Patent ID: 8083889

Claim:
A plasma etching apparatus comprising: a processing chamber configured to generate plasma therein and to perform plasma etching on an object to be processed; a gas supply source configured to supply processing gas for the processing chamber; a gas shunt configured to divide the processing gas from the gas supplied from the gas supply source; a first gas inlet provided at a center portion of a top of the processing chamber and configured to introduce a first processing gas divided by the gas shunt to the processing chamber; a second gas inlet provided at a top of the processing chamber and on an outer side relative to the first gas inlet, the second gas inlet being configured to introduce a second processing gas divided by the gas shunt to the processing chamber; an oxygen gas supply means for supplying oxygen gas to at least one of a gas pipe between the gas shunt and the first gas inlet and a gas pipe between the gas shunt and the second gas inlet; a plurality of flow rate regulators configured to regulate flow rates of the first and second processing gases; a first photoreception section disposed at a center portion of a top of the processing chamber, the first photoreception section being configured to receive emission light of the plasma; a second photoreception section disposed at an outer side of the top of the processing chamber, the second photoreception section being configured to receive the plasma emission light; a spectroscopic section configured to decompose the plasma emission light in the processing chamber into a plurality of wavelength components, wherein the plasma emission light is received at the first and the second photoreception sections; a database configured to store plasma emission light data decomposed into a plurality of the wavelength components in the spectroscopic section; an analysis section configured to calculate gate widths of the object to be processed in a center portion and an outer region of the object to be processed from the plasma emission light data of the database using a polynomial obtained in advance which shows a relationship between the plasma emission light data and the gate widths, and to calculate the flow rate of a plurality of the flow rate regulators, the flow rate of the oxygen gas, and a ratio of divided flow of the gas shunt, that are capable of approximating the calculated gate widths respectively to a target completion size; and a control unit configured to control each of the flow rate of a plurality of the flow rate regulators, the flow rate of the oxygen gas, and the ratio of divided flow of the gas shunt, based on an analysis result in the analysis section.