The evaporation system of the pvd coating machine mainly refers to the part of the film forming device. There are many film forming devices in the coating machine, including resistance heating, electron gun evaporation, magnetron sputtering, radio frequency sputtering, ion plating and other methods. I will discuss resistance heating and electron gun evaporation. Two methods are introduced, because these two methods are used by me a lot.

       Electron gun evaporation is the most widely used evaporation method so far. It can evaporate any kind of coating material. Its working method is: put the coating material in the crucible, make the evaporation source into a filament shape, and use a special control. Cabinet, apply a strong current and high voltage to the filament, because the material of the filament is tungsten, so it will heat up, and finally will emit electrons, and then use a certain magnetic field to gather it into a certain shape, and pull it to the crucible, so that An electron beam is formed. Because the temperature of the electron beam is very high, it can melt any coated medicinal material. When the coated medicinal material is melted by the electron beam (some materials are directly sublimated), the molecules (atoms or ions) of the medicinal material move in a straight line in a vacuum. , and then when it encounters the substrate, it condenses and grows in this way to form a thin film! The most commonly used ones are the electron beam deflection angle of 270 degrees, or the e-line electron gun with an e-type trajectory, or the c-type electron gun with an electron beam deflection angle of 180 degrees and a c-type trajectory.
       The biggest advantage of electron beam evaporation is that the beam spot of the electron beam can be adjusted at will, and one gun can be used for multiple purposes. . Good mechanical strength.
       The sputtering method is to bombard the surface of the target with high-speed positive ions, and through the transmission of kinetic energy, the molecules (atoms) of the target have enough energy to escape from the surface of the target and condense to form a thin film on the surface of the product.
       The film prepared by sputtering has strong adhesion and high purity, and can sputter a variety of materials with different components at the same time, but it has high requirements on the target material and cannot save resources like an electron gun.
       At present, magnetron sputtering is the most widely used. Magnetron sputtering refers to applying a strong electric field parallel to the surface of the cathode to confine electrons near the surface of the cathode target to improve the ionization efficiency. It is the easiest one to operate, so it is very widely used.