Time 0 Void Evolution and Effect on Electromigration

Xu, Jiefeng; McCann, Scott; Wang, Huayan; Pham, V.D.; Cain, Stephen R.; Refai-Ahmed, Gamal; Park, S.B.

doi:10.1109/ectc.2019.00321

Cited by 5 publications

(3 citation statements)

References 11 publications

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“…The correction coefficient of current density c was determined to be equal to 7.24. Regarding the SAC305 material, the migration activation energy is 0.98 eV (Xu et al, 2019). Boltzmann's constant k = 8.5e-5eV/K and c = 7.24.…”

Section: Current Crowdingmentioning

confidence: 99%

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A study on the effects of electrical and thermal stresses on void formation and migration lifetime of Sn3.0Ag0.5Cu solder joints

Wan

et al. 2021

SSMT

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Purpose The purpose of this study is to investigate the effect of electrical and thermal stresses on the void formation of the Sn3.0Ag0.5Cu (SAC305) lead-free ball grid array (BGA) solder joints and to propose a modified mean-time-to-failure (MTTF) equation when joints are subjected to coupling stress. Design/methodology/approach The samples of the BGA package were subjected to a migration test at different currents and temperatures. Voltage variation was recorded for analysis. Scanning electron microscope and electron back-scattered diffraction were applied to achieve the micromorphological observations. Additionally, the experimental and simulation results were combined to fit the modified model parameters. Findings Voids appeared at the corner of the cathode. The resistance of the daisy chain increased. Two stages of resistance variation were confirmed. The crystal lattice orientation rotated and became consistent and ordered. Electrical and thermal stresses had an impact on the void formation. As the current density and temperature increased, the void increased. The lifetime of the solder joint decreased as the electrical and thermal stresses increased. A modified MTTF model was proposed and its parameters were confirmed by theoretical derivation and test data fitting. Originality/value This study focuses on the effects of coupling stress on the void formation of the SAC305 BGA solder joint. The microstructure and macroscopic performance were studied to identify the effects of different stresses with the use of a variety of analytical methods. The modified MTTF model was constructed for application to SAC305 BGA solder joints. It was found suitable for larger current densities and larger influences of Joule heating and for the welding ball structure with current crowding.

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Section: Current Crowdingmentioning

confidence: 99%

“…Regarding the SAC305 material, the migration activation energy is 0.98 eV (Xu et al , 2019). Boltzmann’s constant k = 8.5e-5eV/K and c = 7.24.…”

Section: Mttf Of Sac305 Ball Grid Array Solder Jointsmentioning

confidence: 99%

A study on the effects of electrical and thermal stresses on void formation and migration lifetime of Sn3.0Ag0.5Cu solder joints

Wan

et al. 2021

SSMT

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show abstract

“…It was found that when the macro void was close to the boundary of the solder ball, its influence on fatigue reliability became greater [ 11 ]. With an increase in void size, the sensitivity of durability to void location decreased gradually [ 12 ]. However, a void is not always harmful, especially a void far away from the corner of solder joints.…”

Section: Introductionmentioning

confidence: 99%

Effects of Voids on Thermal Fatigue Reliability of Solder Joints on Inner Rings in Ball Grid Array Packaging by Finite Element Analysis

Liu

et al. 2023

Micromachines

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Under alternating temperatures, the fatigue failure of solder balls caused by the mismatch of the thermal expansion coefficient is a key problem in a Ball Grid Array (BGA). However, the combined effects of the solder ball location and the size of voids within it can seriously affect the thermal fatigue reliability of BGA solder balls, which can be easily ignored by researchers. Firstly, the thermal fatigue reliability of the board-level solder balls was evaluated by a temperature cycling test of the BGA package at −20 °C–+125 °C. The experimental results showed that the thermal fatigue reliability of the outer ring’s solder joint was lower than that of the inner ring. Secondly, the reliability of the solder balls in the BGA package was studied under the same thermal cycling condition based on finite element analysis (FEA). The influences of voids on fatigue life were investigated. Generally, a linear correlation between the void content and the fatigue life of the inner rings’ solder balls could be identified with a gradually smoothed relationship for solder balls closer to the center. In addition, when the size of the void exceeded a critical volume, the inner ring’s solder ball with the void would fail before the outermost ring. The results of FEA showed that the critical void volume ratio from the second to fifth ring increased from 10.5% to 42.3%. This study provides a valuable reference for the influence of voids on the thermal fatigue reliability of BGA solder balls.

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A comparative study of thermal fatigue life of Eutectic Sn-Bi, Hybrid Sn-Bi/SAC and SAC solder alloy BGAs

Cai

Wang

et al. 2021

Microelectronics Reliability

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Time 0 Void Evolution and Effect on Electromigration

Cited by 5 publications

References 11 publications

A study on the effects of electrical and thermal stresses on void formation and migration lifetime of Sn3.0Ag0.5Cu solder joints

A study on the effects of electrical and thermal stresses on void formation and migration lifetime of Sn3.0Ag0.5Cu solder joints

Effects of Voids on Thermal Fatigue Reliability of Solder Joints on Inner Rings in Ball Grid Array Packaging by Finite Element Analysis

A comparative study of thermal fatigue life of Eutectic Sn-Bi, Hybrid Sn-Bi/SAC and SAC solder alloy BGAs

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