近场光刻深宽比与界面稳定性的调控机理与实验研究

Rotational near-field photolithography is a new type of nano-processing technology with high through put, low cost and high resolution, which is of great significance to the integrated circuit manufacturing, micro-nano devices and so on. Based on the principle of hard disk drive, the rotational near-field photolithography technology can realize the nano-pattern processing utilizing the focusing and enhancement effect of surface plasmon polaritons (SPPs). However, the complex optical-electrical transmission mechanism on the air/photoresist interface and the optical-electrical-thermal multiphysics of SPPs result in undesirable aspect ratio and flying instability of the head-disk interface respectively. Firstly, this project will analyze the influencing factors of SPPs transmission on air/photoresist interface. A method to achieve large aspect ratio of nanostructure will be proposed by increasing the skin depth inside the photoresist and inducing the directional movement of hydrogen ion of the acid generator. Secondly, the thermal effect of SPPs on the air bearing capacity and the photoresist glass transition will be investigated. Combining with the new technology of the graphene lubrication film, a new technique for preventing the transfer of photoresist will be prevented which can improve the stability of the system. Based on the above researches, the bidirectional synergistic regulation mechanism between the aspect ratio and the interface stability induced by the coupling field of SPPs will by revealed. Finally, a new near-field photolithography method with high aspect ratio and interface stability should be proposed. This project is expected to further promote the application of the rotational near-field photolithography system, which will help to improve the level of nanoscale manufacturing in China.

旋转式近场光刻是一种新型高效、低成本、超分辨纳米加工技术，对集成电路、微纳器件等制造具有重要意义。该技术基于硬盘飞行原理，利用表面等离激元（SPPs）聚束效应实现纳米加工。SPPs会诱发头盘界面光、电、热场变化，其光、电场在空气/光刻胶界面的复杂传播机制会限制近场光刻的深宽比，而热效应则易引发光刻头刻蚀失稳。鉴于此，本项目拟先对头盘界面SPPs的传播受限机理进行分析，探索利用调控光电场分布增加光波在光刻胶内部趋肤深度并诱导产酸剂氢离子定向移动的方法，实现大深宽比纳米结构加工；再考察SPPs热效应对气浮承载力与光刻胶玻璃化转变的影响，探索利用石墨烯润滑膜等方法以防止光刻胶转移，提高系统刻蚀稳定性；在此基础上，研究多场耦合对深宽比与界面稳定性的协同调控机理，提出一种可实现大深宽比兼具界面稳定的旋转式近场光刻新方法。本研究有望进一步推进旋转式近场光刻技术的发展与应用，有助于提升我国纳米制造水平。

近场光刻因其可以获得超衍射极限分辨光斑，并在宏观尺度上加工近场范围内的纳米量级复杂图案的特点，具备作为一种新的纳米图案化方法应用于纳米制造技术的可能。然而，10 m/s以上的加工线速度势必造成光刻胶曝光时间较短，显影时溶解的光刻胶成分较少，形成结构的深宽比较低的结果。本项目主要针对基于表面等离激元聚束效应的旋转式近场光刻系统，对其中的关键技术和重要的学科问题进行了理论和实验研究。首先从表面等离激元激发原理和转移矩阵理论等相关理论出发，研究了表面等离激元在多层膜介质中的传播特点。在此基础上，设计并仿真验证了适用于多层膜介质的周期型圆环与Bowtie结构结合的表面等离激元透镜，解释了刻蚀深宽比较低的原因，并揭示了刻蚀深度受限机理。为了提高光刻头的飞行稳定性，对表面等离子体透镜的加工位置进行优化，提出了透镜加工的边缘效应影响光刻头压力分布的结论，并利用聚焦离子束加工技术实现了表面等离激元透镜的加工。最后，以磁头飞行性测试仪为基础搭建了旋转式近场光刻系统实验台，探究了在有机光刻胶盘片表面进行高景深超分辨纳米加工的可行性。