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.

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.

Thermal Fatigue Life Prediction Model of CCGA Tin-Lead and Lead-Free Interconnects

2006 ◽  
Author(s):  
T. E. Wong ◽  
C. Chu
Keyword(s):  
Fatigue Life ◽  
Solder Joint ◽  
Prediction Model ◽  
Thermal Fatigue ◽  
Strain Energy ◽  
Life Prediction ◽  
Solder Joints ◽  
Fatigue Life Prediction ◽  
Thermal Fatigue Life ◽  
Life Prediction Model

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.

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
Keyword(s):  
Fatigue Life ◽  
Solder Joint ◽  
Prediction Model ◽  
Thermal Cycling ◽  
Failure Probability ◽  
Life Prediction ◽  
Fatigue Life Prediction ◽  
Thermal Fatigue Life ◽  
Solder Joint Fatigue ◽  
Life Prediction Model

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.

Wire Flexure Fatigue Model for Asymmetric Bond Height

2003 ◽  
Author(s):  
Karumbu Nathan Meyyappan ◽  
Peter Hansen ◽  
Patrick McCluskey
Keyword(s):  
Prediction Model ◽  
Life Prediction ◽  
Damage Model ◽  
Cyclic Strain ◽  
Design Guidelines ◽  
Temperature Cycling ◽  
Transformation Model ◽  
Test Results ◽  
The Wire ◽  
Life Prediction Model

This paper presents the first physics-of-failure based life prediction model for flexural failure of wires ultrasonically wedge bonded to pads at different heights. The life prediction model consists of a load transformation model and a damage model. The load transformation model determines the cyclic strain at the heel of the wire during temperature cycling. This cyclic strain is created by a change in wire curvature at the heel of the wire resulting from expansion of the wire and displacement of the frame. The damage model calculates the life based on the strain cycle magnitude and the elastic-plastic fatigue response of the wire. The model supports virtual qualification of power modules where wire flexural fatigue is a dominant failure mechanism. The model has been validated using temperature cycling test results, and can be used to derive design guidelines and establish a relation between accelerated test results and field life.

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.

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