How To Control The Uniformity Of Vacuum Coating

- Dec 24, 2018-

How to control the uniformity of vacuum coating


Grasp the debugging of the coating machine is the key to use the coating machine! So how do we do that?


Debugging method of vacuum coating machine


1. Vacuum extraction speed of test equipment, check air leakage and performance of vacuum pumps during the test;

2. The sealing performance of the test equipment is to check whether the pressure drop is up to the standard for 1 hour after the pressure is maintained to the limit, and to eliminate small leakage holes at the same time;

3. The product is tested and tested for other properties, such as transmission, heating, insulation, etc.;

4. If there is process guarantee, continue to make samples and test;

5. All tests shall be recorded and signed by the recorder and confirmed and signed by the user department or engineering department.


How to control the uniformity of vacuum coating


Due to the different principles of vacuum coating machine is divided into many types, just because of the need for high vacuum and has a unified name. Therefore, for vacuum coating of different principles, the factors affecting uniformity are not the same. And the concept of uniformity itself will also have different meanings with the coating scale and film composition, as described below:


Uniformity is mainly reflected in three aspects:


1. Uniformity of thickness can also be understood as roughness

On the scale of optical film (that is 1/10 wavelength as a unit, about 100A), the uniformity of vacuum coating has been quite good, roughness can be easily controlled in the visible light wavelength 1/10 range, that is to say, for the optical characteristics of multi-arc ion coating machine, vacuum coating without any obstacles. However, if it refers to the uniformity on the scale of atomic layer, that is to say, to achieve the surface leveling of 10A or even 1A is the main technical content and technical bottleneck of vacuum coating.


2. Uniformity of chemical composition


Atomic group branch is in the film, compounds because of the scale is too small and it is easy to produce uneven characteristics of SiTiO3 film, if not scientific process of sputtering coating machine, and so on the surface of the actual components not SiTiO3, and may be in proportion to the other, the plating film is not want the chemical composition of the membrane, it is also the technical content of vacuum coating.


3. Uniformity of lattice order


This determines that the film is a single crystal, polycrystalline, amorphous, vacuum coating technology is a hot issue.