Research Institute of Advanced Materials (RIAM), Department of Materials Science and Engineering, Seoul National University, Daehak-Dong, Gwanak-Gu, Seoul 151-744, South Korea.
Nanoscale. 2017 Oct 5;9(38):14335-14346. doi: 10.1039/c7nr02666h.
Many high-resolution patterning techniques have been developed to realize nano- and microscale applications of electric devices, sensors, and transistors. However, conventional patterning methods based on photo or e-beam lithography are not employed to fabricate optical elements of high aspect ratio and a sub-100 nm scale due to the limit of resolution, high costs and low throughput. In this study, covalent bonding-assisted nanotransfer lithography (CBNL) was proposed to fabricate various structures of high resolution and high aspect ratio at low cost by a robust and fast chemical reaction. The proposed process is based on the formation of covalent bonds between silicon of adhesive layers on a substrate and oxygen of the deposited material on the polymer stamp. The covalent bond is strong enough to detach multiple layers from the stamp for a large area without defects. The obtained nanostructures can be used for direct application or as a hard mask for etching. Two nano-optical applications were demonstrated in this study, i.e., a meta-surface and a wire-grid polarizer. A perfect absorption meta-surface was generated by transferring subwavelength hole arrays onto a substrate without any post-processing procedures. In addition, a wire-grid polarizer with high aspect ratio (1 : 3) and 50 nm line width was prepared by the nano-transfer of materials, which were used as a hard mask for etching. Therefore, CBNL provides a means of achieving large-area nano-optical elements with a simple roll-to-plate process at low cost.
许多高分辨率图案化技术已经被开发出来，以实现电子设备、传感器和晶体管的纳米和微尺度应用。然而，由于分辨率、高成本和低产量的限制，传统的基于光或电子束光刻的图案化方法不用于制造高纵横比和亚 100nm 尺度的光学元件。在本研究中，提出了共价键辅助纳米转移光刻（CBNL），通过稳健且快速的化学反应以低成本制造具有高分辨率和高纵横比的各种结构。该方法基于在基底的粘附层的硅和聚合物印章上沉积材料的氧之间形成共价键。该共价键足够强，可以在没有缺陷的情况下从印章上分离出多层结构。所获得的纳米结构可以直接用于应用或作为蚀刻的硬掩模。本研究中展示了两个纳米光学应用，即超表面和线栅偏光器。通过将亚波长孔阵列转移到基底上，无需任何后处理步骤，生成了完美吸收的超表面。此外，通过纳米转移材料制备了高纵横比（1:3）和 50nm 线宽的线栅偏光器，该材料被用作蚀刻的硬掩模。因此，CBNL 提供了一种在低成本下通过简单的卷对板工艺实现大面积纳米光学元件的方法。
