共查询到20条相似文献,搜索用时 15 毫秒
1.
During the reflowing of Sn-9Zn solder ball grid array (BGA) packages with Au/Ni/Cu and Ag/Cu pads, the surface-finished Au
and Ag film dissolved rapidly and reacted with the Sn-9Zn solder to form a γ3-AuZn4/γ-Au7Zn18 intermetallic double layer and ε-AgZn6 intermetallic scallops, respectively. The growth of γ3-AuZn4 is prompted by further aging at 100°C through the reaction of γ-Au7Zn18 with the Zn atoms dissolved from the Zn-rich precipitates embedded in the β-Sn matrix of Sn-9Zn solder BGA with Au/Ni/Cu
pads. No intermetallic compounds can be observed at the solder/pad interface of the Sn-9Zn BGA specimens aged at 100°C. However,
after aging at 150°C, a Ni4Zn21 intermetallic layer is formed at the interface between Sn-9Zn solder and Ni/Cu pads. Aging the immersion Ag packages at 100°C
and 150°C caused a γ-Cu5Zn8 intermetallic layer to appear between ε-AgZn6 intermetallics and the Cu pad. The scallop-shaped ε-AgZn6 intermetallics were found to detach from the γ-Cu5Zn8 layer and float into the solder ball. Accompanied with the intermetallic reactions during the aging process of reflowed Sn-9Zn
solder BGA packages with Au/Ni/Cu and Ag/Cu pads, their ball shear strengths degrade from 8.6 N and 4.8 N to about 7.2 N and
2.9 N, respectively. 相似文献
2.
Yu-Chih Liu Wei-Hong Lin Hsiu-Jen Lin Tung-Han Chuang 《Journal of Electronic Materials》2006,35(1):147-153
During the reflow process of Sn-8Zn-20In solder joints in the ball grid array (BGA) packages with Au/Ni/Cu and Ag/Cu pads,
the Au and Ag thin films react with liquid solder to form γ3-AuZn4/γ-Au7Zn18 and ε-AgZn6 intermetallics, respectively. The γ3/γ intermetallic layer is prone to floating away from the solder/Ni interface, and the appearance of any interfacial intermetallics
cannot be observed in the Au/Ni surface finished Sn-8Zn-20In packages during further aging treatments at 75°C and 115°C. In
contrast, ε-CuZn5/γ-Cu5Zn8 intermetallics are formed at the aged Sn-8Zn-20In/Cu interface of the immersion Ag BGA packages. Bonding strengths of 3.8N
and 4.0N are found in the reflowed Sn-8Zn-20In solder joints with Au/Ni/Cu and Ag/Cu pads, respectively. Aging at 75°C and
115°C gives slight increases of ball shear strength for both cases. 相似文献
3.
Ching-Feng Yang Sinn-Wen Chen Kuan-Hsien Wu Tsung-Shune Chin 《Journal of Electronic Materials》2007,36(11):1524-1530
Sn-Zn-Bi alloys are promising Pb-free solders. Interfacial reactions between the Sn-8wt.%Zn-3wt.%Bi (Sn-13.80at.%Zn-1.62at.%Bi)
alloy and the Cu, Ag, and Ni substrates are examined. Two different kinds of substrates, the bulk plate and the electroplating
layer, are used, and the reactions are carried out at 250°C and 220°C. Although the Zn content is only 13.8 at.%, two Zn-Cu
compounds, γ-Cu5Zn8 and ε-CuZn5 phases, are formed in the Sn-13.80at.%Zn-1.62at.%Bi/Cu couples. The ε-CuZn5 phase is scallop shaped, and the γ-Cu5Zn8 phase is planar. In the Sn-13.80at.%Zn-1.62at.%Bi/Ag couples, three Zn-Ag compounds are observed, and they are ε-AgZn3, γ-Ag5Zn8, and ζ-AgZn phases. In the Sn-13.80at.%Zn-1.62at.%Bi/Ni couples, a Zn-Ni compound, γ-Ni5Zn21 phase, is formed. Similar results are found in the couples prepared with an electroplating layer: the reaction phases are
the same, but the growth rates are different. 相似文献
4.
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
5.
