Name: Suzhou cycas Microelectronics Co., Ltd.
Address: 1st floor,B06 building,No.2,Fuxing Road,Zhangjiagang Economic Development Zone,Jiangsu Province 215600PRC
There are many kinds of magnetron sputtering in vacuum furnace. There are different working principles and application objects. However, there is one thing in common: the interaction between magnetic field and electron makes the electron spiral around the target surface, thus increasing the probability of electron impacting argon to produce ions. The generated ions hit the target surface under the action of electric field, thus splashing out of the target. In recent decades of development, we gradually use permanent magnets, rarely coil magnets.
The target source is divided into equilibrium and non-equilibrium type, the equilibrium type target source coating is uniform, and the non-equilibrium type target source coating has strong binding force with the substrate. The balanced target source is mainly used for semiconductor optical films, and the unbalanced target source is mainly used for wear decorative films.
Whether the balance is unbalanced or not, if the magnet is stationary, its magnetic field characteristics determine that the utilization rate of the general target is less than 30%. In order to increase the utilization ratio of the target, the rotating magnetic field can be used. But the rotating magnetic field needs a rotating mechanism, and the sputtering rate should be reduced. Rotating magnetic field is mostly used for large or valuable targets. Such as semiconductor film sputtering. For small equipment and general industrial equipment, magnetic static target source is used.
It is easy to sputter metal and alloy with magnetron target source in vacuum furnace, and easy to ignite and sputter. This is because the target (cathode), plasma, and splashed parts / vacuum cavity can form a circuit. But if sputtering insulator such as ceramic, the circuit will be broken. So people use high-frequency power supply, and a strong capacitance is added to the circuit. In this way, the target 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 complex, so it is difficult to use it on a large scale. In order to solve this problem, magnetron reactive sputtering was invented. It is to use metal target, add argon and reaction gas such as nitrogen or oxygen. When the metal target collides with the part, it combines with the reaction gas to form nitride or oxide due to energy conversion.
Reactive sputtering insulator of magnetron sputtering table seems easy, but it is difficult to operate in practice. The main problem is that the reaction occurs not only on the surface of parts, but also on the surface of anode, vacuum cavity and target source. So as to cause fire-fighting, arc on target source and workpiece surface, etc. The twin target source technology invented by German LeiBao solves this problem well. The principle is that a pair of target sources are cathode and anode to each other, so as to eliminate anodizing or nitriding on the anode surface.
Cooling is necessary for all sources (magnetically controlled, multi arc, ion), because a large part of energy is converted into heat. If there is no cooling or insufficient cooling, this heat will make the target temperature reach more than 1000 degrees and dissolve the whole target.
A magnetic control 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's like a dragon without a finishing touch.
The advantages of medium frequency sputtering are smooth and compact, high film hardness, linear growth of film thickness, no poisoning, moderate temperature rise, but high requirements of equipment and narrow working pressure range, Various control requirements are fast and accurate.
Vacuum furnace multi arc sputtering applies small voltage and large current to the target to make the material ionize (with positive particles), so as to hit the substrate (negative electricity) at high speed and deposit, forming a dense film hard. Mainly used for wear-resistant and corrosion-resistant film. Its disadvantage is that the film is uneven, cavitating and ablating.
The principle of medium frequency sputtering is the same as that of general DC sputtering. The difference is that the cylinder is used as the anode for DC sputtering, and the medium frequency sputtering is in pairs. Whether the cylinder participates in the sputtering depends on the overall design, which is related to the arrangement of anode and cathode in the whole system sputtering process. There are many ways to participate in the ratio period. Different methods can get different sputtering yields, The main technology of if sputtering with different ion density is the design and application of power supply.
At present, sine wave and pulse square wave are two mature ways to output, each of which has its advantages and disadvantages. First, we should consider the type of film, analyze which power output mode is suitable for which film, and use the characteristics of power supply to get the desired film effect.