The operation of the magnetron sputtering vacuum coating machine is to make the electrons bombard the argon ions formed by the argon gas and then bombard the target by the orthogonal magnetic field under the vacuum state, and the target ions are deposited on the surface of the workpiece to form coating. So we can consider that the vacuum state, magnetic field and argon are three aspects that related to the uniformity of the film thickness.
The vacuum state is controlled by air pumping system. Each pumping port must be actuated at the same time under consistent strength so that the uniformity of pumping can be ensured. If the pumping is not uniform, the pressure in the vacuum chamber cannot be uniform, as the pressure has some influence on the movement of ions. In addition, the pumping time must be controlled. Too short will cause insufficient vacuum, but it will be a waste of resources if it is too long. But the existence of vacuum gauges makes it necessary.
The magnetic field works orthogonally, but it is impossible to make the magnetic field intensity is 100% uniform. In general, where the magnetic field is strong, the film thickness will be large, and vice versa, so the film thickness will be inconsistent.
The uniformity of the argon gas supply also affects the uniformity of the film layer. The principle is similar to the vacuum degree. Due to the entry of argon gas, the pressure in the vacuum chamber will change accordingly. Uniformity of the film thickness can be controlled by the uniform pressure.
Although there are always several factors that cause unevenness of the film, but the pass rate of the film is very high if the correct operation of the vacuum coating machine is done.