Simulation Of Electronmagnetic Field For Plasma Enhanced Magnetron Sputtering

With the continuous development of the Townsend discharge andglow discharge theory,low temperature plasma techniques have beenapplied to the film deposition,surface modification,microelectronic devicefabrication and semiconductor etching. Magnetron sputtering techniquehas become one of the main methods to prepare films. The magnetic fielddistribution，the plasma density and temperature distributions will directlyaffect the quality of films. Therefore, it is very meaningful to select theappropriate model to simulate magnetron sputtering ionizationmechanism.The numerical simulation of the magnetron distribution wascalculated by the mathematical model based on Maxwell’s equations. Thenumerical solutions of the model were obtained by introducing of theboundary conditions of the cylindrical magnetron sputtering rig. Thephysical model of DC discharge was established by using the finitedifference method, based on the theory of magnetic fluid anddrift-diffusion approximation. The discharge atmosphere was argon. Thespace and time distributions of the discharge plasma, i.e. electron, argonion, metastable and neutral particles, were investigated by the solution ofthe DC glow discharge physical model. Fortran language was used inprogramming.The results showed that magnetic field intensity of the unbalancedmagnetron configuration, which was caused by the increase of outer coilcurrent and resulted in N pole strengthening, was strongest near thesurface of target, stronger and more uniform within certain distance awayfrom the surface of the target than that of balanced magnetronconfiguration. DC glow discharge began with space non-uniform district,i.e. the frontiers of the probe plates. Glow discharge tended to beequilibrium, and plasma gathered above the surface of target, within5cm.Electrons was firstly reached above the surface of target, then ionsbecause the mass of electron is much lighter than the masses of ions. Theconcentrations of electrons and ions decreased as the distance from the surface of target increases, the concentrations at10cm were half of thoseat5cm, and the concentration decreased in3orders when the distancewas longer than15cm. At the beginning of the glow discharge, ions in theplasma were contributed by Ar ionization. Metastable particles wereionized then, and were the main source of the ions in the plasma. Ions bythe penning effect was the smallest part in the whole plasma.