The effect of substrate connections on charging potentials and current densities

Wafer potentials and charging currents have been found to depend on the area of antennas connected to substrate. In a medium-density plasma dielectric etch tool, smaller substrate-connected antennas resulted in large charging potentials and current densities on separate test structures, whereas larger antennas produced much lower potentials and current densities. In a high-density plasma metal etch tool, this dependence was significantly smaller. These findings imply that circuit layout can strongly modulate damage in test structures and product.