基于AFM硅表面局域阳极氧化的特性研究及纳米计量标准样板的制作

基于原子力显微镜(AFM)在硅(Si)表面进行局域阳极氧化的技术,以其成本低、易加工等优势被广泛应用于各种纳米元器件的制造.本文基于AFM在Si表面进行局域阳极氧化来制作纳米计量标准样板,首先分别在接触模式和轻敲模式下进行实验,定量分析了偏置电压、移动速率和刻蚀方向等主要参数对所得纳米线尺寸的影响,从而得到标准样板制作的最佳加工参数:在探针针尖电压为-7 V、移动速率为0.3μm/s、Z Distance值为-45 nm时,可以产生稳定的标准样板结构;同时两种模式下对纳米氧化线的影响趋势相同.最后在此最佳参数下,利用AFM在Si表面进行局域阳极氧化,加工得到了一维线光栅、二维光栅和圆形光栅结构.     

使用SPM的纳米级加工技术新进展

扫描探针显微镜(SPM)现在不仅用于表面微观形貌的检测，同时也用于纳米超精密加工和原子操纵，该文介绍了用STM和AFM进行纳米级加工的各种最新方法：针尖直接雕刻，针尖光刻加工，局部阳极氧化，原子沉积形成纳米点，原子去除形成沟槽微结构，多针尖加工，原子自组装形成三维结构等．使用SPM的纳米级加工对发展微型机械、纳米电子学和微机电系统具有重要意义．     

软膜紫外光固化纳米压印中Amonil光刻胶的刻蚀参数优化(英文)

报道了反应离子刻蚀转移图形过程中对Amonil光刻胶的刻蚀参数优化的结果.利用软膜紫外光固化纳米压印技术,首先制备了线宽/间距均为200 nm的纳米光栅结构.然后采用反应离子刻蚀的方法去除残留的Amonil光刻胶.研究了不同的气体组成、射频功率、压强和气体流量对刻蚀形貌、表面粗糙度以及刻蚀速度的影响.在优化的工艺条件下,获得了理想的具有垂直侧壁形貌和较小表面粗糙度的纳米光栅阵列.结果表明,选择优化的刻蚀工艺参数,既能有效地改善图形转移的性能,同时也能提高所制备结构的光学应用特性.     

一种大面积二维石英纳米结构制备的工艺研究

介绍一种采用紫外(363.8nm)激光干涉光刻得到大面积二维纳米点阵结构的方法,该技术具有操作简单、光路搭建成本低、可以大面积加工微纳图形结构等优点;并利用等离子体刻蚀传递,获得周期为200nm的二维石英纳米点阵结构。通过光刻工艺与反应离子束刻蚀工艺的优化,得到加工二维石英点阵的最优制备工艺。利用扫描电子显微镜(SEM)与原子力显微镜(AFM)对制备二维纳米图形结构进行表征与分析,并利用紫外可见光分光光度计对制备的二维点阵结构图形进行紫外透过率测试,发现加工的二维结构在365nm处的透过率仍大于90%,符合紫外固化纳米印掩模板对紫外光高透过率的要求。     

基于NMM的AFM测试分析原子光刻纳米光栅样板

利用激光汇聚中性铬原子沉积出一维纳米光栅样板的基础上,基于 NMM的AFM测量系统对样板进行了测试分析和测试方法研究,得到一维纳米光栅结构平均节距为212.6±0 4nm,与52Cr原子共振跃迁(7S3→7P04)的半波长(λ/2)理论值212.8nm基本一致,测试结果非常准确.文章还介绍利用NMM测量机的大范围扫描测试距离,解决了光栅样板的测试区域快速定位的问题,对研究纳米级精度测量有实用价值及参考意义.     

基于X光光刻的亚波长光栅

描述了一种新的亚波长光栅的微细加工技术，即X光光刻得到相应的亚微米级的线宽图形，再利用显影技术获得了高深宽比的立体亚波长光栅．用此纳米加工技术获得了栅距为500nm、250nm、150nm，光栅高度为1900nm的特殊纳米光栅模具，开发了纳米无反射结构，并研制成功了亚波长光栅．该亚微米线宽微细加工技术可用于布拉格光栅、DVD读写头、无反射表面等需要亚微米结构的器件中．     

微波ECR等离子体刻蚀AAO模板中HfO_2薄膜的研究

采用微波电子回旋共振(ECR)等离子体装置,对用原子层沉积(ALD)方法在阳极氧化铝模板(AAO)上制备的HfO_2薄膜进行了纳米图案化研究。用CF_4、Ar和O_2等离子体,对HfO_2薄膜进行了反应离子束刻蚀,以移除HfO_2。采用高分辨率扫描电子显微镜(SEM)、原子力显微镜(AFM)和能量色散X射线光谱显微(EDX)分析,对样品刻蚀前后的形貌、结构和化学成分进行了表征。实验表明,HfO_2的刻蚀具有定向性,利于高深宽比微机械结构的加工。在其他参数固定的情况下,深宽比高达10∶1的结构中HfO_2的刻蚀速率是微波功率、负脉冲偏压、CF_4/Ar/O_2混合比(Ar含量在0～100%)和工作气压的函数。在0.3 Pa气压、600 W微波功率、100 V偏置电压下,HfO_2拥有0.36 nm/min的可控刻蚀速率,利于HfO_2的精准图案化。刻蚀形貌表明,在CF_4/Ar/O_2等离子体刻蚀之后,刻蚀面非常光滑,具有0.17 nm的均方根线粗糙度。     

