Influence of Surface Mount Lead End Geometry on Fatigue Life

1994 ◽  
Vol 116 (2) ◽  
pp. 157-160 ◽  
Author(s):  
Vineet K. Gupta ◽  
Donald B. Barker
Keyword(s):  
Fatigue Life ◽  
Solder Joint ◽  
Thermal Fatigue ◽  
Coefficient Of Thermal Expansion ◽  
Printed Wiring Board ◽  
Surface Mount ◽  
Compliant Surface ◽  
Board Surface ◽  
Cte Mismatch ◽  
Wiring Board

The local coefficient of thermal expansion (CTE) mismatch between compliant surface mount component leads and the solder that is used to attach the components to a printed wiring board can dramatically influence the thermal fatigue life of the solder joint. To quantify the contribution of the local CTE mismatch to the overall thermal fatigue damage of the solder joint, a finite element thermal fatigue simulation using an energy partitioning technique is used to compare four different lead end shapes. The four lead configurations considered are J-lead, and three gullwings leads; one with the foot parallel to the board surface, one with the foot sloped slightly downward towards the board, and one with the foot sloped slightly upward. The dimensions of the leads are purposely chosen so that the in-plane compliance is equal for the different lead shapes, only the shape of the lead end varied. Comparisons are first made with equal solder joint heights and then the solder height of the gull-wing lead is varied between 0.05 to 0.23 mm (2 to 9 mils). The influence of the solder wetting angle is also investigated.

Fatigue Analysis of a Planarpak™ Surface Mount Component

1991 ◽  
Vol 113 (2) ◽  
pp. 194-199 ◽  
Author(s):  
I. Sharif ◽  
D. B. Barker ◽  
A. Dasgupta ◽  
M. G. Pecht
Keyword(s):  
Fatigue Life ◽  
Thermal Stresses ◽  
Three Dimensional ◽  
Printed Wiring Board ◽  
Surface Mount ◽  
Dimensional Finite Element ◽  
Life Analysis ◽  
Fatigue Life Analysis ◽  
Wiring Board ◽  
Three Dimensional Finite Element

This paper discusses the thermo-mechanical fatigue life analysis of an analog Avantek Planarpak™ surface mount device where the entire base of the component is soldered directly to the printed wiring board. The critical thermal stresses and strains are analyzed with the help of two and three-dimensional finite element models. The effect of solder voids and incomplete bonding is also investigated. The paper also shows how fatigue life estimations can be made using q generalized form of the Manson-Coffin equation even though the maximum solder attach stresses are found to be elastic.

Effects of Ceramic Ball-Grid-Array Package’s Manufacturing Variations on Solder Joint Reliability

1994 ◽  
Vol 116 (4) ◽  
pp. 242-248 ◽  
Author(s):  
Teh-Hua Ju ◽  
Wei Lin ◽  
Y. C. Lee ◽  
Jay J. Liu
Keyword(s):  
Fatigue Life ◽  
Solder Joint ◽  
Solder Joints ◽  
Ball Grid Array ◽  
Printed Wiring Board ◽  
Ceramic Ball ◽  
Solder Volume ◽  
Bga Package ◽  
Reliability Of Solder Joints ◽  
Wiring Board

The effects of manufacturing variations on the reliability of solder joints between a ceramic ball grid array (BGA) package and a printed wiring board (PWB) are investigated. Two cases are studied, namely, with and without spacers between the BGA package and the PWB to maintain the solder joint height. Manufacturing variations considered include changes in solder volume, joint height, and pad size. To evaluate the effect of manufacturing variations on reliability, every possible solder joint profile is first derived. The maximum strain is calculated next. Finally, the fatigue life is predicted. The calculations show that these manufacturing variations change the joint profile, and subsequently affect the fatigue life. Since the package is heavy, the use of spacers is necessary to control the solder joint height for reliable connections, and to maintain a large gap for cleaning. The solder joints formed with the use of spacers, may have convex, cylindrical or concave profiles. The concave solder joints are preferred, since they have long fatigue lives and are less sensitive to the manufacturing variations. For the convex solder joints, their fatigue lives are strongly affected by the joint height variation caused by package warpage and by the combined effects of solder volume and pad size.

