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1.
波峰焊及再流焊无铅焊点组织演变规律的研究 总被引:6,自引:1,他引:5
以电子封装线上的波峰焊无铅焊点Sn-0.7Cu/Cu、回流焊无铅焊点Sn-3Ag-0.5Cu/Cu为对象,研究了150 ℃时效过程中无铅焊点处金属间化合物(IMC)、焊料合金组织的演化规律及界面处金属间化合物生长的动力学.试验结果表明:两种无铅焊点处IMC层的厚度随着时效时间的延长而增加,IMC层的生长基本上符合抛物线规律,因此IMC层的长大受元素扩散控制;且两种无铅焊点处IMC层的生长速率常数相近,但Sn-0.7Cu焊料中Sn的晶粒尺寸较Sn-3Ag-0.5Cu中的大;长期时效后,在试样的IMC层内发现有孔洞产生. 相似文献
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《电子元件与材料》2017,(11):60-67
通过扫描电镜(SEM)等手段研究了Sn-9Zn/Cu在不同浸焊时间与时效时间等条件下的界面反应及其金属间化合物(IMC)生长行为。结果表明:在浸焊后,Sn-9Zn/Cu钎焊接头界面形成了扇贝状的界面化合物Cu5Zn8,IMC层厚度随着浸焊时间与时效处理时间的增加而增加,未时效处理的焊点界面IMC与铜基板接触的一面较为平直,而与钎料接触的一侧呈现出锯齿状,随着时效时间的增加,界面变得越来越不平整;另外在IMC层与焊料之间产生裂缝现象,分析认为是由于钎料与IMC之间的热膨胀系数差异导致热应力形成裂缝。浸焊600 s后的试样在时效15 d后IMC层与Cu基板接触侧产生了与初始金属间化合物Cu5Zn8不同的三元化合物Cu6(Sn,Zn)5。 相似文献
4.
研究了Sb和稀土化合物的添加对Sn3.0Ag0.5Cu无铅焊料焊接界面金属间化合物层生长的影响。研究结果表明,固态反应阶段界面化合物层的生长快慢排序如下:v(SAC0.4Sb0.1LaB6/Cu)v(SAC0.4Sb/Cu)v(SAC0.1LaB6/Cu)v(SAC/Cu)。计算各种界面IMC生长的激活能Q结果表明,Sn3.0Ag0.5Cu/Cu界面IMC生长的激活能最高,为92.789 kJ,其他焊料合金Sn3.0Ag0.5Cu0.4Sb0.1LaB6/Cu,Sn3.0Ag0.5Cu0.1LaB6/Cu和Sn3.0Ag0.5Cu0.4Sb/Cu界面IMC生长的激活能分别为85.14,84.91和75.57 kJ。在老化温度范围内(≤190℃),Sn3.0Ag0.5Cu0.4Sb0.1LaB6/Cu的扩散系数(D)最小,因而其界面化合物的生长速率最慢。 相似文献
5.
通过回流焊工艺制备了Sn0.7Cu-x Er/Cu(x=0,0.1,0.5)钎焊接头,研究钎焊温度及等温时效时间对接头的界面金属间化合物(IMC)的形成与生长行为的影响。结果表明:Sn0.7Cu钎料中微量稀土Er元素的添加,能有效抑制钎焊及时效过程中界面IMC的形成与生长。在等温时效处理过程中,随着时效时间的延长,界面反应IMC层不断增厚,在相同时效处理条件下,Sn0.7Cu0.5Er/Cu焊点界面IMC层的厚度略小于Sn0.7Cu0.1Er/Cu焊点界面的厚度。通过线性拟合方法,得到Sn0.7Cu0.1Er/Cu和Sn0.7Cu0.5Er/Cu焊点界面IMC层的生长速率常数分别为3.03×10–17 m2/s和2.67×10–17 m2/s。 相似文献
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利用扫描电子显微镜(SEM)和透射电子显微镜(TEM)研究了Sn3.8Ag0.7Cu(Sn37Pb)/Cu焊点在时效过程中的界面金属间化合物(IMC)形貌和成份。结果表明:150℃高温时效50、100、200、500h后,Sn3.8Ag0.7Cu(Sn37Pb)/Cu焊点界面IMC尺寸和厚度增加明显,IMC颗粒间的沟槽越来越小。50h时效后界面出现双层IMC结构,靠近焊料的上层为Cu6Sn5,邻近基板的下层为Cu3Sn。之后利用透射电镜观察了Sn37Pb/Ni和Sn3.8Ag0.7Cu/Ni样品焊点界面,结果显示,焊点界面清晰,IMC晶粒明显。 相似文献
8.
