共查询到19条相似文献,搜索用时 109 毫秒
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针对橡胶材料与金属板粘接样件厚度及粘接质量,采用反射式太赫兹时域光谱(THz- TDS)系统对其进行无损检测。通过对检测数据中各点时域波形飞行时间信息的分析,得到样件橡胶部分的二维厚度分布图,实现了橡胶样件厚度分布的可视化成像;通过对检测数据中特征点波形及B-Scan图像的综合分析,判断出样件的分层缺陷。该研究结果为橡胶材料厚度及分层缺陷的无损检测提供了有效的解决办法。 相似文献
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相移迁移法在激光超声合成孔径聚焦技术中的应用 总被引:1,自引:0,他引:1
通过分析脉冲源激光辐照于工件表面激发的多模式、宽带超声体波信号并结合合成孔径聚焦技术(SAFT),实现了对工件内部微小缺陷的检测、定位和成像。首先基于有限元仿真模拟了激光激发超声波在含缺陷样品中的传播过程,编写了基于相移迁移法(PSM)的SAFT成像算法,然后在实验中使用激光在含缺陷样品表面激发超声波,使用激光测振仪探测超声波,并基于已有算法和探测结果对样品内缺陷进行了检测和定位,以验证算法的正确性。有限元仿真以及实验结果均表明,将激光超声技术与频域SAFT-PSM结合,能够有效地对微小缺陷进行检测和定位,且其图像重构速度快于时域SAFT,可为激光超声无损检测提供更快速的实时技术方案。 相似文献
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蔡少英 《电子产品可靠性与环境试验》1996,(1)
集成电路封装的可靠性在许多方面要取决于它们的机械完整性.由于不良键合、孔隙、微裂痕或层间剥离而造成的结构缺陷可能不会给电性能特性带来明显的影响,但却可能造成早期失效.C模式扫描声学显微镜(C—SAM)是进行IC封装非破坏性失效分析的极佳工具,可为关键的封装缺陷提供一个快速、全面的成象.并能确定这些缺陷在封装内的三维方位.这一C—SAM系统已经在美国马里兰州大学用于气密性(陶瓷)及非气密性(塑料)IC封装的可靠性试验。它在塑料封装常见的生产缺陷如:封装龟裂、叶片移位、外来杂质、多孔性、钝化层龟裂、层间剥离、切断和断裂等方面表现出很高的无损鉴别效率.C—SAM还是表面安装研制方面的有力工具.它在表面安装过程中检测塑料IC封装由潮湿和热引起的损害方面起关键性的作用。封装在经受加速环境(如高温、高湿度)的过程中,C—SAM还可用于封装的连续监控。用C—SAM还可通过无损方式获得剖面成象,提供有接面深度的信息(时间和厚度),这些信息可用于计算封装中孔隙的深度或裂缝的长度。 相似文献
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通过对超声检测技术的原理进行分析,并将其与X射线检查和制样镜检技术分别进行对比,阐述了超声检测技术在检测片式多层瓷介电容器(MLCC)的裂纹、 分层和空洞等内部缺陷方面的优势.对超声显微镜的扫描原理和扫描模式进行分析,确定了MLCC内部空洞缺陷超声检测的判定方法.并利用B扫描模式对ML-CC的叠层空洞进行了判别和区分,对于提高MLCC超声检测技术检测结果的准确性具有指导意义. 相似文献
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为了实现材料内部微小缺陷的非接触无损检测,解决激光超声检测内部缺陷时衍射回波信号弱、透射体波检测无法获得缺陷深度信息等问题,提出了一种激光超声反射横波双阴影检测方法。该方法结合超声透射法和反射法的优点,依据缺陷对反射横波的两次衰减作用,利用时间飞行法对样品进行扫描检测,通过波形互相关算法计算波形时延,精确测量了激光激发点与探测点距离和横波双阴影间距,结合样品厚度实现了对直径为0.8 mm内部缺陷的检出和深度定位。与X射线数字射线照相、传统超声换能器检测的结果进行对比后可知,激光超声方法能够实现材料内部微小缺陷的非接触无损检测和精确定位。 相似文献
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Scanning acoustic microscopy is an imaging method in which the focused high frequency ultrasound is used to visualize the micro structures. The morphology and acoustic properties of the biological tissues can be evaluated using scanning acoustic microscope system. To determine thin tissues having micrometer thickness, the high acoustic frequency is required for conventional SAM. In practice the acoustic frequency is restricted by the penetration depth through the material. Characterization of thin sliced tissue is difficult, as the reflected signals from top and bottom are superimposed. In order to improve the axial resolution of conventional SAM, a technique based on sparse signal representation in overcomplete time–frequency dictionaries is investigated and among the great number of algorithms for finding sparse representation, we first apply matching pursuit (MP) and basis pursuit (BP) and then propose the orthogonal matching pursuit (OMP) and stagewise orthogonal matching pursuit (StOMP) algorithms to decompose the A-scan signal to an overcomplete Gabor dictionary. Different criteria are used for measuring the performance of these algorithms in C-scan imaging. The proposed method can separate closely space overlapping echoes beyond the resolution of conventional SAM systems and also the final results show that StOMP performs best overall in extracting the specific echo, since this algorithm is precise and fast. 相似文献
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Yalamanchili P. Christou A. Martell S. Rust C. 《Circuits and Devices Magazine, IEEE》1994,10(4):36-41
C-mode acoustic microscopy provides unique advantages over SLAM techniques in detecting microcracks, voids, and delaminations. The reliability of integrated circuit (IC) packages depends in many respects on their mechanical integrity. The effect of structural weaknesses caused by poor bonding, voids, microcracks or delaminations may not be evident in the electrical performance characteristics, but may cause premature failure. C-mode scanning acoustic microscopy (C SAM) is an excellent tool for non-destructive failure analysis of IC packages. It provides a rapid and comprehensive imaging of critical package defects and the location of these defects in three dimensions within the package 相似文献
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Tang C.W. Chan Y.C. Hung K.C. Webb D.P. 《Advanced Packaging, IEEE Transactions on》2001,24(2):163-168
Flip chip technology is the emerging interconnect technology for the next generation of high performance electronics. One of the important criteria for reliability is the width of the gap between the die and the substrate, i.e., the standoff height. A nondestructive technique using scanning acoustic microscopy (SAM) for the standoff height measurement of flip chip assemblies is demonstrated. The method, by means of the implementation of a pulse separation technique, time difference of the representative signals of the die bottom and water interface and water and substrate surface interface from the A-scan image can he found. Then, the corresponding standoff height can be calculated. When compared to the traditional destructive measurement method (SEM analysis on sectioned sample), this nondestructive technique yields reliable results 相似文献
