| 摘要 |
PROBLEM TO BE SOLVED: To provide a method which need not set an etching condition accompanying an excessive margin in carrying out contact etching with a high aspect ratio to suppress the occurrence of etching stoppage even if the state of chamber changes in a mass production process under the best etching condition. SOLUTION: An oxygen flow rate control unit 7 calculates a rate of change per unit time of a difference between the emission intensity of CFx radicals and that of SiFx radicals output from emission intensity monitors 5 and 6 during a preset time. When the rate of change exceeds a prescribed threshold any number of times in succession, the control unit 7 determines that "etch stoppage is expected to happen", and increases an oxygen flow rate based on the determination. After increasing the oxygen flow rate, the control unit 7 continues to calculate the rate of change until the preset time is over. When the rate of change does not exceed the threshold at all during a given time, the control unit 7 determines that "etching stoppage has been avoided", thus sets the oxygen flow rate back to the original flow rate. This operation is repeated during the preset time. COPYRIGHT: (C)2008,JPO&INPIT |
