共查询到20条相似文献,搜索用时 562 毫秒
1.
板级跌落碰撞下无铅焊点的有限元分析 总被引:1,自引:1,他引:0
为了预测跌落碰撞下球栅阵列(BGA)封装中无铅焊点的失效,采用ABAQUS软件来模拟跌落碰撞过程中焊点的应力分布.首先建立圆形电路板(PCB)组件的有限元模型,接着用模态试验和有限元模拟相结合的方法确定有限元模型的边界条件和PCB的阻尼参数,然后运用ABAQUS有限元软件模拟PCB组件从三种高度下跌落碰撞过程中BGA封装中无铅焊点的拉应力分布.结果表明:封装最外圈四个拐角焊点的拉应力最大,最大拉应力出现在焊点靠近封装的一侧.由此预测最外圈拐角的焊点最易失效,焊点失效的位置在靠近封装一侧. 相似文献
2.
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。 相似文献
3.
通过非接触式激光全息激振方法对试件(电路板组件)进行试验模态分析,了解其动态特性;以其第一阶固有频率作为中心频率,分别进行了三种不同加速度功率谱密度幅值的窄带随机振动疲劳试验,并对失效焊点进行金相剖面分析,探究球栅阵列(BGA)无铅焊点在随机振动载荷下的失效机理。结果表明,三种加速度功率谱密度幅值的随机振动试验中BGA无铅焊点的失效机理不尽相同,随着功率谱密度幅值增加,焊点失效位置由靠近电路板(PCB)一侧向靠近封装一侧转变,分别是靠近PCB一侧的焊球体,焊点颈部以及靠近封装一侧的Ni/金属间化合物(IMC)界面处,相应的失效模式由疲劳断裂转为脆性断裂 相似文献
4.
焊点高度和焊盘尺寸相同情况下,分析焊点形状(桶形、柱形、沙漏形)对BGA封装在板级跌落冲击载荷下可靠性的影响。根据不同焊点形状建立3种3D有限元模型,采用Input-G方法将加速度曲线作为数值模型的载荷输入,对BGA封装件在板级跌落冲击载荷下的可靠性进行分析。结果表明:在跌落冲击过程中,在0.1ms左右PCB板出现最大弯曲变形;焊点形状对BGA封装件在跌落冲击过程中的可靠性有较大的影响;以最大剥离应力作为失效准则对三种焊点进行寿命预测, 沙漏形焊点的平均碰撞寿命值最大,其次是柱形焊点,桶形焊点最小,表明沙漏形焊点在跌落测试中表现出较好的抗跌落碰撞性能。 相似文献
5.
文中进行了三组跌落高度下的焊点疲劳寿命试验,采用比例风险模型(PHM)分析跌落高度对焊点寿命分布的影响。PHM模型估计得到的焊点寿命期望(MTTF)及寿命失效概率密度与实验数据都能够较好的吻合,验证了模型的有效性。且由焊点跌落MTTF值随高度变化曲线可看出,当跌落高度略大于0.6m时焊点MTTF值都小于10次,表明无铅焊点对冲击载荷非常敏感。最后用估计得到的寿命期望结合Miner准则得到板极无铅焊点跌落寿命损伤累积模型。 相似文献
6.
目的 为了评估就地化保护装置跌落冲击载荷下的失效情况。方法 基于显式动力学理论,采用有限元法对就地化保护装置进行跌落冲击的建模仿真。分析PCB板变形与焊点失效之间的关系,探讨元件封装方式对产品抗跌落冲击性能的影响,提出以Von Mises准则得到的焊点最大应力联合跌落寿命模型,进行元件封装可靠性评估的分析方法。针对元件不同封装方式的装置进行跌落验证试验。结果 就地化保护装置跌落冲击仿真结果与试验结果基本吻合。结论 验证了评估元件封装失效分析方法的准确性,为推断产品可靠性提供了理论支撑。 相似文献
7.
