Prediction of Electromigration Failure of Solder Joints and Its Sensitivity Analysis

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Lihua Liang ◽  
Yuanxiang Zhang ◽  
Yong Liu
Keyword(s):  
Sensitivity Analysis ◽  
Solder Joints ◽  
Void Nucleation ◽  
High Current Density ◽  
Atomic Density ◽  
Time To Failure ◽  
Chip Scale Package ◽  
Simulation Results ◽  
Reliability Issue ◽  
Electron Wind

Electromigration (EM) in solder joints under high current density has become a critical reliability issue for the future high density microelectronic packaging. This paper presents atomic density redistribution algorithm for predicting electromigration induced void nucleation and growth in solder joints of Chip Scale Package (CSP) structure. The driving force for electromigration induced failure considered here includes the electron wind force, stress gradients, temperature gradients, as well as the atomic density gradient, which were neglected in many of the existing studies on electromigration. The simulation results for void generation and time to failure (TTF) are discussed and correlated with the previous test results. EM sensitivity analysis is also performed to investigate the effect of EM parameters and mechanical properties of material on electromigration failure. The simulation results indicated that the atomic density on the activation energy is quite sensitive, and the mechanical material parameters have no impact on EM sensitivity of normalized atomic density.

Electromigration and thermomigration behavior of flip chip solder joints in high current density packages

2008 ◽  
Vol 23 (9) ◽  
pp. 2333-2339 ◽  
Author(s):  
D. Yang ◽  
Y.C. Chan ◽  
B.Y. Wu ◽  
M. Pecht
Keyword(s):  
Flip Chip ◽  
Solder Joints ◽  
High Current Density ◽  
Dominant Role ◽  
Current Crowding ◽  
Wind Force ◽  
Cross Sectional ◽  
Ambient Temperatures ◽  
Atomic Flux ◽  
Electron Wind

The electromigration and thermomigration behavior of eutectic tin-lead flip chip solder joints, subjected to currents ranging from 1.6 to 2.0 A, at ambient temperatures above 100 °C, was experimentally and numerically studied. The temperature at the chip side was monitored using both a temperature coefficient of resistance method and a thermal infrared technique. The electron wind force and thermal gradient played the dominant role in accelerated atomic migration. The atomic flux of lead due to electromigration and thermomigration was estimated for comparison. At the current crowding region, electromigration induced a more serious void accumulation as compared with thermomigration. Also, because of different thermal dissipations, a morphological variation was detected at different cross-sectional planes of the solder joint during thermomigration.

Evaluation of electromigration in flip-chip solder joints

2011 ◽  
Vol 2011 (1) ◽  
pp. 000979-000984 ◽  
Author(s):  
Hyun-Kyu Lee ◽  
Yong-Chul Chu ◽  
Myung-Ho Chun ◽  
Sang-Ho Jeon ◽  
Jung-Ug Kwak ◽  
...  
Keyword(s):  
Electric Current ◽  
Flip Chip ◽  
Solder Joints ◽  
Cathode Side ◽  
Time To Failure ◽  
Chip Technology ◽  
Solder Bumps ◽  
Solder Balls ◽  
Initial Resistance ◽  
Reliability Issue

The flip-chip solder joint has become one of the most important technologies of high-density packaging in the microelectronics industry. But, electromigration has become a critical reliability issue in flip-chip technology. Because the dimensions of solder joints are expected to decrease and current density is expected to increase. This study is about electromigration of flip-chip solder joints, we evaluated many kinds of solder balls such as SnAgCu, SnCu and so on in flip chip package. The lifetime against electromigration was defined the fail from the value of resistance with electric current reaches 1.5 times of that of initial resistance with electric current for. In solder bumps with electric current, since the atoms composed of the solder bump and UBM move in the direction of electron flows, the IMC was accumulated on the anode side. Meanwhile, the IMC disappeared in the cathode side, and the voids were formed. In the solder bumps without electric current, the IMC gradually grew on both sides. SnAgCu had better lifetime than SnCu, and different time-to-failure caused by different crystallographic orientation of Sn. And various dopants in SnCu had a different EM lifetime each other.

Effect of Current Direction on the Reliability of Different Capped Cu Interconnects

2005 ◽  
Vol 863 ◽  
Author(s):  
C. L. Gan ◽  
C. Y. Lee ◽  
C. K. Cheng ◽  
J. Gambino
Keyword(s):  
Failure Analysis ◽  
Current Flow ◽  
Void Nucleation ◽  
Electrical Current ◽  
Nucleation Site ◽  
Time To Failure ◽  
Current Direction ◽  
Electron Current ◽  
Electrical Current Flow ◽  
Better Than

AbstractThe reliability of Cu M1-V1-M2-V2-M3 interconnects with SiN and CoWP cap layers was investigated. Similar to previously reported results, the reliability of CoWP capped structures is much better than identical SiN capped structures. However, it was also observed that the reliability of CoWP capped interconnects was independent of the direction of electrical current flow. This phenomenon is different from what was observed for SiN capped structures, where M2 lines with electron current flow in the upstream configuration (“via-below”) have about three times larger median-time-to-failure than identical lines in the downstream configuration (“viaabove”). This is because the Cu/SiN interface is the preferential void nucleation site and provides the fastest diffusion pathway in such an architecture. Failure analysis has shown that fatal partially-spanned voids usually had formed directly below the via for “via-above” configuration, and fully-spanned voids occurred in the lines above the vias for “via-below” configuration.On the other hand, failure analysis for CoWP-coated Cu structures showed that partiallyspanned voids below the via do not cause fatal failures in the downstream configuration. This is because the CoWP layer is conducting, and thus able to shunt current around the void. As a result, a large fully-spanning void is required to cause a failure, just like the upstream configuration. Thus the lifetime of an interconnect with a conducting cap layer is independent of whether the current is flowing upstream or downstream.

