肖特基二极管防护后SCB静电安全性研究

为了提高半导体桥(SCB)火工品的静电安全性能,利用肖特基二极管(SBD)对SCB进行静电防护,对防护后的SCB火工品进行静电放电试验研究。研究结果表明:在静电放电条件（25 kV、500 pF、500 Ω）下,防护后的SCB火工品的桥区未烧蚀,电阻未发生明显变化,SCB未损伤。对静电试验后的SCB火工品进行电容发火试验研究,研究结果表明:静电试验后的SCB能够正常发火,SCB的爆发时间与发火能量未产生显著性变化,SCB的电爆性能未受到影响。     

火工品制造工艺的发展

火工品是指内部设有炸药或火药,在受到外界刺激后能够产生爆炸或燃烧,以点燃火药、引爆炸药或者是做机械工的一次性使用的装置与元器件的总称.如今,随着科学技术的不断发展,火工品也在人类日常生活中扮演着重要角色,小到节假日燃放的烟火爆竹,大至航天卫星的发射器,其制造工艺也是千变万化的。就火工品的发展历程,来对其制造工艺的发展做一下浅显的描述。     

论铁路工程施工火工品安全管理

本文通过对铁路工程项目施工火工品安全管理、工作流程、现场管控的描述,对有效控制火工品在购买、运输、储存、领用、发放等环节的安全进行了论证,对铁路工程项目施工中火工品安全管理有一定的指导意义。     

火工品销毁技术

火工品销毁技术１概述火工品是引燃发射药或引爆炸药的元件，包括火帽、雷管、电爆管、底火、史光管、抛射管、拉火管、推射管、点火具、传火具、导火索、导爆索．电燃撞针及动力切割火工品等。火工品的药剂有击发药、引火药、延期药、起爆药和炸药等。在火工品正常生产过...     

火工品生产中人体静电起电的探讨

一、静电对火工品生产的危害性在火工品的生产过程中,静电危害显得非常突出,常常由于意外的静电火花引爆药品,造成严重事故。例如,当操作者身穿毛衣和胶鞋,在橡皮地板上急步走入火工品工房,当手接近而未触及产品时,便发生爆炸;当半成品在塑料桌面上来回推送,而人坐在塑料面椅子     

婴儿培养箱校准问题及对策

对目前市场上常用的婴儿培养箱分析仪进行比较,分析了多种校准设备的优缺点,并就未来的改进方向提出看法;文章还对婴儿培养箱校准过程中,经常出现的接地电阻超差、断电无报警故障、温度均匀度超差及温度偏差超差等问题进行分析,并提出了解决方法与建议。     

点温计示值超差的调修

在检定半导体点温计示值时,常出现1/5～4/5量程范围内示值超差。经检查发现其原因是,测量电桥比例臂上的两个等值平衡电阻在不同环境下使用后,阻值不相等或阻值出现趋向性变化。而且,感温元件——半导体热敏电阻长期使用后,特性也会变化。结果,桥路平衡电阻失去了对半导     

射频对电火工品的影响及防护措施

文章对电火工品(EED)的射频耦合路径进行了分析,根据天线理论对射频的耦合特性进行理论计算,将计算结果同试验结果进行了比较,说明武器中应用的电火工品在强电磁射频环境下能够受到危害,同时提出了几种有效防护射频危害的方法.     

镍铬-镍硅热电偶老化失效机理初探

就镍铬-镍硅热电偶在大气中1200℃、605h老化失效试验后的氧化情况进行了分析,对氧化过程进行了探讨,结果表明镍硅合金中的硅和镍的优先氧化是引起镍铬-镍硅热电偶热电动势超差的主要原因。     

配热电阻数显仪表的六端电桥电阻的调整

本文介绍了配热电阻数显仪表中六端电桥的常见误差，分析了单点超差和双点超差与电桥各电阻阻值的关系，进而提出以调整相应电阻阻值消除超差的有效方法。     

Failure analysis method to study solder wicking phenomena in modern microelectronic devices

Many plastic encapsulated multi chip module (MCM) devices are prone to delamination due to lack of adherence between the materials that compose the package. The problem can get worse if there is a moisture sensitivity level (MSL) violation. When there is a poor adherence between ceramic passive components like capacitors or resistors and plastic molding compound delamination can occur on top of the components and a path for solder to flow is created. When a delaminated MCM device is submitted to lead free solder reflow above 250 °C peak temperature, the solder contained inside the package can flow through any void or empty space inside the package. This could affect the performance and reliability of the system. Package level reliability tests can be performed to assure that good adherence of the materials that compose the device package exists. A solder heat resistance (SHR) test is commonly performed to validate that a specific device package can withstand the worst moisture–solder reflow scenarios during the final assembly process. In this work experiments were carried out in order to replicate the solder wicking failure mechanism. Two groups of MCM, 77 devices were subjected to SHR test using moisture sensitivity level MSL2A and MSL3 conditions and a 250 °C peak reflow temperature. The electrical failures that occurred after the experiment were analyzed according to a specific failure analysis method in order to detect the failure mechanism. Special attention was paid on leakage current and continuity failures since these are the main failure modes associated with solder wicking on ceramic passive components assembled in MCM devices.     

