石英湿法腐蚀及侧壁晶棱修平工艺研究

以石英陀螺的微结构为研究对象,对石英的湿法腐蚀规律进行研究.选用500 μn厚Z切向石英片,蒸镀10 nm厚Cr膜和200 nm厚金膜作为掩模层,选用40%氢氟酸和40%氟化铵的1:1混合溶液作为腐蚀液.通过在不同温度下的腐蚀试验,表明腐蚀速率随温度增加而增大,温度过低腐蚀过慢影响腐蚀效率,温度过高使石英侧壁表面粗糙度增加.经过试验摸索,在70℃下腐蚀,可获得表面质量较好的石英微结构.石英在湿法腐蚀中结构侧壁会产生两级晶棱,根据侧壁主要晶面的腐蚀速率,计算出修平侧壁两级晶棱所需时间分别为8h和27h,经过试验验证,在预计时间内,石英侧壁晶棱基本修平.     

中国微米纳米-用于单电子自旋探测微悬臂梁的制作及端头磁颗粒设计

提出一种用于单电子自旋探测微悬臂梁的制作方法.采用顶层Si厚度为1μm的SOI硅片,在器件层刻蚀出悬臂梁图形后,利用热氧化将Si梁减薄至0.5μm,同时生成SiO2保护层.在KOH溶液进行体硅刻蚀过程中,以黑蜡和SiO2保护层作为正面保护,之后用溶液置换方法完成埋氧层去除及悬臂梁清洗过程.悬臂梁尺寸为465 μm×10 μm×0.5μm,室温真空中Q值为23 000,在低温环境中可以满足单电子自旋探测要求.分析比较了球体、圆锥体、圆柱体三种磁针尖磁场梯度分布,为磁针尖结构设计提供了依据.     

纳米级针尖制备控制系统设计与实现

制约扫描隧道显微镜分辨率的一个关键因素是其使用的针尖不够尖锐,如何制备出更加尖锐的针尖是当前扫面电镜分辨率突破的一个重要方面。在传统的制备工艺基础上,一种基于化学刻蚀和场致刻蚀的工艺流程可是实现制备纳米级针尖。本文介绍了该针尖的制备控制系统的设计与实现。该针尖的制备有其特殊性,据此开发了对应的控制系统,包括高压电源、控制箱、控制卡、相机等及对应的上位机控制程序,经实践验证,能够实现对超级针制备的工艺控制及数据记录。     

车身产品设计中的多层次尺寸链构建

尺寸偏差是影响汽车车身装配性能的一个主要因素,为了控制尺寸偏差,必须构建尺寸链模型以分析尺寸之间的相互复杂关系.以汽车车身设计为研究对象,分析了汽车车身装配的多层次、多等级特性;应用车身设计中的基准点系统和功能尺寸系统建立一种多级尺寸链模型,包括整车级、总成级、分总成级和零件级尺寸链.实例结构表明,所建立的多级装配尺寸链模型能使车身装配中的尺寸关系层次清晰化,并能对尺寸关系进行优化,使极为烦琐复杂的车身尺寸分析、偏差设计能有条不紊地逐步进行,为车身设计与制造改善找到了一条切实可行的路径.     

采用数码相机的图像测量方法研究

针对被测工件精确尺寸的要求，将数码相机用于尺寸的测量，采用了新颖的基于B样条算法进行边缘的定位，通过对实际工件进行测量得到了亚像素级的测量尺寸。试验结果反映了该方法的有效性。     

针尖对麦芒SONYVAIOZ VS ThinkPad X300

在ThinkPad大张旗鼓推出一代的X系列机型X300之后，SONY也推出了全新的VAIO Z系列，两者都是超轻薄机型的翘楚，也是商务机型的巅峰之作，同时更是大家目光聚集所在。相近的定位与售价，让不少用户在它们中间徘徊不定，在针尖与麦芒的对决中，孰优孰劣？     

肼对硅片的各向异性腐蚀技术研究

采用肼水溶液在各种条件下对硅片进行腐蚀 ,通过分析与腐蚀速率有关的因素 ,即改变腐蚀溶液温度和肼的质量分数 ,来提高腐蚀速率。整个实验过程实质就是寻求最佳腐蚀工艺条件 ,从而提高硅片的表面质量。     

铜缓蚀剂的筛选研究：MEC—12A多功能微机电化学分析仪的应用

缓蚀剂的筛选评定通常采用失重法,但因介质对铜的腐蚀较小,因而失重法的测量误差大,而利用电化学分析仪在一定的介质中对腐蚀下来的铜离子进行测定,能获得较满意的结果。本文采用MEC—12A多功能微机电化学分析仪与APPLE—Ⅱ型微型计算机配套使用,在专用软件控制下,利用方波技术进行铜离子测定,同时控制对铜缓蚀的影响因素,如pH值和缓蚀剂的浓度。根据溶液中铜离子的多少,就可判断铜缓蚀的     

