Electrical control of plasma spatial uniformity investigated by planar laser-induced fluorescence

Planar laser-induced fluorescence was performed in the parallel-plate gaseo us electronics conference reference cell to determine two-dimensional maps of the CF2 radical in 89% CF4/11% O-2 chamber-cleaning plasmas. The spatial characteristics of the CF2 density and of broadband optical emission were controlled by varying the current at the upper electrode by adjusting the i mpedance between the upper electrode and ground. The results suggest that e lectrical control of the current paths through the plasma could be used to control the spatial distribution of reactive chemical species, aiding in th e optimization of chamber-cleaning plasmas.