Plasmas can interact with surfaces in many ways.
Thin films can be deposited with various properties depending on the specific gas and process parameters. (Example: CHF3 (gas) + H2 (gas) = CFx (surface) + HF (gas)).
Plasmas can deposit thin polymer coatings through polymerization of the gases which results in a crosslinked matrix on the surface. These polymer type films can exhibit a high degree of durability and adhesion to the substrate surfaces.
Using gases which can chemically react with the surface materials, a volatile by-product can be formed which is pumped away resulting in material removal from the surface. (Example: SiO2(solid) + CF4 (gas) = SiF4 (gas) + CO2(gas))
Chemistries can be tuned such that certain films materials be preferentially removed to others.
Plasma surface activation can involve the creation of surface functional groups through the use of specific gases like oxygen which chemically reacts with the surface. The plasma can break surface bonds of polymers and replace them with reactive hydroxyl or carboxyl groups.
Surface activation can modify the surface characteristics such as wetting or adhesion resulting in greater adhesive strength and improved bonding.
Plasmas can be used to create cross-linked polymers as a result of physical alterations (ion surface bombardment) and chemical mixing of molecular chains. These new properties can be more durable than their unaltered counterparts.
Plasma ablation involves the physical removal of surface contaminants from electron and ion collisions with surfaces. Usually Noble Gases like Argon, Helium or chemical inert Nitrogen are used to breakdown weak covalent bonds or absorbed surface layers.
Contamination layers of organic materials like hydrocarbons (oils, grease, fingerprint) and other biological agents can be removed.
With sufficient RF power, the low molecular weight materials can be clean from surface by physically eroding (sputtering) them away.
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