Electrically tuned matching networks using adjustable inductance elements

Abstract

A plasma processing system for use in fabricating electronic devices including an RF generator; a process chamber including an electrical load which produces a plasma within the chamber when powered by the RF generator; an electronically tunable matching network connected between the RF generator and the electrical load of the process chamber, wherein during operation the matching network couples power from the RF generator into the plasma within the process chamber; and a control circuit connected to the matching network, wherein during operation the control circuit electronically adjusts the matching network so as to control a transfer of power from the RF generator into the plasma in the process chamber. The matching network includes an electronically tunable variable inductor including a core made of a material which exhibits a non-linear relationship between magnetic field intensity, H, and magnetic flux density, B. The core is configured as a closed loop defining a central opening. A magnetization coil is wound around the core so that the core forms a closed magnetic flux path for the magnetization coil. The magnetization coil includes two input terminals for coupling an electrical signal from the control circuit into the windings of the magnetization coil. There is also a primary coil formed around the outside of said closed-loop core and having input terminals for receiving a high-frequency current signal from the RF generator.