Study On EUV Source Of Z-pinch Xe Plasma Pumbed By Capillary Discharge

In order to get much smaller feature for the ICs, the technology of next generation lithography(NGL) has been put forward. Comparing with other technologies, the extreme ultraviolet(EUV) lithograph technology, which has better continuity in the optical lithography, is one of the most important technologies. According to the requirements, the EUV source has been developed along two ways. One way is to develop a high power and high repetition frequency source, which is used to satisfy the high volume manufacturing requirements. And the other way is to build a moderate power test source to detect the collectors, mask and photosensitive resist. The latter source requires more steady, moderate power, simple and cheap. And the EUV source of Z-pinch xenon plasma pumbed by capillary discharge, which has the advantages of simple structure, steady power, high collection efficiency and so on, is one of the key technology as the test source.For a capillary discharge Z-pinch Xe plasma EUV source, systemic researches about mechanism, better discharge structures and parameters are the key factors to achieve high power and better stability13.5nm(2%bandwidth) emission. In order to achieve high power and high stability13.5nm(2%bandwidth) emission, the theoretical researches, experimental equipment improvements, experimental researches, as well as the design and building of the1kHz EUV source have been studied in this paper.Theoretically, the energy level parameters of Xe ions have been calculated with the Cowan code. The abundances of different valences for Xe ions under different conditions have been calculated by the collision-radiation model as well. According to the upper results, the emission spectra under different conditions have been simulated in consideration of the broadening of spectral line. Moreover, the pinch processes of Xe plasma in the capillary under different discharge current and Xe pressure, have been simulated with the snow-plow model. And the multi-pinch process has been studied as well. In combination with the experimental results, the effect of the discharge current, Xe pressure and the inner diameter of capillary on the pinch processes have been analyzed. In addition, the influence of the nner diameter of capillary and plasma length on the collection efficiency and power at the intermediate focus have been calculated in consideration of the parameters of the collectors.The EUV source of Z-pinch xenon plasma pumbed by capillary discharge mainly consists of five parts: the power system, discharge system, gas system, vacuum system and detection system. The problems which existed in the source have been improved to satisfy the requirements for high power and high stability.The effective pinch of plasma and EUV radiation have been realized with the rebuilt structure. Experimentally, the effect of the pre-pulse on the EUV sepctra, the time and power stabilities have been studied systemically. Based on the experimental results, the pre discharge and main discharge were used in the latter experiments. In order to optimize the value of the main current, flow rate of Xe, inner diameter of the capillary, the assist gas and the length of the plasma, the effects of these parameters on the spectra and the plasma state of the EUV source have been studied scientifically. Moreover, The physical mechanism of the EUV source of Z-pinch xenon plasma pumbed by capillary discharge have been studied by detection the effects of these parameters on the temporal evolution of the13.5nm(2%bandwidth) emission. The results show that there are multi-peaks for the temporal evolution of the13.5nm(2%bandwidth) emission under high current and low Xe pressure. However, there are little researches and analysis about the phenomena. Moreover, it can be founded that the13.5nm(2%bandwidth) emission intensity can be increased by mixing Xe with He. The optimum mixing ratio has been got. By comparing the spectra and temporal evolution of the13.5nm(2%bandwidth) emission under different He: Xe mixing ratio and the Xe/Ne, Xe/Ar mixture, the physical mechanism that mixing Xe with He can increase13.5nm(2%bandwidth) emission intensity has been interpreted.According to the upper researches, an1kHz capillary discharge Z-pinch EUV source has been built, which includes the power system, the discharge system, the pumped gas system, the vacuum system, the detection system, the cooled system, the collectors and the debris mitigation tool. The performance for each component has been tested. The results show that all of them can basically meet the design index and experimental requirements. The13.5nm emission under monopulse and frequency condition, the optimum Xe flow rate and He: Xe ratio have been got with the integrated1kHz EUV source.