Gunjala Gautam, Wojdyla Antoine, Sherwin Stuart, Shanker Aamod, Benk Markus P, Goldberg Kenneth A, Naulleau Patrick P, Waller Laura
Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, Berkeley, CA, 94720, USA.
Advanced Light Source, Lawrence Berkeley National Lab, Berkeley, CA, 94720, USA.
Sci Rep. 2020 Jul 15;10(1):11673. doi: 10.1038/s41598-020-68588-w.
We demonstrate a method for characterizing the field-dependent aberrations of a full-field synchrotron-based extreme ultraviolet microscope. The statistical uniformity of the inherent, atomic-scale roughness of readily-available photomask blanks enables a self-calibrating computational procedure using images acquired under standard operation. We characterize the aberrations across a 30-um field-of-view, demonstrating a minimum aberration magnitude of smaller than [Formula: see text] averaged over the center 5-um area, with a measurement accuracy better than [Formula: see text]. The measured field variation of aberrations is consistent with system geometry and agrees with prior characterizations of the same system. In certain cases, it may be possible to additionally recover the illumination wavefront from the same images. Our method is general and is easily applied to coherent imaging systems with steerable illumination without requiring invasive hardware or custom test objects; hence, it provides substantial benefits when characterizing microscopes and high-resolution imaging systems in situ.
我们展示了一种用于表征基于全场同步加速器的极紫外显微镜的场依赖像差的方法。市售光掩膜坯料固有的原子尺度粗糙度的统计均匀性，使得能够使用在标准操作下采集的图像进行自校准计算程序。我们在30微米的视场内表征像差，结果表明在中心5微米区域上平均的最小像差幅度小于[公式：见正文]，测量精度优于[公式：见正文]。所测量的像差场变化与系统几何结构一致，并且与同一系统的先前表征结果相符。在某些情况下，还可能从相同图像中额外恢复照明波前。我们的方法具有通用性，可轻松应用于具有可控照明的相干成像系统，无需侵入性硬件或定制测试物体；因此，在原位表征显微镜和高分辨率成像系统时，它具有显著优势。
