What is Vacuum Coating?
Vacuum coating is an advanced technology that deposits functional thin films on the surface of substrates through physical or chemical methods in a vacuum environment. Its core value lies in high purity, high precision and environmental protection, and is widely used in optics, electronics, tools, new energy and other fields.
Does the vacuum coating system need to be equipped with inlet filters?
Firstly, let us learn what are the common pollutants in vacuum coating. For example, particles, dust, oil vapor, water vapor, etc. These pollutants entering the coating chamber will cause the deposition rate to decrease, the film layer to be uneven, and even damage the equipment.
The situation where vacuum coating does require inlet filters
- During the coating process, the target material splashes particles.
- The purity requirement of the film layer is high, especially in the fields of optics and semiconductors.
- There are corrosive gases (easily produced in reactive sputtering). In this case, the filter is installed mainly to protect the vacuum pump.
The situation where vacuum coating does not require inlet filters
- Many vacuum coating service providers use a completely oil-free high vacuum system (like molecular pump + ion pump), and the working environment is clean. Therefore, there is no need for inlet filters, or even exhaust filters.
- There is another situation where inlet filters are not required, that is, the purity requirement of the film layer is not high, such as for some decorative coating.
Others about oil diffusion pump
- If an oil pump or oil diffusion pump is used, exhaust filter must be installed.
- Polymer filter element is not resistant to high temperature of diffusion pump
- When using an oil diffusion pump, the pump oil may flow back and contaminate the coating chamber. Therefore, it requires a cold trap or oil baffle to prevent the accident.
In conclusion, whether the vacuum coating system need inlet filters depends on process requirements, system design and contamination risk.
Post time: Apr-19-2025
