共查询到20条相似文献,搜索用时 15 毫秒
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A large number of lead-free Sn-Ag-Cu controlled collapse chip connection (C4) solder joints (∼100 μm in diameter) in flip-chip microelectronic packages were studied by electron backscatter diffraction (EBSD) in order to describe
the statistical distribution of grain size and coincident site lattice boundaries associated with 60 deg twins in the Sn phase,
as a function of silver content. It is shown that lower silver content results in smaller grains, and a lower propensity for
grains to exhibit twinning symmetries. Indirect measurements of the creep properties of these joints were also obtained as
a function of silver content, showing that, in the strain rate and temperature conditions that are the most relevant to the
microelectronic industry, solder joints with low silver content are more susceptible to creep deformation. 相似文献
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提出了一种对微电子封装器件中焊点剪切强度进行测试的方法,可有效降低测试误差。利用该方法,对Sn—Ag—Cu无铅焊料分别在Cu基板和Ni-P基板上形成的焊点,经不同的热时效后的剪切强度进行了测量,并对断裂面的微观结构进行了研究。结果表明,新的剪切测试方法误差小,易于实施,焊点剪切强度、断裂面位置与焊料在不同基板界面上金属间化合物的形貌、成分有关。 相似文献
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浅谈Sn-Ag-Cu无铅焊料的可靠性 总被引:3,自引:0,他引:3
随着电子组装技术的发展,电子产品在制造过程中使用的焊料也随之更新换代,由原来的使用锡铅焊料改为使用无铅焊料,特别是Sn-Ag-Cu焊料,以满足WEEE和RoHS指令以及其他方面的要求。然而,使用无铅焊料却带来了一系列的问题,这些问题自然影响到产品的可靠性和使用寿命,因此,成为业界最关注的热点问题。文章主要讨论了Sn-Ag-Cu焊料的可靠性等问题。 相似文献
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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
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采用Sn0.45A g0.68Cu亚共晶无铅钎料通过热浸焊获得铜接头,在-45~125℃的温度循环区间内对焊接接头进行200、400、600、800、1000周期高低温热冲击循环实验,分析了焊点的剪切强度变化,组织演变及界面IM C的生长规律。结果表明:焊点组织中弥散分布的Cu6Sn5相内部晶粒逐渐粗化长大,最后转变为圆形或者椭圆形;焊点界面IM C层厚度明显增厚,且由最初的细小扇贝状转变为大的波浪状,最终趋于平缓;焊点的剪切强度随热冲击循环周期的增加而急剧下降,经400周期的热冲击循环之后,焊点的剪切强度已下降了约22.5%,在400周期的热冲击循环后开始变得平缓,最后趋于稳定。 相似文献
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S. Lotfian J.M. Molina-Aldareguia K.E. Yazzie J. Llorca N. Chawla 《Journal of Electronic Materials》2013,42(6):1085-1091
The reliability of Pb-free solder joints is controlled by their microstructural constituents. Therefore, knowledge of the solder microconstituents’ mechanical properties as a function of temperature is required. Sn-Ag-Cu lead-free solder alloy contains three phases: a Sn-rich phase, and the intermetallic compounds (IMCs) Cu6Sn5 and Ag3Sn. Typically, the Sn-rich phase is surrounded by a eutectic mixture of β-Sn, Cu6Sn5, and Ag3Sn. In this paper, we report on the Young’s modulus and hardness of the Cu6Sn5 and Cu3Sn IMCs, the β-Sn phase, and the eutectic compound, as measured by nanoindentation at elevated temperatures. For both the β-Sn phase and the eutectic compound, the hardness and Young’s modulus exhibited strong temperature dependence. In the case of the intermetallics, this temperature dependence is observed for Cu6Sn5, but the mechanical properties of Cu3Sn are more stable up to 200°C. 相似文献
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Andreas R. Fix Gabriel A. López Ingo Brauer Wolfgang Nüchter Eric J. Mittemeijer 《Journal of Electronic Materials》2005,34(2):137-142
The effects of Cu as pad material and of the metallization of pad (with Sn) and component (with Ni) on the evolving microstructure
of lead-free solder joints were studied. A solder paste with composition 95.5wt.%Sn-4.0wt.%Ag-0.5wt.%Cu was used. Partial
dissolution of the Cu substrate led to a change in the overall composition of the solder, which caused a precipitation morphology
different from the one expected regarding the initial composition. Kinetics of growth of the Cu6Sn5 phase, as particles in the bulk of the solder and as a reaction layer adjacent to the Cu pad, was studied in the temperature
range 125–175°C. 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
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Jae-Yong Park Choong-Un Kim Ted Carper Viswanadham Puligandla 《Journal of Electronic Materials》2003,32(11):1297-1302
This paper is a study of the phase equilibria of the Sn-3.8Ag-0.7Cu alloy investigated by a differential cooling method. The
difficulty in assessing phase equilibria of the Sn-Ag-Cu (SAC) system because of the insufficient resolution of conventional
characterization techniques is solved by inducing preferential growth of a solid phase in a melt by holding the alloy at the
solid-liquid phase-equilibrium field. Application of the technique to Sn-3.8Ag-0.7Cu with varying holding temperatures yielded
results that the alloy is slightly off eutectic composition. The phase-formation sequence of the alloy during solidification
was found to be Ag3Sn, β-Sn, and finally the ternary eutectic microstructure. 相似文献
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Peter Zimprich Usman Saeed Brigitte Weiss Herbert Ipser 《Journal of Electronic Materials》2009,38(3):392-399
