Patent ID: 6857387

Claim:
Apparatus for fabricating a workpiece, comprising: a plasma chamber; first and second electrodes mounted within the plasma chamber; a chuck for positioning a workpiece between the first and second electrodes; a low frequency power supply connected to supply to the first electrode an electrical signal having a first frequency; a high frequency power supply connected to supply to the second electrode an electrical signal having a second frequency that is substantially higher than the first frequency; one or more capacitors connected to the first electrode at a plurality of spatially distributed locations on the first electrode, wherein each capacitor is connected between the first electrode and electrical ground; wherein the high and low frequency power supplies in combination excite a plasma in a region between the first and second electrodes; and wherein the spatial distribution of said locations and the respective capacitances of said one or more capacitors are established so as to substantially increase the spatial uniformity of the density of said plasma in said region relative to the spatial uniformity of the density of said plasma in the absence of the one or more capacitors.