共查询到20条相似文献,搜索用时 78 毫秒
1.
M. J. Rizvi Y. C. Chan C. Bailey H. Lu M. N. Islam B. Y. Wu 《Journal of Electronic Materials》2005,34(8):1115-1122
The wettability of newly developed Sn-2.8Ag-0.5Cu-1.0Bi lead-free solder on Cu and Ni substrates was assessed through the
wetting balance tests. The wettability assessment parameters such as contact angle (ϑc) and maximum wetting force (Fw) were documented for three solder bath temperatures with three commercial fluxes, namely, no-clean (NC), nonactivated (R),
and water-soluble organic acid flux (WS). It was found that the lead-free Sn-2.8Ag-0.5Cu-1.0Bi solder exhibited less wetting
force, i.e., poorer wettability, than the conventional Sn-37Pb solder for all flux types and solder bath temperatures. The
wettability of Sn-2.8Ag-0.5Cu-1.0Bi lead-free solder on Cu substrate was much higher than that on Ni substrate. Nonwetting
for Sn-2.8Ag-0.5Cu-1.0Bi and Sn-Pb solders on Ni substrate occurred when R-type flux was used. A model was built and simulations
were performed for the wetting balance test. The simulation results were found very close to the experimental results. It
was also observed that larger values of immersion depth resulted in a decrease of the wetting force and corresponding meniscus
height, whereas the increase in substrate perimeter enhanced the wettability. The wetting reactions between the solder and
Cu/Ni substrates were also investigated, and it was found that Cu atoms diffused into the solder through the intermetallic
compounds (IMCs) much faster than did the Ni atoms. Rapid formation of IMCs inhibited the wettability of Sn-2.8Ag-0.5Cu-1.0Bi
solder compared to the Sn-Pb solder. 相似文献
2.
Fatigue crack-growth behavior and mechanical properties of Sn-3Ag-0.5Cu, Sn-3Ag-0.5Cu-1Bi, and Sn-3Ag-0.5Cu-3Bi solders have
been investigated at room temperature (20°C). The tensile strength and hardness of the solders increased with increasing Bi
content. However, the yield strengths of Sn-3Ag-0.5Cu-1Bi and Sn-3Ag-0.5Cu-3Bi solders were nearly similar, but the 3Bi solder
exhibited the lowest ductility. Fatigue crack-growth behavior of the solders was dominantly cycle dependent in the range of
stress ratios from 0.1–0.7 at a frequency of 10 Hz, except for the Sn-3Ag-0.5Cu solder tested at a stress ratio of 0.7. Mixed
intergranular/transgranular crack propagation was observed for the Sn-3Ag-0.5Cu solder tested at the stress ratio of 0.7,
indicating the importance of creep in crack growth. The Sn-3Ag-0.5Cu-1Bi and Sn-3Ag-0.5Cu-3Bi solders had higher resistance
to time-dependent crack growth, resulting from the strengthening effect of the Bi constituent. It appears that the addition
of Bi above a certain concentration is harmful to the mechanical properties of Sn-3Ag-0.5Cu. 相似文献
3.
Solder alloys doped with rare-earth elements have been reported to show many beneficial effects. However, tin whiskers have
been observed to appear on the surface of Sn-3Ag-0.5Cu-0.5Ce solder joints after air exposure for short periods. Such a phenomenon
of abnormal whisker growth may significantly degrade the reliability of electronic packaging. The present study shows that
the tin whiskers can be prevented by the addition of 0.5 wt.% Zn into a Sn-3Ag-0.5Cu-0.5Ce solder. The inhibition effect on
the whisker growth is correlated to the refining of (Ce0.9Zn0.1)Sn3 intermetallics in this Sn-3Ag-0.5Cu-0.5Ce-0.5Zn alloy. 相似文献
4.
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
5.
