Non-invasive real-time sheath diagnostics using RF wall sensor: application to transformer coupled plasma-reactive ion etch system

Abstract This study investigates plasma sheath dynamics in electronegative oxygen plasmas using a non-invasive plasma sheath monitoring sensor (PSMS). The PSMS detects radio-frequency (RF) magnetic field variations induced by sheath displacement currents, enabling real-time monitoring of sheath dynamics without perturbing the plasma. Variations in the PSMS signal are primarily attributed to changes in sheath capacitance caused by plasma density evolution and ion species transitions. Experiments