Electrode treatment for plasma patterning of polymers

This patent specification describes a technique for protectively coating the electrodes in a plasma patterning device so as to minimize the effect of backscattering of electrode material. The potentials present in a patterning chamber are such that electrode sputtering material may occur. If the material of the electrode where the sample is mounted (RIE mode) or the material of the counterelectrode (plasma etch mode) of the reaction chamber is not etchable in the etchant present, electrode material can be sputtered off, backscattered on the polymer surface, and cause incomplete etching. Polymer films, patterned in fine dimensions by masking and etching, are widely used in microelectronics. If backscattered material present in the etch area cannot be etched as fast as the polymer film, the back-scattered material on the polymer film surface will cause partial masking and incomplete etching, leaving spikes of polymer. Coating the electrode with the same polymer, or with a photoresist or different polymer of corresponding etch rate, precludes such incomplete etching; the etched hole is very clean, without spikes. The coating on the electrodes may be very thick so as not to require frequent recoating