scholarly journals Interface Growth and Void Formation in Sn/Cu and Sn0.7Cu/Cu Systems

2018 ◽  
Vol 8 (12) ◽  
pp. 2703 ◽  
Author(s):  
Jieshi Chen ◽  
Yongzhi Zhang ◽  
Zhishui Yu ◽  
Peilei Zhang ◽  
Wanqin Zhao ◽  
...  
Keyword(s):  
Intermetallic Compounds ◽  
High Purity ◽  
Void Formation ◽  
Free Interface ◽  
Fine Grain ◽  
Interface Growth ◽  
Imcs Growth ◽  
Cu3sn Layer ◽  
Electroplating Process ◽  
Pure Sn

In this work, the effects of electroplated Cu (EP Cu) and Cu addition (0.7%) in Sn solder on the intermetallic compounds (IMCs) growth and void formation were clarified by comparison with solder joints comprising of high purity Cu (HP Cu) substrate and pure Sn solder. After aging processes, a new IMC, Cu3Sn, was formed at the interface, in addition to Cu6Sn5 formed in the as-soldered joints. The EP Cu and Cu addition (0.7%) both had limited effects on the total IMCs thickness. However, the effects varied on the growth behaviors of different IMCs. Comparing to the void-free interface between Sn and HP Cu, a large number of voids were observed at the Cu3Sn/Cu interface in Sn/EP Cu joints. The formation of these voids may be induced by the impurities and fine grain, which were introduced during the electroplating process. The addition of Cu suppressed the inter-diffusion of Cu and Sn at the interface. Consequently, the growth of the Cu3Sn layer and formation of voids were suppressed.

Precise Quantitative Evaluation of Nano-Ordered Intermetallic Compounds in Sn-3.0Ag-0.5Cu Lead-Free Solder Bump by Using TEM

2008 ◽  
Vol 47-50 ◽  
pp. 907-911
Author(s):  
Chang Woo Lee ◽  
Y.S. Shin ◽  
J.H. Kim
Keyword(s):  
Intermetallic Compounds ◽  
Flip Chip ◽  
Solder Bump ◽  
Lead Free Solder ◽  
Growth Behaviour ◽  
Sic Particles ◽  
Imcs Growth ◽  
Ordered Intermetallic ◽  
Free Solder ◽  
The One

The growth behaviour of the intermetallic compounds (IMCs) in Pb-free solder bump is investigated. The Pb-free micro-bump, Sn-50%Bi, was fabricated by binary electroplating for flip-chip bond. The diameter of the bump is about 506m and the height is about 60 6m. In order to increase the reliability of the bonding, it is necessary to protect the growth of the IMCs in interface between Cu pad and the solder bump. For control of IMCs growth, SiC particles were distributed in the micro-solder bump during electroplating. The thickness of the IMCs in the interface was estimated by FE-SEM, EDS, XRF and TEM. From the results, The IMCs were found as Cu6Sn5 and Cu3Sn. The thickness of the IMCs decreases with increase the amount of SiC particles until 4 g/cm2. The one candidate of the reasons is that the SiC particles could decrease the area which be reacted between the solder and Cu layer. And another candidate is that the particle can make to difficult inter-diffusion within the interface.

Morphology of wetting reactions of SnPb alloys on Cu as a function of alloy composition

1998 ◽  
Vol 13 (1) ◽  
pp. 37-44 ◽  
Author(s):  
C. Y. Liu ◽  
K. N. Tu
Keyword(s):  
Free Energy ◽  
Intermetallic Compound ◽  
Intermetallic Compounds ◽  
Driving Force ◽  
Alloy Composition ◽  
Wetting Angle ◽  
Compound Formation ◽  
Side Band ◽  
Intermetallic Compound Formation ◽  
Pure Sn

We have investigated the wetting angle, side band growth, and intermetallic compound formation of seven SnPb alloys on Cu ranging from pure Sn to pure Pb. The wetting angle has a minimum near the middle composition and increases toward pure Sn and pure Pb, but the side band growth has a maximum near the middle composition. The intermetallic compounds formed are Cu6Sn5 and Cu3Sn for the eutectic and high-Sn alloys, yet for the high-Pb alloys, only Cu3Sn can be detected. While no intermetallic compound forms between Cu and pure Pb, the latter nevertheless wets the former with an angle of 115°. The driving force of a wetting reaction, which may be affected by the free energy gain in compound formation, is discussed by assuming that rate of compound formation is fast.

