Atak Anıl Çağrı, Ünal Emre, Demir Hilmi Volkan
Department of Electrical and Electronics Engineering, Department of Physics, UNAM - National Nanotechnology Research Center and Institute of Materials Science and Nanotechnology, Bilkent University, Ankara, 06800, Turkey.
Luminous! Center of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore.
Microsyst Nanoeng. 2025 Mar 12;11(1):47. doi: 10.1038/s41378-025-00888-5.
Three-dimensional (3D) printing allows for the construction of complex structures. However, 3D-printing vertical structures with a high aspect ratio remains a pending challenge, especially when a high lateral resolution is required. Here, to address this challenge, we propose and demonstrate micro-3D sculptured metastructures with deep trenches of 1:4 (width:height) aspect ratio for sub-10 µm resolution. Our construction relies on two-photon polymerization for a 3D-pattern with its trenches, followed by electroplating of a thick metal film and its dry etching to remove the seed layer. To test the proposed fabrication process, we built up three-dimensional RF metastructures showcasing the depth effect as the third dimension. Using the numerical solutions, we custom-tailored these metastructure resonators to fall within a specific resonance frequency range of 4-6 GHz while undertaking comparative analyses regarding overall footprint, quality factor, and resonance frequency shift as a function of their cross-sectional aspect ratio. The proposed process flow is shown to miniaturize metal footprint and tune the resonance frequency of these thick 3D-metastructures while increasing their quality factor. These experimental findings indicate that this method of producing trenches via 3D-printing provides rich opportunities to implement high-aspect-ratio, complex structures.
三维（3D）打印能够构建复杂结构。然而，打印高纵横比的垂直结构仍然是一个悬而未决的挑战，尤其是在需要高横向分辨率的情况下。在此，为应对这一挑战，我们提出并展示了具有1:4（宽度：高度）纵横比深沟槽的微3D雕刻超材料结构，以实现亚10微米的分辨率。我们的构建过程依赖于双光子聚合来形成带有沟槽的3D图案，随后电镀厚金属膜并进行干法蚀刻以去除种子层。为测试所提出的制造工艺，我们构建了三维射频超材料结构，展示了作为第三维度的深度效应。利用数值解，我们定制这些超材料谐振器，使其落在4 - 6 GHz的特定谐振频率范围内，同时对其整体尺寸、品质因数和谐振频率随横截面纵横比的变化进行了对比分析。所提出的工艺流程被证明能够使金属尺寸最小化，并调节这些厚3D超材料结构的谐振频率，同时提高其品质因数。这些实验结果表明，这种通过3D打印制造沟槽的方法为实现高纵横比的复杂结构提供了丰富的机会。
