Tuning extreme ultraviolet emission for optimum coupling with multilayer mirrors for future lithography through control of ionic charge states
Tuning extreme ultraviolet emission for optimum coupling with multilayer mirrors for future lithography through control of ionic charge states
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DOI：
10.1063/1.4862441
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发表时间：
2014-01
影响因子：
3.2
通讯作者：
H. Ohashi;T. Higashiguchi;Bowen Li;Yuhei Suzuki;M. Kawasaki;Tatsuhiko Kanehara;Y. Aida;S. Torii;T. Makimura;Weihua Jiang;P. Dunne;G. O’Sullivan;N. Nakamura
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文献类型：
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作者：
H. Ohashi;T. Higashiguchi;Bowen Li;Yuhei Suzuki;M. Kawasaki;Tatsuhiko Kanehara;Y. Aida;S. Torii;T. Makimura;Weihua Jiang;P. Dunne;G. O’Sullivan;N. Nakamura
我们报告的识别的最佳等离子体条件的激光产生的等离子体源的有效耦合与多层镜在6.x nm的超极紫外光刻。随着激光功率密度的增加，Nd：YAG激光产生的钆等离子体的峰值发射向低能量方向移动。在电子束离子阱（EBIT）研究中观察到电荷定义的发射光谱，并使用灵活的原子代码（FAC）确定负责的电荷状态。EBIT光谱显示出随着离子电荷的增加，在6.x nm处的强发射的峰值波长向更长波长的更大的系统移位。光谱的这种组合使关键离子阶段被确认为Gd 18+，在一系列的激光功率密度，与贡献的Gd 17+和Gd 19+负责的激光等离子体光谱中的较长波长的轻微移位。FAC计算还确定了观察到的带外发射和电荷的起源。
We report on the identification of the optimum plasma conditions for a laser-produced plasma source for efficient coupling with multilayer mirrors at 6.x nm for beyond extreme ultraviolet lithography. A small shift to lower energies of the peak emission for Nd:YAG laser-produced gadolinium plasmas was observed with increasing laser power density. Charge-defined emission spectra were observed in electron beam ion trap (EBIT) studies and the charge states responsible identified by use of the flexible atomic code (FAC). The EBIT spectra displayed a larger systematic shift of the peak wavelength of intense emission at 6.x nm to longer wavelengths with increasing ionic charge. This combination of spectra enabled the key ion stage to be confirmed as Gd18+, over a range of laser power densities, with contributions from Gd17+ and Gd19+ responsible for the slight shift to longer wavelengths in the laser-plasma spectra. The FAC calculation also identified the origin of observed out-of-band emission and the charge s...