The evaporation pvd coating machine
mainly consists of a vacuum coating chamber and a vacuum system. The vacuum chamber contains an evaporation source (i.e. evaporation heater), substrate and substrate holder, electrode rod, power supply, crucible, substrate heater, exhaust system, etc. .
The coating material is placed in the evaporation source in the vacuum chamber. Under high vacuum conditions, it is evaporated by heating the evaporation source. When the mean free path of the vapor molecules is greater than the linear size of the vacuum chamber, the atoms and molecules of the vapor in the film material evaporate from After escaping from the source surface, it is rarely collided and hindered by other molecules or atoms, and can directly reach the surface of the substrate to be plated. Due to the low temperature of the substrate, the vapor particles of the film material condense on it to form a film.
In order to improve the adhesion between the evaporated molecules and the substrate, the substrate can be activated by appropriate heating or ion cleaning. Vacuum evaporation coating goes through the following physical processes from material evaporation, transportation to deposition and film formation:
1. Use various methods to convert other forms of energy into thermal energy, heat the film material to evaporate or sublimate it, and turn it into gaseous particles (atoms, molecules or atomic groups) with a certain energy (0.1~0.3eV):
2. The gaseous particles leave the surface of the membrane and are transported to the surface of the substrate in a straight line with considerable movement speed and basically without collision;
3. The gaseous particles that reach the surface of the substrate condense and nucleate and grow into a solid film;
4. The atoms that make up the film are rearranged or chemically bonded.