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采用双面贴装回流焊工艺在FR4基板表面贴装Sn3.0Ag0.5Cu(SnAgCn)无铅焊点BGA器件,通过对热应力加速实验中失效的SnAgCu无铅BGA焊点的显微结构分析和力学性能检测,研究双面贴装BGA器件的电路板出现互连焊点单面失效问题的原因,单面互连焊点失效主要是由于回流焊热处理工艺引起的.多次热处理过程中,NiSnP层中形成的大量空洞是导致焊点沿(Cu,Ni)6Sn5金属间化合物层和Ni(P)镀层产生断裂失效的主要因素.改变回流焊工艺是抑制双面贴装BGA器件的印制电路板出现互连焊点单面失效问题的关键. 相似文献
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目前厂内氮气炉的焊接气氛均是通过自带的氧浓度仪表进行控制.随着专业在线测试回流焊炉内氧浓度设备的产生及应用,发现炉内实际情况与回流焊炉仪表的显示值相差悬殊.研究分别选择氧气体积分数3×10-3、7×10-3、10×10-3、15×10-3、45×10-3、80×10-3以及空气进行回流焊接,对比焊点的外观、气泡率、焊点强度以及界面IMC,最后发现不同氧气体积分数气氛对焊接品质无明显的影响. 相似文献
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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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加热因子——回流焊曲线的量化参数 总被引:2,自引:0,他引:2
本介绍了一种用于回流焊曲线优化的参数“加热因子”。加热因子的大小反映了焊点中IMC的厚度,极大的影响着焊点的可靠性,通过对加热因子的调整可以实现回流焊曲线优化,提高焊点的可靠性。 相似文献
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电迁移对Sn3.0Ag0.5Cu无铅焊点剪切强度的影响 总被引:1,自引:1,他引:0
通过热风回流焊制备了Cu/Sn3.0Ag0.5Cu/Cu对接互连焊点,测试了未通电及6.5 A直流电下通电36 h和48 h后焊点的剪切强度.结果表明,电迁移显著地降低了焊点的剪切强度,电迁移36 h使剪切抗力降低约30%,电迁移48 h降低约50%.SEM观察断口和界面形貌表明,界面金属间化合物增厚使断裂由韧性向脆性... 相似文献
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焊点在热循环服役条件下的力学行为分析是研究互连焊点失效机制的可行手段.采用MSC.MARC2000/MENTAT2000建立波峰焊焊点可靠性分析有限元模型,利用有限元计算软件Surface Evolver来对模型进行求解,研究三维空间中由重力、表面张力和其它形式的外力作用下的液体表面的成型问题.通过对典型插装元器件波峰焊焊点建立有限元分析的力学模型和在热循环载荷下应力应变过程,分析焊点内部力学参量和应力场的分布特征,结合通孔波峰焊点的热冲击可靠性测试结果,以此研究焊点失效机制. 相似文献
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The work presented in this paper focuses on the effect of reflow process on the contact resistance and reliability of anisotropic conductive film (ACF) interconnection. The contact resistance of ACF interconnection increases after reflow process due to the decrease in contact area of the conducting particles between the mating I/O pads. However, the relationship between the contact resistance and bonding parameters of the ACF interconnection with reflow treatment follows the similar trend to that of the as-bonded (i.e. without reflow) ACF interconnection. The contact resistance increases as the peak temperature of reflow profile increases. Nearly 40% of the joints were found to be open after reflow with 260 °C peak temperature. During the reflow process, the entrapped (between the chip and substrate) adhesive matrix tries to expand much more than the tiny conductive particles because of the higher coefficient of thermal expansion, the induced thermal stress will try to lift the bump from the pad and decrease the contact area of the conductive path and eventually, leading to a complete loss of electrical contact. In addition, the environmental effect on contact resistance such as high temperature/humidity aging test was also investigated. Compared with the ACF interconnections with Ni/Au bump, higher thermal stress in the Z-direction is accumulated in the ACF interconnections with Au bump during the reflow process owing to the higher bump height, thus greater loss of contact area between the particles and I/O pads leads to an increase of contact resistance and poorer reliability after reflow. 相似文献
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Andrew Farris Albert Liddicoat Nicholas Vickers Dan Maslyk Jasbir Bath David A. Geiger 《Microelectronics Reliability》2009,49(7):761-770
