In a message dated 5/27/99 8:59:20 PM Pacific Daylight Time,
[log in to unmask] writes:
> Thank you for the information. Have you heard of hollow fiber and any spec
> or standard for that?
Hi there,
While I'm no laminate guru, my "doggie" did turn-up these two leads:
Hollow Fibers in Woven Laminates
A. Shukla, T. Dishongh, M. Pecht, and D. Jennings
Printed Circuit Fabrication, Vol. 20, No. 1, January 1997
------------------------------------------------------------------------
ABSTRACT:
Electronic packaging substrates with fine-line circuitry, such as those used
in laminated multichip modules (MCM-L) and plastic ball grid arrays (PBGAs),
are generally fabricated with layers of copper clad composite laminates. The
conducting copper provides electrical interconnections and power distribution
for the system, while composite laminates furnish mechanical support for the
structure along with insulative resistance.
Most laminates are comprised of several plys of glass fabrics embedded in a
polymeric resin, where the fabric acts as a structural reinforcement by
offsetting the resin's inherent mechanical and thermomechanical weaknesses. A
popular fabric fiber material used in the electronics industry for laminate
reinforcement is E-glass due to cost high strength, water resistance, and
bond stability with resins.
******************************************************************************
**************
Hollow Fibres in PCB, MCM-L and PBGA Laminates May Induce Reliability
Degradation
A. Shukla, M. Pecht, J. Jordan, K. Rogers, and D. Jennings
Circuit World, Vol. 23, No. 2, 1997
------------------------------------------------------------------------
ABSTRACT:
The presence of hollow fibres in laminates used in printed circuit boards,
multichip module laminated substrates and plastic ball grid arrays has a
potentially significant impact on reliability. Hollow fibres are vacuous
glass filaments in E-glass laminate reinforcements and are seen as a
reliability problem since they can provide paths for failure mechanisms such
as conductive filament formation. This paper discusses the manufacture of
woven fabric laminates and the cause of hollow fibres Experiments conducted
to assess the occurrence of hollow fibres in laminates are then presented
long with the key reliability issue.
So try and find some way to get your hands on those articles and you may find
out what you need....
-Steve Gregory-
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