Investigation of underfilling BGAs packages – Thermal fatigue

Pham, V.D.; Xu, Jiefeng; Pan, Ke; Wang, Jing; Park, Seungbae; Singh, Charandeep; Wang, Huayan

doi:10.1109/ectc32862.2020.00351

Cited by 18 publications

(3 citation statements)

References 26 publications

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“…Much research shows that solder balls are the weakest link in the electronic packaging system [ 2 , 3 ]. Due to the changes in ambient temperature and Joule heat caused by current interruption, solder balls in electronic packaging systems normally undergo temperature cycling and the subsequent thermal fatigue load by the mismatch of CTE (Coefficient of Thermal Expansion) during long-term service [ 4 ].…”

Section: Introductionmentioning

confidence: 99%

Effects of Voids on Thermal Fatigue Reliability of Solder Joints on Inner Rings in Ball Grid Array Packaging by Finite Element Analysis

Liu

et al. 2023

Micromachines

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Under alternating temperatures, the fatigue failure of solder balls caused by the mismatch of the thermal expansion coefficient is a key problem in a Ball Grid Array (BGA). However, the combined effects of the solder ball location and the size of voids within it can seriously affect the thermal fatigue reliability of BGA solder balls, which can be easily ignored by researchers. Firstly, the thermal fatigue reliability of the board-level solder balls was evaluated by a temperature cycling test of the BGA package at −20 °C–+125 °C. The experimental results showed that the thermal fatigue reliability of the outer ring’s solder joint was lower than that of the inner ring. Secondly, the reliability of the solder balls in the BGA package was studied under the same thermal cycling condition based on finite element analysis (FEA). The influences of voids on fatigue life were investigated. Generally, a linear correlation between the void content and the fatigue life of the inner rings’ solder balls could be identified with a gradually smoothed relationship for solder balls closer to the center. In addition, when the size of the void exceeded a critical volume, the inner ring’s solder ball with the void would fail before the outermost ring. The results of FEA showed that the critical void volume ratio from the second to fifth ring increased from 10.5% to 42.3%. This study provides a valuable reference for the influence of voids on the thermal fatigue reliability of BGA solder balls.

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Section: Introductionmentioning

confidence: 99%

Effects of Voids on Thermal Fatigue Reliability of Solder Joints on Inner Rings in Ball Grid Array Packaging by Finite Element Analysis

Liu

et al. 2023

Micromachines

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“…Moreover, the curing stage was studied numerically to predict the package warpage (Lin and Lee, 2020). In the post-underfill stage, the reliability of underfilled package was evaluated in terms of its structural mechanical behaviours (Sun et al, 2020;Yang et al, 2020;Che et al, 2020) and thermal aspects (Pham et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

Surface energetic-based analytical filling time model for flip-chip underfill process

Abas

2021

SSMT

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Purpose This paper aims to present new analytical model for the filling times prediction in flip-chip underfill encapsulation process that is based on the surface energetic for post-bump flow. Design/methodology/approach The current model was formulated based on the modified regional segregation approach that consists of bump and post-bump regions. Both the expansion flow and the subsequent bumpless flow as integrated in the post-bump region were modelled considering the surface energy–work balance. Findings Upon validated with the past underfill experiment, the current model has the lowest root mean square deviation of 4.94 s and maximum individual deviation of 26.07%, upon compared to the six other past analytical models. Additionally, the current analytically predicted flow isolines at post-bump region are in line with the experimental observation. Furthermore, the current analytical filling times in post-bump region are in better consensus with the experimental times as compared to the previous model. Therefore, this model is regarded as an improvised version of the past filling time models. Practical implications The proposed analytical model enables the filling time determination for flip-chip underfill process at higher accuracy, while providing more precise and realistic post-bump flow visualization. This model could benefit the future underfill process enhancement and package design optimization works, to resolve the productivity issue of prolonged filling process. Originality/value The analytical underfill studies are scarce, with only seven independent analytical filling time models being developed to date. In particular, the expansion flow of detachment jump was being considered in only two previous works. Nonetheless, to the best of the authors’ knowledge, there is no analytical model that considered the surface energies during the underfill flow or based on its energy–work balance. Instead, the previous modelling on post-bump flow was based on either kinematic or geometrical that is coupled with major assumptions.

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“…By tracking movements of exterior features of a structure that appear on digital images captured by cameras, the displacement can be calculated by photogrammetry theory and its modal parameters can be estimated for damage detection. The digital image correlation (DIC) method is a kind of photogrammetry method that measures the full-field deformation of structure in various fields of research, such as for vibration [ 44 ], crack monitoring [ 45 , 46 , 47 ], high-temperature structures [ 48 , 49 , 50 ], electronic packaging [ 51 , 52 , 53 ], and small structures [ 54 , 55 ]. The identification of a whole area displacement field or operating deflection shape (ODS) is one of the most interesting features using the DIC method [ 56 ].…”

Section: Introductionmentioning

confidence: 99%

Dynamic Characteristics and Damage Detection of a Metallic Thermal Protection System Panel Using a Three-Dimensional Point Tracking Method and a Modal Assurance Criterion

Goo

2020

Sensors

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A thermal protection system (TPS) is designed and fabricated to protect a hypersonic vehicle from extreme conditions. Good condition of the TPS panels is necessary for the next flight mission. A loose bolted joint is a crucial defect in a metallic TPS panel. This study introduces an experimental method to investigate the dynamic characteristics and state of health of a metallic TPS panel through an operational modal analysis (OMA). Experimental investigations were implemented under free-free supports to account for a healthy state, the insulation effect, and fastener failures. The dynamic deformations resulted from an impulse force were measured using a non-contact three-dimensional point tracking (3DPT) method. Using changes in natural frequencies, the damping ratio, and operational deflection shapes (ODSs) due to the TPS failure, we were able to detect loose bolted joints. Moreover, we also developed an in-house program based on a modal assurance criterion (MAC) to detect the state of damage of test structures. In a damage state, such as a loose bolted joint, the stiffness of the TPS panel was reduced, which resulted in changes in the natural frequency and the damping ratio. The calculated MAC values were less than one, which pointed out possible damage in the test TPS panels. Our results also demonstrated that a combination of the 3DPT-based OMA method and the MAC achieved good robustness and sufficient accuracy in damage identification for complex aerospace structures such as TPS structures.

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Investigation of underfilling BGAs packages – Thermal fatigue

Cited by 18 publications

References 26 publications

Effects of Voids on Thermal Fatigue Reliability of Solder Joints on Inner Rings in Ball Grid Array Packaging by Finite Element Analysis

Effects of Voids on Thermal Fatigue Reliability of Solder Joints on Inner Rings in Ball Grid Array Packaging by Finite Element Analysis

Surface energetic-based analytical filling time model for flip-chip underfill process

Dynamic Characteristics and Damage Detection of a Metallic Thermal Protection System Panel Using a Three-Dimensional Point Tracking Method and a Modal Assurance Criterion

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