With the development of high density packages, the space
from die edge to bond finger is shrunk and challenge comes
into being for liquid-type adhesive correspondingly due to its
bleed-out. Die attach film (DAF) as alternative has being
widely used with its good control of bleed, consistent bond
line thickness (BLT) and simplified operation. However void
at the interface between die and substrate is one of major
concerns. There are many factors contributed to void
performance including DAF material property, substrate
surface condition, die attach parameters and so on. In this
paper, the effect of transfer pressure on void performance in a
ball grid array plastic package is focused on. Simultaneously
the characteristic of DAF void and its formation/reduction
mechanism also are investigated. It was found that the DAF
voids occur at substrate/film interface with fixed location and
similar pattern. They can be reduced significantly by
enhancement of transfer pressure during molding process,
which can be explained that gap on substrate surface is filled
furthest by film under high transfer pressure.
With the development of high density packages, the spacefrom die edge to bond finger is shrunk and challenge comesinto being for liquid-type adhesive correspondingly due to itsbleed-out. Die attach film (DAF) as alternative has beingwidely used with its good control of bleed, consistent bondline thickness (BLT) and simplified operation. However voidat the interface between die and substrate is one of majorconcerns. There are many factors contributed to voidperformance including DAF material property, substratesurface condition, die attach parameters and so on. In thispaper, the effect of transfer pressure on void performance in aball grid array plastic package is focused on. Simultaneouslythe characteristic of DAF void and its formation/reductionmechanism also are investigated. It was found that the DAFvoids occur at substrate/film interface with fixed location andsimilar pattern. They can be reduced significantly byenhancement of transfer pressure during molding process,which can be explained that gap on substrate surface is filledfurthest by film under high transfer pressure.
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