The Effect of Stencil Printing Optimization on Reliability of CBGA and PBGA Solder Joints

1998 ◽  
Vol 120 (1) ◽  
pp. 54-60 ◽  
Author(s):  
Y. Li ◽  
R. L. Mahajan ◽  
G. Subbarayan
Keyword(s):  
Fatigue Life ◽  
Solder Joints ◽  
Maximum Strain ◽  
Stencil Printing ◽  
Eutectic Solder ◽  
Printing Process ◽  
Ceramic Ball ◽  
Ball Grid Arrays ◽  
Solder Volume ◽  
Plastic Ball

As a follow-up and conclusion to previous work in stencil printing process modeling and optimization (Li et al., 1996), we investigate the effect of stencil printing optimization on the reliability of the ceramic and plastic ball grid arrays. For ceramic ball grid arrays, the eutectic solder fillet shape is calculated using a series of simple mathematical equations. The thermal strain distributions within the solder joints after two cycles of accelerated thermal cycling test are estimated using three-dimensional finite element models. The modified Coffin-Manson relationship is applied to calculate the mean fatigue lives of the solder joints. The results reveal that an optimized stencil printing process significantly reduces variation in the fatigue life of ceramic ball grid arrays. The results also show that the fatigue life of ceramic ball grid arrays is very sensitive to the card-side solder volume. The maximum strain region shifts from the card-side eutectic solder to the module side as the card-side eutectic solder volume increases. This shift in maximum strain suggests that there exists an optimum ratio between the card-side solder volume and the module-side solder volume for the reliability of a given ceramic ball grid array design. The implications of this for the package developers and users are discussed. The calculations indicate that the fatigue life of plastic ball grid arrays is almost insensitive to the card-side solder volume.

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.

scholarly journals Experimental Study on the Reliability of PBGA Electronic Packaging under Shock Loading

Electronics ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 279 ◽  
Author(s):  
Jiang Shao ◽  
Hongjian Zhang ◽  
Bo Chen
Keyword(s):  
Fatigue Life ◽  
Electronic Packaging ◽  
Failure Modes ◽  
Solder Joints ◽  
Optical Microscope ◽  
Micro Cracks ◽  
Plastic Ball ◽  
Plastic Ball Grid Array ◽  
Aeronautical Industry ◽  
The Relationship

Plastic Ball Grid Array (PBGA) one of the most important electronic packaging methods, is widely used in aeronautical industry field. According to the JEDEC standard, shock tests of PBGA assemblies are conducted under different loading conditions. Several important parameters, such as the fatigue life of PBGA assemblies, the relationship between solder joint positions and fatigue life, the relationship between strain energy density and fatigue life, are analyzed based on experiment results. The failure modes of PBGA assemblies are studied by optical microscope (OM). The results show that during the shock tests, the strains of the solder joints near the center of the specimen are larger than other positions, and these solder joints are prone to form micro cracks. With the increase of the shock times, these micro cracks extend rapidly which will eventually cause the failure of the PBGA electronic packaging.

CBGA Solder Fillet Shape Prediction and Design Optimization

1998 ◽  
Vol 120 (2) ◽  
pp. 118-122 ◽  
Author(s):  
Y. Li ◽  
R. L. Mahajan
Keyword(s):  
Mathematical Method ◽  
Fatigue Life ◽  
Solder Ball ◽  
Surface Model ◽  
Underlying Assumption ◽  
Eutectic Solder ◽  
Factors Affecting ◽  
Ball Size ◽  
Solder Volume ◽  
Set Up

In this paper, we first present a mathematical method that can be used to predict the eutectic solder fillet shape for ceramic ball grid array joints. An underlying assumption is that the solder fillets on both the module and the card sides can be represented as arcs. The fillets’ profiles are then calculated for the factors affecting the shape including solder volume, pad size, solder ball size, the wetting angle between eutectic solder and solder ball, and the gap between solder ball and pad. The second part of the paper focuses on design for reliability and investigates the effect of the interactions between the card-side and the module-side solder fillets on CBGA solder joint reliability. To this end, a central composite design of experiment is set up to systematically vary the pad size and the eutectic solder volume on both the module and the card sides. For each of the design settings, the proposed mathematical method is used to calculate the solder fillet shape. Using ABAQUS and the modified Coffin-Manson relationship, the mean fatigue life is predicted. The implications of the simulations are discussed. In addition, a response surface model is presented to find the optimum settings for maximum reliability. Finally, a comparison is made for the fatigue life predictions obtained using the proposed mathematical method and the linear solder fillet assumption.

