Underfilled BGAs for ceramic BGA packages and board-level reliability

Burnette, T.; Johnson, Z.; Koschmieder, T.; Oyler, W.

doi:10.1109/ectc.2000.853329

Cited by 22 publications

(13 citation statements)

References 3 publications

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“…Underfill may also be used for CBGAs in order to enhance solder joint reliability [26]. When underfill is used, the coefficients and the parameters in the universal fatigue life equation will also change.…”

Section: Other Considerationsmentioning

confidence: 99%

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Universal fatigue life prediction equation for ceramic ball grid array (CBGA) packages

Perkins

Sitaraman

2007

Microelectronics Reliability

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Section: Other Considerationsmentioning

confidence: 99%

“…As a result, each researcher resorts to solving for the constants C 1 and n with their own numerical models and experimental data. For exam- [23,24], Wong et al [2], Xie and Wang [25], and Burnette et al [26]. No two researchers consistently used the same FEM assumptions or material models/properties.…”

Section: Introductionmentioning

confidence: 97%

Universal fatigue life prediction equation for ceramic ball grid array (CBGA) packages

Perkins

Sitaraman

2007

Microelectronics Reliability

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“…2,11) Consequently, BGA/CSP could be used in small electronic devices such as cellular phones. [12][13][14] It was found that one of the main factors that affects the board-level reliability for BGA-type packages is the standoff height (SOH) -the distance between the package and the board. As SOH decreases, the thermal fatigue life of the solder joint also decreases.…”

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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“…Underfills B and C increase the accumulated strain values. The trend of increasing solder strain with increasing underfill CTE has also been observed for CBGA assemblies [2]. …”

Section: Effect Of Underfill On Solder Joint Strainmentioning

confidence: 62%

“…Burnette et al [2] have studied the board-level reliability of underfilled ceramic BGA packages. In flip-chip on board (FCOB) assemblies, underfill is often used to enhance the reliability of solder joints.…”

Section: Introductionmentioning

confidence: 99%

Effect of underfill on BGA reliability

Pyland

Pucha²,

Sitaraman³

2001 Proceedings. 51st Electronic Components and Technology Conference (Cat. No.01CH37220)

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The effect of underfill on various thermo-mechanical reliability issues in SBGA (Super Ball Grid Array) packages is studied in this paper. Non-linear finite element models with underfill and no underfill have been developed taking into consideration the process-induced residual stresses. In this study, the solder is modeled as time and temperaturedependent, while other materials are modeled temperature and direction-dependent, as appropriate.The stress/strain variations in solder joints due to thermal cycling are analyzed. The effect of underfill is studied with respect to magnitude and location of time-independent plastic strain, timedependent creep strain and total inelastic strain in solder balls. The possibility of delamination at the interposer-underfill interface as well as board-underfill interface is studied with the help of qualitative interfacial stress analysis. Results on SBGA packages indicate that the underfill does not always enhance BGA reliability, and that the properties of the underfill have a significant role in the overall reliability of the BGA solder balls. IntroductionWith the increasing need for higher performance, smaller size, and higher pin count, ball grid array (BGA) and chipscale packages (CSP) are being increasingly used in many applications. Burnette et al.[2] have studied the board-level reliability of underfilled ceramic BGA packages. In flip-chip on board (FCOB) assemblies, underfill is often used to enhance the reliability of solder joints. However, in the case of BGAs and CSPs, underfilling is done under select instances, typically to enhance reliability and/or to provide environmental protection to the solder balls.The Super Ball Grid Array (SBGA) is a BGA package developed for higher thermal and electrical performance. In an ongoing research program at Georgia Tech, test vehicles with SBGA packages are being studied for military aircraft applications. When SBGA packages are used in military aircraft applications, the second-level solder balls are often encapsulated with an underfill for preventing possible moisture condensation around the solder balls. Although the underfill is used for such environmental protection purposes, the effect of underfilling SBGA packages on thermomechanical reliability is not adequately studied. In the ongoing research program, computational models are developed to understand the reliability of SBGA packages with various underfills.

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Underfilled BGAs for ceramic BGA packages and board-level reliability

Cited by 22 publications

References 3 publications

Universal fatigue life prediction equation for ceramic ball grid array (CBGA) packages

Universal fatigue life prediction equation for ceramic ball grid array (CBGA) packages

Improvement of Board Level Reliability for μBGA Solder Joints Using Underfill

Effect of underfill on BGA reliability

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Underfilled BGAs for ceramic BGA packages and board-level reliability

Cited by 22 publications

References 3 publications

Universal fatigue life prediction equation for ceramic ball grid array (CBGA) packages

Universal fatigue life prediction equation for ceramic ball grid array (CBGA) packages

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

Effect of underfill on BGA reliability

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Improvement of Board Level Reliability for μBGA Solder Joints Using Underfill