Solidification and interfacial reactions in Sn-57 wt.%Bi-(Co)/Cu couples are investigated. The addition of 0.05 wt.% Co and
0.5 wt.% Co and changes between 2 g and 20 mg solder sizes have no significant effects on the undercooling of Sn-57 wt.%Bi
solders. Both η-Cu6Sn5 and ε-Cu3Sn phases are formed in Sn-57 wt.%Bi/Cu couples reacted at 80°C, 100°C, and 100°C, whereas only η-Cu6Sn5 is formed at 160°C. The formation of ε-Cu3Sn is suppressed and only η-Cu6Sn5 is found in the couple with 0.05 wt.% Co and 0.5 wt.% Co addition in Sn-57 wt.%Bi solder. Both the growth rate of η-Cu6Sn5 and the dissolution rate of the Cu substrate increase with Co addition. The morphology of η-Cu6Sn5 is also altered with Co addition, becoming a porous structure with solder trapped in the voids. 相似文献
6.
Yee-Wen Yen Weng-Ting Chou Yu Tseng Chiapyng Lee Chun-Lei Hsu 《Journal of Electronic Materials》2008,37(1):73-83
This study investigates the dissolution behavior of the metallic substrates Cu and Ag and the intermetallic compound (IMC)-Ag3Sn in molten Sn, Sn-3.0Ag-0.5Cu, Sn-58Bi and Sn-9Zn (in wt.%) at 300, 270 and 240°C. The dissolution rates of both Cu and
Ag in molten solder follow the order Sn > Sn-3.0Ag-0.5Cu >Sn-58Bi > Sn-9Zn. Planar Cu3Sn and scalloped Cu6Sn5 phases in Cu/solders and the scalloped Ag3Sn phase in Ag/solders are observed at the metallic substrate/solder interface. The dissolution mechanism is controlled by
grain boundary diffusion. The planar Cu5Zn8 layer formed in the Sn-9Zn/Cu systems. AgZn3, Ag5Zn8 and AgZn phases are found in the Sn-9Zn/Ag system and the dissolution mechanism is controlled by lattice diffusion. Massive
Ag3Sn phases dissolved into the solders and formed during solidification processes in the Ag3Sn/Sn or Sn-3.0Ag-0.5Cu systems. AgZn3 and Ag5Zn8 phases are formed at the Sn-9Zn/Ag3Sn interface. Zn atoms diffuse through Ag-Zn IMCs to form (Ag, Zn)Sn4 and Sn-rich regions between Ag5Zn8 and Ag3Sn. 相似文献
7.
Eutectic Sn-Zn-Al solder alloy was used [composition: 91Sn-9(5Al-Zn)] to investigate the effects of dipping parameters such
as the temperature, rate and time dipping on the adhesion strength between solder and substrate using dimethylammonium chloride
(DMAHCl) flux. The optimum conditions for the highest adhesion strength (about 8 MPa) were determined as dipping at 350°C,
and a rate of 10.8∼11.8 mm/s for 5∼7.5 min. A poor solder coating was obtained as dipped at 250°C. Some defects by non-wetting
were found as dipped at a slow rate (slower than 8.2 mm/s). Quite different from the most tin-based solders for copper substrate,
γ-Cu5Zn8 intermetallic compound particles were found by x-ray diffraction (XRD) analysis at the interface of solder and substrate
as dipped at 300°C after pull-off test by etching out the unreacted solder layer. The morphology of the intermetallic compound
formed was observed by scanning electron microscopy (SEM). The elements of Al (near Cu), Zn (near Sn) are enriched at the
interface of solder and copper substrate as determined by the line scanning and mapping analysis. 相似文献
8.
T. H. Chuang H. M. Wu M. D. Cheng S. Y. Chang S. F. Yen 《Journal of Electronic Materials》2004,33(1):22-27
Intermetallic compounds formed during the soldering reactions between Sn-3.5Ag and Cu at temperatures ranging from 250°C to
375°C are investigated. The results indicate that scallop-shaped η-Cu6(Sn0.933 Ag0.007)5 intermetallics grow from the Sn-3.5Ag/Cu interface toward the solder matrix accompanied by Cu dissolution. Following prolonged
or higher temperature reactions, ɛ-Cu3 (Sn0.996 Ag0.004) intermetallic layers appear behind the Cu6(Sn0.933 Ag0.007)5 scallops. The growth of these interfacial intermetallics is governed by a kinetic relation: ΔX=tn, where the n values for η and ɛ intermetallics are 0.75 and 0.96, respectively. The mechanisms for such nonparabolic growth
of interfacial intermetallics during the liquid/solid reactions between Sn-3.5Ag solders and Cu substrates are probed. 相似文献
9.
