共查询到20条相似文献,搜索用时 31 毫秒
1.
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
2.
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
3.
Yoshikazu Takaku Komei Makino Keita Watanabe Ikuo Ohnuma Ryosuke Kainuma Yasushi Yamada Yuji Yagi Ikuo Nakagawa Takashi Atsumi Kiyohito Ishida 《Journal of Electronic Materials》2009,38(1):54-60
The Zn-Al(-Cu) eutectic alloys (melting point 381°C) are candidates for use as Pb-free high-temperature solders as a substitute
for Pb-based solders, which are suitable for severe working environments such as the engine room of hybrid vehicles equipped
with an inverter system as well as a heat engine. In this study, the interfacial reaction between Zn-Al(-Cu) alloys and the
Ni substrate during soldering, aging, and thermal cycling was investigated. Semiconductor chips and Ni substrates were soldered
with Zn-Al(-Cu) alloys at various temperatures under a nitrogen atmosphere. The soldered assemblies were then heat-treated
at 200°C and 300°C to examine the microstructural evolution at the soldered interface. The effect of severe thermal cycles
between −40°C and 250°C in air on the microstructure and fracture behavior at the solder joint was investigated. Even after
a 1000-cycle test, the thickness of the Al3Ni2 layer formed at the interface between the Zn-Al-based solder and the Ni substrate, which is responsible for the damage of
the soldered assemblies, was quite small. 相似文献
4.
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
5.
We have studied the microstructure of the Sn-9Zn/Cu joint in soldering at temperatures ranging from 230°C to 270°C to understand
the growth of the mechanism of intermetallic compound (IMC) formation. At the interface between the Sn-9Zn solder and Cu,
the results show a scallop-type ε-CuZn4 and a layer-type γ-Cu5Zn8, which grow at the interface between the Sn-9Zn solder and Cu. The activation energy of scallop-type ε-CuZn4 is 31 kJ/mol, and the growth is controlled by ripening. The activation energy of layer-type γ-Cu5Zn8 is 26 kJ/mol, and the growth is controlled by the diffusion of Cu and Zn. Furthermore, in the molten Sn-9Zn solder, the results
show η-CuZn grains formed in the molten Sn-9Zn solder at 230°C. When the soldering temperature increases to 250°C and 270°C,
the phase of IMCs is ε-CuZn4. 相似文献
6.
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
7.
For the application of In-49Sn solder in bonding recycled-sputtering targets to Cu back plates, the intermetallic compounds
formed at the In-49Sn/Cu interface are investigated. Scanning electron microscopy (SEM) observations show that the interfacial
intermetallics consist of a planar layer preceded by an elongated scalloped structure. Electron-probe microanalyzer analyses
indicate that the chemical compositions of the planar layer and the scalloped structure are Cu74.8In12.2Sn13.0 and Cu56.2In20.1Sn23.7, respectively, which correspond to the ε-Cu3(In,Sn) and η-Cu6(In,Sn)5 phases. Kinetics analyses show that the growth of both intermetallic compounds is diffusion controlled. The activation energies
for the growth of η- and ε-intermetallics are calculated to be 28.9 kJ/mol and 186.1 kJ/mol. Furthermore, the formation mechanism of intermetallic compounds
during the In-49Sn/Cu soldering reaction is clarified by marking the original interface with a Ta-thin film. Wetting tests
are also performed, which reveal that the contact angles of liquid In-49Sn drops on Cu substrates decline to an equilibrium
value of 25°C. 相似文献
8.
The distribution of Si, Fe, and Cu in FeSi2 alloys, with or without the addition of Cu, were studied by electron probe microanalysis (EPMA). Alloys were prepared by
slow solidification from the melt. Without Cu addition, both ε- and α-phases were clearly observed, and a β-phase surrounding
the ε-phase was additionally observed after in situ annealing at 950°C for 12 h. With inclusion of 0.5 at.% Cu, the eutectoid reaction (α → β + Si) was enhanced greatly. Only
0.01 at.% Cu was dissolved into the ε-phase, with the excess Cu atoms being largely found at the outer edge of the ε-phase.
Ex situ annealing at 950°C for 12 h greatly changed the distribution of Si, Fe, and Cu. The ε-phase changed its Si/Fe atomic ratio
from 1.470 to 1.907, indicating an early stage of the peritectoid reaction (ε + α → β) and/or the subsequent reaction (ε + Si → β),
with an increase in the Cu content up to 0.04 at.%. The size of this new phase was smaller than the original ε-phase, and
this new phase was surrounded by a shell of Si/Fe with an atomic ratio of 0.727 to 1.788 and a Cu content of 0.01 at.% to
0.11 at.%. In situ annealing under the same condition yielded different results: a large amount of Si segregates from the α-phase matrix, leaving
a Si/Fe atomic ratio of only 0.506 to 0.530. The peritectoid reaction of the ε-phase was found to depend on the Cu content.
