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.

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.

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).

Predictive Failure Analysis of Solder Joints with Simultaneous High Speed EBSD and EDS

2018 ◽  
Author(s):  
J. Lindsay ◽  
P. Trimby ◽  
J. Goulden ◽  
S. McCracken ◽  
R. Andrews
Keyword(s):  
High Speed ◽  
Solder Joints ◽  
Phase Distribution ◽  
Bond Failure ◽  
Microstructural Parameters ◽  
Snpb Solder ◽  
Grain Orientations ◽  
Accelerated Thermal Cycling ◽  
The Relationship ◽  
Opening Up

Abstract The results presented here show how high-speed simultaneous EBSD and EDS can be used to characterize the essential microstructural parameters in SnPb solder joints with high resolution and precision. Analyses of both intact and failed solder joints have been carried out. Regions of strain localization that are not apparent from the Sn and Pb phase distribution are identified in the intact bond, providing key insights into the mechanism of potential bond failure. In addition, EBSD provides a wealth of quantitative detail such as the relationship between parent Sn grain orientations and Pb coarsening, the morphology and distribution of IMCs on a sub-micron scale and accurate grain size information for all phases within the joint. Such analyses enable a better understanding of the microstructural developments leading up to failure, opening up the possibility of improved accelerated thermal cycling (ATC) testing and better quality control.

Effect of thermal aging on the interfacial structure of SnAgCu solder joints on Cu

2007 ◽  
Vol 47 (12) ◽  
pp. 2161-2168 ◽  
Author(s):  
Weiqun Peng ◽  
Eduardo Monlevade ◽  
Marco E. Marques
Keyword(s):  
Thermal Aging ◽  
Solder Joints ◽  
Interfacial Structure ◽  
Snagcu Solder

Void Formation and Their Effect on Reliability of Lead-Free Solder Joints on MID and PCB Substrates

2017 ◽  
Vol 66 (4) ◽  
pp. 1229-1237 ◽  
Author(s):  
P. Wild ◽  
T. Grozinger ◽  
D. Lorenz ◽  
A. Zimmermann
Keyword(s):  
Solder Joints ◽  
Void Formation ◽  
Lead Free ◽  
Lead Free Solder ◽  
Free Solder

Quantitative Evaluation of Voids in Lead Free Solder Joints

2015 ◽  
Vol 772 ◽  
pp. 284-289 ◽  
Author(s):  
Sabuj Mallik ◽  
Jude Njoku ◽  
Gabriel Takyi
Keyword(s):  
Solder Bump ◽  
Solder Joints ◽  
Void Formation ◽  
Lead Free ◽  
Lead Free Solder ◽  
Solder Paste ◽  
X Ray ◽  
Size And Shape ◽  
Solder Bumps ◽  
Free Solder

Voiding in solder joints poses a serious reliability concern for electronic products. The aim of this research was to quantify the void formation in lead-free solder joints through X-ray inspections. Experiments were designed to investigate how void formation is affected by solder bump size and shape, differences in reflow time and temperature, and differences in solder paste formulation. Four different lead-free solder paste samples were used to produce solder bumps on a number of test boards, using surface mount reflow soldering process. Using an advanced X-ray inspection system void percentages were measured for three different size and shape solder bumps. Results indicate that the voiding in solder joint is strongly influenced by solder bump size and shape, with voids found to have increased when bump size decreased. A longer soaking period during reflow stage has negatively affectedsolder voids. Voiding was also accelerated with smaller solder particles in solder paste.

A Highly Accelerated Thermal Cycling (HATC) Test for Solder Reliability Assessment in BGA Packages

2007 ◽  
Author(s):  
X. Long ◽  
I. Dutta ◽  
R. Guduru ◽  
R. Prasanna ◽  
M. Pacheco
Keyword(s):  
Thermal Cycling ◽  
Solder Joints ◽  
Low Cycle Fatigue ◽  
Inelastic Strain ◽  
Fatigue Reliability ◽  
Element Analysis ◽  
Mechanical Cycling ◽  
Experimental Apparatus ◽  
Dependent Strain ◽  
Accelerated Thermal Cycling

A thermo-mechanical loading system, which can superimpose a temperature and location dependent strain on solder joints, is proposed in order to conduct highly accelerated thermal-mechanical cycling (HATC) tests to assess thermal fatigue reliability of Ball Grid Array (BGA) solder joints in microelectronics packages. The application of this temperature and position dependent strain produces generally similar loading modes (shear and tension) encountered by BGA solder joints during service, but substantially enhances the inelastic strain accumulated during thermal cycling over the same temperature range as conventional ATC (accelerated thermal cycling) tests, thereby leading to a substantial acceleration of low-cycle fatigue damage. Finite element analysis was conducted to aid the design of experimental apparatus and to predict the fatigue life of solder joints in HATC testing. Detailed analysis of the loading locations required to produce failure at the appropriate joint (next to the die-edge ball) under the appropriate tension/shear stress partition are presented. The simulations showed that the proposed HATC test constitutes a valid methodology for further accelerating conventional ATC tests. An experimental apparatus, capable of applying the requisite loads to a BGA package was constructed, and experiments were conducted under both HATC and ATC conditions. It is shown that HATC proffers much reduced cycling times compared to ATC.

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