Multilayer reflective coatings for extreme-ultraviolet lithography
Multilayer reflective coatings for extreme-ultraviolet lithography
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用于极紫外光刻的多层反射涂层
DOI：
10.1117/12.309600
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
J. Folta
中科院分区：
文献类型：
--
作者：
C. Montcalm;S. Bajt;P. Mirkarimi;E. Spiller;F. J. Weber;J. Folta
反射极紫外（EUV）辐射的多层镜涂层是EUV光刻的关键使能技术。在13.4 nm处的反射率为67.5%的SO/Si多层膜现在常规地实现，并且在11.4 nm处的反射率为70.2%的Mo/Be多层膜获得。高反射率是通过仔细控制衬底质量、层厚度、多层材料、界面质量和表面终止来实现的。反射率和膜应力被认为是稳定的相对于应用于EUV光刻的要求。反射率峰值位置的运行到运行的再现性被表征为优于0.2%，从而在本光刻系统设计中使用的七个多层涂覆的反射镜之间提供所需的波长匹配。涂层的均匀性得到改善，在150 mm直径的基板上优于0.5%。EUV多层反射镜技术的这些改进将使我们能够满足下一代EUV光刻系统的大型光学基板涂层的严格规格。
Multilayer mirror coatings which reflect extreme UV (EUV) radiation are a key enabling technology for EUV lithography. So/Si multilayers with reflectances of 67.5 percent at 13.4 nm are now routinely achieved and reflectances of 70.2 percent at 11.4 nm were obtained with Mo/Be multilayers. High reflectance is achieved with careful control of substrate quality, layer thicknesses, multilayer materials, interface quality, and surface termination. Reflectance and film stress were found to be stable relative to the requirements for application to EUV lithography. The run-to- run reproducibility of the reflectance peak position was characterized to be better than 0.2 percent, providing the required wavelength matching among the seven multilayer- coated mirrors used in the present lithography system design. Uniformity of coating was improved to better than 0.5 percent across 150 mm diameter substrates. These improvements in EUV multilayer mirror technology will enable us to meet the stringent specifications for coating the large optical substrates for our next-generation EUV lithography system.