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

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yanruoyue Li ◽  
Guicui Fu ◽  
Bo Wan ◽  
Zhaoxi Wu ◽  
Xiaojun Yan ◽  
...  
Keyword(s):  
Solder Joint ◽  
Thermal Stresses ◽  
Solder Joints ◽  
Void Formation ◽  
Model Parameters ◽  
Time To Failure ◽  
Current Crowding ◽  
Theoretical Derivation ◽  
Content Type ◽  
And Migration

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.

scholarly journals Sensitivity Analysis of Johnson-Cook Material Constants and Friction Coefficient Influence on Finite Element Simulation of Turning Inconel 718

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3121 ◽  
Author(s):  
Xiaoli Qiu ◽  
Xianqiang Cheng ◽  
Penghao Dong ◽  
Huachen Peng ◽  
Yan Xing ◽  
...  
Keyword(s):  
Residual Stress ◽  
Sensitivity Analysis ◽  
Finite Element ◽  
Friction Coefficient ◽  
Constitutive Model ◽  
Cutting Force ◽  
Inconel 718 ◽  
Coulomb Friction ◽  
Cutting Conditions ◽  
Simulation Results

The Johnson-Cook (J-C) constitutive model, including five material constants (A, B, n, C, m), and the Coulomb friction coefficient (μ) are critical preprocessed data in machining simulations. Before they become reliable preprocessed data, investigating these parameters’ effect on simulation results benefits parameter-selecting. This paper aims to investigate the different influence of five settings of the J-C constitutive equation and Coulomb friction coefficient on the turning simulation results of Inconel 718 under low-high cutting conditions, including residual stress, chip morphology, cutting force and temperature. A three-dimensional (3-D) finite element model was built, meanwhile, the reliability of the model was verified by comparing the experiment with the simulation. Sensitivity analysis of J-C parameters and friction coefficient on simulation results at low-high cutting conditions was carried out by the hybrid orthogonal test. The results demonstrate that the simulation accuracy of Inconel 718 is more susceptible to strain hardening and thermal softening in the J-C constitutive model. The friction coefficient only has significant effects on axial and radial forces in the high cutting condition. The influences of the coefficient A, n, and m on the residual stress, chip thickness, cutting force and temperature are especially significant. As the cutting parameters increase, the effect of the three coefficients will change visibly. This paper provides direction for controlling simulation results through the adjustment of the J-C constitutive model of Inconel 718 and the friction coefficient.

Predicting formulae for effective length of counterpoise wires buried in ionized, dispersive and inhomogeneous soils

2020 ◽  
Vol 39 (6) ◽  
pp. 1375-1391
Author(s):  
Seyyed Sajjad Sajjadi ◽  
Saeed Reza Ostadzadeh
Keyword(s):  
Sensitivity Analysis ◽  
Transmission Line ◽  
Design Methodology ◽  
Effective Length ◽  
Transmission Line Model ◽  
Line Model ◽  
Content Type ◽  
Dispersion Effects ◽  
Simulation Results

Purpose The purpose of this paper is to investigate the ionization and dispersion effects in combination with the inhomogeneity of soil simultaneously on the effective lengths of counterpoise wires. Design/methodology/approach Improved multi-conductor transmission line model is used for computing effective length of counterpoise wires considering all aspects of soils. Findings The simulation results show that the ionization and dispersion effects simultaneously results in placing the effective length between situations where only one effect is considered. Also, predicting formulae for effective length of counterpoise wires considering all effects are proposed. Originality/value A sensitivity analysis on the effective lengths of counterpoise wires considering all aspects of soils is carried out.

The coupling effects of thermal cycling and high current density on Sn58Bi solder joints

2012 ◽  
Vol 48 (6) ◽  
pp. 2318-2325 ◽  
Author(s):  
Yong Zuo ◽  
Limin Ma ◽  
Sihan Liu ◽  
Ting Wang ◽  
Fu Guo ◽  
...  
Keyword(s):  
Thermal Cycling ◽  
Current Density ◽  
Solder Joints ◽  
High Current Density ◽  
High Current ◽  
Coupling Effects

Risk Management of Construction Schedule by PERT with Monte Carlo Simulation

2014 ◽  
Vol 548-549 ◽  
pp. 1646-1650 ◽  
Author(s):  
Yang Liu ◽  
Yan Li
Keyword(s):  
Sensitivity Analysis ◽  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Critical Path ◽  
Total Duration ◽  
Control Points ◽  
Schedule Management ◽  
Simulation Results ◽  
Critical Paths ◽  
Construction Schedule

It has been proved that the construction schedule management was an uncertain problem. Traditional CPM method was a good way to define the total duration and critical paths but can not solve uncertainty. The paper use CPM to define the duration and critical path firstly, then defined the parameters with Delphi and make Monte Carlo simulation. Through simulation results, it is found that the probability to finish the work on time was only 35.3%. The following step is to make sensitivity analysis, through the calculation, the work which has large influence was found and treat as key control points. It is proved that Monte Carlo simulation is useful to solve the problem of construction schedule management.

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