Electrode designs for controlling uniformity profiles in plasma processing reactors

摘要

Electrode designs for reducing the problem of non-uniform etch in large diameter substrates are presented. The electrode opposite the substrate being etched in a plasma reactor can be tailored as to its shape so as to control the uniformity of the etching across the substrate. This is achieved with a number of generally dome-shaped electrode structures including generally cone-shaped electrodes, generally pyramidally-shaped electrodes and generally hemispherically-shaped electrodes. It is believed that non-uniformity of etching is due, at least in part, to excess ion density at the center of the reactor. The dome-shaped electrodes serve to disperse the high concentration of ions from the center of the reactor out toward the periphery of the substrate and thereby even out the ion density distribution across the substrate being etched. The electrodes are useable in diode plasma reactors, triode plasma reactors and ICP plasma reactors.