对3种不同Ag含量材料(Sn-3.0Ag-0.5Cu,Sn-1.0Ag-0.5Cu,Sn-0.3Ag-0.7Cu)的焊点进行跌落实验,实验中施加的加速度载荷为峰值3200g,脉冲持续时间1ms的半正弦波形加速度,利用电学测试、光学显微镜和扫描电子显微镜确定了失效的焊点并对失效焊点进行分析。结果表明:3种材料焊点的失效位置基本都在靠近印刷电路板(PCB)侧,BAG封装最外围4个拐角处的焊点最先失效。Sn-3.0Ag-0.5Cu,Sn-1.0Ag-0.5Cu焊点的失效模式均为脆性断裂,Sn-0.3Ag-0.7Cu为韧-脆混合断裂。且随着Ag含量的降低,金属间化合物(IMC)的厚度逐渐减小,焊点的寿命逐渐提高。 相似文献
8.
9.
复合材料低速冲击损伤研究及等效模型的应用 总被引:1,自引:0,他引:1
复合材料低速冲击损伤的特殊性及危害性使得对航空复合材料冲击损伤的评估尤为重要。该文通过建立数值计算模型并结合实验数据解决了4个方面的应用问题:1)在ABAQUS子程序VUMAT中引入损伤模式及损伤演化,结合层间连接单元对层合板低速冲击损伤进行了模拟;2)损伤容限设计方法要求对含缺陷结构的极限强度做出正确的评估,通过ABAQUS子程序USDFLD引入损伤模式及材料折减方案,得到了含圆孔的层合板极限拉压强度;3)通过ABAQUS子程序UMAT引入损伤模式及刚度折减方案,结合层间连接单元,模拟了含预制分层的层合板压缩失效问题;4)针对共用铺层结构的工程有限元计算问题,提出了力学等效模型,将该模型应用到结构级的静力实验模拟并拓展至结构冲击模拟。 相似文献
10.
11.
Jianping Jing Feng Gao Janine Johnson Frank Z. Liang Richard L. Williams Jianmin Qu 《Engineering Failure Analysis》2009,16(5):1579-1586
In this paper, dynamic fracture of a single solder joint specimen is numerically simulated using the finite element method. The solder–IMC and IMC–Cu pad interfaces are modeled as cohesive zones. The simulated results show that under pure tensile loading, damage typically starts at the edge of the solder–IMC interface, then moves to IMC–Cu pad interface. Eventual failure is typically a brittle interfacial failure of the IMC–Cu interface. 相似文献
12.
Investigation on impact strength of the as-soldered Sn37Pb and Sn3.8Ag0.7Cu solder joints 总被引:1,自引:0,他引:1
Ning Zhang Yaowu Shi Zhidong Xia Yongping Lei Fu Guo Xiaoyan Li 《Journal of Materials Science: Materials in Electronics》2009,20(6):499-506
Charpy impact specimens of eutectic Sn37Pb and Sn3.8Ag0.7Cu solder joints with U-type notch were prepared to investigate the
joint impact strength. The gap sizes of the butt joint were selected at 0.3 and 0.8 mm. Compared with the values of 0.3 mm
joint gap, the impact absorbed energies of two solder joints were increased at the joint gap of 0.8 mm. The impact strengths
of Sn37Pb joints were higher than those of Sn3.8Ag0.7Cu joints in both cases. From the macrographic observation of the fracture
path, when the gap was 0.3 mm, the crack initiation of two solder joints located at the root of U-type notch then propagated
along one interface of the joint. For the Sn37Pb joints, the fracture path was not changed at 0.8 mm gap size. However, the
fracture path of Sn3.8Ag0.7Cu joint was totally changed and the fracture occurred not at the root of pre-U notch but from
one side of the solder/Cu interfaces. From the micrographic observation, the crack of the Sn37Pb joints was concentrated on
the Pb-rich layer in the vicinity of interfacial intermetallic (IMC) layer and the fracture morphology mainly appeared to
be a ductile-like structure. Meanwhile, the fracture of Sn3.8Ag0.7Cu joints propagated along either the interface of IMC/solder
or within the IMC layer and showed a brittle failure mode. 相似文献
13.
