative losses which...
We study the fragmentation of a liquid drop that is hit by laser pulse. The expands into thin sheet breaks radial expulsion ligaments from its rim and nucleation growth holes on sheet. By combining experimental data two systems with vastly different time- length scales we show how early-time laser-matter interaction affects late-time fragmentation. identify Rayleigh--Taylor instabilities origins as prime cause derive scaling laws for characteristic breakup time wavenumber. final web results...
We experimentally and numerically investigate the early-time hydrodynamic response of tin microdroplets driven by a ns-laser-induced plasma. Experimentally, we use stroboscopic microscopy to record laser-induced dynamics liquid droplets determine propulsion speed $(U)$ initial radial expansion rate $({\stackrel{\ifmmode \dot{}\else \.{}\fi{}}{R}}_{0})$. The ratio these two quantities is key parameter be optimized for applications in nanolithography, where laser-impacted serve as targets...
Experimental scaling relations of the optical depth are presented for emission spectra a tin-droplet-based, 1-μm-laser-produced plasma source extreme-ultraviolet (EUV) light. The observed changes in complex spectral over wide range droplet diameters (16–65 μm) and laser pulse durations (5–25 ns) accurately captured relation featuring as single, pertinent parameter. scans were performed at constant intensity 1.4 × 1011 W/cm2, which maximizes 2% bandwidth around 13.5 nm relative to total...
Ion energy distributions arising from laser-produced plasmas of Sn are measured over a wide laser parameter space. Planar-solid as well liquid-droplet targets exposed to infrared pulses with densities between 1J/cm$^2$ and 4kJ/cm$^2$ durations spanning 0.5ps 6ns. The ion compared two self-similar solutions hydrodynamic approach assuming isothermal expansion the plasma plume into vacuum. For planar droplet ps-long we find good agreement experimental results solution semi-infinite simple...
We experimentally study the morphology of a radially expanding sheet liquid tin, formed by nanosecond-pulse Nd:YAG laser impact on spherical microdroplet. Specifically, thickness profile and its time evolution are captured in detail over range laser-pulse energies for two droplet sizes. Two complementary methods to determine this employed shown be excellent agreement. All obtained profiles collapse onto single self-similar curve. Spatial integration allows us volume sheet. Remarkably, less...
We experimentally study the mass distribution of a sheet liquid tin formed by impact ns-laser pulse on spherical microdroplet. The is obtained using low-intensity, second pulse, which induces vaporization stretching thin sheet. This careful enables investigation thickness profile sheet, and its mass, at early times after laser droplet, have remained inaccessible methods used in recent work [B. Liu et al., Phys. Rev. Appl. 13, 024035 (2020)]. method, moreover, allows visualization thick rim...
We present the results of spectroscopic measurements in extreme ultraviolet regime (7–17 nm) molten tin microdroplets illuminated by a high-intensity 3 J, 60 ns Nd:YAG laser pulse. The strong 13.5 nm emission from this laser-produced plasma (LPP) is relevance for next-generation nanolithography machines. Here, we focus on shorter wavelength features between 7 and 12 which have so far remained poorly investigated despite their diagnostic relevance. Using flexible atomic code calculations...
We experimentally study the interaction of intense laser pulses with metallic microdroplets and resulting deformation. Two main droplet deformation regimes have previously been established: that sheet-type expansion after impact “long” (typically >10 ns) governed by incompressible flow spherical internal cavitation “short” <100 ps) shock waves, i.e., strongly compressible flow. In this work, we transition between these scanning pulse durations from 0.5 to 7.5 ns, where...
The cavitation-driven expansion dynamics of liquid tin microdroplets is investigated, set in motion by the ablative impact a 15-ps laser pulse. We combine high-resolution stroboscopic shadowgraphy with an intuitive fluid dynamic model that includes onset fragmentation, and find good agreement between experimental data for two different droplet sizes over wide range pulse energies. dependence initial velocity on these parameters heuristically captured single power law. Further, obtained...
Abstract In this work, the expansion dynamics of liquid tin micro-droplets irradiated by femtosecond laser pulses were investigated. The effects pulse duration, energy, and polarization on ablation, cavitation, spallation studied using durations ranging from 220 fs to 10 ps, with energies 1 5 mJ, for an initial radius 15 23 $$\upmu$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>μ</mml:mi></mml:math> m. Using linearly polarized pulses, cylindrically asymmetric shock waves...
The effect of a pair picosecond pulses on the ionization and deformation liquid tin microdroplet is studied for range incident pulse parameters. Faraday cups are used to measure ion kinetic energy distributions, together with high-resolution shadowgraphy monitor target expansion. It found that introduction relatively weak first results in an order-of-magnitude reduction number ions energies above 1 keV, strong shift distribution towards lower energies, while expansion dynamics droplet can be...
Laser-produced Sn plasma sources are used to generate extreme ultraviolet (EUV) light in state-of-the-art nanolithography. An and optical spectrum is measured from a droplet-based laser-produced plasma, with spectrograph covering the range 200 - 800 nm. This contains hundreds of spectral lines lowly charged tin ions Sn$^{1+}$ Sn$^{4+}$ which major fraction was hitherto unidentified. We present identify selected class belonging quasi-one-electron, Ag-like ([Kr]$4d^{10} nl$ electronic...
We present and experimentally validate a model describing the sensitivity of tilt angle, expansion, propulsion velocity tin micro-droplet irradiated by 1 μm Nd:YAG laser pulse to its relative alignment. This is particularly relevant in industrial plasma sources extreme ultraviolet light for nanolithographic applications. Our has but single parameter: dimensionless ratio spot size effective droplet, which related position critical density surface. enables development straightforward scaling...
Abstract The laser ablation threshold is an important parameter that governs the response of materials to intense irradiation. Here we study liquid tin, by irradiating tin microdroplets with nanosecond pulses having finely controlled temporal shape and duration. We use time-dependent reflection from droplet as main observable, which exhibits a sharp decrease in magnitude at given time instance depends on intensity. This moment marks generation plasma strongly absorbs following incident...
Laser-induced cavitation in tin microdroplets can be used to obtain optimized laser targets EUV sources for nanolithography. We present our experimental analysis of microdroplet expansion and find good agreement with a fluid dynamics model.
Laser-produced tin plasmas are used for the generation of extreme ultraviolet light nanolithography. We use an extensive diagnostic toolset to characterize and understand physics these plasma sources at atomic level.
At ARCNL, we have built a picosecond Nd:YAG laser system with pulse duration tunable between 15 and 110 ps, delivering up to 175 mJ at 100 Hz repetition rate. Furthermore, set an OPCPA pumped by this ps laser, which provides 220 fs pulses 1.5 μm wavelength 12.5 energy. These systems were used produce tin plasmas from solid flat target as well liquid micro-droplets, the goal of understanding ion emission laser-produced (LPP), ablation dynamics laser-induced droplet deformation.
Synopsis Highly charged tin ions are the sources of extreme ultraviolet (EUV) light at 13.5-nm wavelength in laser-produced transient plasmas for next-generation nanolithography. Generating this EUV required power, reliability, and stability however presents a formidable task that combines industrial innovations with challenging scientific questions. We will present work on spectroscopy out YAG-laser-driven plasma surprising answer to key question: what makes light?
We describe a laser system capable of delivering ~450 mJ pulses with arbitrarily tunable temporal shapes. show how this shaping affects target deformation and EUV generation when these illuminate liquid tin droplets.