For the ε-phase with undetectable levels of Cu, the Si/Fe atomic ratio remained at 0.954 to 0.998, but this ratio decreased
with increasing Cu content to 0.55 at 2.20 at.% Cu. A plot of at.% Cu versus Si/Fe atomic ratio revealed a local minimum at
the ε-phase and expectedly at both the β- and α-phases. Nonstoichiometric structures (neither α-, β- nor ε-phases) seemed
to have higher at.% Cu compared with those with the closest Si/Fe composition. 相似文献
9.
Chih-Yao Liu Ying-Ru Chen Wang-Long Li Min-Hsiung Hon Moo-Chin Wang 《Journal of Electronic Materials》2007,36(11):1531-1535
The electrochemical properties of the joints formed between Sn-9Zn-1.5Ag-1Bi alloys and Cu substrates in a 3.5 wt.% NaCl solution
have been investigated by potentiodynamic polarization, X-ray diffraction, and scanning electron microscopy. For the Sn-9Zn-1.5Ag-1Bi/Cu
joints in a 3.5 wt.% NaCl solution, corrosion current (I
corr), corrosion potential (E
corr) and corrosion resistance (R
p) are 2.46 × 10−6 A/cm2, −1.18 V, and 7.54 × 103 Ωcm2, respectively. Cu6Sn5, Cu5Zn8, and Ag3Sn are formed at the interface between the Sn-9Zn-1.5Ag-xBi solder alloy and Cu substrate. The corrosion products of ZnCl2, SnCl2 and ZnO are formed at the Sn-9Zn-1.5Ag-xBi/Cu joints after polarization in a 3.5 wt.% NaCl solution. Pits are also formed on the surface of the solder alloys. 相似文献
10.
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
11.
This study investigates the effects of various reaction times and Cu contents on the interfacial reactions between Sn-9Zn-xCu alloys and Ni substrates. After aging at 255°C for 1 h to 3 h, the Ni5Zn21 and Cu5Zn8 phases formed at the interface of Sn-9Zn/Ni and Sn-9Zn-1wt.%Cu/Ni couples, respectively. The (Ni,Zn)3Sn4 phase was found in the Sn-9Zn-4wt.%Cu/Ni couple, and the (Cu,Ni)6Sn5 and Cu6Sn5 phases formed, respectively, in the Sn-9Zn-7wt.%Cu/Ni and Sn-9Zn-10wt.%Cu/Ni couples. As the reaction time was increased
from 5 h to 24 h, the (Cu5Zn8 + Ni5Zn21) phases replaced the Cu5Zn8 phase to form in the Sn-9Zn-1wt.%Cu/Ni couple; the (Ni,Zn)3Sn4 phase formed in the Sn-9Zn-4wt.%Cu/Ni couple, and (CuZn + Cu6Sn5) formed in the Sn-9Zn-10wt.%Cu alloys. Experimental results indicate that intermetallic compound (IMC) formation in Sn-9Zn-xCu/Ni couples changes dramatically with reaction time and Cu content. The Sn-Zn-Ni, Sn-Cu-Ni, and Sn-Zn-Cu ternary isothermal
sections greatly help us to understand the IMC evolutions in the Sn-9Zn-xCu/Ni couples. 相似文献
12.
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
13.
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
14.
C. Leinenbach F. Valenza D. Giuranno H. R. Elsener S. Jin R. Novakovic 《Journal of Electronic Materials》2011,40(7):1533-1541
Au-Ge-based alloys are interesting as novel high-temperature lead-free solders because of their low melting point, good thermal
and electrical conductivity, and high corrosion resistance. In the present work, the wetting and soldering behavior of the
eutectic Au-28Ge (at.%) alloy on Cu and Ni substrates have been investigated. Good wetting on both substrates with final contact
angles of 13° to 14° was observed. In addition, solder joints with bond shear strength of 30 MPa to 35 MPa could be produced
under controlled conditions. Cu substrates exhibit pronounced dissolution into the Au-Ge filler metal. On Ni substrates, the
NiGe intermetallic compound was formed at the filler/substrate interface, which prevents dissolution of Ni into the solder.
Using thin filler metal foils (25 μm), complete consumption of Ge in the reaction at the Ni interface was observed, leading to the formation of an almost pure
Au layer in the soldering zone. 相似文献
15.
The creep behavior of Sn-1Ag-0.5Cu, Sn-2.5Ag-1Cu and Sn-4Ag-0.5Cu ball grid array (BGA) solder balls and 99.99% pure polycrystalline
bulk Sn was studied using impression creep and related to the microstructure. Sn-Ag-Cu solders generally consist of primary
dendrites/grains of β-Sn, and a eutectic microconstituent comprising fine Ag3Sn and Cu6Sn5 particles in β phase. With increasing concentrations of Ag and Cu in the alloy, the proportion of the eutectic microconstituent in relation
to the primary β phase increases. In pure Sn and Sn-1Ag-0.5Cu, the β grains form the continuous matrix, whereas in Sn-2.5Ag-1Cu and Sn-4Ag-0.5Cu, the eutectic microconstituent forms a continuous
network around the β grains, which form isolated islands within the eutectic. The steady-state creep behavior of the alloys was dominated by the
response of the continuous microstructural constituent (β-Sn or solid solution β for pure Sn and Sn-1Ag-0.5Cu, and the eutectic microconstituent for Sn-2.5Ag-0.5Cu and Sn-4Ag-0.5Cu). In general, the steady-state
creep rate decreased with increasing alloy content, and in particular, the volume fraction of Ag3Sn and Cu6Sn5 precipitates. The rate-limiting creep mechanism in all the materials investigated here was core diffusion controlled dislocation
climb. However, subtle changes in the stress exponent n and activation energy Q were observed. Pure Sn shows n = 5, Q = 42 kJ/mol, Sn-1Ag-0.5Cu shows n = 5, Q = 61 kJ/mol, whereas both Sn-2.5Ag-1Cu and Sn-4Ag-0.5Cu show n = 6 and Q = 61 kJ/mol. Rationalizations for the observed changes of n and Q are provided, based on the influence of the microstructure and the solute concentrations. 相似文献
16.
