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1.
M.B. Small  C.-K. Hu 《Thin solid films》1997,300(1-2):278-283
Modern interconnect structures may be regarded as a large number of basic units: pairs of Al alloy lines at two levels interconnected by vias. Presently as many as six levels of wiring may be used. Generally the vias present barriers to the transport of components of the alloy between levels. While it is recognized that the failure statistics of such structures are different from the conventional test structure, different values of activation energy for failure have been reported. Consequently, different interpretations may be made regarding mechanisms. Simulations are presented to demonstrate that differences between test structures can result in different measurements. It is shown that simple lines, passivated with native oxide, need to be longer than about seven times the critical length and lines terminate in pads at the anode end about four times this length, if measurements of both lifetime and activation energy are to be representative of long lines.  相似文献   

2.
Plastic prestraining was applied to a solder interconnect to introduce internal defects such as dislocations in order to investigate the interaction of dislocations with electromigration damage. Above a critical prestrain, Bi interfacial segregation to the anode, a clear indication of electromigration damage in SnBi solder interconnect, was effectively prevented. Such an inhibiting effect is apparently contrary to the common notion that dislocations often act as fast diffusion paths. It is suggested that the dislocations introduced by plastic prestraining acted as sinks for vacancies in the early stage of the electromigration process, but as the vacancies accumulated at the dislocations, climb of those dislocations prompted recovery of the deformed samples under current stressing, greatly decreasing the density of dislocation and vacancy in the solder, leading to slower diffusion of Bi atoms.  相似文献   

3.
The electromigration performance of the Al-1 per cent Si/TiN/Ti metal scheme is investigated both for contacts and for stripes and compared with the results for the standard Al-1 per cent Si metallization. Statistical extrapolations at the operating conditions for a device have been performed to calculate the useful life of contacts and stripes. The results indicate that the most severe limitation to the interconnection reliability is given by the contacts without the diffusion barrier layer.  相似文献   

4.
In-situ side-view transmission electron microscopy (TEM) observations of electromigration in Al-on-TiN lines with a drift velocity measurement structure have been carried out using an ultrahigh voltage (2 MV) electron microscope. Thick chips as-diced from silicon substrates served as TEM samples. The observations revealed the dynamic behavior of electromigration-induced voids and hillocks during forward and reverse current feeding through the Al lines. The results include vertical growth of voids bounded by faceted Al, refilling of voids, void growth in a hillock upon current reversal, and whisker growth.  相似文献   

5.
The modern tendency for increasing the productivity of microelectronic devices at the expense of the size shrinkage and the development of densely packed multilevel microelectronic structures stipulates the rising concern for the reliability of integrated circuits. The damage of integrated circuits is mainly caused by electromigration in thin-film interconnects. The current-induced redistribution of vacancies and the action of vacancy sinks/sources lead to heterogeneous volume deformations, which, in turn, cause the rise of mechanical stresses. The interconnect failure is initiated by the nucleation of voids taking place on the crystalline structure heterogeneities like triple points, inclusions, etc. or in the plug region of multilevel metallizations. In the latter case the interconnect damage is also caused by the edge depletion. Mechanical stresses induced by electromigration strongly influence the nucleation process. In the present work we propose a general 3D model for electromigration and the rise of mechanical stresses in a passivated aluminum interconnect. A system of differential equations describing electromigration and induced deformation of an interconnect is derived. We also propose a kinetic model for the void nucleation, elaborated on the basis of the classical theory of the new phase nucleation. Integral equations for the time to the void nucleation are deduced. Based on these models numerical calculations for the void formation in a triple point of the interconnect crystalline structure and for both failure mechanisms in the plug region have been carried out. The times to nucleation and characteristic sizes of voids are calculated as functions of temperature and electric current density. The results obtained agree well with experimental data.  相似文献   

6.
The diffusion behavior of Cu and Ni atoms undergoing liquidesolid electromigration(L-S EM) was investigated using Cu/Sn/Ni interconnects under a current density of 5.0 103A/cm2 at 250℃. The flowing direction of electrons significantly influences the cross-solder interaction of Cu and Ni atoms, i.e., under downwind diffusion, both Cu and Ni atoms can diffuse to the opposite interfaces; while under upwind diffusion,Cu atoms but not Ni atoms can diffuse to the opposite interface. When electrons flow from the Cu to the Ni, only Cu atoms diffuse to the opposite anode Ni interface, resulting in the transformation of interfacial intermetallic compound(IMC) from Ni3Sn4into(Cu,Ni)6Sn5and further into [(Cu,Ni)6Sn5t Cu6Sn5], while no Ni atoms diffuse to the opposite cathode Cu interface and thus the interfacial Cu6Sn5 remained.When electrons flow from the Ni to the Cu, both Cu and Ni atoms diffuse to the opposite interfaces,resulting in the interfacial IMC transformation from initial Cu6Sn5into(Cu,Ni)6Sn5and further into[(Cu,Ni)6Sn5t(Ni,Cu)3Sn4] at the anode Cu interface while that from initial Ni3Sn4into(Cu,Ni)6Sn5and further into(Ni,Cu)3Sn4at the cathode Ni interface. It is more damaging with electrons flowing from the Cu to the Ni than the other way.  相似文献   

