共查询到20条相似文献,搜索用时 31 毫秒
1.
M. L. Huang C. M. L. Wu J. K. L. Lai Y. C. Chan 《Journal of Electronic Materials》2000,29(8):1021-1026
In a previous study, a lead-free solder, Sn-6Bi-2Ag-0.5Cu, was developed by mechanical alloying. The alloy shows great potential
as a lead-free solder system. In the present work, the microstructural evolution during thermal shock and aging was examined.
In the as-soldered joints small bismuth (1 μm to 2 μm) and Ag3Sn (1 μm) particles were finely dispersed in a nearly pure tin matrix with a small amount of η-Cu6Sn5 phase in the bulk of solder. During thermal shock and aging microstructural evolution occurred with Cu-Sn intermetallic compound
(IMC) layer growth at interface, bismuth phase coarsening and Ag3Sn phase coarsening. The microstructure of the solder appeared to be stable at high temperature. The shear strength of the
present solder joint is higher than that of Sn-37Pb and Sn-3.5Ag solders. Shear failure occurred Cu-Sn IMC layer-solder interface
and in the bulk of solder. 相似文献
2.
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
3.
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
4.
Chiang-Ming Chuang Hui-Tzu Hung Pei-Chi Liu Kwang-Lung Lin 《Journal of Electronic Materials》2004,33(1):7-13
The interfacial interaction between the Sn-8.55Zn-0.5Ag-0.5Ga-0.1Al solder and three kinds of metallized substrates (Cu, Cu/Au,
and Cu/Ni-P/Au) does not form the Cu-Sn intermetallic compound (IMC). Continuous Cu-Zn and discontinuous Ag-Zn interfacial
IMC layers formed between the Cu and Sn-Zn-Ag-Ga-Al solder, while Cu-Zn and Au-Al-Zn IMCs formed on the Cu/Au substrate. Only
the Au-Al-Zn IMC formed at the interface when the electroless Ni-P deposit was the diffusion barrier between Cu and the Au
surface layer. 相似文献
5.
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
6.
Effect of Cr additions on interfacial reaction between the Sn-Zn-Bi solder and Cu/electroplated Ni substrates 总被引:2,自引:0,他引:2
Intermetallic compounds (IMCs) growth on the Sn-8Zn-3Bi (-Cr) solder joints with Cu and electroplated Ni substrates was investigated after aging at 150 °C. It was found that the IMCs were the Cu5Zn8 and Ni5Zn21 at the solder/Cu and solder/Ni interface, respectively. The IMCs growth rate at the Sn-8Zn-3Bi-Cr/Cu and Ni interface was slower than that at Sn-8Zn-3Bi/Cu interface (about 1/2 times) and Sn-8Zn-3Bi/Ni interface (about 1/4 times) during aging. The reason may be that Cr reacts with Zn and forms the Sn-Zn-Cr phase which block the diffusion of Zn atom to the interface and slow down the IMCs growth rate. 相似文献
7.
Electroless Ni-P layers with three different P contents (6.1 wt.%, 8.8 wt.%, and 12.3wt.%) were deposited on copper (Cu) substrates.
Multilayered samples of Sn-3.5Ag/Ni-P/Cu stack were prepared and subjected to multiple reflows at 250°C. A tensile test was
performed to investigate the effect of P content on the solder joint strength. The low P samples exhibited the highest joint
strength after multiple reflows, while the strength of medium and high P samples decreased more rapidly. From interfacial
analysis, the Ni3Sn4 intermetallic compound (IMC) formed at the interface of low P sample was found to be more stable, while the one of medium
and high P samples spalled into the molten solder. The IMC spallation sped up the consumption of electroless Ni-P, leading
to the large formation of Cu-Sn IMCs. Fractographic and microstructural analyses showed that the degradation in solder joint
strength was due to the formation of layers of voids and growth of Cu-Sn IMCs between the solder and the Cu substrate. 相似文献
8.
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
9.
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
10.
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
11.
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
12.
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
13.
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
14.
The early interfacial reaction in the Sn-3.5Ag/Cu soldering system and the system’s premelting behavior were found and characterized
by differential scanning calorimetry incorporated into the reflow process. The results show that the early interfacial reaction
occurs by way of melting and wetting of the solder layer adjacent to the Cu substrate at a temperature nearly 4°C below the
actual melting point of Sn-3.5Ag solder due to solid-state diffusion of Cu atoms into the Sn-3.5Ag binary solder. Consequently,
the early interfacial reaction brings about formation of Cu-Sn intermetallic compounds (IMCs) at a temperature below the melting
point of Sn-3.5Ag, and a prolonged early interfacial reaction can lead to change of the Cu-Sn IMC morphology from planar-like
to scallop-like and promote excessive growth of IMCs at the interface. 相似文献
15.
