应用于纳米制造的新型电子束抗蚀剂Calixarene的工艺研究

为了满足电子束光刻（EBL）对高分辨率、性能优秀抗蚀剂的需求,研究了将Calixarene衍生物作为电子束抗蚀剂在胶液配制、电子束曝光及显影等工艺过程中的相关技术.其中电子束曝光实验在JEOL JBX-5000LS系统上进行.实验结果表明,在入射电子能量50 keV、束流50 pA的条件下,Calixarene可以方便地形成50 nm的单线、50nm等线宽与间距的图形结构.通过与常用电子束抗蚀剂的对比,总结了Calixarene在电子束光刻性能上的优缺点,并分析了其成因.作为一种新型的高分辨率电子束光刻抗蚀剂,Calixarene有望应用在纳米结构制造、纳米尺寸器件及电路的研制等领域.     

台湾研制出新颖电子束光阻材料

电子束光刻（electron beam lithography）是一种以电子束为工具的纳米制作技术,它是利用电子束在光阻上绘制纳米级图案,再经后续显影步骤,即可轻易制作出线宽仅数纳米的高解析结构。其中,高分子聚甲基丙烯酸甲酯（poly（nlethyl methacrylate,PMMA）是一种很普遍的压克力材料,它被大量应用在电子束光阻的材料上,且己商业化。     

高精度电容式位移传感器校准方法的研究

介绍一种使用激光干涉仪结合单轴精密位移台对电容式位移传感器进行校准的方法。建立了一套高精度电容式位移传感器校准装置,利用单轴精密位移台位移与电压之间的关系产生纳米级的微小位移,同时使用激光干涉仪和待校准电容式位移传感器测量单轴精密位移台的微小位移。该装置可实现电容式位移传感器线性度、测量重复性以及测量分辨率的校准。实验验证了此校准方法的准确性和实用性,对影响校准的主要因素进行了分析,其综合不确定度为2.2 nm。     

基于VB的纳米级驱动控制系统研究

压电陶瓷拨爪电机具有大行程、高速、位移分辨率高等突出优点,可以避免使用传统的二级驱动,直接实现纳米级驱动定位.利用PCI-7484数据采集卡和FAGOR自反馈光栅数显卡提供的DLL动态连接库函数及VB中的Timer控件,实现了对压电陶瓷拨爪电机的实时可编程控制以及位移信号的获取,成功地构建了纳米级驱动控制系统.经测试,该系统的位移分辨率可达10 nm.     

二维纳米位移台测量系统的搭建和实验研究

研制了压电陶瓷(PZT)驱动叠加柔性铰链运动机构的二维纳米位移台。介绍了位移系统的结构并分析了位移系统的工作位移刚度,理论和仿真结果误差在6.3%以内。根据线性干涉仪原理构建了一套激光干涉测量系统,阐述了测量系统的布局及位移测试原理并测量纳米位移台行程及定位准确性。实验结果表明:位移台在100μm行程内,x轴和y轴的测试位移为99.6μm和97.7μm。同时分析了测试系统的误差来源并评估测量系统的不确定度,得到该测量系统x轴和y轴的合成标准不确定分别为10.04 nm和13.93 nm。     

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．     

基于二维精密电容微位移传感器的二维纳米定位系统

设计并研制了一种结构小巧的纳米级精密定位平台.该系统采用正交簧片式设计,有效地抑制了正交运动的耦合,同时应用一个二维电容微位移传感器作为位移标准来对定位平台实行反馈控制,有效地克服了压电陶瓷执行机的非线性和迟滞效应.实验结果表明,该系统定位精度优于1nm,可在0.5μm×0.5μm范围内实行任意二维纳米循迹定位.给出了半径为2.5nm的圆及外接圆半径约为5nm的五角星形的定位轨迹图.该系统基本满足高精度引力实验精确定位的需求.     

偏振激光干涉仪的纳米定位系统

详细阐述了用于纳米定位的偏振激光干涉仪的原理,并介绍了基于该偏振仪的纳米定位控制方法.该方法已由实验论证,实验位移系统的最小步长实测值为5 nm.并对系统的最小位移步长、重复性和分辨率做了详细的分析,在系统环境控制条件下适用于毫米行程位移,可应用于纳米计量和纳米加工.     