Yoshikazu Takaku Lazuardi Felicia Ikuo Ohnuma Ryosuke Kainuma Kiyohito Ishida 《Journal of Electronic Materials》2008,37(3):314-323
Chemical reactions between Cu substrates and Zn-Al high-temperature solder alloys, Zn-4Al and Zn-4Al-1Cu (mass%), at temperatures
ranging from 420°C to 530°C were experimentally investigated by a scanning electron microscope using backscattered electrons
(SEM-BSE) and an electron probe microanalyzer (EPMA). Intermediate phases (IMPs), β(A2) or β′(B2), γ(D82), and ε(A3) phases formed and grew during the soldering and aging treatments. The consumption rate of the IMP for Cu substrates
is described by the square root of t in both the alloys, while the additional Cu in the molten Zn-Al alloy slightly suppresses the consumption of Cu substrates.
The growth of IMPs during soldering treatment is controlled by the volume diffusion of constituent elements, and its activation
energy increases in the order of Q
ε < Q
γ < Q
β. In view of the aging process, the growth of IMPs is considered to be controlled by the volume diffusion. In particular,
the layer thickness of γ rapidly grows over 200°C, although the thickness of the β layer grows very slowly. 相似文献
10.
The intermetallic compounds (IMCs) formed at the interface between the Sn-9Zn-1.5Ag-0.5Bi lead-free solder alloy and unfluxed
Cu substrate have been investigated by x-ray diffraction, optical microscopy, scanning electron microscopy (SEM), and energy-dispersive
spectrometry (EDS). The melting point and melting range of the Sn-9Zn-1.5Ag-0.5Bi solder alloy are determined as 195.9°C and
10°C, respectively, by differential scanning calorimetry (DSC). Cu6Sn5 and Cu5Zn8 IMCs are formed between the Sn-9Zn-1.5Ag-0.5Bi/unfluxed Cu substrate wetted at 250°C for 10 sec. The interfacial adhesion
strength changes from 10.27±0.68 MPa to 8.58±0.59 MPa when soldering time varies from 10 sec to 30 sec at 250°C. 相似文献
11.
The thermal property of lead-free Sn-8.55Zn-1Ag-XAl solder alloys and their wetting interaction with Cu 总被引:1,自引:0,他引:1
The wetting behaviors between the quaternary Sn-8.55Zn-1Ag-XAl solder alloys and Cu have been investigated with the wetting
balance method. The Al contents, x, of the quaternary solder alloys investigated were 0.01–0.45 wt.%. The results of differential
scanning calorimeter (DSC) analysis indicate that the solders exhibit a solid-liquid coexisting range of about 7–10°C. The
solidus temperature of the quaternary Sn-8.55Zn-1Ag-XAl solder alloys is about 198.2°C, while the liquidus temperatures are
205–207°C. The experimental results showed that the wettability of the Sn-8.55Zn-1Ag-XAl solder alloys is improved by the
addition of Al. The mean maximum wetting force of the solders with Cu is within 0.75–1.18 mN and the mean wetting time is
around 1.0–1.1 sec, better than the ∼1.3 sec of eutectic Sn-9Zn and Sn-8.55Zn-1Ag solder alloys. The addition of Al also depresses
the formation of ε-Ag-Zn compounds at the interface between Sn-8.55Zn-1Ag-XAl solders and copper. 相似文献
12.