This paper presents the drop test reliability results for edge-bonded 0.5 mm pitch lead-free chip scale packages (CSPs) on a standard JEDEC drop reliability test board. The test boards were subjected to drop tests at several impact pulses, including a peak acceleration of 900 Gs with a pulse duration of 0.7 ms, a peak acceleration of 1500 Gs with a pulse duration of 0.5 ms, and a peak acceleration of 2900 Gs with a pulse duration of 0.3 ms. A high-speed dynamic resistance measurement system was used to monitor the failure of the solder joints. Two edge-bond materials used in this study were a UV-cured acrylic and a thermal-cured epoxy material. Tests were conducted on CSPs with edge-bond materials and CSPs without edge bonding. Statistics of the number of drops-to-failure for the 15 component locations on each test board are reported. The test results show that the drop test performance of edge-bonded CSPs is five to eight times better than the CSPs without edge bonding. Failure analysis was performed using dye-penetrant and scanning electron microscopy (SEM) methods. The most common failure mode observed is pad lift causing trace breakage. Solder crack and pad lift failure locations are characterized with the dye-penetrant method and optical microscopy. 相似文献
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Zama S. Baldwin D.F. Hikami T. Murata H. 《Electronics Packaging Manufacturing, IEEE Transactions on》2001,24(4):261-268
This research focuses on flip chip interconnect systems consisting of wire stud bumps and solder alloy interconnects. Conventional gold (Au) wire stud bumps and new copper (Cu) wire stud bumps were formed on the chip by wire stud bumping. Cu wire studs were bumped by controlling the ramp rate of ultrasonic power to eliminate the occurrence of under-pad chip cracks that tend to occur with high strength bonding wire. Lead free 96Sn3.5Ag0.5Cu (SnAgCu) alloy was used to interconnect the wire studs and printed circuit board. A comparison was made with conventional eutectic 63Sn37Pb (SnPb) alloy and 60In40Pb (InPb) alloy. Test vehicles were assembled with two different direct chip attachment (DCA) processes. When the basic reflow assembly using a conventional pick and place machine and convection reflow was used, 30% of the lead free test vehicles exhibited process defects. Other lead free test vehicles failed quickly in thermal shock testing. Applying the basic reflow assembly process is detrimental for the SnAgCu test vehicles. On the other hand, when compression bonding assembly was performed using a high accuracy flip chip bonder, the lead free test vehicles exhibited no process defects and the thermal shock reliability improved. Cu stud-SnAgCu test vehicles (Cu-SnAgCu) in particular showed longer mean time to failure, 2269 cycles for the B stage process and 3237 cycles for high temperature bonding. The C-SAM and cross section analysis of the Cu stud bump assemblies indicated less delamination in thermal shock testing and significantly less Cu diffusion into the solder compared to Au stud bumped test vehicles. The Cu stud-SnAgCu systems form stable interconnects when assembled using a compression bonding process. Moreover, Cu wire stud bumping offers an acceptable solution for lead free assembly 相似文献
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Guoyun Tian Yueli Liu Johnson R.W. Lall P. Palmer M. Islam M.N. Crane L. 《Electronics Packaging Manufacturing, IEEE Transactions on》2005,28(3):231-240
The use of chip-scale packages (CSPs) has expanded rapidly, particularly in portable electronic products. Many CSP designs will meet the thermal cycle or thermal shock requirements for these applications. However, mechanical shock (drop) and bending requirements often necessitate the use of underfills to increase the mechanical strength of the CSP-to-board connection. Capillary flow underfills processed after reflow provide the most common solution to improving mechanical reliability. However, capillary underfill dispense, flow, and cure steps and the associated equipment add cost and complexity to the assembly process. Corner bonding provides an alternate approach. Dots of underfill are dispensed at the four corners of the CSP site after solder paste print but before