共查询到19条相似文献,搜索用时 62 毫秒
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运用莱卡显微镜、扫描电镜和能谱分析等手段,研究了稀土元素La的添加量对Sn3.5Ag0.5Cu钎料及其与Cu基体焊接后微观组织及性能的影响。结果表明:添加不同含量的稀土La均能使钎料及其与Cu基体焊接后组织与性能得到改善,其中以w(La)达到0.05%时为最优,显微硬度及剪切强度分别提高14%和10.7%。键参数函数计算结果表明La具有"亲Sn"倾向,可细化钎料组织,降低IMC(界面金属间化合物)的长大驱动力。 相似文献
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研制开发熔点在250~450℃之间的高温无铅软钎料一直是钎焊领域一大难题。熔点为300℃左右的Bi5Sb2Cu钎料因润湿性能和导电性能不良而受到限制。本文通过在Bi5Sb2Cu中添加不同含量Sn形成新型BiSbCuSn四元合金,来改善Bi5Sb2Cu合金的润湿性能和物理性能。结果表明:在Bi5Sb2Cu钎料合金中添加2-↑10wt.%Sn,BiSbCu钎料合金熔点呈下降趋势且幅度较大,但仍在250~450℃之间,润湿性能和导电性能明显改善。当Sn含量为10wt.%时,(Bi5Sb2Cu)10Sn钎料合金润湿性能和导电性能最好。 相似文献
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通过SEM和EDAX等,研究了La添加量对Sn3.5Ag0.5Cu钎料与Cu基体焊合界面IMC微观组织及性能的影响。结果表明:添加不同量的La均对Sn3.5Ag0.5Cu与Cu基体焊合后的组织有细化作用并增强其力学性能。其中以w(La)达到0.05%时最优,剪切强度可提高10.7%。材料热力学理论计算结果表明,La具有"亲Sn"倾向,添加少量La到Sn3.5Ag0.5Cu钎料中,可减小Cu6Sn5/Cu界面Sn的活度,降低IMC的长大驱动力。 相似文献
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在BiSbCu钎料中添加Sn,分析Sn对BiSbCu钎料合金钎焊工艺性能的主要指标——钎料熔点和铺展面积的影响.结果表明:在Bi5Sb2Cu钎料合金中加入Sn可以显著降低钎料的熔点和显著增强钎料合金的铺展性能.当Sn的质量分数为10%时,Bi5Sb2Cu钎料的铺展面积为26.22 mm2,钎焊工艺性能最好. 相似文献
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采用悬滴法测量了3种无铅钎料合金(Sn-3.0Ag-0.5Cu、Sn-0.7Cu与Sn-9.0Zn)在260℃时的表面张力,分别为525.5,534.8和595.4 mN/m;同时采用座滴法测量了其在260℃熔融状态下与Cu基板的接触角,分别为24.5°、28.0°和102.5°,并且与传统Sn-37.0Pb钎料进行了比较研究。结果表明,无铅钎料合金的表面张力与接触角均大于Sn-37.0Pb钎料。结合Young-Dupre公式讨论了钎料合金表面张力与其润湿性能的相关性,认为Sn基钎料合金在Cu基板上的润湿性能主要取决于其表面张力。 相似文献
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This study describes tests in which solder composition, substrate metallization, temperature, and dwell time were combined
in a factorially designed experiment to determine the effect of those factors on solder spread area. Measure of spread area,
reflowed solder shape, solder microstructure, and solder and interface chemistry were taken in order to provide insight about
the wetting mechanism(s). The reactivity of Au vs Cu metallization with solder was found to be a major factor in increasing
spread area. The role of increasing tin content is to increase spread and spread rate. A similar effect is seen by increasing
temperature. Time allowed for spread is a minor contributor to the spread area. Segregation of the tin and bismuth solder
components during the wetting process was observed which indicated the role of bismuth as a carrier species. Analysis of variance
methods based on the statistically designed experiments1a’lb were used to show how to generate a model which estimates the spread area as a function of the tested factors. 相似文献
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The effect of flux on the wetting characteristics of four lead-free solders, Sn-3.5Ag, Sn-0.7Cu, Sn-3.5Ag-4.8Bi, and Sn-3.8Ag-0.7Cu
(wt.%), on copper substrates have been studied at 240, 260, and 280°C. The fluxes investigated were rosin (R), mildly activated
rosin (RMA), and activated rosin (RA). The wetting tests were conducted using the sessile-drop method. Results showed that
fluxes significantly affect the wetting properties of the solders. Contact angles ranging from 10° to 30° for RMA, 20° to
30° for RA, and 35° to 60° for R were obtained. The effect of temperature on contact angle depended on the type of flux used.
