A plasma etching system that includes a plasma processing chamber, a substrate holder disposed in the plasma processing chamber, a RF power source configured to generate a plasma in the plasma processing chamber, a first magnet disposed above the substrate holder, the first magnet configured to apply, in the plasma processing chamber, an azimuthally symmetric magnetic field that is independent from a magnetic field generated by the RF power source, and a second magnet disposed below the substrate holder and configured to modify the azimuthally symmetric magnetic field and create a ring X point between the first magnet and the second magnet, where positions of the first magnet and the second magnet are arranged such that the ring X point is located nearer to an edge of the substrate holder than a center of the substrate holder.