Yun-Hwan Jo Joo Won Lee Sun-Kyoung Seo Hyuck Mo Lee Hun Han Dong Chun Lee 《Journal of Electronic Materials》2008,37(1):110-117
A combination solder of Sn-3.0Ag-0.5Cu (numbers are all in weight percent unless specified otherwise) wrapped by Sn-57Bi-1Ag
was tested for application to three-dimensional (3-D) multistack packaging. The experimental variables controlled were the
reflow peak temperatures (170, 185, 200, and 230°C), the reflow cycles (up to four times), and the mask which controls the
amount of Sn-57Bi-1Ag solder paste (two sizes). We demonstrate and evaluate the combination solder structure, focusing on
microstructural changes and the shear strength. The degree of mixing in the combination solder, which is enhanced by an increase
in the reflow peak temperature, is independent of the number of reflow cycles. The ball shear strength and the lab shear strength
both increased with increases in the reflow peak temperatures. This behavior is explained by the amount of the brittle Bi
phase that constitutes the eutectic Sn-Bi phase. 相似文献
6.
Low-cycle fatigue (LCF) behavior of a lead-free Sn-3.5Ag-0.5Cu solder alloy was investigated at various combinations of strain
ratio (R = −1, 0, and 0.5) and tensile hold time (0, 10, and 100 sec). Results showed that the LCF life of the given solder,
at each given combination of testing conditions, could be individually described by a Coffin-Manson relationship. An increase
of strain ratio from R=−1 to 0 and to 0.5 would cause a significant reduction of LCF life due to a mean strain effect instead
of mean stress effect. LCF life was also markedly reduced when the hold time at tensile peak strain was increased from 0 to
100 sec, as a result of additional creep damage generated during LCF loading. With consideration of the effects of strain
ratio and tensile hold time, a unified LCF lifetime model was proposed and did an excellent job in describing the LCF lives
for all given testing conditions. 相似文献
7.
8.
F. Guo J. Lee J. P. Lucas K. N. Subramanian T. R. Bieler 《Journal of Electronic Materials》2001,30(9):1222-1227
The creep deformation behavior of eutectic Sn-3.5Ag based Ni particle rein forced composite solder joints was investigated.
The Ni particle reinforced composite solder was prepared by mechanically dispersing 15 vol.% of Ni particles into eutectic
Sn-3.5Ag solder paste. Static-loading creep tests were carried out on solder joint specimens at 25 C, 65 C, and 105 C, representing
homologous temperatures ranging from 0.6 to 0.78. A novel-design, miniature creep-testing frame was utilized in this study.
Various creep parameters such as the global and localized creep strain, steady-state creep rate, onset of tertiary creep and
the activation energy for creep were quantified by mapping the distorted laser ablation pattern imprinted on the solder joint
prior to testing. The Ni-reinforced composite solder joint showed improved creep resistance compared to the results previously
reported for eutectic Sn-3.5Ag solder, Sn-4.0Ag-0.5Cu solder alloys, and for eutectic Sn-3.5Ag solder reinforced with Cu or
Ag particle reinforcements. The activation energy for creep was ∼0.52 eV for Sn-3.5Ag and Sn-4Ag-0.5Cu solder alloys. The
activation energies ranged from 0.55–0.64 eV for Cu, Ag, and Ni reinforced composite solder joints, respectively. Most often,
creep fracture occurred closer to one side of the solder joint within the solder matrix. 相似文献
9.
