An apparatus may include a substrate support portion, a plasma generation chamber, electrodes, and a power source. The substrate support portion supports a substrate including an insulating layer and a substrate bulk. The plasma generation chamber may include chamber wall portions, a gas port, and a plasma application aperture and is configured to contain a gas. The plasma application aperture may be covered by a portion of the substrate. Each electrode may protrude into or extend into an interior portion of the plasma generation chamber. The power source may be coupled to a particular electrode, and the power source may be configured to apply a voltage to the particular electrode. Application of the voltage to the particular electrode generates a plasma within the plasma generation chamber, whereby generation of the plasma results in a conductive path through the insulating layer of the substrate between the plasma and the substrate bulk.