In this case, plasma treatment can produce the following effects:
1, ashing surface organic layer
Pollutants partially evaporate under vacuum and instantaneous high temperature, and the pollutants are crushed by high-energy ions and taken away by vacuum.
Ultraviolet radiation destroys pollutants. Since plasma treatment can only penetrate a few nanometers per second, the pollution layer should not be too thick. Fingerprints are also applicable.
2, oxide removal
This treatment includes the use of hydrogen or a mixture of hydrogen and argon. Sometimes a two-step process is used. The first step is to oxidize the surface with oxygen for 5 minutes, and the second step is to remove the oxide layer with a mixture of hydrogen and argon. It can also be treated with several gases at the same time.
Step 3 weld
Generally speaking, printed circuit boards should be chemically treated before welding. After welding, these chemicals must be removed by plasma, otherwise it will cause corrosion and other problems.
Extended data
The device of plasma cleaning/etching machine is to set two electrodes in a sealed container to form an electric field, and use a vacuum pump to achieve a certain degree of vacuum. As the gas becomes thinner and thinner, the molecular spacing and the free movement distance of molecules or ions become longer and longer.
Under the action of electric field, they collide to form plasma. These ions are highly active, and their energy is enough to break almost all chemical bonds and cause chemical reactions on any exposed surface. Plasma of different gases has different chemical properties. For example, the plasma of oxygen is highly oxidizing, which can oxidize the photoresist to generate gas, thus achieving the cleaning effect. The plasma of corrosive gas has good anisotropy and can meet the requirements of etching.
When plasma treatment is used, it will emit glow, so it is called glow discharge treatment.
The biggest feature of plasma cleaning technology is that it can be used to treat metals, semiconductors, oxides and most polymer materials, such as polypropylene, polyester, polyimide, polyvinyl chloride, epoxy resin and even polytetrafluoroethylene, regardless of the type of substrate to be treated, and can be used to clean whole, local and complex structures.
Baidu Encyclopedia-plasma cleaning machine