原子力显微镜探针针尖修饰的研究进展

介绍了当前几种AFM探针针尖修饰技术,以及它们在高分子材料、生物材料、微观摩擦学、粘附力、纳米级电化学、碳纳米管及纳米加工方面的研究进展。AFM探针针尖修饰的目的主要是:提高扫描图像分辨率,其分辨率可达纳米或亚纳米级别;用力曲线探究特定基团间的相互作用,定量分析端基与端基之间、分子链与分子链之间及端基与分子链之间的相互作用力,避免针尖对生物样品表面的损坏;对分子材料结构进行修饰,特别是在生物细胞、DNA分子链上及分子识别;避免Si或Si3N4针尖与表面硬度较大的样品直接接触,延长探针针尖的使用寿命。在研究天然橡胶硫化的作用机理时,可以用针尖修饰技术来模拟这个过程,探究天然橡胶分子链与单个硫原子的相互作用方式与作用力。通过电化学接枝聚合把高分子接枝在AFM针尖上,为研究单链的弹性力、引起构象转变的力、相互作用的双分子的分离力及特定的官能团的相互作用提供了许多可能性。分析了影响AFM探针针尖修饰的因素,结合材料领域方面的发展,对针尖修饰技术的发展及应用前景做了分析和预测。     

FPN的影响因素分析及相关应用

钢笔纳米刻蚀技术(Fountain pen nanolithography,FPN)是近年来发展起来的一种新型的基于原子力显微镜(Atomic force microscope,AFM)的扫描探针刻蚀技术,具有加工结构精度高、加工过程操作性强、对加工环境要求低、持续书写等优点。FPN刻蚀过程主要受探针的孔径大小、空气湿度、接触时间、书写速度、墨水的特性等因素影响。在介绍FPN相关原理及影响因素的基础上,综合介绍了包括电化学FPN技术(Electrochemical FPN,EcFPN)和主动控制技术FPN(Active FPN,AFPN)在内的FPN相关技术研究的最新成果及其在生物领域、微电子领域和光学器件方面的相关应用。     

基于Cr原子光刻技术的nm光栅间距比对测量定值方法研究

建立了一种基于Cr原子光刻技术的nm光栅间距比对测量定值方法。以国家自溯源光栅标准物质来建立标准样板校准溯源体系的可行性为基础,保障测量仪器更高精度、可溯源性;设计并制备了节距长度有序递增的多周期电子束直写光栅样板,满足可适配于不同分辨率的nm测量仪器的需求,名义节距值分别为200、400、600、800、1 000 nm。经国家自溯源光栅标准物质比对后的AFM完成对nm栅格标准样板的测量与表征,实验表明：电子束直写制备的光栅标准样板均匀性水平1 nm,相对不确定度低于2%,光栅均具有良好的均匀性、准确性以及稳定性,验证了研制的光栅标准样板能作为一种理想的实物标准运用于nm几何量量值溯源体系。     

Combined AFM nano-machining and reactive ion etching to fabricate high aspect ratio structures

In this paper, a new combined method of sub-micron high aspect ratio structure fabrication is developed which can be used for production of nano imprint template. The process includes atomic force microscope (AFM) scratch nano-machining and reactive ion etching (RIE) fabrication. First, 40 nm aluminum film was deposited on the silicon substrate by magnetron sputtering, and then sub-micron grooves were fabricated on the aluminum film by nano scratch using AFM diamond tip. As aluminum film is a good mask for etching silicon, high aspect ratio structures were finally fabricated by RIE process. The fabricated structures were studied by SEM, which shows that the grooves are about 400 nm in width and 5 microm in depth. To obtain sub-micron scale groove structures on the aluminum film, experiments of nanomachining on aluminum films under various machining conditions were conducted. The depths of the grooves fabricated using different scratch loads were also studied by the AFM. The result shows that the material properties of the film/substrate are elastic-plastic following nearly a bilinear law with isotropic strain hardening. Combined AFM nanomachining and RIE process provides a relative lower cost nano fabrication technique than traditional e-beam lithography, and it has a good prospect in nano imprint template fabrication.     

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.     

Fabrication of ferromagnetic nanoconstriction using atomic force microscopy nanoscratching

Nanolithography used in conjunction with atomic force microscopy (AFM) has attracted considerable attention as a technique for fabricating nanoscale structures. To obtain nanostructures and devices, AFM nanoscratching was performed on a photoresist and on NiFe at various values of the applied force, scan speed, and number of scan cycles. The scratching process was carried out using a diamond-coated tip on NiFe and a Si tip on the photoresist. By conducting scratching processes on NiFe and on the photoresist, we investigated the dependence of the size of the scratched part on the scratching parameters. These results show that the width and depth of the scratched part increase as the applied force and number of scan cycles increase, but not as the scan speed increases. This means that it is possible to control the size of the scratched parts by adjusting the applied force and number of scan cycles. AFM nanoscratching was then used to directly fabricate a nanoconstricted area with a width of 139 nm and a cross-sectional area of less than 300 nm2 was fabricated.     

