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1.
In the present study, several under bump metallization (UBM) schemes using either electroplated Ni or electroless Ni (EN)
as the solderable layer are investigated. The EN and electroplated Ni are first deposited on Cu/Al2O3 substrates, followed by electroplating of thin gold coatings. Joints of 42Sn-58Bi/Au/EN/Cu/Al2O3 and 42Sn-58Bi/Au/Ni/Cu/Al2O3 are annealed at 145 C and 185CC for 30–180 minutes to investigate the interfacial reaction between the solder and metallized
substrates. For 42Sn-58Bi/Au/Ni-5.5wt.%P/Cu/Al2O3, 42Sn-58Bi/Au/Ni-12.1wt.%P/Cu/Al2O3, and 42Sn-58Bi/Au/Ni/CU/Al2O3 joints annealed at 145 C, only Ni3Sn4 intermetallic compound (IMC) formed at the solder/EN interace. When annealed at an elevated temperature of 185 C, plate-like
Ni3Sn4 IMC forms at the solder/Ni-5.5wt.%P interface, while a trace of (Ni, Cu)3Sn4 IMC is observed at the solder/Ni-12.1wt.%P interface and within the solder region. For the electroplated Ni-based multi-metallization
substrate, the Ni3Sn4 IMC is present at the solder/Ni interface during annealing at 185 C for a short period of time. In the 42Sn-58Bi/Au/EN/Cu/Al2O3 joint, the EN spalls off the EN layer and migrates into the solder region when annealed at 185 C. The interface of the solder/electroplating
Ni becomes saw-toothed as the annealing temperature is raised to 185 C. In addition, an enrichment of phosphorus is observed
at the interface of the Ni-Sn IMC and EN. 相似文献
2.
Chien-Sheng Huang Jih-Hung Yeh Bi-Lian Young Jenq-Gong Duh 《Journal of Electronic Materials》2002,31(11):1230-1237
Electroless Ni-P (EN) has been popularly adopted and used as a diffusion barrier in the under-bump metallurgy (UBM) for flip-chip
application. The EN with different P contents was first deposited on activated Cu/Al2O3 substrates. To prevent the EN from oxidation, a thin Au coating was further plated on the EN/Cu/Al2O3 substrates. Two types of solder alloys (63Sn-37Pb and 42Sn-58Bi) and two compositions of EN (Ni-5.5wt.%P and Ni-12.1wt.%P)
were employed to investigate the interfacial reaction in the joint of solder/Au/EN/Cu. Occurrence of EN and intermetallic
compound (IMC) stripping and dissolving was revealed. After annealing, Ni3Sn4 and Ni3P formed between the solder and the EN in all joints. However, some of the Ni3Sn4 IMCs stripped into the solder for a longer annealing time. The stripped EN was first observed in the Sn-Bi/Au/Ni-5.5wt.%P/Cu/Al2O3 joints annealed at 185°C for 180 min. The stripped IMCs and the EN then dissolved in the solder and formed the Ni-P-Cu-Sn-Pb
solid solution in the Sn-Pb/Au/Ni-5.5wt.%P/Cu/Al2O3 joints annealed at 200°C or 240°C. The phenomenon of IMC stripping was found in all joints. However, both the stripping and
dissolving of EN was only observed in joints with Ni-5.5wt.%P. The tendency of IMC stripping was related to the amount of
IMCs, while the EN stripping corresponded to the surface condition of the EN. 相似文献
3.
Nickel plating has been used as the under bump metallization (UBM) in the microelectronics industry. The electroplated Ni-P
UBM with different phosphorous contents (7 wt.%, 10 wt.%, and 13 wt.%) was used to evaluate the interfacial reaction between
Ni-P UBM and Sn-3Ag-0.5Cu solder paste during multiple reflow. (Cu,Ni)6Sn5 intermetallic compounds (IMC) formed in the SnAgCu solder/Ni-P UBM interface after the first reflow. For three times reflow,
(Ni,Cu)3Sn4 IMC formed, while (Cu,Ni)6Sn5 IMC spalled into the solder matrix. With further increasing cycles of reflow, the Ni-Sn-P layer formed between (Ni,Cu)3Sn4 IMC and Ni-P UBM for Ni-10wt.%P and Ni-13wt.%P UBM. However, almost no Ni-Sn-P layer was revealed for the Ni-7wt.%P UBM even
after ten cycles of reflow. In consideration of the wettability of Ni-P UBM, the interfacial reaction of SnAgCu/Ni-P, and
dissolution of Ni-P UBM, the optimal phosphorous selection in Ni-P UBM was proposed and also discussed. 相似文献
4.
