Effect of solder joint geometry on the predicted fatigue life of BGA solder joints

2002 ◽  
Author(s):  
I.R. Holub ◽  
J.M. Pitarresi ◽  
T.J. Singler
Keyword(s):  
Fatigue Life ◽  
Solder Joint ◽  
Solder Joints ◽  
Joint Geometry

scholarly journals Prediction of mechanical properties and fatigue life of nano silver paste in chip interconnection

2020 ◽  
Author(s):  
Hui YANG ◽  
Jihui Wu
Keyword(s):  
Fatigue Life ◽  
Solder Joint ◽  
Thermal Cycling ◽  
Solder Joints ◽  
Stress And Strain ◽  
Nano Silver ◽  
Finite Element Software ◽  
Flip Chips ◽  
Empirical Correction ◽  
Prediction Of Mechanical Properties

Abstract The simulation of nano-silver solder joints in flip-chips is performed by the finite element software ANSYS, and the stress-strain distribution results of the solder joints are displayed. In this simulation, the solder joints use Anand viscoplastic constitutive model, which can reasonably simulate the stress and strain of solder joints under thermal cycling load. At the same time this model has been embedded in ANSYS software, so it is more convenient to use. The final simulation results show that the areas where the maximum stresses and strains occur at the solder joints are mostly distributed in the contact areas between the solder joints and the copper pillars and at the solder joints. During the entire thermal cycling load process, the area where the maximum change in stress and strain occurs is always at the solder joint, and when the temperature changes, the temperature at the solder joint changes significantly. Based on comprehensive analysis, the relevant empirical correction calculation equation is used to calculate and predict the thermal fatigue life of nano-silver solder joints. The analysis results provide a reference for the application of nano-silver solder in the electronic packaging industry.

Effect of Micro Structure on Fatigue Characteristics of Lead Free Solder Joints

2011 ◽  
Author(s):  
Takahiro Akutsu ◽  
Qiang Yu
Keyword(s):  
Grain Size ◽  
Fatigue Crack ◽  
Fatigue Life ◽  
Solder Joint ◽  
Crack Propagation ◽  
Solder Joints ◽  
Lead Free ◽  
Lead Free Solder ◽  
Micro Structure ◽  
Free Solder

This paper presents the influence of the micro structure on the crack propagation in lead free solder joint. The author’s group have studied the Manson-Coffin’s law for lead free solder joint by using the isothermal fatigue test and FEM analytical approaches to establish the practicable evaluation of thermal fatigue life of solder joints, for example, for the Sn-Cu-Ni solder, because this solder is attracted from the aspect of the decrease of solder leach in the flow process and material cost. However, even if the same loading is given to the solder joints of BGA test piece, there was a large dispersion in the fatigue life. Even though the effect of the shape difference has been considered, the range of the dispersion could not been explained sufficiently. In the study, the fatigue crack propagation modes in the solder joints were investigated, and an internal fatigue crack mode and an interfacial fatigue crack mode were confirmed. And the tendency of a shorter on fatigue life in the interfacial fatigue mode was confirmed. To clarify the mechanism of these fatigue crack modes, the crystal grain size in the solder joints was investigated before the fatigue test and also after the test. Furthermore, the verification of the mechanism using FEM models considering the crystal grain size was carried out. First of all, each element in FEM models matching to the average crystal grain size was made. Second, the inelastic strain ranges in each FEM models were studied. As a result, it was shown that the influence of the crude density of the crystal grain to the fatigue crack progress can be evaluated. In addition, the micro structure of the solder joint of large-scale electronic devices is observed, and FEM model was made based on the observation result. As a result, it was shown that the influence of the directionality with the crystal grain to the fatigue crack progress can be evaluated.

