Vacuum evaporation coating is to use resistance heating or electron beam and laser bombardment to heat the material to be evaporated to a certain temperature in an environment with a vacuum degree of not less than 10-2Pa, so that the thermal vibration energy of molecules or atoms in the material exceeds the surface The binding energy causes a large number of molecules or atoms to evaporate or sublimate, and directly deposit on the substrate to form a thin film.
The most commonly used method for vacuum evaporation coating is resistance heating, which has the advantages of simple structure of the heating source, low cost and convenient operation. The disadvantage is that it is not suitable for refractory metals and high temperature resistant dielectric materials.
Ion sputtering coating uses the high-speed movement of positive ions generated by gas discharge to bombard the target as the cathode under the action of an electric field, causing the atoms or molecules in the target to escape and precipitate on the surface of the plated workpiece to form the required film. .
Sputtering technology is different from vacuum evaporation technology. "Sputtering" refers to the phenomenon in which charged particles bombard a solid surface (target), causing solid atoms or molecules to be ejected from the surface. Most of the ejected particles are in the atomic state, often called sputter atoms. The sputtering particles used to bombard the target can be electrons, ions or neutral particles. Because ions are easy to accelerate to obtain the required kinetic energy under an electric field, ions are mostly used as bombardment particles. Sputtered ions all originate from gas discharge.
Different sputtering technologies use different discharge methods. DC diode sputtering uses DC discharge; tripole sputtering uses discharge supported by a hot cathode; radio frequency sputtering uses radio frequency discharge; magnetron sputtering uses discharge controlled by a ring magnetic field.
Sputtering coating has many advantages over vacuum evaporation coating. For example, any substance can be sputtered, especially elements and compounds with high melting point and low vapor pressure. The adhesion between the sputtered film and the substrate is good; the film density is high; the film thickness can be controlled and the repeatability is good, etc. The disadvantage is that the equipment is relatively complex and requires high-voltage equipment.
Of course, the advantages of the ion plating method that combines evaporation and sputtering are that it has extremely strong adhesion between the film and the substrate, has a high deposition rate, and can produce high-performance films for use in electronic devices. Metallurgical processing and decorative supplies industry.
