【作者】 林宏；

【导师】 印杰；

【作者基本信息】 上海交通大学 ， 高分子化学与物理， 2012， 博士

【摘要】 紫外纳米压印技术基于机械压印原理，具有避免使用昂贵的光源及投影光学系统，不受光学光刻的最短曝光波长的物理限制和工艺简便等特点，在下一代纳米图形加工技术中脱颖而出，引起了人们广泛的关注。目前，纳米压印技术己经应用到光探测器、晶带板、以及柔性电路板、有机电子装置、LED封装、具有以及高密度数据存储器的研究。在欧盟提出的DONDODEM计划中，也对纳米压印光刻技术给予了支持，该计划旨在形成一套纳米压印光刻技术的工艺规范和工业标准，以促进其早日在工业界得到广泛应用。在紫外压印工艺中，压印成像用的光刻胶是该技术成功的关键之一，光刻胶的粘性，湿度，紫外光聚合的动力学，还有刻蚀的选择性等都是需要关注的问题，需要不断开发新的光刻胶体系。本论文结合目前的紫外纳米压印技术，针对目前紫外纳米压印胶的一些缺陷，探索和设计了不同类型的紫外纳米压印胶，并深入研究了其性能与结构之间的关系，并将之进一步应用到纳米压印及其图形转移、以及软模板制备中。一、开发出一种基于硫一烯点击化学的新型的有机一无机杂化的紫外纳米压印胶JTHc—a。合成了基于巯基的P0ss—sH，相对于商业用的巯基化合物，挥发性小、且是有机无机杂化的分子级的功能化材料。将P0ss—sH和传统的甲基丙烯酸酯类化合物组合形成硫一烯类紫外光刻胶JTHc_a，该上海交通大学博士学位论文体系透明均一，稳定性好，有良好的储存性能。全文系统研究和考察了压印胶的组份及其聚合物膜的性能，整个光刻胶体系具有较低的粘度(6．1—24．4 cP)，及其适合低压压印，同时P()SS的掺入大大提高了光刻胶的抗氧刻蚀性能和热稳定性能。通过红外和PhotoI)sc的原位跟踪检测，该光刻胶的光聚合过程中有效降低了氧阻聚作用，提高了碳碳双键转化率(93％)，同时降低了光刻胶聚合后的本体收缩率(5．3％)。将优化后的压印胶JTHc—al用于紫外纳米压印，成功的压印出从微米到l00纳米尺寸的结构，并将之应用到图形转移中，能得到高分辨率的硅纳米图案。二、基于硫一烯点击化学的作为紫外压印胶的优点，进一步开发出一种基于硫一烯点击化学的含氟的紫外压印胶JTHc_b，并将之用于制备软模板。通过对含巯基的低倍多聚硅氧烷化合物(POSS—sH)巯基端基嫁接低表面能的氟化官能团，将硫一烯点击化学和POSS氟化物(P()SS—F—sH)的优势结合起来，开发出一种基于硫一烯点击化学的含氟的紫外压印胶JTHc_b。该光刻胶由POSS—F—sH，双官能团的含氟甲基丙烯酸酯DcFA。作为交联剂，和光引发剂I一907按一定摩尔比混合组成。这种基于硫一烯点击化学的光刻胶，具备紫外压印胶优异的品质，包括低粘度(16—239 cP)、低本体收缩率(4．8—7．5％)、以及极好的抗氧阻聚性能。此外，与传统的PI)MS软模板相比，JTHc_b软模板具有低表面张力(14—20．4 mJM-5)、高脱模效率、高透光率、高机械强度(0．3l—1．56 GPa)以及较高的热稳定性(Td>：300℃)，并且进一步将此软模板应用于商业紫外光刻胶的压印中，得到很好的脱模效果以及大范围高精细的微纳米图形(200 nm一3．9um)。软模板在高温及不同压力下反复套用10次后，表现出较强的机械性能，模板没有撕裂和结构破损。这种经济的软模板制备方法，以及较强的机械性能和脱模性能使得该软模板具有在大规模微纳米器件制造中存在着潜在的价值。三、首次报道了一种基于硫一炔点击化学的含POSS的杂化紫外压印胶JTHc—c。这种基于硫一炔化学的体系比硫一烯体系具有更高的交联密度和玻璃化温度。整个光刻胶由双功能化的POSS—sH一0A，双官能团炔烃组成。整个体系透明均一，稳定性好，有良好的储存性能。P()SS—sH一0A的掺入能有效降低聚合后的本体收缩率(0．8—4．8％)，大大提高了光刻胶的抗氧刻蚀性能以及热稳定性。同时，聚丙二醇类炔烃(PPGY)的加入能提高疏水性能(水接触角>90。C)，这种基于硫一炔点击化学的光刻胶还因为其反应速度快，且具有低粘度(127一198 cP)、便于旋涂涂覆，极其适合低压压印。本章系统考察和优化了压印胶的组份，成功的压印出高精的微纳米图形，并将之应用到图形转移中，能得到高深宽比的硅纳米图案。四、为了进一步提高模板的利用效率，我们设计了一种可擦除的紫外压印胶。首先合成出具有光可逆功能的带有丙烯酸酯官能团的香豆素衍生物AHEMc作为交联剂。进一步的组合了光可逆紫外纳米压印胶，并对光可逆紫外压印胶的优化~‘11’眭1能进行了表征。通过uV_vis光谱的跟踪检测，可逆胶具有明显的光可逆性能。并且优化后的光可逆压印胶通过光二聚和解聚后，可以溶解在氯仿溶剂中，从而达到了很容易在模板表面清洗的目的。通过紫外纳米压印，AMP—10G—AHEMc光可逆胶能够大范围的压印出高精度的微纳米图形，同时和商业胶的抗sF6刻蚀性能做了对比，表现出极好的抗sF6性能，说明AMP—10G—AHEMc可逆压印胶的机械性能和抗刻蚀性能完全可以作为商用压印胶应用到纳米压印技术中。更多还原

