J-Lead Solder Joint Thermal Fatigue Life Model

1999 ◽  
Vol 121 (3) ◽  
pp. 186-190 ◽  
Author(s):  
T. E. Wong ◽  
L. A. Kachatorian ◽  
H. M. Cohen

A thermal fatigue life prediction model of J-lead solder joint assembly has been developed. This model is evolved from an empirically derived formula based on modified Manson-Coffin fatigue life Prediction theory. To estimate solder joint fatigue life, nonlinear finite element analysis (FEA) was conducted using the ABAQUS™ computer code. The analysis results show that cracks are initiated and propagated from both the heel and the toe of the solder joint toward the center portion of the joint. This condition results in the solder joint fatigue life degradation and is included in the model development. The fatigue life prediction model is then calibrated to life cycling test results, which were provided by Jet Propulsion Laboratory (JPL/NASA). The developed life prediction model, combined with the nonelastic strains derived from FEA and Miner’s cumulative damage law, was used to predict the cumulative damage index of the solder joint under NASA’s thermal cycling environment (between −55°C and 100°C). The analysis results indicate that this solder joint has a 50 percent failure probability when the solder joint is exposed up to 5206 thermal cycles. To shorten the test time, a modified thermal cycling profile was proposed. This profile is the same as the NASA thermal cycling environment except using the high end of the dwell temperature at 125°C. The analysis results show that a 50 percent failure probability of the solder joint would occur after the solder joint is exposed to 3500 cycles of the NASA thermal environment and followed by 1063 cycles of the modified thermal profile. In conclusion, the developed life prediction model is recommended to serve as an effective tool to integrate the process of design selection, quality inspection, and qualification testing in a concurrent engineering process. It is also recommended to conduct a micro-section in the solder joint to verify the solder crack paths and further validate the life prediction model. When additional thermal cycles have been added into the test specimens, recalibrating this model by test is also recommended.

Author(s):  
T. E. Wong ◽  
C. Chu

A thermal fatigue life prediction model of a ceramic column grid array (CCGA) solder joint assembly has been developed when the 90Pb/10Sn solder columns of the CCGA package are soldered onto the printed circuit board with either tin-lead or lead-free solder paste. This model was evolved from an empirically derived formula by correlating the solder nonelastic strain energy density increment to the fatigue life test data. To develop the solder joint fatigue life prediction model, a nonlinear finite element analysis (FEA) was conducted using the ABAQUS computer code. A thermal fatigue life prediction model was then established. The test results, obtained from various sources in which tin-lead and lead-free solder pastes on PCB were used, combined with the FEA derived nonelastic strain energy density per temperature cycle, ΔW, were used to calibrate the proposed life prediction model. In the analysis, 3-D finite element global- and sub-modeling techniques were used to determine the ΔW of the CCGA solder joints when subjected to temperature cycling. The analysis results show that: 1) solder joint would typically fail across solder column instead of along solder pad interfaces; and 2) higher nonelastic strain energy densities of solder occur at the solder columns at the package corners and these solder joints would fail first. These analysis predictions are consistent with the test observations. 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 predicted values of ΔW. Therefore, the developed life prediction model could be used and is recommended to serve as an effective tool to determine the integrity of the CCGA solder joints during temperature cycling. In addition, the following future work is recommended: 1) selecting more study cases with various solder joint configurations, package sizes, environmental profiles, etc. to further calibrate this life prediction model; 2) using this model to conduct parametric studies to identify critical factors impacting solder joint fatigue life and then seek an optimum design; and 3) developing a simplified method instead of the FEA approach to make preliminary thermal fatigue life estimates of the CCGA solder joints.


Author(s):  
T. E. Wong ◽  
C. Chu

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.


Author(s):  
T. E. Wong ◽  
C. Y. Lau ◽  
H. S. Fenger

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.


2000 ◽  
Author(s):  
T. E. Wong ◽  
F. W. Palmieri ◽  
L. A. Kachatorian

Abstract A newly developed methodology is used to support test validation of ball grid array (BGA) solder joint vibration fatigue life prediction model. This model is evolved from an empirical formula of universal slopes, which is derived from high-cycle fatigue test data using a curve fitting technique over 29 different materials of metals. To develop the BGA solder joint vibration fatigue life prediction model, a test vehicles (TV), on which various sizes of BGA daisy-chained packages are soldered, is first designed, fabricated and subjected to random vibration tests with continuously monitoring the solder joint integrity. Based on the measurement results, a destructive physical analysis is then conducted to further verify the failure locations and crack paths of the solder joints. Next, a method to determine the stresses/strains of BGA solder joints resulting from exposure of the TV to random vibration environments is developed. In this method, a 3-D modeling technique is used to simulate the vibration responses of the BGA packages. Linear static and dynamic finite element analyses with MSC/NASTRAN™ computer code, combined with a volume-weighted average technique, are conducted to calculate the effective strains of the solder joints. In the calculation process, several in-house developed Fortran programs, in conjunction with the outputs obtained from MSC/NASTRAN™ static and frequency response analyses, are used to perform the required computations. Finally, a vibration fatigue life model is established with two unknown parameters, which can be determined by correlating the derived solder effective strains to the test data. This test-calibrated model is then recommended to serve as an effective tool to determine the integrity of the BGA solder joints during vibration. Selecting more study cases with various package sizes, solder ball configurations, vibration profiles to further calibrate this model is also recommended. An example of a 313-pin plastic and 304-pin ceramic BGAs is illustrated in the present study.


2012 ◽  
Vol 577 ◽  
pp. 127-131 ◽  
Author(s):  
Peng Wang ◽  
Tie Yan ◽  
Xue Liang Bi ◽  
Shi Hui Sun

Fatigue damage in the rotating drill pipe in the horizontal well of mining engineering is usually resulted from cyclic bending stresses caused by the rotation of the pipe especially when it is passing through curved sections or horizontal sections. This paper studies fatigue life prediction method of rotating drill pipe which is considering initial crack in horizontal well of mining engineering. Forman fatigue life prediction model which considering stress ratio is used to predict drill string fatigue life and the corresponding software has been written. The program can be used to calculate the stress of down hole assembly, can predict stress and alternating load in the process of rotating-on bottom. Therefore, establishing buckling string fatigue life prediction model with cracks can be a good reference to both operation and monitor of the drill pipe for mining engineering.


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