Mirror contamination and secondary electron effects during EUV reflectivity analysis
29 Mar 2012-Proceedings of SPIE (International Society for Optics and Photonics)-Vol. 8322, pp 832233
TL;DR: In this article, the angular dependency of XPS peak area intensity at the O 1s and Ru 3d regions as well as the effects of puttingtering were investigated using the IMPACT facility at Purdue University.
Abstract: We investigated Ru mirror contamination and subsequent EUV reflectivity loss using the IMPACT facility at Purdue
University. Because Ru can either be used as a grazing mirror or as a capping layer for multilayer normal mirror, we
examined the angular dependency of XPS peak area intensity at the O 1s and Ru 3d regions as well as the effects of
sputtering. Although no change in intensity has been observed at lower take-off angles from the target surface, the peak
area intensity starts changing with increasing θ (i.e., emission observation angle, representing the angle between the
target surface plane and detector entrance). Among different components, the effect of water and oxidized carbon are
found to be most notable when viewed at lower θ, and primarily responsible for degrading the reflectivity of the Ru
layer. On the other hand, the effect of OH becomes dominant with increasing observation angle θ, and thus plays a key
role to suppress optical transmission. Moreover, atomic carbon effect is found to peak when observed at 30°, and most
likely plays an important role in degrading both reflectivity and transmission. This is also because of the total photon
path length in the Ru film at different angles. During the contamination process, the EUV reflectivity of the Ru film is
found to significantly degrade in the presence of additional secondary electrons from the focusing Ru mirror of the EUV
setup. This effect could be explained in the light of a competition between oxidation and carbonization processes on Ru
surface.
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Journal Article•
TL;DR: In this paper, the chemical influence of cleaning of the Ru capping layer on the extreme ultraviolet (EUV) reflector surface has been investigated and two main approaches for EUV reflector cleaning: wet chemical treatments (sulfuric acid and hydrogen peroxide mixture) and dry cleaning (oxygen plasma and UV/ozone treatment) were tested.
Abstract: Chemical Effect of Dry and Wet Cleaning of the Ru Protective Layer of the Extreme Ultraviolet (EUV) Lithography Reflector Leonid Belau 1 , Jeong Y. Park 2 , Ted Liang 3 , Hyungtak Seo 1 , and Gabor A. Somorjai 1,2,* Department of Chemistry, University of California, Berkeley, California 94720 Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA Components Research, Technology and Manufacturing Group, Intel Corporation, Santa Clara, CA 95054 Abstract We report the chemical influence of cleaning of the Ru capping layer on the extreme ultraviolet (EUV) reflector surface. The cleaning of EUV reflector to remove the contamination particles has two requirements; to prevent corrosion and etching of the reflector surface and to maintain the reflectivity functionality of the reflector after the corrosive cleaning processes. Two main approaches for EUV reflector cleaning: wet chemical treatments (sulfuric acid and hydrogen peroxide mixture (SPM), ozonated water, and ozonated hydrogen peroxide) and dry cleaning (oxygen plasma and UV/ozone treatment) were tested. The change of surface morphology and roughness were characterized using scanning electron microscopy (SEM) and atomic force microscopy (AFM), while the surface etching and change of oxidation states were probed with X-ray photoelectron spectroscopy (XPS). Significant surface oxidation of the Ru capping layer was observed after oxygen plasma and UV/ozone treatment, while the oxidation is unnoticeable after SPM treatment. Based on these surface studies, we found that SPM treatment exhibits the minimal corrosive interactions with Ru capping layer. We address
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References
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TL;DR: In this paper, the surface chemical state of two carbon nanotube materials and the evidence of surface modification from a reaction with dichlorocarbene were determined using X-ray photoelectron spectroscopy (XPS).
128 citations
TL;DR: In this article, the authors summarize the thermal and radiation-induced surface chemistry of bare Ru exposed to gases; the emphasis is on H2O vapor, a dominant background gas in vacuum processing chambers.
119 citations
TL;DR: In this paper, a comprehensive model of radiation-induced carbon contamination of extreme ultraviolet (EUV) optics is presented, which describes the key processes that contribute to the deposition of a carbon film on a multilayer optic when the optic is exposed to EUV radiation in the presence of residual hydrocarbons.
Abstract: A comprehensive model of radiation-induced carbon contamination of extreme ultraviolet (EUV) optics is presented. The mathematical model describes the key processes that contribute to the deposition of a carbon film on a multilayer optic when the optic is exposed to EUV radiation in the presence of residual hydrocarbons. These processes include the transport of residual hydrocarbons to the irradiated area, molecular diffusion across the optic surface, and the subsequent dissociation or “cracking” of the hydrocarbon by both direct EUV ionization and secondary electron excitation. Model predictions of carbon growth are compared to measurements taken on optics exposed to EUV in the presence of residual hydrocarbons. Model estimates of hydrocarbon film growth under various conditions of hydrocarbon partial pressures and EUV power demonstrate the sensitivity of film growth to varying operating conditions. Both the model and experimental data indicate that the predominant cause of hydrocarbon dissociation is bo...
117 citations
Book•
17 May 1983
TL;DR: Experimental Techniques Core Electron Spectra Valence Electron Spectrum Spectra Spectra From Solids and Surfaces Photo Ionization Cross Sections and Quantitative Analytical Applications Angular Distribution of Photoelectrons References and Notes Index as mentioned in this paper
Abstract: Experimental Techniques Core Electron Spectra Valence Electron Spectra Spectra From Solids and Surfaces Photo Ionization Cross Sections and Quantitative Analytical Applications Angular Distribution of Photoelectrons References and Notes Index
111 citations
TL;DR: In the case of a severe accident in a nuclear power plant, interactions of gaseous RuO 4 with reactor containment building surfaces (stainless steel and epoxy paint) could possibly lead to a black Ru-containing deposit on these surfaces as mentioned in this paper.
88 citations