Vacuum evaporation coating (hereinafter referred to as evaporation) is the earliest and widely used coating technology in PVD technology. Although the later developed sputtering and ion plating are superior to evaporation in many aspects, vacuum evaporation technology still has many advantages, such as the equipment and process are relatively simple, you can plate a very pure film layer, and you can prepare a film layer with a specific structure and properties, it is still a very important coating technology today. In recent years, due to the extensive application of electron bombardment evaporation, high-frequency induction evaporation and laser evaporation in evaporation coating technology, this technology has become more perfect.

When the average free path of evaporated molecules is greater than the linear size of the vacuum coating chamber, the atoms and molecules of the steam escape from the surface of the evaporation source, rarely hindered by the impact of other molecules or atoms, and can directly reach the surface of the plated substrate. Due to the low temperature of the substrate, they condense on it to form a film. In order to improve the adhesion between the evaporative molecules and the substrate, it is necessary to properly heat the substrate. In order to make the evaporation coating proceed smoothly, the vacuum conditions in the evaporation process and the evaporation conditions in the film making process should be available.
Vacuum conditions in the evaporation process: When the average free path of steam molecules in the vacuum coating chamber is greater than the distance between the evaporation source and the substrate (called the evaporation distance), sufficient vacuum conditions will be obtained. Therefore, it is necessary to increase the mean free path of the residual gas to reduce the probability of collision between the vapor molecules and the residual gas molecules, and to pump the vacuum coating chamber into a high vacuum.
The requirement for the vacuum degree in the vacuum coating process is not the higher the better, because when the vacuum degree in the vacuum coating chamber exceeds 10-6Pa, the vacuum system must be baked and degassed to achieve it. Because baking degassing will cause substrate pollution, 10-5Pa high vacuum film can be made without baking degassing, and the quality of the film is not necessarily worse than that of the film prepared under ultra-high vacuum, which is noteworthy. Therefore, in the evaporation pvd coating machine, the vacuum degree selected by the pvd acuum coating chamber should generally be higher than 10-2Pa and lower than 10-5Pa.
evaporation pvd coating machine is the most original pvd coating machine, the most widely used, the market share is also the highest, of course, with the continuous innovation and development of technology, new technologies continue to emerge, evaporation coating technology and equipment costs are naturally relatively low.