共查询到18条相似文献,搜索用时 250 毫秒
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为研究振动载荷下板级微互连焊点的退化规律,设计了等幅定频正弦振动试验。采集焊点两端的电压信号,利用退化数据的统计特征对焊点失效过程的电压信号进行阶段划分和趋势拟合。结果表明,焊点的退化数据表征具有健康、轻度失效、重度失效和完全断裂四个阶段。轻度失效和重度失效阶段具有相似的表征形式,均可以分为陡变、缓变和平坦三个区间。采用监测数据计算样本的均值方差,建立了单调递增的退化特征模型。通过数据拟合选取误差较低的表征量,实现了焊点的健康状况评估和失效预警。 相似文献
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针对互连焊点在长期应力作用下的蠕变失效,探讨了焊点阻值退化的一般性趋势,在此基础上提出了一种基于电阻电桥原理的焊点故障监测和预警电路设计方案,并基于电子产品可靠性保障工程应用,讨论了电路板级互连焊点故障监测和预警电路的实现路径的方法。嵌入式监测电路在电阻缓慢退化阶段和快速退化阶段设置合理的监测起始和终止点,适合对服役中的焊点健康状况进行实时监测和评估。同时,电路具有预警功能,在焊点电性能退化的初期发出预警,并实时采集焊点阻值数据用于焊点剩余寿命的预测,以实现焊点退化的及时预警和退化焊点剩余寿命的预计。 相似文献
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空调控制器主板在售后使用1-3年后出现的报PL故障,经过失效品分析及大量数据统计,大部分电阻失效集中在控制器外电路的直流母线电压检测电路片状电阻位置,电阻表现为值大、开路失效,通过对售后返回大量的电阻失效分析和电阻硫化实验验证,采用扫描电镜、能谱分析等手段研究了厚膜片式电阻器的硫化现象和失效机理.分析研究结果显示,片状电阻端电极和二次保护包覆层之间存在缝隙,空气中的硫化物通过灌封硅胶吸附进入到片状电阻内电极,导致内电极涂覆银层的银被硫化,生成电导率低的硫化银,使电阻的阻值变大甚至呈现开路状态.经大量的方案分析验证最终确定从器件本身提高器件的应用可靠性的可行方案,有效解决了电阻硫化失效问题. 相似文献
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基于正交试验法研究不同温度与振动耦合条件下的板级焊点失效行为与模式,采用L9(34)混合水平正交表设计了不同温度(T)、加速度功率谱密度(PSD)与频率(V)条件下的加速寿命试验,结果表明三者对焊点可靠性影响程度为T>PSD>V,且温度是影响焊点失效模式的主要因素,随温度的升高,焊点裂纹逐渐从近封装侧的界面金属化合物(IMC)层向钎体内部扩展,焊点失效模式从脆性断裂向韧性断裂演化.基于焊点失效数据分析,发现焊点疲劳寿命对数值与PCB板背侧最大应变范围存在关联关系,并采用多项式拟合的方法建立了焊点疲劳寿命模型,拟合结果显示,该模型能较好的评估温度与振动耦合条件下的焊点寿命,预测精度较高. 相似文献
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焊点的失效模式与分析 总被引:2,自引:0,他引:2
焊点疲劳寿命通常是通过电子组件进行温度循环加速试验来确定.针对典型元器件进行温度循环试验,在不同的循环周期检查焊点的开裂情况,并采用金相分析观察焊点的显微组织,分析焊点在温度循环条件下的失效模式,为改进工艺参数提供依据. 相似文献
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将功率循环方法应用于大功率LED焊料层的可靠性研究,对比分析了在650 mA,675 mA和700 mA电流条件下大功率LED焊料层的热阻退化情况。实验结果表明,循环达到一定次数,大功率LED热阻才开始退化,并呈线性增加,从而引起光通量下降;另外,失效循环次数与电流值之间呈线性关系,并外推出正常工作条件下焊料层寿命为90 968次。对样品进行了超声波检测(C-SAM),发现老化后LED焊料层有空洞形成,这说明空洞是引起热阻升高的主要原因。 相似文献
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《Components and Packaging Technologies, IEEE Transactions on》2006,29(3):449-456
Board level solder joint reliability performance during drop test is a critical concern to semiconductor and electronic product manufacturers. A new JEDEC standard for board level drop test of handheld electronic products was just released to specify the drop test procedure and conditions. However, there is no detailed information stated on dynamic responses of printed circuit board (PCB) and solder joints which are closely related to stress and strain of solder joints that affect the solder joint reliability, nor there is any simulation technique which provides good correlation with experimental measurements of dynamic responses of PCB and the resulting solder joint reliability during the entire drop impact process. In this paper, comprehensive dynamic responses of PCB and solder joints, e.g., acceleration, strains, and resistance, are measured and analyzed with a multichannel real-time electrical monitoring system, and simulated with a novel input acceleration (Input-G) method. The solder joint failure process, i.e., crack initiation, propagation, and opening, is well understood from the behavior of dynamic resistance. It is found experimentally and numerically that the mechanical shock causes multiple PCB bending or vibration which induces the solder joint fatigue failure. It is proven that the peeling stress of the critical solder joint is the dominant failure indicator by simulation, which correlates well with the observations and assumptions by experiment. Coincidence of cyclic change among dynamic resistance of solder joints, dynamic strains of PCB, and the peeling stress of the critical solder joints indicates that the solder joint crack opens and closes when the PCB bends down and up, and the critical solder joint failure is induced by cyclic peeling stress. The failure mode and location of critical solder balls predicted by modeling correlate well with experimental observation by cross section and dye penetration tests. 相似文献
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《Microelectronics Reliability》2014,54(12):2922-2928
In this study, low-cycle fatigue test was conducted for a lead-free solder joint at two test temperatures (348 K, 398 K) and three strain amplitudes (3%, 4%, and 8%). Fatigue failure behavior was analyzed and the fatigue life was evaluated using the Coffin–Manson relationship and Morrow energy-based model. The results show that the maximum load gradually drops with increasing the number of loading cycles. When the strain range or temperature is low, the maximum load drop curve can be divided into three stages. Then, it degrades into a linear stage with increasing the strain range or temperature. Both the softening of solder and the reduction of effective load-bearing area are responsible for the maximum load drop depending on the test condition. Fatigue crack initiates at the corner of the solder joint and propagates along the strain concentrated zone. Spacing distance between fatigue striations is enlarged with increasing the temperature in accordance with the degradation of fatigue resistance. In addition, both the Coffin–Manson model and Morrow energy-based model can be used to evaluate the fatigue life of solder joint under high temperature. The fatigue ductility exponent α in Coffin–Manson model and the fatigue ductility coefficient C in Morrow model are dependent on temperature, whereas other parameters in these two models keep stable under different temperature. 相似文献