Xiaoyun Li Fangqiu Zu Zhongyue Huang Chong Wang Wenjin Zhang 《Journal of Materials Science: Materials in Electronics》2013,24(4):1231-1237
The intermetallic compound (IMC) growth behavior of Sn–3.5Ag–3.5Bi/Cu joint was investigated with a change in the solder melt structure during soldering and 180 °C isothermal aging. The results show that when the solders undergo liqiud–liquid structure transition (LLST), the IMC of the joint is thinner and more evenly distributed during soldering. The interface IMC is also thinner, and the quantity of Ag3Sn as well as Cu6Sn5 in the solder is relatively lower. However, the IMCs are more bulky after long-time aging at 180 °C. When the solders do not undergo LLST, microcracks form in the solder. Kirkendall voids are more abundant and interconnected after long, high-temperature aging. This finding indicates better joint reliability after than before LLST. The growth rate constants of the interface IMC for the two kinds of joints are calculated to be 1.94 × 10?12 and 9.71 × 10?13. The correlation of IMC growth behavior and melt state is analyzed from the viewpoints of LLST and atom diffusion. 相似文献
14.
W. H. Zhong Y. C. Chan B. Y. Wu M. O. Alam J. F. Guan 《Journal of Materials Science》2007,42(13):5239-5247
This paper evaluates the shearing behavior of ball grid array (BGA) solder joints on Au/Ni/Cu pads of FR4 substrates after
multiple reflow soldering. A new Pb-free solder, Sn–3Ag–0.5Cu–8In (SACI), has been compared with Sn–3Ag–0.5Cu (SAC) and Sn–37Pb
(SP) solders, in terms of fracture surfaces, shearing forces and microstructures. Three failure modes, ball cut, a combination
of solder shear and solder/pad bond separation, and pad lift, are assessed for the different solders and reflow cycles. It
is found that the shearing forces of the SP and SAC solder joints tend to increase slightly with an increase in the number
of reflow cycles due to diffusion-induced solid solution strengthening of the bulk solder and augmentation of the shearing
area. However, the shearing forces of the SACI solder joints decrease slightly after four cycles of reflow, which is ascribed
to the thermal degradation of both the solder/intermetallic compound (IMC) and IMC/Ni interfaces. The SACI solder joints yield
the highest strengths, whereas the SP solder joints give the smallest values, irrespective of the number of reflow cycles.
Thickening of the interfacial IMC layer and coarsening of the dispersing IMC particles within the bulk solders were also observed.
Nevertheless, the variation of shearing forces and IMC thickness with different numbers of reflow cycles was not so significant
since the Ni under layer acted as an effective diffusion barrier. In addition, the initially-formed IMC layer retarded the
further extensive dissolution of the pad material and its interaction with the solder. 相似文献
15.
H. Xiao X. Y. Li Y. X. Zhu J. L. Yang J. Chen F. Guo 《Journal of Materials Science: Materials in Electronics》2013,24(7):2527-2536
The intermetallic compound (IMC) growth behavior at SnAgCu/Cu solder joint interface under different thermal aging conditions was investigated, in order to develop a framework for correlating IMC layer growth behavior between isothermal and thermomechanical cycling (TMC) effects. Based upon an analysis of displacements for actual flip-chip solder joint during temperature cycling, a special bimetallic loading frame with single joint-shear sample as well as TMC tests were designed and used to research the interfacial IMC growth behavior in SnAgCu/Cu solder joint, with a focus on the influence of stress–strain cycling on the growth kinetics. An equivalent model for IMC growth was derived to describe the interfacial Cu-Sn IMC growth behavior subjected to TMC aging as well as isothermal aging based on the proposed “equivalent aging time” and “effective aging time”. Isothermal aging, thermal cycling (TC) and TMC tests were conducted for parameter determination of the IMC growth model as well as the growth kinetic analysis. The SnAgCu/Cu solder joints were isothermally aged at 125, 150 and 175 °C, while the TC and TMC tests were performed within the temperature range from ?40 to 125 °C. The statistical results of IMC layer thickness showed that the IMC growth for TMC was accelerated compared to that of isothermal aging based on the same “effective aging time”. The IMC growth model proposed here is fit for predicting the IMC layer thickness for SnAgCu/Cu solder joint after any isothermal aging time or thermomechanical cycles. In addition, the results of microstructure evolution observation of SnAgCu/Cu solder joint subjected to TMC revealed that the interfacial zone was the weak link of the solder joint, and the interfacial IMC growth had important influence on the thermomechanical fatigue fracture of the solder joint. 相似文献
16.
