聚合物胶粘剂粘片FMEA研究

芯片的粘接质量直接决定了集成电路产品的可靠性和使用寿命,目前主流的芯片粘接工艺为聚合物粘接工艺。使用该工艺的产品覆盖了军民品各领域,但是随着微电子行业的迅速发展,以及产品使用环境的日益恶化,对于聚合物粘接的质量可靠性要求也变得日益严格,因此对聚合物粘接控制工艺开展研究,有助于聚合物粘接质量的提升。通过对聚合物胶粘剂粘片工序引入FMEA方法进了研究探讨,对于实际生产及芯片粘接能力的提升有着重要的指导意义。     

适用于ＴＥＭ原位表征的双温区密封腔芯片研制

基于透射电子显微镜的原位表征技术是研究低维电子材料的先进技术方法。虽然该技术已有许多发展,但在透射电子显微镜中原位观察化学气相生长过程一直存在困难,这其中一项重要挑战就是如何在电镜真空腔体中构建微区高压气氛反应环境。本文研制了一种适用于透射电子显微镜的双温区密封腔芯片,该芯片的两个加热区可模拟蒸发和生长条件,有助于实现在透射电镜中直接观察低维材料的生长及结构动态演化过程。本文还通过有限元方法仿真了芯片的温度分布、测试了芯片气密性,并装配到透射电子显微镜样品杆中进行验证。实验结果表明,该芯片可实现在透射电镜中可控加热并观察低维材料的结构演化,能有效拓展原位透射电子显微技术的应用范围。     

极限电流型氧传感器的特性研究

环境气氛条件对氧传感器的性能有直接的影响,本文对极限电流型氧传感器在常压常氧环境和高CO2环境下的输出特性进行了研究,同时根据传感器的前级信号放大电路对使用氧传感器时的取样电阻取值、预热时间进行了研究.     

水溶性光电聚合物及其生物传感器研究

由于聚合物通过单体集成系统响应外界环境的刺激,具有放大效应,因而采用新型水溶性光电聚合物研制的生物传感器灵敏度很高,此外还具有快速、简便、特异性强等优点.在痕量核酸分析时,不需要通过PCR放大,即可作为核酸分子诊断工具[1].利用聚合物与核酸氢键相互作用,Nilsson等提出了一种研究聚合物与核酸相互作用的新方法[2].该法可用于监测溶液中和芯片上的核酸杂交反应;可在室温条件下,5 min左右完成特定序列分析.简便、快速、成本低.此类聚合物除了具有优良的荧光特性外,这些聚阳离子和聚阴离子的电活性特性可用于检测或用作缠绕核酸的导线.     

一种改进的AD698电感传感器电路

提出了一种改进的AD698电感传感器测量电路,降低AD698芯片的工作功率,避免AD698芯片由于长时间工作使芯片过热,引起测量电路的温漂.介绍了AD698电感传感电路的工作原理,介绍了改进型电路的设计,对改进前和改进后的电路进行了测量实验,实验结果表明:改进后的AD698电感传感电路在长时间工作状态下几乎没有温度漂移.     

ETA10液氮冷却超级计算机系统

使用液氮温度下操作的ＣＭＯＳ电路技术开发了一种超级计算机。２０００个封闭电路芯片（每个芯片高达２０００个门）在低下９０Ｋ（大约是电路芯片速度的两倍）的温度下操作，内部自测试的广泛使用的器件和互连提供了从铸造的硅片到浸在液氮中的中央处理器产品的可测性，器件的封装与互连要特别注意材料的选择，以确保连接结构的可靠性，在器件与印制板一级已完成室低温循环研究，传热试验旨在证实在液氮－１２Ｗ／ｃｍ＾２的成核沸     

某种非金属材料粘接件的贮存性能预测分析

通过用聚氨酯胶粘剂对聚酯材料进行粘接后的加速老化试验和一年长贮试验,采用平均速率法和改进反应速率法,研究了该聚氨酯胶粘体的性能变化规律,建立了该胶粘剂在不同温度下的老化速率公式,分析了聚酯材料粘接件在25℃条件下的相对剩余强度,评估了该材料用聚氨酯胶粘剂粘接后的储存寿命,预测该种非金属粘接件其12年长期贮存后的性能可以满足使用要求。     

