Patent ID: 7067761

Claim:
A semiconductor device manufacturing system comprising: a vacuum chamber provided with a cathode electrode for holding a substrate to be processed and into which a reactive gas for generating discharging plasma by the application of a high-frequency electric power is introduced; a high-frequency power supply connected to said cathode electrode, for applying a high-frequency electric power to said cathode electrode; a cooling gas carrying path provided at said cathode electrode and into which a cooling gas is introduced to cool said substrate; an electronic valve provided at said cooling gas carrying path in such a manner that the pressure of said cooling gas introduced into said cooling gas carrying path is adjusted; a measuring circuit connected to said cathode electrode, for measuring at least one of the impedance of a system including said plasma, the peak-to-peak voltage of a high-frequency signal applied to said plasma, and a self-bias voltage applied to said cathode electrode; and a control circuit for receiving the measured value from said measuring circuit, for supplying an output based on said measured value, and for controlling the operation of said valve in such a manner that the measured value of said measuring circuit is kept at a specific value.