The contact angle decreased with increasing temperature; however, in some cases the contact angle was independent of temperature.
The Sn-3.5Ag-4.8Bi exhibited the lowest contact angles indicating improved wettability with addition of bismuth. The microstructure
of the solder/copper interface was analyzed by scanning electron microscopy. 相似文献
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In this study, the contact angles of four lead-free solders, namely, Sn-3.5Ag, Sn-3.5Ag-4.8Bi, Sn-3.8Ag-0.7Cu, and Sn-0.7Cu
(wt.%), were measured on copper substrates at different temperatures. Measurements were performed using the sessile-drop method.
Contact angles ranging from 30° to 40° after wetting under vacuum with no fluxes and between 10° and 30° with rosin mildly
activated (RMA) and rosin activated (RA) fluxes were obtained. The Sn-3.5Ag-4.8Bi exhibited the lowest contact angles, indicating
improved wettability with the addition of bismuth. For all soldering alloys, lower contact angles were observed using RMA
flux. Intermetallics formed at the solder/Cu interface were identified as Cu6Sn5 adjacent to the solder and Cu3Sn adjacent to the copper substrate. The Cu3Sn intermetallic phase was generally not observed when RMA flux was used. The effect of temperature on contact angle was dependent
on the type of flux used. 相似文献
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Solderability was evaluated for four Pb-free alloys: 95.5Sn-4.3Ag-0.2Cu (wt.%), 95.5Sn-4.0Ag-0.5Cu, 95.5Sn-3.9Ag-0.6Cu, and
95.5Sn-3.8Ag-0.7Cu on oxygen-free electronic grade (OFE) Cu and Au-Ni plated Kovar substrates. The solderability metric was
the contact angle, θc, as determined by the meniscometer/wetting balance technique. Tests were performed at 230°C, 245°C, and 260°C using rosin-based,
mildly activated (RMA) flux, a rosin-based (R) flux, and a low-solids (LS) flux. The Pb-free solders exhibited acceptable
to poor solderability (35°<θc<60°) on Cu with the RMA flux. Nonwetting occurred in most tests using the R flux. Wetting was observed with the LS flux,
but only at 245°C and 260°C and with high contact angles. The solderability of the Pb-free solders improved at all test temperatures
on the Au-Ni plated Kovar substrate when using the RMA flux (30°<θc<50°). Wetting was observed with the R flux (35°<θc<60°) and LS flux (50°<θc<85°) for all temperatures. The Pb-free solders had generally lower wetting rates and longer wetting times on Cu than the
63Sn-37Pb solder. The wetting rate and wetting time data were superior on the Au-Ni plated Kovar substrates. In general, solderability,
as measured by θc along with the wetting rate and wetting time, did not exhibit a consistent dependence on the composition of the Sn-Ag-XCu
(X=0.2, 0.5, 0.6, and 0.7) alloys. The better performers were 95.5Sn-3.9Ag-0.6Cu alloy with the RMA flux (both Cu and Au-Ni
plated Kovar) and 95.5Sn-3.8Ag-0.7Cu with the R and LS fluxes (Au-Ni-Kovar, only). The solder-flux interfacial tension, γLF, had a significant impact on the θc values. The magnitudes of the contact angle θc suggested that the four Pb-free solders would experience higher solderability defect counts at the printed wiring assembly
level. 相似文献
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Lili Gao Liang Zhang Feng Ji Sheng-lin Yu Guang Zeng 《Microelectronic Engineering》2010,87(11):2025-7059
Recent years, the SnAgCu family of alloys has been found a widely application as a replacement for the conventional SnPb solders in electronic industry. In order to further enhance the properties of SnAgCu solder alloys, alloying elements such as rare earth, Bi, Sb, Fe, Co, Mn, Ti, In, Ni, Ge and nano-particles were selected by lots of researchers as alloys addition into these alloys. Rare earth (RE) elements have been called the ‘‘vitamin” of metals, which means that a small amount of RE elements can greatly enhance the properties of metals, such as microstructure refinement, alloying and purification of materials and metamorphosis of inclusions. In addition, a small amount of Zn addition has the ability to reduce undercooling efficiently and suppress the formation of massive primary Ag3Sn plates, and Bi/Ga has the ability to enhance the wettability of SnAgCu alloys as well as Ni. Moreover, adding Co/Fe/Ge can effectively refine microstructure, modify interfacial Cu-Sn compounds and increase the shear strength of joints with Cu. This paper summarizes the effects of alloying elements on the wettability, mechanical properties, creep behavior and microstructures of SnAgCu lead-free solder alloys. 相似文献