We have studied two kinds of solder reactions between eutectic SnPb and Cu. The first is wetting reaction above the melting
point of the solder, and the second is solid state aging below the melting point of the solder. In wetting reaction, the intermetallic
compound (IMC) formation has a scallop-type morphology. There are channels between the scallops. In solid state aging, the
IMC formation has a layer-type morphology. There are no channels but grain boundaries between the IMC grains. Why scallops
are stable in wetting reactions has been an unanswered question of fundamental interest. We have confirmed that the scallop-type
morphology is stable in wetting reaction by re-wetting the layer-type IMC by molten eutectic SnPb solder. In less than 1 min,
a layer-type Cu6Sn5 is transformed back to scallops by the molten solder at 200 C. In analyzing these reactions, we conclude that the scallop-type
morphology is thermodynamically stable in wetting reaction, but the layer-type morphology is thermodynamically stable in solid
state aging, due to minimization of interfacial and grain boundary energies. 相似文献
13.
C. M. L. Wu M. L. Huang J. K. L. Lai Y. C. Chan 《Journal of Electronic Materials》2000,29(8):1015-1020
A new lead free alloy, Sn-6Bi-2Ag-0.5Cu, has been developed by mechanical alloying and has great potential as a lead-free
solder system. Initial trials on the manufacture of solder joints with this alloy revealed that a high quality bond with copper
could be formed. Its melting range of 193.87°C to 209.88°C is slightly higher than that of eutectic tin-lead solder. Examination
of the microstructure of the as-soldered joints revealed that it mainly consists of small bismuth (1 μm to 2 μm) and Ag3Sn (1 μm) particles finely dispersed in a nearly pure tin matrix with a small amount of η-Cu6Sn5 particles. The Cu-Sn intermetallic compound (IMC) layer formed at solder-copper interface is the η-Cu6Sn5 phase with grain size of 2 μm. The shear strength of the solder joint is higher than that of Sn-37Pb or Sn-3.5Ag. Under shear
loading, fracture occurred at IMC layer-solder interface as well as in the bulk of solder. 相似文献
14.
Wetting interaction between Sn-Zn-Ag solders and Cu 总被引:4,自引:0,他引:4
The wetting interaction of Sn-(7.1–9)Zn-(0–3)Ag solders with Cu was investigated from 230°C to 300°C. The wetting time, wetting
forces, and activation energy of the wetting reaction were studied. The wetting time decreases with increasing temperature
and increases with Ag content. The wetting force exhibits a disproportional correlation to temperature rise, while no trend
was observed with respect to Ag content. The wetting behavior was ascribed to the interaction between Cu and Zn. The AgZn3 compound was formed at the interface when the solder contains 0.3% Ag and above, while it was formed within the bulk solder
at 2% Ag and above. 相似文献
15.
Effects of Ce and La Additions on the Microstructure and Mechanical Properties of Sn-9Zn Solder Joints 总被引:1,自引:0,他引:1
The effects of rare-earth elements on the microstructure and mechanical properties of Sn-9Zn alloys and solder joints in ball
grid array packages with Ni/Au(ENIG) surface finishes have been investigated. Metallographic observations showed that (Ce0.8Zn0.2)Sn3 and (La0.9Zn0.1)Sn3 intermetallic compounds appeared in the solder matrix of Sn-9Zn-0.5Ce and Sn-9Zn-0.5La alloys, respectively. Both fiber-
and hillock-shaped tin whiskers were inhibited in the Sn-9Zn-0.5Ce solder, while tin fibers were still observed on the surface
of oxidized (La0.9Zn0.1)Sn3 intermetallics in Sn-9Zn-0.5La after air exposure at room temperature. Mechanical testing indicated that the tensile strength
of Sn-9Zn alloys doped with Ce and La increased significantly, and the elongation decreased, in comparison with the undoped
Sn-9Zn. The bonding strengths of the as-reflowed Sn-9Zn-0.5Ce and Sn-9Zn-0.5La solder joints were also improved. However,
aging treatment at 100°C and 150°C caused degradation of ball shear strength in all specimens. During the reflowing and aging
processes, AuZn8 intermetallic phases appeared at the interfaces of all solder joints. In addition, Zn-rich phases were observed to migrate
from the solder matrix to the solder/pad interfaces of the aged specimens. 相似文献
16.
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
17.
The intermetallic compounds formed in Sn3Ag0.5Cu and Sn3Ag0.5Cu0.06Ni0.01Ge solder BGA packages with Ag/Cu pads are investigated.