Thermomechanical Analysis of Solder Joints Under Thermal and Vibrational Loading

2001 ◽  
Vol 124 (1) ◽  
pp. 60-66 ◽  
Author(s):  
Cemal Basaran ◽  
Rumpa Chandaroy
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Solder Joint ◽  
Constitutive Model ◽  
Solder Joints ◽  
Cycle Fatigue ◽  
Simultaneous Application ◽  
Short Cycle ◽  
Finite Element Procedure ◽  
Life Predictions

Due to the coefficient of thermal expansion (CTE) mismatch between the bonded layers, the solder joint experiences cycling shear strain, which leads to short cycle fatigue. When semiconductor devices are used in a vibrating environment, additional strains shorten the fatigue life of a solder joint. Reliability of these joints in new packages is determined by laboratory tests. In order to use the FEM to replace these expensive reliability tests a unified constitutive model for Pb40/Sn60 solder joints has been developed and implemented in a thermo-viscoplastic-dynamic finite element procedure. The model incorporates thermal-elastic-viscoplastic and damage capabilities in a unified manner. The constitutive model has been verified extensively against laboratory test data. The finite element procedure was used for coupled thermo-viscoplastic-dynamic analyses for fatigue life predictions. The results indicate that using Miner’s rule to calculate accumulative damage by means of two separate analyses, namely dynamic and thermo-mechanical, significantly underestimates the accumulative total damage. It is also shown that a simultaneous application of thermal and dynamic loads significantly shortens the fatigue life of the solder joint. In the microelectronic packaging industry it is common practice to ignore the contribution of vibrations to short cycle fatigue life predictions. The results of this study indicate that damage induced in the solder joints by vibrations have to be included in fatigue life predictions to accurately estimate their reliability.

Deterministic and Statistical Reliability of Surface Mount Components

2002 ◽  
Author(s):  
Zhengfang Qian ◽  
Xiaohua Wu ◽  
Joe Tomase
Keyword(s):  
Fatigue Life ◽  
Crack Initiation ◽  
Solder Joint ◽  
Crack Propagation ◽  
Temperature Profile ◽  
Failure Rate ◽  
Inelastic Strain ◽  
Reliability Prediction ◽  
Joint Geometry ◽  
Statistical Reliability

This paper is to investigate both deterministic and statistical aspects of thermal reliability of solder joints of surface mount leadless components (SMLCs). The emphasis is on bridging deterministic with statistical reliability prediction. A reliable methodology has been established to predict the failure rate at accelerated life tests (ALTs) and field failed rate in terms of key statistical parameters of design, environmental condition, and material selection due to the uncertainty from the component manufacturing/assembly, temperature profile of ALTs and field environmental conditions, and material property. Analytical equations and solutions of inelastic strain range and fatigue life for simplified joint geometry have been developed from deterministic approach. They are furthermore utilized to obtain the failure functions of thermal fatigue caused by both crack initiation and crack propagation from multivariable distributions. First Order Reliability Model (FORM) has been extended by combining Taylor series in technique with central limit theorem (CLT). An important outcome is that the statistical fatigue life is a lognormal distribution in which its parameters can be analytically evaluated by the approximate method with satisfactory accuracy for small COVs (COV=mean/deviation) of random variables (RVs). Specifically, SMLCs have been investigated on inelastic strain distribution, fatigue life distribution, failure and reliability functions, and failure rate prediction based on the statistical distributions of the solder joint height, solder paste size, temperature profile, and the experimental property of the eutectic solder alloy. Moreover, the component failure under two failure modes, i.e., both crack initiation and crack propagation, has been performed to illustrate the significance of failure criteria selection and address the data collection in field. Additionally, the simulation of realistic solder joint geometry and damage-based failure processes will be also presented. The developed methodology can be directly used for the board-level reliability prediction of advanced electronic packages such as BGAs, CSPs, QFPs, and Flip-chips.

