Measurement and modeling of the unintended capacitive coupling in a cylindrical inductively coupled plasm

Inductively coupled plasmas (ICPs) are widely used in semiconductor processing due to their relatively high electron density at low pressures and their ability to independently control ion bombardment energy. This led to extensive research on the physics and mechanisms of the ICP. In the ICP, there are two main coupling mechanisms. One is inductive coupling, which is coupled to the induced azimuthal electric field from the time varying magnetic field. The other is capacitive coupling, in which energy is transferred by an axial electric field to the plasma. This axial electric field is generated from the voltage difference of the antenna. We show that unintended axial electric field generated by the biased antenna with respect to the grounded chamber, which is largely neglected in most ICP modellings, cannot be ignored. In this study, this additional unintended electric field is measured and modelled for a cylindrical ICP.