纳米光刻技术在纳米光子晶体、超材料和生物学中的应用

【作者】 陆冰睿；

【导师】 刘冉；

【作者基本信息】 复旦大学 ， 微电子学与固体电子学， 2010， 博士

【摘要】 纳米科技是20世纪80年代末逐步发展起来的一门新兴的前沿交叉学科领域,纳米电子学、纳米光学、纳米材料、纳米机械、纳米生物学共同组成的纳米高技术群体大大拓展和深化了人们对客观世界的认识,并将带来新一轮的技术革命。而纳米加工技术则是使各领域内纳米研究摆脱纸上谈兵而得以实验实现的基础。目前纳米图形制作的主要途径有两个：一是自下而上的途径,采用现代化学技术,由单个原子聚积而成的自组装方式。另一是自上而下的途径,采用光刻手段在物体上制作纳米量级图形,但这需要大幅度提高现有光刻的分辨率。本论文主要讲述自上而下的方法进行纳米光刻技术的工艺加工手段以及在此基础上对不同纳米结构的研究。研究对高分辨率电子束光刻、纳米压印技术、近场纳米超分辨率光刻、纳米反压印光刻技术以及与之配套的后道纳米工艺包括金属淀积、金属剥离和各项检测手段进行了具体研究,并将由此技术制备的器件用于纳米光学、纳米生物学和纳米材料学等领域的交叉研究,获得了成功的实验和测试结果。文章从发展最完善的纳米光刻技术之一电子束光刻出发,深入系统地介绍了电子束光刻系统的工作原理,对著名厂商的代表性产品进行了比较和分析。在对其原理有了具体系统了解的基础上,利用电子束光刻对一种新型的电子束光刻化学放大胶Uv1116进行了系统的特性研究,从光刻胶的灵敏度、对比度、分辨率和抗腐蚀特性等多角度深入分析,并与其前身、当前广泛使用的UⅧ光刻胶进行了比较,分析各方面的改进,肯定了其在纳米光刻领域广泛的应用前景。在将纳米光刻技术与生命科学、材料科学相结合的工作中,首次将电子束光刻的技术用于对材料的表面改性,利用电子束激发改变衬底材料的杨氏模量,在此基础上改变附着人体骨髓干细胞的生长微环境,从而影响干细胞的分化,并获得成功的特异性分化结果。同时,又将电子束光刻和纳米光学技术相结合,利用电子束光刻制备了多种具有不同对称度的纳米准光子晶体结构,并在这些结构的研究基础上进一步完善,开发设计了一种三维两相环形准晶纳米透镜系统,为此设计并实施了两种不同的新型自对准纳米光刻工艺,制备所得的三维准晶纳米透镜,可以达到超越传统极限的超高光学分辨率。另一方面,还对电子束光刻工艺的本身进行了细致的研究,针对不同光刻胶的电子束光刻流程和工艺参数进行了分别的测试和设计,并将电子束光刻工艺的用途发挥至其他纳米光刻工艺的领域。利用电子束光刻制备了光栅结构和光子晶体及超材料结构,用于纳米压印光刻的模板和近场纳米光刻的掩模板,并利用该模板进行进一步的纳米光刻实验。在对纳米压印光刻的研究中,对纳米压印的工艺流程和参数进行了细致的研究,确定了不同参数对纳米压印的影响从而确定了最佳实验条件,制备了具有介质或金属等不同材料单元的平面手性光子晶体超材料结构,并进行了大量的光学实验,对其特殊的光学性质进行了测量和分析。通过大量细致的实验数据总结了光子晶体中特殊的单元结构对其衍射场分布的影响,并证实了具有手性单元的超材料结构对偏振光的特殊调控作用。在近场纳米光刻的研究中,对不同尺寸和结构的光刻掩模版图形在光刻中的出射的紫外光的光强分布进行了软件模拟,了解了隐失波在近场光刻中的作用,并以此为基础设计了一种全新的纳米光刻技术,将近场纳米光刻工艺和纳米反压印光刻工艺相结合,利用近场隐失波对旋涂于掩模板上的光刻胶进行光学光刻,再通过纳米反压印的方式将光刻胶图形转移至所需衬底上,利用传统的光学光刻的方式和紫外光源在任意衬底上实现了超高分辨率的纳米图形,对衬底的材料和形状都没有苛刻的条件。最后,首次实现了在非平面衬底如光纤截面顶端实现大面积图形的均匀转移,并通过初步的光学实验证实了其功能可靠性。这一全新的纳米光刻工艺具有快速高效成本低廉的优良性质,将在实验室研究和工业生产中均具有广阔的应用前景。在本论文研究中发展起来的纳米技术和纳米科学的结果,建立起了一个较为完善的纳米光刻研究体系,可以作为复旦大学在这个领域的纳米科研的技术基础,为进一步的纳米科学的基础研究的深入开展提供支撑和依据。更多还原