采用SEM观察等手段研究了Sn58BixEr(x=0,0.1,0.5;表示添加质量分数0.01%,0.5%的Er)/Cu钎焊接头界面反应以及在120℃时效过程中金属间化合物(IMC)的生长行为。实验结果表明:Sn58BixEr/Cu钎焊接头IMC层厚度随着钎焊温度的升高而增厚,添加微量的Er能够有效抑制界面IMC的生长。在时效过程中,界面IMC层的厚度随着时效时间的增加而逐渐增厚。通过对实验数据进行拟合,得出120℃时效温度下Sn58Bi0.1Er/Cu和Sn58Bi0.5Er/Cu的IMC层的生长速率常数分别为3.42×10–16 m2/s和2.84×10–16 m2/s。 相似文献
9.
回流焊对SnAgCu焊点IMC及剪切强度的影响 总被引:1,自引:1,他引:0
研究了回流焊次数对Sn-0.3Ag-0.7Cu-xNi/Cu(x=0,0.05)焊点的界面反应及其剪切强度的影响。结果表明:随着回流焊次数的增加,界面金属间化合物(IMC)Cu6Sn5和(Cu1-xNix)6Sn5的厚度均增加。在钎料中添加w(Ni)为0.05%,可有效抑制IMC的生长,与回流焊次数无关。回流焊次数对Sn-0.3Ag-0.7Cu/Cu和Sn-0.3Ag-0.7Cu-0.05Ni/Cu的剪切强度影响都不大,五次回流焊后剪切强度略有下降,剪切强度分别为21MPa和25MPa。发现断裂面部分在钎料中,部分在钎料和IMC之间。 相似文献
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J. Chriaštel’ová L. Rízeková Trnková K. Pocisková Dimová M. Ožvold 《Journal of Electronic Materials》2011,40(9):1956-1961
Small amounts of the rare-earth element Ce were added to the Sn-rich lead-free eutectic solders Sn-3.5Ag-0.7Cu, Sn-0.7Cu,
and Sn-3.5Ag to improve their properties. The microstructures of the solders without Ce and with different amounts (0.1 wt.%,
0.2 wt.%, and 0.5 wt.%) of Ce were compared. The microstructure of the solders became finer with increasing Ce content. Deviation
from this rule was observed for the Sn-Ag-Cu solder with 0.2 wt.% Ce, and for the Sn-0.7Cu eutectic alloy, which showed the
finest microstructure without Ce. The melting temperatures of the solders were not affected. The morphology of intermetallic
compounds (IMC) formed at the interface between the liquid solders and a Cu substrate at temperatures about 40°C above the
melting point of the solder for dipping times from 2 s to 256 s was studied for the basic solder and for solder with 0.5 wt.%
Ce addition. The morphology of the Cu6Sn5 IMC layer developed at the interface between the solders and the substrate exhibited the typical scallop-type shape without
significant difference between solders with and without Ce for the shortest dipping time. Addition of Ce decreased the thickness
of the Cu6Sn5 IMC layer only at the Cu/Sn-Ag-Cu solder interface for the 2-s dipping. A different morphology of the IMC layer was observed
for the 256-s dipping time: The layers were less continuous and exhibited a broken relief. Massive scallops were not observed.
For longer dipping times, Cu3Sn IMC layers located near the Cu substrate were also observed. 相似文献
12.
