Plasma processing method in semiconductor processing system

A method of subjecting a process object to a plasma processing by using a plasma in a semiconductor processing system, comprising:

• a setting step of setting, on the basis of an expected progress of the plasma processing, a measurement target necessary for observing progress of the plasma processing, a designated time period during which the measurement target must be measured, and a sample distribution function necessary for approximating a change in the measurement target;
• a step of starting the plasma processing for the process object after the setting step;
• a measurement step, during the plasma processing, of measuring the measurement target in the designated time period;
• an approximating step, during the plasma processing, of obtaining an approximate equation that approximates the change in the measurement target that takes place along with the progress of the plasma processing, on the basis of measurement data of the measurement target obtained in the measurement step and the sample distribution function;
• an anticipating step, during the plasma processing, of calculating an expected profile of the change in the measurement target after the designated time period and a virtual end point at which the plasma processing should be ended, on the basis of the approximate equation;
• a determination step, during the plasma processing and after the designated time period, of determining whether the plasma processing should be ended on the basis of the virtual end point;
• and
• a step of ending the plasma processing on the basis of a determination result of the determination step.