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
16.
In general, formation and growth of intermetallic compounds (IMCs) play a major role in the reliability of the solder joint
in electronics packaging and assembly. The formation of Cu-Sn or Ni-Sn IMCs have been observed at the interface of Sn-rich
solders reacted with Cu or Ni substrates. In this study, a nanoindentation technique was employed to investigate nanohardness
and reduced elastic moduli of Cu6Sn5, Cu3Sn, and Ni3Sn4 IMCs in the solder joints. The Sn-3.5Ag and Sn-37Pb solder pastes were placed on a Cu/Ti/Si substrate and Ni foil then annealed
at 240°C to fabricate solder joints. In Sn-3.5Ag joints, the magnitude of the hardness of the IMCs was in the order Ni3Sn4>Cu6Sn5>Cu3Sn, and the elastic moduli of Cu6Sn5, Cu3Sn, and Ni3Sn4 were 125 GPa, 136 GPa, and 142 GPa, respectively. In addition, the elastic modulus of the Cu6Sn5 IMC in the Sn-37Pb joint was similar to that for the bulk Cu6Sn5 specimen but less than that in the Sn-3.5Ag joint. This might be attributed to the strengthening effect of the dissolved
Ag atoms in the Cu6Sn5 IMC to enhance the elastic modulus in the Sn-3.5Ag/Cu joint. 相似文献
17.
Law C.M.T. Wu C.M.L. Yu D.Q. Li M. Chi D.Z. 《Advanced Packaging, IEEE Transactions on》2005,28(2):252-258
Rare earth (RE) elements, primarily La and Ce, were doped in Sn-Zn solder to improve its properties such as wettability. The interfacial microstructure evolution and shear strength of the Sn-9Zn and Sn-9Zn-0.5RE (in wt%) solder bumps on Au/Ni/Cu under bump metallization (UBM) in a ball grid array (BGA) were investigated after thermal aging at 150 /spl deg/C for up to 1000 h. In the as-reflowed Sn-9Zn solder bump, AuSn/sub 4/ intermetallic compounds (IMCs) and Au-Zn circular IMCs formed close to the solder/UBM interface, together with the formation of a Ni-Zn-Sn ternary IMC layer of about 1 /spl mu/m in thickness. In contrast, in the as-reflowed Sn-9Zn-0.5RE solder bump, a spalled layer of Au-Zn was formed above the Ni layer. Sn-Ce-La and Sn-Zn-Ce-La phases were found near the interface at positions near the surface of the solder ball. Upon thermal aging at 150 /spl deg/C, the concentration of Zn in the Ni-Zn-Sn ternary layer of Sn-9Zn increased with aging time. For Sn-9Zn-0.5RE, the Au-Zn layer began to dissolve after 500 h of thermal aging. The shear strength of the Sn-9Zn ball was decreased after the addition of RE elements, although it was still higher than that of the Sn-37Pb and Sn-36Pb-2Ag Pb-bearing solders. The fracture mode of the Sn-9Zn system was changed from ductile to partly brittle after adding the RE elements. This is mainly due to the presence of the brittle Au-Zn layer. 相似文献
18.
Lijuan Liu 《Microelectronics Reliability》2010,50(2):251-257
Electromigration behavior in a one-dimensional Cu/Sn-8Zn-3Bi/Cu solder joint structure was investigated in ambient with a current density of 3.5 × 104 A/cm2 at 60 °C. Due to the compressive stress induced by volume expansion resulting from Cu-Zn intermetallic compound (IMC) growth, Cu5Zn8 IMC layers were squeezed out continuously along IMC/Cu interfaces at both the anode and the cathode with increasing the current stressing time, which was not only driven by the concentration gradient, but also accelerated by the electromigration. And a few voids propagated and formed at the anode and the cathode solder/IMC interfaces during electromigration. Additionally, Sn hillocks occurred in the bulk solder, and Sn hillocks formed at the anode side were larger than those at the cathode side. 相似文献
19.
The morphology and growth kinetics of intermetallic compounds (IMCs) formed at the interfaces between liquid Sn-8Zn-3Bi solders
and nickel substrates in the temperature range from 225°C to 400°C are investigated for the applications in bonding recycled
sputtering targets to their backing plates. The results show that a continuous single layer of Ni5Zn21 IMC appears at temperatures below 325°C, while a double layer containing Ni5Zn21 and Ni35Zn22Sn43 IMCs is formed at temperatures above 325°C. In both cases, the growth kinetics of IMCs is interface-controlled. During the
growth of IMCs, their reaction fronts migrate in the direction of the solder much more rapidly than toward the nickel substrate,
and erosion of the Ni substrate is quite slight. 相似文献
20.
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