| 摘要 |
The invention aims at solving the problems of throughput deterioration, reproducibility deterioration and plasma discharge instability when performing continuous discharge during multiple steps of plasma etching. According to the present invention, the gas supply unit is operated while determining the timing for switching conditions of a plurality of plasma etching steps, and the gas flow rate and gas pressure are controlled so that the pressure of processing gas supplied from the gas supply unit to the processing chamber does not fall below a predetermined pressure immediately subsequent to switching steps. For example, upon switching processing gases, the end point of a step is predicted based on an interference film thickness meter, and prior to the end point by two seconds or more, the flow rate of MFC is set to the gas flow rate for the subsequent step and the gas is flown to the exhaust device, so that simultaneously as when the end point signal is received, the processing gases are switched by switching valves.
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