基于虚拟弹簧模型的柔性针穿刺仿真研究

在分析柔性针受力和挠曲的基础上,建立二维空间上柔性针穿刺软组织的虚拟弹簧模型,得到针体和针尖轨迹的数学模型。使用Matlab工具软件对针尖轨迹在不同情况下进行仿真。仿真实验结果表明,柔性针弹性变形量对针尖走向影响较小,影响针尖走向的主要因素是纵向控制坐标和针座与水平线初始夹角,且两者的叠加效应最终影响柔性针走向,可以为机器人辅助针穿刺操控提供理论基础,结合软组织变形研究,能够实现柔性针穿刺的轨迹规划和避障运动。     

用于承载铷原子钟滤光泡的高品质微腔体制备

在芯片级铷原子钟中,需要微腔体来承载Rb—87滤光泡,为此,提出了一种用于制作高品质微腔体的新技术。为了获得光滑的腔体侧面和避免腐蚀过程中凸角处产生削角现象,研究中采用了超声腐蚀技术和凸角补偿技术。首先,分别在纯KOH溶液,并结合搅拌和超声等方法,对(100)硅片进行湿法腐蚀,并运用激光共聚焦扫描显微镜对腐蚀后的{111}表面进行粗糙度测量,表明运用超声腐蚀技术可以获得光滑的{111}腔体侧面。在此基础上,引入条形掩模凸角补偿方法进行微腔体腐蚀。实验结果表明:在80℃、质量分数为30%KOH、超声频率和功率分别为59 kHz和160 W的溶液中腐蚀,其{111}腐蚀表面粗糙度为0.117μm,同时条形的长度取1200μm时,可以获得平滑规整的微腔体。     

金属管道缺陷的微波检测

本文提出了一种用微波来检测金属管道裂纹、裂缝和表面金属异物等缺陷的一种新方法。文中详细介绍了微波检测金属管道裂纹、裂缝的原理和特征信号的提取方法，并用实验验证了该方法的正确性。     

一种三端式磁通门传感器激磁电路设计

磁通门传感器是目前微弱磁场检测中较为理想的测试元件,具有高灵敏度、高精度和良好的稳定性等优点;在分析了三端式磁通门传感器的数学模型的基础上,介绍了其工作原理,即需要激励源、传感器和检测电路共同作用才可以构成完整的测量系统;同时,设计了一种三端式磁通门传感器的激磁电路,其激励电压幅值为5V,频率为5kHz;结果表明,该信号频率和幅值比较稳定,可以作为磁通门传感器的激磁信号。     

Microfabrication of Pt-tip microelectrodes

This paper describes the realization of Pt-tip microelectrodes by using microfabrication technology. The total height of these microelectrodes is 47 μm, of which the upper 20 or 2 μm, respectively, are exposed Pt tips with a curvature of 0.5 μm. In order to verify the tip opening, an electrochemical plating of thin-film Pt was used. This improves the visualisation of the tips in an SEM and allows us to ascertain the absence of any residual layer. The manufacturing process was assessed by SEM imaging and, in the case of large Pt-tip electrodes, also by an electrochemical evaluation.     

Silicon microneedle array with biodegradable tips for transdermal drug delivery

This paper presents the fabrication process, characterization results and basic functionality of silicon microneedle array with biodegradable tips for transdermal drug delivery. In order to avoid the main problems related to silicon microneedles; the breaking of the top part of the needles inside the skin, a simple solution can be the fabrication of microneedle array with biodegradable tips. A silicon microneedle array was fabricated by deep reactive ion etching (RIE), using the photoresist reflow effect and RIE notching effect. The biodegradable tips were successfully realized using the electrochemical anodization process that selectively generated porous silicon only on the top part of the skin. The porous tips can be degraded within a few weeks if some of them are broken inside the skin during the insertion and release process. The paper presents also the results of in vitro release of calcein with animal skins using a microneedle array with biodegradable tips. Compared to the transdermal drug delivery without microneedle enhancer, the microneedle array had presented significant enhancement of drug release.     

磷酸中铜阳极电流振荡的互同步

物理系统振荡同步的成功实例已经有很多,但电化学系统振荡同步的实例还不多见.为了将用于物理系统振荡同步的方法应用于电化学系统,探索电化学振荡同步的新方法,以铜阳极在磷酸中的电流振荡为研究对象,以自制的电化学联机装置为工具,以铜阳极的电极电位为控制变量,用比例耦合同步方法研究2个独立电解池中铜阳极电流振荡的同步行为.本文的同步方法将比例调节和耦合方法结合起来,是2个电极电流振荡同步的有效算法.比例耦合同步方法的比例系数K为正值时,产生互同步效果;为负数时,产生反相同步效果.当两电极的振荡波形相同时,互同步的效果好;否则,效果差.在能发生电流振荡的电势范围内,铜在磷酸中阳极溶解的电极电位与电极电流之间成反比关系.根据这个反比关系,定性解释了本文方法实现互同步和反相同步的机理.2个互同步的电极电流之差很接近于零,但因为2个铜阳极的表面粗糙度很难完全相同,导致真实的电化学反应面积也很难完全相同,总有余差存在.根据比例调节的特点,用反证法证明余差的存在是本文的互同步方法能够成功实现的前提条件.最后,本文对互同步算法指出了改进的方向.     

