Plasma, like solid, liquid or gas, is a state of matter, also called the fourth state of matter. Applying enough energy to the gas to ionize it will turn it into a plasma state. The "active" components of plasma include: ions, electrons, active groups, excited nuclides (metastable state), photons, etc. The plasma surface treatment instrument uses the properties of these active components to treat the sample surface, thereby achieving the purpose of cleaning, modification, photoresist ashing, etc.

The structure of the plasma cleaning machine is mainly divided into three major parts, the control unit, the vacuum chamber and the vacuum pumps.

The advantages of plasma cleaning are as follows:

I) The cleaning object is dry after plasma cleaning and can be sent to the next process without further drying. It can improve the processing efficiency of the entire process line;

2) Plasma cleaning allows users to stay away from the harm of harmful solvents to the human body, and also avoids the problem of easy damage to the cleaning object in wet cleaning;

3) Avoid using ODS harmful solvents such as trichloroethane, so that no harmful pollutants will be produced after cleaning, so this cleaning method is an environmentally friendly green cleaning method. This is becoming increasingly important as the world pays close attention to environmental protection;

4) Plasma generated by high frequencies in the radio wave range is different from direct light such as lasers. Plasma is not very directional, which allows it to penetrate into the tiny holes and recesses of an object to complete the cleaning task, so there is no need to consider the shape of the object being cleaned too much. Moreover, the cleaning effect on these difficult-to-clean areas is similar to or even better than that of Freon cleaning;

5) Using plasma cleaning can greatly improve cleaning efficiency. The entire cleaning process can be completed within a few minutes, so it has the characteristics of high yield;

6) The vacuum degree that needs to be controlled for plasma cleaning is about 100Pa, and this cleaning condition is easy to achieve. Therefore, the equipment cost of this device is not high, and the cleaning process does not require the use of expensive organic solvents, which makes the overall cost lower than the traditional wet cleaning process;

7) Plasma cleaning avoids the transportation, storage, and discharge of cleaning fluids, so the production site is easy to keep clean and hygienic;

8) Plasma cleaning can be used regardless of the object of treatment. It can treat a variety of materials, whether it is metal, semiconductor, oxide, or polymer materials (such as polypropylene, polyvinyl chloride, polytetrafluoroethylene, polyimide, polyester, epoxy resin and other polymers). Therefore, it is particularly suitable for heat-resistant and solvent-resistant materials. Moreover, the overall, partial or complex structure of the material can be selectively cleaned;

9) While completing the cleaning and decontamination, the surface properties of the material itself can also be improved. For example, improving the wetting properties of the surface and improving the adhesion of the film are very important in many applications.