Crack Area Analysis of SnPb and SnAg Solder Joints in Plastic Ball Grid Array Packages From Dye Penetration Studies

2003 ◽  
Author(s):  
Changyoung Park ◽  
Jose Marcio Dias Filho ◽  
Donghyun Kim ◽  
Andrew Mawer ◽  
Glenn Y. Masada ◽  
...  
Keyword(s):  
Experimental Data ◽  
Crack Growth ◽  
Solder Joints ◽  
Critical Issue ◽  
Process Conditions ◽  
Electronic Packages ◽  
Plastic Ball ◽  
Aging Conditions ◽  
Snag Solder ◽  
Ball Grid Array Packages

Crack growth in solder joints caused by thermal cycling is a critical issue for reliability in electronic packages. This study presents experimental data on crack growth in SnPb and SnAg solder joints of 357-joint PBGA packages attached to PWBs and subjected to 30-minute, 0°C to 100°C temperature cycles. The board assemblies were exposed to three process conditions upon exiting the solder reflow furnace—air cooled to room temperature, quenched at 0°C, and aged at 150°C (SnPb) or 160°C (SnAg) for 1008 hours—prior to the accelerated thermal cycle testing. At scheduled intervals, the packages were dye-penetrated, removed from the board, and the joint crack areas in several regions measured. The experimental data and statistical analysis of 9000 joints show that SnAg solder joints have half the crack areas of their SnPb counterparts for all regions, cycles and aging conditions. For both solders, the joints located under the die edge have the largest cracks of any region, and the three adjacent joints at each of the four corners under the die edge are the joints most likely to have the largest crack areas. Comparing aging conditions, the differences in the means of % crack area for SnPb packages were not statistically different, but for SnAg packages, the aged joints had 50% smaller crack areas than non-aged joints (air and quench).

Modeling and Analysis of Crack Growth in SnPb and SnAgCu Solder Joints in PBGA Packages: Part II — Crack Propagation

2003 ◽  
Author(s):  
Donghyun Kim ◽  
Andrew Mawer ◽  
Glenn Y. Masada ◽  
Tess J. Moon
Keyword(s):  
Crack Propagation ◽  
Crack Growth ◽  
Solder Joints ◽  
Propagation Model ◽  
Modeling And Analysis ◽  
Snagcu Solder ◽  
Secondary Cracks ◽  
Aging Conditions ◽  
Length Data ◽  
Crack Growth Rates

Part II of this paper describes an experimental and analytical study of crack propagation in SnPb and SnAgCu solder joints in 357-PBGA packages exposed to 30-minute thermal cycles of 0 to 100°C. Experimental results show that cracks propagate faster at the package interface than at the board interface; secondary cracks from at the package interface, but grow much slower than the primary cracks; and crack growth rates in SnPb joints are about 50% larger than in SnAgCu joints. A crack propagation model, developed using the fracture mechanics approach, calculates the energy release rate at the crack tip. Using this rate and experimental crack length data, crack propagation rates were computed. Simulation results show the effects of solder type and aging conditions on crack propagation rates and the effects of the number of cracks in a joint on crack propagation life.

Modeling and Analysis of Crack Growth in SnPb and SnAgCu Solder Joints in PBGA Packages: Part I — Crack Initiation

2003 ◽  
Author(s):  
Donghyun Kim ◽  
Andrew Mawer ◽  
Glenn Y. Masada ◽  
Tess J. Moon
Keyword(s):  
Crack Initiation ◽  
Solder Joints ◽  
Void Formation ◽  
Grain Coarsening ◽  
Modeling And Analysis ◽  
Snagcu Solder ◽  
Secondary Cracks ◽  
Plastic Ball ◽  
Accelerated Thermal Cycling ◽  
Ball Grid Array Packages

Solder joints in electronic packages deform by creep and undergo a microstructural evolution process that includes grain coarsening, voiding, microcracking, and macrocracking. This paper describes an FEM model of the crack initiation process of SnPb and SnAgCu solder joints in 357 plastic ball grid array packages for different aging conditions and simulated under 0–100°C accelerated thermal cycling tests. The simulations show that 1) cracks initiate at the package interface first, and then at the opposite side of the board interface; 2) secondary cracks initiate at the opposite end of the primary crack at the joint interfaces; 3) no secondary cracks occur at the package interface of ages SnPb joints, since compressive stresses oppose void formation; and 4) it takes longer to initiate cracks in SnAgCu joints than SnPb joints. The damage process in the solder joints was simulated from grain coarsening, voiding, to microcracking, with SnAgCu joints not undergoing grain coarsening due to their stable microstructure. The model results were consistent with experimental results in the number and location of cracks in the joints.

