“超快激光加工与微纳制造”专题前言

<正>激光制造技术历经多年的研究发展,涵盖了以激光表面工程、激光焊接、激光切割、激光制孔、激光标记、激光增材制造等为代表的宏观制造技术,以激光微焊接、激光精密切割、激光精密钻孔、激光烧蚀等为代表的激光微加工技术,和以飞秒激光直写、双光子聚合、干涉光刻、接触离子透镜序列、激光诱导表面纳米结构和纳米颗粒激光制备等为代表     

适用于微加工工艺的纳米多孔铜制备方法

主要研究了一种适用于微加工工艺的纳米多孔铜(NPC)制备方法。采用酸性柠檬酸铜锌电镀体系制备出Cu68Zn32前驱合金,通过改变前驱合金在盐酸中去合金的时间可以对NPC的微观形貌及孔径分布进行有效控制。研究结果表明,在0.05 mol/L的盐酸中腐蚀6 h后制备的NPC孔径为80~120 nm,而系带尺寸为20~40 nm,利用BET法测得其比表面积为8.12 m2/g。另外,应用微加工工艺制备出边长为50μm方形微阵列,验证了该NPC制备工艺与微加工工艺有较好的兼容性,为NPC的图形化与集成制造提供一种有效的工艺方案。     

基于硅模具制作的纳米裂纹及应变传感器

纳米裂纹制造技术作为一种非传统的纳米加工技术被应用于纳米线条、纳流控芯片和传感器等众多研究领域,然而纳米裂纹生成的随机性及其图案的不确定性限制了该项技术的发展.利用硅模具以及二次倒模工艺,在聚二甲基硅氧烷(PDMS)基底表面制作相互平行且分布均匀的金纳米裂纹.硅模具上带有利用硅各向异性腐蚀工艺加工出的V型沟槽结构,通过...     

加工对称梁岛结构的微机械加工新技术

本文报道了一种用无掩模腐蚀技术加工对称梁岛结构的微机械加工技术。根据硅台阶在ＫＯＨ无掩模腐下形状和尺寸的变化规律，可以设计制造出一般掩模腐蚀难以形成的微机械对称当今岛结构。由于该技术工艺简单，易于控制，为制作对称梁岛结构的硅 速度传感器提供了新的加工手段。     

三维金属MEMS器件电化学制造技术

EFAB技术是微加工领域一项重大的突破，开辟了MEMS金属器件加工的新天地，与其他微加工技术相比，EFAB技术的主要优点是：可实现MEMS中复杂三维金属微结构器件快速、自动化、批量制造。基于快速原型思想，EFAB利用实时掩模技术将金属材料层层叠加起来，可以加工任意形状的金属三维微结构。介绍了EFAB技术原理，并对其加工设备、分层技术、实时掩模、过程监控等关键技术进行了剖析，最后给出了应用实例。     

新纳米晶体管展现强量子限制效应

美国得克萨斯大学的一个研究小组用非常细的纳米线制造出一种晶体管,表现出明显的量子限制效应,纳米线的直径越小,电流越强。该技术有望在生物感测、集成电路缩微制造方面发挥重要作用。相关研究发表在最近出版的《纳米快报》上。实验中,他们用平版印刷技术制造了一种直径仅有3纳米到5纳米的硅纳米     

飞秒激光在6H-SiC表面诱导偏振依赖纳米结构特性研究

激光诱导偏振依赖纳米结构是一种有效实现纳米图案化的技术,并且一直备受研究者的青睐。利用飞秒激光微加工技术,对6H-SiC晶体表面激光诱导偏振依赖纳米结构特性进行了研究。通过改变入射激光加工偏振态和延迟时间样品表面诱导产生了直径约为150 nm的球形纳米颗粒、椭圆形纳米颗粒和空间周期约为150 nm的高空间频率表面条纹结构。实验结果表明,入射激光偏振特性会直接影响诱导产生的微结构形貌,并且优先入射的飞秒激光对最终产生的表面微结构形貌有决定性作用。初步探讨了偏振依赖纳米结构形成的物理机制,表面等离激元(surface plasmon polariton, SPP)在表面微纳米结构的产生过程中扮演着重要角色,研究结果对激光诱导表面周期结构(laser-induced periodic surface structures, LIPSS)可控制备具有重要意义。     