新型光刻技术的现状与进展

大尺寸、细线宽、高精度、高效率、低成本成为IC产品发展的趋势,随着集成度的提高,芯片制造中最关键的制造工艺--光刻技术也面临着愈来愈多的难题.新兴的193 nm浸入式技术、157 nm极短紫外光刻(Euv)、电子束投影光刻(EPL)、纳米压印光刻等技术将是解决这些问题的关键.介绍了193nm浸入式技术、157nm光刻技术、电子束投影(EPL)光刻技术以及纳米压印光刻技术.指出纳米压印光刻技术具有生产效率高、成本低、工艺过程简单等优点,能实现分辨率达5 nm以下的水平,是最具发展前途的下一代光刻技术之一.     

电子束散射角限制投影光刻掩模研制

掩模制作是电子束散射角限制投影光刻(SCALPEL)的关键技术。通过优化工艺,制作出具有“纳米硅镶嵌结构”的低应力SiNx薄膜作为支撑;开发了电子束直写胶图形的加法工艺,在支撑薄膜上得到清晰的钨 / 铬散射体图形。研制出的SCALPEL掩模,其晶片尺寸为80mm,图形线宽达到0.1m,经缩小投影曝光得到78nm的图形分辨力。     

Fabrication and Characterization of Graphitic Carbon Nanostructures with Controllable Size,Shape, and Position

The incorporation of carbon materials in micro‐ and nanoscale devices is being widely investigated due to the promise of enhanced functionality. Challenges in the positioning and addressability of carbon nanotubes provide the motivation for the development of new processes to produce nanoscale carbon materials. Here, the fabrication of conducting, nanometer‐sized carbon structures using a combination of electron beam lithography (EBL) and carbonisation is reported. EBL is used to directly write predefined nanometer‐sized patterns in a thin layer of negative resist in controllable locations. Careful heat treatment results in carbon nanostructures with the size, shape, and location originally defined by EBL. The pyrolysis process results in significant shrinkage of the structures in the vertical direction and minimal loss in the horizontal direction. Characterization of the carbonized material indicates a structure consisting of both amorphous and graphitized carbon with low levels of oxygen. The resistivity of the material is similar to other disordered carbon materials and the resistivity is maintained from the bulk to the nanoscale. This is demonstrated by fabricating a nanoscale structure with predictable resistance. The ability to fabricate these conductive structures with known dimensions and in predefined locations can be exploited for a number of applications. Their use as nanoband electrodes is also demonstrated.     

Fabrication of sub-10 nm planar nanotips for transport experiments of biomolecules

Electron beam lithography (EBL) and lift-off process have been used to fabricate two- and three-terminal nano-devices consisting of metallic (Cr/Au, Ti/Au or Ti/Pt) arrow-shaped electrodes on Si/SiO₂, with tip separation between 100 and less than 10 nm. Standard EBL process allowed us to obtain nanotips with separation around 40 nm. In order to reduce the tip separation down to about 20 nm, before the EBL process, we used the defocused e-beam to brush the PMMA resist for a precise time (10÷40 s). A further reduction of the tip gap (less than 10 nm) is obtained by Au electroplating deposition. The nanotips were electrically characterized by current–voltage (I–V) measurements in the range ±2 V. In a typical I–V measurement in air of an “open-circuit” nanodevice, no significant current is observed (current range −10÷+10 pA, “open circuit” resistance≈1 TΩ) confirming the success of the technological process.     

High-resolution electron beam lithography and DNA nano-patterning for molecular QCA

Electron beam lithography (EBL) patterning of poly(methylmethacrylate) (PMMA) is a versatile tool for defining molecular structures on the sub-10-nm scale. We demonstrate lithographic resolution to about 5 nm using a cold-development technique. Liftoff of sub-10-nm Au nanoparticles and metal lines proves that cold development completely clears the PMMA residue on the exposed areas. Molecular liftoff is performed to pattern DNA rafts with high fidelity at linewidths of about 100 nm. High-resolution EBL and molecular liftoff can be applied to pattern Creutz-Taube molecules on the scale of a few nanometers for quantum-dot cellular automata.     

