Title :
Underfill flow as viscous flow between parallel plates driven by capillary action
Author :
Schwiebert, Matthew K. ; Leong, William H.
Author_Institution :
Electron. Assembly Dev. Center, Hewlett-Packard Co., Palo Alto, CA, USA
fDate :
4/1/1996 12:00:00 AM
Abstract :
Epoxy underfill is often required to enhance the reliability of flip-chip interconnects. This study evaluates the flow of typical epoxy underfill materials between parallel plates driven by capillary action. An exact model was developed to understand the functional relationship between flow distance, flow time, separation distance, surface tension, and viscosity for quasisteady laminar flow between parallel plates. The model was verified experimentally with a typical underfill material. The measured values of flow distance agreed well with the exact model. A new material parameter, the coefficient of planar penetrance, is introduced. This parameter measures the penetrating power of a liquid between parallel plates driven by capillary action. The effectiveness of gravity and vacuum as flow rate enhancements is explored
Keywords :
capillarity; flip-chip devices; integrated circuit interconnections; integrated circuit reliability; laminar flow; reflow soldering; surface tension; viscosity; capillary action; flip-chip interconnects; flow distance; flow rate enhancements; flow time; material parameter; parallel plates; planar penetrance; quasisteady laminar flow; reliability; separation distance; surface tension; underfill flow; viscosity; viscous flow; Differential equations; Fluid flow measurement; Gravity; Laplace equations; Lead; Materials reliability; Partial differential equations; Power measurement; Surface tension; Viscosity;
Journal_Title :
Components, Packaging, and Manufacturing Technology, Part C, IEEE Transactions on
DOI :
10.1109/3476.507149
