Characterization of ion emission of an extreme ultraviolet generating discharge produced Sn plasma

Abstract

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.

Laser triggered Z-pinch broadband extreme ultraviolet source for metrology

“…The tin spectra provide a useful benchmark for the EUV performance of the galinstan plasmas, under the same range of conditions. The tin spectra show the expected UTA in the range of 13-15 nm as has been reported for both discharge [3][4][5]11 and LPP 12,13 sources. For galinstan, the tin UTA is also observed, but transitions in the range of 11.5-13 nm, due to gallium, and 14-18 nm, due to both gallium and indium, are also present.…”

“…3 EUV emission from a Z-pinch in a laser-triggered discharge between rotating electrodes coated with liquid tin has been studied previously. 4,5 The liquid metal coating overcomes the problem of electrode erosion, but it is necessary to maintain the tin above its melting temperature of 232 C. The EUV emission spectrum of pure tin plasma, at the appropriate conditions, is relatively narrow-band, with $50% of emission in the 13-15 nm range. For EUV metrology, the source parameters of interest are spectral radiance, wavelength range, and emission uniformity, as well as cost and ease of operation.…”

Gated pinhole camera imaging of the high-energy ions emitted by a discharge produced Sn plasma for extreme ultraviolet generation

“…The presence of these Sn ions among the debris was experimentally shown with an ion spectrometer. 8 The MCP images showed that these ions originate from a region close to the cathode surface, from the middle of the discharge gap, as well as from a region close to the anode surface.…”

“…[6][7][8] It was shown that suprathermal Sn ions with kinetic energies up to 100 keV are emitted by the plasma. The presence of ions with a higher velocity is also detected, but the nature of these ions was not identified.…”

Lifetime Calculations on Collector Optics from Laser Plasma Extreme Ultraviolet Sources with Minimum Mass

“…One of the critical issues in the development of a laser produced plasma extreme ultraviolet (LPP-EUV) source is achieving a high conversion efficiency and meanwhile, prolonging the lifetime of collector optics. [1] A major factor that determines the lifetime is ion sputtering of the material at the collector surface. [2] Experimentally, Srivastava et al [3] studied the lifetime of EUV mirror using measured Xe and Sn ion fluxes emitted from a z-pinch source.…”