Plasma processor with electrode responsive to multiple RF frequencies

• Main Authors: DHINDSA RAJ, KOZAKEVICH FELIX, TRUSSELL DAVID DOUGLAS
• Format: Patent
• Language: English
• Published: 30.01.2007
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; SEMICONDUCTOR DEVICES

A plasma processor processing a workpiece includes sources having frequencies 2 MHz, 27 MHz, and 60 MHz, applied by three matching networks to an electrode in a vacuum chamber including the workpiece. Alternatively 60 MHz is applied to a second electrode by a fourth matching network. The matching networks, substantially tuned to the frequencies of the sources driving them, include series inductances so the 2 MHz inductance exceeds the 27 MHz network inductance, and the 27 MHz network inductance exceeds the inductances of the 60 MHz networks. The matching networks attenuate by at least 26 DB the frequencies of the sources that do not drive them. Shunt inductors between the 27 and 60 MHz sources decouple 2 MHz from the 27 and 60 MHz sources. A series resonant circuit (resonant to about 5 MHz) shunts the 2 MHz network and the electrode to help match the 2 MHz source to the electrode.