Enhancing solder joint fatigue life for ball grid array packages

Author(s):  
Zhou Wei ◽  
Lim Beng Kuan
Author(s):  
Krishna Tunga ◽  
James Pyland ◽  
Raghuram V. Pucha ◽  
Suresh K. Sitaraman

Various constitutive and fatigue-life predictive models for lead-tin solders in SBGA (Super Ball Grid Array) packages are studied and compared with the results from experimental data. Two solder compositions, 62Sn/36Pb/2Ag and 63Sn/37Pb are studied in this work. The fatigue life of 62Sn/36Pb/2Ag solder is studied using different constitutive models that take into consideration both the time-independent and time-dependent behavior of the solder. The fatigue life of 62Sn/36Pb/2Ag solder is predicted using an energy-based predictive model and compared with the experimental data. The choice of various predictive models on the solder joint life is studied using 63Sn/37Pb solder. Various predictive models, available in the literature, for eutectic and near eutectic solder compositions are studied to predict the fatigue life. Guidelines are provided for selecting constitutive and predictive models with appropriate damage metrics.


2001 ◽  
Vol 24 (4) ◽  
pp. 439-451 ◽  
Author(s):  
Hsien‐Chie Cheng ◽  
Kuo‐Ning Chiang ◽  
Chao‐Kuang Chen ◽  
Ji‐Cheng Lin

Author(s):  
Wei Wang ◽  
Tung Nguyen

Flip Chip Ball Grid Array packages (FCBGA) have been widely used in microelectronic industry in integrated circuit (IC) packages. Due to the intrinsic mismatch of the coefficient of thermal expansion (CTE) between silicon chip and Printed Circuit Board (PCB) material, solder joint fatigue failure due to thermal cycling becomes the most important concern for this technology. Underfill materials have been widely used as a solution to improving solder joint fatigue life. It is of importance to understand the effect of underfill material properties on the solder joint fatigue life. In this study, finite element method (FEM) was employed to study the effect of underfill materials on solder joint low cycle fatigue life in thermal cycling. ANSYS code was used to calculate the inelastic energy density generated in temperature cycling. The viscoplastic model was used for the solder to consider the inelastic and time dependent behavior under thermal cycling. By using the FEM model, the underfill material properties, the Young’s modulus and CTE were examined to study their effects on the solder joint fatigue life. It was found that the improvement of solder fatigue life could be achieved only when the CTE was low. This improvement could be strengthened by large Young’s modulus to increase the solder strength. In contrast, a large CTE underfill material could deepen the solder joint fatigue damage. This worsening effect became more significant as the Young’s modulus became larger. This study could serve as a foundation for understanding the mechanism of solder joint fatigue in the presence of underfill materials and provide guidance to choose appropriate underfill materials to improve BGA solder joint thermal fatigue in temperature cycling.


2016 ◽  
Vol 2016 (1) ◽  
pp. 000106-000110
Author(s):  
Jia-Shen Lan ◽  
Stuwart Fan ◽  
Louie Huang ◽  
Mei-Ling Wu

Abstract In this paper, the solder joint failure and the solder joint fatigue life in the Thin-profile Fine-pitch Ball Grid Array (TFBGA) Package was investigated by performing the drop test, and implementing a simulation model. Owing to the need to meet the increasing demands for functionality, microelectronic package reliability can be compromised and has become the key issue when executing drop tests. During impact in drop test, the deformation of PCB due to bending and mechanical shocks can cause solder joint crack. While this is a well-known issue, observing the solder joint responses during the test execution can be a challenge. Therefore, in this work, a simulation model approach has been developed to investigate the stress and strain of the solder joint during the drop test. In this research, the JEDEC Condition B drop test was simulated, characterized by 1500G peak acceleration and 0.5 ms duration. The drop test simulation model was successful in predicting the solder joint fatigue life with different solder joint materials, such as SAC105 and SAC1205N, while also facilitating result comparison to identify the most optimal structure.


1997 ◽  
Vol 119 (3) ◽  
pp. 171-176 ◽  
Author(s):  
T. E. Wong ◽  
L. A. Kachatorian ◽  
B. D. Tierney

A Taguchi design of experiment approach was applied to thermostructural analyses of a gull-wing solder joint assembly. This approach uses a minimum number of finite element analyses to evaluate the impact of solder joint assembly parameters on fatigue life of the assembly. To avoid costly complex modeling efforts for each parametric case study, a commercially available program, MSC/PATRAN’s PATRAN Command Language, was used to automatically create finite element models of a two-dimensional gull-wing solder joint assembly based on nine parameters. Modeling time was dramatically reduced from days to a few minutes for each detailed lead/solder model. Two sets of parametric studies were conducted to evaluate the impact of variation of the six parameters. The analysis results indicate that lead ankle radius is the most critical parameter affecting solder joint total fatigue life, and lead and minimum solder thicknesses are the next most critical ones. Therefore, to effectively improve the solder joint fatigue life margin, it is recommended to: (1) increase the minimum solder thickness; (2) use thinner lead; and (3) use a larger lead ankle radius, even though this may require reducing lead shin length. By implementing only the last recommendation to modify the current solder joint assembly, the fatigue life margin in this design could, in general, be improved by 27 percent or more.


Author(s):  
Pedro E. Ribeiro ◽  
Delfim F. Soares ◽  
Maria F. Cerqueira ◽  
Senhorinha F. Teixeira ◽  
Daniel A. Barros ◽  
...  

A common failure mode of electronic PCB’s is the appearance of cold solder joints between the component and PCB, during product life. This phenomenon is related to solder joint fatigue and is attributed mainly to the mismatch of the coefficients of thermal expansion (CTE) of component-solder-PCB assembly. Although some experiments show that newer lead-free tin-silver-copper (Sn-Ag-Cu, or SAC) solders perform better than the older SnPb ones, with today’s solder joint thickness decreasing and increasing working temperatures, among others, the stresses and strains due to temperature changes are growing, leading to limited fatigue life of the products. As fatigue life decreases with increasing plastic strain, creep occurrence should have significant impact, especially during thermal cycles. In order to improve mechanical properties, but also as an attempt to reduce maximum reflow cycle temperatures due to component damage and production costs, various SAC solder alloying additives are being considered to use in industrial production facilities. Solder paste producers are proposing new products based on new solder paste formulations, but the real life effects on thermo-mechanical performance aren’t well known at the moment. In this paper a dynamic mechanical analyser (DMA) is used to study the influence of Bismuth (Bi) addition, up to 5 wt %, on SAC405 solder paste, in terms of creep behaviour. Creep tests were made on three-point-bending configuration, isothermally at 30 °C, 50 °C and 75 °C, and three different stresses of 3, 5 and 9 MPa. The results shown not only a significant Bi concentration influence on creep behaviour but also a noticeable temperature dependence.


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