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The ion emission of a Sn-based discharge produced extreme ultraviolet producing plasma is characterized with the combined use of different time-of-flight techniques. An electrostatic ion spectrometer is employed to measure the average charge distribution of the emitted Sn ions. A dedicated Faraday cup configuration is used to measure the total ion flux from the source for different discharge energies. High-energy Sn ions emitted by the plasma with energies up to 100 keV have been identified. The number of high-energy ions increases for higher electrical input energy into the plasma while the signal associated with the expanding plasma ions does not show such dependence. The ion energy distribution for a bulk of detected ions is calculated based on the Faraday cup measurements and compared with theoretical plasma expansion dynamics. [ABSTRACT FROM AUTHOR]

Future generation lithography tools will use extreme ultraviolet radiation to enable the printing of sub-50 nanometer features on silicon wafers. The extreme ultraviolet radiation, coming from a pulsed discharge, photoionizes the low pressure background gas in the tool. A weakly ionized plasma is formed, which will be in contact with the optical components of the lithography device. In the plasma sheath region ions will be accelerated towards the surfaces of multilayer mirrors. A self-consistent kinetic particle-in-cell model has been applied to describe a radiation driven plasma. The simulations predict the plasma parameters and notably the energy at which ions impact on the plasma boundaries. We have studied the influence of photoelectron emission from the mirror on the sheath dynamics and on the ion impact energy. Furthermore, the ion impact energy distribution has been convoluted with the formula of Yamamura and Tawara [At. Data Nucl. Data Tables 62, 149 (1996)] for the sputter yield to obtain the rate of physical sputtering. The model predicts that the sputter rate is dominated by the presence of doubly ionized argon ions. [ABSTRACT FROM AUTHOR]

We use Raman spectroscopy to show that exposing few-layer graphene to extreme ultraviolet (EUV, 13.5 nm) radiation, i.e., relatively low photon energy, results in an increasing density of defects. Furthermore, exposure to EUV radiation in a H2 background increases the graphene dosage sensitivity, due to reactions caused by the EUV induced hydrogen plasma. X-ray photoelectron spectroscopy results show that the sp2 bonded carbon fraction decreases while the sp3 bonded carbon and oxide fraction increases with exposure dose. Our experimental results confirm that even in reducing environment oxidation is still one of the main source of inducing defects. [ABSTRACT FROM AUTHOR]