Vacuum evaporation coating principle of glass

Release time:

2023-11-23

Source:

The film material is placed in the evaporation source in the vacuum chamber. Under high vacuum conditions, the film material is evaporated by heating the evaporation source. After the atoms and molecules of the film material vapor escape from the surface of the evaporation source, and when the mean free path of the vapor molecules is larger than the linear size of the vacuum chamber, it rarely receives collisions and obstacles from other molecules or atoms, and can directly reach the surface of the plated substrate. Due to the low substrate temperature, the film material vapor particles condense on it to form a film. In order to improve the adhesion of the evaporated molecules to the substrate, it is necessary to activate the substrate by appropriate heating or ion cleaning.

Physical process of vacuum evaporation coating
The film material is placed in the evaporation source in the vacuum chamber. Under high vacuum conditions, the film material is evaporated by heating the evaporation source. After the atoms and molecules of the film material vapor escape from the surface of the evaporation source, and when the mean free path of the vapor molecules is larger than the linear size of the vacuum chamber, it rarely receives collisions and obstacles from other molecules or atoms, and can directly reach the surface of the plated substrate. Due to the low substrate temperature, the film material vapor particles condense on it to form a film. In order to improve the adhesion of the evaporated molecules to the substrate, it is necessary to activate the substrate by appropriate heating or ion cleaning.
Vacuum evaporation coating from material evaporation transport to deposition film, the physical process experienced is:
(1) using a variety of energy sources into heat, heating the film to make it evaporate or sublimation, into a certain energy (01~0.3eV) of gaseous particles (atoms, molecules or atomic groups);
(2) Leaving the surface of the membrane material, gaseous particles with a considerable velocity of motion are transported to the surface of the substrate in a substantially collision-free straight-line flight;
(3) The gaseous particles reaching the surface of the substrate agglomerate and nucleate into a solid phase film;
(4) The atoms constituting the film are rearranged or chemically bonded.
In order to make the evaporation coating smoothly, two conditions should be met: the vacuum condition during the evaporation process and the evaporation condition during the coating process.