共查询到20条相似文献,搜索用时 15 毫秒
1.
Xingsheng Liu Shuangyan Xu Guo-Quan Lu David A. Dillard 《Microelectronics Reliability》2002,42(12):1142-1891
Solder joint fatigue failure is a serious reliability concern in area array technologies, such as flip chip and ball grid array packages of integrated-circuit chips. The selection of different substrate materials could affect solder joint thermal fatigue lifetime significantly. The reliability of solder joint in flip chip assembly for both rigid and compliant substrates was evaluated by accelerated temperature cycling test. Experimental results strongly showed that the thermal fatigue lifetime of solder joints in flip chip on flex assembly was much improved over that in flip chip on rigid substrate assembly. Debonding area of solder joints in flip chip on rigid board and flip chip on flex assemblies were investigated, and it was found that flex substrate could slow down solder joint crack propagation rate. The mechanism of substrate flexibility on improving solder joint thermal fatigue was investigated by thermal mechanical analysis (TMA) technique. TMA results showed that flex substrate buckles or bends during temperature cycling and this phenomenon was discussed from the point of view of mechanics of the flip chip assembly during temperature cycling process. It was indicated that the thermal strain and stress in solder joints could be reduced by flex buckling or bending and flex substrates could dissipate energy that otherwise would be absorbed by solder joints. It was concluded that substrate flexibility has a great effect on solder joint reliability and the reliability improvement was attributed to flex buckling or bending during temperature cycling. 相似文献
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Chip Scale Package (CSP) solder joint reliability and modeling 总被引:1,自引:0,他引:1
A viscoplastic constitutive model was used to analyze the thermally induced plastic and creep deformation and low cycle fatigue behavior of the solder joints in Chip Scale Packages (CSP) mounted on Printed Circuit Boards (PCB). The time-dependent and time-independent viscoplastic strain rate and plastic hardening work factors of solder material were used in 2-D plane strain finite element models. The viscoplastic strain rate data was fitted to the viscoplastic flow equation. The plastic hardening factors were considered in the evolution equation. A viscoelastic constitutive model was used for molding compound. Finite element models, incorporating the viscoplastic flow and evolution equations for solder and the viscoelastic equations for molding compound, were verified by temperature cycling tests on assembled CSPs. The effect of the cyclic frequency, dwell time, and temperature ramp rate on the response of the viscoplastic deformation was studied for a tapeless Lead-on-Chip (LOC) CSP and a flexible substrate CSP. The ramp rate significantly affects the equivalent stress range in solder joints while a dwell time in excess of 10 min per half cycle does not result in increased strain range. The failure data from the experiments was fitted to the Weibull failure distribution and the Weibull parameters were extracted. After satisfactory correlation between the experiment and the model was observed, the effect of material properties and package design variables on the fatigue life of solder joints in CSPs was investigated and the primary factors affecting solder fatique life were subsequently presented. Furthermore, a simplified model was proposed to predict the solder fatigue life in CSPs. 相似文献
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Solder joint often plays a crucial role in the normal operation of electronic equipment due to its unique material properties and harsh working condition, making it very important to carry out the accurate reliability analysis of solder joint. The low-cycle fatigue due to temperature cycling and the creep brought by continuous high temperature are two dominant failure modes of the solder joint. Current modeling methods for these two mechanisms mainly focus on failure process of each mechanism separately, with little consideration of the coupling relationship in the material properties. This paper introduces a coupling damage model considering both low-cycle fatigue and creep. The coupling relationship between these two failure mechanisms is investigated with the effects of creep strain rate on the ductility and the effects of damage on mechanical properties of solder joint. The analysis of the former mechanism concerns the fatigue parameter of Coffin-Manson model, while the latter one focuses on the applied stress increasing with the accumulation of damage. Further, considering that creep degradation rate would increase once the cumulative damage reaches a trigger threshold, a generalized cumulative damage model is developed. Based on this assumption, a reliability model for solder joint considering the uncertainty of model parameters is then proposed. Finally, a case study of a lead-free solder joint is given to validate this method. 相似文献
6.