【Abstract】 UV nanoimprint lithography (UV-NIL) has gained increasing attention as a next-generation patterning technique that allows the fabrication of nanostructures with high resolution, and that offers a complementary alternative to traditional photolithography. Due to its facile, cost-effective, and high-throughput production processes, UV-NIL technology has been successfully used in the fabrication of electric and optical devices, such as light-emitting diodes and optical-disk storage devices, and in biological applications. NIL technology is listed in the International Technology Roadmap for Semicon-ductors for 22 nm half-pitch manufacturing. Despite the achievements in NIL technology, its progress has been limited by the availability of suitable resist materials. There are many factors will be considered, for example: the viscosity, humidity, the kinetic of the reaction and the etching resistance of the resist. To fully explore the potential of UV-curable resist and increase its versatility, it is desirable to develop new resist materials. In this thesis, we developed several types of organic-inorganic composite photoresists. Meanwihle, the relationship between the properties and the structure of the resists had been studied. Furthermore, the novel photoresists were sucessfully applied in UV-NIL, pattern transfer or the fabrication of the soft- mold.1. A novel hybrid resist for UV-NIL based on the thiol-ene photopolymerization, which is comprised of mercaptopropyl polyhedral oligomeric silsesquioxane (POSS-SH), diluted benzyl methacrylate (BMA) and crosslinker trimethylolpropane trimethacrylate (TMPT). The obtained hybrid resists possess a variety of characteristics desirable for UV-NIL, including low viscosity (6.1-24.4 cP), low bulk volumetric shrinkage (5.3%), high Young’s modulus (0.9-5.2 GPa), high thermal stability and excellent dry etch resistance. Based on these performances, optimized component were evaluated as UV-NIL resist. The resultant pattern exhibited the high resolution pattern with feature sizes in the range of 100 nm to several microns. The double-layer resist approach is used for pattern transfer into silicon substrates. Due to excellent oxygen etch resistance of the etch barrier material, the final height of the transfer pattern is about 3 times more than that of the original NIL pattern.2. A novel fluorinated hybrid resist as soft mold for NIL based on the thiol-ene photopolymerization was precisely designed and synthesized, which is comprised of fluorinated mercaptopropyl polyhedral oligomeric silsesquioxane (POSS-F-SH), diluted crosslinker 2,2,3,3,4,4,5,5-octafluoro-1,6-hexyl diacrylate (DCFA4). The obtained fluorinated hybrid resists possess a variety of characteristics desirable for UV-NIL, including low viscosity (16-239 cP), low bulk volumetric shrinkage (4.8-7.5%) and a good resistance to oxygen inhibition. The cross-linked hybrid resins exhibited high transparency to UV light and resistance to organic solvents. As soft mold, the excellent mechanical property (Young’s modulus 0.31-1.56 GPa) and low surface energy (14-20.4 mJ/m-2) of the fluorinated polymers provided a clean mold release without fracture or deformation of the embossed structures. The thermally stability (Td >300 C) render them capable of being used for both UV and thermal NIL duplication processes. The resultant soft mold exhibited the high resolution patterning capacity with feature sizes in the range of 200 nm to several microns. After repeating 10 imprinting cycles at relatively high temperature and pressure, no detectable crack or contamination of the replica surface was observed. The economic efficiency of the mold fabrication as well as the high durability and excellent releasing properties could be quite valuable to NIL for high-throughput fabrication of nano-devices. 3. A novel hybrid resist for UV-NIL was precisely designed, and the radical-mediated thiol-yne step-growth photopolymerizations are utilized to form highly cross-linked polymer networks. The resist is comprised of mercaptopropyl and Octyl group bifunctional polyhedral oligomeric silsesquioxane (POSS-SH-OA), diluted crosslinker difunctional alkyne. The obtained hybrid resists possess numerous desirable characteristics for UV-NIL, such as great coatability, high thermal stability, hydrophobicity (water contact angle > 90 ), low bulk volumetric shrinkage (0.8~4.8%), and excellent dry etch resistance. In particular, the process of thiol-yne system allows the resists to be solidi ed within seconds under UV exposure at room temperature, Furthermore, due to excellent oxygen etch resistance of the etch barrier material, the final height of the transfer pattern is about 3 times more than that of the original NIL pattern.4. We designed a novel photo-reversible resist for UV-NIL which is comprised of a photo-reversible cross-linker (2-[(4-methyl-2-oxo-2h-1-benzo- pyran-7-yl)oxy] ethyl ester, AHEMC). Under exposure of 365 nm UV-light, this photo-reversible resist can form crosslinked network via radical polymerization of acrylate groups and photodimerization of coumarin moieties. The formed polymer networks containing coumarin dimer moieties could be degraded via illumination of point light source (254 nm). The reversibility of crosslinked system was helpful to refresh mold easily and release the adhered curing resist at room temperature.更多还原