A cross-corner effect in a rectangular sputtering magnetron

Abstract

Electron trajectories, ionization distribution, and magnetic field in a conventional rectangular sputtering magnetron cathode are simulated in order to understand the mechanism of a cross-corner effect, which is a common phenomenon associated with rectangular magnetron cathodes and which limits the target utilization. It is found that once the magnetic field in end region of the cathode is different from that in straightway, the cross-corner effect exists. Using a fourth-order Runge–Kutta method, the electron trajectories are simulated, showing that the electrons may drift much faster in the end region than in the straightway and pass quickly to cross-corner region. A Monte-Carlo method is employed to simulate ionization distribution and to quantitatively predict target erosion. The results show denser ionization in the cross-corner region, causing more intensive erosion in that area. We demonstrate that by properly modifying the magnet field in the end region, the electron drift velocity and ionization distribution can be controlled and the cross-corner effect may be significantly reduced.