Physical processes in EUV sources for microlithography

Banine, VY Vadim; Koshelev, K. N.; Swinkels, Geert

doi:10.1088/0022-3727/44/25/253001

Cited by 199 publications

(169 citation statements)

References 71 publications

Supporting

Mentioning

166

Contrasting

Unclassified

Order By: Relevance

“…The tin spectra provide a useful benchmark for the EUV performance of the galinstan plasmas, under the same range of conditions. The tin spectra show the expected UTA in the range of 13-15 nm as has been reported for both discharge [3][4][5]11 and LPP 12,13 sources. For galinstan, the tin UTA is also observed, but transitions in the range of 11.5-13 nm, due to gallium, and 14-18 nm, due to both gallium and indium, are also present.…”

supporting

confidence: 80%

“…3 EUV emission from a Z-pinch in a laser-triggered discharge between rotating electrodes coated with liquid tin has been studied previously. 4,5 The liquid metal coating overcomes the problem of electrode erosion, but it is necessary to maintain the tin above its melting temperature of 232 C. The EUV emission spectrum of pure tin plasma, at the appropriate conditions, is relatively narrow-band, with $50% of emission in the 13-15 nm range. For EUV metrology, the source parameters of interest are spectral radiance, wavelength range, and emission uniformity, as well as cost and ease of operation.…”

mentioning

confidence: 99%

“…The source was developed at the Russian Institute of Spectroscopy (ISAN). 5 Figure 1 shows plan and side views of the electrode geometry and the arrangement of the diagnostic instruments. The disc electrodes are tilted so that the separation at closest approach is 4 mm.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Laser triggered Z-pinch broadband extreme ultraviolet source for metrology

Tobin

Juschkin

Sidelnikov

et al. 2013

Applied Physics Letters

View full text Add to dashboard Cite

We compare the extreme ultraviolet emission characteristics of tin and galinstan (atomic %: Ga: 78.35, In: 14.93, Sn: 6.72) between 10 nm and 18 nm in a laser-triggered discharge between liquid metal-coated electrodes. Over this wavelength range, the energy conversion efficiency for galinstan is approximately half that of tin, but the spectrum is less strongly peaked in the 13–15 nm region. The extreme ultraviolet source dimensions were 110 ± 25 μm diameter and 500 ± 125 μm length. The flatter spectrum, and −19 °C melting point, makes this galinstan discharge a relatively simple high radiance extreme ultraviolet light source for metrology and scientific applications.

show abstract

supporting

confidence: 80%

mentioning

confidence: 99%

See 1 more Smart Citation

Laser triggered Z-pinch broadband extreme ultraviolet source for metrology

Tobin

Juschkin

Sidelnikov

et al. 2013

Applied Physics Letters

View full text Add to dashboard Cite

show abstract

“…An important application of drop deformation by laser-pulse impact is found in laserproduced plasma light-sources for extreme ultraviolet (EUV) nanolithography. In these sources a nanosecond laser pulse pre-shapes a falling liquid tin drop into a thin sheet, which is subsequently ionized by a second laser pulse (Mizoguchi et al 2010;Banine et al 2011). To maximize the conversion of liquid tin to plasma a precise control of the drop shape and stability that result from the first laser impact is crucial.…”

Section: Introductionmentioning

confidence: 99%

Drop deformation by laser-pulse impact

et al. 2016

View full text Add to dashboard Cite

A free-falling absorbing liquid drop hit by a nanosecond laser-pulse experiences a strong recoil-pressure kick. As a consequence, the drop propels forward and deforms into a thin sheet which eventually fragments. We study how the drop deformation depends on the pulse shape and drop properties. We first derive the velocity field inside the drop on the timescale of the pressure pulse, when the drop is still spherical. This yields the kinetic-energy partition inside the drop, which precisely measures the deformation rate with respect to the propulsion rate, before surface tension comes into play. On the timescale where surface tension is important the drop has evolved into a thin sheet. Its expansion dynamics is described with a slender-slope model, which uses the impulsive energy-partition as an initial condition. Completed with boundary integral simulations, this two-stage model explains the entire drop dynamics and its dependance on the pulse shape: for a given propulsion, a tightly focused pulse results in a thin curved sheet which maximizes the lateral expansion, while a uniform illumination yields a smaller expansion but a flat symmetric sheet, in good agreement with experimental observations. IntroductionA laser pulse interacting with an absorbing liquid body can deposit a finite amount of energy, concentrated both in time and space, which eventually triggers a dramatic hydrodynamic response. Focused nanosecond pulses have for instance been used to induce cavitation in liquids confined in capillary tubes (Vogel et al. 1996;Sun et al. 2009;Tagawa et al. 2012), or jetting and spraying in sessile drops (Thoroddsen et al. 2009). These situations involving a liquid close to a wall result in localized flows. By contrast, we consider here the situation of a mobile liquid body: the impact of a nanosecond laser pulse onto an absorbing unconfined liquid drop, which, as first described by Klein et al. (2015), has a global hydrodynamic response to the pulse: the drop propels forward at a speed of several meters per second, strongly deforms and eventually fragments (see Fig. 1). This dynamics is similar to that following a mechanical impact such as on a solid substrate or a pillar, which has been studied thoroughly (see e.g. Clanet et al. 2004;Yarin 2006;Villermaux & Bossa 2011;Kolinski et al. 2012;Riboux & Gordillo 2014;Josserand & Thoroddsen 2016), including a few studies on the fragmentation of the drop (Villermaux 2007;Xu et al. 2007;Villermaux & Bossa 2009, 2011Riboux & Gordillo 2014). A laser proves to be an adequate tool to vary the extension of the impact without arXiv:1512.02415v1 [physics.flu-dyn] 8 Dec 2015

show abstract

“…The search for the optimum radiation source at 13.5 nm for extreme ultraviolet lithography (EUVL) has been the subject of intense research activity in recent years [1,2]. These studies have shown that plasmas containing tin, where transitions of the type 4p 6 4d n -4p 5 4d n+1 + 4d n-1 4f overlap in ion stages from Sn 9+ -Sn 13+ to form an unresolved transition array (UTA) centered near 13.5 nm are the strongest emitters at this wavelength.…”

mentioning

confidence: 99%

Gd plasma source modeling at 6.7 nm for future lithography

Dunne

Higashiguchi

et al. 2011

Applied Physics Letters

View full text Add to dashboard Cite

Plasmas containing gadolinium have been proposed as sources for next generation lithography at 6.x nm. To determine the optimum plasma conditions, atomic structure calculations have been performed for Gd11+ to Gd27+ ions which showed that n = 4 − n = 4 resonance transitions overlap in the 6.5–7.0 nm region. Plasma modeling calculations, assuming collisional-radiative equilibrium, predict that the optimum temperature for an optically thin plasma is close to 110 eV and that maximum intensity occurs at 6.76 nm under these conditions. The close agreement between simulated and experimental spectra from laser and discharge produced plasmas indicates the validity of our approach.

show abstract

Physical processes in EUV sources for microlithography

Cited by 199 publications

References 71 publications

Laser triggered Z-pinch broadband extreme ultraviolet source for metrology

Laser triggered Z-pinch broadband extreme ultraviolet source for metrology

Drop deformation by laser-pulse impact

Gd plasma source modeling at 6.7 nm for future lithography

Contact Info

Product

Resources

About