The reliability of adhesion strength of the Sn-9Zn-1.5Ag-0.5Bi/Cu during isothermal aging has been investigated. Due to the
growth and decomposition of the intermetallic compound (IMC), the adhesion strength varies with aging at 150°C from 100, 400,
and 700–1,000 h as wetted at 250°C for 60 sec. The IMC layers are determined at the Sn-9Zn-1.5Ag-0.5Bi/Cu interface by an
x-ray diffractometer (XRD), an optical microscope (OM), a scanning electron microscope (SEM), an energy-dispersive spectroscope
(EDS), and a transmission electron microscope (TEM). The adhesion strength has been investigated by the pull-off test. The
results show that the Cu6Sn5, Cu5Zn8, and Ag3Sn IMCs are identified at the Sn-9Zn-1.5Ag-0.5Bi/Cu interface as aging. The adhesion strengths are 12.44±0.58, 8.57±0.43,
5.50±0.78, 4.32±0.78, and 3.32±0.43 MPa for aging times of 0 h, 100 h, 400 h, 700 h, and 1,000 h, respectively. 相似文献
17.
Adhesion strength of the Sn-9Zn-xAg/Cu interface 总被引:5,自引:0,他引:5
The adhesion strength of the Sn-9Zn-xAg/Cu interface was studied. The strength increased from 3.34±0.68 MPa to 7.79±0.57 MPa
and from 4.75±1.04 MPa to 10.70±0.75 MPa for the Sn-9Zn-1.5Ag/Cu and Sn-9Zn-2.5Ag/Cu interfaces, respectively, as soldered
at 250°C for the soldering time from 10 sec to 30 sec. However, the strength decreased from 8.11±0.72 MPa to 5.61±0.36 MPa
for the Sn-9Zn-3.5Ag/Cu interface at 250°C for 10–30 sec. Both prolonging soldering time and raising temperature are beneficial
for the adhesionstrength enhancement of the Sn-9Zn-1.5Ag/Cu and Sn-9Zn-2.5Ag/Cu interfaces because of the increment of wettability,
but it is detrimental to the Sn-9Zn-3.5Ag/Cu interface because of microvoid formation. 相似文献
18.
The growth behavior of the intermetallic compounds that formed at the interfaces between Sn-Ag-Bi-In solders and Cu substrates
during solid-state aging is investigated. The compositions of the intermetallic compounds are Cu3(Sn,In) near the Cu substrates and Cu6(Sn,In)5 near the solders; very little Bi or Ag was dissolved in the compounds. The aging temperatures were 120°C, 150°C, and 180°C
for 5 days, 10 days, 20 days, and 40 days. The change in the morphology of Cu6(Sn,In)5 from scallop type to layer type was prominent at the aging temperature of 180°C. The thickness of the compound layers did
not vary much at the lower aging temperatures but followed the diffusion- controlled mechanism at 180°C. Massive Kirkendall
voids were observed in Cu3(Sn,In) layers at the aging temperature of 180°C. 相似文献
19.
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
20.
Young Min Kim Hee-Ra Roh Sungtae Kim Young-Ho Kim 《Journal of Electronic Materials》2010,39(12):2504-2512
The growth kinetics of an intermetallic compound (IMC) layer formed between Sn-3.5Ag-0.5Cu (SAC) solders and Cu-Zn alloy substrates
was investigated for samples aged at different temperatures. Scallop-shaped Cu6Sn5 formed after soldering by dipping Cu or Cu-10 wt.%Zn wires into the molten solder at 260°C. Isothermal aging was performed
at 120°C, 150°C, and 180°C for up to 2000 h. During the aging process, the morphology of Cu6Sn5 changed to a planar type in both specimens. Typical bilayer of Cu6Sn5 and Cu3Sn and numerous microvoids were formed at the SAC/Cu interfaces after aging, while Cu3Sn and microvoids were not observed at the SAC/Cu-Zn interfaces. IMC growth on the Cu substrate was controlled by volume diffusion
in all conditions. In contrast, IMC growth on Cu-Zn specimens was controlled by interfacial reaction for a short aging time
and volume diffusion kinetics for a long aging time. The growth rate of IMCs on Cu-Zn substrates was much slower due to the
larger activation energy and the lower layer growth coefficient for the growth of Cu-Sn IMCs. This effect was more prominent
at higher aging temperatures. 相似文献