纳米光子结构软膜紫外光固化纳米压印

紫外光固化纳米压印是实现纳米结构批量复制的一种新技术．其特点是低成本和高分辨，而且可以达到极高的套刻精度．为了得到大面积图案的均匀复制，可用聚二甲基硅氧烷（PDMS）制备透光的压印软模板．其母版图案可由高分辨率电子柬曝光和反应离子刻蚀的方法在硅片基底上获得，然后用浇注的方法将图案转移到PDMS上．本实验特别发展了紫外光固化纳米压印适用于软膜压印的双层膜图型转移技术．该双层膜由廉价的光胶和聚甲基丙烯酸甲脂（PMMA）构成．对光胶层的压印可用普通的光学曝光仪实现．然后再将图案用反应离子刻蚀的方法转移到PMMA层中．为了证明方案的可行性，在两种不同材料的半导体基片上压印了三角晶格的光子晶体和准晶结构的图案，并用剥离的方法将它们转移到金属薄膜上，最后成功地进行了硅片刻蚀实验．相信这一纳米制做方法对大面积纳米光子结构和光学集成芯片的制造是普遍适用的．

Fabrication of Nanophotonic Structures by Soft UV Nanoimprint Lithography

Nanoimprint lithography assisted by UV solidification is a new technique to pattern nanostructures by replica- tion.It is low cost and high resolution with the possibility to achieve very alignment accuracy.In order to obtain good pat- tern homogeneity over large areas,soft transparent molds can be made of polydimethylsiloxane(PDMS)by casting on a sili- con mater defined by high resolution electron beam lithography and reactive ions etch techniques.This work is devoted to a general bi-layer resist pattern transfer process which is compatible to the soft UV nanoimprint lithography.The bi-layer sys- tem we used consists of a low cost photo-curable polymer and a PMMA buffer layer.Imprinting has been done using a nor- mal photolithography aligner.Then,the imprinted patterns have been transferred into the PMMA laser by reactive ion etch- ing.To demonstrate the process feasibility,photonic crystals of both triangle and quasi-crystal lattices were patterned on two types of semiconductor substrates by soft UV nanoimprint and transferred by lift-off with a thin metal layer.Finally,re- active ion etch has been achieved with the patterned silicon wafer.We believe that this fabrication process is versatile for the manufacturing of large area photonic nanostructures as well as optical integrated circuits.