纳米测量及纳米样板

介绍了纳米测量系统的组成以及纳米样板的研究现状．提出了两种制备纳米结构样板的方法：Si基底上的原子力显微镜(AFM)探针诱导阳极氧化工艺和Au膜上的AFM探针机械划刻工艺．最后对Si基底上制备的纳米结构样板进行了精度分析．     

Dip-pen lithography using pens of different thicknesses

A laboratory method to produce AFM tips of different sizes has been developed based on laser irradiation of the commercial silicon nitride tips. A few shots of 60 mJ at 355 nm were found adequate to induce the desired bluntness from 40 nm to 500 nm in a controlled way. Dip-pen nanolithography (DPN) has been performed with the blunt tips using a colloidal ink consisting of Pd nanocrystals coated with polyvinyl pyrrolidone. The line patterns drawn bear a direct relation with the tip morphology, wider the tip, broader are the patterns, in general. The rate of deposition also increases with the tip dimension, but is not as much proportional for larger tips. The study highlights the potential ability of DPN in integrating nano and microelectronics.     

Fabrication of nanostructure on a polymer film using atomic force microscope

SPM based lithographic techniques have been developed to pattern various substrates such as metals, semiconductors, and organic/polymer films due to its simplicity and high spatial precision nanostructure. Fabrication of nanostructure using polymeric materials is a key technique for the development of nanodevices. Here, we report the fabrication of nanostructures from polyacrylicacid (PAA) and polymethacrylicacid (PMAA) film on a silicon substrate using atomic force microscope (AFM). The formation of the nanopattern from the polymer film was studied using electrostatic nanolithography and the optimization of the conditions for nanopatterning of the polymer film was investigated with respect to the applied potential and translational speed of the AFM tip. The nanostructure of size 28 nm was created using the biased AFM tip on the PMAA film coated on Si(100) substrate and found that this method is a direct and reliable method to produce uniform nanostructures on a polymer film.     

Multifunctional Boron‐Doped Diamond Colloidal AFM Probes

Scanning probe microscopy techniques providing information on conductivity, chemical fluxes, and interfacial reactivity synchronized with topographical information have gained importance within the last decades. Herein, a novel colloidal atomic force microscopy (AFM) probe is presented using a spherical boron‐doped diamond (BDD) electrode attached and electrically connected to a modified silicon nitride cantilever. These conductive spherical BDD–AFM probes allow for electrochemical force spectroscopy. The physical robustness of these bifunctional probes, and the excellent electrochemical properties of BDD renders this concept a unique multifunctional tool for a wide variety of scanning probe studies including conductive AFM, hybrid atomic force–scanning electrochemical microscopy, and tip‐integrated chem/bio sensing.     

Removing material using atomic force microscopy with single- and multiple-tip sources

Atomic force microscopy (AFM) has been an effective material removing tool for fabricating various nanostructures because of its sub-nanometer precision and simplicity in operation. AFM material removing techniques have evolved from a solely mechanical process to one in which the tip can be loaded by additional energy sources, such as thermal, electric, or chemical, to enhance its fabrication abilities. In this paper, these material removing techniques are reviewed with an emphasis on their capabilities and recent progress. The recent hardware and software developments are first presented to provide a general view on the current status of the technology to be assessed. Following an overview of the feasibility and effectiveness of using mechanical scratching for removing various types of soft and hard materials, the processes of a wide range of approaches using multiple tip sources are then assessed with a focus on their principles, versatilities, and potentials for future applications.     

Plastic tip arrays for force spectroscopy

The mechanical stability and viability of molecules investigated with the atomic force microscope (AFM) continue to be limiting factors in the duration of force spectroscopy measurements. In an effort to circumvent this problem, we have fabricated an all-plastic array of over 30 000 tips with dimensions similar to common AFM probes using silicon micromolding techniques. This approach enables rapid fabrication of tip arrays with improved properties, as compared to tip arrays made entirely of silicon.     

硅表面十六烯薄膜的制备与表征

利用机械与化学结合的方法实现了硅基底上的可控自组装（“割草种花”思想）,为纳米尺度结构的构筑提供了一定的实验基础．基于金刚石刀具切削的自组装加工技术,在氢终止的硅表面上制备了十六烯自纽装单分子膜,并利用原子力显微镜（AFM）和X射线光电子能谱（XPS）对自组装膜进行了检测和表征,证明这种方法能够方便快捷地实现硅基底上的可控自组装;并用AFM检测了十六烯薄膜的黏着力,分析了可能导致其变化的原因,根据黏着力的变化也说明切削区域生成了自组装膜。