After reflow, scallop-shaped η-Cu6Sn5 and continuous planar η-(cu0.9Ni0.1)6Sn5 intermetallics appear at the interfaces of the Sn3Ag0.5Cu and Sn3Ag0.5Cu0.06Ni0.01Ge solder joints, respectively. In the
case of the Sn3Ag0.5Cu specimens, an additional ε-Cu3Sn intermetallic layer is formed at the interface between the η-Cu6Sn5 and Cu pads after aging at 150°C, while the same type of intermetallic formation is inhibited in the Sn3Ag0.5Cu0.06Ni0.01Ge
packages. In addition, the coarsening of Ag3Sn precipitates also abates in the solder matrix of the Sn3Ag0.5Cu0.06Ni0.01Ge packages, which results in a slightly higher
ball shear strength for the specimens. 相似文献
18.
In this study, solid-state interfacial reactions between Ag and Sn-Zn alloys with varying Zn content (0.1 wt.% to 9 wt.%) were investigated at 170°C. The reaction couples were prepared by electroplating Ag on the Sn-Zn alloy to avoid dissolution of Ag into the molten solder during soldering. The Zn content greatly influenced the reaction products and the interfacial microstructures. When the Zn content was less than 4 wt.%, Ag3Sn and AgZn layers were simultaneously formed. Notably, Zn could actively diffuse through the Ag3Sn layer and react with Ag to form the AgZn phase. With the proceeding reaction, small α-Ag particulates were produced within the AgZn phase. With 9 wt.% Zn, the dominant reactions formed Ag5Zn8 and AgZn layers. The interfacial microstructure evolved significantly with reaction time. Interface instability due to Zn depletion in the solder resulted in massive spalling of the Ag5Zn8 layer. The Ag3Sn phase was then produced next to the AgZn layer. Moreover, another reaction couple, Sn-9 wt.%Zn/Sn(15 μm)/Ag, was prepared, in which fast interdiffusion between Zn and Ag across the Sn layer was demonstrated due to the strong chemical affinity of Zn. 相似文献
19.
In this study, we used microstructure evolution and electron microprobe analysis (EPMA) to investigate the interfacial reactions
in Sn-Zn and Sn-Zn-Al solder balls with Au/Ni surface finish ball-grid-array (BGA) bond pad over a period of isothermal aging
at 150°C. During reflow, Au dissolved into the solder balls and reacted with Zn to form γ-Au3Zn7 and γ2-AuZn3. As aging progressed, γ and γ2 transformed into γ3-AuZn4. Finally, Zn precipitated out next to γ3-AuZn4. The Zn reacted with the Ni layer to form Ni5Zn21. A thin layer (Al, Au, Zn) intermetallic compound (IMC) formed at the interface of the Sn-Zn-Al solder balls, inhibiting
the reaction of Ni with Zn. Even after 50 days of aging, no Ni5Zn21 was observed. Instead, fine (Al, Au, Zn) particles similar to Al2 (Au, Zn) in composition formed and remained stable in the solder. The lower ball shear strength corresponded with the brittle
fracture morphology in Sn-Zn-Al solder ball samples. 相似文献
20.
Morphology of intermetallic compounds formed between lead-free Sn-Zn based solders and Cu substrates
The morphologies of intermetallic compounds formed between Sn-Zn based solders and Cu substrates were investigated in this
study. The investigated solders were Sn-9Zn, Sn-8.55Zn-0.45Al, and Sn-8.55Zn-0.45Al-0.5Ag. The experimental results indicated
that the Sn-9Zn solder formed Cu5Zn8 and CuZn5 compounds on the Cu substrate, while the Al-containing solders formed the Al4.2Cu3.2Zn0.7 compound. The addition of Ag to the Sn-8.55Zn-0.45Al solder resulted in the formation of the AgZn3 compound at the interface between the Al4.2Cu3.2Zn0.7 compound and the solder. Furthermore, it was found that the cooling rate of the specimen after soldering had an effect on
the quantity of AgZn3 compound formed at the interface. The AgZn3 compound formed with an air-cooling condition exhibited a rougher surface and larger size than with a water-quenched condition.
It was believed that the formation of the AgZn3 compound at the interface occurs through heterogenous nucleation during solidification. 相似文献