Patent ID: 8193097
Filing Date: 2012-06-05
Classification: H01J

Abstract:
1. An impedance adjustment method in a plasma processing apparatus including an evacuable processing chamber accommodating therein a substrate to be processed; a first and a second electrode installed to face each other in the processing chamber, the first electrode being divided into an inner and an outer electrode; and a radio frequency power supply unit for supplying a plasma forming radio frequency power to the first electrode; and a processing gas supply unit for supplying a processing gas into the processing chamber in order to perform a plasma processing on the substrate to be processed by generating a plasma of the processing gas between the first and the second electrode, the method comprising the steps of: connecting a power feed rod to the inner electrode; installing a cylindrical power feeder such that a lower portion thereof is connected to the outer electrode and an upper portion thereof is electrically connected to the radio frequency power supply unit; installing a cylindrical grounding conductor upwardly extended from a sidewall of the processing chamber, wherein the outer electrode, the cylindrical power feeder and the cylindrical grounding conductor constitute an outer coaxial cable path using the outer electrode and the cylindrical power feeder as an outer waveguide and wherein the power feed rod and the cylindrical grounding conductor constitute an inner coaxial cable path using the power feed rod as an inner waveguide; installing a variable capacitor on the power feed rod; installing a detector for detecting an apparatus state to be used to search a point of a circuit where a largest radio frequency power flows in the inner electrode, the circuit allowing a radio frequency current to flow in the inner electrode of the first electrode; searching the point of the circuit by detecting a signal of the apparatus state with the detector while varying a capacitance of the variable capacitor by changing a setting value thereof while the plasma is generated, thereby finding a specific setting value of the variable capacitor at the point, wherein the variable capacitor has a specified capacitance at the specific setting value; and adjusting the specific setting value of the variable capacitor at the point to a reference setting value, such that the variable capacitor has the specified capacitance at the reference setting value.