Magnetic clips for use with a substrate holder for holding a substrate in a processing chamber of a plasma treatment system. The clip includes first and second body members each having a clamping surface and a magnet. The first body member is configured to be mechanically connected with the substrate holder. The second body member is pivotally connected by a hinge with the first body member for movement relative to the first body member between closed and opened positions. In the closed position, an edge region of the substrate is positioned between the clamping surfaces. In the opened position, the edge region is released. The magnet on the second body member magnetically attracts the magnet on the first body member, when the second body member is in the closed position, to apply a force that restrains movement of the edge region of the substrate relative to the clamping surfaces.