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Numerical investigation on rheology models during encapsulation of moulded underfill (MUF) for flip-chip package

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Abstract

This paper presents a numerical analysis of different rheology models during the encapsulation of moulded underfill (MUF) for flip-chip package. Robust computational fluid dynamics of finite volume analysis software; ANSYS FLUENT Workbench 14.5 was utilised in three-dimensional. A remarkable analysis was carried out by considering three distinctions among rheology models, namely Power Law, Cross, and Castro-Macosko. Nevertheless, a unique function has been written for the Castro–Macosko model since it considers the curing effect using user-defined functions. The volume of fluid technique was utilised to track the flow front of epoxy moulding compound (EMC). Beforehand, the flow visualization for the tray cavity has been verified by both experiment and simulation qualitatively, and it has been found to be in good agreement. It also conformed to the rheological properties, i.e., viscosity and shear rate. For MUF encapsulation, the 3D views of the melt front profile during encapsulation were presented. In addition, the viscosity-shear rate and void formation versus rows of multi-flip chips for all models were plotted and discussed. The numerical results have shown that the best rheology model for EMC during encapsulation was the Castro-Macosko model with consideration of curing effect. It was clearly found that the retardation flow occurred since the conversion of EMC took place, i.e., the curing effect. The present numerical analysis is expected to grant a good understanding of epoxy behaviour for engineers and designers in the electronic packaging industry.

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Acknowledgements

The authors would like to acknowledge Universiti Sains Malaysia, Ministry of Education (MOE) of the Malaysian government for providing the facilities and financial assistance under Skim Geran Penyelidikan Fundamental (FRGS) accounts FRGS/1/2019/TK05/USM/02/3 and Intel Technology Sdn. Bhd. (Kulim) for the technical and facilities support for this research.

Funding

This research was funded by a grant Skim Geran Penyelidikan Fundamental (FRGS) under accounts FRGS/1/2019/TK05/USM/02/3 by the Ministry of Education (MOE) of the Malaysian government.

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Authors and Affiliations

  1. School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, Engineering Campus, 14300, Nibong Tebal, Penang, Malaysia

    Muhammad Afiq Azmi, Raa Khimi Shuib, Zulkifli Mohamad Ariff & Muhammad Khalil Abdullah

  2. School of Mechanical Engineering, Universiti Sains Malaysia, Engineering Campus, 14300, Nibong Tebal, Penang, Malaysia

    Mohd Zulkifly Abdullah

  3. Intel Technology Sdn. Bhd, Kulim Industrial Technology Park, Kulim, Kedah, Malaysia

    Wei Keat Loh, Renn Chan Ooi & Chun Keang Ooi

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  1. Muhammad Afiq Azmi
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Correspondence to Muhammad Khalil Abdullah.

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Azmi, M.A., Abdullah, M.Z., Shuib, R.K. et al. Numerical investigation on rheology models during encapsulation of moulded underfill (MUF) for flip-chip package. Polym. Bull. 81, 2385–2406 (2024). https://doi.org/10.1007/s00289-023-04805-6

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