The uniformity of the thickness of the film deposited by the magnetron sputtering pvd coating machine is a very important indicator of the film forming properties. Therefore, it is very necessary to study the uniformity of the film layer deposited by the magnetron sputtering pvd coating machine. The following is the vacuum small Let me give you a detailed introduction:

Simply put, magnetron sputtering is in an orthogonal electromagnetic field. The closed magnetic field binds the electrons to make a spiral motion around the target surface. During the motion, they continuously hit the working gas argon and ionize a large number of argon ions. The argon ions act on the electric field. The target is accelerated and bombarded at high speed, and neutral target atoms (or molecules) are sputtered and deposited on the substrate to form a film. Therefore, to achieve uniform coating, the target atoms (or molecules) need to be sputtered uniformly, which requires that the argon ions bombarding the target material are uniform and bombarded uniformly. Since argon ions accelerate and bombard the target under the action of an electric field, uniform bombardment depends largely on the uniformity of the electric field. Argon ions originate from the working gas argon that is constantly impacted by electrons bound by a closed magnetic field in motion, which requires a uniform magnetic field and a uniform working gas argon. However, in the actual magnetron sputtering device, these factors are all non-uniform, which makes it necessary to study the impact of their non-uniformity on the uniformity of film formation.
1. The influence of uneven magnetic field
Since the electric field and magnetic field in an actual magnetron sputtering device are not uniform everywhere, nor are they orthogonal everywhere, they are all functions of space. The written expression of the three-dimensional equation of motion is unsolvable, at least without the solution of elementary functions. Therefore, the impact of magnetic field inhomogeneity on ions, that is, the impact on film formation inhomogeneity, is difficult to calculate. The best way is to conduct detailed analysis with experiments. Figure 1 is the corresponding relationship between the uniformity of the target magnetic field and the uniformity of the film thickness obtained experimentally using a medium-frequency twin target flexible winding magnetron sputtering coating device.
2. Influence of gas inhomogeneity
Generally speaking, uneven gas can be caused by two situations, one is uneven air supply, and the other is uneven air extraction. The normal pumping situation refers to the symmetrical pumping of the twin targets in the vacuum chamber at both ends, which can be considered as uniform pumping; while the front molecular pump switch and the rear molecular pump switch are pumped at one end, which is uneven pumping. Since the air is supplied uniformly but not pumped uniformly, the gas in the vacuum chamber is uneven. It is obvious that when the front molecular pump is turned off and only the rear molecular pump is turned on, the air pressure gradually decreases from front to back, and when the rear molecular pump is turned off and only the front molecular pump is turned on, the air pressure gradually decreases from back to front. The film thickness obtained experimentally is consistent with the change in air pressure after taking into account the influence of the magnetic field.
3. Influence of target base distance and air pressure
The target-base distance of the magnetron sputtering pvd coating machine is also an important process parameter that affects the uniformity of magnetron sputtering film thickness. The film thickness uniformity tends to improve within a certain range as the target-base distance increases. The sputtering working air pressure It is also an important factor affecting the uniformity of film thickness. However, this uniformity is within a small range, because the uniformity produced by increasing the target-base distance is produced by increasing the area on the substrate corresponding to a point on the target, while increasing the working air pressure is produced by increasing particle scattering. Obviously, these factors only work over a small area.