Effect of Joint Size on Microstructure and Growth Kinetics of Intermetallic Compounds in Solid-Liquid Interdiffusion Sn3.5Ag/Cu-Substrate Solder Joints

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
Ousama M. Abdelhadi ◽  
Leila Ladani
Keyword(s):  
Growth Rate ◽  
Intermetallic Compounds ◽  
Rate Constants ◽  
Solder Joints ◽  
Intermetallic Layer ◽  
Cu Substrate ◽  
Soldering Time ◽  
Diffusion Controlled ◽  
Solid Liquid ◽  
Intermetallic Layers

The effect of joint size on the interfacial reaction in the Sn3.5Ag/Cu-substrate soldering system was examined. An experiment was conducted in which parameters such as bonding time, temperature, and pressure were varied at multiple levels. The morphology and thickness of all intermetallic compounds (IMC) were analyzed using the scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) techniques. An examination of the microstructures of solder joints of different sizes revealed that the size of the solder joint has no effect on the type of IMCs formed during the process. It was found that the joint size significantly affected the thickness of the intermetallic layers. The Cu3Sn intermetallic layers formed in the smaller sized solder joints were found to be thicker than those in the larger sized solder joints. In all specimen sizes, the increase in the thickness of Cu3Sn intermetallic layers with soldering time was found to obey a parabolic relationship. Additionally, for the cases when eutectic solder is available in the joints, a similar soldering time and temperature dependency were found for the Cu6Sn5 IMC phase. The intermetallic growth of the Cu3Sn phase was under a volume-diffusion controlled mechanism. The growth rate constants and activation energies of intermetallic layers were also reported for different joint thicknesses. Furthermore, the growth rate constants of the Cu3Sn intermetallic layer were found to depend upon the size of the joints.

scholarly journals Dynamic Observation of Interfacial IMC Evolution and Fracture Mechanism of Sn2.5Ag0.7Cu0.1RE/Cu Lead-Free Solder Joints during Isothermal Aging

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 831 ◽  
Author(s):  
Di Zhao ◽  
Keke Zhang ◽  
Ning Ma ◽  
Shijie Li ◽  
Chenxiang Yin ◽  
...  
Keyword(s):  
Growth Rate ◽  
Fracture Mechanism ◽  
Isothermal Aging ◽  
Solder Joints ◽  
Diffusion Mechanism ◽  
Bulk Diffusion ◽  
Cu Substrate ◽  
Dynamic Observation ◽  
Free Solder ◽  
The Relationship

Dynamic observation of the microstructure evolution of Sn2.5Ag0.7Cu0.1RE/Cu solder joints and the relationship between the interfacial intermetallic compound (IMC) and the mechanical properties of the solder joints were investigated during isothermal aging. The results showed that the original single scallop-type Cu6Sn5 IMC gradually evolved into a planar double-layer IMC consisting of Cu6Sn5 and Cu3Sn IMCs with isothermal aging. In particular, the Cu3Sn IMC grew towards the Cu substrate and the solder seam sides; growth toward the Cu substrate side was dominant during the isothermal aging process. The growth of Cu3Sn IMC depended on the accumulated time at a certain temperature, where the growth rate of Cu3Sn was higher than that of Cu6Sn5. Additionally, the growth of the interfacial IMC was mainly controlled by bulk diffusion mechanism, where the activation energies of Cu6Sn5 and Cu3Sn were 74.7 and 86.6 kJ/mol, respectively. The growth rate of Cu3Sn was slightly faster than that of Cu6Sn5 during isothermal aging. With increasing isothermal aging time, the shear strength of the solder joints decreased and showed a linear relationship with the thickness of Cu3Sn. The fracture mechanism of the solder joints changed from ductile fracture to brittle fracture, and the fracture pathway transferred from the solder seam to the interfacial IMC layer.

Effect of nickel (Ni) on the growth rate of Cu6Sn5 intermetallic compounds between Sn–Cu–Bi solder and Cu substrate

2018 ◽  
Vol 30 (3) ◽  
pp. 2186-2191 ◽  
Author(s):  
He Gao ◽  
Fuxiang Wei ◽  
Yanwei Sui ◽  
Jiqiu Qi ◽  
Yezeng He ◽  
...  
Keyword(s):  
Growth Rate ◽  
Intermetallic Compounds ◽  
Cu Substrate

Effects of Bismuth Content on the Microstructure, Shear Strength and Thermal Properties of Sn-0.7Cu-0.05Ni Solder Joints

2020 ◽  
Vol 982 ◽  
pp. 115-120
Author(s):  
Phairote Sungkhaphaitoon ◽  
Tanyaporn Suwansukho
Keyword(s):  
Shear Strength ◽  
Thermal Properties ◽  
Solder Joint ◽  
Intermetallic Compounds ◽  
Interfacial Layer ◽  
Solder Joints ◽  
Peak Temperature ◽  
Cu Substrate ◽  
Bismuth Content ◽  
Pasty Range

The effects of bismuth content on the microstructure, shear strength and thermal properties of Sn-0.7Cu-0.05Ni solder joints were investigated. Adding 2 wt% elemental Bi to Sn-0.7Cu-0.05Ni solder joints reduced peak temperature by about 6.7 °C, increased pasty range by 4.2 °C and raised undercooling by 3.1 °C. The microstructure of the interfacial layer between solder and Cu substrate was composed of (Cu,Ni)6Sn5 and (Cu,Ni)3Sn intermetallic compounds (IMCs). The solder joint included a phase of SnBi and Cu6Sn5 IMCs. The addition of elemental Bi increased shear strength and suppressed the growth of IMCs in the interfacial layer of the solder joints.

