| Abstract
| - Carbonaceous deposits produced on Ru-capped multilayer mirrors under extreme ultraviolet (EUV) irradiationin the presence of adventitious gaseous hydrocarbons are a major obstacle to process implementation of EUVlithography, the key to fabrication of next generation semiconductor chips. The technical problem has beensimulated by examining graphitic film growth on Ru(0001) under low-energy electron irradiation in the presenceof 1-butene, C5−C8 linear alkanes, and toluene. We show that this provides a practical and reliable meansof simulating the photon-induced chemistry and of distinguishing between benign and harmful species. Linearalkanes up to n-heptane are relatively benign, whereas n-octane and toluene are much more harmful, givingrise to rapid growth of graphitic films of a thickness sufficient to seriously impair mirror reflectivity. 1-Buteneexhibits behavior in between these extremes. These properties may be understood in terms of the surfaceresidence lifetimes of the various adsorbates on graphitic surfaces.
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