共查询到20条相似文献,搜索用时 15 毫秒
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V. Sivasubramaniam N.S. Bosco J. Janczak-Rusch J. Cugnoni J. Botsis 《Journal of Electronic Materials》2008,37(10):1598-1604
The effects of particle reinforcement of Sn-4.0wt.%Ag-0.5wt.%Cu (SAC405) lead-free solder on interfacial intermetallic layer
growth and strength of the ensuing joints through short-term isothermal aging (150°C) were studied. Composite solders were
prepared by either incorporating 2 wt.% Cu (3 μm to 20 μm) or Cu2O (∼150 nm) particles into SAC405 paste. Aggressive flux had the effect of reducing the Cu2O nanoparticles into metallic Cu which subsequently reacted with the solder alloy to form the Cu6Sn5 intermetallic. While all solders had similar interfacial intermetallic growth upon reflow, both of the composite solders’
growth rates slowed through aging to reach a common growth rate exponent of approximately 0.38, considerably lower than that
of the nonreinforced solder (n = 0.58). The nanoscale reinforced solder additionally exhibited the highest tensile strength in both the initial and aged
conditions, behavior also attributed to its quick conversion to a stable microstructure. 相似文献
3.
E.H. Wong S.K.W. Seah C.S. Selvanayagam R. Rajoo W.D. van Driel J.F.J.M. Caers X.J. Zhao N. Owens M. Leoni L.C. Tan Y.-S. Lai C.-L. Yeh 《Journal of Electronic Materials》2009,38(6):884-895
This paper presents a comprehensive study of the resistance of solder joints to failure when subjected to strain rates that
simulate the conditions of drop impact experienced by a portable electronic product. Two test methods are used in this study:
the board-level drop-shock test (BLDST) and the board-level high-speed cyclic bend test (HSCBT). The performance of (i) 12
material combinations consisting of six solder alloys and two pad finishes, and (ii) 11 manufacturing variations covering
three vendors, two finishes, three immersion gold thicknesses, and three thermal aging conditions were investigated using
these two test methods. Correlations between the two test methods were performed. Quantitative correlation and sensitivity
coefficients for the failure modes and the measured characteristic parameters—number of drops to failure for BLDST and number
of cycles to failure for HSCBT—were evaluated. Finally, the potential of HSCBT as a test method for material selection and
for bridging board-level and product-level tests was demonstrated through generation of board strain versus number of cycles
to failure (S–N) curves of solder joints for six material systems, four bending frequencies, and two test temperatures. 相似文献
4.
Effect of Thermal Aging on Drop Performance of Chip Scale Packages with SnAgCu Solder Joints on Cu Pads 总被引:1,自引:0,他引:1
Because of the trend of miniaturization, the drop performance of portable electronic devices is becoming increasingly critical.
This study was focused on the influential factors in the drop performance of chip scale packages (CSPs) with Cu/SnAgCu solder
joints after thermal aging. Assembled CSP test boards were thermally aged at 100–150°C for up to 1,000 h before drop test.
Microstructural evolution in the bulk solder and the interfacial region was investigated after drop test. Crack propagation
by drop test and the fractured surfaces were examined by scanning electron microscopy. Kirkendall voiding at the solder/Cu
interface and the thickness of interfacial intermetallic compounds did not have a significant effect on the occurrence of
the first failure by drop test. Correlation between drop performance and microstructural changes was observed. A model was
built to explain the complex drop test results based on the relationship between microstructure and mechanical properties
of solder joints. 相似文献
5.
无铅BGA封装可靠性的力学试验与分析 总被引:4,自引:0,他引:4
着重研究了机械冲击和应力对无铅BGA封装焊点可靠性的影响,介绍了BGA封装的可靠性力学试验(跌落、弯曲试验)及其分析方法.通过对力学试验中失效焊点的分析以及借助ANSYS模拟工具,找出引起失效的根本原因,为开发性能更好、高可靠性的无铅材料、改进无铅工艺提供依据. 相似文献
6.
