Plasma processing method

A plasma processing apparatus, comprising:

• a chamber having at least one inlet for a first gas and a second gas;
• a substrate support disposed in the chamber, the substrate support having a surface for supporting a substrate, the surface having a first region and a second region surrounding the first region;
• a lower electrode disposed in the substrate support;
• a first RF power supply configured to supply a first RF signal having a first frequency;
• a second RF power supply electrically connected to the lower electrode and configured to supply a second RF signal having a second frequency, the second frequency being lower than the first frequency;
• an electromagnet configured to form a magnetic field in the chamber, the magnetic field having a first component on the first region and a second component on the second region, a magnitude of the second component being greater than a magnitude of the first component;
• and
• a controller configured to cause:
• a) placing a substrate on the substrate support;
• b) forming a first plasma from the first gas in the chamber with at least the first RF signal, and wherein during forming of the first plasma, the second RF signal is supplied to the lower electrode at a first power level, the first power level being equal to or greater than zero;
• c) exposing the substrate to the first plasma;
• d) forming a second plasma from the second gas in the chamber with the first and second RF signals and the magnetic field, and wherein during forming of the second plasma, the second RF signal is supplied to the lower electrode at a second power level greater than the first power level;
• and
• e) exposing the substrate to the second plasma.