共查询到19条相似文献,搜索用时 125 毫秒
1.
添加微量稀土元素的SnAgCu无铅钎料的研究 总被引:7,自引:0,他引:7
介绍目前国际上较为公认的SnAgCu系无铅钎料的特点,并汇总了国际上相关专利的情况.同时,结合本实验室的专利技术,介绍了添加微量稀土对SnAgCu系无铅钎料性能的影响,并着重研究了稀土对显微组织,特别是金属间化合物的影响规律.研究结果表明:从综合性能角度考虑,添加稀土的作用明显,特别是显著改善了钎料的抗蠕变性能,稀土添加量的最佳范围在w(0.05~0.25)%之间.适量的稀土添加,可有效抑制金属间化合物的生长,细化组织. 相似文献
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Sn-Zn系无铅钎料最新进展 总被引:1,自引:0,他引:1
Sn-Zn系钎料熔点与传统Sn-37Pb钎料十分接近,成本低廉,被研究者所推崇。由于Zn的存在导致Sn-Zn钎料润湿性差及抗氧化性不足,阻碍了该钎料的发展。添加合金元素和纳米颗粒是改善Sn-Zn钎料组织和性能行之有效的方法之一,为国内外研究者所推崇。结合国内外Sn-Zn系无铅钎料最新研究成果,探讨添加微量的合金元素In、Ni、Cr、Ga、Bi、Cu、Al、Ag、稀土元素及纳米颗粒对钎料润湿性、抗氧化性、力学性能、显微组织和界面组织的影响,同时简述有关钎剂对Sn-Zn的影响,并对Sn-Zn系钎料的发展趋势进行分析与展望。 相似文献
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微量元素对Sn-0.7Cu无铅钎料抗氧化性能的影响 总被引:2,自引:0,他引:2
以Sn-0.7Cu系无铅钎料合金为基础,添加微量的P、Ge、Ga、RE元素,进行了280℃大气环境下氧化试验,通过对含有不同微量元素的无铅钎料表面氧化状况的对比及分析,研究了不同微量元素对Sn-0.7Cu无铅钎料抗氧化性能的影响。发现当P和Ga同时添加时,得到Sn-0.7Cu-(0.001~0.1)P-(0.0001~0.1)Ga无铅钎料的抗氧化性能高于Sn-0.7Cu-(0.001~0.1)P和Sn-0.7Cu-(0.0001~0.1)Ga的抗氧化性能。 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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Because of excellent wetting and mechanical properties, SnAgCu solder alloys have been regarded as the most promising Pb-free
substitutes for the SnPb solder. The Sn-3.8Ag-0.7Cu solder has garnered attention because of its creep resistance. However,
under the drives of increasingly finer pitch design and severe service conditions, novel lead-free solders with higher creep
performance may be needed. Adding a surface-active element to an alloy is an effective way to improve the high-temperature
performance of the solder. The present work focuses on the effect of rare earth (RE) on the physical properties, spreading
property, and mechanical properties of SnAgCu solder. Results show that the creep-rupture life of SnAgCu solder joints at
room temperature could be notably increased by adding a minute amount of RE, up to 7 times more than that of SnAgCu solder
joints when containing 1.0wt.%RE. The differential scanning calorimetry (DSC) curves indicated that the melting temperature
of SnAgCu solder with RE increased a little, and no lower melting-temperature, eutectic endothermal peak appears on the DSC
curve. The electrical conductivity of the solder decreased slightly, but it is still superior to the SnPb eutectic solder.
Compared to that of SnPb solder, the coefficient of thermal expansion (CTE) of SnAgCu (RE) is closer to copper, which usually
serves as the substrate of printed circuit boards (PCBs). It is assumed that this will comparably reduce the thermal stress
derived from thermal mismatch between the solder and the PCBs. The RE had no apparent effect on the spreading property, but
when RE added up to 1.0 wt.%, the spreading area of the solder on the copper substrate decreased, obviously, because of mass
oxide. The RE improved the ultimate tensile strength little, but it increased the elongation up to 30%. However, as the content
of the RE increases, the elongation of the solder gradually decreased to the level of SnAgCu when the RE exceeds 0.25 wt.%.