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Solder joint cracking is a common failure mechanism in microelectronic packages. To investigate interconnect integrity and reliability different inspections are established with their strengths and weaknesses: X-ray, scanning acoustic microscopy (SAM), Infrared (IR)-Thermal Imaging as well as Transient Thermal Analysis (TTA). TTA is well suited to detect changes in the thermal path, i.e. delamination in a package. However, spatial resolution in plane of an interconnection is restricted. Still, spatial resolution is necessary to analysis the crack growth in solder joints. In addition the local temperature strongly depends on the local position of a bad thermal contact. In the paper an innovative new test method, location resolved transient thermal analysis (LrTTA), is developed and its potential is investigated. LrTTA is based on transient thermal measurement (TTM). It uses several distinct diodes on a test chip to detect the thermal performance of interfaces and assemblies. The temperature is measured by the forward voltage as a function of time at different locations on the chip. Spatial resolution is obtained, e.g. cracks, voids and thickness variations can be resolved in the interface. For first experimental application of the method, a silicon thermal test chip with four differently located diodes was employed. The test chip was soldered onto an Aluminium Insulated Metal Substrate (Al-IMS) and exposed to temperature cycles. TTM were performed directly after assembly and after specific temperature shock cycle numbers (− 40 °C/+125 °C). After data processing, the increase of the thermal impedance of each diode between the initial “0” cycles and “n” cycles was obtained. The thermal data are correlated with void formation detected by X-ray. Crack or delamination is in addition detected with scanning acoustic microscopy (SAM). As a quantitative analysis, a finite element (FE) model was set up and applied to analyze the solder joint with and without voids and also the crack propagation in the solder joint during temperature shock testing. Based on the FE modelling, the thermal influence of voids can be calculated and thus these voids can be detected. Further, based on the numerical analysis, crack size and location can be identified. 相似文献
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柳思泉 《电子产品可靠性与环境试验》2011,29(2):49-53
通过对超声显微成像技术(AMI)检测原理的分析,阐述了AMI在检测片式多层瓷介电容器(MLCC)裂纹、分层和空洞等内部缺陷方面的具体应用,其检测结果得到了破坏性物理分析(DPA)的验证.此外,还讨论了不同频率的超声波传感器对AMI检测结果的影响,对提高AMI检测结果的准确性具有指导意义. 相似文献
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Lau J.H. Chang C. Lee S.-W.R. 《Electronics Packaging Manufacturing, IEEE Transactions on》2000,23(1):19-27
Failure analyses of 63/37 Sn/Pb solder bumped flip chip assemblies with underfill encapsulant are presented in this study, Emphasis is placed on solder flowed-out, nonuniform underfill and voids, and delaminations. The X-ray, scanning acoustic microscope (SAM), and tomographic acoustic micro imaging (TAMI) techniques are used to analyze the failed samples. Also, cross sections are examined for a better understanding of the failure mechanisms. Furthermore, temperature dependent nonlinear finite element analyses together with fracture mechanics are used to determine the effects of underfill void sizes on the flip chip solder joint reliability 相似文献
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超声扫描检测因为其灵敏度高、对样品没有损伤的特点,被广泛地应用到塑封器件的筛选和检测中,但是目前不存在一个完整的超声扫描检测方法。对塑封器件缺陷进行分析,提出一种塑封器件缺陷的超声扫描检测方法。该方法采用A扫描与C扫描检测塑封器件内部的缺陷,其过程为塑封体缺陷检测与重要界面缺陷检测。与现有GJB 4027A要求的聚焦6个重要界面的检测方法相比,本方法只需要聚焦两个界面即可观察到6个界面的情况,可以提升检测效率。 相似文献
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Jicheng Yang 《Microelectronics Reliability》1996,36(9):1291-1295
Scanning acoustic microscopy (SAM) has emerged as a powerful tool for the detection of defects in ceramic or plastic packaged integrated circuits. At the Singapore Institute of Standards and Industrial Research, we have been using SAM to identify packaging and/or assembly related defects across a broad spectrum of integrated circuit packages. In many cases, it has been the only technology available that is capable of quickly and non-destructively determining the precise failure mode, such as delamination. 相似文献
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硅/硅键合片在MEMS器件的生产中得到了应用。如果硅片的表面被微观粒子或被污染液体中的残余物所沾污,硅/硅键合界面就会产生空洞。如果这些空洞没有被及时发现,将给后道工序带来严重的问题,并降低成品率。超声显微成像对于不同材料的界面反应非常敏感,对硅/硅界面存在的空洞很容易声学成像。使用超声显微成像能够检测到键合界面存在的空洞,因而可以把有缺陷的硅片在造成进一步的损失之前清除掉。高分辨率的超声显微成像可以辨别出直径5μm的空洞。 相似文献