平行缝焊机的阵列焊设计

在电子设备的使用中,会遇到各种苛刻环境条件,如潮湿、酸雨和盐雾等.在这种情况下,器件可能因电化学腐蚀而缓慢失效,也可能因水汽渗入而性能劣化.因此,对器件进行性能优良的气密性封装,有效保护器件免受外界环境的影响至关重要.平行缝焊是最常用的气密性封装方法之一,属于电阻焊.传统的平行缝焊设备单个焊接效率低下,为了提高焊接效率,提出了带阵列焊功能的平行缝焊机.     

基于异质金属接触电化学腐蚀的MMIC阻性衰减器失效分析

针对某单片微波集成电路(MMIC)阻性衰减器断路故障进行了失效分析.开封后,利用扫描电子显微镜(SEM)、能谱仪(EDS)和聚焦离子束(FIB)等对失效样品进行检测.经检测发现W电阻薄膜断裂导致器件断路失效.W电阻薄膜断裂的原因是W-Au异质金属直接接触的区域暴露在空气中形成腐蚀原电池发生电化学腐蚀.利用质量分数3％的NaCl溶液对同批次器件进行腐蚀实验,复现了失效模式.检测和复现实验证明了该器件的失效机理为基于异质金属接触的电化学腐蚀.     

平行缝焊与盖板

在一些特殊环境条件下使用的各种电子元器件,需要进行密封封装,以防止器件中的电路因潮气、大气中的离子、腐蚀气氛的浸蚀等引起失效。另外在封装时可以充以保护气体来降低封装环境湿度,进行气密性封装以延长器件的使用时间。文章通过在SSEC（Solid State Equipment Company）M-2300型平行缝焊机上进行缝焊实验发现,盖板与平行缝焊的关系是相当重要的。在管座性能稳定的情况下,盖板质量的好坏直接影响着器件的气密性。     

无损氦质谱检漏

用于集成电路的管壳,除在散热、电气性能和机械强度等方面应满足器件要求外,还要求尽可能密封。对气密性封装来说,密封性通常是可以保证的。然而由于零部件质量或工艺操作等种种因素,个别器件往往出现漏气。这种漏气的器件,在使用过程中由于周围气氛的侵入,从而引起器件性能的劣化甚至完全失效。从而大大降低了产品的可靠性水平。通常采用对器件100％进行潮湿试验的办法,淘汰因气密性不好而早期失效的器     

集成电路封装用绝缘胶漏电失效分析

在电子元器件封装领域中,塑封器件正逐步替代气密性封装器件。目前工业级塑封器件已不能满足器件的高可靠性要求,工业级塑封器件在严酷的环境应力试验中经常出现失效。研究了工业级塑封器件在可靠性筛选试验中出现失效的问题,通过X射线观察和芯片切面分析等方法,查明了造成器件失效的原因,并提出了优化改进措施。     

密封封装内部水汽含量判据研究

密封封装内部的水汽对于半导体器件的可靠性是一种威胁,由此导致的硅表面铝金属线的腐蚀是一种主要的失效机理。为了防止密封封装内部发生腐蚀失效,从而提高器件的可靠性,美军标和我国国军标均给出了内部水汽含量的试验流程和判据。然而另一些研究表明,水汽的单独存在并不会导致铝线腐蚀失效。研究了水汽在密封器件的腐蚀失效机理中的作用,对硅表面铝线的腐蚀过程进行了数学描述,分析了目前标准中内部水汽含量判据,并给出了防止密封器件腐蚀失效的建议。     

MEMS器件各向异性腐蚀过程中的AI连线保护

微电子机械系统(MEMS)器件制造过程中的各向异性腐蚀工序，会引起硅片正面的AI连线被腐蚀，造成器件的失效。本文论述了使用一种环氧树脂和聚酰胺调配的胶体将器件正面电路密封起来的方法，使MEMS器件在85℃，浓度为33％的KOH溶液里进行各向异性腐蚀，可以成功地保护AI连线。这种方法的使用，为MEMS器件的制作完成奠定了技术基础。     

硅基梳齿式MEMS器件及封装的失效调查

对典型硅基梳齿式MEMS器件进行失效调查和分析,验证其主要失效模式,分析其失效机理.利用电子扫描显微镜(SEM),X射线透视系统、扫描声学显微镜(SAM),X射线能谱成份分析(EDX)、金相切片分析、封装气体分析及电性能测试等分析技术,发现在工艺制造中的机械失效是造成此类器件失效的主要原因.另外,此类器件的封装失效主要表现为气密性失效和装配工艺失效.     

