Ji Jiaxin, Xu Pengfei, Lin Zhongwen, Chen Jiying, Li Jing, Meng Yonggang
College of Mechanical and Electronic Engineering, China University of Petroleum, QingDao 266580, China.
School of Mechanical Engineering, Dalian University of Technology, Dalian 116024, China.
Nanomaterials (Basel). 2020 May 13;10(5):937. doi: 10.3390/nano10050937.
The near-field photolithography system has attracted increasing attention in the micro- and nano-manufacturing field, due to the high efficiency, high resolution, and the low cost of the scheme. Nevertheless, the low quality of the nano-patterns significantly limits the industrial application of this technology. Theoretical calculations showed that the reason for the poor nano-patterns is the sharp attenuation of the surface plasmon polaritons (SPPs) in the photoresist layer. The calculation results suggest that the waveguide mode, which is composed of the chromium-equivalent dielectric layer-aluminum, can facilitate the energy flux density distribution in the photoresist layer, resulting in the enhancement of the field intensity of SPPs in the photoresist layer. This reduces the linewidth of nano-patterns, while it enhances the pattern steepness. Eventually, the focusing energy of the photoresist layer can be improved. The finite-difference time-domain method was employed to simulate and verify the theoretical results. It is found that for the rotational near-field photolithography with 355 nm laser illumination, the linewidths of the nano-patterns with and without the aluminum reflector are 17.54 nm and 65.51 nm, respectively. The robustness of the experimental results implies that the application of the aluminum reflector enhances the focusing effect in the photoresist, which can broaden the application of the near-field photolithography.
近场光刻系统因其方案的高效率、高分辨率和低成本，在微纳制造领域受到越来越多的关注。然而，纳米图案的低质量严重限制了该技术的工业应用。理论计算表明，纳米图案质量差的原因是光刻胶层中表面等离激元极化激元（SPPs）的急剧衰减。计算结果表明，由等效铬介电层-铝组成的波导模式可以促进光刻胶层中的能流密度分布，从而增强光刻胶层中SPPs的场强。这减小了纳米图案的线宽，同时提高了图案的陡度。最终，可以提高光刻胶层的聚焦能量。采用时域有限差分法对理论结果进行了模拟和验证。结果发现，对于355nm激光照明的旋转近场光刻，有无铝反射器时纳米图案的线宽分别为17.54nm和65.51nm。实验结果的稳健性表明，铝反射器的应用增强了光刻胶中的聚焦效果，这可以拓宽近场光刻的应用范围。
