It is well known that the vacuum magnetron sputtering coating machine uses magnetron sputtering target materials, so the magnetron sputtering target materials will be poisoned when coating and sputtering. The current situation of target poisoning is a headache for everyone. It not only wastes the target materials, but also delays the production time, which is a headache.

In general, the secondary electron emission coefficient of metal compounds is higher than that of metals. After the target is poisoned, the surface of the target is all metal compounds. After being bombarded by ions, the number of secondary electrons released increases, which improves the space conductivity, reduces the plasma impedance, and causes the sputtering voltage to decrease. Thus, the sputtering rate is reduced. Generally, the sputtering voltage of magnetron sputtering is 400V-600V. When the target is poisoned, the sputtering voltage will be significantly reduced. (2) The sputtering rate of metal target is different from that of compound target. Generally, the sputtering coefficient of metal is higher than that of compound, so the sputtering rate of target is low after poisoning. (3) The sputtering efficiency of reactive sputtered gas is inherently lower than that of inert gas, so when the proportion of reactive gas increases, the comprehensive sputtering rate decreases.
The main factor affecting target poisoning of magnetron sputtering vacuum coating machine is the ratio of reaction gas and sputtering gas. Excessive reaction gas will lead to target poisoning. In the process of reactive sputtering process, the target surface sputtering channel area is covered by reaction products or the reaction products are stripped to re expose the metal surface. If the rate of compound formation is greater than the rate of compound stripping, the covering area of compound increases. At a certain power, the amount of reaction gas involved in the formation of compounds increases, and the rate of compound formation increases. If the amount of reaction gas increases excessively, the compound coverage area will increase. If the reaction gas flow cannot be adjusted in time, the rate of compound coverage area increase will not be inhibited, and the sputtering channel will be further covered by the compound. When the sputtering target is completely covered by the compound, the target will be completely poisoned.
Common target poisoning phenomena of magnetron sputtering vacuum coating machine include: (1) Positive ion accumulation: when the target is poisoned, a layer of insulating film is formed on the target surface. When positive ions reach the cathode target surface, due to the barrier of the insulating layer, they cannot directly enter the cathode target surface, but are stacked on the target surface, which is easy to generate cold field arc discharge - arcing, making cathode sputtering impossible. (2) Anode disappearance: when the target is poisoned, an insulating film is also deposited on the wall of the grounded vacuum chamber, and electrons reaching the anode cannot enter the anode, forming the phenomenon of anode disappearance.