冲击硅微机械加速度传感器的封装与封装性能分析

给出了一种压阻式冲击硅微机械加速度传感器的器件封装结构并对其封装的性能进行了分析.加速度传感器的封装采用可伐合金做管壳,采用环氧粘合剂将芯片粘结在金属基板上,采用金丝连接芯片铝焊点和管脚,使用环氧灌封胶充填管壳内空余的区域,来缓冲芯片受到冲击时承受的冲击应力.用ANSYS软件对封装后的器件进行了模态分析.分析结果表明,封装后加速度传感器敏感结构--悬臂梁敏感方向上的模态频率与封装前基本相同,封装后器件管壳三个破坏方向上的模态频率足够大.因此,封装不影响加速度传感器的测试性能并有良好的抗冲击能力.用霍普金森杆对封装后器件进行了冲击破坏实验.实验结果表明,引线从芯片铝焊点处脱落是冲击破坏的主要形式.     

硅压力传感器的应力隔离封装

<正> 当封装压力传感器时,由于传感器芯片和管壳材料之间热膨胀系数的差别,在封接部位引入应力。这一封装应力引起传感器芯片硅膜     

封装抗辐射加固技术研究

封装加固通过屏蔽空间辐射的方式避免芯片受到影响,对空间辐射中的总剂量效应有明显效果.在实际应用中,必须根据集成电路工作时的所处辐射环境,如所在轨道、主要辐射源等,选择相应的屏蔽材料以实现有针对性的封装加固.基于对空间辐射带环境以及辐射效应影响的详细阐述,从金属材料屏蔽、金属-陶瓷屏蔽、薄膜屏蔽、塑封屏蔽等角度,提出封装...     

MEMS压阻式压力传感器倒装焊封装的研究和发展

介绍了倒装焊接技术在MEMS压阻式压力传感器封装领域的优势和目前研制的压力敏感芯片的倒装焊的关键技术。根据封装结构设计和基板材料的不同,详细论述了国内外MEMS压阻式压力传感器倒装焊技术的研究成果。最后总结了MEMS压力传感器倒装焊技术的发展前景和所面临的挑战。     

软封装

有的电子爱好者把电路板上的某部分或体积较小的电路板密封起来,不让水气、灰尘和异物进入影响电路的性能,而采用蜡或沥青作密封胶。其实蜡和沥青作包封材料缺点很多。目前通用的最佳软包封材料,大致有聚硫化物、聚氨基甲酸酯、有机硅和环氧树脂等四个体系。用这些材料封装就是所谓软封装。它不需要利用封装外壳来进行集成电路芯片的安装和保护,而是借助于有机材料的印制线路板或陶瓷金属化布线基片,将芯片直接安置在预定的位置上,并利用金属线将芯片各输出、输入端与印制线路或金属化布线     

英飞凌面向安全关键型汽车应用推出双传感器封装器件

正英飞凌近日发布的线性霍尔传感器和角度传感器这两个器件家族已经使用了新型双传感器封装。它可支持ASIL D,并且降低了物理空间要求和系统成本。通过采用创新堆栈贴装技术,这种线性霍尔传感器和角度传感器家族器件将两颗独立的传感器合并到一个厚度仅为1毫米左右的小巧的标准PG-TDSO封装中。英飞凌并未采用并排放置传感器的常见做法,而是利用已获得专利的倒装芯片技术,将两颗传感器堆叠起来。这能在     

论芯片封装技术及其发展前景

作为微电子技术领域中的一项重要技术,芯片封装技术在最近几十年的时间里获得了较快的发展,也取得了长足的进步。随着时代的变迁与发展,芯片封装技术也经历了多个发展阶段,逐步出现了几种具有代表性的芯片封装技术。本文将围绕芯片封装技术展开进一步的讨论,主要探讨了其发展前景,认为芯片封装技术将在未来很长一段时间里都是计算机微电子行业中非常重要的技术。     

MEMS封装技术

介绍了微机电(MEMS)封装技术,包括晶片级封装、单芯片封装和多芯片封装、模块式封装与倒装焊3种很有前景的封装技术。指出了MEMS封装的几个可靠性问题,最后,对MEMS封装的发展趋势作了分析。     

LED芯片封装缺陷检测方法研究

引脚式LED芯片封装工艺中封装缺陷不可避免.基于p-n结的光生伏特效应和电子隧穿效应,分析了一种封装缺陷对LED支架回路光电流的影响.利用电磁感应定律对LED支架回路光电流进行非接触检测,得到LED芯片功能状态及芯片电极与引线支架问的电气连接情况,并对检测精度的影响因素进行分析.实验表明,该方法具有高检测信噪比,能够实现对封装过程LED芯片功能状态及封装缺陷的检测.计算结果与实验结果较好吻合.     

