Laser heat-mode patterning with improved aspect-ratio

Heat-mode lithography has received much attention owing to its capacity of breaking through the diffraction limit and realizing nano-patterning. However, the relatively lower aspect ratio of patterns seriously limits its scope of applications. In the currently available literature, the aspect ratio of submicron structures prepared by this method is less than 0.3:1. In this work, a new two-step development process was proposed to considerably improve the aspect-ratio of micro/nanostructures in the AgInSbTe (AIST) heat-mode resist. An aspect ratio of 1:1 can be kept even for the grating structures with a linewidth/period of 200nm/400nm. The developed patterns can be transferred to silicon substrates with high fidelity. This simple and effective technique addresses key issues of heat-mode lithography in the manufacture of functional nanostructures requiring high aspect ratio, such as photomasks, templets of nanoimprint, and so on.

热模式光刻（Heat-mode lithography）因能够突破衍射极限、实现纳米图案化而受到广泛关注，但现有图案的较低纵横比严重限制了其应用范围。当前公开文献显示，采用该方法制备的亚微米结构的纵横比均低于0.3:1。本研究提出一种新型两步显影工艺，可大幅提升AgInSbTe（AIST）热模式光刻胶中微纳结构的纵横比：即便对于线宽/周期为200nm/400nm的光栅结构，仍可维持1:1的纵横比。所显影得到的图案可高保真地转移至硅衬底。这一简便高效的技术解决了热模式光刻在制备高纵横比功能纳米结构（如光掩模、纳米压印模板等）时面临的核心难题。