A review of interconnect materials used in emerging memory device packaging: first- and second-level interconnect materials

The main motivation of this review is to study the evolution of first and second level of interconnect materials used in memory device semiconductor packaging. Evolutions of bonding wires from gold (Au) to silver (Ag) or copper (Cu) have been reported and studied in previous literatures for low-cost solution, but Au wire still gives highest rating in terms of the performance of temperature humidity test, high temperature storage, and bond-ability, etc. However, a new bonding wire material, Au-coated Ag, is recently developed to be an alternative solution which gives comparable performance, but lower cost compared to Au wire. In the first section of the article, the influence of a variety of factors were reviewed, which includes reliability performance and interfacial reaction that determines the performance of Au-coated Ag to reach for developing high reliability of bonded devices. With respect to second-level interconnects, SAC305 and SAC302 solder alloys give a balance performance between temperature cycling testing and drop testing, which are widely used in many field applications, such as mobile, consumer and computer. SAC405 and LF35 are developed for specific requirements such as SAC405 owns better temperature cycling performance, whereas LF35 gives excellent drop performance compared to SAC305 or SAC302. However, with market demands on automotive electronics get strong in recent years, solder joint reliability is being reviewed and discussed, especially in temperature cycling performance. Typical solder alloys on Ni/Au surface finish were not designed for automotive application to fulfill the requirement of board level reliability. Hence, newly developed solder alloys with Sn/Ag/Cu/Bi/Ni elements and Cu-OSP substrate surface finishes will be reviewed in the second section of the article.

     

微细丝与异质材料多股导线平行电极电阻钎焊装置设计及焊接工艺研究

目的 开发用于微细直径丝材与不等直径异质多股线精密连接的装置,并对其进行优化设计。方法 采用直径为0.2 mm的镍丝与不等直径铜质多股线为焊材,采用石墨电极,设计了以上电极为凸台、下电极为凹槽的方案,但考虑到凸台电极容易发生损耗,将上电极优化为平行电极,并结合装置特点设计了专用工装夹具。在此基础上进行焊接试验;分别选用直接微电阻钎焊工艺与平行电极微电阻钎焊工艺对镍丝与铜质多股线进行焊接试验,对比研究了先上电极优化后微电阻钎焊、先压方后微电阻钎焊、直接微电阻钎焊、平行电极微电阻钎焊工艺所得焊接接头的成形情况,探究不同工艺与焊接参数对接头质量的影响机制,并获得最优工艺方案;对不同工艺及焊接参数下所得的焊接接头进行拉剪力测试与微观组织分析,对不同条件下接头的拉剪力与微观组织进行分析比较,并对拉剪性能较好的平行电极微电阻钎焊接头进行振动测试,研究其抗振性能。结果 采用先上电极优化后微电阻钎焊工艺得到的焊接接头的平均拉剪力为21.04 N;采用先压方后微电阻钎焊工艺得到的焊接接头的平均拉剪力为15.04 N;采用直接微电阻钎焊工艺得到的焊接接头的最大拉剪力为22.3 N,其钎料并未完全包裹高温导线,成形差;采用平行电极微电阻钎焊工艺得到的焊接接头的平均拉剪力为24.8 N,其接头连接稳定,最大直径均不超过0.8 mm,且抗振性能良好。结论 设计并优化得到的平行上电极能够有效减少电极损耗,通过比较各工艺接头可知,先压方后平行电极微电阻钎焊为最佳的焊接方案,焊点直径稳定,接头质量良好,可以实现传感器引脚线与多股高温导线的高质量、精密、可靠焊接。     

Room temperature oxidation of eraser head leads

Tin coated brass lead wires for eraser heads oxidized during room temperature storage. The oxidized wires were difficult to solder because the wire surface was no longer readily wet by molten solder. Analysis of oxidized and nonoxidized eraser head leads demonstrated that the tendency for unacceptable oxidation was due to porosity in the tin coating, sulfur contamination, and selective oxidization of zinc from the brass wire. Increasing the thickness of the tin coating eliminated the unacceptable oxidation.     