Reliability and quality control of microelectronics depend on a detailed understanding of the complex thermomechanical properties
of miniaturized lead-free solder joints. With the continuous reduction in size of modern electronic devices, including also
the size of the solder joints themselves, mechanical constraint effects may become of importance for the reliability of the
joints. In the present study stress relaxation tests in tensile mode were performed on model solder joints consisting of eutectic
Sn-3.5Ag solder between Cu substrates. The gap size of the joints was varied between 750 μm and 150 μm in order to investigate the variation of the mechanical properties as a function of the gap size. As it turned out, stress
relaxation was dramatically reduced when the solder gaps became smaller due to constraint effects already well known from
earlier measurements of the tensile strength. By employing a traditional creep model, the stress exponents and the activation
energies were derived and compared with available data in the literature. The consequences of these constraint effects for
the case of thermomechanical fatigue are discussed. 相似文献
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Growth of Sn and intermetallic compounds in Sn-Ag-Cu solder 总被引:2,自引:0,他引:2
L. P. Lehman S. N. Athavale T. Z. Fullem A. C. Giamis R. K. Kinyanjui M. Lowenstein K. Mather R. Patel D. Rae J. Wang Y. Xing L. Zavalij P. Borgesen E. J. Cotts 《Journal of Electronic Materials》2004,33(12):1429-1439
The microstructure of the Sn-Ag-Cu solder is examined by optical microscopy and scanning electron microscopy (SEM) for various
compositions near the ternary eutectic for different cooling rates from the solder melt. Focus is on the size and orientation
of Sn grains as indicated by cross-polarized, light optical microscopy, and pole figures from x-ray diffraction. We find that
both composition and cooling rate have strong influences on Sn grain size, with Sn grain size increasing an order of magnitude
as Cu concentration increases from 0% to 1.1%. Cyclic growth twinning, with twinning angles near 60°, is observed in Sn-Ag-Cu
alloys near the composition Sn-3.9Ag-0.6Cu. 相似文献
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Experimental Wettability Study of Lead-Free Solder on Cu Substrates Using Varying Flux and Temperature 总被引:2,自引:0,他引:2
Dong-Xia Xu Yong-Ping Lei Zhi-Dong Xia Fu Guo Yao-Wu Shi 《Journal of Electronic Materials》2008,37(1):125-133
The selection of soldering flux plays a critical role in promoting wetting and product reliability of printed circuit board
assemblies. In this study, the effects of fluxes on the wetting characteristics of the Sn-3.0Ag-0.5Cu solder alloy on Cu substrates
was researched by using various flux systems at different soldering temperatures. Because of the distinct characteristic of
the lead-free solder—poor wettability—three kinds of fluxes [no-clean flux with high solid content (NCF), rosin mildly activated
flux (RMA) and water-soluble flux (WSF)] were chosen for the wetting experiments. The wetting time and force were the evaluating
indicators. The experimental observations indicated that the wettability clearly depended on the soldering temperature and
flux system when using the same solder. Furthermore, the corrosion potential of flux residues was measured by surface insulation
resistance (SIR) testing. Scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDS) were used to determine
the contents of the flux residues and corrosion products. 相似文献
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Yi-Shao Lai Jenn-Ming Song Hsiao-Chuan Chang Ying-Ta Chiu 《Journal of Electronic Materials》2008,37(2):201-209
In this work, we present ball impact test (BIT) responses and fractographies obtained at an impact velocity of 500 mm/s on
Sn-4Ag-0.5Cu, Sn-1Ag-0.5Cu, Sn-1Ag-0.5Cu-0.05Ni, Sn-1.2Ag-0.5Cu-0.05Ni, and Sn-1Ag-0.5Cu-0.05Ge package-level solder joints.
The solder joints are bonded on substrate pads of either immersion tin (IT) or direct solder on pad (DSOP) surface finishes.
Differences of BIT results with respect to multi-reflow are also reported. Taking the impact energy as an indication of board-level
drop reliability of the solder joints, the BIT results indicate that better reliability can be achieved by adopting Sn-Ag-Cu
solder alloys with low Ag weight contents as well as IT substrate pad finish rather than DSOP. Moreover, the addition of Ni
or Ge to the solder alloy provides a large improvement; Ni alters the interfacial intermetallic compound (IMC) structure while
Ge enhances the mechanical behavior of the bulk solder. 相似文献
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在无铅BGA封装工艺过程中,通过不同组分的BGA焊球合金与焊膏合金组合焊接、焊膏助焊剂活性剂不同配比及其不同再流焊接条件等实验,对焊料合金和助焊剂配比、再流焊接峰值温度、再流保温时间等参数变化,以降低BGA焊点空洞缺陷进行了研究。结果表明选用相同或相似的BGA焊球和焊膏合金组合焊接、选用活性强的焊膏、选择焊接保温时间较长均有助于降低BGA焊点空洞缺陷产生的几率和空洞面积,BGA焊点最佳再流焊接峰值温度为240℃,当峰值温度设置为250℃时,BGA焊点产生空洞缺陷几率会比240℃高出25%~30%。 相似文献