M. L. Huang T. Loeher D. Manessis L. Boettcher A. Ostmann H. Reichl 《Journal of Electronic Materials》2006,35(1):181-188
A comparative study of solid/solid interfacial reactions of electroless Ni-P (15 at.% P) with lead-free solders, Sn-0.7Cu,
Sn-3.5Ag, Sn-3.8Ag-0.7Cu, and pure Sn, was carried out by performing thermal aging at 150°C up to 1000 h. For pure Sn and
Sn-3.5Ag solder, three distinctive layers, Ni3Sn4, SnNiP, and Ni3P, were observed in between the solder and electroless Ni-P; while for Sn-0.7Cu and Sn-3.8Ag-0.7Cu solders, two distinctive
layers, (CuNi)6Sn5 and Ni3P, were observed. The differences in morphology and growth kinetics of the intermetallic compounds (IMCs) at the interfaces
between electroless Ni-P and lead-free solders were investigated, as well as the growth kinetics of the P-enriched layers
underneath the interfacial IMC layers. With increasing aging time, the coarsening of interfacial Ni3Sn4 IMC grains for pure Sn and Sn-3.5Ag solder was significantly greater than that of the interfacial (CuNi)6Sn5 IMC grains for Sn-0.7Cu and Sn-3.8Ag-0.7Cu solders. Furthermore, the Ni content in interfacial (CuNi)6Sn5 phase slightly increased during aging. A small addition of Cu (0.7 wt.%) resulted in differences in the type, morphology,
and growth kinetics of interfacial IMCs. By comparing the metallurgical aspects and growth kinetics of the interfacial IMCs
and the underneath P-enriched layers, the role of initial Cu and Ag in lead-free solders is better understood. 相似文献
13.
Microstructure, solderability, and growth of intermetallic compounds of Sn-Ag-Cu-RE lead-free solder alloys 总被引:4,自引:0,他引:4
C. M. T. Law C. M. L. Wu D. Q. Yu L. Wang J. K. L. Lai 《Journal of Electronic Materials》2006,35(1):89-93
The near-eutectic Sn-3.5 wt.% Ag-0.7 wt.% Cu (Sn-3.5Ag-0.7Cu) alloy was doped with rare earth (RE) elements of primarily Ce
and La of 0.05–0.25 wt.% to form Sn-3.5Ag-0.7Cu-xRE solder alloys. The aim of this research was to investigate the effect
of the addition of RE elements on the microstructure and solderability of this alloy. Sn-3.5Ag-0.7Cu-xRE solders were soldered
on copper coupons. The thickness of the intermetallic layer (IML) formed between the solder and Cu substrate just after soldering,
as well as after thermal aging at 170°C up to 1000 h, was investigated. It was found that, due to the addition of the RE elements,
the size of the Sn grains was reduced. In particular, the addition of 0.1wt.%RE to the Sn-3.5Ag-0.7Cu solder improved the
wetting behavior. Besides, the IML growth during thermal aging was inhibited. 相似文献
14.
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
15.
Several near-eutectic solders of (1) Sn-3.5Ag, (2) Sn-3.0Ag-0.7Cu, (3) Sn-3.0Ag-1.5Cu, (4) Sn-3.7Ag-0.9Cu, and (5) Sn-6.0Ag-0.5Cu
(in wt.% unless specified otherwise) were cooled at different rates after reflow soldering on the Cu pad above 250°C for 60
sec. Three different media of cooling were used to control cooling rates: fast water quenching, medium cooling on an aluminum
block, and slow cooling in furnace. Both the solder composition and cooling rate after reflow have a significant effect on
the intermetallic compound (IMC) thickness (mainly Cu6Sn5). Under fixed cooling condition, alloys (1), (3), and (5) revealed larger IMC thicknesses than that of alloys (2) and (4).
Slow cooling produced an IMC buildup of thicker than 10 μm, while medium and fast cooling produced a thickness of thinner
than 5 μm. The inverse relationship between IMC thickness and shear strength was confirmed. All the fast- and medium-cooled
joints revealed a ductile mode (fracture surface was composed of the β-Sn phase), while the slow-cooled joints were fractured
in a brittle mode (fracture surface was composed of Cu6Sn5 and Cu3Sn phases). The effect of isothermal aging at 130°C on the growth of the IMC, shear strength, and fracture mode is also reported. 相似文献
16.
The tensile strengths of bulk solders and joint couples of Sn-3.5Ag-0.5Cu, Sn-3.5Ag-0.07Ni, and Sn-3.5Ag-0.5Cu-0.07Ni-0.01Ge
solders and the shear strengths of ball grid array (BGA) specimens, solder-ball-attached Cu/Ni/Au metallized substrates were
investigated. The tensile strength of the bulk is degraded by thermal aging. The Ni-containing solder exhibits lower tensile
strength than Sn-3.5Ag-0.5Cu after thermal aging. However, the Ni-containing solder joints show greater tensile strength than
the Cu/Sn-3.5Ag-0.5Cu/Cu joint. Fracture of the solder joint occurs between the intermetallic compound (IMC) and the solder.
