Multiple coil antenna for inductively-coupled plasma generation systems

摘要

A radio frequency plasma multiple-coil antenna allows for controllable, uniform inductive coupling within a plasma reactor. According to exemplary embodiments, multiple coils are positioned on a dielectric window of a plasma chamber, and are powered by a single radio frequency generator and tuned by a single matching network. Each coil is either planar or a combination of a planar coil and a vertically stacked helical coil. The input end of each coil is connected to an input tuning capacitor and the output end is terminated to the ground through an output tuning capacitor. The location of the maximum inductive coupling of the radio frequency to the plasma is mainly determined by the output capacitor, while the input capacitor is mainly used to adjust current magnitude into each coil. By adjusting the current magnitude and the location of the maximum inductive coupling within each coil, the plasma density in different radial and azimuthal regions can be varied and controlled, and therefore, radially and azimuthally uniform plasma can be achieved.