The Reasearch Of Extreme Ultraviolet Spectrum And Time Characteristics From Xe Plasma Produced By7mm Diameter Capillary Discharge

Extreme Ultraviolet (EUV) Lithography uses the wavelength of13.5nm extremeultraviolet emission as exposure light, having become a popular one in the nextgeneration lithography, and EUV light is the key component of providing the13.5nmextreme ultraviolet emission output. In the capillary discharge mechanism, no one hasresearched on capillary discharge with capillary in diameter＞6mm. Capillary dischargewith large diameter not only could reduce ablation of the inner wall, but also couldimprove the collection efficiency of radiation light. In this paper,13.5nm extremeultraviolet emission is obtained, and the impact of Xe flow rate and the amplitude ofmain pulse current on Xe spectrum are researched, and the impact of prepulse dischargeto Xe radiation characteristic by contrast is analyzed, at last, the time characteristics of13.5nm emission is discussed.Discharge produced plasma EUV source system is introduced and its maincomponent and function is illustrated, while the plasma Z-pinch theory and snow plowmodel theory of capillary discharge are introduced. Time characteristics of plasma axialpinch is simulated, after that, the impact of electron temperature on percentage of Xedifferent valence state ions is researched.The influence of Xe flow rate and the amplitude of main pulse current on radiationintensity from Xe8+~Xe11+is discussed, and the impact of prepulse discharge on Xeradiation characteristic is analyzed. With the Xe flow rate increasing, the trend of the Xespectral line intensity from Xe8+~Xe11+is to increase first, then decrease, when the Xeflow rate is increased to a certain value, the spectral line intensity achieves the strongest.At the same time, there is a limited flow rate, respectively, when increasing to the limit,the corresponding ion spectral line disappears, the higher the number of Xe ions, thelower the limited flow rate. The experimental results also show that with the increasingof the amplitude of main pulse current, the spectral line intensity from Xe8+~Xe11+is tostrengthen. Prepulse discharge has no effect on the spectral line intensity from Xe, butthe gas breakdown stability is improved, the gas breakdown range is increased, and thebreakdown delay time is decreased.On the basis of13.5nm extreme ultraviolet emission spectrum obtained, the time characteristics of13.5nm radiation light is studied. Firstly, the impact of the amplitude ofmain pulse current on the time characteristics is researched, then the impact of Xe flowrate on the characteristics is researched. The experimental results show the larger theamplitude of main pulse current, the larger the area the radiation signal covered, that is tosay, the stronger the in-band13.5nm radiation intensity, while the two peaks of radiationsignal also enhances, and the time position of the first peak is to advance. However thelarger the Xe flow rate, the smaller the area the radiation signal covered, it means theweaker the in-band13.5nm radiation intensity, while the two peaks of radiation signalalso declines, and the time position of the first peak is to postpone. In theory, the Z-pinchprocess of plasma is simulated, according to the compression process, the timecharacteristics of13.5nm radiation light is analysed and discussed.