Several power supplies commonly used in vacuum coating equipment

During the coating process of the vacuum coating machine, the power supply must be applied. The substrates of the coating are different, the process is different, the equipment configuration is also different, and the power supply used is also different. The following Dingyi Vacuum Technology will introduce several models in detail for you. Common power sources:

         arc power supply
         The realization of target evaporation and ionization in arc ion coating must rely on the energy provided by the arc power supply. In 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 stabilization performance of the arc power supply, especially the minimum arc stabilization current, has a great influence on the consistency, efficiency and smoothness of the film layer. A multi-arc ion coating machine is equipped with arc power supplies ranging from a few to as many as a dozen or even dozens. Stable and reliable work 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 the arc power source made by the traditional electromagnetic type and thyristor technology, the high-frequency inverter arc power source mainly has the following characteristics:
       1. The size is reduced, which is only a fraction of the old power supply; the corresponding weight is only a fraction to one tenth of the traditional power supply.
       2. The efficiency of the power supply is significantly improved, which is about 20%∽30% higher than that of the old power supply.
       3. Easy to operate, high accuracy of current regulation, good steady current performance, which is conducive to precise control of film thickness and repeatability of film thickness.
       4. The arc power supply using high-frequency inverter mode has small ripple, and its response speed is much higher than that of the old-style 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. and reduce the number of arc extinguishing.

       Magnetron sputtering power supply
       From the perspective of the output waveform, with the development of magnetron sputtering technology itself, it has experienced DC, unipolar pulse, symmetrical bipolar pulse (intermediate frequency magnetron sputtering power supply) and bipolar pulse (asymmetric intermediate frequency magnetron sputtering power supply) radio source) in several ways. At present, the new magnetron sputtering power supply is basically manufactured by high-frequency inverter switching power supply technology, and the intermediate frequency magnetron sputtering power supply has become the first choice for new magnetron sputtering equipment. In order to accurately control the thickness of the film layer, 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 is dense and smooth. To realize this advantage, it is necessary to strictly limit the number of sparks on the target surface and the energy of each spark in the magnetron sputtering process, and minimize the number of macroscopic target particles caused by the sparking moment, which will reduce the compactness and The smoothness will cause the film to fall off in severe cases.

       Bias supply
       Bias power is used in both multi-arc ion and magnetron sputtering coating techniques. Only 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. At present, many devices are equipped with both magnetron sputtering targets and multi-arc targets. When selecting the power of the bias power supply, it should be determined according to the requirements of multiple working hours. The early bias voltage was mainly a DC bias power supply using thyristor technology, and now it is mostly unipolar, DC superimposed pulse and bipolar pulse bias power manufactured by high frequency inverter technology. The bias power supply is mainly used for glow cleaning, ion bombardment and film deposition in the process of multi-arc ion and magnetron sputtering to apply bias voltage on the workpiece to be plated. During glow cleaning, it produces glow; In ion bombardment, it is used to accelerate ions, increase the energy of ion bombardment on the surface of the workpiece, achieve the effect of sputtering cleaning and improve the bonding force of the film layer. It is also used to increase ion energy during film deposition to promote and improve film growth. , will also improve the binding force of the film base. The following are some common waveform bias power supplies:

       Unipolar Pulse Bias Supply
       main feature
       1. High-frequency unipolar pulse bias is applied to the workpiece. Compared with DC bias, due to the existence of voltage interruption gaps, it can effectively reduce the number of sparks 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 the sparking caused by the surface charge accumulation.
       3. The rapid shutdown capability of high-frequency inverter technology can effectively reduce the energy released by each ignition, even when ignition occurs, it can also significantly reduce the degree of damage to the workpiece surface.
       4. The ion energy deposited on the workpiece surface during the pulse gap is very low.
       5. The speed and quality of film formation 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 modes, the problem of low ion energy between unipolar pulse gaps is eliminated.

       Bipolar Pulse Bias Supply
       main feature
       1. The function of the negative pulse is the same as that of the unipolar pulse bias power supply, and 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, the acceleration is easy, so the amplitude of the positive pulse is much smaller than that of the negative pulse, usually 10-100V, and the current integral of the positive and negative pulses should be equal. So the power of the positive power supply is much smaller than the power of the negative power supply.
       2. Bipolar pulse bias becomes unipolar pulse bias when the positive supply voltage is zero.

         The above are just a few common power supplies for vacuum coating equipment. The selection of power supply needs to be selected according to its process requirements and cost performance. When purchasing different vacuum coating equipment, manufacturers will choose different suitable power supplies.