Patent ID: 7794615
Filing Date: 2010-09-14
Classification: H01J

Abstract:
1. A plasma processing method for performing a plasma process on a substrate disposed in a plasma processing chamber by applying a radio frequency power of a frequency from a radio frequency power supply to a radio frequency electrode disposed inside or outside the chamber via a variable matching unit to generate a plasma in the chamber, the method comprising the steps of: setting an impedance position before operating the plasma processing chamber, by: setting an inner pressure of the chamber to a vacuum level; applying to the radio frequency electrode the radio frequency power at a level that causes no electric discharge; changing an impedance of the variable matching unit to a plurality of impedance positions determined within a variable range; measuring a peak value of a radio frequency voltage in a waveguide line from an output terminal of the variable matching unit to the radio frequency electrode under each of the respective impedance positions and recording the measured peak value; and registering an impedance position having a maximum measured peak value among the plurality of impedance positions, and thereafter, plasma processing by: setting the impedance of the variable matching unit to the registered impedance position; loading the substrate into the chamber; evacuating the inside of the chamber; supplying a processing gas into the chamber; initiating application of the radio frequency power to the radio frequency electrode under the registered impedance position to ignite the plasma in the chamber; and variably controlling the impedance of the variable matching unit such that a load impedance is matched to an output impedance of the radio frequency power supply after the plasma is ignited in the chamber.