Next Generation Debris-Free EUV Source using Fast Z-pinch Discharge in Cylindrical Gas Curtain

为了开发高质量、高输出功率的新一代无碎片极紫外光源，本研究确定了以下目标：提高从电能储存到极紫外光发射的能量转换效率；抑制碎片的产生，2。开发一种不干扰排放气流的碎片屏蔽，以减轻上述方法无法清除的碎片。由于通常的z型夹紧放电头采用绝缘壁，因此壁材产生碎片。因此，为了防止碎片的产生，已经拆除了绝缘墙，并打算在径向上收集EUV。利用光谱仪，从杂质谱线的显著减少中证实了碎片产生的抑制。此外，发现特别设计的圆柱形气幕具有放电气体约束功能，这是一开始没有想到的。前一种器件的杂散电感很大，无法获得大的放电电流。然后，对电路设计进行重新检查。为了尽可能地减小放电回路末级的杂散电感，采用了LC反转发生器和两级磁脉冲压缩（MPC）电路。实验得到的电流幅值为22 kA，短路时脉宽为260 ns。此外，为了提高从电输入到极紫外光发射的转换效率，设计了一种利用射频放电产生等离子体射流的装置。按照原计划，采用射频预电离等离子体射流进行了z捏放试验。结果发现，使用射频预电离射流时，由于腔室充满弱电离等离子体，放电发生在等离子体射流以外的其他地方。因此，在这种情况下，不可能得到z夹缩等离子体。为了保持腔室内部的高真空，我们正在尝试改善腔室的真空状态，用涡轮分子泵来抽除腔室，而不是用它作为扩散器。少

To develop a next generation debris-free extreme ultraviolet (EUV) source with high quality and high output power, the objectives of this study were decided as follows: 1. increase energy conversion efficiency from electrical energy storage to EUV emission, 2. suppress the debris generation, 3. develop a debris shield, which does not interfere the discharge gas flow, to mitigate the debris that cannot be removed by the above mentioned method.Since the usual Z-pinch discharge head employs an insulating wall, debris is generated from the wall material. Therefore, in order to prevent the debris from generating, the insulating wall has been removed and the EUV has been intended to be collected in the radial direction. Using a spectrometer, suppression of debris generation was confirmed from the remarkable reduction of impurity lines. In addition, the specially designed cylindrical gas curtain was found to have a discharge gas confinement function, which was not supposed at first.The stray … More inductance of the former device was very large and it was impossible to get large discharge current. Then, the circuit design was re-examined. To reduce the stray inductance in the final stage of discharge circuit as much as possible, an LC inversion generator and a two-stage magnetic pulse compression (MPC) circuit have been adopted. Experimentally obtained current has the amplitude of 22 kA and the pulse width of 260 ns for short-circuit. Moreover, to increase the conversion efficiency from the electrical input to EUV emission, a device which generates a plasma jet by using RF discharge was set.According to the original plan, Z-pinch discharge was tried using the RF preionized plasma jet. As a result, it was found that in case of using RF preionized jet since the chamber was filled with weakly ionized plasma and discharge occurred at other place other than the plasma jet. Therefore, no Z-pinch plasma could be obtained in this case. To keep the inside of chamber high vacuum, using the turbo molecular pump to evacuate the chamber instead of using it for the diffuser, we are now trying to improve the vacuum state in the chamber. Less