Combined EUV reflectance and X-ray reflectivity data analysis of periodic multilayer structures

Abstract

We present a way to analyze the chemical composition of periodical multilayer structures using the simultaneous analysis of grazing incidence hard X-Ray reflectivity (GIXR) and normal incidence extreme ultraviolet reflectance (EUVR). This allows to combine the high sensitivity of GIXR data to layer and interface thicknesses with the sensitivity of EUVR to the layer densities and atomic compositions. This method was applied to the reconstruction of the layered structure of a LaN/B multilayer mirror with 3.5 nm periodicity. We have compared profiles obtained by simultaneous EUVR and GIXR and GIXR-only data analysis, both reconstructed profiles result in a similar description of the layered structure. However, the simultaneous analysis of both EUVR and GIXR by a single algorithm lead to a ∼ 2x increased accuracy of the reconstructed layered model, or a more narrow range of solutions, as compared to the GIXR analysis only. It also explains the inherent difficulty of accurately predicting EUV reflectivity from a GIXR-only analysis.

Multiparameter characterization of subnanometre Cr/Sc multilayers based on complementary measurements

“…With the efforts to reduce the peak reflectance wavelength, those methods fail to yield consistent information in the framework of simple models that describe the measured reflectivities. This has already been observed in the case of La/ B multilayer mirrors designed for peak reflectivities at 6.7 nm wavelength (Yakunin et al, 2014).…”

Surface structure determination by x-ray standing waves at a free-electron laser

“…The data analysis consisted of several steps and to facilitate their comprehension a visual representation is given by the flowchart in figure 7. First, using the assumption independent approach [50] GIXR measurements from sample 2 with 1 Si x interlayers, and sinusoidal transition layers between them for the simultaneous fit of GIXR and EUVR data as described in [51]. Second, the data of samples 1, 3, and 4 were fitted using the same 49 Mo/Si bilayers derived from sample 2.…”

Experimental study of EUV mirror radiation damage resistance under long-term free-electron laser exposures below the single-shot damage threshold

“…conclusions on the nature of the changes of the structure of the analysed samples (Yakunin et al, 2014;Haase et al, 2016). Therefore, additional characterization techniques are needed for combined analysis.…”