From Leaded to Lead Free Assembly and New Packaging Technology Challenges

Lavoie, H.; Paquet, M.-C.; Sylvestre, Julien; Ouimet, S.; Duchesne, Éric; Barbeau, Stephane; Gauvin, M.; Oberson, Valerie

doi:10.1109/ectc.2007.373968

Cited by 9 publications

(3 citation statements)

References 3 publications

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“…The voids initiate a crack, which propagates inwards during thermal cycling. The root cause of the voids (crack initiator) may be due to moisture contamination introduced by the moisture preconditioning of the solder joint package (Lavoie et al , 2007). Also, nickel corrosion in the BGA pad (ENIG) can also create a void.…”

Section: Resultsmentioning

confidence: 99%

Numerical investigation of thermal fatigue crack growth behavior in SAC305 BGA solder joints

Apalowo,

Abas,

Muhamed Mukhtar

et al. 2024

SSMT

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Purpose This study aims to investigate the reliability issues of microvoid cracks in solder joint packages exposed to thermal cycling fatigue. Design/methodology/approach The specimens are subjected to JEDEC preconditioning level 1 (85 °C/85%RH/168 h) with five times reflow at 270°C. This is followed by thermal cycling from 0°C to 100°C, per IPC-7351B standards. The specimens' cross-sections are inspected for crack growth and propagation under backscattered scanning electronic microscopy. The decoupled thermomechanical simulation technique is applied to investigate the thermal fatigue behavior. The impacts of crack length on the stress and fatigue behavior of the package are investigated. Findings Cracks are initiated from the ball grid array corner of the solder joint, propagating through the transverse section of the solder ball. The crack growth increases continuously up to 0.25-mm crack length, then slows down afterward. The J-integral and stress intensity factor (SIF) values at the crack tip decrease with increased crack length. Before 0.15-mm crack length, J-integral and SIF reduce slightly with crack length and are comparatively higher, resulting in a rapid increase in crack mouth opening displacement (CMOD). Beyond 0.25-mm crack length, the values significantly decline, that there is not much possibility of crack growth, resulting in a negligible change in CMOD value. This explains the crack growth arrest obtained after 0.25-mm crack length. Practical implications This work's contribution is expected to reduce the additional manufacturing cost and lead time incurred in investigating reliability issues in solder joints. Originality/value The work investigates crack propagation mechanisms of microvoid cracks in solder joints exposed to moisture and thermal fatigue, which is still limited in the literature. The parametric variation of the crack length on stress and fatigue characteristics of solder joints, which has never been conducted, is also studied.

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Section: Resultsmentioning

confidence: 99%

Numerical investigation of thermal fatigue crack growth behavior in SAC305 BGA solder joints

Apalowo,

Abas,

Muhamed Mukhtar

et al. 2024

SSMT

View full text Add to dashboard Cite

show abstract

“…The selection of this particular large die and small chip to substrate standoff reliability test vehicle is critical as it can help reveal, through reliability stresses, important potential underfill failure mechanisms. These mechanisms are underfill delaminations to the different surfaces (chip passivation, chip sidewall and substrate soldermask), chip bump solder fatigue, chip dielectric cracking, underfill material cracking and vertical chip cracking [8].…”

Section: Test Vehicle For Reliability Test Of Vcuf Materialsmentioning

confidence: 99%

Vacuum underfill technology for advanced packaging

Horibe

Paquet

Gaynes

et al. 2011

2011 IEEE 61st Electronic Components and Technology Conference (ECTC)

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We developed vacuum assisted underfill technology for large die (>18 × 18 mm) with fine pitch area array bumps (< 150 m pitch) to solve a critical underfill void issue. Material development and process optimization are the keys to realize a stable process for such an advanced package. It was also confirmed that the newly developed underfill materials have good reliability on the large die package.

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“…As the TCT continues, the applied thermal stress tears open the initial crack (microvoid) along the direction of the stress and propagates the crack in the transverse direction (Ng et al, 2023;Van Mier, 1991). The moisture preconditioning of the BGA package prior to the TCT can be attributed to the formation of the microvoid (crack initiator) (Lavoie et al, 2007). During thermal cycling, vapor pressure is exerted Another possible agent of the crack growth can be attributed to the significant difference in the thermal expansion coefficients (CTE) of the component layers (i.e.…”

Section: Cross-sectional Analysis Of Fracture Growth In Solder Joint ...mentioning

confidence: 99%

Thermal fatigue life prediction and intermetallic compound behaviour of SAC305 BGA solder joints subject to accelerated thermal cycling test

Apalowo,

Abas,

Che Ani

et al. 2024

SSMT

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Purpose This study aims to investigate the thermal fracture mechanism of moisture-preconditioned SAC305 ball grid array (BGA) solder joints subjected to multiple reflow and thermal cycling. Design/methodology/approach The BGA package samples are subjected to JEDEC Level 1 accelerated moisture treatment (85 °C/85%RH/168 h) with five times reflow at 270 °C. This is followed by multiple thermal cycling from 0 °C to 100 °C for 40 min per cycle, per IPC-7351B standards. For fracture investigation, the cross-sections of the samples are examined and analysed using the dye-and-pry technique and backscattered scanning electron microscopy. The packages' microstructures are characterized using an energy-dispersive X-ray spectroscopy approach. Also, the package assembly is investigated using the Darveaux numerical simulation method. Findings The study found that critical strain density is exhibited at the component pad/solder interface of the solder joint located at the most distant point from the axes of symmetry of the package assembly. The fracture mechanism is a crack fracture formed at the solder's exterior edges and grows across the joint's transverse section. It was established that Au content in the formed intermetallic compound greatly impacts fracture growth in the solder joint interface, with a composition above 5 Wt.% Au regarded as an unsafe level for reliability. The elongation of the crack is aided by the brittle nature of the Au-Sn interface through which the crack propagates. It is inferred that refining the solder matrix elemental compound can strengthen and improve the reliability of solder joints. Practical implications Inspection lead time and additional manufacturing expenses spent on investigating reliability issues in BGA solder joints can be reduced using the study's findings on understanding the solder joint fracture mechanism. Originality/value Limited studies exist on the thermal fracture mechanism of moisture-preconditioned BGA solder joints exposed to both multiple reflow and thermal cycling. This study applied both numerical and experimental techniques to examine the reliability issue.

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From Leaded to Lead Free Assembly and New Packaging Technology Challenges

Cited by 9 publications

References 3 publications

Numerical investigation of thermal fatigue crack growth behavior in SAC305 BGA solder joints

Numerical investigation of thermal fatigue crack growth behavior in SAC305 BGA solder joints

Vacuum underfill technology for advanced packaging

Thermal fatigue life prediction and intermetallic compound behaviour of SAC305 BGA solder joints subject to accelerated thermal cycling test

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