Effect of Plasma Density on Discharge Produced Plasma Extreme Ultraviolet Source

Condition of the plasma is one of the key factors affecting the power and the conversion efficiency of the expreme ultraviolet(EUV) source. The effects of the Xe flow rate on spectra and plasma for discharge produced plasma extreme ultraviolet source were investigated theoretically and experimentally, which was important to optimize the running condition of the EUV source. Moreover, the relationship between the distributions of abundances of ions and electron temperature as well as the density under non-local thermodynamic equilibrium were simulated with the Collisional-Radiation model. The variation tendency of the intensity for Xe8+similar to Xe11+ 4d-5p transitions on electron temperature was derived. The spectra detected by the rowland spectrometer was detected and analyzed under different density of the plasma with the capillary discharge produced plasma technology. Meanwhile, the effect of Xe gas flow rate on the condition of the plasma was studied as well. The experiments and theory showed that, during the Z-pinch process, the temperature decreased when the flow rate of Xe was increasing. And the average electron temperature was approximated to 29 eV when the current was 28 kA and the flow rate of Xe was 0.4 sccm. Meanwhile, the optimal flow rate for 13.5 nm(2%bandwidth) emission, mainly due to 4d-5p transition of Xe10+ ions, was among 0.3 similar to 0.4 sccm.