星载自适应光学系统新型可变形反射镜的研究

给出基于硅微加工技术的一种新型可变形反射镜的设计和加工方法。从静电驱动的角度阐述此种反射镜的结构设计原理,并对具体加工中的腐蚀和键合工艺进行了详细讨论。成功制造出有效反射面积为30 mm×30 mm,拥有49个静电驱动单元的可变形反射镜。     

基于光致抗蚀干膜的掩膜制备及其应用研究

在传统工艺流程中,必须先将干膜贴于工件表面,然后进行光刻,但干膜不可重复使用。现提出一种新型干膜光刻工艺流程,在干膜贴于工件表面之前,先对干膜单独进行光刻试验研究。基于该新型工艺流程,研究了杜邦干膜GPM220的曝光及显影特性。经过对曝光量（曝光时间）及显影时间的参数优化,最终在干膜上获得了平均直径为99.7μm的通孔阵列,并将其作为掩膜应用于微细电解加工,通过选择合理的加工参数,在工件表面获得了平均直径为125μm、平均深度为10μm的微坑阵列。电解实验后的干膜易与工件分离,可实现重复使用,提高了干膜的利用率。     

Modeling and fabrication of microhole by electrochemical micromachining using retracted tip tool

Accurate microhole is a key feature for many kinds of micro parts widely used in diverse industries. But machining of microhole using traditional processes faces great challenges due to the thermal-mechanical effects. Electrochemical micromachining (EMM) is a potential technique to meet the requirement of high-quality microhole fabrication. However, the currently-used microtools suffer from some drawbacks such as stray dissolution, bell-mouth entrance and excess radial overcut. To overcome these limitations, a novel microtool with retracted tip structure is proposed in this work. A mathematical model has been developed to investigate the effect of retracted tip depth on machining accuracy. And an empirical formula is obtained based on the model to predict the diameter of the generated microhole. Experimental verification is performed on a home-made EMM system and reveals good correlation with the theoretical predictions. Using this novel microtool with optimum retracted tip depth, high-quality microholes have been fabricated on aluminum and 304 stainless steel sheets.     

电流变技术在微型机械系统中的应用研究

介绍了电流变技术在微型机械系统中的应用，特别介绍了三通口微型电流变阀的结构特点，制造工艺，基本特性，并通过实验模型阐述了这种阀的可行性。     

Tool wear and form accuracy in ultrasonically machined microchannels

Quantifying wear on the basis of weight at micro levels may be erroneous. Moreover, information about wear distribution cannot be obtained on the basis of weight monitoring. Thus, quantification on the basis of linear measurements is an effective solution at micro levels. This paper presents a mathematical model for quantifying wear measured in two dimensions and subsequently converting it to a three dimensional wear model. The efficacy of the model was verified through machining data from ultrasonic micromachining of glass with tungsten carbide tools. The tool wear values obtained for the model was then correlated with the form accuracy of the machined microchannel which were found reasonable. Further, the effects of different process parameters like abrasive concentration, power rating, abrasive size and workpiece feed were studied on the tool wear behaviour and presented vis-a-vis microchannel form accuracy. High power rating and high abrasive concentration resulted in more tool wear and increased form inaccuracy; coarse abrasives resulted in higher form inaccuracy. Longitudinal wear resulted in decreased microchannel depth while lateral wear led to tapered microchannel walls and edge rounding wear yielded rounded corners in the fabricated microchannels.     

Design of a Microfluidic System to Investigate the Mechanical Properties of Layer‐by‐Layer Fabricated Capsules

A microfluidic system was designed, fabricated and implemented to study the behavior of polyelectrolyte capsules flowing in microscale channels. The device contains microchannels that lead into constrictions intended to capture polyelectrolyte microcapsules which were fabricated with the well‐known layer‐by‐layer (LbL) assembly technique. The behavior of hollow capsules at the constrictions was visualized and the properties of the capsules were investigated before and after introduction into the device.

Time series of video frames showing capsules being compressed into a constriction.     

Preparation and characterization of ZnO microcantilever for nanoactuation

ABSTRACT: Zinc oxide [ZnO] thin films are deposited using a radiofrequency magnetron sputtering method under room temperature. Its crystalline quality, surface morphology, and composition purity are characterized by X-ray diffraction [XRD], atomic force microscopy [AFM], field-emission scanning electron microscopy [FE-SEM], and energy-dispersive X-ray spectroscopy [EDS]. XRD pattern of the ZnO thin film shows that it has a high c-axis-preferring orientation, which is confirmed by a FE-SEM cross-sectional image of the film. The EDS analysis indicates that only Zn and O elements are contained in the ZnO film. The AFM image shows that the film's surface is very smooth and dense, and the surface roughness is 5.899 nm. The microcantilever (Au/Ti/ZnO/Au/Ti/SiO2/Si) based on the ZnO thin film is fabricated by micromachining techniques. The dynamic characterizations of the cantilever using a laser Doppler vibrometer show that the amplitude of the cantilever tip is linear with the driving voltage, and the amplitude of this microcantilever's tip increased from 2.1 to 13.6 nm when the driving voltage increased from 0.05 to 0.3 Vrms. The calculated transverse piezoelectric constant d31 of the ZnO thin film is -3.27 pC/N. This d31 is high compared with other published results. This ZnO thin film will be used in smart slider in hard disk drives to do nanoactuation in the future.     

Porous silicon bulk micromachining for thermally isolated membrane formation

A novel low thermal budget technique is proposed for the preparation of thermally isolated silicon membranes. The selective formation of porous silicon in a p-type silicon wafer results in an undercut profile below the implanted n-type silicon regions. The sacrificial porous layer is subsequently removed in a dilute KOH solution. A non-stoichiometric LPCVD nitride layer combination forms the suspension of the single-crystalline silicon membranes. This technique eliminates the need for epitaxial substrates and backside alignment, and proves to be very efficient in the realization of a high-temperature micro-hotplate operating with minimum power consumption for the purpose of integrated gas sensors.     

中国微米纳米-基于低温共烧陶瓷的微机械差分电容式加速度计的研究

低温共烧陶瓷（LTCC）技术是实现电子设备小型化、高密度集成化的主流封装/组装集成技术,可适用于耐高温、耐受恶劣环境下的特性要求。本文报道了以LTCC为结构材料设计、制作的一种MEMS差分电容式加速度计。该器件的敏感质量、四根悬臂梁结构都内嵌于LTCC多层基板,质量块和上下盖板之间通过印刷电极组成差分电容对;高精度电容检测芯片表贴于LTCC基板表面,将差分电容信号转化为电压信号。论文讨论了微机械LTCC加速度计的设计与制备、检测电路和性能测试。LTCC的高密度多层布线减小了互连线的长度和相关耦合寄生电容;基于集成芯片的检测电路解决了分立式检测电路的引起噪声大、电路复杂等问题。测试结果表明：该加速度计结构灵敏度较高,小载荷情况下表现出良好的线性关系,灵敏度约为30.3mV/g。     

MEMS空间光调制器的研究现状与发展趋势

空间光调制器是自适应光学系统中用来实时校正波前畸变的关键器件,其发展水平能够反映整个自适应光学系统的水平。基于微电子机械系统(MEMS)技术的空间光调制器具有体积小、能耗低、驱动器单元密度高以及与集成电路工艺兼容性好等优点,而成为空间光调制器领域研究的热点。详细介绍了MEMS空间光调制器的研究现状和存在的主要问题,并分析了MEMS空间光调制器的未来发展趋势。