Abstract
The real-time control of both ion density and ion energy in chlorine ICP to etch a polysilicon film was experimentally studied. The TRG-OES was used to measure positive ion density. An I-V probe mounted immediately below the E chuck was adopted to sense rms rf voltage which is proportional to the sheath voltage. Experimental results showed that the closed-loop control had a better repeatability of plasma parameters than the open-loop control.