Board level reliability of a stacked CSP subjected to cyclic bending

Wu, Jenq-Dah; Ho, Seong; Huang, Chun-Yueh; Liao, C.C; Zheng, P.J.; Hung, S.C.

doi:10.1016/s0026-2714(01)00241-4

Cited by 10 publications

(4 citation statements)

References 4 publications

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“…While in the middle of the solder joint there is less IMC and a smaller crystal lattice. According to the former study [2,3,6,[11][12][13][15][16][17][18][19][20], the bottom/top area of the solder joint is the most dangerous area during fatigue failure. So there is a conclusion that the IMC's appearance is the important phenomena before fatigue failure.…”

Section: Experimental Discussionmentioning

confidence: 99%

“…The reliability of SMT solder joints is now more important than before Supported by Astronautic Technology Innovation Fund because only one solder joint's failure may cause a catastrophic result and give a serious worldwide influence. However, there has been little study on the solder joints' reliability in this serious condition although a lot of papers have been done in some kinds of thermal cycle load or in some kind of vibration/shock condition or in thermal-mechanical load [1][2][3][4][5][6][7][8][9][10]. These studies, although, may give some guidance to astronautic solder joints' reliability, they are not adapted to evaluate astronautic solder joints' reliability accurately.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Astronautic PBGA (plastic ball grid array) solder joints’ reliability: under successive-high acceleration shock condition

Guo

Zhao

Zhu

et al. 2005

Int J Adv Manuf Technol

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Along with the development of the astronautic industry, more and more SMT solder joints have been used in missile, rocket and other important equipments where the environment of astronautic equipments is more serious and complex than that in normal conditions. In this present paper, reliability of a kind of astronautic PBGA256 assembly sample is considered under the successive-high acceleration shock condition. During the test, the thickness of InterMetal Compounds (IMCs) is considered and calculated by an equation to compare with each other. It is found that the growth rate of the phase of Cu 6 Sn 5 /Cu 3 Sn and Ag 3 Sn is larger that other phases. So in the finial micrographs the phase of Cu 6 Sn 5 /Cu 3 Sn and Ag 3 Sn is easy to observed. After 3 hours' successive-high acceleration (7g) shock, although the sample PBGA solder joints are still in good condition and have no obvious crack by SEM, in the micrograph of the solder joint there are some special phenomena that is not the same as that in normal condition or thermal fatigue load.

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Section: Experimental Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Astronautic PBGA (plastic ball grid array) solder joints’ reliability: under successive-high acceleration shock condition

Guo

Zhao

Zhu

et al. 2005

Int J Adv Manuf Technol

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“…Studies by Le Coq et al . (2010) and Wu et al . (2002) report the fatigue life for various types of packaging, whereby cyclic bending testing is used to identify the failure of solder joints and is characterized by the Weibull model, combined with experimental testing.…”

Section: Introductionmentioning

confidence: 97%

Investigation and prediction of solder joint failure analysis for ball grid array package subject to mechanical bending environment

