In situ observation of thermomigration of Sn atoms to the hot end of 96.5Sn-3Ag-0.5Cu flip chip solder joints

2011 ◽  
Vol 110 (12) ◽  
pp. 123525 ◽  
Author(s):  
Fan-Yi Ouyang ◽  
C.-L. Kao
Keyword(s):  
Flip Chip ◽  
Solder Joints ◽  
In Situ Observation

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

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 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.

Deformation and Strain Measurement of Flip-Chip Solder Bump Under In-Situ Thermal Loading

2009 ◽  
Author(s):  
Jae B. Kwak ◽  
Dong Gun Lee ◽  
Tung Nguyen ◽  
Seungbae Park
Keyword(s):  
Deformation Behavior ◽  
Flip Chip ◽  
Thermal Loading ◽  
Solder Bump ◽  
Solder Joints ◽  
Image Correlation ◽  
Solder Bumps ◽  
Comparison Results ◽  
Dic Technique

Thermo-mechanical behavior of solder joints, especially the solder bumps located at the chip corners where most failures usually occur was investigated. Digital Image Correlation (DIC) technique with optical microscope was adopted to quantify the deformation behavior and strains of a solder bump of flip-chip package subjected to thermal loading. A flip-chip specimen was cross-sectioned after manual polishing process followed by wet etching method in order to generate natural speckle patterns with high enough contrast on the measuring surface for employing DIC technique. The sample was placed in a miniature heating chamber and subjected to in-situ thermal loading from 25 °C to 100°C. During the heating, sequential microscopic images of the cross-sectioned surface of a solder bump were acquired, and the deformation behavior and strain distributions were successfully measured with submicron accuracy by applying DIC technique on the captured images. The computed full-field displacement fields clearly depicted both normal and shear deformation of the solder bump under the thermal loading. In addition, from the strain fields, it was observed that strains were mostly concentrated on the bottom portion of solder bump near the pad connected to substrate. In order to assess the thermo-mechanical strains of the flip-chip interconnections more quantitatively, the average strains of solder joints at different locations were also measured and compared to one another. By doing so, the strain trends of solder bumps were effectively analyzed with respect to the distance to neutral point (DNP). Finally, finite element analysis was conducted by simulating the thermal loading applied in the experiments, and comparison between the simulation and experimental results of displacements and strains was made. The comparison results exhibited satisfactory agreement, which ensured the validity of the experimental data and methodology. This study can further expedite the studies of electronic-package reliability through fatigue and crack failure analysis of the solder joints due to thermal cyclic loading.

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