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

为了研制新一代高质量、高输出功率的无碎片极紫外光源，本论文的研究目标如下：1。增加从电能存储到EUV发射的能量转换效率，2.抑制碎片产生，3.开发不干扰放电气流的碎片屏蔽，以减轻不能通过上述方法去除的碎片。由于通常的Z箍缩放电头采用绝缘壁，因此碎片从壁材料产生。因此，为了防止产生碎片，绝缘壁已经被移除，并且EUV已经被意图在径向方向上收集。使用光谱仪，抑制碎片的产生证实了显着减少杂质线。此外，特别设计的圆柱形气幕被发现具有放电气体限制功能，这在一开始是不应该的。 关于我们 前一种装置的电感很大，不可能获得大的放电电流。然后，重新检查电路设计。为了尽可能减小放电回路末级的杂散电感，采用了LC逆变发生器和两级磁脉冲压缩（MPC）回路。实验测得的短路电流幅值为22 kA，脉宽为260 ns。此外，为了提高从电输入到极紫外发射的转换效率，设置了一个利用射频放电产生等离子体射流的装置，并按照原计划，利用射频预电离等离子体射流进行了Z箍缩放电的尝试。结果发现，在使用RF预电离射流的情况下，由于腔室填充有弱电离等离子体，并且放电发生在等离子体射流之外的其它地方。因此，在这种情况下不能获得Z箍缩等离子体。为了保持真空室内部的高真空，我们正在尝试用涡轮分子泵对真空室进行抽真空，而不是用它作为扩散器，以改善真空室的真空状态。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