Cold gas plasma is a powerful tool allowing customized molecular
re-engineering of materials to impart unique surface properties,
without affecting the bulk properties. The effect of plasma on a
material is determined by the chemistry of the reactions between
the surface and the reactive species present in the process gas
employed. A multitude of gases can be used. Each gas produces a
unique plasma composition resulting in different surface properties.
Liquids may also be introduced as vapors, expanding by many orders
of magnitude the potential for unique surface alterations and coatings.
Please click here for process
examples.
Cold gas plasma modifications are achieved via a vacuum process.
The components to be treated are placed in a vacuum chamber with
air removed via a vacuum pump to base pressures on average from
35 to 100 mtorr. Process gas(es) are introduced into the chamber
and allowed to reach equilibrium, typically from 100 to 500 mtorr.
Radio-frequency energy supplied to electrodes within the chamber
excites the gas(es) into plasma. Plasma, the 4th state of matter,
is a gas comprised of modest concentrations of electrons, ions,
as well as other excited meta-stables. These excited species have
sufficient energy to rupture chemical bonds of the component (substrate).
These ruptured bonds are thermodynamically unstable and reach out
into the plasma to combine with gas fragments to normalize its energy,
thereby molecularly re-engineering the surface of the material placed
into the plasma.
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| Treatment Chamber Window. |
Plasma Treatment in Action. |
The processes are low energy and the species created have little
penetrating energy, thus the modification is limited to the surface
typically no deeper than a few molecular layers. Ultra-thin temperature
sensitive materials can be easily modified in cold gas plasma without
deteriorating the bulk properties of the material being treated.
As practiced in non-semiconductor applications, cold gas plasma
is recognized as both a worker and workplace safe clean air technology.
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Surface preparation to include removal
of organic contaminants |
  Removal
of organic contaminants such as:
 Desmear
Finger
oils
Silicone
oils
Parylene
deposits
Sizing
Solder
flux
Carbon
soot
Machining
fluids
Mold
release agents
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Plasmas containing simple non-carbon containing gases
are used to break surface layer molecular bonds leading
to an altered surface chemistry, depending on the process
gas. |
Hydrophilicity
Hemophilicity
Hydroxyl, Carboxylic, Carbonyl, Amine (1°,
2°, 3°), Vinyl, Glycidyl, and Thio functionalities
Functional sites for subsequent attachment of
cells, proteins, drugs, bio-conjugated polymers
Adhesion
enhancement
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Carbon containing gases, under the
influence of a plasma, can be deposited to create unique
surface coatings. |
Polymerized
hydrocarbon coatings
Fluoropolymer
coatings
Chemical
barrier and scratch resistant coatings
Glass-like
surfaces
Dry
lubricous surfaces |
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Barrier
coatings
Stability
of surface molecules to prevent rotation |
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can also be accomplished when introducing species in
a non-powered step to allow attachment of molecules |
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