Interaction of benzene with TiO2 surfaces: Relevance to contamination of extreme ultraviolet lithography mirror capping layers

摘要: The authors focus on thermal and nonthermal (radiation-induced) surface processes that affect the reflectivity of TiO2-capped multilayer mirrors used in extreme ultraviolet (EUV) lithography. Low energy electron beams mimic excitations initiated by EUV radiation. Where appropriate, comparison is made with bombardment vapor methyl methacrylate (C5H8O2). Benzene adsorbs desorbs reversibly TiO2, steady state coverage Θ found to be proportional logarithm benzene pressure p. This behavior described Tempkin adsorption isotherm, which has form Θ=const+logp. isotherm a consequence linear dependence Θ. In addition, measurements cross sections σ (cm2) for electron-stimulated dissociation clean C-covered TiO2 range 10–100eV reveal surprisingly large values (e.g., ∼3.5×10−17cm2 at 10eV primary energy). Thus, low secondary electrons excited lithography photons are e...