定向传输干涉的长焦深表面等离激元纳米光刻技术研究

Surface plasmonic nano-lithography (SPNL) is the strong competitors of the next generation nano-lithgraphy for its high resolution, simple technology processes and needless of the expensive lithography lens. However in the existing schemes,there are some conspicuous shortcomings such as short DOF (Depth of Focus) and long exposure time. Here we present a new SPNL with long DOF and short exposure time based on the directional SP interference. The sub-wavelength metal grating with variable period will be used to realize the directional SP and form the interference patterns in the waveguide under the gratings. With the assistance of super lens the interference patterns are transmitted to the far field and imaged in the resist as a waveguide. Under the resist Ag nano-film is introduced to make up a reflective lithography structure to extend the DOF. We also research the two superlen lithography structure which would be double DOF. Based on the SP theory, hyperbolic dispersion theory and effective medium theory, a SPNL model will be built to analyze the SP excitation and transmission properties in the ultraviolet band. Based on the quantitative calculation by FDTD, the lithography structure will be designed for i/g line and 248nm with the resolution R<λ/12 and DOF >150nm. Simultaneously the related experiments will be carried out.

表面等离激元（SP）纳米光刻技术具有分辨率高、工艺简单、无需昂贵的光刻物镜等优点，是下一代纳米光刻技术的有力竞争者。不过现有SP光刻方案中，存在焦深太短以及曝光时间长、能量利用率低的问题。本项目针对上述问题提出长焦深的定向传输干涉SP纳米光刻技术方案。利用啁啾型亚波长光栅并结合SP波导结构来实现紫外波段SP定向传输，采用平面超透镜将定向激发的SP干涉图样从近场传输到远场，结合MIM波导结构实现SP波的干涉图样在光刻胶中横向导行，引入Ag纳米膜构成反射式SP光刻结构，延长焦深，并探索双超透镜曝光方案以期获得双倍焦深。拟以SP理论为基础，从双曲色散材料出发，利用等效介质模型建立长焦深光刻模型，半定性的分析紫外波段SP波的激发和在超透镜中的传输特性，采用FDTD算法定量计算，设计出i线、g线、248nm等常用光刻波段适用的SP光刻结构，分辨率优于λ/12，焦深大于150nm，并开展验证实验。

表面等离激元（SP）纳米光刻技术具有分辨率高、工艺简单、无需昂贵的光刻物镜等优点，是下一代纳米光刻技术的有力竞争者。针对现有SP光刻技术中焦深短以及能量利用率不高的问题，本项目研究了定向传输干涉的长焦深SP纳米光刻技术方案并开展验证性实验。 对多种常见金属材料在紫外波段的SP特性进行了系统的对比研究分析，可以方便紫外SP光刻材料选型和设计；研究了紫外波段金属纳米狭缝及纳米杆阵列的SP定向传输控制，消光比的最大值能达到13dB；系统研究了金属狭缝结构实现SP传输控制的基本原理，针对436nm曝光波长设计的A-A型和A-B-B-A型定向干涉光刻结构的分辨率均可达到为60nm，焦深分别达到280nm和250nm；研究了基于金属介质交替膜层结构（超透镜）的定向SP干涉光刻结构，248nm照明时光刻分辨率可以达到32nm，最高对比度达到0.995；研究了含金属反射层的定向SP干涉光刻结构，分辨率可以提高30%；研究了悬链线结构中的SP定向传输行为，设计的定向耦合器件消光比达到30.8dB@752nm；探索了利用化学方法来制备微细阵列结构的可能性，并开展SERS基底的制备和实验研究；开展了基于SP定向原理的微纳光子器件设计，设计了聚焦透镜、可调波片、分束器等。本项目相关成果可以为下一代纳米光刻技术服务，有助于推进 SP纳米光刻技术的实用化、产业化，也可为其他集成纳米光子器件设计与应用等提供参考。