BGA焊点在板级跌落实验中的疲劳寿命估计 总被引:1,自引:0,他引:1
按照JEDEC标准对板级跌落实验的要求测试了有铅和无铅焊点的球栅阵列封装.用ANSYS软件建立了有限元分析模型,并用ANSYS/LS-DYNA直接求解器计算了典型结点的应力和应变,以及每次跌落时积累在焊点中的平均应变能密度.利用实验和模拟的结果重新计算了Darveaux模型中的常数,将这个模型的应用范围扩展到了跌落环境,并计算了各种条件下焊点的疲劳寿命. 相似文献
7.
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
8.
In this study, the effect of Zn (Zn = 1 wt.%, 3 wt.%, and 7 wt.%) additions to Sn-4Ag solder reacting with Ag substrates was
investigated under solid-state and liquid-state conditions. The composition and microstructure of the intermetallic compounds
(IMCs) significantly changed due to the introduction of different Zn contents. In the case of Sn-4Ag solder with 1 wt.% Zn,
a continuous Ag-Sn IMC layer formed on the Ag substrates; discontinuous Ag-Zn layers and Sn-rich regions formed on the Ag
substrates under liquid-state conditions when the Sn-4Ag solders contained 3 wt.% and 7 wt.% Zn. If 3 wt.% Zn was added to
Sn-4Ag solder, the Ag-Sn IMC would be transformed into a Ag-Zn IMC with increasing aging time. Rough interfaces between the
IMCs and the Ag substrates were observed in Sn-4Ag-7Zn/Ag joints after reflowing at 260°C for 15 min; however, the interfaces
between the IMCs and the Ag substrates became smooth for Sn-4Ag-1Zn/Ag and Sn-4Ag-3Zn/Ag joints. The nonparabolic growth mechanism
of IMCs was probed in the Sn-4Ag-3Zn/Ag joints during liquid-state reaction, and can be attributed to the detachment of IMCs.
On the other hand, the effect of gravity was also taken into account to explain the formation of IMCs at the three different
interfaces (bottom, top, and vertical) during the reflow procedure. 相似文献
9.
10.
The low-temperature Sn-9Zn-1.5Bi-0.5In-0.01P lead-free solder alloy is used to investigate the intermetallic compounds (IMCs)
formed between solder and Cu substrates during thermal cycling. Metallographic observation, scanning electron microscopy,
transmission electron microscopy, and electron diffraction analysis are used to study the IMCs. The γ-Cu5Zn8 IMC is found at the Sn-9Zn-1.5Bi-0.5In-0.01P/Cu interface. The IMC grows slowly during thermal cycling. The fatigue life
of the Sn-9Zn-1.5Bi-0.5In-0.01P solder joint is longer than that of Pb-Sn eutectic solder joint because the IMC thickness
of the latter is much greater than that of the former. Thermodynamic and diffusivity calculations can explain the formation
of γ-Cu5Zn8 instead of Cu-Sn IMCs. The growth of IMC layer is caused by the diffusion of Cu and Zn elements. The diffusion coefficient
of Zn in the Cu5Zn8 layer is determined to be 1.10×10−12 cm2/sec. A Zn-rich layer is found at the interface, which can prevent the formation of the more brittle Cu-Sn IMCs, slow down
the growth of the IMC layer, and consequently enhance the fatigue life of the solder joint. 相似文献
11.
It was reported in previous studies that the addition of Bi could improve the wettability and reduce the melting temperature
of Sn-Ag solders. This work investigates the effect of Bi on the interfacial reaction between Sn-Ag-xBi solders and the Cu substrate reflowed at 250°C for different times and thermally aged at 150°C for different durations.
Five types of Sn-Ag-based solders, Sn-3.7Ag-xBi (x = 0 wt.% to 4 wt.%), were used in this study. The microstructure of the interfacial Cu-Sn intermetallic compound (IMC) layers
between the solders and the Cu substrate was studied, and the thickness of the Cu-Sn IMCs in different solder/Cu systems has
been measured. It was found that the thickness of the Cu-Sn IMC layer decreased with increasing amount of Bi in both the reflow
and thermally aged condition. The effect of Bi addition on the interfacial reaction between the solder and the Cu substrate
was discussed based on the experimental results. 相似文献
12.