Nanopattern fabrication by tip plowing technology on 55 nm grating with stitching image method

An appropriate calibration positioning method is imperative to examine localized tip on nanoscale patterns for scanning probe microscopy (SPM). This paper is to develop a new nanofabrication processes for AFM tip positioning with image stitching method in tip plowing technology. Moreover, this paper adjusts the set-point amplitude (A(sp)) to develop the tip plowing technology for fabricating nanopattern on 55 nm grating gage of a silicon substrate. The developed image stitching program is based on an iterative closet point (ICP) algorithm which has six degrees of freedom alignment. A closed-loop piezo motor is used to tip approach and plow in Z-axis. Experimental result of fabricating nanobagua on 55 nm grating of silicon substrate show that the developed positioning processes with image stitching method verify the feasibility of repeatability for the tip plowing technology successfully. This developed method can be further performed by a commercial atomic force microscope (AFM) with CAD/CAM. This technology can also be applied in dip pen nanolithography (DPN), SPM oxidation lithography and related fabrication technology with AFM tips.     

天然准纳米针状石墨的发现及其结构表征

在新疆苏吉泉花岗岩所含团块状石墨中发现一种细长针状物，经高分辨电镜能谱分析其化学成份为碳。电子衍射数据分析表明其结构为2H多型石墨。确认该细长针状物为准纳米针状石墨，其长度可达12500nm，宽度为150nm，边缘平直，且晶面条纹平直度极高。认为这种准纳米针状石墨会具有优异的力学性质，可能是一类高强度的材料。     

Toward sub-20 nm hybrid nanofabrication by combining the molecular ruler method and electron beam lithography

It is of great interest and importance to develop new nanofabrication processes to fabricate sub-20 nm structures with sub-2 nm resolution for next-generation nanoelectronic devices. A combination of electron beam lithography (EBL) and a molecular ruler is one of the promising methods to make these fine structures. Here we successfully develop a hybrid method to fabricate sub-20 nm nanogap devices at the desired positions with a complex structure by developing a post-EBL process, which enabled us to avoid damaging the molecular ruler with the high-energy electron beam, and to fully utilize the EBL resolution. It was found that slight etching of the Ti adhesion layer of the parent metal (Pt) by ACT935J solution assisted the removal of molecular rulers, resulting in improved enhancement in the product yield (over 70%) of nanogap devices.     

Small angle X-ray scattering measurements of spatial dependent linewidth in dense nanoline gratings

Small angle X-ray scattering (SAXS) was used to characterize the cross section of nanoline gratings fabricated with electron beam lithography (EBL) patterning followed by anisotropic wet etching into a single crystal silicon substrate. SAXS results at normal incidence clearly bear the signature of positional dependent linewidth within the gratings; such non-uniformity is subsequently confirmed with scanning electron microscopy. The proximity effect of EBL is believed to be the cause of the spatial variations of linewidth. To quantitatively fit the SAXS results the linewidth near the periphery of the patterned field needs to be 80% greater than that in the central region, whereas the cross section of nanolines can be modeled as a simple rectangular shape, as expected from the anisotropic wet etching process.     

Advanced patterning techniques for nanodevice fabrication

The key elements in the fabrication of future devices are lithography and pattern transfer. The continuous advances in miniaturization and increasing integration densities are a direct result of improved lithographic resolution and overlay accuracy. Electron beam direct write and e-beam projection lithography are potential candidates for the mass production of microelectronic devices with critical dimensions below 100 nm. To realize these nanometer patterns by this technology, the performance of exposure tools and resist materials should be increased. In this paper, the method of direct write e-beam lithography is demonstrated and critical issues are discussed.     

EBL- and AFM-based techniques for nanowires fabrication on Si/SiGe

Two approaches for sub-100 nm patterning are applied to Si/SiGe samples.The first one combines electron beam lithography (EBL) and anisotropic wet etching to fabricate wires with triangular section whose top width is narrower than the beam size. Widths as small as 20 nm on silicon and 60 nm on Si/SiGe heterostructures are obtained.The second lithographic approach is based on the local anodization of an aluminum film induced by an atomic force scanning probe. Using atomic force microscopy (AFM) anodization and selective wet etching, aluminum and aluminum oxide nanostructures are obtained and used as masks for reactive ion etching (RIE). Sub-100 nm wide wires are fabricated on Si/SiGe substrates.