毛细管放电氩等离子体的电离价研究

Study on Ionized Degree of Ar Plasma in Capillary Discharge

摘要: 毛细管放电软X射线激光或极紫外光刻光源研究中等离子体的电离价是一个重要的参量，它决定光源的波长。依据毛细管放电的特点以及参考文献中提供的数据推导出毛细管放电氩等离子体电离价的经验公式。利用国内首台毛细管放电极紫外光刻光源演示装置研究了氩等离子体的光谱，实验表明峰值~28 kA的脉冲电流对30 Pa氩气放电或峰值~34 kA的脉冲电流对40 Pa氩气放电都产生了Ar7+。而公式计算出30 Pa和40 Pa时分别需要24.4~39 kA和32.7~52.3 kA的峰值电流。这说明经验公式具有一定的实用意义。

Abstract: Ionized degree of Ar plasma in capillary discharge soft X-ray laser or Extreme Ultraviolet Lithographic (EUVL) source research was an important parameter which determined the wavelength of the plasma source. According to the characteristics of capillary discharge and the data from literature, we deduced an experiential expression of ion-ized degree of Ar plasma in capillary discharge by analogy method. With the first set of capillary discharge EUVL source demonstrative device in China, the spectra of Ar plasma was studied. It was found from experiment that either 30 Pa Ar gas discharged by peak pulse current of -28 kA or 40 Pa Ar gas discharged by peak pulse current of -34 kA could produce Ar7+ ion. While the simulating results showed that it was necessary for the 30 Pa and 40 Pa Ar gas to be ionized to Ar7+ ion by peak pulse current of 24.4 - 39 kA and 32.7 - 52.3 kA respectively. These results proved that the experien- tial expression had some definite practical significance.