Patent ID: 7662232

Claim:
A plasma processing method for plasma-processing an object to be processed, using a plasma processing apparatus comprising: a processing chamber; an antenna for generating electromagnetic radiation in the processing chamber; a shower plate for supplying gases into the processing chamber; a gas dispersion plate for dispersing gas to be supplied to the shower plate; an evacuation means for reducing pressure in the processing chamber; an electrode in the processing chamber, on which an object to be processed is placed; a magnetic coil for generating a magnetic field in the processing chamber; and an electromagnetic radiation power supply for supplying high-frequency power to the antenna, the plasma processing method comprising: a step of dividing the gas dispersion plate into an inner area and an outer area so as to independently control a flow rate or composition of a first processing gas to be supplied from an inner area of the shower plate to the processing chamber, and a flow rate or composition of a second processing gas to be supplied from an outer area of the shower plate to the processing chamber, respectively; a step of (i) mixing plural gases, other than O 2 gas or N 2 gas, supplied from plural gas sources, with each other to make a first gas at a gas junction downstream of gas flow controllers, said gas flow controllers controlling supply of the plural gases from the plural gas sources, and disposed for each of the plural gases, (ii) dividing the first gas into two flows at predetermined flow ratios by a gas distributor disposed downstream of the gas junction, and (iii) adding a second gas, comprising O 2 gas or N 2 gas, to each of the two flows of the divided first gas at a predetermined flow ratio via a gas flow controller; a step of supplying a first processing gas, which is one of the divided gas flows of the first gas having a second gas added thereto, to the inner area of the gas dispersion plate, and supplying a second processing gas, which is the other divided gas flow of the first gas having a second gas added thereto, to the outer area of the gas dispersion plate, respectively; a step of controlling power supply to the magnetic coil to control plasma distribution so as to control a uniformity of process depth; and a step of controlling a ratio of a flow rate of the second gas in the first processing gas and a flow rate of the second gas in the second processing gas to control a composition ratio of the first processing gas and the second processing gas so as to control a uniformity of critical dimension, whereby uniformity of critical dimension across a plane of the object to be processed is controlled independently from control of uniformity of process depth across a plane of the object to be processed.