Reason for unevenness in magnetron sputtering vacuum coating

What are the factors that cause the unevenness of the magnetron sputtering vacuum coating machine? The professional who is engaged in this work is actually quite familiar. It can be divided into the following factors: vacuum state, magnetic field, argon.

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The operation of the magnetron sputtering vacuum coating machine is to bombard the target by argon ions formed by electrons bombarding argon under the vacuum state, and the target ions are deposited on the surface of the workpiece to form a film.

The vacuum state requires a pumping system for control. Each pumping port must be started at the same time and the force is the same. This can control the uniformity of pumping. If the pumping is not uniform, the pressure in the vacuum chamber cannot be uniform. The pressure has a certain influence on the movement of ions. In addition, the pumping time should be controlled. Too short will cause insufficient vacuum, but it will be too long and waste resources. However, if there is a vacuum gauge, it is not a problem to control it.

The magnetic field is orthogonal, but it is impossible to make the magnetic field strength 100% uniform. Generally, where the magnetic field is strong, the film thickness is large, and on the contrary, it is small, so the film thickness is inconsistent. However, in the production process, the unevenness of the film due to the non-uniform magnetic field is not common. Why?

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It turns out that although the strength of the magnetic field is not well controlled, at the same time, the workpiece is also running at the same time, and the target atom is deposited multiple times. This case ends the coating process. Although some parts are thick and some parts are thin for a while, another is In the time, under the action of the strong magnetic field, it is thicker in the original thin part, and deposited on the thick part, so many times, the uniformity of the whole film layer after the final film formation is quite good.

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The uniformity of gas supply of argon also affects the uniformity of the membrane. The principle is actually similar to the degree of vacuum. Because of the entry of argon, the pressure inside the vacuum chamber changes, and the uniform pressure can be controlled into a magnetron sputtering vacuum. The uniformity of the film thickness of the coating machine.