Vibration fatigue test and analysis methodology for flip chip solder joint fatigue life assessment have been developed by performing vibration tests with constant G-level and varying G-level input excitation. The linear cumulative damage analysis method (Miner’s rule) predicts non-conservative result for vibration fatigue life of flip chip solder joint. Finite element analysis (FEA) using a global-local-beam modeling method was used to calculate the natural frequency and were compared to experimental data. A quasi-static finite element analysis method was developed to investigate solder joint stress strain behavior for solder joint vibration fatigue life prediction. Harmonic finite element analysis was also carried out to predict solder joint fatigue life. Results from quasi-static analysis and harmonic analysis were compared. Based on Miner’s rule and stress amplitude results from FEA results, different assumed cumulative damage index (CDI) factors were investigated in fatigue life prediction. 相似文献
7.
焊点的质量与可靠性 总被引:1,自引:1,他引:0
李志民 《电子产品可靠性与环境试验》2005,23(2):31-34
主要介绍了Sn—Pb合金焊接点发生失效的各个失效阶段的各种表现形式,探讨发生失效的各种原因.如热应力与热冲击、金属的溶解、基板和元件过热、超声清洗的损害,以及如何在工艺上进行改进以改善焊点的可靠性,使焊点有良好的可靠性、不易损坏,能够承受变化的负载等,从而提高产品的质量。 相似文献
8.
A new reflow parameter, heating factor (Qη), which is defined as the integral of the measured temperature over the dwell time above liquidus, has been proposed in this report. It can suitably represent the combined effect of both temperature and time in usual reflow process. Relationship between reliability of the micro-ball grid array (micro-BGA) package and heating factor has been discussed . The fatigue failure of micro-BGA solder joints reflowed with different heating factor in nitrogen ambient has been investigated using the bending cycle test. The fatigue lifetime of the micro-BGA assemblies firstly increases and then decreases with increasing heating factor. The greatest lifetime happens at Qη near 500 s °C. The optimal Qη range is between 300 and 750 s °C. In this range, the lifetime of the micro-BGA assemblies is greater than 4500 cycles. SEM micrographs reveal that cracks always initiate at the point of the acute angle where the solder joint joins the PCB pad. 相似文献
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Comprehensive board-level solder joint reliability modeling and testing of QFN and PowerQFN packages
For quad flat non-lead (QFN) packages, board-level solder joint reliability during thermal cycling test is a critical issue. In this paper, a parametric 3D FEA sliced model is established for QFN on board with considerations of detailed pad design, realistic shape of solder joint and solder fillet, and non-linear material properties. It has the capability to predict the fatigue life of solder joint during thermal cycling test within ±34% error. The fatigue model applied is based on a modified Darveaux’s approach with non-linear viscoplastic analysis of solder joints. A solder joint damage model is used to establish a connection between the strain energy density (SED) per cycle obtained from the FEA model and the actual characteristic life during thermal cycling test. For the test vehicles studied, the maximum SED is observed mostly at the top corner of peripheral solder joint. The modeling predicted fatigue life is first correlated to thermal cycling test results using modified correlation constants, curve-fitted from in-house QFN thermal cycling test data. Subsequently, design analysis is performed to study the effects of 17 key package dimensions, material properties, and thermal cycling test condition. Generally, smaller package size, smaller die size, bigger pad size, thinner PCB, higher mold compound CTE, higher solder standoff, and extra soldering at the center pad help to enhance the fatigue life. Comparisons are made with thermal cycling test results to confirm the relative trends of certain effects. Another enhanced QFN design with better solder joint reliability, PowerQFN, is also studied and compared with QFN of the same package size. 相似文献
11.