Electrochemical post-processing of LIGA structures

The Louisiana State University (LSU) Microsystems Engineering Team (μSET) is developing techniques for producing microstructures with predictable 3-D geometry. One approach is based on controlled anodic dissolution of electroplated structures to obtain desired shapes. A finite element model was developed to predict the resulting shapes. As a demonstration of the shaping process, development of LIGA-based scanning probe microscope tips was investigated. An array of micro-posts 1.8 micrometers in diameter and 12 micrometers high was produced using x-ray lithography and subsequent electrodeposition. The posts were sharpened electrochemically. Other geometries are being investigated.     

Electrochemical post-processing of LIGA structures

 The Louisiana State University (LSU) Microsystems Engineering Team (μSET) is developing techniques for producing microstructures with predictable 3-D geometry. One approach is based on controlled anodic dissolution of electroplated structures to obtain desired shapes. A finite element model was developed to predict the resulting shapes. As a demonstration of the shaping process, development of LIGA-based scanning probe microscope tips was investigated. An array of micro-posts 1.8 micrometers in diameter and 12 micrometers high was produced using x-ray lithography and subsequent electrodeposition. The posts were sharpened electrochemically. Other geometries are being investigated. Received: 30 October 1995/Accepted: 18 December 1995     

Flexible tooling for localized electrochemical deposition with wire-electrodischarge grinding

This paper describes the application of electrodes with varying diameters made by wire-electrodischarge grinding (WEDG) in the localized electrochemical deposition (LECD) of nickel micro-columns. WEDG has been widely used in the fabrication of extremely fine cylindrical pins mainly used as tool electrodes for micro-electrodischarge machining of fine holes or as contoured cores in the electroforming of micropipes. Similar to electrolysis, LECD is a new deposition technique which uses conductive tips as anode electrodes to focus the electric field that drives the process such that deposition is largely localized on the smooth cathode surface beneath the anode tip. The degree of localization depends mainly on the anode diameter, the anode-to-cathode separation, the insulation or non-insulation of the anode, and the computer-controlled motion of the anode tip during the deposition process. Considering the parameter of anode tip diameter alone, the ability to fabricate tips of differing diameters will allow a wide range in resolution of structures deposited via LECD. WEDG provides this flexible tooling for LECD at the micro to meso-scale. Experiments were carried out on a custom-built LECD rig on which nickel columns were deposited from a nickel sulphamate plating solution, using stationary and rotating WEDG-ed tips with diameters ranging from 25 to 120 m. Aspect ratios of up to 9:1 were achieved and deposited column diameters were found to display a linear relationship with the WEDG-ed anode tip diameters. Electrode rotation was also found to improve column cross-sectional roundness and overall dimensional control for fabrication with LECD.This work was sponsored by Nanyang Technological University, Singapore, via Applied Research Fund RG 30/99.     

Finite Volume model for diffusion- and activation-controlled pitting corrosion of stainless steel

Steel corrosion plays an adversary, but central role in different technological fields. Reasonable modeling of corrosion calls for a profound theoretical study of the underlying mechanisms. The present paper is concerned with mathematical modeling of (localized) pitting corrosion: We derive the mass conservation law of a dissolving body hosting a metal/solution interface which separates the solid metal electrode from the liquid electrolyte, and we complement the mass balance law by a thermally activated, potential-dependent electrochemical kinetics law for the dissolution reaction and by Fick’s law for ionic transport in the electrolyte solution. As long as the electrolyte solution adjacent to the electrode boundary does not reach its saturation level, the Arrhenius-type dissolution kinetics law governs the dissolution rate, and Fick’s law governs solely the concentration distribution in the electrolyte solution (activation-controlled corrosion mechanism). However, once the saturation level is reached at the electrode boundary, the pit depth evolution is governed by the diffusion of ions from the electrode boundary into the electrolyte-filled pit (diffusion-controlled corrosion mechanism). Corresponding mathematical solutions (time-dependent fields of concentrations) are obtained by means of the Finite Volume Method. For experimentally supported model input values (concerning dissolution activity, corrosion potential, transfer coefficient, metal charge number, ionic saturation concentration, and solid metal concentration), the influence of the overpotential on the corrosion characteristics (pit depth and shape evolution, current density, ionic concentrations in electrolyte) is shown by means of 1D and 2D simulations.     

Electrochemical machining: new possibilities for micromachining

A better understanding of high rate anodic dissolution processes is urgently required for electrochemical micromachining (EMM) to become a widely employed manufacturing process in the electronic and precision manufacturing industries particularly in the micromanufacturing domain. A successful attempt has been made to develop an EMM setup for carrying out in depth independent research for achieving satisfactory control of electrochemical machining process parameters to meet the micromachining requirements. The developed EMM setup mainly consists of various sub-components and systems, e.g., mechanical machining unit, microtooling system, electrical power and controlling system and controlled electrolyte flow system, etc. All these system components are integrated in such a way that the developed EMM system setup will be capable of performing basic and fundamental research in the area of EMM fulfilling the requirements of micromachining objectives.