Method for processing workpiece

An apparatus for processing a workpiece comprising:

• a processing chamber provided to accommodate the workpiece;
• a processing gas supply system provided to supply a first gas, a second gas and a third gas into the processing chamber, wherein the first gas contains nitrogen, the second gas does not contain halogen and the third gas contains halogen;
• a high-frequency power source provided to supply a plasma generation high-frequency power into the processing chamber;
• and
• a control unit,
• wherein, on a main surface of the workpiece, a groove is formed,
• wherein the control unit is provided to control the processing gas supply system and the high-frequency power source to execute:
• a first step of accommodating the workpiece in a processing chamber;
• a second step of starting supplying the first gas into the processing chamber after the first step;
• a third step of starting supplying plasma generation high-frequency power into the processing chamber after the second step;
• and
• a fourth step of starting intermittent supplying the second gas into the processing chamber and starting continuous supplying the third gas into the processing chamber together, after the third step.