Effect of Forging Temperature on Deformability and Structure Evolution of High Purity Aluminium during Multi-Directional Forging Process

2016 ◽  
Vol 877 ◽  
pp. 371-379 ◽  
Author(s):  
Qing Feng Zhu ◽  
Jia Wang ◽  
Lei Li ◽  
Chun Yan Ban ◽  
Zhi Hao Zhao ◽  
...  
Keyword(s):  
Grain Size ◽  
High Purity ◽  
Recrystallization Temperature ◽  
Structure Evolution ◽  
Inhomogeneous Deformation ◽  
Forging Process ◽  
Fine Grain ◽  
Sample Shape ◽  
Purity Aluminium ◽  
High Purity Aluminium

The effects of final forging temperatures on deformability and structure evolution of high purity aluminum during multi-directional forging process were investigated. The results showed that increasing the initial forging temperature is beneficial for controlling the sample shape in the initial forging passes. Recrystallization during the initial forging passes improves the deformability of the sample in the following low-temperature forging processes. An X-shape fine grain zone is formed in the sample due to the inhomogeneous deformation of multi-directional forging process. When the forging pass is 6, the final forging temperature has an important influence on the grain size in the fine grain zone. The grain size decreases from 302 μm to 60 μm with the final forging temperature decreasing from 310 °C to 65 °C. The X-shape fine grain zone caused by the inhomogeneous deformation cannot be eliminated by increasing the final forging temperature (even higher than the recrystallization temperature of high purity aluminium).

Morphology of instability of the wetting tips of eutectic SnBi, eutectic SnPb, and pure Sn on Cu

1995 ◽  
Vol 10 (3) ◽  
pp. 497-504 ◽  
Author(s):  
H.K. Kim ◽  
H.K. Liou ◽  
K.N. Tu
Keyword(s):  
Solder Joint ◽  
Surface Morphology ◽  
Intermetallic Compounds ◽  
Rough Surface ◽  
Environmental Issue ◽  
Wetting Angle ◽  
Angle Change ◽  
Microelectronics Industry ◽  
Pure Sn ◽  
Eutectic Snpb

The Pb-based solder used in microelectronics industry is becoming an environmental issue. To understand the wetting behavior of solders with and without Pb, we have studied the surface morphology and wetting reaction of eutectic SnBi, eutectic SnPb, and pure Sn on Cu through the measurements of wetting angle change and wetting tip stability by SEM and EDX. The wetting angle remains constant after the initial spread, but the eutectic SnPb/Cu continues to react and forms a reaction band in front of the solder edge as well as intermetallic compounds at the interface. For eutectic SnBi/Cu, there is no reaction at the wetting tip, and the wetting angle does not change much; however, the interfacial reaction between eutectic SnBi and Cu forms intermetallic compounds at the solder joint; the wetting tip is not in a static equilibrium. A rough surface and edge was observed on the eutectic SnBi/Cu joint, but the eutectic SnPb/Cu has a smoother surface and edge.

Effect of precipitate volume fraction on fracture toughness of extruded Mg–Zn alloys

2008 ◽  
Vol 23 (4) ◽  
pp. 1128-1135 ◽  
Author(s):  
Hidetoshi Somekawa ◽  
Yoshiaki Osawa ◽  
Alok Singh ◽  
Toshiji Mukai
Keyword(s):  
Fracture Toughness ◽  
Volume Fraction ◽  
Void Formation ◽  
Zinc Content ◽  
Precipitate Volume Fraction ◽  
Fine Grained ◽  
Grain Sizes ◽  
Fine Grain ◽  
Ductile Fracture Model ◽  
Zn Alloy

Four kinds of extruded Mg–X at.% Zn binary alloys (X = 1.9, 2.4, 3.0, and 3.4) were used to examine the effect of precipitate volume fraction on fracture toughness. All the alloys had fine grain sizes of 1–3 μm and fine sphere-shaped precipitates of 50–60 nm. The volume fraction of precipitates increased with additional zinc content. The results of mechanical property tests showed that the extruded Mg–2.4 at.% Zn alloy exhibited the best balance of strength and fracture toughness. One of the reasons was the different volume fraction of precipitates at the grain boundaries, which was the source of void formation. According to the fracture surface observations and ductile fracture model analysis, the volume fraction of precipitates of 2%–4% was shown to be enough to improve the fracture toughness for the fine-grained magnesium alloys; i.e., higher contents of zinc atoms were not needed to enhance the mechanical properties.

