DIRECT-CURRENT BIAS AS AN ION CURRENT MONITOR IN THE TRANSFORMER COUPLED PLASMA ETCHER

Independent of plasma generation, ion energy can be controlled by applying rf power to a substrate in the transformer coupled plasma etcher. Due to high plasma density of the plasma source, most of rf power to the substrate is confined within the sheath region and used in accelerating ions. This enables development of a simple equation correlating dc bias and ion current density. Based on this equation, ion current densities for different plasma conditions have been measured. The results show good agreement with Langmuir probe measurements.