板级封装焊点的振动冲击加速失效方法研究

设计了一种针对板级微电子封装微焊点的振动冲击加速失效试验。对线路板施加定频正弦振动载荷,测量线路板应变值以标定PCB板级载荷水平,采用高速数据采集系统记录了振动载荷作用下的微焊点失效动态过程。结果表明：通过调节振动条件,采用板级振动试验可以获得近似板级跌落冲击试验的峰值形变,其峰值载荷作用频次高于跌落冲击试验;失效数据监测结果显示焊点在振动冲击试验中表现为疲劳失效特征。本加速失效试验在保持焊点失效特征的同时提高了试验效率,可作为跌落冲击条件下微焊点板级可靠性评估的备选试验方案。     

Comparison of drop performance between the Sn37Pb and the Sn3.8Ag0.7Cu solder joints subjected to drop test

This study was concerned with the drop performance between the Sn37Pb and the Sn3.8Ag0.7Cu (wt. %) solder joints when the specimens were subjected to drop test after soldering process. The U-notch butt-jointed specimen was adopted and a lab-designed drop tester was employed. Meanwhile, the electrical resistance values of two kinds of solder joints were measured and recorded after certain drop tests, and finally drop number versus resistance curves were plotted and compared. From the resistance variation with the drop number, it was observed that the Sn37Pb joints presented significantly higher drop performance than the Sn3.8Ag0.7Cu ones. For the Sn3.8Ag0.7Cu specimens, the average drop number before failure was approximately 15-18 and then the resistance values sharply increased. However, the average drop number of the Sn37Pb joints was over 110 and the increasing rate of the electrical resistance was smooth, which is consistent with the results of the board-level drop test. Moreover, one specimen of each kind was picked out and the microstructural observation was carried out to investigate the joint deformation behavior in the dynamic load. It was obvious that the plastic deformation capacity of the Sn37Pb joints was remarkably higher than the one of the Sn3.8Ag0.7Cu joints, proving that most of SnAgCu-based solders presented low deformation compatibility and low energy absorption.     

Reliability assessment and mechanical characterization of Cu and Au ball bonds in BGA package

Extended reliability and mechanical characterisation of Au and Pd-coated Cu (Cu) ball bonds are useful technical information for Au and Cu wire deployment in semiconductor device packaging. This paper discusses the influence of wire type on the package reliability and mechanical performance after several component reliability stress tests. Failure analysis has been conducted to identify the associated failure mechanisms of Au and Cu ball bonds after reliability tests. Wire pull strength and ball bond shear (with its break modes) of both wire types are investigated after unbiased highly accelerated temperature and humidity stress test (UHAST), temperature cycling (TC) and high temperature storage life test (HTSL) at various aging temperatures. Reliability Weibull plots have been plotted for each reliability stresses. Obviously Au ball bond is found with longer time-to-failure in Unbiased HAST stress compare to Cu ball bonds. Cu wire exhibits equivalent package and or better reliability margin compare to Au ball bonds in TC and HTSL tests. Failure mechanisms of UHAST and HTSL have been proposed and its mean-time-to failure (t₅₀), characteristics life (t_63.2, η) and shape parameter (ß) have been discussed in this paper.     

Investigation on high temperature mechanical fatigue failure behavior of SnAgCu/Cu solder joint

In this paper, high temperature mechanical fatigue tests on SnAgCu/Cu solder joints were carried out under three test temperatures (100, 125, 150 °C). Failure mechanism was analyzed through observation of micro-crack evolution and fracture morphology. The results show that the deformation curve of solder joint under high temperature mechanical fatigue tests can be divided into three stages: strain hardening stage, stable deformation stage and accelerated failure stage, which is similar to the curve under creep test condition. In addition, the cyclic life decreases rapidly with increasing temperature. Deformation field in the solder joint is non-uniform and shear strain concentration occurs in solder close to the intermetallic compound (IMC) layer. Micro-crack initiates at the corner of the solder joint and then tend to propagate along interface between Cu substrate and solder. The fracture morphology under three temperatures all exhibits ductile fracture mode and the failure path transforms from cutting through the top of Cu₆Sn₅ to propagation in solder matrix close to IMC layer with increasing temperature.     

环氧浇注干式变压器开裂失效分析

某环氧浇注干式变压器在使用过程中发生开裂失效,为查明开裂原因,笔者对其进行了磁感应强度测试、导线电阻测试和x射线扫描分析。结果表明：该变压器开裂是由于其固定板设计不合理,未进行圆弧处理,灌封时尖角处应力集中,导致变压器在进行高、低温试验时于尖角处产生裂纹,最终引起变压器开裂并伴有黑色物质流出。     

Temperature measurement at flip chip solder joint during electromigration test

Measuring the real temperature of a flip chip solder joint during an electromigration test has been a problem because of its small size and the local Joule heating due to a large applied current. A unique method that employs the electrical resistance change in the junction line between two solder joints was introduced to determine the temperature of the solder joint. The change in resistance was converted into temperature using a thermal coefficient of resistance of the junction line. The method accurately measured temperatures of the solder joint within 2 K until the solder joint resistance change ratio reached 100% due to growth of an electromigration void.