Containerless Automated Processing of High-Purity Intermetallic Compounds and Composites

1996 ◽  
Vol 11 (1) ◽  
pp. 119-136 ◽  
Author(s):  
T. S. Newport ◽  
B. F. Oliver ◽  
D. R. Johnson ◽  
R. D. Noebe
Keyword(s):  
Intermetallic Compounds ◽  
High Purity ◽  
Automated Processing

Fast Soldering Reactions on Au Foils

1996 ◽  
Vol 445 ◽  
Author(s):  
P.G. Kim ◽  
K.N. TU
Keyword(s):  
Intermetallic Compounds ◽  
Wetting Angle ◽  
High Solubility ◽  
Reflow Time ◽  
X Ray ◽  
Intermetallic Compound Growth ◽  
Wetting Behaviors ◽  
Pure Sn ◽  
Eutectic Snpb

AbstractWe have studied the wetting behaviors and interfacial reactions of Pb‐containing (63Sn‐37Pb, 95Pb‐5Sn) and Pb‐free solders (pure Sn, 96Sn‐4Ag, 57Bi‐43Sn, 77.2Sn‐20In‐2.8Ag) on Au foils in order to understand the role of Pb in Pb‐based solders. Surface morphology, wetting angle, and interfacial reaction of the solders were studied by Scanning Electron Microscopy (SEM) and Energy Dispersive X‐ray Analysis (EDX). Pb‐containing and Pb‐free solders (pure Sn, 96Sn‐4Ag, 77.2Sn‐20In‐2.8Ag) showed rough surfaces due to the precipitation of intermetallic compounds on the surface of the solder caps. The eutectic SnBi (57Bi‐43Sn) solder, however, showed a smoother surface. The wetting angle of the eutectic SnPb (63Sn‐37Pb), pure Sn, 96Sn‐4Ag, and 77.2Sn‐20In‐2.8Ag solders decreased significantly with reflow time, while the eutectic SnBi and 95Pb‐5Sn solders showed a much smaller decrease. A large amount of intermetallic compounds was formed throughout the entire region of the solder cap for the eutectic SnPb, 96Sn‐4Ag, 95Pb‐5Sn, and 77.2Sn‐20In‐2.8Ag, mainly due to the high solubility of Au in these solders. Slow intermetallic compound growth was observed for the eutectic SnBi solder.

scholarly journals Effects of Impurity on Void Formation at Interface between Sn-3.0Ag-0.5Cu and Cu Electroplated Film

2021 ◽  
Author(s):  
Ping-Chen Chiang ◽  
Yu-An Shen ◽  
Chih-Ming Chen
Keyword(s):  
Solder Joint ◽  
Thermal Aging ◽  
Solder Joints ◽  
Void Formation ◽  
Interfacial Structure ◽  
Joint Interface ◽  
Grain Texture ◽  
Cu Films ◽  
Impurity Control ◽  
Electroplating Process

Abstract Void formation is a critical reliability concern for solder joints in electronic packaging. The control of microstructures and impurity quantities in Cu electroplated films significantly affects the void formation at the joint interface, but the studies for their comparison are seldom. In this study, three Cu films (termed as A, B, and C) are fabricated using an electroplating process. The Cu A film has a facted grain texture embedded with twins while Cu B and C have a similar columnar texture. After thermal aging at 200°C for 1000 h, the SAC 305 (Sn-3.0Ag-0.5Cu) solder joints with Cu A and B exhibit a robust interfacial structure without voids. However, microstructural collapse is observed in the solder joint of SAC 305/Cu C, where many crevives parallel to the interface are formed. Based on the microanalysis, the concentration of impurity is higher in the Cu C film than those in Cu A and B. Moreover, discrete voids rather than continuous crevices are presented in the SAC305/Cu C system when the impurity concentration in Cu C is reduced. The findings demonstrate that the impurity control in the Cu electroplated film is critical for the control of void/crevice formation in the electronic solder joints.

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