Electrical Variable Capacitor Using Symmetrical Switch Configuration in RF Plasma System

摘要

This paper introduces a novel method to reduce the voltage stress experienced by Electrical Variable Capacitor (EVC)circuit of 320V/1kW/13.56MHz having an asymmetrical switch configuration applied in impedance matching circuit of RF plasma system. The method employs a symmetrical switch configuration in place of an asymmetrical switch configuration in each of the capacitor leg in the EVC circuit. The proposed idea successfully reduces the voltage stress in the EVC circuit owing to symmetrical charging and discharging mode and can be applied in the impedance matching circuit of high-power and high-frequency RF plasma system. The proposed circuit topology is effectively supported by experiment which have successfully verified that the voltage stress on the switch of the EVC circuit is reduced by more than 40%.