Many people do not know that the coating technology of magnetron sputtering pvd coating machine is also divided into types. The products plated are different, and the magnetron sputtering technology used is also different. Today, the editor of Huicheng Vacuum will explain the intermediate frequency magnetron sputtering for the general. The coating technology of the pvd coating machine, I hope to help everyone.

The medium frequency magnetron sputtering pvd coating machine coating technology is divided into balanced and unbalanced target sources. The balanced target source has a uniform coating, and the unbalanced target source has a strong bonding force between the coating layer and the substrate. Balanced target sources are mostly used for semiconductor optical films, and unbalanced targets are mostly used for wear decorative films. Regardless of balance or unbalance, if the magnet is stationary, its magnetic field characteristics determine that the general target utilization rate is less than 30%. In order to increase the utilization rate of the target material, a rotating magnetic field can be used. But rotating the magnetic field requires a rotating mechanism, and at the same time the sputtering rate is reduced. Rotating magnetic fields are mostly used for large or expensive targets. Such as semiconductor film sputtering. For small equipment and general industrial equipment, the magnetic field static target source is often used.
It is easy to sputter metals and alloys with magnetron target sources, and ignition and sputtering are convenient. This is because the target (cathode), plasma, and the vacuum chamber of the sputtered part can form a circuit. But if sputtering insulators such as ceramics, the circuit is broken. So people use high-frequency power supply, and add a strong capacitor to the loop. In this way, the target material becomes a capacitor in the insulating circuit. However, the high-frequency magnetron sputtering power supply is expensive, the sputtering rate is very small, and the grounding technology is very complicated, so it is difficult to use it on a large scale. To solve this problem, magnetron reactive sputtering was invented. That is, using a metal target, adding argon and a reactive gas such as nitrogen or oxygen. When the metal target hits the part, it combines with the reactive gas to form nitrides or oxides due to energy conversion.
The magnetron reactive sputtering of insulators seems easy, but the actual operation is difficult. The main problem is that the reaction occurs not only on the surface of the part, but also on the anode, the surface of the vacuum chamber, and the surface of the target source. Thereby causing fire extinguishing, target source and workpiece surface arcing and so on. The twin target source technology invented by Leybold in Germany solves this problem very well. The principle is that a pair of target sources are the cathode and anode of each other, thereby eliminating the oxidation or nitridation of the anode surface. Cooling is necessary for all sources (magnetron, multi-arc, ions), because a large part of the energy is converted into heat. If there is no cooling or insufficient cooling, this heat will make the target source temperature reach more than 1,000 degrees and melt the entire target source. . A magnetron equipment is often very expensive, but it is easy to spend money on other equipment such as vacuum pump, MFC, film thickness measurement and ignore the target source. No matter how good the magnetron sputtering equipment is without a good target source, it is like drawing a dragon without the finishing touch.
       Multi-arc sputtering applies a small voltage and a large current to the target to ionize the material (positively charged particles), thereby hitting the substrate (negatively charged) at a high speed and deposit, forming a dense film hard film. Mainly used for wear and corrosion resistant films. The disadvantage is that the positive and negative electric shocks cause uneven film, holes and ablation. The principle of intermediate frequency sputtering is the same as that of general DC sputtering. The difference is that DC sputtering uses the cylinder as an anode, while intermediate frequency sputtering is paired. Whether the cylinder participates in must depend on the overall design, and the whole system In the sputtering process, the arrangement of anode and cathode is related, and there are many ways to participate in the ratio cycle. Different methods can obtain different sputtering yields and different ion densities. The main technology of intermediate frequency sputtering lies in the design and application of the power supply. At present, the two methods of outputting sine wave and pulse square wave are more mature. Each has its own advantages and disadvantages. First, we should consider the type of film, and analyze which power output method is suitable for which film. You can use the characteristics of the power supply to get the desired output. Coating effect. Intermediate frequency sputtering is also a kind of magnetron sputtering. Generally, the design of magnetron sputtering target of pvd coating machine and the design of magnetic field are the focus of various technologies. Several well-known sputtering target manufacturers in the world have The design of the target magnetic field is quite professional. Changing the magnetic field design can get different plasma evaporation. The path of electrons and the distribution of plasma, so the sputtering target magnetic field is the technical secret of each company. About cathode arc (that is, ion plating) , magnetron sputtering, and crucible evaporation all belong to PVD (physical vapor deposition). The crucible evaporation is mainly a phase change, and the evaporation target has only a few electron volts of energy.
Therefore, the film adhesion is small, but the deposition rate is high, and it is mostly used for optical coating. In magnetron sputtering, argon ions impact the target material to deposit atomic and molecular fragments of the target material on the parts, and the kinetic energy of the target material can reach hundreds or even thousands of electron volts. It is a truly neutral nano-scale coating. After the cathode arc starts, the high temperature of the target surface melts the material metallurgically, and the strong electric field then almost completely ionizes the melted material, forming a film under the combined action of the target power supply and the bias voltage of the part. It seems that cathodic arc plating is more advanced, but it is not. First of all, the melting process of the target surface is very random and uncontrollable, and the ions are plated on the parts in clusters. The uniformity and smoothness of the plated parts are difficult to guarantee. Generally speaking, cathode arc plating is a welding process under vacuum, and the cathode arc power supply and welding power supply are very similar in principle. Cathode arc technology mainly originates from the former Soviet Union. It is popular in my country for various reasons. Simple power supply is a big factor. But technology keeps improving. In recent years, the technology of filtering cathodic arc has developed rapidly, which avoids the disadvantage of uneven film formation.
Intermediate frequency magnetron sputtering has high requirements on the design of target and magnetic field as well as working air pressure, and the deposition rate of intermediate frequency magnetron sputtering is 2 to 3 times that of DC magnetron sputtering. Intermediate frequency magnetron sputtering works with two targets to prepare compound films. Due to its low ionization rate, it is difficult to find an optimal poisoning point, and the flow control of working gas is very strict. If the control is not good, it is difficult to prepare a uniform and good bonding film layer. Then, the design of the magnetic field is mainly about the uniformity of the magnetic field distribution, which can not only improve the utilization rate of the target material, but also greatly improve the stability of the optimal poisoning point when working. The properties are far lower than the multi-arc target surface, and the distance from the workpiece is very important. If the ions are too close to the workpiece, the bombardment of the workpiece can damage the film layer. The intermediate frequency target uses three pairs of targets, and some use three pairs. The targets are relatively large. As far as the intermediate frequency is concerned, most of them are metal-plated workpieces. Such vacuum furnaces are generally made relatively large. , You can put down a lot of task pieces, and the plated film is more dense.