Plasma etching apparatus and plasma etching method

A plasma etching method using a plasma etching apparatus, the plasma etching apparatus comprising:

• a processing chamber in which a specimen is subjected to plasma etching processing;
• a specimen holder for holding the specimen;
• a gas supply source for supplying processing gases to the processing chamber;
• a first gas inlet for introducing the processing gases to a center portion of the specimen;
• a second gas inlet for introducing the processing gas to an outer portion of the specimen;
• a first temperature controller provided in the specimen holder for controlling temperature at the center portion of the specimen;
• a second temperature controller provided in the specimen holder for controlling temperature at the outer portion of the specimen;
• a regulator for independently controlling the compositions or the flow rates of the processing gases introduced from the first gas inlet and from the second gas inlet and the temperature controlled with the first temperature controller and the second temperature controller;
• and
• an electromagnetic wave supply unit for sending an electromagnetic wave into the processing chamber,
• wherein the plasma etching method comprises:
• a first etching step of adjusting the temperatures of the center portion and the outer portion of the specimen to desired temperatures, and the flow rates and compositions of the first and second processing gases to desired values respectively;
• an intermediate etching step of heating the specimen by a heater to a desired temperature used in a subsequent, second etching step, and controlling the flow rates and compositions of the first and second processing gases independently;
• and
• the second etching step following the intermediate etching step and continuing plasma etching under desired etching conditions, wherein:
• the intermediate etching step is a transferring period from the temperature of the center portion and the outer portion of the specimen in the first etching step to a temperature of the center portion and the outer portion of the specimen in the second etching step;
• a kind of etching gas used in the intermediate etching step is the same as that used in the second etching step;
• and
• a flow rate of etching gas supplied to the center portion and the outer portion of the specimen in the intermediate etching step is changed gradually from a predetermined gas flow rate to the gas flow rate to be used in the second etching step according to the temperature change of the center portion and the outer portion of the specimen, respectively.