Interfacial reactions of Sn–Cu and Sn–Pb–Ag solder with Au/Ni during extended time reflow in ball grid array packages

2004 ◽  
Vol 19 (10) ◽  
pp. 2897-2904 ◽  
Author(s):  
M.N. Islam ◽  
Y.C. Chan ◽  
A. Sharif
Keyword(s):  
Growth Rate ◽  
Shear Strength ◽  
Solder Joint ◽  
Intermetallic Compounds ◽  
Solder Joints ◽  
Interfacial Reactions ◽  
Extended Time ◽  
Reflow Time ◽  
Ternary Intermetallic Compounds ◽  
Ball Grid Array Packages

Lead-free solders with high Sn content cause excessive interfacial reactions at the interface with under-bump metallization during reflow. The interface formed after reflow affects the reliability of the solder joint. For this paper, we investigated the interfacial reactions of Sn0.7Cu and Sn36Pb2Ag solder on electrolytic Ni layer for different reflow times. The traditionally used Sn36Pb2Ag solder was used as a reference. It was found that during as-reflowed, the formation of Cu-rich Sn–Cu–Ni ternary intermetallic compounds (TIMCs) at the interface of Sn0.7Cu solder with electrolytic Ni is much quicker, resulting in the entrapment of some Pb (which is present as impurity in the Sn–Cu solder) rich phase in the TIMCs. During extended time of reflow, high (>30 at.%), medium (30-15 at.%) and low (<15 at.%) Cu TIMCs formed at the interface. The amount of Cu determined the growth rate of TIMCs. Cu-rich TIMCs had higher growth rate and consumed more Ni layer. By contrast, the growth rate of the Ni–Sn binary intermetallic compounds (BIMCs) in the Sn36Pb2Ag solder joint was slower, and the Ni–Sn BIMC was more stable and adherent. The dissolution rate of electrolytic Ni layer for Sn0.7Cu solder joint was higher than the Sn36Pb2Ag solder joints. Less than 3 μm of the electrolytic Ni layer was consumed during molten reaction by the higher Sn containing Sn0.7Cu solder in 180 min at 250 °C. The shear strength of Sn–Pb–Ag solder joints decreased within 30 min of reflow time from 1.938 to 1.579 kgf due to rapid formation of ternary Ni–Sn–Au compounds on the Ni–Sn BIMCs. The shear strength of Sn0.7Cu solder joint is relatively stable from 1.982 to 1.861 kgf during extended time reflow. Cu prevents the resettlement of Au at the interface. The shear strength does not depend on the thickness of intermetallic compounds (IMCs) and reflow time. Ni/Sn–Cu solder system has higher strength and can be used during prolonged reflow.

Effect of Ni Addition on the Formation and Growth of Intermetallic Compound at Eutectic SnBi/Cu Interface

2010 ◽  
Vol 160-162 ◽  
pp. 709-714
Author(s):  
Tian You Kang ◽  
Yu Yan Xiu ◽  
Bo Xu ◽  
Chun Zhong Liu ◽  
Wei Ping Tong
Keyword(s):  
Growth Rate ◽  
Intermetallic Compound ◽  
Solder Alloy ◽  
Aging Process ◽  
Growth Behavior ◽  
Cu Substrate ◽  
Diffusion Controlled ◽  
Ni Addition ◽  
Cu3sn Layer

The reactions between Cu and the eutectic SnBi (Sn58wt.%Bi) solder alloy with and without 1wt.%Ni addition were investigated in this paper. After as-reflowed process, the IMCs formed in the Sn58wt.%Bi/Cu and Sn58wt.%Bi1wt.%Ni/Cu joints were Cu6Sn5 and (CuNi)6Sn5, respectively. During aging process, the thickness of the IMC layers formed at each solder/Cu joint increased, and a new layer Cu3Sn formed adjacent to the Cu substrate. It was found that 1wt.%Ni addition in Sn58wt.%Bi solder alloy could slightly enhance the growth rate of the total IMC layer, but effectively reduce the growth rate of Cu3Sn layer during aging process. The growth behavior of IMC layer for each joint followed the diffusion-controlled mechanism during aging.