压阻式高温压力传感器温度补偿与信号调理设计与测试

设计制作了一种集成信号调理电路的高温压阻式压力传感器,包含倒装式的压敏敏片、无源电阻温度补偿电路和信号调理电路组成;压敏芯片的制作采用SOI材料和MEMS标准工艺,温度补偿和信号调理电路采用高温电子元件;试验表明,无源电阻温度补偿具有显著的效果;此外,采用了高温信号调理电路来提高传感器的输出灵敏度,通过温度补偿来降低输出灵敏度;与传统的经验算法相比,所提出的无源电阻温度补偿技术具有更小的温度漂移,在220℃条件下传感器输出灵敏度为4.93 mV/100 kPa,传感器灵敏度为总体测量精度为±2%FS;此外,由于柔性传感器的输出电压可调,因此不需要使用一般的电压转换器随动压力变送器,这大大降低了测试系统的成本,有望在恶劣环境下的压力测量中得到高度应用。     

黑白摄象机中的自动化电路

<正> 目前,国内外先进机型的黑白摄象机都设计有自动化电路,目的是扩大摄象机的使用范围。使摄象机不仅在标准状态(常温、标准照度)下能输出标准的全电视信号,而且使摄象机在温度大范围内(-10°～+50℃)变化、景物照度大范围内(低照度从0.5LUX～30,000LUX,一般照度从3～100,000LUX)变化的环境中长时间工作时,仍能输出稳定的全电视信号,从而保证摄象机在上述复杂环境条件下,仍有高质量的图象信号输出。下面,介绍笔者开发的几种实用的自动化电路。一、自动靶压控制电路这种电路是配合Vidicon管(硫化锑摄象管)的使     

一种具有双重输出功能的超声波测距系统

本文研究了以AT89C2051单片机为核心的超声波测距传感器的工作原理,系统组成,硬件电路和软件设计方法。创造性地引入了ISD1420语音芯片电路,与LED相结合,使系统同时具有数码显示和自动语音报数双重结果输出功能,适于在特殊环境下和特殊人群使用,更具有便捷性和新颖性。同时分析了温度补偿问题和盲区问题,提出了解决方法。     

Flip chip packaging for MEMS microphones

We have developed a microphone package using flip chip technology instead of chip and wire bonding to create smaller MEMS microphones. With this new packaging technology the transducer chip and an ASIC chip are flip chip bonded on a ceramic substrate. The package is sealed by a polymer foil laminated over the chips and by a metal layer. The sound port is on the bottom side in the ceramic substrate. In this paper the packaging technology is explained in detail and results of electro-acoustic characterization and reliability testing are presented. We will also explain the way which has led us from the packaging of Surface Acoustic Wave (SAW) components to the packaging of MEMS microphones.     

Figure-ground segregation using an analog VLSI chip

An analog, parallel, computational system, built on a single, power-lean, CMOS VLSI chip, that labels all points inside a possibly incomplete and noisy contour in real time is described. The circuit performs figure-ground segregation of a scene, labeling all the points inside a designated figure by one voltage and all other parts outside this object using a different voltage value. Its behavior is shown to be robust, since small breaks in the contour are automatically sealed, providing for figure-ground segregation in a noisy environment. The two major limitations of the current figure-ground chip are its limited capability for recognizing figures with large gaps in the contour and the constraint that the figure always has to be centered     

Multilayer patterning technique for micro- and nanofluidic chip fabrication

Polymer micro- and nanofluidic chips become increasingly significant for medical and biological applications. However, it is difficult to fabricate micro- and nanochannels integrately into a polymer substrate due to the reflow and insufficient flow of the polymer. In the present paper, micro- and nanochannels were hot embossed into a multilayer substrate by micromold and nanomold, respectively. To replicate high replication precision nanochannels without damaging the fabricated microchannels, the embossing parameters were optimized by Taguchi and analytic hierarchy process methods. The fabricated micro- and nanochannels were fully sealed at bonding parameters optimized according to the bonding rate of the chip. The fluorescence image indicates that there is no blocking or leakage over the entire micro- and nanochannels. With presented fabrication method, low-cost polymer micro- and nanostructures can be fabricated, which allows for commercial manufacturing of micro- and nanofluidic chips.     

