COTS BGA Thermal Fatigue Test for Avionics Applications

2003 ◽  
Author(s):  
H. S. Fenger ◽  
T. E. Wong
Keyword(s):  
Fatigue Life ◽  
Solder Joint ◽  
Thermal Fatigue ◽  
Prediction Models ◽  
Thermal Environment ◽  
Temperature Cycling ◽  
Physical Analysis ◽  
Test Results ◽  
Conformal Coating ◽  
Design And Manufacturing

The objectives of the present studies are to design and test representative commercial off-the-shelf plastic encapsulated microcircuits, including various types of ball grid array (BGA) components, chip scale package, and flip chip over military thermal environment. The approach is to demonstrate the solder joint reliability performance of these components through the design of an electrical daisy-chain pattern printed wiring board (PWB) assembly test vehicle (TV), in which the design and manufacturing variables are included. The variables, including the types of PWBs, conformal coating, and BGA underfilled materials, with each having either two or three levels of variation are used to address test criteria and to construct 12 different types of TV configurations. All TV configurations are then subjected to temperature cycling tests (−55°C to +125°C) while continuously monitoring solder joint integrity. Based on the measured results, a destructive physical analysis is then conducted to further isolate the failure locations and determine the failure mechanisms of the solder joints. Based on the lesson-learned from the above TV, a second TV (defined as TV2) has been designed, constructed and tested. The four selected parameters in TV2 are BGA under-fill materials, conformal coating, solder pad sizes on PWB, and BGA rework, with each also having either two or three levels of variation. Test results from these two groups of TVs indicate that the influence of these design and manufacturing parameters on fatigue life is dependent on the particular package, in some instances improving the fatigue life tenfold. All these test results are recommended to be used for calibrating BGA solder joint thermal fatigue life prediction models, which will be presented in other publications.

Thermal Fatigue Life Determination of CCGA Interconnect Using a Simple Method

2007 ◽  
Author(s):  
T. E. Wong ◽  
C. Chu
Keyword(s):  
Fatigue Life ◽  
Solder Joint ◽  
Prediction Model ◽  
Thermal Fatigue ◽  
Life Prediction ◽  
Temperature Cycling ◽  
Test Results ◽  
Electronic Package ◽  
Thermal Fatigue Life ◽  
Life Prediction Model

A simplified method was developed to determine the fatigue life of a ceramic column grid array (CCGA) solder joint when exposed to thermal environments. The CCGA package with 90Pb/10Sn solder columns is soldered onto the printed circuit board with a tin-lead solder paste. Failure of the solder joint occurs at the CCGA solder column. A closed-form solution with the equilibrium of displacements of electronic package assembly was first derived to calculate the solder joint strains during the temperature cycling. In the calculation, an iteration technique was used to obtain a convergent solution in the solder strains, and the elastic material properties were used for all the electronic package assembly components except for the solder materials, which used elastic-plastic properties. A fatigue life prediction model, evolved from an empirically derived formula based upon a modified Coffin-Manson fatigue theory, was then established. CCGA test results, obtained from various sources, combined with the derived solder strains were used to calibrate the proposed life prediction model. In the model calibration process, the 625- and 1657-pin CCGA test results, which were cycled between 20°C/90°C, 0°C/100°C, −55°C/110°C, or −55°C/125°C, were reasonably well correlated to the calculated values of solder strains. In addition, this calibrated model is remarkably simple compared to the model used in an evaluation by a finite element analysis. Therefore, this model could be used and is recommended to serve as an effective tool to make a preliminarily estimate at the CCGA solder joint thermal fatigue life. It is also recommended to 1) select more study cases with various solder joint configurations, package sizes, environmental profiles, etc. to further calibrate this life prediction model, 2) use this model to conduct parametric studies to identify critical factors impacting solder joint fatigue life and then seeking an optimum design, and 3) develop a similar life prediction model for lead-free solder materials.