Yoon Jeong-Won Kim Sang-Won Koo Ja-Myeong Kim Dae-Gon Jung Seung-Boo 《Journal of Electronic Materials》2004,33(10):1190-1199
The interfacial reactions between two Sn-Cu (Sn-0.7Cu and Sn-3Cu, wt.%) ball-grid-array (BGA) solders and the Au/Ni/Cu substrate
by solid-state isothermal aging were examined at temperatures between 70°C and 170°C for 0 to 100 days. For the Sn-0.7Cu solder,
a (Cu,Ni)6Sn5 layer was observed in the samples aged at 70–150°C. After isothermal aging at 170°C for 50 days, the solder/Ni interface
exhibited a duplex structure of (Cu,Ni)6Sn5 and (Ni,Cu)3Sn4. For the Sn-3Cu solder, only the (Cu,Ni)6Sn5 layer was formed in all aged samples. Compared to these two Sn-Cu solders, the Cu content in the (Cu,Ni)6Sn5 layer formed at the interface increased with the Cu concentration in the Sn-xCu solders. And, the shear strength was measured
to evaluate the effect of the interfacial reactions on the mechanical reliability as a function of aging conditions. The shear
strength significantly decreased after aging for 1 day and then remained nearly unchanged by further prolonged aging. In all
the samples, the fracture always occurred in the bulk solder. Also, we studied the electrical property of Cu/Sn-3Cu/Cu BGA
packages with the number of reflows. The electrical resistivity increased with the number of reflows because of an increase
of intermetallic compound (IMC) thickness. 相似文献
5.
Characteristic evaluation of electroless nickel-phosphorus deposits with different phosphorus contents 总被引:1,自引:0,他引:1
The surface morphology, electrical property and reaction with solder alloy of two electroless nickel-phosphorus (EN-P) deposits (Ni-7wt.%P and Ni-10wt.%P) were investigated in this study. The P content of the EN-P layer decreased with increasing pH value. The EN-P plating layers had an amorphous structure and the electrical resistivity of the layer increased with increasing P content. Reaction layers of Ni3Sn4, Ni2SnP and Ni3P formed at the interfaces between the Sn-3.5Ag solder and the two EN-P deposit layers. The thickness of the interfacial Ni3Sn4 intermetallic compound (IMC) layer in the Sn-3.5Ag/Ni-7wt.%P joint was thicker than that in the Sn-3.5Ag/Ni-10wt.%P joint, whereas the thickness of the Ni3P layer increased with increasing P content. These study results confirmed that the interfacial reaction between solder and the EN-P layer is significantly affected by the composition (P content) of the EN-P layer. 相似文献
6.
In flip chip technology, Al/Ni(V)/Cu under-bump metallization (UBM) is currently applicable for Pb-free solder, and Sn−Ag−Cu
solder is a promising candidate to replace the conventional Sn−Pb solder. In this study, Sn-3.0Ag-(0.5 or 1.5)Cu solder bumps
with Al/Ni(V)/Cu UBM after assembly and aging at 150°C were employed to investigate the elemental redistribution, and reaction
mechanism between solders and UBMs. During assembly, the Cu layer in the Sn-3.0Ag-0.5Cu joint was completely dissolved into
solders, while Ni(V) layer was dissolved and reacted with solders to form (Cu1−y,Niy)6Sn5 intermetallic compound (IMC). The (Cu1−y,Niy)6Sn5 IMC gradually grew with the rate constant of 4.63 × 10−8 cm/sec0.5 before 500 h aging had passed. After 500 h aging, the (Cu1−y,Niy)6Sn5 IMC dissolved with aging time. In contrast, for the Sn-3.0Ag-1.5Cu joint, only fractions of Cu layer were dissolved during
assembly, and the remaining Cu layer reacted with solders to form Cu6Sn5 IMC. It was revealed that Ni in the Ni(V) layer was incorporated into the Cu6Sn5 IMC through slow solid-state diffusion, with most of the Ni(V) layer preserved. During the period of 2,000 h aging, the growth
rate constant of (Cu1−y,Niy)6Sn5 IMC was down to 1.74 × 10−8 cm/sec0.5 in, the Sn-3.0Ag-1.5Cu joints. On the basis of metallurgical interaction, IMC morphology evolution, growth behavior of IMC,
and Sn−Ag−Cu ternary isotherm, the interfacial reaction mechanism between Sn-3.0Ag-(0.5 or 1.5)Cu solder bump and Al/Ni(V)/Cu
UBM was discussed and proposed. 相似文献
7.
