Liu Tao, Tong Xujie, Tian Shuoqiu, Xie Yuying, Zhu Mingsai, Feng Bo, Pan Xiaohang, Zheng Rui, Wu Shan, Zhao Ding, Chen Yifang, Lu Bingrui, Qiu Min
Nanolithography and Application Research Group, State Key Laboratory of ASIC and System, School of Information Science and Technology, Fudan University, Shanghai 200433, China.
Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China.
Nanoscale. 2022 Jun 30;14(25):9045-9052. doi: 10.1039/d2nr00594h.
Due to the perfection of the nanofabrication in nanotechnology and nanoscience, ice lithography (IL) by patterning ice thin-films with a focused electron beam, as a significant derivative technology of electron beam lithography (EBL), is attracting growing attention, evoked by its advantages over traditional EBL with respects of -fabrication, high efficiency, high accuracy, limited proximity effect, three-dimensional (3D) profiling capability, . However, theoretical modeling of ice lithography for replicated profiles on the ice resist (amorphous solid water, ASW) has rarely been reported so far. As the result, the development of ice lithography still stays at the experimental stage. The shortage of modeling methods limits our insight into the ice lithography capability, as well as theoretical anticipations for future developments of this emerging technique. In this work, an e-beam induced etching ice model based on the Monte Carlo algorithm for point/line spread functions is established to calculate the replicated profiles of the resist by ice lithography. To testify the fidelity of the modeling method, systematic simulations of the ice lithography property under the processing parameters of the resist thickness, electron accelerating voltage and actual patterns are performed. Theoretical comparisons between the IL on ASW and the conventional EBL on polymethyl methacrylate (PMMA) show superior properties of IL over EBL in terms of the minimum feature size, the highest aspect ratio, 3D nanostructure/devices, . The success in developing a modeling method for ice lithography, as reported in this paper, offers a powerful tool in characterizing ice lithography up to the theoretical level and down to molecular scales.
由于纳米技术和纳米科学中纳米制造技术的完善，通过聚焦电子束对冰薄膜进行图案化的冰光刻（IL）作为电子束光刻（EBL）的一项重要衍生技术，因其在制造、高效率、高精度、有限邻近效应、三维（3D）轮廓绘制能力等方面优于传统EBL而受到越来越多的关注。然而，到目前为止，关于冰光刻在抗蚀剂（非晶态固体水，ASW）上复制轮廓的理论建模鲜有报道。因此，冰光刻的发展仍停留在实验阶段。建模方法的不足限制了我们对冰光刻能力的深入了解，以及对这一新兴技术未来发展的理论预期。在这项工作中，基于蒙特卡罗算法建立了用于点/线扩展函数的电子束诱导蚀刻冰模型，以计算冰光刻抗蚀剂的复制轮廓。为了验证建模方法的保真度，在抗蚀剂厚度、电子加速电压和实际图案等加工参数下，对冰光刻特性进行了系统模拟。在ASW上的IL与在聚甲基丙烯酸甲酯（PMMA）上的传统EBL之间的理论比较表明，在最小特征尺寸、最高纵横比、3D纳米结构/器件等方面，IL优于EBL。本文报道的冰光刻建模方法的成功开发，为从理论层面到分子尺度表征冰光刻提供了一个强大的工具。