Three kinds of Sn-Ag-based lead-free solders, Sn-3.5Ag-0.7Cu, Sn-3.5Ag-0.5Cu-0.07Ni-0.01Ge, and Sn-3.5Ag-0.07Ni (in wt.%),
were selected to explore the effect of microelements (Ni and Ge) on the interfacial reaction between the solder and the Cu
substrate. The thickness of the interfacial intermetallics formed with the Sn-3.5Ag-0.5Cu-0.07Ni-0.01Ge and Sn-3.5Ag-0.07Ni
solders is several times that of the Sn-3.5Ag-0.7Cu solder. The added microelements converted the feature of interfacial intermetallics
from pebble shape to worm shape. However, the results of x-ray diffraction (XRD) analysis suggest that the interfacial intermetallics
formed with both solders have the same crystal structure. The results of energy dispersive spectroscopy (EDS) analysis show
that the major interfacial intermetallic formed with the Sn-3.5Ag-0.7Cu solder is Cu6Sn5, while it is (Cux,Ni1−x)6Sn5 with Sn-3.5Ag-0.5Cu-0.07Ni-0.01Ge. Ni influences the interfacial intermetallics and plays the influential role on the difference
of interfacial reaction rate between liquid solder and solid Cu and the morphology of interfacial intermetallics. Additionally,
the growth kinetics of the interfacial intermetallic compounds (IMCs) formed in the systems of Cu/Sn-3.5Ag-0.7Cu and Cu/Sn-3.5Ag-0.07Ni
at high-temperature storage was also explored. 相似文献
10.
11.
B. A. Cook I. E. Anderson J. L. Harringa S. K. Kang 《Journal of Electronic Materials》2003,32(12):1384-1391
Solder joints were prepared from seven eutectic and near-eutectic Sn-based compositions and characterized for electrical resistivity
after 100 h and 1,000 h of isothermal aging at 423 K. The solder joint samples were prepared by hand soldering to copper substrates,
and the post-heat treatment resistivity was measured at room temperature in a specially designed, four-point probe fixture.
Compositions tested included Sn-3.5Ag, Sn-3.7Ag-0.9Cu, Sn-3.0Ag-0.5Cu, Sn-3.6Ag-1.0Cu, and Sn-3.9Ag-0.6Cu. In addition, the
effect of a minor addition of a fourth element, designed to improve high-temperature shear strength, was also evaluated in
the compositions Sn-3.7Ag-0.6Cu-0.3Co and Sn-3.7Ag-0.7Cu-0.2Fe. The observed changes in electrical resistivity are discussed
in terms of microstructural coarsening, diffusional transport from the substrate, and nucleation of precipitate phases. 相似文献
12.
Jong-Woong Kim Dae-Gon Kim Won Sik Hong Seung-Boo Jung 《Journal of Electronic Materials》2005,34(12):1550-1557
The microstructural investigation and thermomechanical reliability evaluation of the Sn-3.0Ag-0.5Cu solder bumped flip-chip
package were carried out during the thermal shock test of the package. In the initial reaction, the reaction product between
the solder and Cu mini bump of chip side was Cu6Sn5 intermetallic compound (IMC) layer, while the two phases which were (Cu,Ni)6Sn5 and (Ni,Cu)3Sn4 were formed between the solder and electroless Ni-P layer of the package side. The cracks occurred at the corner solder joints
after the thermal shocks of 400 cycles. The primary failure mechanism of the solder joints in this type of package was confirmed
to be thermally-activated solder fatigue failure. The premature brittle interfacial failure sometimes occurred in the package
side, but nearly all of the failed packages showed the occurrence of the typical fatigue cracks. The finite-element analyses
were conducted to interpret the failure mechanisms of the packages, and revealed that the cracks were induced by the accumulation
of the plastic work and viscoplastic shear strains. 相似文献
13.
Nanoparticles of the Lead-free Solder Alloy Sn-3.0Ag-0.5Cu with Large Melting Temperature Depression
Chang Dong Zou Yu Lai Gao Bin Yang Xin Zhi Xia Qi Jie Zhai Cristina Andersson Johan Liu 《Journal of Electronic Materials》2009,38(2):351-355
Due to the toxicity of lead (Pb), Pb-containing solder alloys are being phased out from the electronics industry. This has
lead to the development and implementation of lead-free solders. Being an environmentally compatible material, the lead-free
Sn-3.0Ag-0.5Cu (wt.%) solder alloy is considered to be one of the most promising alternatives to replace the traditionally
used Sn-Pb solders. This alloy composition possesses, however, some weaknesses, mainly as a result of its higher melting temperature
compared with the Sn-Pb solders. A possible way to decrease the melting temperature of a solder alloy is to decrease the alloy
particle size down to the nanometer range. The melting temperature of Sn-3.0Ag-0.5Cu lead-free solder alloy, both as bulk
and nanoparticles, was investigated. The nanoparticles were manufactured using the self-developed consumable-electrode direct
current arc (CDCA) technique. The melting temperature of the nanoparticles, with an average size of 30 nm, was found to be
213.9°C, which is approximately 10°C lower than that of the bulk alloy. The developed CDCA technique is therefore a promising
method to manufacture nanometer-sized solder alloy particles with lower melting temperature compared with the bulk alloy. 相似文献
14.