Konstantina Lambrinou Wout Maurissen Paresh Limaye Bart Vandevelde Bert Verlinden Ingrid De Wolf 《Journal of Electronic Materials》2009,38(9):1881-1895
This work addresses a new mode of brittle failure that occurs in the bulk of tin-based lead-free solder joints, unlike the
typical brittle failures that occur in the interfacial intermetallics. Brittle failures in the joint bulk result from the
low-temperature ductile-to-brittle transition in the fracture behavior of β-tin. The bulk embrittlement of these joints is
discussed by referring to the results of impact tests performed on both solder joints and bulk solder specimens. The mechanism
of bulk embrittlement is largely explained based on the results of a fractography study performed on the bulk joint failures
using scanning electron microscopy. 相似文献
13.
Effect of Interfacial Reaction on the Tensile Strength of Sn-3.5Ag/Ni-P and Sn-37Pb/Ni-P Solder Joints 总被引:2,自引:0,他引:2
This work investigates the effect of interfacial reaction on the mechanical strength of two types of solder joints, Sn-3.5Ag/Ni-P
and Sn-37Pb/Ni-P. The tensile strength and fracture behavior of the joints under different thermal aging conditions have been
studied. It is observed that the tensile strength decreases with increasing aging temperature and duration. Associated with
the tensile strength decrease is the transition of failure modes from within the bulk solder in the as-soldered condition
toward failures at the interface between the solder and the intermetallic compounds (IMCs). For the same aging treatment,
the strength of the Sn-3.5Ag/Ni-P joint degrades faster than that of Sn-37Pb/Ni-P. The difference between the two types of
joints can be explained by the difference in their interfacial reaction and growth kinetics. An empirical relation is established
between the solder joint strength and the Ni3Sn4 intermetallic compound thickness. 相似文献
14.
15.
The reliability of adhesion strength of the Sn-9Zn-1.5Ag-0.5Bi/Cu during isothermal aging has been investigated. Due to the
growth and decomposition of the intermetallic compound (IMC), the adhesion strength varies with aging at 150°C from 100, 400,
and 700–1,000 h as wetted at 250°C for 60 sec. The IMC layers are determined at the Sn-9Zn-1.5Ag-0.5Bi/Cu interface by an
x-ray diffractometer (XRD), an optical microscope (OM), a scanning electron microscope (SEM), an energy-dispersive spectroscope
(EDS), and a transmission electron microscope (TEM). The adhesion strength has been investigated by the pull-off test. The
results show that the Cu6Sn5, Cu5Zn8, and Ag3Sn IMCs are identified at the Sn-9Zn-1.5Ag-0.5Bi/Cu interface as aging. The adhesion strengths are 12.44±0.58, 8.57±0.43,
5.50±0.78, 4.32±0.78, and 3.32±0.43 MPa for aging times of 0 h, 100 h, 400 h, 700 h, and 1,000 h, respectively. 相似文献
16.
Noboru Wade Kepeng Wu Johji Kunii Seiji Yamada Kazuya Miyahara 《Journal of Electronic Materials》2001,30(9):1228-1231
The materials used in the present research are pure Sn metal and Sn-0.5% Cu, Sn-3.5%Ag, Sn-0.3%Sb, and Sn-3.5%Ag-0.5%Cu alloys.
Effects of Cu, Ag and Sb on the creep-rupture strength of lead-free solder alloys have been investigated. Creep tests are
performed at the stress and temperature range of 3 to 12 MPa and 378 to 403 K, respectively. A 3.5% addition of Ag had the
largest contribution to the creep-rupture strength of Sn metal among the single addition of 0.5%Cu, 3.5%Ag, and 0.3%Sb. The
combined addition of 3.5%Ag and 0.5%Cu makes the largest creep-rupture strength. The effects of these elements on the microstructure
of the lead-free alloys are also investigated with optical microscope (OM) and transmission electron microscope (TEM) observations. 相似文献
17.