A closed-loop mass flow controller based on static solid-state devices

A mass flow controller, based on an integrated flow sensor and a thermally actuated solid state regulator, is presented. The sensor is a miniaturized differential calorimeter obtained by postprocessing a silicon chip fabricated by a standard microelectronic process. The regulator consists in a microchannel etched into the surface of a silicon substrate and sealed with a glass plate, joined to the silicon die using anodic bonding. Flow regulation is achieved by varying the channel temperature by means of a chromium resistor. The two devices are connected in closed-loop through a low noise-low offset electronic circuit. Experimental data, demonstrating the effectiveness of the flow controller, are presented. Limitations of the proposed approach and possible improvements are discussed.     

Rubber-assisted embossing of polymer thin films using molds with through-thickness microchannels

A flexible microfluidic chip is difficult to fabricate using the standard hot embossing technology. In this study, rubber-assisted embossing of polymer thin films using molds with through-thickness microchannels was investigated. The polymer film was thermoformed into the microchannels by rubber as a soft counter-tool. Different processing conditions, as well as material selections, affecting the thickness uniformity and replicated depth were examined. Results indicated that smoother surfaces on the embossed articles were created, and the thickness uniformity and the depth of the embossed channel were significantly affected by the embossing temperature, the embossing pressure, and the rubber hardness. The embossed film was sealed on one side with a layer of transparent adhesive film to form closed microchannels, and desired 3-D flow characteristics were obtained with this flexible microfluidic chip.     

A device for skin moisture and environment humidity detection

Water content detection is important for our daily life. For environmental detection, the relative humidity is an index for comfortable living atmosphere. For skin health, the water content in stratum corneum is a parameter to diagnose the skin condition. This paper mainly describes a moisture sensor for determination of human skin moisture. The skin moisture sensor is based on the conventional humidity sensor structure (interdigital capacitance, IDC), and the moisture sensor is also sensitive to the environmental humidity. Therefore, the effects of the environment, temperature and humidity, are discussed to find the appropriate operation conditions for skin moisture detection. Besides, the application of the moisture sensor for the environment detection is also described. The IDC structure is fabricated by using printed circuit board (PCB) technology which simplifies the bonding technique and reduces the cost.     

基于MEMS工艺的SOI高温压力传感器设计

利用MEMS(微机电系统)工艺中的扩散,刻蚀,氧化,金属溅射等工艺制备出SOI高温压力敏感芯片,并通过静电键合工艺在SOI芯片背面和玻璃间形成真空参考腔,最后通过引线键合工艺完成敏感芯片与外部设备的电气连接.对封装的敏感芯片进行高温下的加压测试,高温压力测试结果表明,在21℃(常温)至300℃的温度范围内,传感器敏感芯片可在压力量程内正常工作,传感器敏感芯片的线性度从0.9 985下降为0.9 865,控制在较小的范围内.高温压力下的性能测试结果表明,该压力传感器可用于300℃恶劣环境下的压力测量,其高温下的稳定性能为压阻式高温压力芯片的研制提供了参考.     

光纤光栅解调系统的设计研究

本文设计了一种基于FPGA的光纤光栅解调系统,核心模块采用了FPGA芯片,型号为EP2C5Q208C8N,开发环境采用的是Quartus Ⅱ 9.1和Eclipse。通过软硬件相结合的方式,配置了一个NiosⅡ处理器软核,模数转换部分采用12位高精度转换芯片AD9226对采集到的温度信号进行实时转换,用VHDL硬件描述语言配置软核处理器,生成了一个适用于硬件系统的专用C环境,用C代码实现对硬件电路的控制。本文设计的高精度温度测量系统,能使光纤光栅传感器的中心波长随着温度的增加而逐渐增加,其信号波长与温度变化的斜率约为0.02nm/℃。     

A novel bonding method for fabrication of PMMA nanofluidic chip with low deformation of the nano-trenches

All PMMA-based nanofluidic chips are becoming increasingly important for biological and medical applications. To fabricate PMMA nanofluidic chips, the open nano-trenches should be sealed by thermal bonding method. However, the present thermal bonding method suffers from high deformation of nano-trenches due to PMMA softening near glass transition temperature. In this work, a novel bonding technique, based on acetone and ethanol (v:v, 8:2) treatment, is developed to adjust the Young’s modulus of PMMA in its surface layer. By optimizing nanoimprinting and bonding process, PMMA nanofluidic chip was fabricated without undesired nano-trench deformation. The integrity of the enclosed PMMA nanofluidic system was verified by a fluorescence filling experiment.