Guh-Yaw Jang Jeng-Gong Duh Hideyuki Takahashi Szu-Wei Lu Jen-Chuan Chen 《Journal of Electronic Materials》2006,35(9):1745-1754
Sn-Ag-Cu solder is a promising candidate to replace conventional Sn-Pb solder. Interfacial reactions for the flip-chip Sn-3.0Ag-(0.5
or 1.5)Cu solder joints were investigated after aging at 150°C. The under bump metallization (UBM) for the Sn-3.0Ag-(0.5 or
1.5)Cu solders on the chip side was an Al/Ni(V)/Cu thin film, while the bond pad for the Sn-3.0Ag-0.5Cu solder on the plastic
substrate side was Cu/electroless Ni/immersion Au. In the Sn-3.0Ag-0.5Cu joint, the Cu layer at the chip side dissolved completely
into the solder, and the Ni(V) layer dissolved and reacted with the solder to form a (Cu1−y,Niy)6Sn5 intermetallic compound (IMC). For the Sn-3.0Ag-1.5Cu joint, only a portion of the Cu layer dissolved, and the remaining Cu
layer reacted with solder to form Cu6Sn5 IMC. The Ni in Ni(V) layer was incorporated into the Cu6Sn5 IMC through slow solid-state diffusion, with most of the Ni(V) layer preserved. At the plastic substrate side, three interfacial
products, (Cu1−y,Niy)6Sn5, (Ni1−x,Cux)3Sn4, and a P-rich layer, were observed between the solder and the EN layer in both Sn-Ag-Cu joints. The interfacial reaction
near the chip side could be related to the Cu concentration in the solder joint. In addition, evolution of the diffusion path
near the chip side in Sn-Ag-Cu joints during aging is also discussed herein. 相似文献
8.
G. Ghosh 《Journal of Electronic Materials》2004,33(3):229-240
The reactive interdiffusion between a Sn-3.0wt.%Ag-0.7wt.%Cu solder and thin-film Ti/Ni/Ag metallizations on two semiconductor
devices, a diode and a metal-oxide-semiconductor field-effect transistor (MOSFET), and a Au-layer on the substrates are studied.
Comprehensive microanalytical techniques, scanning electron microscopy, transmission electron microscopy (TEM), and analytical
electron microscopy (AEM) are employed to identify the interdiffusion processes during fabrication and service of the devices.
During the reflow process of both diode and MOSFET devices, (1) the Ag layer dissolves in the liquid solder; (2) two intermetallics,
(Ni,Cu)3Sn4 and (Cu,Ni)6Sn5, form near the back metal/solder interface; and (3) the Au metallization in the substrate side dissolves in the liquid solder,
resulting in precipitation of the (Au,Ni,Cu)Sn4 intermetallic during solidification. During solid-state aging of both diode and MOSFET solder joints at 125°C and 200°C,
the following atomic transport processes occur: (1) interdiffusion of Cu, Ni, and Sn, leading to the growth of a (Ni,Cu)3Sn4 layer until the Ni layer is completely consumed; (2) interdiffusion of Au, Cu, Ni, and Sn through the (Ni,Cu)3Sn4 layer and unconsumed Ni layer to the Ti layer to form a solid solution; and (3) further interdiffusion of Au, Cu, Ni, and
Sn through the (Ni,Cu)3Sn4 layer to from an (Au,Ti,Ni,Cu)Sn4 layer. The growth of the latter layer continues until the entire Ti layer is consumed. 相似文献
9.