MEMS封装技术研究进展与趋势

介绍了MEMS(microelectromechanicalsystems)封装技术的研究现状和存在的问题,重点介绍了倒装芯片技术(flip chiptechnology简称FCT)、上下球栅阵列封装技术和多芯片模块封装技术三种很有前景的封装技术的特点及其在MEMS领域的应用实例,并且对MEMS封装有可能的发展趋势进行了分析。     

Temperature characterization of flip-chip packaged piezoresistive barometric pressure sensors

In order to miniaturize piezoresistive barometric pressure sensors, a new flip-chip packaging technology has been developed. The thermal expansions of chip and package are different. So in a standard flip-chip package the strong mechanical coupling by the solder bumps would lead to stress in the sensor chip, which is unacceptable for piezoresistive pressure sensors. To solve this problem, in the new packaging technology the chip is flip-chip bonded on compliant springs to decouple chip and package. As the first step of the packaging process an under bump metallization (UBM) is patterned on the sensor wafer. Then solder bumps are printed. After wafer-dicing the chips are flip-chip bonded on copper springs within a ceramic cavity housing. Due to the compliance of the springs, packaging stress is induced into the sensor chip. As sources of residual stress the UBM and the solder bumps on the sensor chip were identified. Different coefficients of thermal expansion of the silicon chip, the UBM and the solder lead to plastic straining of the aluminum metallization between UBM and chip. As a consequence the measurement accuracy is limited by a temperature hysteresis. The influence of the chip geometry, e.g., the thickness of the chip or the depth of the cavity, on the hysteresis was investigated by simulation and measurements. As a result of this investigation a sensor chip was designed with very low residual stress and a temperature hysteresis which is only slightly larger than the noise of the sensor.     

A FCOB packaged thermal wind sensor with compensation

A two dimensional wind sensor was designed, fabricated and packaged on ceramic substrate instead of silicon substrate. The Ti/Pt heater and thermistors were fabricated using single lift-off process. The gold bumps were then sputtered and patterned on the chip using lift-off process again. Correspondingly, the Pb/Sn bumps were fabricated on the FR4 substrate using stencil printing method after metallization. The sensor chip was flip-chip packaged on the FR4 substrate, and the gap was filled with epoxy-based underfill to improve the structure strength. The packaged sensor was tested in wind tunnel in constant power mode. The wind velocity and direction offsets of the sensor were compensated using software and hardware calibration. Both the simulation and test results show that the thermal wind sensor can measure wind speeds up to 8 m/s with an accuracy of 0.3 m/s, and wind direction in a full range of 360° with a resolution within 5°.     

倒装芯片封装技术概论

高密度电子封装正朝着小型化、高I/O密度、更好的散热性和高的可靠性方向发展,传统引线键合技术已经无法满足要求。先进的倒装芯片封装技术由于具有较高的单位面积内I/O数量、短的信号路径、高的散热性、良好的电学和热力学性能,在电子封装中被广泛关注。底部填充胶被填充在芯片与基板之间的间隙,来降低芯片与基板热膨胀系数不匹配产生的应力,提高封装的稳定性。然而,流动底部填充胶依赖于胶的毛细作用进行填充,存在很多缺点。为了克服这些缺点,出现了非流动底部填充胶,以改善倒装芯片底部填充工艺。文章回顾了倒装芯片封装技术的发展,阐述了流动和非流动底部填充胶的施胶方式和性质。     

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.     

