Discharge properties of a cylindrical capacitively coupled plasma discharge with an axisymmetric magnetic field

Radio-Frequency Capacitively Coupled Plasma (CCP) discharges in semiconductor device manufacturing are indispensable for surface modifications, including PECVD and plasma etching. In such discharges, enhanced efficiency of the plasma system and control over vital discharge parameters are crucial for critical process conditions. We present a novel CCP device with a 13.56 MHz powered cylindrical electrode, sets of grounded annular rings, and grids on its axial ends. The axial magnetic field (B) generates E × B drifts in the azimuthal direction, supporting enhanced and homogeneous plasma density and providing uniform surface modification. The discharge characteristics and bulk plasma diagnostic, including the Energy Distribution Functions of electrons (EEDF) and ions (IEDF), are performed using an inline IV sensor, RF-compensated Langmuir probe, and Hiden EQP-300, respectively. The experimental results show a range of B-fields where the discharge is highly efficient with lower electron temperature. Outside this range, the plasma density drops, followed by an increase in the electron temperature. The behavior is attributed to the transition from geometrical asymmetry to magnetic field-associated symmetry due to reduced radial losses. The EEDF shows a transition from bi-Maxwellian for B=0 to Maxwellian at intermediate B and a bi-Maxwellian at high B. The B-field's effect on the IEDF, a plausible explanation for the observations, and potential applications of the device are highlighted.