Robust and reliable actinic ptychographic imaging of highly periodic structures in EUV photomasks
Robust and reliable actinic ptychographic imaging of highly periodic structures in EUV photomasks
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EUV 光掩模中高周期结构的稳健且可靠的光化叠层成像
DOI：
10.1117/12.2641726
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
H. Kapteyn
中科院分区：
文献类型：
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作者：
Bin Wang;Nathan J Brooks;M. Tanksalvala;Yuka Esashi;Nicolas Jenkins;Peter C Johnsen;I. Binnie;Guan Gui;Yunzhe Shao;M. Murnane;H. Kapteyn
随着EUV光刻过渡到大批量制造，13.5 nm波长的光化检测工具对于理解EUV掩模缺陷的可印刷性以及对于长期使用中出现的可能缺陷的工厂内监测是有吸引力的。相干衍射成像（CDI）是一种无透镜成像技术，其允许在EUV中进行相位和振幅、无像差、高分辨率成像。此外，基于超快激光器的高次谐波产生（HHG）的光源是CDI的经证明可行的相干光源，其通量足以进行快速大面积检查和小面积成像。通过结合CDI和HHG，我们实现了光化EUV光掩模检测的低成本桌面规模的设置。此外，我们提出并证明了一个解决方案，通过仔细的照明工程周期性结构的重叠关联成像的挑战。
As EUV lithography transitions to high volume manufacturing, actinic inspection tools at 13.5 nm wavelength are attractive for understanding the printability of EUV mask defects, as well as for in-fab monitoring for possible defects emerging from extended use. Coherent diffractive imaging (CDI) is a lensless imaging technique that allows for phaseand-amplitude, aberration-free, high-resolution imaging in the EUV. Moreover, sources based on high harmonic generation (HHG) of ultrafast lasers are a proven viable coherent light source for CDI, with flux sufficient for rapid large-area inspection and small-area imaging. By combining CDI and HHG, we implemented actinic EUV photomask inspection on a low-cost tabletop-scale setup. Moreover, we propose and demonstrate a solution to the challenge of ptychographic imaging of periodic structures through careful illumination engineering.