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Poon N.M. Wu C.M.L. Lai J.K.L. Chan Y.C. 《Advanced Packaging, IEEE Transactions on》2000,23(4):708-714
In this study, two lead-free solder alloys, namely 50 tin-50 bismuth (Sn-Bi) and 96.5 tin-3.5 silver (Sn-Ag), were studied for their use in surface mount solder joints. They have been considered as potential replacements for 63 tin-37 lead (Sn-Pb) solder. All joints were subjected to various cycles of thermal shock with temperature ranging from -25 to 125/spl deg/C. Shear tests were conducted on joints with and without thermal shock treatment. Another thermal shock cycle (-25 to 85/spl deg/C) was carried out on Sn-Bi solder joints for comparison. Their performance against thermal shock was compared with eutectic Sn-Pb solder by evaluating their residual shear strength and studying their microstructural change. For the Sn-Ag solder, a fine rod-like Ag/sub 3/Sn intermetallic was formed in the solder matrix after the thermal shock. On the other hand, Bi-rich and Sn-rich phases appeared in the Sn-Bi solder after the -25 to 125/spl deg/C thermal shock. Moreover, fine cracks were observed along the Bi-rich grain-like phase boundary. These were not observed in the Sn-Bi solder with the -25 to 85/spl deg/C thermal shock treatment. Voids and cracks were also observed in the joint of Sn-Bi solder alloy after 1000 thermal shock cycles. In addition, the thickness of intermetallic compound (IMC) of three solder alloys gradually grew with the number of thermal shock cycles. These defects reduced the strength of solder joint and led to thermal fatigue failure. In general, the shear strength is found to decrease with increasing number of thermal shock cycles. The Sn-Ag solder was better than the Sn-Bi solder in terms of residual thermal shock shear strength. Sn-Bi solder showed good properties when it was treated with the -25 to 85/spl deg/C thermal shock. It has a strong potential to replace Sn-Pb solder in low temperature applications such as consumer electronics. The Sn-Ag solder is suitable for high temperature applications. 相似文献
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Yoshiharu Kariya Yasunori Hirata Masahisa Otsuka 《Journal of Electronic Materials》1999,28(11):1263-1269
Quad Flat Pack (QFP) Leads/Sn-3.5Ag-X (X=Bi and Cu) joint was thermally cycled between 243 K and 403 K or 273 K and 373 K,
and both metallographic examination and mechanical pull test were performed to evaluate thermal fatigue damage of the joint.
The addition of bismuth drastically degrades the thermal fatigue resistance of Sn-3.5Ag solder. On the other hand, the pull
strength of Sn-3.5Ag-Cu solder joints slightly decreased with increasing number of thermal cycles, though it still remains
higher in comparison to that for conventional Sn-37Pb or bismuth containing solder joint. The behavior observed here reflects
the isothermal fatigue properties of bulk solder, because thermal fatigue crack initiates at the surface of solder fillet
and propagates within the fillet in an early stage of fatigue damage. Furthermore, the lead phases lying at the interface
between lead-frame and bismuth containing solder joint may promote the crack propagation at the interface, resulting in the
extremely low thermal fatigue resistance of the joint. 相似文献
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Solder joint fatigue failure under vibration loading has been a great concern in microelectronic industry. High-cycle fatigue failure of lead-free solder joints has not been adequately addressed, especially under random vibration loading. This study aims to understand the lead-free solder joint behavior of BGA packages under different random vibration loadings. At first, non-contact TV Laser holography technology was adopted to conduct experimental modal analysis of the test vehicle (printed circuit board assembly) in order to understand its dynamic characteristics. Then, its first order natural frequency was used as the center frequency and narrow-band random vibration fatigue tests with different kinds of acceleration power spectral density (PSD) amplitudes were respectively carried out. Electrical continuity through each BGA package is monitored during the vibration event in order to detect the failure of package-to-board interconnects. The typical dynamic voltage histories of failed solder joints were obtained simultaneously. Thirdly, failed solder joints were cross-sectioned and metallurgical analysis was applied to investigate the failure mechanisms of BGA lead-free solder joints under random vibration loading. The results show that the failure mechanisms of BGA lead-free solder joint vary as the acceleration PSD amplitude increases. Solder joint failure locations are changed from the solder bump body of the PCB side to the solder ball neck, finally to the Ni/intermetallic compound (IMC) interface of the package side. The corresponding failure modes are also converted from ductile fracture to brittle fracture with the increase of vibration intensity. 相似文献