Lan

2017

SSMT

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Purpose The purpose of this study was to investigate the changes in solder joint stress when subjected to mechanical bending. The analytical theory pertaining to the stresses in the solder joint between the components (including the molding compound, the chip and the substrate) was described, and the printed circuit board (PCB) with a discontinuity function when the PCB assembly is subjected to mechanical bending was developed. Thus, the findings reported here may lead to a better understanding of the solder joint failure based on the Physics of Failure model. Design/methodology/approach This paper discusses the analytical model for calculating the stress in solder joints, as well as presents a simulation model that can be used for calculating the strain energy density of solder joint. First, the multilayer plate theory is used in discussing the composite material for the component, including the molding compound, the silicon chip and the substrate, or the PCB, including the copper layers, the fiber and the epoxy. Finally, the complete structure of the analytical model developed as a part of this current work is presented. Findings For the analytical model of multilayer structures in which the interconnection layer is discrete, mechanical bending has been modeled with respect to varying silicon chip length. The analytical model that describes the stress of the outermost solder joint experiences is chosen, as this is the typical solder joint failure. The analytical model can be applied to discrete solder joints, which are evaluated by calculating the matrix form. Owing to its use of the matrix equation, the analytical model can be highly combinatorial and thus more capable of calculating the solution. Research limitations/implications The analytical solution based on a simple concept was presented and validated using the finite element model for the stress experienced by solder joints subjected to mechanical bending. To verify that the simulation represents a real PCB case, the authors use the finite element method (FEM) to compare their case with the multilayer plate theory. Owing to the good agreement between the theory and simulation results, the authors conclude that the multilayer plate theory can be correctly applied in multilayer PCB and be used in an analytical model for the PCB assembly subjected to mechanical bending. Practical implications Owing to the good agreement between the theory and simulation results, the authors conclude that the multilayer plate theory can be correctly applied in multilayer PCB and be used in an analytical model for the PCB assembly subjected to mechanical bending. Social implications The analytical model is validated with the FEM model and provides the way to physically examine the solder joint failure mechanism. In this paper, the analytical model is developed as a means to assess the solder joint stress subjected to mechanical bending. Originality/value The analytical model treats the solder joint as discrete and has been successfully validated against the finite element model. The complete structure model (the second analytical model) is presented to discuss the effects of varying silicon chip length on the normal stress in solder joints. When the silicon chip length exceeds to 80 per cent of the total package length, the stress of the outermost solder joint increases rapidly. The design analysis findings have suggested that the failure of the outermost solder joint subjected to mechanical bending on the PCB assembly can be reduced by analyzing the analytical model.

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“…[1][2][3] A major issue in applying BGA packages and CSP has been board-level reliability, [4][5][6] which is a particularly critical issue in portable electronic products such as PDAs, cellular phones, etc. In these products, harsh service conditions such as mechanical impacts, 7) vibration and bending 8,9) add to cyclical thermal stresses induced by differences in the Coefficient of Thermal Expansion (CTE) between the chip and the printed circuit board (PCB). 10) Although the board-level reliability of BGA and CSP has been dramatically improved in last few years, stress-induced failure in BGA/CSP interconnections is still a problem and there have been numerous studies aimed at understanding and addressing the failure of solder joints due to thermal fatigue.…”

Section: Introductionmentioning

confidence: 99%

Improvement of Board Level Reliability for μBGA Solder Joints Using Underfill

2003

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The underfilling BGA as an alternative to direct chip attachment for high density packaging technologies have been developed. This paper discusses the thermomechanical and metallurgical effects of underfill material and the resulting improvement in board level reliability for underfilled BGA assemblies. Finite element analysis (FEA) models were developed to predict the thermal fatigue life of the solder joints during thermal cycling tests for BGA assemblies without and with underfill material. FEA predicted that the stress concentrated in the solder at the crevice between the solder ball and upper substrate was approximately 60 percent of the stress without underfill. Subsequently, the predicted fatigue life was as much as 10 times higher for the underfilled assemblies. The thermal fatigue failure of BGA solder joints was also investigated experimentally using thermal cycle testing with subsequent solder joint analysis by scanning electron microscope (SEM) and energy dispersive X-ray (EDX). The experiments revealed that solder joint failure was caused by propagation of cracks that initiated in the solder at the upper interface between the solder ball and copper pad. The fatigue life of the underfilled assemblies was about 8 times that of the assemblies without underfill. The results showed that the underfill material can play an important role in improving board level reliability for BGA solder joints in harsh environments.

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Board level reliability of a stacked CSP subjected to cyclic bending

Cited by 10 publications

References 4 publications

Astronautic PBGA (plastic ball grid array) solder joints’ reliability: under successive-high acceleration shock condition

Astronautic PBGA (plastic ball grid array) solder joints’ reliability: under successive-high acceleration shock condition

Investigation and prediction of solder joint failure analysis for ball grid array package subject to mechanical bending environment

Improvement of Board Level Reliability for μBGA Solder Joints Using Underfill

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Board level reliability of a stacked CSP subjected to cyclic bending

Cited by 10 publications

References 4 publications

Astronautic PBGA (plastic ball grid array) solder joints’ reliability: under successive-high acceleration shock condition

Astronautic PBGA (plastic ball grid array) solder joints’ reliability: under successive-high acceleration shock condition

Investigation and prediction of solder joint failure analysis for ball grid array package subject to mechanical bending environment

Improvement of Board Level Reliability for &mu;BGA Solder Joints Using Underfill

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Improvement of Board Level Reliability for μBGA Solder Joints Using Underfill