紫外-可见光还原控制银纳米周期结构与形貌及其在表面增强拉曼散射中的应用

光还原特别是激光还原金属离子制备纳米结构作为一种化学成分纯净和工艺可控性高的微纳制造手段,已经得到了广泛的研究与应用。目前,该方法加工出的金属结构已应用于光谱检测、生物荧光成像、三维微纳结构制造等领域。针对当前基于双(多)光子吸收效应直写技术无法解决的加工效率低等问题,采用紫外纳秒激光双光束干涉法,提出了一步原位光还原银离子的制造方法。结合紫外和可见光辐照还原银离子,成功制备出大面积具有不同表面形貌的纳米级周期的光栅结构。详细讨论了激光还原时间、银离子浓度、不同波长光辐照等条件对光还原的影响,对双束光干涉以及光还原机制进行了分析。另一方面,银离子还原后形成的结构是由大量的尺寸为几十纳米的颗粒构成,排列紧密,因而具有显著的表面增强拉曼效应。对萘普生分子进行检测后,证实了该纳米结构具有较优的表面增强效果。     

纳米电子学

纳米电子学是纳米技术的重要科学基础,纳米电子学将成为21世纪信息时代的科学核心,将使未来社会产生重大变革。本文介绍了纳米电子学的基本概念、纳米电子学的产生、纳米电子学的研究内容、纳米器件的基本结构及工作机理、纳米结构的微加工技术、纳米结构的检测与表征、纳米电子学的应用及发展对策。     

利用扫描隧道显微镜构建纳米结构

通过对在Si(111)-7×7表面上生长的Pb岛施加脉冲偏压,Pb岛受到触发而自发再生长.通过调节操纵参数(如脉冲电压的大小和时间),岛的高度及形状可以较精确地控制.用这种方法,我们可以制造出一些特定形状的纳米结构,例如中空和半中空的纳米阱等,还可以在更大尺度(微米)上进一步构建由这些纳米结构单元构成的图案.在纳米结构的构建过程中,还观察到了量子效应对薄膜生长的影响.     

高能电子束曝光技术研究

介绍了将商用透射电镜JEM—2000EX改造为高能电子束曝光系统的研制工作，在现阶段研制工作的基础上进行了曝光实验。结果表明，利用此高能电子束曝光系统可以制备出纳米线条，并且能够制备出具有高深宽比的微细结构，从而为微小器件的加工提供了新的方法。     

用于高效太阳电池的硅基微纳结构及制备

介绍了用于高效太阳电池的几种硅基微纳结构的最新研究进展,重点介绍了几种硅基微纳结构的制备方法,如阳极腐蚀制备多孔硅、各向异性制绒以及气液固(VLS)生长纳米线等,并对各种方法的特点作了分析比较,指出了各种方法存在的问题。最后对今后研究的方向做了展望,由于太阳电池在性能提高以及产业应用方面的需求,未来用于高效太阳电池的硅基微纳结构仍是研究的热点之一。进一步提升其对太阳电池效率的优化能力将是研究的重要关注点,而其制备技术也将向着低成本、大规模及可控制的方向发展。     

石墨烯微纳结构加工技术的研究进展

简单介绍了石墨烯独特的光电子性质,说明实现其在光电子器件中应用的有效方法是进行微纳加工。接下来对主要的石墨烯微纳加工技术——掩膜光刻、转移压印以及激光直写和干涉进行详细阐述,通过实例对每种加工技术的关键步骤和特点进行说明,并分析比较了不同加工技术的优缺点。然后对近期出现的转移压印辅助光刻和飞秒直写辅助转移压印技术的加工流程进行详细介绍,阐述将两种加工技术相结合应用于石墨烯微纳结构加工的优势。最后,简单展望了石墨烯微纳加工未来的发展趋势,指出需进一步研究的问题,对如何更好地实现石墨烯微纳结构的加工提出一些建议。     

Micro and nano structures of carbonised polymer through pyrolytic transformation from polymer structures

Micro and nano structures of carbonised polymers resulting from the pyrolytic transformation of polymer structures are presented. Polymers have become increasingly popular as materials for micro/nano electromechanical systems (MEMS/NEMS), especially for chemical or biological application. Focus is on the transformation of polymer structures into carbonised structures using a pyrolysis process. Combination of this pyrolysis process with conventional MEMS/NEMS fabrication technology could provide various fine structures of carbonised polymer. Carbonised polymers have advantages over conventional carbon materials, with respect to compatibility with MEMS, because they can be transformed directly from a polymer structure. Three-dimensional micro and nano free-standing structures of carbonised polymer as typical MEMS/NEMS structures are reported. Micro molding process is used to demonstrate a unique polymer structure to be pyrolysed. Furthermore, EB lithography technology is employed for the patterning of polymers in addition to UV photolithography which is used by previous researches. A 100 nm wide bridge structure is designed as nano structures. In addition, the presented structures of carbonised polymer are expected to be applied to micro and nano functional devices such as electrochemical sensors by making the best use of their carbon-like features     

