超分辨、长焦深的SPP扫描光刻技术研究

Surface plasmon polariton(SPP) scanning lithography is a flexible, low-cost, and high resolution technology. Localized surface plasmon generated by nano-optical antenna can produce patterns with nanoscale resolution far beyond the diffraction limit. However, this technique is plagued by short focal depth, therefore the lithography exposure depth is very shallow. This drawback limits its application in many fields. In this report, we propose a method to enhance the focus distance of excitation field without sacrificing its resolution by combining hyperbolic metamaterial and light field reconstruction technique. A high resolution, large exposure depth and non-contact scanning lithography method will be developed. Results from this research will not only solve key problems of plasmonic direct scanning lithography but also strengthen the manufacturing foundation of our country for future technology growth. The proposal work, if successful, will have a large impact on nano-manufacturing technology as well as nano-science and nano-technology in general.

基于表面等离激元(SPP)的直写扫描光刻是一种灵活、低成本、高分辨的光刻技术。原理上这种技术基于亚波长纳米光学结构产生局域场，从而曝光光刻胶产生远超衍射极限的光刻分辨率。但是现有SPP超分辨扫描光刻具有短焦深的特点，使得这种扫描光刻的曝光深度很浅，因而严重制约了这项技术的广泛应用。本项目拟结合双曲色散材料与基于菲涅尔波带片的光场重构方法，在保证光刻分辨率的同时，提高光刻的曝光深度，进而在此基础上发展超分辨率、长焦深、非接触式的直写扫描光刻技术。本项目的研究，不仅有望解决现有表面等离激元直写扫描光刻中关键的原理性问题，而且有助于研制具有自主核心技术的纳米光刻技术、实现微纳结构器件与材料低成本制造，对推动我国纳米新产品开发和行业技术进步有重大意义。

表面等离激元(SPP)的光场局域和增强特性可用来实现高分辨纳米光刻应用。相比传统纳米图案制备方法，基于SPP的直写扫描光刻是一种灵活、低成本的光刻技术。但由于SPP的近场特性，其<10 nm的曝光深度（短焦深）的缺点严重制约了该技术的广泛应用。本项目利用金属-介质-金属共振腔、双曲色散材料等人工超材料体系实现蝶形纳米孔径天线局域光场出射后的再调制，在获得深亚波长分辨率的同时，可以将光刻焦深提升至100 nm；此外，采用基于菲涅尔波带片的光场重构方法，将光刻焦深进一步提升至500 nm，实现超长焦深扫描光刻。项目资助期间，共发表SCI论文8篇，申请专利6项（授权2项），培养博士4名、硕士1名，项目人员在国际会议上发表论文/做报告4次。项目研究成果解决了SPP直写扫描光刻中焦深不足的弊端，进一步提升了该方法的实用性，在极限纳米加工和光学功能材料制备领域具有重要应用价值。