Mask substrate requirements and development for extreme ultraviolet lithography (EUVL)
Mask substrate requirements and development for extreme ultraviolet lithography (EUVL)
复制标题
极紫外光刻（EUVL）掩模基板的要求和发展
DOI：
10.1117/12.373338
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
M. Shell
中科院分区：
文献类型：
--
作者：
W. Tong;John S. Taylor;S. Hector;M. Shell
面罩被认为是EUVL需要大量研究和开发的领域之一。硅晶片将用于阿尔法级EUVL曝光工具的掩模基板，因为它们的低缺陷水平和高质量的表面光洁度。然而，硅具有大的热膨胀系数，这导致由于EUV光的吸收而导致不可接受的图像失真。可能需要低热膨胀玻璃或玻璃陶瓷，以满足70 nm节点及以上的误差预算。由于EUVL掩模用于反射，因此在图案化之前，它们被涂覆有多层。表面缺陷，如抛光痕迹、颗粒、划痕或凹陷，是多层涂层中缺陷的潜在成核位点，这可能导致印刷缺陷。因此，我们正在加速低热膨胀掩模基板的缺陷减少和表面精加工方面的开发，以了解控制可印刷缺陷的长期问题，并建立供应掩模的基础设施。在本文中，我们解释了EUVL掩模基板的技术要求，并描述了我们在建立EUVL掩模的SEMI标准方面所做的努力。我们亦将报告供应商为我们的开发活动生产低热膨胀掩模基板的早期进展。
The mask is deemed one of the areas that require significant research and development in EUVL. Silicon wafers will be used for mask substrates for an alpha-class EUVL exposure tool due to their low-defect levels and high quality surface finish. However, silicon has a large coefficient of thermal expansion that leads to unacceptable image distortion due to absorption of EUV light. A low thermal expansion glass or glass-ceramic is likely to be required in order to meet error budgets for the 70 nm node and beyond. Since EUVL masks are used in reflection, they are coated with multilayers prior to patterning. Surface imperfections, such as polishing marks, particles, scratches, or digs, are potential nucleation sites for defects in the multilayer coating, which could result in the printed defects. Therefore we are accelerating developments in the defect reduction and surface finishing of low thermal expansion mask substrates in order to understand long-term issues in controlling printable defects, and to establish the infrastructure for supplying masks. In this paper, we explain the technical requirements for EUVL mask substrates and describe our efforts in establishing a SEMI standard for EUVL masks. We will also report on the early progress of our suppliers in producing low thermal-expansion mask substrates for our development activities.