Enhanced reflectance of interface engineered Mo/Si multilayers produced by thermal particle deposition

Yakshin, Andrey; Kruijs, R. W. E. van de; Nedelcu, Ileana; Zoethout, E.; Louis, Eric; Bijkerk, F.; Enkisch, H.; Müllender, S.

doi:10.1117/12.711796

Cited by 37 publications

(28 citation statements)

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“…This is achieved by choosing a high contrast of the indices of refraction with simultaneously the lowest possible absorptivity, i.e., by maximizing the ratio Re( A − S )/ Im( A ). Indeed, choosing Mo as absorber material in Mo/Si multilayer mirrors maximizes this ratio, which is why Mo/Si mirrors provide the reflectivity record for multilayers at 13.5 nm wavelength [33].…”

Section: Anomalous Transmissionmentioning

confidence: 99%

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Narrowband and tunable anomalous transmission filters for spectral monitoring in the extreme ultraviolet wavelength region

et al. 2017

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We present the first experimental demonstration of a novel type of narrowband and wavelength-tunable multilayer transmission filter for the extreme ultraviolet (EUV) region. The operating principle of the filter is based on spatially overlapping the nodes of a standing wave field with the absorbing layers within the multilayer structure. For a wavelength with a matching node pattern, this increases the transmission as compared to neighboring wavelengths where anti-nodes overlap with the absorbing layers. Using Ni/Si multilayers where Ni provides strong absorption, we demonstrate the proper working of such anomalous transmission filter. The demonstration is carried out at the example of 13.5 nm wavelength and at normal incidence, providing a 0.27 nm-wide transmission peak. We also demonstrate wavelength tunability by operating the same Ni/Si filter at different wavelengths by varying the angle of incidence. As the multilayer filter is directly deposited on the active area of an EUV-sensitive photodiode, this provides an extremely compact device for easy spectral monitoring in the EUV. The transmission spectrum of the filter is modeled and found to be in good agreement with the experimental data. The agreement proves that such filters and compact monitoring devices can be straightforwardly designed and fabricated, as desired, also for other EUV wavelengths, bandwidths and angles of incidence, thereby showing a high potential for applications. (23), 3207-3212 (2004). 10. W. Schwanda, K. Eidmann, and M. C. Richardson, "Characterization of a flat-field grazing-incidence XUV spectrometer," J. X-Ray Sci. Technol. 4(1), 8-17 (1993). 11. N. Nakano, H. Kuroda, T. Kita, and T. Harada, "Development of a flat-field grazing-incidence XUV spectrometer and its application in picosecond XUV spectroscopy," Appl. Opt. 23 (14), 2386-2392 (1984 of free-standing, high-line-density transmission gratings for the vacuum UV to soft X-ray range," Opt. Express 23(4), 4421-4434 (2015).

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Section: Anomalous Transmissionmentioning

confidence: 99%

“…A more detailed discussion and choice of materials would therefore ultimately include also soft interfaces and diffusion barriers [33,41].…”

Section: Design Of An At Filter For 135 Nm Wavelengthmentioning

confidence: 99%

Narrowband and tunable anomalous transmission filters for spectral monitoring in the extreme ultraviolet wavelength region

et al. 2017

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“…The maximal theoretical reflectivity achieves ~76% at normal incidence. 5,6 Measured reflectivities of Mo/Si MXMs are known to be inferior to their theoretical values by 10−15 %. As the result in a multil-mirror optical system (for example, in EUV lithographs) the total performance would worsen dramatically.…”

Section: Introductionmentioning

confidence: 99%

The influence of working gas pressure on interlayer mixing in magnetron-deposited Mo/Si multilayers

et al. 2011

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Impact of Ar gas pressure (1−4 mTorr) on the growth of amorphous interlayers in Mo/Si multilayers deposited by magnetron sputtering was investigated by small-angle x-ray scattering (λ=0.154 nm) and methods of cross-sectional transmission electron microscopy. Some reduction of thickness of the amorphous inter-layers with Ar pressure increase was found, while composition of the layers was enriched with molybdenum. The interface modification resulted in raise of EUV reflectance of the Mo/Si multilayers.

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“…This allows for the use of ML mirrors with silicon spacers and high reflectivities. Indeed, Mo/Si ML mirrors have a theoretical reflectivity of 74 % and a value of 70.5 % has already been experimentally demonstrated [39]. Although this reflectivity is already very close to the theoretical maximum, up to eleven optical elements are used in the EUV imaging system resulting in a very low overall transmission of < 3 %.…”

Section: Euv Lithographymentioning

confidence: 99%

Single-order lamellar multilayer gratings

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Cover: 3D artist impression of a Lamellar Multilayer Grating (LMG). A Transmission Electron Microscope image of an actual LMG is shown on the rear. The grating was etched into a 400 bi-layer W/Si multilayer mirror with a total stack height H of 1 μm and a tungsten layer thickness of only 3 atoms. The grating had a period D of 300 nm and a lamel width ΓD of 75 nm. In comparison to the TEM image on the rear, the red and green layers in the artist impression correspond to tungsten and silicon, respectively. The bi-layer period in the artist impression is overestimated by a factor of 10 for visibility. SummaryA major challenge in the soft x-ray (SXR) and eXtreme UltraViolet (XUV) spectral ranges is the ability to manipulate the incident radiation using optical elements. By patterning conventional multilayer mirrors with nanoscale structures, novel optical elements with a variety of optical properties can be obtained. In this work, the design, fabrication and characterization of Lamellar Multilayer Gratings (LMG) was investigated. Such LMGs are a particular form of the general class of Bragg-Fresnel optics which combine Fresnel optics with Bragg reflection to provide unique dispersive and focusing optics. In particular, LMGs can be used to improve the spectral resolution of x-ray fluorescence techniques.A Coupled Waves Approach (CWA) was derived to simulate the optical performance, in terms of resolution and reflectivity, of LMGs. This CWA allowed to study the physical principles behind LMGs and resulted in the identification of an optimal LMG operating regime. In this regime, the incident beam is reflected in a single diffraction order and is hence referred to as the singleorder regime. Such single-order LMGs were fabricated using UV-NanoImprint Lithography and Bosch Deep Reactive Ion Etching, a process chosen to enable rapid practical development. Single-order operation was experimentally demonstrated and showed an improvement in spectral resolution of a factor of 3.8 with regard to conventional multilayer mirrors. Singe-order excitation of higher diffraction orders was also measured and analyzed.Single-order operation often requires multilayer stacks and grating structures that cannot be fabricated with sufficient accuracy using current technologies. As this invalidates the semi-infinite multilayer approximation, we investigated the optical performance of LMGs with finite multilayer stacks. We determined the ratio between the absorber thickness and bi-layer period of the multilayer stack can be used to further tailor LMG optical performance to maximize bandwidth reduction or minimize peak reflectivity loss. We also investigated various degradation processes that could limit the lifetime of LMGs, which is important for the applicability of such elements. Oxidation of tungsten and silicon as well as changes to the sidewall composition were clearly seen. However, SXR reflectivity remained stable to within measurement accuracy for an extended storage period of 18 months in a 1 atm air environment. The possibility of ...

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Enhanced reflectance of interface engineered Mo/Si multilayers produced by thermal particle deposition

Cited by 37 publications

References 0 publications

Narrowband and tunable anomalous transmission filters for spectral monitoring in the extreme ultraviolet wavelength region

Narrowband and tunable anomalous transmission filters for spectral monitoring in the extreme ultraviolet wavelength region

The influence of working gas pressure on interlayer mixing in magnetron-deposited Mo/Si multilayers

Single-order lamellar multilayer gratings

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