Publication date: 30 January 2026
Source: Journal of Metastable and Nanocrystalline Materials Vol. 43
Author(s): Rilwan Kayode Apalowo, Alfred Kareem, Ebenezer Ikudehinbu, David Somefun, Gift Ukpoweh, Emmanuel Kehinde, Elijah Oyeleke
This study investigated the influence of nanoparticle material type and weight percentage on the flow behaviour of underfill encapsulation in Ball Grid Array (BGA) assemblies. As BGA packages are increasingly used in high-density and high-performance electronic devices, ensuring reliable solder joint encapsulation becomes critical. While nanoparticle-reinforced underfills enhance thermal and mechanical performance, they also introduce complexities in flow behaviour due to changes in viscosity and particle–fluid interactions. To address this, a multiphase numerical model was developed using the Finite Volume Method (FVM) and the Discrete Phase Model (DPM) in ANSYS Fluent to simulate the transient flow of underfill resin reinforced with Al₂O₃, SiO₂, and TiO₂ nanoparticles at varying weight percentages (5%, 10%, 15%, and 20%). The simulation captured the progression of fluid fill at intervals (25%, 50%, 75%, 95%) and measured total flow time. Results revealed Al₂O₃-based underfill consistently achieved faster flow, with the shortest 95% fill time recorded at 69.84 seconds for a 17.16% weight load concentration, while SiO₂-based underfill had the slowest flow, with times exceeding 74 seconds at 20% loading. These differences were attributed to variations in nanoparticle density and dispersion behaviour. A Random Forest regression model trained on simulation data further confirmed that nanoparticle type and concentration were the most significant predictors of flow time. These findings demonstrate that optimal nanoparticle selection can balance mechanical reinforcement with manufacturability. The results offer practical insights for electronics manufacturers aiming to improve process throughput and reliability in advanced packaging by selecting suitable nanoparticle-enhanced underfill formulations.Keywords: Underfill encapsulation, Nanoparticle reinforcement, Finite Volume Method, Discrete Phase Model, Artificial Neural Network.
[1] R.K. Apalowo, M.A. Abas, M.A.F.M. Mukhtar, and M.R. Ramli, Investigation of the Impacts of Solder Alloy Composition and Temperature Profile on Fatigue Life of Ball Grid Array Solder Joints Under Accelerated Thermal Cycling, Journal of Electronic Packaging, 147(1), 2025a.
DOI: 10.1115/1.4065805
[2] R.K. Apalowo, A. Abas, M.R. Salim, M.F.M. Sharif, and C.S. Kok, Investigating the impacts of heat sink design parameters on heat dissipation performance of semiconductor packages, International Journal of Thermal Sciences, 208, 109490, 2025b.
[3] K.S. Ng, and Z. Abas, Review of underfill flow and filler behavior in advanced electronic packaging, IEEE Access, 10, 35104–35118, 2022.
[4] J. Liang, Modeling and simulation of underfill flow in flip-chip assemblies, Journal of Electronic Packaging, 134(2), 020901, 2012.
[5] M. Tamil, A. Arulmurugan, and V. Vimalraj, Influence of underfill encapsulants on the reliability of flip-chip solder joints, Microelectronics International, 29(1), 21–27, 2012.
[6] W. Chen, C. Zhao, and X. Liu, Artificial neural networks for material property prediction: A review, Materials Today Communications, 26, 102155, 2021.
[7] R.K. Apalowo, A. Abas, Z. Bachok, M.F.M. Sharif, F.C. Ani, M.R. Ramli, and M.A.F. bin Muhamed Mukhtar, Investigation of hygrothermally induced failures in multilayer ceramic capacitors during thermal reflow process, Microelectronics Reliability, 146, 115028, 2023.
[8] R.K. Apalowo, M.A. Abas, F. Che Ani, M.A.F. Muhamed Mukhtar, and M.R. Ramli, Thermal fatigue life prediction and intermetallic compound behaviour of SAC305 BGA solder joints subject to accelerated thermal cycling test, Soldering and Surface Mount Technology, 36(3), 154–164, 2024.
[9] C. Wang, J. Han, and X. Zhang, Nanoparticle reinforced polymer composites for electronic applications: A review, Polymer-Plastics Technology and Engineering, 56(13), 1350–1364, 2019.
[10] Y. Chen, P. Renner, and H. Liang, Dispersion of nanoparticles in lubricating oil: A critical review, Lubricants, 7(1), 7, 2019.
[11] M. Stencel, R. Świercz, and M. Ostrowski, Optimization of underfill dispensing parameters in BGA assemblies using machine learning, Sensors, 23(6), 3112, 2023.
[12] M. Venkatesh, K.N. Seetharamu, I. Abdul Azid, P.A. Aswatha Narayana, and G. Abdul Quadir, Numerical simulation of underfill encapsulation process based on characteristic split method, Microelectronics Reliability, 46(9–11), 1717–1722, 2006.
DOI: 10.1002/nme.1704
[13] F.C. Ng, A. Abas, and M.Z. Abdullah, Effect of solder bump shapes on underfill flow in flip-chip encapsulation using analytical, numerical and PIV experimental approaches, Microelectronics Reliability, 81, 41–63, 2018.
[14] J. C., T. J., J. K., S. Z., J. X., and Q. M., Lucas-Washburn equation-based modeling of capillary-driven flow in porous systems, Langmuir, 31(35), 9721–9730, 2021.
[15] X. Chen, S. He, K.W. Paik, Y.H. Wong, and S. Zhang, Machine learning-driven design and optimization of electronic packaging: applications and future developments, Journal of Materials Informatics, 5, 47, 2025.
DOI: 10.20517/jmi.2025.26
[16] Y. LeCun, Y. Bengio, and G. Hinton, Deep learning, Nature, 521(7553), 436–444, 2015.
DOI: 10.1038/nature14539