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

Kim, Jong Min; Farson, Dave F.; Shin, Young-Eui

doi:10.2320/matertrans.44.2175

Cited by 6 publications

(3 citation statements)

References 16 publications

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“…To not only improve adhesion force but also release thermal strain at the interface between a Si chip and Cu pads, underfill materials could be used and they play the role of relaxing the thermal stresses between the interface and the base materials [2,10]. Fig.…”

Section: Resultsmentioning

confidence: 99%

Characteristics of Sn-2.5Ag flip chip solder joints under thermal shock test conditions

et al. 2009

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The interfacial reaction between Cu pad coated with Au/Ni and solder bump of flip chip package, using Sn97.5wt.%-Ag2.5wt%, was studied under thermal shock stress. All joints were subjected to thermal shock test with -65℃/+150℃ temperature range. For the Sn-2.5Ag solder, a scallop-like (Cu,Ni) 6 Sn 5 intermetallic compound was formed in the solder matrix after 20 cycles of thermal shock. (Cu,Ni) 6 Sn 5 was detached from the interface as (Ni,Cu) 3 Sn 4 grew underneath the (Cu,Ni) 6 Sn 5 IMC(Intermetallic Compound), whereas the elements of Sn, Ni and Cu were moved by interdiffusion at the interface between solder alloy and Cu pad. The composition of the IMCs in the solder joints and elemental distribution across the joint interfaces were quantitatively measured with EPMA (electron probe micro analysis). Finally, it was found that the crack initiation point and its propagation path could be influenced by the thermal shock conditions, two underfills, and their properties.

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Section: Resultsmentioning

confidence: 99%

Characteristics of Sn-2.5Ag flip chip solder joints under thermal shock test conditions

et al. 2009

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“…Therefore, the fatigue life of the solder connections was estimated by the number of thermal cycles that resulted in cracking or failure 50 % of the total solder joints in 10 specimens. 12)…”

Section: Methodsmentioning

confidence: 99%

Selection of Proper Fatigue Model for Flip Chip Package Reliability

Shin

Kim

Kim³

et al. 2005

MSF

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There have been diverse fatigue models and approaches to properly estimate solder joint reliability. However, it is one of the most difficult problems to determine which solder constitutive models and fatigue models can be applied best. In this paper, both viscoplastic and elastic-plastic-creep solder constitutive models could be utilized to calculate accumulated inelastic response under 208 K to 423 K(-65 °C to 150 °C) thermal cycling condition. And two different fatigue models, Darveaux and creep-fatigue model were applied to find solder joints fatigue life for flip chip assembly. Moreover, each fatigue life was compared to experimental result for the validation of finite element analysis. The actual number of cycles to failure was obtained from cross sectional view of the package with SEM.

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“…Many thermal fatigue tests on IC packages have been performed. Kim et al 5 found that the introduction of an underfill resin reduced the maximum stress at the solder joint of a ball grid array (BGA) package by approximately 60%, and the fatigue life under a −65°C/150°C thermal cycle was increased by approximately eight times compared with that without the underfill resin. Thus, it was concluded that the underfill resin was effective in improving the connection reliability.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of thermal fatigue crack propagation in underfill resin materials for electronic packages

Watanabe

Yamaguchi²,

Enomoto³

et al. 2022

Fatigue Fract Eng Mat Struct

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To improve the fatigue life of electronic packages, it is necessary to clarify thermal fatigue characteristics of underfill resin materials. In this study, a new setup for measuring thermal fatigue crack growth was developed, and the effects of thermal cycle conditions and silica filler contents on fatigue crack propagation were investigated. The results show that the likelihood of crack initiation increased with the filler content and the temperature of the thermal cycles. Comparing the results with those from mechanical fatigue tests, crack initiation and propagation occurred at lower ΔK and the crack growth rates were higher for thermal fatigue. Observations of the fracture surface revealed that the cracks propagated inside the underfill resin, which resulted in smaller crack growth resistance than that in mechanical fatigue. The addition of fillers introduced a crack propagation path at the interface between fillers and resins and enhanced the crack propagation resistance in thermal fatigue.

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Improvement of Board Level Reliability for μBGA Solder Joints Using Underfill

Cited by 6 publications

References 16 publications

Characteristics of Sn-2.5Ag flip chip solder joints under thermal shock test conditions

Characteristics of Sn-2.5Ag flip chip solder joints under thermal shock test conditions

Selection of Proper Fatigue Model for Flip Chip Package Reliability

Evaluation of thermal fatigue crack propagation in underfill resin materials for electronic packages

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