Strain Energy Density Criterion for Reliability Life Prediction of Solder Joints in Electronic Packaging

2004 ◽  
Vol 126 (3) ◽  
pp. 398-405 ◽  
Author(s):  
I. Guven ◽  
V. Kradinov ◽  
J. L. Tor ◽  
E. Madenci
Keyword(s):  
Growth Rate ◽  
Crack Growth Rate ◽  
Energy Density ◽  
Crack Growth ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Life Prediction ◽  
Solder Joints ◽  
Intrinsic Property ◽  
Electronic Packages

This study concerns the prediction of crack growth rate for solder joints in electronic packages under thermal cycling. The crack growth rate, which is dependent on the intrinsic solder property and the current stress state, is calculated based on the strain energy density criterion. The critical value of the strain energy density represents the intrinsic property of the solder. The comparison of the crack growth predictions with the experimental measurements demonstrates the applicability of the strain energy density criterion for the reliability life prediction of solder joints.

Maximizing Solder Joint Reliability Through Optimal Shape Design

1997 ◽  
Vol 119 (3) ◽  
pp. 149-155 ◽  
Author(s):  
A. M. Deshpande ◽  
G. Subbarayan ◽  
R. L. Mahajan
Keyword(s):  
Fatigue Life ◽  
Solder Joint ◽  
Numerical Optimization ◽  
Solder Joints ◽  
Optimization Techniques ◽  
Approximation Schemes ◽  
Design Parameters ◽  
Electronic Packages ◽  
Considerable Difficulty ◽  
Plastic Ball

The automated search techniques from the field of numerical optimization provide tools that enable optimal design of electronic packages in general, and solder joints in particular. However, there is considerable difficulty in using these procedures for solder joints since the estimation of fatigue life is computationally very expensive. In this paper, global approximation schemes based on designed experiments, linear regression models, and artificial neural network models are developed to approximate the fatigue life as a function of solder joint design parameters. Since these approximate surfaces are inexpensive to evaluate, their use with the numerical optimization techniques leads to a computationally efficient method for optimizing electronic packages. The developed techniques are demonstrated using the 225 I/O Plastic Ball Grid Array (PBGA) package, manufactured by Motorola, Inc. An exact optimization of the solder joints (without approximations) is also carried out and used as a basis for comparing the accuracy and efficiency of the developed methods.

Backside Application of Acoustic Micro Imaging (AMI) on Plastic Ball Grid Array (PBGA) and Plastic Quad Flat Pack (PQFP) Packages

2004 ◽  
Author(s):  
Luis A. Curiel ◽  
Andrew J. Komrowski ◽  
Daniel J.D. Sullivan
Keyword(s):  
Ball Grid Array ◽  
Acoustic Microscopy ◽  
Electronic Packages ◽  
Nondestructive Technique ◽  
Molding Compound ◽  
Microscopy Technique ◽  
Plastic Ball ◽  
Die Surface ◽  
Plastic Ball Grid Array ◽  
Bond Pads

Abstract Acoustic Micro Imaging (AMI) is an established nondestructive technique for evaluation of electronic packages. Non-destructive evaluation of electronic packages is often a critical first step in the Failure Analysis (FA) process of semiconductor devices [1]. The molding compound to die surface interface of the Plastic Ball Grid Array (PBGA) and Plastic Quad Flat Pack (PQFP) packages is an important interface to acquire for the FA process. Occasionally, with these packages, the standard acoustic microscopy technique fails to identify defects at the molding compound to die surface interface. The hard to identify defects are found at the edge of the die next to the bond pads or under the bonds wires. This paper will present a technique, Backside Acoustic Micro Imaging (BAMI) analysis, which can better resolve the molding compound to die surface interface at the die edge by sending the acoustic signal through the backside of the PBGA and PQFP packages.

Area Array Solder Joints for Passive Alignment

1992 ◽  
Vol 264 ◽  
Author(s):  
John McGroarty ◽  
Boris Yost ◽  
Peter Børgesen ◽  
Che-Yu Li
Keyword(s):  
Optical Interconnects ◽  
Solder Joints ◽  
Cost Effective ◽  
Scientific Basis ◽  
Electronic Packages ◽  
Liquid Solder ◽  
Area Array ◽  
Cost Effective Method ◽  
Passive Alignment

AbstractPassive alignment techniques using area array solder joints are currently under investigation as a cost effective method of achieving electro-optical interconnects in electronic packages. Several investigators have developed models that describe the shapes of and forces produced by the liquid solder drops during reflow. These models are reviewed to provide a scientific basis for the application of such techniques.

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