Patent ID: 7297637
Filing Date: 2007-11-20
Classification: H01J,H01L

Abstract:
1. A method of operating a plasma reactor having a pedestal for supporting a semiconductor substrate and an AC power bias source in electrical communication with said pedestal and having an electrical path from ground to said pedestal including a switch, said switch having an open position and a closed position, said method comprising: delivering an electrical signal to said pedestal from said AC power bias source, a voltage of said electrical signal oscillating between a high voltage phase and a low voltage phase; monitoring said voltage of said high voltage phase of said electrical signal for a first selected voltage and a second selected voltage; closing said switch to ground said pedestal during said high voltage phase of said electrical signal when said first selected voltage is reached, said first selected voltage comprising a substantially lower voltage than a second selected voltage; and opening said switch during said high voltage phase of said electrical signal after closing said switch when said second selected voltage is reached, said second selected voltage comprising a substantially higher voltage than said first selected voltage.