Analytical Analysis on the Capillary Pressure of Underfill Flow Meniscus During the Flip-Chip Encapsulation Process

Authors

  • Fei Chong Ng School of Mechanical Engineering, Universiti Sains Malaysia, Engineering Campus, Nibong Tebal, 14300, Penang, Malaysia
  • Lun Hao Tung School of Mechanical Engineering, Universiti Sains Malaysia, Engineering Campus, Nibong Tebal, 14300, Penang, Malaysia
  • Mohamad Aizat Abas School of Mechanical Engineering, Universiti Sains Malaysia, Engineering Campus, Nibong Tebal, 14300, Penang, Malaysia

DOI:

https://doi.org/10.37934/arfmts.94.2.174183

Keywords:

Bump pitch, electronic packaging, capillary pressure, contact angle, flip-chip, underfill encapsulation process

Abstract

In the conventional flip-chip underfill encapsulation process, the underfill fluid is driven into the gap beneath the chip and substrate through capillary action. Particularly, the capillary pressure of the flow front determined the strength of overall capillary flow advancement through the bump array, hence the filling time and subsequently the manufacturing productivity. This paper analytically studied the capillary pressure of the flow front. Accordingly, the variation effects of bump contact angle and bump pitch on the flow front capillary pressure were presented. It was found that the variation trend of capillary pressure along the flow displacement between the region confined by two adjacent bumps is sinusoidal. The magnitude of capillary pressure is positive near bump entrant and acting along the flow direction before the capillary pressure gradually decreasing to oppose the flow advancement. The increasing of contact angle shifted the capillary pressure trend leftward with the peak being lowered, whereas the magnitude of capillary pressure decreases with the increases in bump pitch. Additionally, by studying the capillary pressure of flow meniscus, a new dynamic-based contact line jump criterion was proposed by considered the peak capillary pressure along the underfill advancement. These findings are practically useful for the design optimization of flip-chip package to promote the longevity of electronic package and reduce electronic wastes.

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Author Biographies

Fei Chong Ng, School of Mechanical Engineering, Universiti Sains Malaysia, Engineering Campus, Nibong Tebal, 14300, Penang, Malaysia

feichong_92@live.com

Lun Hao Tung, School of Mechanical Engineering, Universiti Sains Malaysia, Engineering Campus, Nibong Tebal, 14300, Penang, Malaysia

francistlh1994@gmail.com

Mohamad Aizat Abas, School of Mechanical Engineering, Universiti Sains Malaysia, Engineering Campus, Nibong Tebal, 14300, Penang, Malaysia

aizatabas@usm.my

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Published

2022-04-27

How to Cite

Fei Chong Ng, Lun Hao Tung, & Mohamad Aizat Abas. (2022). Analytical Analysis on the Capillary Pressure of Underfill Flow Meniscus During the Flip-Chip Encapsulation Process. Journal of Advanced Research in Fluid Mechanics and Thermal Sciences, 94(2), 174–183. https://doi.org/10.37934/arfmts.94.2.174183

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