(Cu,Ni)6Sn5 is an important intermetallic compound (IMC) in lead-free Sn-Ag-Cu solder joints on Ni substrate. The formation, growth, and microstructural evolution of (Cu,Ni)6Sn5 are closely correlated with the concentrations of Cu and Ni in the solder. This study reports the interfacial behaviors of (Cu,Ni)6Sn5 IMC (Sn-31 at.%Cu-24 at.%Ni) with various Sn-Cu, Sn-Ni, and Sn-Cu-Ni solders at 250°C. The (Cu,Ni)6Sn5 substrate remained intact for Sn-0.7 wt.%Cu solder. When the Cu concentration was decreased to 0.3 wt.%, (Cu,Ni)6Sn5 significantly dissolved into the molten solder. Moreover, (Cu,Ni)6Sn5 dissolution and (Ni,Cu)3Sn4 formation occurred simultaneously for the Sn-0.1 wt.%Ni solder. In Sn-0.5 wt.%Cu-0.2 wt.%Ni solder, many tiny (Cu,Ni)6Sn5 particulates were formed and dispersed in the solder matrix, while in Sn-0.3 wt.%Cu-0.2 wt.%Ni a lot of (Ni,Cu)3Sn4 grains were produced. Based on the local equilibrium hypothesis, these results are further discussed based on the liquid–(Cu, Ni)6Sn5–(Ni,Cu)3Sn4 tie-triangle, and the liquid apex is suggested to be very close to Sn-0.4 wt.%Cu-0.2 wt.%Ni. 相似文献
10.
Eutectic solder balls (63Sn-37Pb) joined to Cu pads with an Au/Ni metallization have been widely used in wafer-level chip-size
package (WLCSP) technology for providing electrical and mechanical interconnections between components. However, some reliability
issues must be addressed regarding the intermetallic compounds (IMCs). The formation of a brittle IMC layer between the solder/Cu
pad interface impacts considerably upon the solder-ball shear strength. In addition, it will degrade the long-term operating
reliability of the WLCSP. This study investigates, by means of experiments, the growth of the IMC layer under isothermal aging
for the eutectic Sn-Pb solder reflowed on a Cu pad with an Au/Ni metallization. Forming the Cu pad with an Au/Ni metallization
was achieved by a simple semiconductor-manufacturing process. The effects of the intermetallic layer on solder-ball shear
strength were examined for various parameters, including the thickness of the Au layer, solder-ball size, and the diameter
of the Cu pad. Experimental results indicate that two IMC layers, Au0.5Ni0.5Sn4 and Ni3Sn4, form at the solder/Cu pad interface after aging. The Au0.5Ni0.5Sn4 intermetallic layer dominates the total thickness of the IMC layer and grows with aging time while the solder-ball shear
strength decreases after aging. The degradation of the solder-ball shear strength was found to be caused mainly by the formation
of the Au0.5Ni0.5Sn4 layer. The experimental results established that a thinner Au layer on Cu pad can effectively control the degradation of
solder-ball shear strength, and this is especially true for smaller ball sizes. 相似文献
11.
Moon Gi Cho Sung K. Kang Sun-Kyoung Seo Da-Yuan Shih Hyuck Mo Lee 《Journal of Electronic Materials》2009,38(11):2242-2250
The effects of the addition of Zn to Sn-0.7Cu solders are investigated. The study is focused on the interfacial reactions,
microstructures, and mechanical properties after reaction with Ni-P under bump metallurgies (UBMs). The Zn contents in Sn-0.7Cu-xZn are varied as 0.2, 0.4, and 0.8 (in wt.% unless otherwise specified). In the reaction with Ni-P UBM during thermal aging
at 150°C for 1000 h, (Cu,Ni)6Sn5 intermetallic compounds (IMCs) are formed at the Sn-0.7Cu/UBM interface, whereas Zn is incorporated into IMCs to form (Cu,Ni,Zn)6Sn5 in the Zn-doped solders. As the Zn content increases, the interfacial IMC thickness is reduced. A total reduction of about
40% in IMC thickness was observed for the 0.8% Zn-doped Sn-Cu. The same IMC particles are also observed in the matrix of each
solder. In Sn-0.7Cu, (Cu,Ni)6Sn5 particles are coarsened during aging, while (Cu,Ni,Zn)6Sn5 particles in the Zn-added solders are less coarsened and remain much smaller than (Cu,Ni)6Sn5. The growth rate of (Cu,Ni)6Sn5 during thermal aging is significantly suppressed by the addition of Zn. Consequently, after reaction with Ni-P UBM, the Zn-doped
solders exhibit a thermally stable microstructure as measured by hardness and shear strength. 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.