A Systematic Approach for Determining the Thermal Fatigue-Life of Plastic Ball Grid Array (PBGA) Lead-Free Solder Joints

2005 ◽  
Author(s):  
John Lau ◽  
Ricky Lee ◽  
Walter Dauksher ◽  
Dongkai Shangguan ◽  
Fubin Song ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Thermal Fatigue ◽  
Solder Joints ◽  
Ball Grid Array ◽  
Lead Free ◽  
Lead Free Solder ◽  
Thermal Fatigue Life ◽  
Plastic Ball ◽  
Plastic Ball Grid Array ◽  
Free Solder

Reliability of plastic ball grid array (PBGA) SnAgCu lead-free solder joints is investigated. Emphasis is placed on the design for reliability (DFR) of lead-free solder joints. In particular, the thermal-fatigue life of the lead-free solder joints of a PBGA package assembly is predicted and compared with thermal cycling test results.

Thermal Fatigue-Life Prediction of Lead-Free Solder Joints

2004 ◽  
Author(s):  
John Lau ◽  
Ricky Lee ◽  
Dongkai Shangguan
Keyword(s):  
Fatigue Life ◽  
Thermal Fatigue ◽  
Life Prediction ◽  
Solder Joints ◽  
Lead Free ◽  
Lead Free Solder ◽  
Thermal Fatigue Life ◽  
Plastic Ball ◽  
Plastic Ball Grid Array ◽  
Free Solder

Reliability of lead-free solder joints is investigated. Emphasis is placed on the design for reliability (DFR) of lead-free solder joints. In particular, the thermal-fatigue life of the lead-free solder joints of a plastic ball grid array (PBGA) package assembly is predicted and discussed.

Solder paste volume effects on assembly yield and reliability for bottom terminated components

2017 ◽  
Vol 29 (2) ◽  
pp. 99-109 ◽  
Author(s):  
Sai Srinivas Sriperumbudur ◽  
Michael Meilunas ◽  
Martin Anselm
Keyword(s):  
Thermal Cycling ◽  
Solder Joints ◽  
Inspection System ◽  
Solder Paste ◽  
Stencil Printing ◽  
Printing Process ◽  
Content Type ◽  
Volume Limit ◽  
Solder Paste Printing ◽  
Low Volume

Purpose Solder paste printing is the most common method for attaching surface mount devices to printed circuit boards (PCB), and it has been reported that a majority of all assembly defects occur during the stencil printing process. It is also recognized that the solder paste printing process is wholly responsible for the solder joint formation of leadless package technologies such as land grid array (LGA) and quad-flat no-lead (QFN) components and therefore is a determining factor in the long-term reliability of said devices. The aim of this experiment is to determine the acceptable lower limit for solder paste volume deposit tolerances during stencil printing process to ensure both good assembly yield and reliability expectations. Design/methodology/approach Stencils with modified aperture dimensions at particular locations for LGA and QFN package footprints were designed to vary the solder paste volume deposited during the stencil printing process. Solder paste volumes were measured using solder paste inspection system. Low volume solder paste deposits were generated using the modified stencil designs to evaluate assemble yield. Accelerated thermal cycling (ATC) was used to determine the reliability of the solder joints. Failure analysis was used to determine if the failure was attributed to the low paste volume locations. Findings Solder joints formed with nominal paste volume survived longer in ATC compared to intentionally low volume joints. Transfer efficiency numbers for both good assembly yield and good reliability are reported for LGA and QFN devices. A lower volume limit is reported for leadless devices that should not significantly affect yield and reliability in thermal cycling. Originality/value Very little literature is available on solder paste volume tolerance limits in terms of assembly yield and reliability. Manufacturers often use ±50 or ±30 per cent of stencil aperture volume with no evidence of its effectiveness in determining yield and reliability of the solder joints.

scholarly journals Addressing Off-Centered Ball through Solder Paste Material Evaluation

2020 ◽  
pp. 15-18
Author(s):  
B. C. Bacquian ◽  
F. R. Gomez ◽  
E. Graycochea Jr. ◽  
N. Gomez
Keyword(s):  
Solder Joints ◽  
Semiconductor Device ◽  
Solder Paste ◽  
Stencil Printing ◽  
Printing Process ◽  
Material Evaluation ◽  
Centered Ball

Stencil printing using solder paste material is one of the challenging processes in semiconductor assembly manufacturing. During evaluation of a semiconductor device, off-centered ball issue    was encountered. The study aimed to mitigate the off-centered ball issue at stencil printing  process by exploring the effect of different solder paste materials. Both solder paste materials  were cured using the same reflow condition. However, solder paste material 1 (S1) resulted  to cold solder joints while material 2 (S2) showed cured solder paste characteristic. With S2 material used in stencil printing, the off-centered ball occurrence was eventually eliminated. For future works, the solder paste material and configuration could be used for devices with similar requirement.

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.

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