《Materials Science & Technology》2013,29(12):1478-1484
AbstractIn this study, the interfacial reaction and joint reliability of immersion Ag-plated Cu substrate with the Sn–0·7Cu (wt-%) ball–grid array (BGA) solder was investigated. During reflow, the Ag plating layer was dissolved completely into the molten Sn–Cu solder and some of the Cu layer was also dissolved into the molten solder. The dissolved Ag and Cu were precipitated as Ag3Sn and Cu6Sn5 intermetallic compounds (IMCs) in the solder matrix. Upon reflow, the Sn–Cu solder exhibits an off-eutectic reaction to produce the eutectic phase and precipitate (Cu6Sn5 and Ag3Sn). The Cu–Sn IMC layer was formed at the solder/Cu interface after reflow, and the IMC layer grew during aging treatment. During the shear tests, the failure mode switched from a bulk-related failure to an interface-related failure. After aging for 250 h, the joint failed partially at the solder/Cu6Sn5 interface. The brittle fracture was linked to the formation of thick Cu–Sn IMC layer. 相似文献
17.
18.
通过对SnAgCu焊膏/Cu焊接界面IMC层和力学性能进行分析,研究了助焊剂中添加咪唑类缓蚀剂A和喹啉类缓蚀剂B及其复配对SnAgCu焊膏焊接性能的影响.利用扫描电镜(SEM)和能量色散谱仪(EDS)分别对IMC层的微观结构和焊点的组织成分进行观察和分析,采用力学试验机测试焊点的剪切强度和拉伸强度,并通过SEM观察其断口形貌.研究结果表明:缓蚀剂对界面IMC层的生长起到一定控制作用,不添加任何缓蚀剂时,IMC层厚度不均匀,部分呈粗大的柱状结构,平均厚度为7.6μm;而添加0.5%A和0.5%B复配缓蚀剂的焊膏,IMC层最薄而且致密均匀,厚度为3.4μm;添加0.5%A和0.5%B复配缓蚀剂的焊膏,获得了最大的剪切强度和抗拉强度,其中剪切强度为47.92 MPa,剪切断裂模式为韧性断裂,抗拉强度为99.28 MPa,拉伸断裂模式为脆性断裂. 相似文献
19.
Keke Zhang Xiaojiao Zhang Ranfeng Qiu Hongxin Shi Yujie Liu 《Journal of Materials Science: Materials in Electronics》2014,25(4):1681-1686
The effect of ultrasonic wave (USW) and electric field (E) on the solderability of Sn2.5Ag0.7Cu0.1RE/Cu was investigated. Compared with the sample soldered conventionally, the solder joint obtained with USW and E assisted resulted in significant changes in the microstructure. The thickness and roughness of the interfacial Cu6Sn5 intermetallic compound (IMC) layer decreased by 39 and 56 %, respectively. The shear strength of the solder joint increased by 68 %, and the fracture mechanism of the solder joint transformed from brittle fracture occurred in the interfacial IMC layer to ductile fracture occurred in the solder alloy. The results reveal that reliable soldering of Sn2.5Ag0.7Cu0.1RE/Cu can be achieved with USW and E assisted, despite of low-halogen flux. 相似文献
20.
Yongxin Zhu Xiaoyan Li Chao Wang Ruiting Gao 《Journal of Materials Science: Materials in Electronics》2014,25(3):1429-1434
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. 相似文献