During the coating process of the pvd coating machine, a power supply must be applied. The base materials for plating are different, the processes are different, the equipment configurations are also different, and the power supplies used are also different. Below, the editor of Huicheng Vacuum will introduce some details to you. Common power supplies:

arc power supply
       The realization of target evaporation and ionization in arc ion plating must rely on the arc power supply to provide energy. During the actual coating process, the power supply must be able to automatically detect the arc extinguishing phenomenon and automatically start the arc to ensure the continuity of the coating process and the uniformity of the film layer. In addition, the arc stabilizing performance of the arc power supply, especially the minimum arc stabilizing current, has a great impact on the consistency, efficiency and smoothness of the film layer. A multi-arc ion coating machine is equipped with as few as a few arc power supplies, as many as a dozen or even dozens of arc power supplies. Stable and reliable operation is crucial to the performance of the entire equipment. The arc power supply has developed from the traditional power supply type to the current high-frequency inverter type through the use of thyristor technology. Compared with arc power supplies made by traditional electromagnetic and thyristor technology, high-frequency inverter arc power supplies mainly have the following characteristics:
       1. The size is reduced to only a fraction of the old power supply; the corresponding weight of the power supply is also only a fraction to a dozen of that of the traditional power supply.
       2. The power supply efficiency is significantly improved, about 20%∽30% higher than the efficiency of the old power supply.
       3. It is easy to operate, has high current adjustment accuracy and good flow stabilization performance, which is conducive to precise control of film thickness and ensuring the repeatability of film thickness.
       4. The ripple of the arc power supply using high-frequency inverter mode is smaller, and its response speed is much higher than that of the old power supply. Under the same arc source and working conditions, the use of high-frequency inverter arc power supply is conducive to improving the stability of the arc. properties and reduce the number of arc extinguishments.

  Magnetron sputtering power supply
       Judging from the output waveform, with the development of magnetron sputtering technology itself, it has experienced direct current, unipolar pulse, symmetric bipolar pulse (medium frequency magnetron sputtering power supply) and bipolar pulse (asymmetric mid-frequency magnetron sputtering power supply). radio source) in several ways. At present, new magnetron sputtering power supplies are basically manufactured using high-frequency inverter switching power supply technology, and medium-frequency magnetron sputtering power supplies have become the preferred power supply for new magnetron sputtering equipment. In order to accurately control the film thickness, the magnetron sputtering power supply must work stably and have good constant characteristics. At present, the constant current method is mainly used, and the constant power method is also used, and the constant voltage method is rarely used. In addition, a significant advantage of magnetron sputtering coating technology is that the film layer is dense and the finish is good. To realize this advantage, it is necessary to strictly limit the number of ignitions on the target surface and the energy of each ignition during the magnetron sputtering process, and minimize the number of macroscopic target particles caused by the ignition moment. They will reduce the density and density of the film layer. The smoothness may cause the film to fall off in severe cases.


Bias power supply
       Bias power supplies are used in both multi-arc ion and magnetron sputtering coating technologies. Just because the ionization rate of magnetron sputtering is much lower than that of multi-arc ion plating, the power of the required bias power supply is smaller. Currently, many equipment are equipped with both magnetron sputtering targets and multi-arc targets. When selecting the power of the bias power supply, it must be determined based on the working requirements of multiple targets. Early bias voltages were mainly DC bias power supplies using thyristor technology. Nowadays, they are mostly unipolar, DC superimposed pulse and bipolar pulse bias power supplies manufactured using high-frequency inverter technology. The bias power supply is mainly used to apply bias on the workpiece to be coated during glow cleaning, ion bombardment and film deposition in the multi-arc ion and magnetron sputtering coating processes. During glow cleaning, it produces glow; In ion bombardment, it is used to accelerate ions and increase the energy of ion bombardment on the surface of the workpiece to achieve the purpose of sputtering cleaning effect and improving the bonding force of the film layer. During film deposition, it is also used to increase ion energy to promote and improve film growth. , will also improve the film-base bonding force. The following are bias power supplies with several common waveforms:

Unipolar pulse bias power supply
       main feature
       1. High-frequency unipolar pulse bias is applied to the workpiece. Compared with DC bias, due to the voltage interruption gap, it can effectively reduce the number of flashes and protect the surface of the workpiece.
       2. During the pulse gap, the charge accumulated on the surface of the workpiece can be neutralized, thereby reducing sparking caused by surface charge accumulation.
       3. The rapid shutdown capability in high-frequency inverter technology can effectively reduce the energy released by each spark, and can significantly reduce the degree of damage to the workpiece surface even when sparks occur.
       4. The energy of ions deposited to the workpiece surface during the pulse gap is very low.
       5. The film forming speed and quality can be improved and controlled by adjusting the frequency and duty cycle.

DC superimposed pulse bias power supply
        main feature
       1. It has all the characteristics of unipolar pulse bias power supply.
       2. In DC and DC superimposed pulse mode, the problem of low ion energy between unipolar pulse gaps is eliminated.

Bipolar pulse bias power supply
       main feature
       1. The function of the negative pulse is the same as that of the unipolar pulse bias power supply. The function of the positive pulse is mainly to attract electrons in the plasma to neutralize the accumulation of positive charges on the surface of the workpiece. Because the mass of electrons is much smaller than that of ions, it is easy to accelerate, so the amplitude of the positive pulse is much smaller than the amplitude of the negative pulse, usually 10 to 100V. The current integrals of the positive and negative pulses should be equal. Therefore, the power of the positive power supply is much smaller than the power of the negative power supply.
       2. When the positive supply voltage is zero, the bipolar pulse bias becomes a unipolar pulse bias.