Numerical study of the characteristics of erosion in magnetron sputtering

The erosion pattern of a magnetron sputter target has been investigated numerically. A two-dimensional plasma simulation (particle in cell-Monte Carlo collision) was used to investigate the variation in incident ion flux distribution at the target surface with magnetic field, gas pressure and cathode voltage. Using the mean incident energy of Ar ions together with the yield data for aluminum, the distribution of incident flux was converted to an erosion profile, which was then fitted to a Gaussian function. The fitting parameters indicate that the erosion shape becomes narrower and more tapered for lower pressure and higher magnetic field intensity. However, the Gaussian fitting degrades rapidly away from the erosion center. A new fitting function was introduced employing the concept of a virtual line source in a collisionless plasma.