Vibration Fatigue Test of Surface Mount Electronic Components

2003 ◽  
Author(s):  
T. E. Wong ◽  
H. S. Fenger
Keyword(s):  
Solder Joint ◽  
Random Vibration ◽  
Flip Chip ◽  
Prediction Models ◽  
Physical Analysis ◽  
Test Results ◽  
Printed Wiring Board ◽  
Joint Stress ◽  
Vibration Fatigue ◽  
Vibration Tests

The objectives of the present studies are to design and test representative commercial off-the-shelf plastic encapsulated microcircuits, including various types of ball grid array (BGA) components, chip scale package, flip chip, lead flat pack, and leadless capacitor, over military random vibration levels. The approach is to demonstrate the solder joint reliability performance of these components through the design of an electrical daisy-chain pattern printed wiring board (PWB) assembly test vehicle (TV), in which the design and manufacturing variables are included. The three variables, including BGA underfilled materials, solder pad sizes on PWB, and BGA rework, with each having either two or three levels of variation are used to address test criteria and to construct 14 different types of TV configurations. All TV configurations are then subjected to random vibration tests while continuously monitoring solder joint integrity. Based on the measured results, a destructive physical analysis is then conducted to further isolate the failure locations and determine the failure mechanisms of the solder joints. Test results indicate that the 352-pin tape BGA and 600-pin super BGA are more susceptible to failure than plastic BGAs under the same conditions, and that the use of underfilled materials appears to improve the life expectancy of all the components. The stiffer packages of tape BGA and super BGA, which have copper heat spreaders, may account for higher BGA solder joint stress/strain during random vibration tests. Test data also shows that only a limited number of electrical opening are observed. This indicates that the test modules are robust enough to survive the random vibration inputs. One possible reason is that the test modules are very stiff, whose 1st mode of natural frequency is about 550 Hz. Therefore, the curvature changes of the test modules are minimal, which resulted in smaller relative motion between the package and the PWB, and less solder joint stresses. All these test results are recommended to be used for calibrating BGA solder joint vibration fatigue life prediction models, which will be presented in other publications.

Design of Experiments in Ball Grid Array Thermal Fatigue Life Tests

2002 ◽  
Author(s):  
T. E. Wong ◽  
C. Y. Lau ◽  
L. A. Kachatorian ◽  
H. S. Fenger ◽  
I. C. Chen
Keyword(s):  
Fatigue Life ◽  
Thermal Fatigue ◽  
Solder Joints ◽  
Ball Grid Array ◽  
Temperature Cycling ◽  
Design Parameters ◽  
Physical Analysis ◽  
Printed Wiring Board ◽  
Thermal Fatigue Life ◽  
The Impact

The objective of the present study is to evaluate the impact of electronic packaging design/manufacturing process parameters on the thermal fatigue life of ball grid array (BGA) solder joints. The four selected parameters are BGA under-fill materials, conformal coating, solder pad sizes on printed wiring board, and BGA rework, with each having either two or three levels of variation. A test vehicle (TV), on which various sizes of BGA daisy-chained packages are soldered, is first designed and fabricated, and then subjected to temperature cycling (−55°C to +125°C) with continuous monitoring of solder joint integrity. The total of 15 experimental cases is used in the present study. Based on monitored results, a destructive physical analysis is conducted to further isolate the failure locations and determine the failure mechanisms of the solder joints. Test results indicate that the influence of these design parameters on fatigue life is dependent on the particular package, in some instances improving the fatigue life tenfold.

CBGA Solder Joint Thermal Fatigue Life Estimation by a Simple Method

2003 ◽  
Author(s):  
T. E. Wong ◽  
C. Y. Lau ◽  
H. S. Fenger
Keyword(s):  
Fatigue Life ◽  
Solder Joint ◽  
Prediction Model ◽  
Thermal Fatigue ◽  
Life Prediction ◽  
Test Results ◽  
Electronic Package ◽  
Eutectic Solder ◽  
Thermal Fatigue Life ◽  
Life Prediction Model