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Comparative study of interfacial reactions of Sn-Ag-Cu and Sn-Ag solders on Cu pads during reflow soldering 总被引:1,自引:0,他引:1
The interfacial reaction in soldering is a crucial subject for the solder-joint integrity and reliability in electronic packaging
technology. However, electronic industries are moving toward lead-free alloys because of environmental concerns. This drive
has highlighted the fact that the industry has not yet arrived at a decision for lead-free solders. Among the lead-free alloys,
Sn-3.5Ag and Sn-3.5Ag-0.5Cu are the two potential candidates. Here, detailed microstructural studies were carried out to compare
the interfacial reaction of Sn-3.5Ag and Sn-3.5Ag-0.5Cu solder with a ball grid array (BGA) Cu substrate for different reflow
times. The Cu dissolution from the substrate was observed for different soldering temperatures ranging from 230°C to 250°C,
and the dissolution was found to increase with time and temperature. Dissolution of Cu in the Sn-3.5Ag solder is so fast that,
at 240°C, 12 μm of the Cu substrate is fully consumed within 5 min. Much less dissolution is observed for the Sn-3.5Ag-0.5Cu
solder. In respect to such high dissolution, there is no significant difference observed in the intermetallic compound (IMC)
thickness at the interface for both solder alloys. A simplistic theoretical approach is carried out to find out the amount
of Cu6Sn5 IMCs in the bulk of the solder by the measurement of the Cu consumption from the substrate and the thickness of the IMCs
that form on the interface. 相似文献
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Jenn-Ming Song Truan-Sheng Lui Yea-Luen Chang Li-Hui Chen 《Journal of Electronic Materials》2006,35(5):929-936
This study investigated the microstructure and vibration properties of Sn-Zn and Sn-Zn-Bi alloys with different Zn contents.
Experimental results show that the hypoeutectic Sn-Zn-Bi alloy (with a Zn content of 5 wt.%) has the poorest damping capacity
and the lowest critical vibration cycles to failure due to a hardening effect by Bi and intergranular fracturing. On the other
hand, since the Zn/Sn interfaces at which internal friction may occur during vibration contribute to the dissipation of vibration
energy, the hypereutectic Sn-13Zn samples with numerous massive primary Zn needles possess superior damping capacity and vibration
life under constant vibration force conditions. 相似文献
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The interfacial intermetallics between Cu and solder were studied for four Sn-Pb compositions at the annealing temperatures
of 125°C, 150°C, and 175°C for up to 30 days. The η-phase (Cu6Sn5) layer formed during reflow continues to grow during annealing. An additional layer of ɛ-phase (Cu3Sn) forms at the η/Cu interface after an incubation annealing time. The thickness results fit a power-law relationship against
time with average exponents 0.69 and 0.44 for the η phase and the ɛ phase, respectively. On prolonged annealing, the proportions
of the individual phases in the total layer reach a steady state. 相似文献
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N. Dariavach P. Callahan J. Liang R. Fournelle 《Journal of Electronic Materials》2006,35(7):1581-1592
Soldering with the lead-free tin-base alloys requires substantially higher temperatures (∼235–250°C) than those (213–223°C)
required for the current tin-lead solders, and the rates for intermetallic compound (IMC) growth and substrate dissolution
are known to be significantly greater for these alloys. In this study, the IMC growth kinetics for Sn-3.7Ag, Sn-0.7Cu, and
Sn-3.8Ag-0.7Cu solders on Cu substrates and for Sn-3.8Ag-0.7Cu solder with three different substrates (Cu, Ni, and Fe-42Ni)
are investigated. For all three solders on Cu, a thick scalloped layer of η phase (Cu6Sn5) and a thin layer of ε phase (Cu3Sn) were observed to form, with the growth of the layers being fastest for the Sn-3.8Ag-0.7Cu alloy and slowest for the Sn-3.7Ag
alloy. For the Sn-3.8Ag-0.7Cu solder on Ni, only a relatively uniform thick layer of η phase (Cu,Ni)6Sn5 growing faster than that on the Cu substrate was found to form. IMC growth in both cases appears to be controlled by grain-boundary
diffusion through the IMC layer. For the Fe-42Ni substrate with the Sn-3.8Ag-0.7Cu, only a very thin layer of (Fe,Ni)Sn2 was observed to develop. 相似文献