Patent ID: 7737702

Claim:
A plasma reactor comprising: a chamber and workpiece support pedestal in the chamber, the workpiece support pedestal comprising at least one of: (a) at least one chucking electrode and (b) a conductive wafer contact rod; a first impedance matching circuit and an RF bias generator having a first shutoff control input and coupled through said first impedance matching circuit to said workpiece support pedestal; a first RF voltage sensor comprising a differential amplifier having a first amplifier input coupled to one of (a) said contact rod or (b) said at least one chucking electrode, said differential amplifier having a second amplifier input coupled to a D.C. voltage reference; a first arc detection comparator circuit having a first comparison threshold and having a first comparator output and having a first comparator input coupled to an output of said differential amplifier; a process controller ccupled to the first comparator output of said first arc detection comparator circuit and having a process controller output coupled to said first shutoff control input of said RF bias generator; a plasma RF power applicator capable of coupling RF power into said chamber; an RF source power generator having a second shut-off control input; a second impedance matching circuit coupled to said plasma RF power applicator; a second RF power conductor connected between said RF source power generator and said second impedance matching circuit; a second RF voltage sensor coupled to said second RF power conductor; and a second arc detection comparator circuit having a second comparison threshold and having an input coupled to said second RF voltage sensor.