Effect of magnetic field configuration in the cathodic polymerization systems with two anode magnetrons

Abstract

Direct current glow discharge can be utilized in plasma polymer coating of metal substrates by using the substrate as the cathode (cathodic polymerization). By using an anode equipped with magnetic enhancement, the anode magnetron cathodic polymerization can be effectively operated in low pressure regime, in which a tight barrier type plasma polymer can be formed. When two magnetrons are used against a cathode (substrate), the configurations of magnetic field employed in each magnetron become an important factor of the system. In one case [parallel magnetron (PM)], in which the identical magnetrons are used; magnetic field near the substrate (cathode) emanating from two magnetrons are parallel. In another case [opposite magnetron (OM)], in which magnet arrangement is reversed in one magnetron, magnetic fields near the substrate are opposite. Plasma polymerization with no magnetron shows the edge effect (higher deposition rate near the edge of cathode). With anode magnetrons (OM or PM), the edge effect is eliminated and higher deposition rates, compared to that obtained without magnetron, were obtained in the majority of electrode area. The uniformity of the deposition rate distribution is better with the OM configuration than with the PM configuration. The distance between electrodes influences the distribution of the deposition rate with the PM configuration (less uniform with small distance), but has little effect with the OM configuration. The advantage of having anode magnetrons diminishes at system pressure higher than 50 mTorr.