关于铝电解电容器腐蚀失效的研究进展

总体概括了近些年铝电解电容器的失效现象、机理研究及防止电解电容失效的一些重要措施。重点总结出了铝电解电容器阳极腐蚀发生的原因，电化学腐蚀的机理、反应过程及腐蚀表现，将为以后研究阳极腐蚀的学者提供一定的参考。     

梳齿式MEMS加速度计在冲击下的失效分析

对Si基梳齿式MEMS加速度计在冲击下进行了失效分析,验证了其主要失效模式,分析了其失效机理。通过机械冲击实验并采用扫描电镜(SEM)、X射线透视系统、扫描声学显微镜(SAM)观察及电性能测试等分析技术,研究了梳齿式MEMS加速度计在冲击载荷下的结构与封装失效,运用材料力学理论加以分析论证,发现悬臂梁断裂是较为主要的失效模式,且此类器件的封装失效主要表现为气密性失效和装配工艺失效,为MEMS器件的可靠性设计提供了重要依据。     

Insights into corrosion in dye solar cells

The main issue in using low cost metals in dye solar cells is the corrosion caused by the liquid electrolyte. Contrary to typical applications of metals, the adverse effects of corrosion in dye solar cells are related to irreversible depletion of charge carriers from the electrolyte rather than consumption of the metal itself. It is calculated that the penetration rate due to corrosion should not exceed 10⁻⁴ mpy (a couple of nanometers per year) to ensure device lifetime longer than 1 year. This is 10 000 times slower rate than what is considered to be a general benchmark value for very low corrosion rate in the field of corrosion science and has a major effect on how corrosion should be investigated in the case of dye solar cells. Different methods, their applicability, and limitations to investigate corrosion in dye solar cells are evaluated here. The issue with most techniques is that they can detect metals that are clearly corroding, but they have significant limitations in proving a metal stable. Our investigation shows that the most reliable information on corrosion is obtained from complete dye solar cells that are exposed to working conditions. A combination of color analysis of the electrolyte to such measurement is proposed as a means to extrapolate future performance of the cells and estimate potential lifetimes of the dye solar cells in regards to corrosion. Copyright © 2014 John Wiley & Sons, Ltd.     

基于绿色再制造的火车车钩裂纹激光修复和表面强化

车钩是铁路车辆的关键部件之一,钩尾销孔承载面产生的裂纹是其主要失效形式.为了实现对车钩的绿色再制造,文中通过实验研究了激光熔覆技术在车钩裂纹修复方面的应用,并分析了熔覆材料的硬度分布、耐磨性、低温冲击韧性以及结合区域的微观组织特征.实验结果表明,熔覆材料与基体实现了冶金结合,硬度分布合理,耐磨性和低温冲击韧性都比母材有了较大提高,为开展产业化的绿色再制造奠定了基础.为了防止新造车钩出现裂纹,提出了一种新的激光淬火工艺,替代原有的中频淬火工艺,实验结果表明,激光淬火的硬度和耐磨性都比中频淬火有较大提高,而且兼顾了车钩总体的力学性能,可以在实际生产中应用.     

Colorimetric visualization of tin corrosion: A method for early stage corrosion detection on printed circuit boards

A majority of printed circuit board surfaces are covered with tin, therefore tin corrosion under humid conditions and movement of tin ions under the influence of an electric field plays an important role in the corrosion failure development. Tracking tin corrosion products spread on the printed circuit board assembly (PCBA) provides a basis for the mechanistic understanding of PCBA corrosion failures and leak current tracks which eventually can lead to electrochemical migration. This paper presents a method for identification of such failures at the early stage of corrosion by using a colorimetric tin ion indicator applied as a gel. The examples provided in this paper include visualization of corrosion caused by weak organic acids found in solder fluxes, corrosion profiling on the PCBAs after climatic device level testing, and failure analysis of field returns.     

随钻测量定向接头失效形式及原因分析

随钻测量技术广泛应用于钻井、测井、地质分析等工程中,无磁随钻测量定向接头是井下随钻测量仪器的重要部件,通过研究无磁随钻测量定向接头的失效形式并加以分析,使我们从中得到了无磁随钻测量定向接头的腐蚀失效原因,并知道腐蚀失效的存在会增加接头断裂的风险率.为此我们会在日常维护中利用外观检测和超声波检测仪对设备加以检测,以排除隐患来降低事故的发生率.     