Additionally, RE made the elastic modulus of SnAgCu solder increase, so the resistance to elastic deformation of the solder
is enhanced. The microstructure of SnAgCuRE led to a refining trend as the RE content increased. The RE compounds appeared
in the solder when RE was 0.1 wt.%. This deteriorates the mechanical properties of the solder. The fractography of the tensile
specimen containing 0.1 wt.% indicated a superior ductility to Sn-3.8Ag-0.7Cu bulk solder. However, as RE is increased to
1.0 wt.%, the fractography shows less ductile characteristics, which is believed to serve as the reason that the elongation
of solder degrades as RE increases. Summarily, the most suitable content of RE is within 0.05–0.5 wt.% and is inadvisable
beyond 1.0 wt.%. 相似文献
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Janne J. Sundelin Sami T. Nurmi Toivo K. Lepistö Eero O. Ristolainen 《Journal of Electronic Materials》2006,35(7):1600-1606
The effect of microstructure on the creep properties and the failure mechanism of SnAgCu solder joints was studied. Single
overlap shear specimens made of FR-4 printed circuit boards (PCBs) with organic solderability preservative (OSP), NiAu, and
immersion Sn surface finish were reflow-soldered with hypoeutectic, eutectic, and hypereutectic SnAgCu solder paste. Creep
tests of the solder joints were performed at 85°C and 105°C under constant load. The effect of microstructure on the creep
behavior of the joints was studied by examining the fracture surfaces and cross-sectional samples of the tested joints. Results
show that the intermetallic compound at the interface between the PCB and solder affects the fracture behavior of SnAgCu solder
joints, thus creating a significant difference in the creep properties of solder joints on different surface finishes. Composition
of SnAgCu solder was also found to affect the creep properties of the joints. 相似文献
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The Sn-0.7%Cu alloy has been considered as a lead-free alternative to lead-tin alloys. In this work, various small amounts
of rare earth (RE) elements, which are mainly Ce and La, have been added to the Sn-0.7%Cu alloy to form new solder alloys.
It was found that the new alloys exhibit mechanical properties superior to that of the Sn-0.7%Cu alloy. In particular, the
addition of up to 0.5% of RE elements is found to refine the effective grain size and provide a fine and uniform distribution
of Cu6Sn5 in the solidified microstructure. Tensile, creep, and microhardness tests were conducted on the solder alloys. It was found
that significant improvements of the tensile strength, microhardness, and creep resistance were obtained with RE element addition.
Upon aging at 150°C for 20 h, the microstructure of Sn-Cu-RE is more stable than that of the Sn-Cu alloy. 相似文献
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Study on the microstructure of a novel lead-free solder alloy SnAgCu-RE and its soldered joints 总被引:10,自引:0,他引:10
This paper focused on the microstructure of SnAgCu-rare earth (RE) solder alloy and its small single-lap joints, focusing
on phases present and the distribution of RE in the SnAgCu solder. Energy dispersive x-ray (EDX) analysis was used to observed
the RE-rich phase. The RE atoms also tended to aggregate at boundaries of primary dendrites in the joints and form as a weblike
structure, which surrounded the dendrites and restrained the dendrites from sliding or moving. It is assumed that this would
strengthen the boundaries and increase the resistance to creep deformation of the solder matrix. The creep-rupture life of
joints can be remarkably increased, at least seven times more than that of SnAgCu at room temperature. The aggregation mechanism
of RE at dendrite boundaries in SnAgCu solder joints was presented. The drive for RE atoms to aggregate at the boundary is
the difference of the lattice-aberration energy between the interior and the boundaries of the dendrites, which is caused
by a solution of RE atoms. 相似文献
16.
Weimin Xiao Yaowu Shi Yongping Lei Zhidong Xia Fu Guo 《Journal of Electronic Materials》2006,35(5):1095-1103
Lead-free solders with excellent material properties and low cost are essential for the electronics industry. It has been
proved that mechanical properties of SnAgCu alloys can be remarkably improved with a minute addition of rare earth (RE) elements.
