Evaporation vacuum coating machine works

                     

Vacuum coating machine vacuum evaporation coating (referred to evaporation) is the earliest development of PVD technology, is widely used in coating technology. Although later developed sputtering and ion plating is superior in many respects than the deposition, but there are many advantages of vacuum evaporation techniques, such as equipment and technology is relatively simple and can be very pure film coating system, but also to prepare film with a specific structure and nature, are still very important in today's coating technology. In recent years, due to electron bombardment evaporation, high frequency induction evaporation and laser evaporation technique widely used in the evaporation coating techniques to make this technology more perfect.

The membranes placed in a vacuum coating chamber, by heating to evaporate the evaporation source, when the mean free path of the molecules is greater than the linear dimensions of the evaporation vacuum coating chamber, atomic and molecular vapor to escape from the rear surface of the evaporation source, rarely other molecules or atoms impact the obstacle, can be plated directly to the substrate surface, due to the low substrate temperature, it condenses thereon to form a film, in order to improve the adhesion to the substrate molecule was evaporated, the substrate is heated appropriately is necessary. For the evaporation coating smoothly, should have the vacuum evaporation process and the process of film evaporation.

Vacuum evaporation process conditions: when the mean free path of the vapor molecules of the vacuum coating indoor greater than the distance of the evaporation source and the substrate (called steaming distance), will obtain a sufficient vacuum. For this reason, increasing the mean free path of the residual gas, so as to reduce the probability of collisions with residual gas molecules of steam molecules, the vacuum coating chamber evacuated to a high vacuum is necessary.

Vacuum coating process, the requirements for the degree of vacuum is not the higher the better, because the degree of vacuum in the vacuum coating interior beyond 10-6Pa, you must bake the vacuum degassing system can be achieved. Since baking degassing can cause pollution of the substrate, thus without baking degassing under a high vacuum can be obtained when the film 10-5Pa, the quality of the film is not necessarily lower than the ultra-high vacuum film prepared poor quality, it is worth noting. Therefore, in the vacuum evaporation coating equipment, coating chamber vacuum degree of choice should be generally higher than 10-2Pa, less than 10-5Pa.