A simple analysis method was developed to determine the fatigue life of a ceramic ball grid array (CBGA) solder joint when exposed to thermal environments. The solder joint consists of a 90Pb/10Sn solder ball with eutectic solder on both top and bottom of the ball. Failure of the solder joint occurs at the eutectic solder. A closed-form solution with the equilibrium of displacements of electronic package assembly was first developed to calculate the solder joint strains during the temperature cycling. In the calculation, an iteration technique was used to obtain a convergent solution in the solder strains, and the elastic material properties were used for all the electronic package assembly components except for the solder materials, which used elastic-plastic properties. A fatigue life prediction model, evolved from an empirically derived formula based upon a modified Coffin-Manson fatigue theory, was then established. CBGA test results, obtained from Motorola, combined with the derived solder strains were used to calibrate the proposed life prediction model. In the model calibration process, the 255- and 304-pin CBGA test results, which were cycled between 0°C and 100°C or −40°C and 125°C, were reasonably well correlated to the calculated values of solder strains. In addition, this calibrated model is remarkably simple compared to the model used in an evaluation by finite element analysis. Therefore, this model could be used and is recommended to serve as an effective tool to preliminarily estimate the CBGA solder joint thermal fatigue life.

Application of Finite Element Method in Optimal Design of Flip-Chip Package

2011 ◽  
Vol 264-265 ◽  
pp. 1660-1665
Author(s):  
Yong Cheng Lin ◽  
Yu Chi Xia
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Solder Joint ◽  
Thermal Fatigue ◽  
Flip Chip ◽  
Solder Joints ◽  
Temperature Cycling ◽  
Lead Free ◽  
Lead Free Solder ◽  
Free Solder

More and more solder joints in circuit boards and electronic products are changing to lead free solder, placing an emphasis on lead free solder joint reliability. Solder joint fatigue failure is a serious reliability concern in area array technologies. In this study, the effects of substrate materials on the solder joint thermal fatigue life were investigated by finite element model. Accelerated temperature cycling loading was imposed to evaluate the reliability of solder joints. The thermal strain/stress in solder joints of flip chip assemblies with different substrates was compared, and the fatigue life of solder joints were evaluated by Darveaux’s crack initiation and growth model. The results show the mechanisms of substrate flexibility on improving solder joint thermal fatigue.

Solder Joint Reliability Analysis of WLCSP Based on Inelastic Analysis

2006 ◽  
Vol 306-308 ◽  
pp. 643-648 ◽  
Author(s):  
Chia Lung Chang ◽  
Tzu-Jen Lin ◽  
Kenny Huang
Keyword(s):  
Fatigue Life ◽  
Solder Joint ◽  
Shear Strain ◽  
Prediction Models ◽  
Inelastic Strain ◽  
Temperature Cycling ◽  
Cycling Test ◽  
Inelastic Analysis ◽  
Temperature Cycling Test ◽  
Total Shear

Nonlinear finite element analysis is performed to evaluate the reliability of the solder joint of wafer level chip scale package (WLCSP) under accelerated temperature cycling test. The solder joint is subjected to the inelastic strain that is generated during the temperature cycling test due to the thermal expansion mismatch between the various materials of the package and PCB (printed circuit board). The equivalent stress, equivalent inelastic strain, total shear strain, and hysteresis loop of the solder joint are determined in the simulation. The equivalent inelastic strain and total shear strain range of the joint are obtained as damage criterion to predict the solder fatigue. Both Coffin-Manson and Modified Coffin-Manson fatigue life prediction models are used to estimate the thermal fatigue life of WLCSP solder joints under temperature cycling test. Also, the effects of the material properties of the stress buffer layer (SBL) on the fatigue life of the solder joint are discussed.

