Search

For a rectangular planar direct current (DC) magnetron, anomalous target erosion may occur in the curve-out region and inner side of the curved region. One key factor is that the magnetic field in the end region is weaker than that in the straight region, and another important factor may be that there is a circumferential component of the magnetic field in the curved region. Through a calculation of three-dimensional magnetic field for the rectangular magnetron, a magnet structure shimmed by permanent magnet bars and ferromagnetic bars is proposed to solve the above problems. Through a three-dimensional non-self-consistent particle simulation and the Yamamura/Tawara formula, the target erosion profile could be predicted. The simulation results show that for an improved uniformity in magnetic field, the entire target utilization could be much enhanced.

Plasma properties in a planar DC magnetron system are simulated by a non-self-consistent particle method in two dimensions. Through tracing the trajectories of the energetic electrons in the specified electric field and the magnetic field, and treating the collision process by Monte Carlo method, the spatial profile of ionization events can be obtained conveniently. Assuming that the ions speed up from the ionization points and bombard the target with the energy at these points, and according to the Yamamura/Tawara method, the target erosion can be predicted. The magnetic field is calculated by the finite element method, and the electric field is estimated according to the self-consistent simulation and measured results. The influence of the time step size on the target erosion profile is analysed first to find a proper step size. Then the influence of electric field estimated on the erosion profile is discussed. The erosion profile may become narrower if the sheath thickness is increased. Finally, considering the dynamic erosion process, the erosion profile may get wider over time for the magnetron with shunt bar.