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.

SCHEDULING OF PRINTED WIRING BOARD ASSEMBLY IN SURFACE MOUNT TECHNOLOGY LINES

2002 ◽  
Vol 11 (01) ◽  
pp. 1-17 ◽  
Author(s):  
TADEUSZ SAWIK ◽  
ANDREAS SCHALLER ◽  
THOMAS M. TIRPAK
Keyword(s):  
Surface Mount Technology ◽  
Printed Wiring Board ◽  
Surface Mount ◽  
Wiring Board

Warpage Measurement Using Projection Moire´ System and Two Automatic Image Segmentation Algorithms

2007 ◽  
Author(s):  
Wei Tan ◽  
I. Charles Ume
Keyword(s):  
Image Segmentation ◽  
Electronic Packages ◽  
Printed Wiring Board ◽  
Segmentation Algorithms ◽  
Out Of Plane ◽  
Cte Mismatch ◽  
Image Models ◽  
Wiring Board ◽  
Plane Displacement ◽  
Projection Moire

Out-of-plane displacement (warpage) has been a major reliability concern for board-level electronic packaging. Printed wiring board (PWB) and component warpage results from CTE mismatch among the materials that make up the PWB assembly (PWBA). Warpage occurring during surface-mount assembly reflow processes and normal operations may lead to serious reliability problems. In this paper, a projection moire´ warpage measurement system and two types of automatic image segmentation algorithms were presented. In order to use the projection moire´ technique to separately determine the warpage of a PWB and assembled electronic packages in a PWBA, two image segmentation algorithms based on mask image models and active contour models (snakes) were developed. They were used to detect package locations in a PWBA displacement image generated by the projection moire´ system. The performances of the mask image and snake approaches based on their resolutions, processing rates, and measurement efficiencies were evaluated in this research. Real-time composite Hermite surface models were constructed to estimate the PWB warpage values underneath the electronic packages. The above automatic image segmentation algorithms were integrated with the projection moire´ system to accurately evaluate the warpage of PWBs and assembled chip packages individually.

Solder Joint Reliability Assessment for a High Performance RF Ceramic Package

2014 ◽  
Vol 2014 (1) ◽  
pp. 000062-000067 ◽  
Author(s):  
Paul Charbonneau ◽  
Hans Ohman ◽  
Marc Fortin
Keyword(s):  
Solder Joint ◽  
High Performance ◽  
Coefficient Of Thermal Expansion ◽  
Unit Cost ◽  
Reliability Assessment ◽  
Lead Free ◽  
Solder Joint Reliability ◽  
Joint Reliability ◽  
Cte Mismatch ◽  
Life Predictions

The prediction of long term solder joint reliability, (SJR), of microelectronic devices and packaging solutions continues to challenge the microelectronic packaging industry, particularly with the introduction of lead-free materials, the push for higher performance (frequency/speed/thermal) and lower unit cost. High performance packages are generally custom designed and therefore have minimal industry data on configuration specific reliability performance. In this application, the package substrate coefficient of thermal expansion, (CTE), was closely matched to the die resulting in a relatively large CTE mismatch between the package and organic PCB. In addition, the package RF and thermal performance requirements required this particular solution to be configured as a “cavity down” perimeter ball array with a large central ground pad to electrically couple the package to the PCB. Given the package's unique design requirements and CTE mismatch, even modest daily temperature swings of 20°C usually found in a controlled or “Central Office” environment could have an adverse impact on the interconnect reliability. This study provides an overview of the solder joint reliability assessment methodologies performed for a custom design lead-free, high performance RF package as part of the requirements to demonstrate compliance to product specifications. SJR life predictions were made for varying package BGA configurations using a multi-tiered approach using constitutive material models, thermo-mechanical finite element simulations, and material specific fatigue models. Empirical accelerated life testing was performed and a life prediction obtained through modeling was validated. Finally, statistical failure distributions were fit to empirical data and discussed in the context of absolute solder life predictions of small fractions unit failures, (100ppm).

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.

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