【Abstract】 Nanotechnology is a new brand of interdisciplinary scientific research field that has gradually but quickly developed since the late 1980s. It consists of the theoretical and experimental study of different research fields such as nano-electronics, nano-optics, nano-material, NEMS (nano-electro-mechanical systems) and nano-biology. This study significantly broadens people’s understanding towards the world around us and plays an important role in the new round of technological revolution in this era. While nanotechnology is the hot topic in research, nano-fabrication techniques are the methods to take the theory into action. There are two main methods for nano-fabrications. One is the bottom-up method, which utilize the modern chemical assembling technology to build up nanostructures through atom and molecu manipulation. The other is the top-down method, which employ nanolithography for the patterning on different substrates, where the resolution is a critical element.This thesis focuses on the top-down nanofabrication method and the scientific study on different nanostructures fabricated by this method during the work. It studies the high resolution electron beam lithography, nanoimprint lithography, near-field lithography, reversal imprint lithography and relatd nano processes including metallization, lift-off and inspection methods. With the nanodevices fabricated during the work, further experimental studies in nano-optics, nano-biology and nano-material sciences are carried out and promising results are obtained.The study starts with one of the most developed nanolithography methods, e-beam lithography. The working principle of the e-beam lithography system is investigated, and different systems from some famous suppliers are compared. With the comprehensive knowledge os the e-beam system, a characterization study for a new chemically amplified resist (CAR) named UV1116 is carried out with respects of the sensitivity, contrast, resolution and dry etching properties of the resist. The improvement of the resist has been confirmed through comparison with its predecessor UVIII resist, which give rise to a broad application of UV1116 in nanolithography. In the study of combining nanolithography technology with life science and material science, we for the first time employ electron beam irradiation in material surface property engineering. Electron beam is used to irradiate the Young’s modulus of the substrate surface and therefore change the micro-environment for the growth of human marrow stem cells, leading to a successful differentiation of the stem cells.Meanwhile, e-beam lithography is also combined with nano-optics. We use e-beam lithography to fabricate nano quasi-crystal structures with different sysmetrical folds. Based on the study of these nano quasi-crystal structures, a new binary-phase annular ring mask structure is designed to achieve infinite-fold quasi-crystal structures. In order to fabricate such unique structure, two different methods with self-aligned nanolithography process are developed to achieve the high accuracy of the structure. The fabricated structure is expected to attain resolution that beyond the diffraction limit.On the other hand, a comprehensive study for the electron beam lithography itself has also been carried out. Process flows and parameters for different e-beam lithography resists are designed and tested respectively. The strctures fabricated are further employed in other nanolithography fields such as nanoimprint lithography and near-field lithography.In nanoimprint lithography, systematical study in the influence of nanoimprint parameters on the imprinted structures are carried out and the optimized nanoimprint parameters are set. With the optimized parameters, nanophotonic crystal structures with both dielectric and metallic chiral elements metamaterial structures are fabricated and subsequent optical measurements are carried out afterwards. It is concluded that the special elements in the photonic crystal structures has unique influence in the distribution field of the diffraction. And the manipulation for polarized light of metamaterial with chiral elements has been confirmed.In the research of near-field lithography, FDTD simulations for the distribution of the light intensity when it shines on and passes throught the lithography mask with different patterns and feature sizes are compared. A new optical nanolithography method is developed, combining near-field lithography and reversal imprint lithography. In this optical nanolithograhy method, the theory of evanescent field is employed for the exposure of resist which is spin coated on the mask plate intead of the substrate. The exposed and developed resist with nano patterns is transferred onto the substrate by reversal imprint lithography. In this way, high resolution nano patterns can be achieved on almost all kinds of substrates with different material and shapes by conventional optical lithography method. What’s more, nano patterns on the tip of the opcial fiber are fabricated for the first time in the world. Preliminary optical measurements prove good performance of the fabricated structures on the fiber tip. This new optical nanolithography method is low cost but can achieve high volumn productivity. It has great potential in both lab research and industial mass production fields.The technological and scientific achievements made in this research have built up an integrated study system for nanolithography and opened up a brand new field in nanotechnology and nanoscience. The results can be used as a foundation for the nanoscience research in Fudan University in this field and be provided as support and basis for a thorough research in the future.更多还原