Characterization of the PTB EUV reflectometry facility for large EUVL optical components
Characterization of the PTB EUV reflectometry facility for large EUVL optical components
复制标题
用于大型 EUVL 光学元件的 PTB EUV 反射测量设备的表征
DOI：
10.1117/12.482668
复制
发表时间：
2003
期刊：
影响因子：
--
通讯作者：
G. Ulm
中科院分区：
文献类型：
--
作者：
J. Tummler;H. Blume;G. Brandt;J. Eden;B. Meyer;Hartmut Scherr;F. Scholz;F. Scholze;G. Ulm
EUV光刻技术的发展关键取决于是否有合适的测量设备。为了满足行业要求，德国物理技术协会（PTB）最近在电子存储环BESSY II上安装了一个新的EUV反射计。这种新型反射计是为全尺寸EUVL光学器件的波长测量而设计的。样品的最大重量为50公斤，直径可达550毫米。除了波长和角度扫描外，还可以测量整个样品表面的双向散射。凹凸形状的表面是允许的。不仅一个反射镜的投影光学，而且多达五个掩模可以同时安装。对于未来的光刻生产工具，对光学和掩模的要求非常严格。多层反射率跨表面的均匀性和峰值反射的波长匹配性比现在更强。为了满足日益增长的对样本量和测量精度的要求，进一步优化了光束线的操作。漫射散射光限制了峰值反射率的不确定性。总相对不确定度为0.14%，重现性为0.07%。中心波长的不确定度主要由Kr 3d5/2-5p共振参考波长的不确定度给出。减少所有其他不确定度源后，中心波长的总不确定度为0.014%，重现性为0.008%。我们详细描述了EUV反射计，并讨论了不同不确定源下的最佳光束线条件。最近的测量结果说明了这些结果。
The development of EUV lithography is critically based on the availability of suitable metrology equipment. To meet the industries requirements the Physikalisch-Technische Bundesanstalt (PTB) recently has installed a new EUV reflectometer at the electron storage ring BESSY II. The new reflectometer is designed for at-wavelength metrology of full-size EUVL optics. Samples with a maximum weight of 50 kg and a diameter of up to 550 mm can be investigated. Besides wavelength and angle scans also the measurement of bi-directional scattering is possible within the full sample surface. Convex and concave shaped surfaces are allowed. Not only a single mirror of the projection optics but also up to five masks can be mounted simultaneously. For future lithography production tools the requirements for the optics and masks are very stringent. The homogeneity of the multilayer reflectivity across the surface and the wavelength matching of the peak reflection become even stronger than today. To meet the increasing demands not only regarding the sample size but also regarding the accuracy of the measurements the operation of the beamline was further optimized. Diffuse scattered light limits the uncertainty in the peak reflectance. A total relative uncertainty of 0.14% is achieved with a reproducibility of 0.07%. The uncertainty in the center wavelength is mainly given by the uncertainty for the reference wavelength of the Kr 3d5/2-5p resonance. The reduction of all other sources of uncertainty results in a total uncertainty of 0.014% in the center wavelength with a reproducibility of 0.008%. We present a detailed description of the EUV reflectometer and discuss the optimized beamline conditions with the different sources of uncertainties. The results are illustrated by recent measurements.