Solder Joint Reliability — Design Implications From Finite Element Modeling and Experimental Testing

1990 ◽  
Vol 112 (2) ◽  
pp. 135-146 ◽  
Author(s):  
H. K. Charles ◽  
G. V. Clatterbaugh
Keyword(s):  
Fracture Toughness ◽  
Finite Element ◽  
Fatigue Life ◽  
Solder Joint ◽  
Solder Joints ◽  
Experimental Testing ◽  
Sectional Area ◽  
Stress Concentrations ◽  
Cross Sectional ◽  
Power Cycling

An extensive finite element modeling and experimental testing program has been carried out to determine the most optimum design parameters for solder joints in surface mount applications. Although the analysis and testing (power cycling and thermal cycling) has been carried out for a variety of package styles, particular attention will be paid to the result for leadless ceramic chip carriers. This package is particularly useful in certain high performance military and commercial applications. Analysis and experimentation indicate that increased fatigue life under power cycling can be attained by fabricating solder joints with large fillets and low standoff heights. The large fillet geometry significantly reduces harmful stress concentrations while increasing the net cross-sectional area within the joint. Both factors tend to improve the fracture toughness of the joint. The temperature and frequency dependencies of solder joint fatigue life under power cycling testing is discussed. The observed frequency dependence can be minimized by eliminating harmful tensile strain components thus reducing harmful stress relaxation and tensile induced oxygen embrittlement of grain boundaries. Temperature cycling studies indicate joints with slightly higher standoffs and low fillet angles are more resistant to cyclic fatigue than pillar type joints which tend to focus shear strains at the interfaces. Solder joints can be tapered to improve overall reliability but, in most cases, tapering will provide only a small increase in fracture toughness of the joint through the elimination of stress concentrations. Additional fatigue life increases can be obtained only through an enlargement of the joint cross-sectional area. Aspects of the above results will be presented in detail along with design guidelines for creating high reliability solder joints for various application scenarios.

Parameterized Modeling of Thermomechanical Reliability for CSP Assemblies

2003 ◽  
Vol 125 (4) ◽  
pp. 498-505 ◽  
Author(s):  
Bart Vandevelde ◽  
Eric Beyne ◽  
Kouchi (G.Q.) Zhang ◽  
Jo Caers ◽  
Dirk Vandepitte ◽  
...  
Keyword(s):  
Finite Element ◽  
Solder Joint ◽  
Empirical Model ◽  
Prediction Models ◽  
Solder Joints ◽  
Coefficient Of Thermal Expansion ◽  
Solder Joint Reliability ◽  
Joint Geometry ◽  
Joint Reliability ◽  
Area Array

Finite element modeling is widely used for estimating the solder joint reliability of electronic packages. In this study, the electronic package is a CSP mounted on a printed circuit board (PCB) using an area array of solder joints varying from 5×4 up to 7×7. An empirical model for estimating the reliability of CSP solder joints is derived by correlating the simulated strains to thermal cycling results for 20 different sample configurations. This empirical model translates the inelastic strains calculated by nonlinear three-dimensional (3D) finite element simulations into a reliability estimation (N50% or N100 ppm). By comparing with the results of reliability tests, it can be concluded that this model is accurate and consistent for analyzing the effect of solder joint geometry. Afterwards, parameter sensitivity analysis was conducted by integrating a design of experiment (DOE) analysis with the reliable solder fatigue prediction models, following the method of simulation-based optimization. Several parameters are analyzed: the PCB parameters (elastic modulus, coefficient of thermal expansion, thickness), the chip dimensions (area array configuration), and the parameters defining the solder joint geometry (substrate and chip pad diameter, solder volume). The first study analyzes how the solder joint geometry influences the CSP reliability. A second study is a tolerance analysis for six parameters. These parameters can have a tolerance (=accuracy) of their nominal value, and it is shown that these small tolerances can have a significant influence on the solder joint reliability.

A Damage Evolution Model for Thermal Fatigue Analysis of Solder Joints

1999 ◽  
Vol 122 (3) ◽  
pp. 200-206 ◽  
Author(s):  
Xiaowu Zhang ◽  
S-W. Ricky Lee ◽  
Yi-Hsin Pao
Keyword(s):  
Fatigue Life ◽  
Solder Joint ◽  
Thermal Fatigue ◽  
Material Properties ◽  
Damage Evolution ◽  
Solder Joints ◽  
Evolution Model ◽  
Model Verification ◽  
Thermal Fatigue Life ◽  
Double Beam

