Correlation between the cathode erosion, the optical emission and the magnetic field distribution in magnetron sputtering systems

In magnetron sputtering systems it is known that, due to the presence of a non-uniform magnetic field distribution, neither the erosion of the cathode nor the optical emission of the discharge are uniform. In this work, the magnetic field distribution near a magnetron cathode is measured experimentally and fitted by means of a convenient mathematical expression. The experimental spectroscopic optical tomography of the discharge is performed during the sputtering process, while the erosion profile of the cathode is measured after sputtering. It appears that there is a correlation between these measurements. In order to explain these results, the equations of motion of the electrons are solved numerically for the case of the fitted magnetic field distribution, plus a non-uniform electric field. The zone for confinement of electrons near the cathode is seen to be in accordance with the experimental data.