Polina Snugovsky Heather McCormick Simin Bagheri Zohreh Bagheri Craig Hamilton Marianne Romansky 《Journal of Electronic Materials》2009,38(2):292-302
The results of an intensive reliability study on Pb-free ball grid array (BGA)/Sn-Pb solder assemblies as well as some lessons
learnt dealing with mixed assembly production at Celestica are described in this paper. In the reliability study, four types
of Pb-free ball grid array components were assembled on test vehicles using the Sn-Pb eutectic solder and typical Sn-Pb reflow
profiles with 205°C to 220°C peak temperatures. Accelerated thermal cycling (ATC) was conducted at 0°C to 100°C. The influence
of the microstructure on Weibull plot parameters and the failure mode will be shown. Interconnect defects such as nonuniform
phase distribution, low-melting structure accumulation, and void formation are discussed. Recommendations on mixed assembly
and rework parameters are given. 相似文献
18.
Excessive intermetallic compound (IMC) growth in solder joints will significantly decrease the reliability of the joints.
IMC growth is known to be influenced by numerous factors during the component fabrication process and in service. It is reported
that, other than temperature and holding time, stress can also influence the IMC growth behavior. However, no existing method
can be used to study the effect of stress state on IMC growth in a controlled manner. This paper presents a novel method to
study the effect of stress on interfacial IMC growth between Sn-Ag-Cu solder and a Cu substrate coated with electroless Ni
immersion Au (ENIG). A C-ring was used and in-plane bending induced tensile and compressive stresses were applied by tightening
the C-ring. Results revealed that in-plane compressive stress led to faster IMC growth as compared with in-plane tensile stress. 相似文献
19.
Effects of Co Addition on Bulk Properties of Sn-3.5Ag Solder and Interfacial Reactions with Ni-P UBM
Dong Hoon Kim Moon Gi Cho Sun-Kyoung Seo Hyuck Mo Lee 《Journal of Electronic Materials》2009,38(1):39-45
The effects of Co addition on the undercooling, microstructure, and microhardness of Sn-3.5Ag solder (all in wt.% unless specified
otherwise) and interfacial reactions with Ni-P under bump metallurgy (UBM) are investigated when the Co content varies from
0.01 wt.% to 0.7 wt.%. When more than 0.02 wt.% Co was added to Sn-3.5Ag solder, the undercooling of the Sn-3.5Ag solder
was significantly reduced and the microstructures coarsened with the increased eutectic region. In addition, the hardness
value increased as the Co content in Sn-3.5Ag increased. In the interfacial reactions with Ni-P UBM, a spalling phenomenon
of intermetallic compounds (IMCs) during reflow was prevented in the Sn-3.5Ag-xCo (x ≥ 0.02 wt.%). However, when more than 0.05 wt.% Co was added to Sn-3.5Ag, the IMC morphology changed from a bulky shape to
a plate-like shape. The bulky IMCs were Ni3Sn4 and the plate-like IMCs were Sn-Ni-Co ternary compounds. The main issues discussed include the relations between the morphological
changes and the IMC phases, the effects of Co addition on the prevention of IMC spalling, and the optimum level of Co addition. 相似文献
20.
Interfacial reactions in Ni-SnAg-Cu and Au/Ni/Cu-SnAg-Cu solder joints were investigated to understand the coupling effect
between different pads during soldering and thermal aging processes. Scanning electron microscopy (SEM) was used to characterize
the microstructures and phases. The element distributions in the joints were identified using the x-ray mapping technique.
The thickness variation of intermetallic compounds (IMCs) with aging time was also measured. The results showed that interfacial
reactions were not only affected by the compositions of solders and the local metallizations but the remote pads as well.
The Au surface finish had an effect on the growth of IMCs at the interfaces. No redeposition of (Au, Ni)Sn4 was found in the Au/Ni/Cu-SnAg-Cu solder joint. The effect of Cu on the formation of IMCs and redeposition of (Au, Ni)Sn4 was also discussed.
An erratum to this article can be found at 相似文献