The shear strength and fracture mechanism of BGA specimens are the same regardless of solder composition. 相似文献
17.
The effects of Zn (1 wt.%, 3 wt.%, and 7 wt.%) additions to Sn-3.5Ag solder and various reaction times on the interfacial
reactions between Sn-3.5Ag-xZn solders and Cu substrates a during liquid-state aging were investigated in this study. The composition and morphological
evolution of interfacial intermetallic compounds (IMCs) changed significantly with the Zn concentration and reaction time.
For the Sn-3.5Ag-1Zn/Cu couple, CuZn and Cu6Sn5 phases formed at the interface. With increasing aging time, the Cu6Sn5 IMC layer grew thicker, while the CuZn IMC layer drifted into the solder and decomposed gradually. Cu5Zn8 and Ag5Zn8 phases formed at the interfaces of Sn-3.5Ag-3Zn/Cu and Sn-3.5Ag-7Zn/Cu couples. With increasing reaction time, the Cu5Zn8 layer grew and Cu atoms diffused from the substrate to the solder, which transformed the Ag5Zn8 to (Cu,Ag)5Zn8. The Cu6Sn5 layer that formed between the Cu5Zn8 layer and Cu was much thinner at the Sn-3.5Ag-7Zn/Cu interface than at the Sn-3.5Ag-3Zn/Cu interface. Additionally, we measured
the thickness of interfacial IMC layers and found that 3 wt.% Zn addition to the solder was the most effective for suppressing
IMC growth at the interfaces. 相似文献
18.
This study investigates the microstructural evolution and kinetics of intermetallic (IMC) formation in Sn-3.5Ag-0.7Cu lead-free solder joints with different percentages of Sb element, namely, Sn-3.5Ag-0.7Cu-xSb (x=0, 0.2, 0.5, 0.8, 1.0, 1.5, and 2.0). To investigate the elemental interdiffusion and growth kinetics of IMC formation, isothermal aging test is performed at temperatures of 100/spl deg/C, 150/spl deg/C, and 190/spl deg/C, respectively. Scanning electron microscope (SEM) is used to measure the thickness of intermetallic layer and observe the microstructural evolution of solder joint. The IMC phases are identified by EDX and XRD. Results show that some of the antimony powders are dissolved in the /spl beta/-Sn matrix (Sn-rich phase), some of them participate in the formation of Ag/sub 3/(Sn,Sb) and the rest dissolves in the Cu/sub 6/Sn/sub 5/ IMC layer. There is a significant drop in IMC thickness when Sb is added to 0.8 wt%. Over this amount the thickness of the IMC increases slightly again. The activation energy and growth rate of the IMC formation are determined. Results reveal that adding antimony in Sn-3.5Ag-0.7Cu solder system can increase the activation energy, and thus reduce the atomic diffusion rate, so as to inhibit the excessive growth of the IMC. The solder joint containing 0.8 wt% antimony has the highest activation energy. SEM images reveal that the number of small particles precipitating in the solder matrix increases with the increase in Sb composition. Based on the observation of the microstructural evolution of the solder joints, a grain boundary pinning mechanism for inhibition of the IMC growth due to Sb addition is proposed. 相似文献
19.
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
20.
This study aims to investigate the shear and tensile impact strength of solder ball attachments. Tests were conducted on Ni-doped and non-Ni-doped Sn-0.7wt.% Cu, Sn-37wt.% Pb and Sn-3.0wt.% Ag-0.7wt.% Cu solder ball grid arrays (BGAs) placed on Cu substrates, which were as-reflowed and aged, over a wide range of displacement rates from 10 to 4000 mm/s in shear and from 1 to 400 mm/s in tensile tests. Ni additions to the Sn-0.7wt.% Cu solders has slowed the growth of the interface intermetallic compounds (IMCs) and made the IMC layer morphology smooth. As-reflowed Ni-doped Sn-0.7wt.% Cu BGA joints show superior properties at high speed shear and tensile impacts compared to the non-Ni-doped Sn-0.7wt.% Cu and Sn-3.0wt.% Ag-0.7wt.% Cu BGAs. Sn-3.0wt.% Ag-0.7wt.% Cu BGAs exhibit the least resistance in both shear and tensile tests among the four compositions of solders, which may result from the cracks in the IMC layers introduced during the reflow processes. 相似文献