Effect of substrate metallization on interfacial reactions and reliability of Sn-Zn-Bi solder joints
Ahmed Sharif 《Microelectronic Engineering》2007,84(2):328-335
The scope of this paper covers a comprehensive study of the lead-free Sn-Zn-Bi solder system, on Cu, electrolytic Ni/Au and electroless Ni(P)/Au surface finishes. This includes a study of the shear properties, intermetallic compounds at the substrate-ball interface and dissolution of the under bump metallization. The Sn-8Zn-3Bi (wt.%) solder/Cu system exhibited a low shear load with thick IMCs formation at the interface. The dissolution of the Cu layer in the Sn-Zn-3Bi solder is higher than that of the other two Ni metallizations. It was found that the formation of a thick Ni-Zn intermetallic compound (IMC) layer at the solder interface of the electrolytic Ni bond pad reduced the mechanical strength of the joints during high temperature long time liquid state annealing. The solder ball shear-load for the Ni(P) system during extended reflow increased with an increase of reflow time. No spalling was noticed at the interface of the Sn-Zn-3Bi solder/Ni(P) system. Sn-8Zn-3Bi solder with electroless Ni(P) metallization appeared as a good combination in soldering technology. 相似文献
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Board level solder joint reliability modeling and testing of TFBGA packages for telecommunication applications 总被引:2,自引:0,他引:2
Tong Yan Tee Hun Shen Ng Daniel Yap Xavier Baraton Zhaowei Zhong 《Microelectronics Reliability》2003,43(7):1117-1123
For thin-profile fine-pitch BGA (TFBGA) packages, board level solder joint reliability during the thermal cycling test is a critical issue. In this paper, both global and local parametric 3D FEA fatigue models are established for TFBGA on board with considerations of detailed pad design, realistic shape of solder joint, and nonlinear material properties. They have the capability to predict the fatigue life of solder joint during the thermal cycling test within ±13% error. The fatigue model applied is based on a modified Darveaux’s approach with nonlinear viscoplastic analysis of solder joints. A solder joint damage model is used to establish a connection between the strain energy density (SED) per cycle obtained from the FEA model and the actual characteristic life during the thermal cycling test. For the test vehicles studied, the maximum SED is observed at the top corner of outermost diagonal solder ball. The modeling predicted fatigue life is first correlated to the thermal cycling test results using modified correlation constants, curve-fitted from in-house BGA thermal cycling test data. Subsequently, design analysis is performed to study the effects of 14 key package dimensions, material properties, and thermal cycling test condition. In general, smaller die size, higher solder ball standoff, smaller maximum solder ball diameter, bigger solder mask opening, thinner board, higher mold compound CTE, smaller thermal cycling temperature range, and depopulated array type of ball layout pattern contribute to longer fatigue life. 相似文献
13.
《电子元件与材料》2017,(7)
研究了在热循环载荷条件下,不同厚度的金属间化合物IMC(Intermetallic Compound)层对焊点可靠性的影响。采用Anand本构模型描述无铅焊点在热载荷条件下的粘塑性力学行为,运用有限元模拟电子封装器件在热载荷循环下的应力应变的变化规律,确定关键焊点的位置,得到关键焊点的关键点的应力、应变与时间关系的曲线,分析IMC层厚度与寿命关系曲线,并确定其函数关系。研究表明:在热载荷条件下IMC层厚度越大,其焊点的可靠性越低,寿命越短。在IMC层厚度为8.5μm时,IMC厚度对焊点寿命的影响率出现明显的变化,影响率由–32.8突然增加到–404,当IMC厚度为14.5μm时,焊点的寿命值出现了跳跃。 相似文献
14.
Mercado L.L. Sarihan V. Guo Y. Mawer A. 《Advanced Packaging, IEEE Transactions on》2000,23(3):415-420
A variety of parameters impact package reliability. One set of parameters that does not get much attention is the variations in package design that are assembly and vendor related. This study shows that solder pad size is important in solder joint reliability. Differences in solder pad size due to different vendors and processes can affect the reliability considerably. The impact of substrate thickness on package reliability has been shown in finite element stress analysis, moire interferometry experiments, and reliability tests. However, in certain cases, the pad size effect can be so significant that it overrides the impact of substrate thickness. This work indicates that in order to obtain good correlation between predictive engineering results and reliability tests data, this factor should not be ignored. In this study, finite element simulation has been used to quantify the pad size effect on the BGA reliability in the PBGA package. Air-to-air thermal cycling test results were compared with FEM predictions. Optimized pad sizes are discussed and the impact on the solder joint reliability is predicted. Solder pad size effect was found to be a dominant feature in correlating test data with predictions 相似文献
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Effect of rare earth element addition on the microstructure of Sn-Ag-Cu solder joint 总被引:6,自引:0,他引:6
Bo Li Yaowu Shi Yongping Lei Fu Guo Zhidong Xia Bin Zong 《Journal of Electronic Materials》2005,34(3):217-224
The effects of minimal rare earth (RE) element additions on the microstructure of Sn-Ag-Cu solder joint, especially the intermetallic
compounds (IMCs), were investigated. The range of RE content in Sn-Ag-Cu alloys varied from 0 wt.% to 0.25 wt.%. Experimental
results showed that IMCs could be dramatically repressed with the appropriate addition of RE, resulting in a fine microstructure.