For comparison and optimization, three valuable solder candidates, Sn3.8Ag0.7Cu0.05RE, Sn3Ag0.5Cu0.05RE, and Sn2.9Ag1.2Cu0.05RE,
were chosen due to the excellent properties of their own SnAgCu basic alloys. Wetting properties, melting temperature, bulk
tensile properties, and joint tensile and shear properties were investigated. In addition, the microstructures of solder joints
were observed and the effects of microstructure on mechanical properties were analyzed. Experimental results indicated that
the tensile and shear strengths of solder joints were decreased from Sn3.8Ag0.7Cu0.05RE, Sn2.9Ag1.2Cu0.05RE, to Sn3Ag0.5Cu0.05RE,
in order. Such difference in mechanical properties could be attributed to the influence of slightly coarse or strong Cu6Sn5 scallops in the reaction layer as well as superior eutectic network and large volume percentage of large primary intermetallic
compounds (IMCs) inside the solder joints. It is also suggested that the size and volume percentage of large primary IMCs
inside the solder be controlled. In addition, serration morphology was observed at the edge of large primary and eutectic
IMCs in the three solder joints, which could be related to the content of Ag, Cu, and RE. The serration morphology was proved
to be beneficial to mechanical properties theoretically. Furthermore, the three alloys investigated possessed similar wetting
properties, melting temperatures, and bulk tensile properties. 相似文献
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Microstructure characterization of SnAgCu solder bearing Ce for electronic packaging 总被引:1,自引:0,他引:1
Liang Zhang Song-bai Xue Li-li GaoWei Dai Feng JiYan Chen Sheng-lin Yu 《Microelectronic Engineering》2011,88(9):2848-2851
The creep-rupture lives of Sn3.8Ag0.7Cu and Sn3.8Ag0.7Cu0.03Ce lead-free solder joints for electronic packaging were investigated, respectively. And the relationship between creep behavior and intermetallic compound (IMC: Ag3Sn, Cu6Sn5, CeSn3) particles in SnAgCu/SnAgCuCe solder joints has been obtained. Meanwhile, rare earth Ce concentration gradient and retardation effect of Ce on the IMC layer have been observed at the solder/Cu interface. Moreover, aging reaction of Sn and Cu, and the effect mechanism of rare earth Ce on two IMCs (Cu6Sn5 and Cu3Sn) are reported. 相似文献
18.
Thermal cycling reliability of SnAgCu and SnPb solder joints: A comparison for several IC-packages 总被引:6,自引:0,他引:6
Bart Vandevelde Mario Gonzalez Paresh Limaye Petar Ratchev Eric Beyne 《Microelectronics Reliability》2007,47(2-3):259-265
This paper deals with a comparison study between SnPb and SnAgCu solder joint reliability. The comparison is based on non-linear finite element modelling. Three packages have been selected: silicon CSP, underfilled flip chip and QFN package. Also the effect of thermal cycling conditions has been investigated. Comparing the induced inelastic strains in the solder joint, the lead-free SnAgCu generally scores better thanks to the lower creep strain rate. On the other hand for the CSP and flip chip package, SnAgCu scores worse for the more extreme loading conditions when the inelastic dissipated energy density is selected as damage parameter. The main reason is that due to the lower creep strain rate, the stresses become higher for SnAgCu resulting in higher hysteresis loops with more dissipated energy per cycle. For the QFN package, SnAgCu scores much better. 相似文献
19.
通过大量的数据信息分析了各研究机构在无铅焊料方面的研究成果,在目前流行使用的无铅焊料的基础上,进一步研究并比较了其中的Sn-Cu系列与具有专利限制的SnAgCu系列焊料在消费类电子产品组装的波峰焊工艺中使用的可靠性,同时研究并比较Sn-Ag系列焊料与SnAgCu系列焊料在回流焊工艺使用的情况。结果表明,Sn-Cu共晶焊料在消费类电子产品组装的波峰焊工艺中完全可以取代Sn-Ag-Cu系列焊料,同时满足使用要求;而同样技术成熟的Sn-Ag共晶焊料也完全可以取代SnAgCu系列焊料在回流焊工艺使用,焊点的可靠性与成本可以媲美SnAgCu焊料。而且该二元合金在使用维护以及回收利用方面具有相当的优势。 相似文献