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Magnetron sputtering is the mainstream method of sputtering which utilizes magnets.
A magnet is placed on the back of the target (material for thin film deposition) in order to enclose electrons in a magnetic field, forming an electron-dense space near the target surface.
A plasma-dense region can be formed in an electron-dense space, as the probability of collision between electrons and Ar is hightened. This allows for more Ar + to hit the target than in the case of non-magnetron sputtering, accelerating the adhesion to the substrate.