Thermal conduction properties of Mo/Si multilayers for extreme ultraviolet optics

Abstract

Enhanced leakage current performance and conduction mechanisms of Bi1.5Zn1.0Nb1.5O7/Ba0.5Sr0.5TiO3 bilayered thin films J. Appl. Phys. 112, 074113 (2012) In-operando and non-destructive analysis of the resistive switching in the Ti/HfO2/TiN-based system by hard xray photoelectron spectroscopy Appl. Phys. Lett. 101, 143501 (2012) Disorder induced semiconductor to metal transition and modifications of grain boundaries in nanocrystalline zinc oxide thin film J. Appl. Phys. 112, 073101 (2012) Control of normal and abnormal bipolar resistive switching by interface junction on In/Nb:SrTiO3 interface Appl. Phys. Lett. 101, 133506 (2012) Cross-plane electronic and thermal transport properties of p-type La0.67Sr0.33MnO3/LaMnO3 perovskite oxide metal/semiconductor superlattices Extreme ultraviolet (EUV) lithography requires nanostructured optical components, whose reliability can be influenced by radiation absorption and thermal conduction. Thermal conduction analysis is complicated by sub-continuum electron and phonon transport and the lack of thermal property data. This paper measures and interprets thermal property data, and their evolution due to heating exposure, for Mo/Si EUV mirrors with 6.9 nm period and Mo/Si thickness ratios of 0.4/0.6 and 0.6/0.4. We use time-domain thermoreflectance and the 3x method to estimate the thermal resistance between the Ru capping layer and the Mo/Si multilayers (R Ru-Mo/Si ¼ 1.5 m 2 K GW À1 ), as well as the out-of-plane thermal conductivity (k Mo/Si 1.1 W m À1 K À1 ) and thermal anisotropy (g ¼ 13). This work also reports the impact of annealing on thermal conduction in a co-deposited MoSi 2 layer, increasing the thermal conductivity from 1.7 W m À1 K À1 in the amorphous phase to 2.8 W m À1 K À1 in the crystalline phase. V C 2012 American Institute of Physics. [http://dx.

Focused helium and neon ion beam induced etching for advanced extreme ultraviolet lithography mask repair

“…15 Au, W, Ta, and TaN have also been investigated for absorber films. 16 Tantalum nitride (TaN) is the most commonly studied absorber layer; however, TaN spontaneously etches when exposed to XeF 2 during mask repair, thus requiring advanced passivation schemes. 17 Nickel has superior EUV absorption 2,3 over TaN and thus is being explored here as a candidate EUV absorber layer.…”

“…Because industrial applications require high mirror quality and lifetime, the kinetics of interdiffusion have been extensively characterized. 8,42,46 Importantly for stability of the mask, Bozorg-Grayeli et al 16 concluded that in a multilayer system such as Mo/Si, heat transfer and dissipation between layers is substantially degraded due to a thermal conductivity 100Â lower than for bulk values. This single fact may be responsible for enhanced silicidation at the interfaces.…”

In situ transformation and cleaning of tin-drop contamination on mirrors for extreme ultraviolet light

“…Our results show that sticking tin splats could be removed from large samples by phase conversion, independent of whether a coating with Mo/Si was present or not on the sample, whether a grating structure was etched on the surface or not, whether the sample was thin or thick. Even though the thermal transport from the solidified tin droplet to the bulk of the substrate is slightly impeded in the case of a coating with MLM as compared to bare Si wafers, 31 the tin splat sticking and cooling behavior can still be considered to be fairly similar for these sample types. Since the thermal properties describing the substrate effusivity e i 24 are not very different for crystalline Si and CVC-SiC (e Si = 15675 Ws 1/2 m -2 K -1 , e SiC = 19880 Ws 1/2 m -2 K -1 ), a quite similar transformation behavior may be expected for these substrate materials as well (for similar surface roughness) at the interface region with tin deposits.…”

Structural and Thermal Characterisation of Nanofilms by Time-Resolved X-ray Scattering

“…We explore the limits of the method of Time-domain X-ray thermal scattering (TDXTS, name given in analogy to TDTR) to investigate the cross-plane thermal conductivity of layered systems. Two extreme structures serve as showcases, on the one hand isotopically modulated silicon multilayers [25,30] and on the other hand Mo/Si ML, respectively silicide(SiMo)/Si multilayer (ML) [31,32]. While the first have an overall high conductivity and low interface defect density, the latter have a high acoustic impedance mismatch and (due to sputter growth) more defects.…”