7.
The in situ method to study accelerated ageing of electronic interconnections under current stress has been applied to (a) Au ball bonds on A11% Si metallization, and (b) thin aluminium tracks. For the Au ball bonds, it has been shown that direct current stresses above 108 Am?2 cause electromigration effects at the Au-Al interface, and that the ageing behaviour depends on the direction of the applied direct current stress. It was also shown that the addition of 1 per cent Cu to the metallization strongly retards void formation, and hence open contact failure. For the thin aluminium tracks, it has been shown that the early stage of electromigration, which can be studied accurately with the in situ technique, is closely related to the stress relaxation within the track. It is therefore concluded that the kinetics of electromigration can only be described if the kinetics of stress relaxation are well understood.  相似文献   

8.
电镀氢脆故障及应对措施   总被引:2,自引:0,他引:2  
李金桂 《材料保护》2006,39(8):51-53
电镀过程中作为阴极的被镀零件在获得镀层的同时在零件金属内部也渗入了氢,如果该零件金属对氢脆敏感、又有拉应力存在时便可能发生氢脆,使零件断裂,甚至诱发事故.介绍了几例典型的氢脆故障,结合实例分析指出,渗入金属内部的氢是可逆氢,可以通过加热烘烤排出,以避免事故发生.  相似文献   

9.
In this study, we introduce reliability models for a device with two dependent failure processes: soft failure due to degradation and hard failure due to random shocks, by considering the declining hard failure threshold according to changes in degradation. Owing to the nature of degradation for complex devices such as microelectromechanical systems, a degraded system is more vulnerable to force and stress during operation. We address two different scenarios of the changing hard failure threshold due to changes in degradation. In Case 1, the initial hard failure threshold value reduces to a lower level as soon as the overall degradation reaches a critical value. In Case 2, the hard failure threshold decreases gradually and the amount of reduction is proportional to the change in degradation. A condition‐based maintenance model derived from a failure limit policy is presented to ensure that a device is functioning under a certain level of degradation. Finally, numerical examples are illustrated to explain the developed reliability and maintenance models, along with sensitivity analysis. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

10.
利用数值方法研究了以P3HT∶PCBM为活性材料的本体异质结有机太阳能电池的短路电流密度与带隙宽度、活性层厚度以及温度的关系。结果表明:短路电流密度随带隙宽度的增大呈线性增大;随活性层厚度的增加呈抛物线分布,在160nm附近短路电流密度有最大值;随温度升高呈线性增大趋势。  相似文献   

11.
The influence of electric current on Kirkendall diffusion in Zn/Cu couples was investigated. Under the action of different electric currents, the Zn/Cu diffusion couples were annealed at 785℃ for different holding time. The experimental results show that the displacement of the Kirkendall plane increases with increasing holding time. However, the displacement of the Kirkendall plane with electric current is larger than that without electric current. The relationship between the displacement of the Kirkendall plane and the holding time is changed under the action of electric current. The likely reason for the electric current enhancing effect is the energy transfer from electron to jumping atom, increasing the integrated diffusion coefficient, which leads to the increase in the velocity of Kirkendall plane.  相似文献   

12.
赵卫民  王勇  薛锦  吴开源 《材料保护》2005,38(4):21-24,31
在碳钢表面制备NiCrBSi耐蚀合金堆焊层,采用腐蚀浸泡试验和交流阻抗法研究了镍基合金层在3.5%NaCl溶液中的腐蚀失效过程.镍基堆焊层具有良好的耐蚀性能,交流阻抗测试过程中利用恒电位极化进行加速腐蚀.结果发现,夹杂物的存在是堆焊层发生局部腐蚀的根本原因,减少夹杂物的数目和减小夹杂物的体积可以有效提高堆焊层的耐蚀性能.堆焊层耐蚀性能稳定,阻抗随腐蚀的进行略有下降,腐蚀体系的等效电路为典型的Randles等效电路.如果堆焊层某些局部区域腐蚀严重,表面有基底露出点,则堆焊层阻抗显著减小,体系的等效电路发生变化,堆焊层与基底间即使没有发生宏观的电偶腐蚀也会失效.自然腐蚀电位测试结果证明,可以通过监测结构件电极电位的变化来判断堆焊层的腐蚀失效情况.  相似文献   

13.
针对某船B10海水管路泄漏问题,通过现场勘验、成分分析、微观组织观察、腐蚀性能评价等方法,分析了管路与海水泵间法兰处腐蚀泄漏的原因。结果表明,B10管成分、微观组织均满足设计技术要求,在海水中的静态腐蚀速率和冲刷腐蚀速率均在正常范围内,B10管泄漏发生的主要原因是该船的防污系统产生的管路内杂散电流所致。  相似文献   

