Gan Zhuofei, Feng Hongtao, Chen Liyang, Min Siyi, Liang Chuwei, Xu Menghong, Jiang Zijie, Sun Zhao, Sun Chuying, Cui Dehu, Li Wen-Di
Department of Mechanical Engineering, University of Hong Kong, Hong Kong, China.
School of Microelectronics, Southern University of Science and Technology, Shenzhen, China.
Light Sci Appl. 2022 Apr 8;11(1):89. doi: 10.1038/s41377-022-00774-z.
Functional nanostructures are exploited for a variety of cutting-edge fields including plasmonics, metasurfaces, and biosensors, just to name a few. Some applications require nanostructures with uniform feature sizes while others rely on spatially varying morphologies. However, fine manipulation of the feature size over a large area remains a substantial challenge because mainstream approaches to precise nanopatterning are based on low-throughput pixel-by-pixel processing, such as those utilizing focused beams of photons, electrons, or ions. In this work, we provide a solution toward wafer-scale, arbitrary modulation of feature size distribution by introducing a lithographic portfolio combining interference lithography (IL) and grayscale-patterned secondary exposure (SE). Employed after the high-throughput IL, a SE with patterned intensity distribution spatially modulates the dimensions of photoresist nanostructures. Based on this approach, we successfully fabricated 4-inch wafer-scale nanogratings with uniform linewidths of <5% variation, using grayscale-patterned SE to compensate for the linewidth difference caused by the Gaussian distribution of the laser beams in the IL. Besides, we also demonstrated a wafer-scale structural color painting by spatially modulating the filling ratio to achieve gradient grayscale color using SE.
功能纳米结构被应用于包括等离激元学、超表面和生物传感器等在内的各种前沿领域，仅举几例。一些应用需要具有均匀特征尺寸的纳米结构，而其他一些则依赖于空间变化的形态。然而，在大面积上精细控制特征尺寸仍然是一个重大挑战，因为精确纳米图案化的主流方法是基于低通量的逐像素处理，例如那些利用光子、电子或离子聚焦束的方法。在这项工作中，我们通过引入一种结合干涉光刻（IL）和灰度图案二次曝光（SE）的光刻组合，提供了一种实现晶圆级特征尺寸分布任意调制的解决方案。在高通量IL之后使用，具有图案化强度分布的SE在空间上调制光刻胶纳米结构的尺寸。基于这种方法，我们成功制造了4英寸晶圆级纳米光栅，其均匀线宽变化小于5%，使用灰度图案化SE来补偿IL中激光束高斯分布引起的线宽差异。此外，我们还通过使用SE空间调制填充率以实现梯度灰度颜色，展示了晶圆级结构彩色图案。