Morphology and Intermetallics Study of (Sn-8Zn-3Bi)-1Ag Solder under Liquid-State Aging

2012 ◽  
Vol 620 ◽  
pp. 273-277 ◽  
Author(s):  
Nor Aishah Jasli ◽  
Hamidi Abd Hamid ◽  
Ramani Mayappan
Keyword(s):  
Growth Rate ◽  
Electron Microscope ◽  
Liquid State ◽  
Intermetallic Layer ◽  
Intermetallic Phase ◽  
The Other ◽  
Ag Addition ◽  
Cu Substrate ◽  
X Ray ◽  
Scanning Electron

This study investigated the effect of Ag addition on the morphology and growth rate of Cu5Zn8, Cu6Sn5 and Cu3Sn intermetallics in the Sn-8Zn-3Bi solder. The solder was prepared by mixing 1wt% of Ag into 99wt% of Sn-8Zn-3Bi solder. The intermetallics were formed by liquid-state aging, whereby the solders were reacted on Cu substrate above the melting temperature of the solder. The reflow was done at 250°C and 270°C at various soldering times. A scanning electron microscope (SEM) was used to observe the morphology of the intermetallic phase and energy dispersive X-ray (EDX) was used to identify the elemental composition. The Sn-8Zn-3Bi solder reacting with Cu substrate formed a single Cu5Zn8 intermetallic layer with a flat structure. On the other hand, the reaction between (Sn-8Zn-3Bi)-1Ag solder and Cu substrate produces Cu6Sn5 intermetallic. This Cu6Sn5 intermetallic has a scallop structure. As the soldering time increases, a second layer, identified as Cu3Sn starts to grow. The thickness of the intermetallics increases with aging temperatures and time. The addition of Ag into the Sn-8Zn-3Bi solder has significantly suppressed the formation of Cu5Zn8 intermetallic and promoted the growth of Cu6Sn5 intermetallic.

Dependence of Cu/Sn and Cu/60Sn40Pb Solder Joint Strength on Diffusion Controlled Growth of Cu3Sn and Cu6Sn5

1984 ◽  
Vol 40 ◽  
Author(s):  
D. S. Dunn ◽  
T. F. Marinis ◽  
W. M. Sherry ◽  
C. J. Williams
Keyword(s):  
Growth Rate ◽  
Intermetallic Compounds ◽  
Isothermal Aging ◽  
Joint Strength ◽  
Tensile Tests ◽  
Square Root ◽  
Butt Joints ◽  
Substrate Orientation ◽  
Diffusion Controlled ◽  
Temperature Aging

AbstractThe growth of intermetallic compounds and the strength of Cu/ Sn and Cu/ 60Sn40Pb butt joints were studied as a function of isothermal aging. The effects of single-crystal (100), (110), and (111) oriented copper on the growth rates of Cu3Sn and Cu6Sn5 intermetallic compounds are characterized and the influence of elevated temperature aging on the tensile strength of butt joints analyzed. Substrate orientation appears to influence the growth rate. Metallographic measurements showed that the intermetallic compounds grew at a rate proportional to the square root of time. Tensile tests of aged butt joints revealed a more complex time dependence.

Enhanced Growth Kinetics of Intermetallic Compounds between Bi-Containing Sn-3.5Ag Solders and Cu Substrate during Aging

2005 ◽  
Vol 475-479 ◽  
pp. 2627-2630
Author(s):  
Soon Tae Kim ◽  
Joo Youl Huh
Keyword(s):  
Growth Rate ◽  
Intermetallic Compounds ◽  
Solder Alloy ◽  
Interfacial Reaction ◽  
Growth Kinetics ◽  
Cu Substrate ◽  
Reaction Barrier ◽  
Cu3sn Layer ◽  
Cu6sn5 Layer ◽  
Kinetics Of

The effect of adding Bi to a eutectic Sn-3.5Ag solder alloy on the growth kinetics of the intermetallic compounds (IMCs) in solder/Cu joints was examined at the aging temperatures of 130°C, 150°C and 180°C. At 150°C and 180°C, the growth rate of the Cu6Sn5 layer was significantly enhanced, but that of the Cu3Sn layer was rather reduced with increasing Bi content up to 12 wt.%. At 130°C, however, both the η and ε layers appeared to grow faster as the Bi content in the solder was increased to 12 wt.%. These results suggest that the accumulation of Bi ahead of the Cu6Sn5 layers can affect not only the interfacial reaction barrier but also the local thermodynamics at the interface between the Cu6Sn5 layer and the solder.

Effects of Different Fluxes on the Spreadability of Zn-20Sn Solders

2011 ◽  
Vol 337 ◽  
pp. 546-549
Author(s):  
Yang Yang Sheng ◽  
Yan Fu Yan ◽  
Kuai Le Zhao ◽  
Zhi Wei Xu
Keyword(s):  
Intermetallic Compounds ◽  
Solder Joints ◽  
Middle Layer ◽  
Cu Substrate ◽  
Medium Activity

The spreadability of Zn-20Sn solders on Cu substrate was researched by using self-made flux, silver brazing 102 and medium activity rosin (RMA), and the characteristics of intermetallic compounds the appearance of solder joints were compared and analyzed at soldering joints. Results indicated that Zn-20Sn solders exhibited excellent spreadability by using self-made flux. A shoot IMC layer was closed to the solder while a flat IMC layer was presenting adjacent to the Cu substrate and the middle layer. Moreover, the characteristics of IMC and the appearances of soldered joints varied by using different fluxes.

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