Thermal fatigue of solder joints is critical to the performance and reliability of electronic components. It is well known that the fatigue life of solder joints is rather difficult to be estimated because of the complicated material behaviors and solder joint geometry. Conventional life prediction methods such as Coffin-Manson equation or its modifications usually over-estimate the thermal fatigue life. The main reason for this phenomenon is that the material properties are assumed constant during thermal cycling. In this paper, a damage evolution model is introduced for predicting the thermal fatigue life of solder joints. This method not only considers the degradation of material properties in the solder, but also saves substantial computational effort. In the present study, a damage function is determined by the hysteresis loops of creep shear stress-strain of solder joints in a double-beam specimen. The proposed model is then applied to investigate the solder joint reliability of a 272 PBGA package and a bottom-leaded plastic (BLP) package for model verification. The results from the present analysis seem to be encouraging. [S1043-7398(00)01003-3]

scholarly journals Prediction of mechanical properties and fatigue life of nano silver paste in chip interconnection

2020 ◽  
Author(s):  
Hui Yang ◽  
Jihui Wu
Keyword(s):  
Fatigue Life ◽  
Solder Joint ◽  
Thermal Cycling ◽  
Solder Joints ◽  
Stress And Strain ◽  
Nano Silver ◽  
Finite Element Software ◽  
Flip Chips ◽  
Empirical Correction ◽  
Prediction Of Mechanical Properties

Abstract The simulation of nano-silver solder joints in flip-chips is performed by the finite element software ANSYS, and the stress-strain distribution results of the solder joints are displayed. In this simulation, the solder joints use Anand viscoplastic constitutive model, which can reasonably simulate the stress and strain of solder joints under thermal cycling load. At the same time this model has been embedded in ANSYS software, so it is more convenient to use. The final simulation results show that the areas where the maximum stresses and strains occur at the solder joints are mostly distributed in the contact areas between the solder joints and the copper pillars and at the solder joints. During the entire thermal cycling load process, the area where the maximum change in stress and strain occurs is always at the solder joint, and when the temperature changes, the temperature at the solder joint changes significantly. Based on comprehensive analysis, the relevant empirical correction calculation equation is used to calculate and predict the thermal fatigue life of nano-silver solder joints. The analysis results provide a reference for the application of nano-silver solder in the electronic packaging industry.

Fatigue Properties and Microstructure of SnAgCu Bi-Based Solder Joint

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Minghong Jian ◽  
Sinan Su ◽  
Sa'd Hamasha ◽  
Mohammad M. Hamasha ◽  
Atif Alkhazali
Keyword(s):  
Fatigue Life ◽  
Plastic Strain ◽  
Solder Joint ◽  
Solder Joints ◽  
Hysteresis Loops ◽  
Strain Range ◽  
Fatigue Performance ◽  
Fatigue Properties ◽  
Solder Alloys ◽  
Plastic Strain Range

Abstract The reliability of solder joints plays a critical role in electronic assemblies. SnAgCu solder alloys with doped elements such as Bi and Sb is one of the candidates for high reliability applications. However, the mechanical and fatigue properties of the actual solder joint structure have not been studied for these new alloys. In this paper, a cyclic fatigue test was conducted on individual real solder joints of different alloys, including SnAgCu, SnCu–Bi, SnAgCu–Bi, and SnAgCu–BiSb. The fatigue property of those solder joints was analyzed based on the characteristic fatigue life and stress–strain, hysteresis, loops. The results show that solder joints with both Ag and Bi content have a better fatigue resistance than the solder joints with Ag or Bi content only. The results of SnAgCu and SnCu–Bi solder alloys show similar fatigue performance. Also, the fatigue performance of SnAgCu–Bi is close to SnAgCu–BiSb in the accelerated test. But the SnAgCu–Bi alloy is estimated to have a longer characteristic life under low-stress amplitude cycling. The microstructure analysis shows a bismuth-rich phase formed around the Ag3Sn precipitates. Adding bismuth in the solder alloy can significantly improve the fatigue properties through solid solution hardenings. On another hand, the plastic strain range and work dissipation were measured from the hysteresis loops for all tests. The Morrow Energy and the Coffin–Manson models were developed from the fitted data to predict the fatigue life as a function of work dissipation and plastic strain range.

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.

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