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 Sifren® 46 is suggested for the use in plasma, ion beam or sputter etching in
semiconductor devices manufacturing.
Particularly outstanding results have been observed in plasma dielectric etching
with Xe and Ar as carrier gas and dilutants. In plasma dielectric etching
it is important to control the plasma chemistries in order to balance etching
and deposition species. C:F ratio in C4F6 molecule is high enough to control
the amount of polymer on the chamber surface and wafer surface with
respect to F etching radicals so achieving superior results over other gases to
produce vertical profile. More important, its intrinsic characteristics allow
high selectivity to substrate or photoresist and wider process window compared
to C4F8. This behaviour is particularly beneficial to address the need
for sub 0.25 µm requirements. Ar is being used as a carrier gas but nitride
selectivity results a decreasing function for Ar. On the opposite side, Xe
increases selectivity in such a way the mixtures Ar/Xe are a good compromise.
Normalised global warming emissions result in a reduction greater than 80%
compared to a typical C3F8 based process emissions.
Use Conditions
Around 20°C Sifren® 46 is a stable gas and is compatible with the most
carbon- or stainless-steel types. The chemically behaviour in presence of
other metals e.g. copper, tin, brass, zinc it is not completely studied. In
contact with magnesium or alloys with high magnesium (> 2%) content,
reactions are possible, contact must be avoided. The compatibility with
plastics and elastomers is depends on the temperature employed and additional
additives in the plastics materials. Fluoro-rubbers, PVC and Nylon are
suitable plastics for Sifren® 46. Material compatibility tests with Sifren® 46
are recommended.
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Plasma etching
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