14.
泡沫金属夹层板自冲铆接头的疲劳性能及失效机理   总被引:1,自引:0,他引:1  
刘洋  何晓聪  邢保英  邓聪  张先炼 《材料导报》2018,32(14):2431-2436
对铝合金自冲铆接头及泡沫金属夹层结构自冲铆接头进行疲劳实验,通过三参数经验公式采用S-N曲线拟合法绘制接头的F-N曲线,分析接头的疲劳寿命及泡沫金属夹层对自冲铆接头疲劳性能的影响;采用扫描电子显微镜对接头的疲劳失效断口进行观测,分析其微观失效机理。结果表明:泡沫金属夹层缩短了自冲铆接头的疲劳寿命,不同泡沫金属夹层对自冲铆接头疲劳性能的影响具有差异性,在高疲劳载荷下泡沫铜夹层接头疲劳性能更优。三组接头疲劳失效形式都为下板断裂,在高疲劳载荷下裂纹易在铆扣区域萌生,在中低疲劳载荷下裂纹萌生于下板一侧,沿铆扣区域下侧向板材另一侧扩展。  相似文献   

15.
16.
Bi layer formation in Cu/Sn–58Bi/Cu solder joints was investigated with different current densities and solder thickness. Uniform and continuous Bi layers were formed at the anode interface which indicated that Bi was the main diffusing species migrating from the cathode to the anode. The electromigration force and Joule heating took on the main driving forces for Bi diffusion and migration. In addition, two appearance types of Bi layers, planar-type and groove-type, were found during current stressing. The morphology and thickness of Bi layers were affected by current density and current stressing time.  相似文献   

17.
Failure of Composite Materials   总被引:1,自引:0,他引:1  
I. M. Daniel 《Strain》2007,43(1):4-12
Abstract:  An overview is given of the state of the art of theories and procedures for predicting and analysing failure in composite materials. Of the scores of failure theories available, only those representative of each of the following categories are discussed: limit or noninteractive, interactive, and failure mode-based theories. The validity and applicability of the various theories are evaluated from the point of view of convenience of application and agreement with experimental results. Both lamina and laminate failures are discussed. In the case of ultimate laminate failure, a progressive damage scheme coupled with a failure mode-discriminating criterion is discussed. Special attention is given to textile composites where new three-dimensional experimental results are reported and a new interlaminar failure theory is proposed.  相似文献   

18.
结合一般电子器件失效分析方法,系统地设计了针对已失效LED器件的分析流程,并从封装结构和光、热特性几个方面比较了LED与一般器件失效分析方法的不同之处。通过分析发现了一般分析难以检测到的表面污染物污染、内部芯片断层等失效模式。实验证明,此方法对判断LED失效模式、推测失效机理更加准确,并可以有效地避免一般分析方法中过早的破坏性分析引入的损伤,以及将光电检测中电流和温度应力导致的损伤误判为器件原有失效因素。  相似文献   

19.
Despite significant efforts to fabricate high energy density (ED) lithium (Li) metal anodes, problems such as dendrite formation and the need for excess Li (leading to low N/P ratios) have hampered Li metal battery (LMB) development. Here, the use of germanium (Ge) nanowires (NWs) directly grown on copper (Cu) substrates (Cu-Ge) to induce lithiophilicity and subsequently guide Li ions for uniform Li metal deposition/stripping during electrochemical cycling is reported. The NW morphology along with the formation of the Li15Ge4 phase promotes uniform Li-ion flux and fast charge kinetic, resulting in the Cu-Ge substrate demonstrating low nucleation overpotentials of 10 mV (four times lower than planar Cu) and high Columbic efficiency (CE) efficiency during Li plating/stripping. Within a full-cell configuration, the Cu-Ge@Li – NMC cell delivered a 63.6% weight reduction at the anode level compared to a standard graphite-based anode, with impressive capacity retention and average CE of over 86.5% and 99.2% respectively. The Cu-Ge anodes are also paired with high specific capacity sulfur (S) cathodes, further demonstrating the benefits of developing surface-modified lithiophilic Cu current collectors, which can easily be integrated at the industrial scale.  相似文献   

20.
The behavior of electromigration-induced stress in Al-1.0% Si-0.5% Cu alloy interconnections was investigated in situ by synchrotron radiation at the SPring-8. The electromigration tests were performed as a function of applied current density. When the current was applied to the lines, 111 diffraction peak shifted to lower angle for all measurement points. This indicated that compressive stresses were present at all measurement positions in the lines. When the applied current was stopped, 111 diffraction peak reverted to its initial position for all measurement points. At constant current density, the position of 111 diffraction peak didn't change for any of the measurement positions.  相似文献   

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