Plasma cleaning/etching technology is a specific application of the special properties of plasma: The plasma cleaning/etching machine generates plasma by setting two electrodes in a sealed container to form an electric field. A vacuum pump is used to achieve a certain degree of vacuum. As the gas becomes thinner and thinner, the molecular distance and the free movement distance of molecules or ions also increase. As they grow longer and longer under the action of an electric field, they collide to form a plasma. These ions are highly active and their energy is sufficient to break almost all chemical bonds and cause chemical reactions on any exposed surface. Plasma of different gases has different characteristics. Chemical properties, such as oxygen plasma has high oxidizing properties, can oxidize the photoresist reaction to generate gas, so as to achieve the cleaning effect; corrosive gas plasma has good anisotropy, so that it can meet the etching Needs. Glow is emitted when plasma treatment is used, so it is called glow discharge treatment. The mechanism of plasma cleaning mainly relies on the "activation" of the active particles in the plasma to achieve the purpose of removing stains on the surface of the object. In terms of reaction mechanism, plasma cleaning usually includes the following processes: inorganic gas is excited into a plasma state; gas phase substances are adsorbed on the solid surface; adsorbed groups react with solid surface molecules to produce product molecules; product molecules resolve to form a gas phase; reaction The residue is detached from the surface. A major feature of plasma cleaning technology is that it can be processed regardless of the type of substrate to be processed. It can treat metals, semiconductors, oxides and most polymer materials, such as polypropylene, polyester, polyimide, and polyimide. Ethylene chloride, epoxy, and even polytetrafluoroethylene can be handled well, and can be used to clean the whole and part as well as complex structures. Plasma generation conditions: sufficient reaction gas and reaction pressure, the reaction product must be able to hit the surface of the cleaning object at high speed, and have sufficient energy supply. The substance produced after the reaction must be a volatile fine combination to facilitate the vacuum pump To pump it away, the capacity and speed of the pump must be large enough to quickly discharge the by-products of the reaction, and it needs to be quickly refilled with the gas required for the reaction. Corresponding to different materials, use the corresponding gas combination to form a strong etching gas-phase plasma and chemical reaction and physical impact with the body of the material surface, so that the solid material on the surface of the material body is vaporized to generate gases such as CO, CO2, H2O, etc. , So as to achieve the purpose of micro-etching.
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