However, there existed an effective range for the RE addition. The best RE content was found to be 0.1 wt.% in the current
study. In addition to the typical morphology of Ag3Sn and Cu6Sn5 IMCs, other types of IMCs that have irregular morphology and uncertain constituents were also observed. The IMCs with large
plate shape mainly contained Ag and Sn, but the content of Ag was much lower than that of Ag3Sn. The cross sections of Cu6Sn5 IMCs whiskers showed various morphologies. Furthermore, some eutectic-like structures, including lamellar-, rod-, and needle-like
phases, were observed. The morphology of eutectic-like structure was related to the RE content in solder alloys. When the
content of RE is 0.1 wt.%, the needle-like phase was dominant, while the lamellar structure prevailed when the RE content
was 0.05 wt.% or 0.25 wt.%. It is suggested that the morphology change of the eutectic-like structure directly affects the
creep properties of the solder joint. 相似文献
17.
Component placement in an electronic product is usually derived using manufacturability or electromagnetic effects as the defining factors. The effect of placement on component reliability is rarely studied. High integration level of modern products provides advantages in high speed electronics but can severely degrade the reliability of components, unless certain design rules are met.In this paper the relation between placement and the solder joint reliability of a BGA components is studied with computational methods in 3-D and verified with experimental tests. Finite element method is utilized to calculate the accumulation of plastic work in solder joints. Based on the failure criteria obtained in the process, simple design rules are extracted and presented. 相似文献
18.
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
19.
Pang J.H.L. Chong D.Y.R. Low T.H. 《Components and Packaging Technologies, IEEE Transactions on》2001,24(4):705-712
The reliability concern in flip-chip-on-board (FCOB) technology is the high thermal mismatch deformation between the silicon die and the printed circuit board that results in large solder joint stresses and strains causing fatigue failure. Accelerated thermal cycling (ATC) test is one of the reliability tests performed to evaluate the fatigue strength of the solder interconnects. Finite element analysis (FEA) was employed to simulate thermal cycling loading for solder joint reliability in electronic assemblies. This study investigates different methods of implementing thermal cycling analysis, namely using the "dwell creep" and "full creep" methods based on a phenomenological approach to modeling time independent plastic and time dependent creep deformations. There are significant differences between the "dwell creep" and "full creep" analysis results for the flip chip solder joint strain responses and the predicted fatigue life. Comparison was made with a rate dependent viscoplastic analysis approach. Investigations on thermal cycling analysis of the temperature range, (ΔT) effects on the predicted fatigue lives of solder joints are reported 相似文献
20.
J. Liang S. Downes N. Dariavach D. Shangguan S. M. Heinrich 《Journal of Electronic Materials》2004,33(12):1507-1515
Reliability of lead-free solder joints has been a hot topic widely debated in the electronic industry. Most published data
indicate that a change to lead-free soldering has the potential benefit of more reliable solder joints than the current Sn-Pb
eutectic solder joints. However, in reality many mechanical, metallurgical, thermal, and environmental factors affect the
service reliability of solder joints. This paper tries to shed some light on the effects of mechanical loading and thermal
conditions on solder joint reliability. These conditions are determined not only by external environments but also by the
solder alloy itself and the joint geometry. Analyses with first principles are carried out on solder joints of both areal
array and peripheral packages. Effects on fatigue life of solder joint geometry, thermal and mechanical characteristics of
components and substrate materials, and application conditions are discussed. The analysis helps explain why lead-free solder
joints may not be more reliable in certain application conditions than the current Sn-Pb eutectic solder joints. 相似文献