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Additional
Info on the PEEK Polymer
PEEK™ polymer
is increasingly used for the transport and storage of semiconductors
during production. Historically, the material of choice has been
carbon fiber reinforced polypropylene. However, with increasing
specification of semiconductor wafers, it has become clear that
polypropylene carriers have met their limitation. Production is
adversely affected by wear particles, outgassing, doping of semiconductors
by the ionic extractables and poor mechanical properties of the
carrier material.
Wear particles
are produced by contact between the carrier material and other surfaces.
Independent tests by industry experts have shown that PEEK™ polymer
sheds extremely low levels of wear particles (ASTM-D1044) compared
to other thermoplastics.
Outgassing may
be defined as the emission of volatile compounds, which may subsequently
condense on wafers causing contamination. The testing standard ASTM-F1227-89
measures the Collective Volatile Condensed Material (CVCM) mass
at 68°F (20°C). Although PEEK™ polymer and polypropylene carriers
both meet SEMI specifications in this test, PEEK™ polymer has a
lower CVCM value. In addition, PEEK™ polymer wafer carriers have
a tighter tolerance and retain their dimensional stability over
a much longer service lifetime, and broader temperature range (UL
continuous service operating temperature ~ 500°F (260°C)). The excellent
mechanical properties of PEEK™ polymer over a wide temperature range
increase the use of automated transfer production systems.
Semiconductor
wafer carriers often experience aggressive chemical environments
at elevated temperatures. Over a service lifetime, materials may
be leached of ionic species which have been shown to diffuse into
the semiconductors, acting as doping agents. PEEK™ polymer has extremely
low levels of ionic extractables.
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