Laboratory for Micro- and Nanotechnology, Paul Scherrer Institute, 5232 Villigen, Switzerland.
Nanoscale. 2015 Mar 7;7(9):4031-7. doi: 10.1039/c4nr07420c.
All nanofabrication methods come with an intrinsic resolution limit, set by their governing physical principles and instrumentation. In the case of extreme ultraviolet (EUV) lithography at 13.5 nm wavelength, this limit is set by light diffraction and is ≈3.5 nm. In the semiconductor industry, the feasibility of reaching this limit is not only a key factor for the current developments in lithography technologies, but also is an important factor in deciding whether photon-based lithography will be used for future high-volume manufacturing. Using EUV-interference lithography we show patterning with 7 nm resolution in making dense periodic line-space structures with 14 nm periodicity. Achieving such a cutting-edge resolution has been possible by integrating a high-quality synchrotron beam, precise nanofabrication of masks, very stable exposures instrumentation, and utilizing effective photoresists. We have carried out exposure on silicon- and hafnium-based photoresists and we demonstrated the extraordinary capability of the latter resist to be used as a hard mask for pattern transfer into Si. Our results confirm the capability of EUV lithography in the reproducible fabrication of dense patterns with single-digit resolution. Moreover, it shows the capability of interference lithography, using transmission gratings, in evaluating the resolution limits of photoresists.
所有的纳米制造方法都有一个内在的分辨率限制，这是由它们的控制物理原理和仪器决定的。在 13.5nm 波长的极紫外(EUV)光刻中，这个限制由光的衍射决定，约为 3.5nm。在半导体行业中，达到这个极限的可行性不仅是光刻技术当前发展的关键因素，也是决定光子光刻是否将用于未来大规模制造的一个重要因素。我们使用 EUV 干涉光刻技术展示了在具有 14nm 周期性的密集线-空间结构中以 7nm 分辨率进行图案化的能力。通过集成高质量的同步加速器光束、掩模的精确纳米制造、非常稳定的曝光仪器以及利用有效的光致抗蚀剂，实现了如此前沿的分辨率。我们已经在硅和铪基光致抗蚀剂上进行了曝光，并证明了后者作为硬掩模在将图案转移到 Si 中的非凡能力。我们的结果证实了 EUV 光刻在可重复制造具有个位数分辨率的密集图案方面的能力。此外，它还展示了使用透射光栅的干涉光刻在评估光致抗蚀剂分辨率限制方面的能力。