Tung-Han Chuang Chih-Yuan Cheng Tao-Chih Chang 《Journal of Electronic Materials》2009,38(12):2762-2769
Sn-Ag-Cu solders doped with rare-earth elements were reported to exhibit beneficial mechanical properties; however, rapid
whisker growth could be induced. In order to retain the advantageous effects of rare-earth doping without causing the formation
of tin whiskers, a Sn-3Ag-0.5Cu-0.05Ce alloy was suggested. In the present study, metallographic observations indicate that
whisker growth is indeed prevented in this alloy. However, tensile tests with the bulk materials show that the ultimate tensile
strength and Young’s modulus of this Sn-3Ag-0.5Cu-0.05Ce alloy are only slightly higher than those of undoped Sn-3Ag-0.5Cu.
Further reliability tests with actual ball grid array packages indicate that the Sn-3Ag-0.5Cu-0.05Ce solder joints have fatigue
lives similar to those of undoped Sn-3Ag-0.5Cu specimens regardless of the various surface finishes, such as electroless nickel/immersion
gold (ENIG), immersion tin (ImSn), and organic solderability preservatives (OSP). The results suggest that, although lowering
the content of rare-earth elements in solders can inhibit the occurrence of rapid whisker growth, it cannot ensure the improvement
of the tensile properties of bulk solders and the fatigue reliability of solder joints in actual packages. 相似文献
15.
G. Ghosh 《Journal of Electronic Materials》2004,33(10):1080-1091
The interfacial reaction between two prototype multicomponent lead-free solders, Sn-3.4Ag-1Bi-0.7Cu-4In and Sn-3.4Ag-3Bi-0.7Cu-4In
(mass%), and Ag, Cu, Ni, and Pd substrates are studied at 250°C and 150°C. The microstructural characterization of the solder
bumps is carried out by scanning electron microscopy (SEM) coupled with energy dispersive x-ray analysis. Ambient temperature,
isotropic elastic properties (bulk, shear, and Young’s moduli and Poisson’s ratio) of these solders along with eutectic Sn-Ag,
Sn-Bi, and Sn-Zn solders are measured. The isotropic elastic moduli of multicomponent solders are very similar to the eutectic
Sn-Ag solder. The measured solubility of the base metal in liquid solders at 250°C agrees very well with the solubility limits
reported in assessed Sn-X (X=Ag, Cu, Ni, Pd) phase diagrams. The measured contact angles were generally less than 15° on Cu
and Pd substrates, while they were between 25° and 30° on Ag and Ni substrates. The observed intermediate phases in Ag/solder
couples were Ag3Sn after reflow at 250°C and Ag3Sn and ζ (Ag-Sn) after solid-state aging at 150°C. In Cu/solder and Ni/solder couples, the interfacial phases were Cu6Sn5 and (Cu,Ni)6Sn5, respectively. In Pd/solder couples, only PdSn4 after 60-sec reflow, while both PdSn4 and PdSn3 after 300-sec reflow, were observed. 相似文献
16.
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
17.