Precision Evaluation for Thermal Fatigue Life of Power Module Using Coupled Electrical-Thermal-Structural Analysis

2011 ◽  
Author(s):  
Tomohiro Takahashi ◽  
Qiang Yu ◽  
Masahiro Kobayashi
Keyword(s):  
Fatigue Life ◽  
Temperature Distribution ◽  
Solder Joint ◽  
Thermal Fatigue ◽  
Thermal Structure ◽  
Inelastic Strain ◽  
Power Module ◽  
Thermal Fatigue Life ◽  
Power Cycling ◽  
Precision Evaluation

For power module, the reliability evaluation of thermal fatigue life by power cycling has been prioritized as an important concern. Since in power cycling produces there exists non-uniform temperature distribution in the power module, coupled thermal-structure analysis is required to evaluate thermal fatigue mechanism. The thermal expansion difference between a Si chip and a substrate causes thermal fatigue. In this study, thermal fatigue life of solder joints on power module was evaluated. The finite element method (FEM) was used to evaluate temperature distribution induced by joule heating. Higher temperature appears below the Al wire because the electric current flows through the bonding Al wire. Coupled thermal-structure analysis is also required to evaluate the inelastic strain distribution. The damage of each part of solder joint can be calculated from equivalent inelastic strain range and crack propagation was simulated by deleting damaged elements step by step. The initial cracks were caused below the bonding Al wire and propagated concentrically under power cycling. There is the difference from environmental thermal cycling where the crack initiated at the edge of solder layer. In addition, in order to accurately evaluate the thermal fatigue life, the factors affecting the thermal fatigue life of solder joint where verified using coupled electrical-thermal-structural analysis. Then, the relation between the thermal fatigue life of solder joint and each factor is clarified. The precision evaluation for the thermal fatigue life of power module is improved.

scholarly journals Fatigue Life Prediction of Rolling Bearings Based on Modified SWT Mean Stress Correction

2020 ◽  
Author(s):  
Aodi Yu ◽  
Hong-Zhong Huang ◽  
Yan-Feng Li ◽  
He Li ◽  
Ying Zeng
Keyword(s):  
Fatigue Life ◽  
Life Prediction ◽  
Stress Ratio ◽  
Prediction Models ◽  
Great Influence ◽  
Sensitivity Coefficient ◽  
Model Verification ◽  
Mean Stress ◽  
Test Results ◽  
Rolling Bearings

Abstract Mean stress has a great influence on fatigue life, commonly used stress-based life prediction models can only fit the test results of fatigue life under specific stress ratio or mean stress but cannot describe the effect of stress ratio or mean stress on fatigue life. Smith, Watson and Topper (SWT) proposed a simple mean stress correction criterion. However, the SWT model regards the sensitivity coefficient of all materials to mean stress as 0.5, which will lead to inaccurate predictions for materials with a sensitivity coefficient not equal to 0.5. In this paper, considering the sensitivity of different materials to mean stresses, compensation factor is introduced to modify the SWT model, and several sets of experimental data are used for model verification. Then, the proposed model is applied to fatigue life predictions of rolling bearings, and the results of proposed method are compared with test results to verify its accuracy.

Thermal Fatigue Prediction for Leadless Solder Joint of TFBGA

2006 ◽  
Author(s):  
Chia-Lung Chang ◽  
Tzu-Jen Lin ◽  
Chih-Hao Lai
Keyword(s):  
Energy Density ◽  
Solder Joint ◽  
Creep Strain ◽  
Thermal Fatigue ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Creep Property ◽  
Inelastic Strain ◽  
Temperature Cycling ◽  
Element Analysis

Nonlinear finite element analysis was performed to predict the thermal fatigue for leadless solder joint of TFBGA Package under accelerated TCT (Temperature Cycling Test). The solder joint was subjected to the inelastic strain that was generated during TCT due to the thermal expansion mismatch between the package and PCB. The solder was modeled with elastic-plastic-creep property to simulate the inelastic deformation under TCT. The creep strain rate of solder was described by double power law. The furthest solder away from the package center induced the highest strain during TCT was considered as the critical solder ball to be most likely damaged. The effects of solder meshing on the damage parameters of inelastic strain range, accumulated creep strain and creep strain energy density were compared to assure the accuracy of the simulation. The life prediction equation based on the accumulated creep strain and creep strain energy density proposed by Syed was used to predict the thermal fatigue life in this study. The agreement between the prediction life and experimental mean life is within 25 per cent. The effect of die thickness and material properties of substrate on the life of solder was also discussed.

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