Introduction of Vacuum Evaporation Coating Technology

The vacuum evaporation coating technology of vacuum coating machine manufacturers includes resistance evaporation coating, electron beam evaporation coating, laser beam evaporation coating, high frequency induction heating evaporation coating, etc. The following table lists the characteristics of several evaporative coating technologies.

1. Resistance evaporation plating: The resistance evaporation source is used to evaporate low melting point materials, such as gold, silver, zinc sulfide, magnesium fluoride, chromium trioxide, etc. Resistance evaporation sources are generally made of tungsten, molybdenum and tantalum.

2. Electron beam evaporation plating: After the film material is vaporized and evaporated by electron beam heating, it is an important heating method in vacuum evaporation technology to condense and form a film on the surface of the substrate. There are many types of such devices. With the wide application of thin film technology, not only the requirements for the types of membranes are various, but also the requirements for the quality of the membranes are more stringent. Resistance evaporation can no longer meet the needs of evaporation of some metals and non-metals. The electron beam heat source can obtain a much larger energy density than the resistance heat source, and the value can reach 104-109w/cm2, so the film can be heated to 3000-6000c. This provides a better heat source for evaporating refractory metals and non-metallic materials such as tungsten, molybdenum, germanium, SiO2, AI2O3, etc. Moreover, since the material to be evaporated is placed in a water-cooled crucible, the evaporation of the container material and the reaction between the container material and the film material can be avoided, which is extremely important for improving the purity of the film. In addition, heat can be directly added to the surface of the film material, so the thermal efficiency is high, and the heat conduction and heat radiation losses are small.

3. High-frequency induction heating evaporation plating: The metal is heated to the evaporation temperature using the principle of induction heating. Place the crucible containing the film material in the center of the spiral coil (non-contact), and pass a high-frequency current through the coil, which can make the metal film material generate current to heat itself up until it evaporates.

The characteristics of the induction heating evaporation source: 1) The evaporation rate is large 2) The temperature of the evaporation source is uniform and stable, and it is not easy to produce aluminum drop splash phenomenon 3) The evaporation source is charged at one time, no wire feeding mechanism is required, the temperature control is relatively easy, and the operation is simple 4) For the film Material purity requirements are slightly wider.

4. Arc heating evaporation plating: A heating method similar to the electron beam heating method is the arc discharge heating method. It also has the characteristics of avoiding the contamination of resistance heating materials or crucible materials, and the heating temperature is high, especially suitable for the evaporation of refractory metals, graphite, etc. with high melting point and certain conductivity. At the same time, the equipment used in this method is simpler than that of the electron beam heating device, so it is a relatively inexpensive evaporation device.

5. Laser beam evaporation plating: The method of using high power density pulsed laser to evaporate the material to form a thin film is generally called laser evaporation