Electrode separation and convex electrode surfaces in plasma etching

The etch rate is strongly dependent on the electrode spacing. This dependence can be applied to equalize the etch progress across a substrate wafer by employing a spherical electrode surface opposite the substrate. An example of how this surface is to be selected has been given. However, it should be pointed out that this example is tied to the particular parameters of power, pressure, and gas composition chosen for this experiment and that for all other settings a new plot like Fig.5 has to be obtained first in order to select the radius of the spherical electrode surface and the proper distance of the electrodes. (IAF)