贴片式电子元件典型的失效模式及机理分析

针对贴片式电阻器和贴片式陶瓷电容器中银电极典型的腐蚀漏电失效模式,选取两个案例进行分析。通过采用X-ray、金相切片和SEM&EDS等分析手段,阐述了这类贴片式电子元件的失效机理,剖析了元件出现硫化腐蚀、电化学迁移失效与银电极制作工艺及电极浆料的关系,并提出了有效控制此类失效的措施与对策。     

Field failure due to creep corrosion on components with palladium pre-plated leadframes

Creep corrosion is a mass-transport process during which solid corrosion products migrate over a surface. It has been identified as a failure mechanism responsible for the malfunction of electrical contacts and connectors. For components with noble metal pre-plated leadframes, creep corrosion is a potential reliability risk for long-term field applications. This paper explains the source, process and possible products of creep corrosion on integrated circuit (IC) packages. The operating environment for telecom equipment is introduced as an example demonstrating the corrosive environments for electronic components. Field failure due to creep corrosion on plastic encapsulated components with palladium pre-plated leadframes is presented and analyzed. Similar phenomenon has been reproduced in an accelerated manner using mixed flowing gas (MFG) testing in the laboratory.     

Novel failure mode of chip corrosion at automotive HALL sensor devices under multiple stress conditions

Semiconductor devices used in automotive applications undergo numerous stress situations depending on their particular application. Corrosion, as one main crucial failure mechanisms, can affect the lifetime of electronic components on system, device or even die level. In this paper, a novel corrosion mechanism on HALL sensor devices is investigated and clarified. This corrosion is only occurring under complex conditions like layout aspects, ionic impurities combined with humidity penetration and thermo-mechanical strain due to packaging and additional mechanical load from further over moulding. It is shown how advanced physical and chemical analysis can be combined with finite element simulation to ascertain a chemical degradation running on silicon, silicon dioxide and metallisation level to derive the complete chemical reaction mechanism for the observed corrosion defects. To verify the new failure mode, experiments to recreate this type of corrosion were carried out. Finally, conclusions are drawn on how failure modes can be prevented and how the robustness of the HALL devices under harsh environments can be increased.     

A novel approach to stabilize contact resistance of electrically conductive adhesives on lead-free alloy surfaces

Electrically conductive adhesive (ECA) is an alternative for the toxic lead-based solders. However, unstable electrical conductivity has long been a haunting problem. Galvanic corrosion at the ECA/pad interface has recently been found to be the major mechanism for this decay. Applying a more active metal or alloy on a dissimilar metal couple in contact can prohibit galvanic corrosion. In this study, powders of aluminum, magnesium, zinc, and two aluminum alloys were added in an ECA and applied on five pad surfaces. The aging of the bulk resistivity and contact resistance of the ECA/metal surface pairs were studied. The two alloys significantly suppressed the increase of the contact resistance on all tested metal surfaces.     

Non‐Corrosive,Non‐Absorbing Organic Redox Couple for Dye‐Sensitized Solar Cells

A new colorless electrolyte containing an organic redox couple, tetramethylthiourea (TMTU) and its oxidized dimer tetramethylformaminium disulfide dication ([TMFDS]²⁺), is applied to dye‐sensitized solar cells (DSCs). Advantages of this redox couple include its non‐corrosive nature, low cost, and easy handling. More impressively, it operates well with carbon electrodes. The DSCs fabricated with a lab‐made HCS‐CB carbon counter‐electrode can present up to 3.1% power conversion efficiency under AM 1.5 illumination of 100 mW·cm^?2 and 4.5% under weaker light intensities. This result distinctly outperforms the identical DSCs with a Pt electrode. Corrosive experiments reveal that Al and stainless steel (SS) sheets are stable in the [TMFDS]²⁺/TMTU‐based electrolyte. Its electrochemical impedance spectrum (EIS) is used to evaluate the influence of different counter‐electrodes on the cell performance, and preliminary investigations reveal that carbon electrodes with large surface areas and ideal corrosion‐inertness toward the sulfur‐containing [TMFDS]²⁺/TMTU redox couple exhibit promise for application in iodine‐free DSCs.     

铜丝键合在实际应用中的失效分析

研究并总结了铜丝键合塑封器件在实际应用环境中工作时发生的几种不同失效模式和失效机理,包括常见封装类型电路的失效,这些封装类型占据绝大部分铜丝键合的市场比例。和传统的实验室可靠性测试相比,实际应用中的铜丝失效能够全面暴露潜在可靠性问题和薄弱点,因为实际应用环境存在更多不可控因素。实际应用时的失效或退化机理主要包括:外键合点氯腐蚀、金属间化合物氯腐蚀、电偶腐蚀、键合弹坑、封装缺陷五种类型。对实际应用中的数据和分析为进一步改善铜丝键合可靠性、提高器件稳定性提供了依据。