Microsphere photolithography using reusable microsphere array mask for low-cost infrared metasurface fabrication
Microsphere photolithography using reusable microsphere array mask for low-cost infrared metasurface fabrication
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DOI：
10.1116/6.0002557
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发表时间：
2023-05
期刊：
影响因子：
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通讯作者：
C. Zhu;E. Kinzel
中科院分区：
文献类型：
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作者：
C. Zhu;E. Kinzel
微球光刻（MPL）是用于大规模制造周期性结构（诸如超颖表面）的替代低成本技术。该技术利用了光致抗蚀剂（PR）中产生的光子纳米射流，通过接近的微球，其暴露于准直紫外（UV）泛光照明。在基本方法中，微球阵列在曝光之前自组装在基底上或转移到基底上。暴露后，微球在显影步骤中被洗掉。回收和清洁这些微球以重新使用的过程是复杂的。本文研究了使用可重复使用的微球掩模，通过将微球固定在紫外线透明的支持。然后使其与具有受控压力的光致抗蚀剂接触。在所制造的样品的质量和由接触压力确定的掩模的磨损之间存在折衷。该系统使用基于数字微镜器件（DMD）的直写曝光系统来制作红外（IR）超颖表面。对这些元表面进行表征并与仿真模型进行比较。最后，使用单个可重复使用的掩模制造了一系列的50个分层图案化的IR元表面。当用热成像仪观察时，这些样品具有<3%的变异系数。这项工作显示了基于掩模的MPL和其他基于接触微透镜阵列的光刻技术用于低成本大规模制造的潜力。
Microsphere photolithography (MPL) is an alternative low-cost technique for the large-scale fabrication of periodic structures, such as metasurfaces. This technique utilizes the photonic nanojet generated in the photoresist (PR), by microspheres in near proximity, which are exposed to collimated ultraviolet (UV) flood illumination. In the basic approach, a microsphere array is self-assembled on, or transferred to, the substrate prior to exposure. After exposure, the microspheres are washed away in the development step. The process to recover and clean these microspheres for reuse is complicated. This paper investigates the use of reusable microsphere masks created by fixing the microspheres on a UV transparent support. This is then brought into contact with the photoresist with controlled pressure. There is a trade-off between the quality of the fabricated samples and the wear of the mask determined by the contact pressure. The system is demonstrated using a digital micromirror device (DMD)-based direct-write exposure system to fabricate infrared (IR) metasurfaces. These metasurfaces are characterized and compared to simulation models. Finally, a series of 50 hierarchically patterned IR metasurfaces was fabricated using a single reusable mask. These samples had a <3% coefficient of variance when viewed with a thermal camera. This work shows the potential of mask-based MPL and other contact microlens array-based photolithography techniques for low-cost large-scale fabrication.