The eutectic Sn-Ag solder alloy is one of the candidates for the Pb-free solder, and Sn-Pb solder alloys are still widely
used in today’s electronic packages. In this tudy, the interfacial reaction in the eutectic Sn-Ag and Sn-Pb solder joints
was investigated with an assembly of a solder/Ni/Cu/Ti/Si3N4/Si multilayer structures. In the Sn-3.5Ag solder joints reflowed at 260°C, only the (Ni1−x,Cux)3Sn4 intermetallic compound (IMC) formed at the solder/Ni interface. For the Sn-37Pb solder reflowed at 225°C for one to ten cycles,
only the (Ni1−x,Cux)3Sn4 IMC formed between the solder and the Ni/Cu under-bump metallization (UBM). Nevertheless, the (Cu1−y,Niy)6Sn5 IMC was observed in joints reflowed at 245°C after five cycles and at 265°C after three cycles. With the aid of microstructure
evolution, quantitative analysis, and elemental distribution between the solder and Ni/Cu UBM, it was revealed that Cu content
in the solder near the solder/IMC interface played an important role in the formation of the (Cu1−y,Niy)6Sn5 IMC. In addition, the diffusion behavior of Cu in eutectic Sn-Ag and Sn-Pb solders with the Ni/Cu UBM were probed and discussed.
The atomic flux of Cu diffused through Ni was evaluated by detailed quantitative analysis in an electron probe microanalyzer
(EPMA). During reflow, the atomic flux of Cu was on the order of 1016−1017 atoms/cm2sec in both the eutectic Sn-Ag and Sn-Pb systems. 相似文献
14.
Effects of Ce Addition on the Microstructure and Mechanical Properties of Sn-58Bi Solder Joints 总被引:1,自引:0,他引:1
The effects of a rare-earth element on the microstructure, mechanical properties, and whisker growth of Sn-58Bi alloys and
solder joints in ball grid array (BGA) packages with Ag/Cu pads have been investigated. Mechanical testing indicated that
the elongation of Sn-58Bi alloys doped with Ce increased significantly, and the tensile strength decreased slightly, in compar- ison
with undoped Sn-58Bi. In addition, the growth of both fiber- and hillock-shaped tin whiskers on the surface of Sn-58Bi-0.5Ce
was retarded in the case of Sn-3Ag-0.5Cu-0.5Ce alloys. The growth of interfacial intermetallic compounds (IMC) in Sn-58Bi-0.5Ce
solder joints was slower than that in Sn-58Bi because the activity of Ce atoms at the interface of the Cu6Sn5 IMC/solder was reduced. The reflowed Sn-58Bi and Sn-58Bi-0.5Ce BGA packages with Ag/Cu pads had a ball shear strength of
7.91 N and 7.64 N, which decreased to about 7.13 N and 6.87 N after aging at 100°C for 1000 h, respectively. The reflowed
and aged solder joints fractured across the solder balls with ductile characteristics after ball shear tests. 相似文献
15.
Moon Gi Cho Kyung Wook Paik Hyuck Mo Lee Seong Woon Booh Tae-Gyu Kim 《Journal of Electronic Materials》2006,35(1):35-40
The interfacial reaction between 42Sn-58Bi solder (in wt.% unless specified otherwise) and electroless Ni-P/immersion Au was
investigated before and after thermal aging, with a focus on the formation and growth of an intermetallic compound layer,
consumption of under bump metallurgy (UBM), and bump shear strength. The immersion Au layer with thicknesses of 0 μm (bare
Ni), 0.1 μm, and 1 μm was plated on a 5-μm-thick layer of electroless Ni-P (with 14–15 at.% P). The 42Sn-58Bi solder balls
were then fabricated on three different UBM structures by using screen printing and pre-reflow. A Ni3Sn4 layer formed at the joint interface after the pre-reflow for all three UBM structures. On aging at 125°C, a quaternary phase,
identified as Sn77Ni15Bi6Au2, was observed above the Ni3Sn4 layer in the UBM structures that contain Au. The thick Sn77Ni15Bi6Au2 layer degraded the integrity of the solder joint, and the shear strength of the solder bump was about 40% less than the nonaged
joints. 相似文献
16.
Yee-Wen Yen Wei-Kai Liou Hong-Yao Wei Chiapyng Lee 《Journal of Electronic Materials》2009,38(1):93-99
This study investigates the interfacial reactions between Sn-3.0wt.% Ag-0.5wt.%Cu (SAC) and Sn-0.7wt.%Cu (SC) on In/Ni/Cu
multilayer substrates using the solid–liquid interdiffusion bonding technique. Samples were reflowed first at 160°C, 180°C,
and 200°C for various periods, and then aged at 100°C for 100 h to 500 h. The scalloped Cu6Sn5 phase was formed at the SAC/In/Ni/Cu and SC/In/Ni/Cu interfaces. When the reflowing temperatures were 160°C and 180°C, a
ternary Ni-In-Sn intermetallic compound (IMC) was formed when the samples were further aged at 100°C. This ternary Ni-In-Sn
IMC could be the binary Ni3Sn4 phase with extensive Cu and In solubilities, or the ternary Sn-In-Ni compound with Cu solubility, or even a quaternary compound.