基于碳纳米管的微纳机电器件应用研究

综述了近年来碳纳米管在微纳传感器、纳米发电机、纳米执行器、纳米电子器件、纳米收音机与薄膜扬声器等方面取得的瞩目成果及典型应用,介绍了基于碳纳米管的微纳机电器件的制造工艺、器件性能及其研究进展,指出了碳纳米管基微纳机电器件在多元化发展、工艺多样化、材料复合化、产业化工程等方面的发展趋势。     

Conductivity of SU‐8 Thin Films through Atomic Force Microscopy Nano‐Patterning

Processing flexibility and good mechanical properties are the two major reasons for SU‐8 extensive applicability in the micro‐fabrication of devices. In order to expand its usability down to the nanoscale, conductivity of ultra‐thin SU‐8 layers as well as its patterning by AFM are explored. By performing local electrical measurements outstanding insulating properties and a dielectric strength 100 times larger than that of SiO₂ are shown. It is also demonstrated that the resist can be nano‐patterned using AFM, obtaining minimum dimensions below 40nm and that it can be combined with parallel lithographic methods like UV‐lithography. The concurrence of excellent insulating properties and nanometer‐scale patternability enables a valuable new approach for the fabrication of nanodevices. As a proof of principle, nano‐electrode arrays for electrochemical measurements which show radial diffusion and no overlap between different diffusion layers are fabricated. This indicates the potential of the developed technique for the nanofabrication of devices.     

Fabrication of micro/nano fluidic system combining hybrid mask-mould lithography with thermal bonding

Polymer-based micro/nano fluidic system is becoming indispensable for biological applications as well as physical chemistry research. In this article, we demonstrate a novel fabrication process for nano fluidic system based on hybrid mask-mould (HMM) lithography and thermal bonding using SU-8. With the HMM lithography, the protrusions of channels and reservoir patterns can be replicated in one step. Bonding process conditions are flexible and easily controllable with the use of PET substrate and the thin adhesive layer. Surface textures were found to be essential to the bonding strength and channel profile control. The fabricated fluidic system was characterized using spontaneous capillary filling with dyed water, demonstrating good quality of sealing.     

Fabrication of a 3D stamp with the micro- and nano-scale patterns through combined NIL and optical lithography processes

Nanoimprint lithography is in the spotlight of the nano technology field for its ability to produce large area patterning [1], [2], [4]. This kind of lithography is also able to fabricate three-dimensional functional structures all at once. In order to fabricate three-dimensional structures for an entire wafer, simple fabrication of three-dimensional large area stamp that combines micro- and nano-scale patterns is required. This paper proposes, the fabrication process of three-dimensional large area stamp that incorporates both micro- and nano-scale pattern. The three-dimensional stamp, which accounts for areas that range from 70nm to 3um, is fabricated on a Si substrate using nanoimprint lithography and optical lithography.     

Nanofabrication of gallium nitride photonic crystal light-emitting diodes

We describe a comparison of nanofabrication technologies for the fabrication of 2D photonic crystal structures on GaN/InGaN blue LEDs. Such devices exhibit enhanced brightness and the possibility of controlling the angular emission profile of emitted light. This paper describes three nano lithography techniques for patterning photonic crystal structures on the emitting faces of LEDs: direct-write electron beam lithography, hard stamp nanoimprint lithography and soft-stamp nanoimprint lithography with disposable embossing masters. In each case we describe variations on the technique as well as its advantages and disadvantages. Complete process details have been given for all three techniques. In addition, we show how high performance GaN dry etch techniques, coupled with optical process monitoring can transfer resist patterns into underlying GaN material with high fidelity.     

A novel loading and demoulding process control in UV nanoimprint lithography

In UV nanoimprint lithography (NIL) with elastic mould, a novel multi-step loading and demoulding process, called distortion reduction by pressure releasing (DRPR) and two-step curing method for demoulding, is developed. This novel imprint process is continuous, the pressure releasing method, used to optimize the loading process, can reduce the distortions of imprint mould and wafer stage, while obtain better cavity filling and thin and uniform residual layer; through two-step curing method instead of traditional simple demoulding, the curing degree of resist can be controlled, which is helpful to decrease the demoulding force and avoid residual layer pulled-up while ensure replicated protrusions not collapse. It is a novel and robust process with high fidelity of pattern replication in micro/nano structures fabrication, and the replication error caused by distortions and “blind” demoulding can be reduced effectively.