Abstract
There is a growing trend towards more integrated, more compact, and lower-profile semiconductor packaging. Melt flow channels for encapsulation molding compounds are therefore becoming narrower and their filling characteristics are becoming important.
In this study, the authors have attempted to clarify slip phenomena in a narrow gap rectangular flow channel in the melt flow of an epoxy molding compound for encapsulation. The slip velocity was estimated by the Mooney method and measured by the flow visualization method. The equations in the Mooney method for a rectangular flow channel were newly derived. Slip velocity estimated by the Mooney method matched that measured by the flow visualization method within a range of about 30% for slit gaps of 0.21 and 0.31mm. An approximate relationship between slip velocity and shear stress was obtained and it was shown that a critical stress for slipping exists.
It was also confirmed that “wall slip” is a dominant factor for melt flow in the low shear rate zone of a narrow gap channel.