S. Terashima T. Kohno A. Mizusawa K. Arai O. Okada T. Wakabayashi M. Tanaka K. Tatsumi 《Journal of Electronic Materials》2009,38(1):33-38
Thermal fatigue properties of commercial LF35 (Sn-1.2Ag-0.5Cu-0.05Ni), SAC105 (Sn-1Ag-0.5Cu), and SAC305 (Sn-3Ag-0.5Cu) solders
on Casio’s wafer-level packages are discussed from the viewpoints of both morphology and grain boundary character. Orientation
imaging microscopy revealed that both LF35 and SAC305 resisted the coarsening of tin grains during thermal fatigue as compared
with SAC105, correlating with their greater fraction of coincidence site lattice boundaries. This seems to explain why LF35
has superior thermal fatigue life in spite of its lower silver content. 相似文献
18.
Although it has been verified that tin whiskers can be prevented by the addition of 0.5 wt.% Zn into a Sn-3Ag-0.5Cu-0.5Ce solder, no detailed studies have been conducted on interfacial reactions and mechanical properties of Sn-3Ag-0.5Cu-0.5Ce-xZn solder joints with an immersion Ag surface finish. The intermetallic compounds formed during the reflow and aging of Sn-3Ag-0.5Cu and Sn-3Ag-0.5Cu-0.5Ce-xZn solder ball grid array (BGA) packages were investigated. Because more heterogeneous nucleation sites, provided by CeSn3 intermetallics and Zn atoms, formed in the Sn-3Ag-0.5Cu-0.5Ce-xZn solder matrix, and Cu and Zn have a stronger affinity than Cu and Sn, the Cu-Sn intermetallics growth in Sn-3Ag-0.5Cu-0.5Ce-xZn solder joints with Ag/Cu pads was suppressed. The 0.2% Zn addition for inhibiting rapid whisker growth in RE-doped Sn-Ag-Cu solder joints is more appropriate than 0.5 wt.% additions, as excess Zn addition causes poor oxidation resistance and inferior bonding strength. 相似文献
19.
E.H. Wong C.S. Selvanayagam S.K.W. Seah W.D. van Driel J.F.J.M. Caers X.J. Zhao N. Owens L.C. Tan D.R. Frear M. Leoni Y.-S. Lai C.-L. Yeh 《Journal of Electronic Materials》2008,37(6):829-836
The stress–strain properties of eutectic Sn-Pb and lead-free solders at strain rates between 0.1 s−1 and 300 s−1 are required to support finite-element modeling of the solder joints during board-level mechanical shock and product-level
drop-impact testing. However, there is very limited data in this range because this is beyond the limit of conventional mechanical
testing and below the limit of the split Hopkinson pressure bar test method. In this paper, a specialized drop-weight test
was developed and, together with a conventional mechanical tester, the true stress–strain properties of four solder alloys
(63Sn-37Pb, Sn-1.0Ag-0.1Cu, Sn-3.5Ag, and Sn-3.0Ag-0.5Cu) were generated for strain rates in the range from 0.005 s−1 to 300 s−1. The sensitivity of the solders was found to be independent of strain level but to increase with increased strain rate. The
Sn-3.5Ag and the Sn-3.0Ag-0.5Cu solders exhibited not only higher flow stress at relatively low strain rate but, compared
to Sn-37Pb, both also exhibited higher rate sensitivity that contributes to the weakness of these two lead-free solder joints
when subjected to drop impact loading. 相似文献
20.
Dissolution behavior of Cu and Ag substrates in molten solders 总被引:1,自引:0,他引:1
This study investigated the dissolution behavior of Cu and Ag substrates in molten Sn, Sn-3.5Ag, Sn-4.0Ag-0.5Cu, Sn-8.6Zn
and Sn-8.55Zn-0.5Ag-0.1Al-0.5Ga lead-free solders as well as in Sn-37Pb solder for comparison at 300, 350, and 400°C. Results
show that Sn-Zn alloys have a substantially lower dissolution rate of both Cu and Ag substrates than the other solders. Differences
in interfacial intermetallic compounds formed during reaction and the morphology of these compounds strongly affected the
substrate dissolution behavior. Soldering temperature and the corresponding solubility limit of the substrate elements in
the liquid solder also played important roles in the interfacial morphology and dissolution rate of substrate. 相似文献