摘要
Extreme ultraviolet lithography is most promising for the next generation lithography. However, debris from laser-produced plasma, particularly energetic ions, severely decreases the lifetime of extreme ultraviolet optics. We measured the characteris- tics of ions from tin plasma by the time of flight method with a frequency-doubled Nd： YAG laser at the intensity of 3.5x1010 W/cm2 （532 nm, 8 ns）. Our measurement shows that the maximum and peak of tin ions energies from plasma under the above experimental parameters are about 4.2 and 1.8 keV, respectively. Moreover, it is found that kinetic energy angular distribution of tin ions can be fitted by cos0.8（θ）, where θ is the angle with respect to the target normal. We also investigated the mitigation effect of argon, helium gases to the tin ions, and found that tin ions from the plasma can be mitigated effectively at the pressure -38 mTorr for argon or -375 mTorr for helium, respectively.
极端紫外平版印刷术为下一代平版印刷术是很有希望的。然而，从生产激光的血浆的碎片，特别地精力充沛的离子，严重地减少极端紫外光学的一生。我们从听血浆测量了离子的特征等到有加倍频率的 Nd 的飞行方法：在 3.5O
基金
supported by the National Natural Science Foundation ofChina (Grant Nos. 60978014,61178022 and 11074027)
the Basic Research Fund from Sci. & Tech. Department of Jilin Province (Grant Nos.20100521,20100168 and 20111812)