As the reflow temperature was increased to 200°C, only one Cu6Sn5 phase was formed at the solder/substrate interface with the heat treatment at 100°C for 500 h. Mechanical test results indicated
that the formation of the Ni-In-Sn ternary IMC weakened the mechanical strength of the solder joints. Furthermore, the solid–liquid
interdiffusion (SLID) technique in this work effectively reduced the reflow temperature. 相似文献
17.
During the reflow process of Sn-3.5Ag solder ball grid array (BGA) packages with Ag/Cu and Au/Ni/Cu pads, Ag and Au thin films
dissolve rapidly into the liquid solder, and the Cu and Ni layers react with the Sn-3.5Ag solder to form Cu6Sn5 and Ni3Sn4 intermetallic compounds at the solder/pad interfaces, respectively. The Cu6Sn5 intermetallic compounds also appear as clusters in the solder matrix of Ag surface-finished packages accompanied by Ag3Sn dispersions. In the solder matrix of Au/Ni surface-finished specimens, Ag3Sn and AuSn4 intermetallics can be observed, and their coarsening coincides progressively with the aging process. The interfacial Cu6Sn5 and Ni3Sn4 intermetallic layers grow by a diffusion-controlled mechanism after aging at 100 and 150°C. Ball shear strengths of the reflowed
Sn-3.5Ag packages with both surface finishes are similar, displaying the same degradation tendencies as a result of the aging
effect. 相似文献
18.
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
19.
Influence of interfacial reaction layer on reliability of chip-scale package joint from using Sn-37Pb and Sn-8Zn-3Bi solder 总被引:1,自引:0,他引:1
Chung-Hee Yu Kyung-Seob Kim Hyung-Il Kim Hyo-Joeng Jeon 《Journal of Electronic Materials》2005,34(2):161-167
The microstructure of Sn-37Pb and Sn-8Zn-3Bi solders and the full strength of these solders with an Au/Ni/Cu pad under isothermal
aging conditions were investigated. The full strengths tended to decrease as the aging temperature and time increased, regardless
of the properties of the solders. The Sn-8Zn-3Bi had higher full strength than Sn-37Pb. In the Sn-37Pb solder, Ni3Sn4 compounds and irregular-shaped Pb-rich phase were embedded in a β-Sn matrix. The Ni3Sn4 compounds were observed at the interface between the solder and pad. The microstructure of the as-reflowed Sn-8Zn-3Bi solder
mainly consists of the β-Sn matrix scattered with Zn-rich phase. Zinc first reacted with Au and then was transformed to the
AuZn compound. With aging, Ni5Zn21 compounds were formed at the Ni layer. Finally, a Ni5Zn21 phase, divided into three layers, was formed with column-shaped grains, and the thicknesses of the layers were changed. 相似文献
20.
H. R. Kotadia O. Mokhtari M. Bottrill M. P. Clode M. A. Green S. H. Mannan 《Journal of Electronic Materials》2010,39(12):2720-2731
In this study we consider the effect of separately adding 0.5 wt.% to 1.5 wt.% Zn or 0.5 wt.% to 2 wt.% Al to the eutectic
Sn-3.5Ag lead-free solder alloy to limit intermetallic compound (IMC) growth between a limited volume of solder and the contact
metallization. The resultant solder joint microstructure after reflow and high-temperature storage at 150°C for up to 1000 h
was investigated. Experimental results confirmed that the addition of 1.0 wt.% to 1.5 wt.% Zn leads to the formation of Cu-Zn
on the Cu substrate, followed by massive spalling of the Cu-Zn IMC from the Cu substrate. Growth of the Cu6Sn5 IMC layer is significantly suppressed. The addition of 0.5 wt.% Zn does not result in the formation of a Cu-Zn layer. On
Ni substrates, the Zn segregates to the Ni3Sn4 IMC layer and suppresses its growth. The addition of Al to Sn-3.5Ag solder results in the formation of Al-Cu IMC particles
in the solder matrix when reflowed on the Cu substrate, while on Ni substrates Al-Ni IMCs spall into the solder matrix. The
formation of a continuous barrier layer in the presence of Al and Zn, as reported when using solder baths, is not observed
because of the limited solder volumes used, which are more typical of reflow soldering. 相似文献