Patent ID: 8262847

Claim:
A capacitively-coupled plasma processing system having a plasma processing chamber for processing a substrate, the capacitively-coupled plasma processing system comprising: at least an upper electrode and a lower electrode for processing said substrate, said substrate being disposed on said lower electrode during plasma processing, said lower electrode is provided at least a first RF signal, said first RF signal having a first RF frequency, said first RF signal configured for exciting gas to generate plasma in said plasma processing chamber; a multiple-RF-frequency signal generator coupled with said lower electrode for providing said first RF signal; and a phase-mirroring arrangement coupled to at least said upper electrode and said lower electrode, said phase-mirroring arrangement including at least a detector for detecting a phase of said first RF signal and an amplitude of said first RF signal, said phase-mirroring arrangement further including at least a control circuit for generating a control signal based on said phase of said first RF signal and said amplitude of said first RF signal without using any data resulted from monitoring said upper electrode, said phase-mirroring arrangement further including at least an RF signal generator for generating a generated RF signal in response to said control signal, said RF signal generator being coupled to said detector through said control circuit, said control circuit controlling at least an amplitude of said generated RF signal, said phase-mirroring arrangement further including at least an amplifier configured to amplify said generated RF signal to produce a second RF signal and configured to provide said second RF signal to said upper electrode, said second RF signal having a second frequency, a value of said second frequency being equal to a value of said first RF frequency, a phase of said second RF signal being offset from a phase of said first RF signal by a value that is less than 10%, said substrate being processed while said second RF signal is provided to said upper electrode.