CSP placement. During reflow, the underfill cures, providing mechanical coupling between the CSP and the board at the corners of the CSP. Since only small areas of underfill are used, board dehydration is not required. This paper examines the manufacturing process for corner bonding including dispense volume, CSP placement, and reflow. Drop test results are then presented. A conventional, capillary process was used for comparison of drop test results. Test results with corner bonding were intermediate between complete capillary underfill and nonunderfilled CSPs. Finite-element modeling results for the drop test are also included. 相似文献
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The flip chip bonding process using anisotropic conductive adhesives (ACA) and the consequent joint reliability were studied. The substrates used were rigid FR-4 boards, which are interesting due to their low cost and wide range of applications. The problems associated with the technique are discussed in this paper from the reliability point of view. Also, some aspects concerning production are introduced.The reliability of the joints was studied by accelerated environmental tests. A temperature cycling test was performed between temperatures −40 and +125 °C. Constant humidity testing was conducted at 85 °C and RH85%. In addition, reflow aging tests were performed using a conventional Sn/Pb reflow profile. For reducing the bonding cycle time, a two-stage curing process was used, which also utilizes the reflow process.The results show that the three bonding parameters, temperature, time, and pressure, all affect joint reliability. Most detrimental, however, seems to be reflow treatment performed after bonding. Most failures occurred only very briefly during the temperature cycling at the moment the temperature changed, while the joints were still conducting at both temperature extremes. However, a different failure mechanism caused a different kind of behavior during temperature cycling. The relationship between the failure modes and the failure mechanisms was studied using a scanning electron microscopy. 相似文献
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双面压敏胶带在柔性电路板组装行业有着广泛和大量的应用.综述了柔性电路板行业对压敏胶带的常规性能要求,从被粘材质和胶带种类以及测试要求等方面逐一说明,提供了使用指南.此外,还特别介绍了耐高温丙烯酸酯压敏胶带在柔性电路板行业的应用和性能表现,适合于需要在柔性电路板回流焊工艺前进行表面粘贴的应用,也可用于其他有耐高温性能要求的粘接应用. 相似文献
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《Advanced Packaging, IEEE Transactions on》2008,31(3):442-446
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In this paper, the results of reliability testing (life testing at 125°C for 2000 h) and failure analysis of polysilicon thin film resistors with irreversible resistance transition are presented and discussed. The results of the life test show that electrical parameters of the polysilicon resistors (resistance before transition, transition voltage and resistance after transition) are satisfactorily stable during the life test. Also, calculated values of the mean time before failure (MTBF) and the mean time to failure (MTTF) on the basis of the life test data confirm that the polysilicon resistors have a satisfactory level of reliability for long-term applications. Finally, the results of failure analysis show that typical failure modes of the polysilicon resistors are open, while the responsible failure mechanism is electromigration of aluminum during the life test at the contact between the aluminum line and polysilicon film. 相似文献
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研究了倒装芯片中UBM制备和焊球回流工艺流程。通过改变阻挡层Ni和浸润层Cu的厚度,结合推拉力测试实验,探究了SnAgCu焊点剪切强度的变化规律。研究结果表明,UBM中阻挡层Ni对SnAgCu焊点的力学性能影响最大,而浸润层Cu厚度的增加也能提高SnAgCu焊点的力学性能。进一步对推拉力实验后的焊点形貌进行了SEM观察和EDS分析,得到了焊盘剥离、脆性断裂、焊球剥离、韧性断裂四种不同的焊点失效形式,代表着不同的回流质量,而回流质量主要由UBM的成分和厚度决定。研究结果为倒装焊工艺的优化提供了理论指导。 相似文献