scholarly journals The In-Situ Observation of Grain Rotation and Microstructure Evolution Induced by Electromigration in Sn-3.0Ag-0.5Cu Solder Joints

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5497
Author(s):  
Xing Fu ◽  
Min Liu ◽  
KeXin Xu ◽  
Si Chen ◽  
YiJun Shi ◽  
...  
Keyword(s):  
Solder Joints ◽  
Flow Direction ◽  
Electron Flow ◽  
Critical Role ◽  
In Situ Observation ◽  
Fast Diffusion ◽  
Electron Backscattered Diffraction ◽  
Grain Rotation ◽  
Current Stressing

The in-situ observation of Sn-3.0Ag-0.5Cu solder joints under electromigration was conducted to investigate the microstructure and grain orientation evolution. It was observed that there was a grain rotation phenomenon during current stressing by in-situ electron backscattered diffraction (EBSD). The rotation angle was calculated, which indicated that the grain reorientation led to the decrease of the resistance of solder joints. On the other hand, the orientation of β-Sn played a critical role in determining the migration of Cu atoms in solder joints under current stressing migration. When the angle between the electron flow direction and the c-axis of Sn (defined as α) was close to 0°, massive Cu6Sn5 intermetallic compounds were observed in the solder bulk; however, when α was close to 90°, the migration of the intermetallic compound (IMC) was blocked but many Sn hillocks grew in the anode. Moreover, the low angle boundaries were the fast diffusion channel of Cu atoms while the high grain boundaries in the range of 55°–65° were not favorable to the fast diffusion of Cu atoms.

In-situ observation of material migration in flip-chip solder joints under current stressing

2006 ◽  
Vol 35 (10) ◽  
pp. 1781-1786 ◽  
Author(s):  
C. M. Tsai ◽  
Yi-Shao Lai ◽  
Y. L. Lin ◽  
C. W. Chang ◽  
C. R. Kao
Keyword(s):  
Flip Chip ◽  
Solder Joints ◽  
In Situ Observation ◽  
Current Stressing ◽  
Material Migration

Effects of crystallographic orientation of Sn on electromigration behavior

2010 ◽  
Vol 2010 (1) ◽  
pp. 000792-000797 ◽  
Author(s):  
Kiju Lee ◽  
Keun-Soo Kim ◽  
Kimihiro Yamanaka ◽  
Yutaka Tsukada ◽  
Soichi Kuritani ◽  
...  
Keyword(s):  
Crystallographic Orientation ◽  
Flip Chip ◽  
Current Flow ◽  
Electron Flow ◽  
Test Sample ◽  
Microstructural Change ◽  
Cathode Side ◽  
Fast Diffusion ◽  
Applied Current ◽  
Current Stressing

Electromigration behavior of SAC flip-chip joints with respect to the crystallographic orientation of Sn grains was investigated. The test sample had direct contact of Sn-3.0wt% Ag-0.5wt% Cu on Cu-OSP (organic surface preservative) and the applied current density was 15 kA/cm2 at 160 °C. Without current stressing, no microstructural change depending on the crystallographic orientation of Sn was observed. With current stressing, however, the bumps showed the substantial microstructural changes with respect to the crystallographic orientation of Sn. When the orientation of the current flow was parallel to the c-axis, fast failure of the bumps occurred due to the massive dissolution of the Cu electrode on the cathode side caused by the fast diffusion of Cu atoms along the c-axis of Sn grains while only a slight microstructural change was observed when the c-axis of Sn grains was perpendicular to the electron flow.

scholarly journals In-situ Study of Electromigration-induced Grain Rotation in Pb-free Solder Joint by Synchrotron Microdiffraction

2008 ◽  
Vol 1116 ◽  
Author(s):  
Kai Chen ◽  
Nobumichi Tamura ◽  
King-Ning Tu
Keyword(s):  
Solder Joint ◽  
Flip Chip ◽  
Solder Joints ◽  
Electric Resistance ◽  
Grain Rotation ◽  
X Ray ◽  
In Situ Study ◽  
Free Solder ◽  
Interconnect Lines

AbstractThe rotation of Sn grains in Pb-free flip chip solder joints hasn't been reported in literature so far although it has been observed in Sn strips. In this letter, we report the detailed study of the grain orientation evolution induced by electromigration by synchrotron based white beam X-ray microdiffraction. It is found that the grains in solder joint rotate more slowly than in Sn strip even under higher current density. On the other hand, based on our estimation, the reorientation of the grains in solder joints also results in the reduction of electric resistivity, similar to the case of Sn strip. We will also discuss the reason why the electric resistance decreases much more in strips than in the Sn-based solders, and the different driving force for the grain growth in solder joint and in thin film interconnect lines.

scholarly journals In situ observation of thermal-driven degradation and safety concerns of lithiated graphite anode

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xiang Liu ◽  
Liang Yin ◽  
Dongsheng Ren ◽  
Li Wang ◽  
Yang Ren ◽  
...  
Keyword(s):  
Thermal Degradation ◽  
Rational Design ◽  
Degradation Mechanism ◽  
Critical Role ◽  
Lithium Ion ◽  
Graphite Anode ◽  
In Situ Observation ◽  
Lithium Storage ◽  
Safety Hazards

AbstractGraphite, a robust host for reversible lithium storage, enabled the first commercially viable lithium-ion batteries. However, the thermal degradation pathway and the safety hazards of lithiated graphite remain elusive. Here, solid-electrolyte interphase (SEI) decomposition, lithium leaching, and gas release of the lithiated graphite anode during heating were examined by in situ synchrotron X-ray techniques and in situ mass spectroscopy. The source of flammable gas such as H2 was identified and quantitively analyzed. Also, the existence of highly reactive residual lithium on the graphite surface was identified at high temperatures. Our results emphasized the critical role of the SEI in anode thermal stability and uncovered the potential safety hazards of the flammable gases and leached lithium. The anode thermal degradation mechanism revealed in the present work will stimulate more efforts in the rational design of anodes to enable safe energy storage.

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