It is found that a properly tuned segmented coil system allows external control of the radial plasma density profile in an inside-type, large-area inductively coupled plasma. This coil system is composed of inner and outer coil segments and an external variable inductor. he external variable inductor is used to balance coil currents between the two coil segments for plasma uniformity control. The measured results indicate that radial plasma spread can be controlled and optimized with this external variable inductor.