Developments of a high-power, low-contamination laser-plasma source for EUV projection lithography

Shmaenok, L. A.; Bijkerk, F.; Bruineman, C.; Bastiaensen, R. K. F. J.; Shevelko, A. P.; Simanovski, Dmitrii M.; Gladskikh, A. N.; Bobashev, S. V.

doi:10.1117/12.220971

Cited by 6 publications

(3 citation statements)

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“…All experiments were performed at the laser plasma source and EUV imaging facility at the FOM Institute for Plasma Physics Rijnhuizen [4,7]. To generate the plasmas, an application-speciÐc KrF laser (Lambda Physik LPX350cc) was employed in the injection-locked mode of operation.…”

Section: Methodsmentioning

confidence: 99%

“…Absolute calibration of the spectrograph was performed by direct comparison of the spectral intensity at j \ 13.5 nm with absolute intensity measurements using a technique with multilayer mirror and an XUV p-i-n diode as a detector (Fig. 1) [4,10]. The spherical Mo/Si multilayer mirror (2d-spacing \13.5 nm, spectral selectivity j/*j \ 25) monochromatized the broadband plasma radiation and directed the radiation to the detector.…”

Section: Methodsmentioning

confidence: 99%

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Extreme Ultraviolet Spectroscopy of a Laser Plasma Source for Lithography

et al. 1998

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Spectra from various target materials from a KrF-laser plasma source have been investigated in the Extreme UV spectral range between 12 and 17nm using an off-Rowland grazing-incidence spectrograph. The electron temperature Te and mean ionization stages Z have been measured to amount to Te = 80eV and Z = 10–12, respectively. Additional calibration and measurement of the spatial and temporal characteristics of the plasma has been done using a combination of a multilayer mirror and XUV diode or fiber image carrier system. The maximum yield at 13.5nm (2.4–3 × 1015 phot/srnm) has been observed for targets with atomic number Za = 32, 50, 73–75, of which the radiative transitions have been identified as 3p–3d, 4d–4f and 4f–5d transitions respectively. The corresponding maximum conversion efficiency at 13.5nm was 0.43% in a 1% bandwidth. An option for further optimization of the KrF laser plasma source for application in EUV lithography is discussed.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Extreme Ultraviolet Spectroscopy of a Laser Plasma Source for Lithography

et al. 1998

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“…One of the most important and challenging problems facing the extreme ultraviolet lithography (EUVL) community at present is the choice of a stable, debris free and high efficiency plasma source for use at soft x-ray wavelengths of 13.5 nm. This wavelength regime has approximately 71% reflectivity for Mo/Si multilayer coated optics [1] and so is the preferred choice for the next generation of Extreme Ultraviolet Technologies [2][3][4].…”

Section: Introductionmentioning

confidence: 99%

Conversion efficiency of a laser-produced Sn plasma at 13.5 nm, simulated with a one-dimensional hydrodynamic model and treated as a multi-component blackbody

Cummings¹,

O'Sullivan²,

Dunne³

et al. 2005

J. Phys. D: Appl. Phys.

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Efficiency optimization of a stable and debris free plasma source at 13.5 nm, is at the forefront of current extreme ultraviolet lithographic (EUVL) research efforts. To date, 1–2.5% soft x-ray conversion efficiencies (CEs) within a 2% bandwidth (BW) around 13.5 nm and into 2π steradians have been attained experimentally for laser-produced plasmas containing Sn at power densities of 0.5–5 × 1011 W cm−2. In order to complement these experimental endeavours, we have undertaken to study the CE, for the given wavelength regime, in the optically thick limit. We have achieved this by coupling time-dependent and steady-state collisional-radiative (CR) equations to the output of the one-dimensional hydrodynamic code MED103 (MEDUSA), where a solid sphere of radius 50 µm was uniformly irradiated by a high intensity laser pulse with a Gaussian temporal profile. The ion populations obtained from these CR results were then used in an integrated spatio-temporal figure of merit (FOM) together with in-band weighted dipole oscillator strengths and transition energies. The maximum FOM, when divided by the laser energy, was found to occur in the range of peak power densities of 2–3 × 1011 W cm−2 for the steady-state and time-dependent models, respectively. The hydrodynamic variables of these peak power densities were then used in a radiative transfer calculation in which the many-celled spherical plasma was treated as a multi-component blackbody. It is found that CEs of 3.5–6% within the 2% BW per 2π steradians may be achieved. These results are of particular relevance to EUVL technologies where a minimum CE of 3% is required by industry.

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