Simulation of particle velocity in a laser-produced tin plasma extreme ultraviolet source

Abstract

In connection with fast heating in a laser produced plasma (LPP) extreme ultraviolet (EUV) source, the superheating behavior of bulk tin (Sn) at high heating rates is investigated. A constant temperature and pressure molecular dynamics simulation using modified Lennard-Jones and Coulomb potentials suitable for studying the liquid structure of Sn is employed in order to derive the caloric curves of the solid and liquid phases. The results have shown transient effects on the phase transitions. Superheating is observed during the melting and vaporizing processes. The velocity distribution of Sn particles against typical laser fluence in a LPP EUV light source has been numerically investigated using a simplified method including a one-dimensional, two-temperature, molecular dynamics, and steady-state ionization model. In the framework of our model, it was found that ejected Sn particles have a maximum velocity on the order of 10 to 40 km/ s in plasma created using a nanosecond pre-pulse neodymium-doped yttrium aluminum garnet (Nd:YAG, 1.06 lm) laser in EUV lithography experiments. V

Plasma Propulsion of a Metallic Microdroplet and its Deformation upon Laser Impact

“…For simplicity we take R to be constant during the duration of the pulse. From these considerations, we obtain the prediction F th ≈ 5 J cm −2 , identical to the ∼5 J cm −2 from plasma modeling [17]. This threshold laser fluence translates into a minimum necessary pulse energy.…”

“…In the present intensity regime, simulations predict v to range from 5-15 × 10 3 m/s [17] and to be a function of the laser intensity. Experimentally, v ≈ 8.5 × 10 3 m/s at a laser intensity of 2 × 10 11 W/cm 2 [7] which we take as a first estimate of the value for v in the following.…”

“…Here, the power α is taken as a free parameter since generally v = v(I) [17] and its scaling with intensity could influence the momentum scaling relation given by Eq. ( 4).…”

Drop fragmentation by laser-pulse impact

“…In the opaque tin and MEK drops (δ/R 0 1) direct laser-induced cavitation is unlikely. However, pressure transients resulting from the ablation and thermoelastic effects (Sigrist & Kneubühl 1978;Wang & Xu 2001;Vogel & Venugopalan 2003;Masnavi et al 2011) and shock waves accompanying plasma generation (Clauer, Holbrook & Fairand 1981;Marpaung et al 2001) travel through or may even focus inside the drop and induce potential cavitation spots (Reijers et al 2017).…”

Time and space resolved visible spectroscopic imaging CO2 laser produced extreme ultraviolet emitting tin plasmas

“…Recently, much effort has been devoted to developing an efficient and clean laser produced plasma (LPP) light source at 13.5 nm for next generation extreme ultraviolet (EUV) lithography in the semiconductor industries. [1][2][3] The strong unresolved transition arrays of tin centered near 13.5 nm offer a promising source of EUV radiation for the next generation of lithography. [4][5][6][7] Therefore, measurements of the plasma density and temperature are essential in order for us to obtain a better understanding of the tin plasma behavior over time and space, which is one of the keys to successfully producing the radiation source, as well as offering a reference for numerical simulations used to study and optimize these phenomena.…”