基于倒装技术的电容式绝对压力传感器研究

信号处理与气密封装是电容式压力传感器设计的主要难题.本文提出一种新型的绝对压力传感器结构,利用倒装技术在基片上制作电路和柱状凸点,通过回流焊接将凸点和预先加工好的膜片封接在一起,实现气密封装和电路集成,并通过金属凸点完成电极的转移.测试结果表明传感器的性能良好,在灵敏度19fF/kPa的情况下获得了良好的线性.     

Low-power gas sensors based on work-function measurement in low-cost hybrid flip–chip technology

To implement low-power gas sensors with low component costs, the principle of work-function read out via a hybrid suspended gate FET (SGFET) is being pursued, whereby a freely selectable sensor film undergoes a reversible work-function change corresponding to the build-up of a potential difference on the surface in response to gas adsorption/reaction. This is read out via an ISFET structure. An innovative design which allows cheap manufacturing will be described for the principle that has already been successfully demonstrated. The starting point of the design is a ceramic Al₂O₃ substrate coated with conductor patterns and sensitive materials onto which the FET is mounted in flip–chip technology. By means of the freely selectable sensor film and its preparation method, a wide range of applications can be opened up.     

Parametric study of flip-chip packaging for an MEMS device with diaphragm

A backside-etched silicon chip with a polysilicon diaphragm flip-chip attached on a printed wiring board and globally bumped on a FR4 printed circuit board was investigated through a finite element analysis for determining three key parameters of flip-chip chip size packaging, namely, the size of solder bump, and the thickness of the printed wiring board with/without U8437-3 underfill. Four kinds of thermal-induced stresses and deformations in the diaphragm, solder bump, and printed wiring board were evaluated for the parametric study. As the simulation results show, the thermal-induced stresses in the diaphragm and solder bump can be reduced effectively if the printed wiring board is thinner. However, the printed wiring board is still required to be sufficiently thick to prevent warping. In addition, the underfill material also can reduce the induced stress occurring at the interface between the solder joint and the chip and improve reliability. In general, the parametric study can provide a basis for the flip chip package of a MEMS device with a diaphragm, such as a MEMS microphone, MEMS pressure sensor, etc.     

基于非共烧技术的高温压力传感器设计

设计一种基于氧化锆( ZrO2 )的高温非共烧陶瓷压力传感器.在已有的低温共烧陶瓷( LTCC)工艺的基础上,经过改进采用了高温非共烧技术进行陶瓷传感器的制作.先进行传感器基底的制作,再制作传感器的金属电路部分.这样解决了高温共烧技术中各材料高温烧结热膨胀系数不匹配的问题.传感器信号读取采用两个电感耦合的方式,实现了非接触压力测量.制作的传感器高温环境下力学特性稳定.测试结果显示:传感器的谐振频率随外加压力的增加而减小,其谐振频率变化对压力的响应灵敏度约为491. 10 kHz/bar.     

Flip chip solder bump inspection using vibration analysis

Flip chip technology is an attractive choice for high-density packaging and complex microsystem architectures. A critical element in the successful application of flip chip technology is the reliability of solder bumps. In this paper a nondestructive detection method is presented for the flip-chip solder bump inspection using ultrasonic excitation and vibration analysis. Simulations are implemented to explore the feasibility of this method, and experimental investigations are also performed, where the flip chips are excited by continuous ultrasonic waves and their vibration velocities are measured by a laser scanning vibrometer for further analysis. The results reveal that the defective chips can be distinguished from the good chips by the chip vibration velocities with the feature coefficient α, which proves the effectiveness of this method. Therefore, it may provide a new path for the improvement and innovation of flip chip on-line inspection systems.     

一种新型无源电容式温度传感器的制备与测试

为了实现高温、机械旋转和密闭空间等恶劣环境中的原位温度测量,以高居里点的铁电陶瓷为温度敏感介质材料,在传统低温共烧陶瓷(LTCC)工艺的基础上,采用牺牲层填充技术,保证了制备过程的工艺兼容性,成功制备出了一种基于LTCC衬底的新型无源电容式温度传感器。通过外部读取天线与传感器线圈的互感耦合,实现了从常温至700℃的传感器温度特性测试,测试结果表明:这种电容式温度传感器具有良好的温度敏感特性,其平均灵敏度为-7.33 kHz/℃。