Film deposition method

A film deposition method for filling a recessed pattern formed in a surface of a substrate with a SiN film, comprising steps of:

• causing NH2 groups to adsorb on a surface of a substrate containing a recessed pattern formed in a top surface of the substrate by supplying a first process gas containing NH3 converted to first plasma to the surface of the substrate containing the recessed pattern;
• partially converting the NH2 groups to N groups by supplying a second process gas containing N2 converted to second plasma to the surface of the substrate containing the recessed pattern on which the NH2 groups is adsorbed;
• and
• causing a silicon-containing gas to adsorb on the NH2 groups by supplying the silicon-containing gas to the surface of the substrate containing the recessed pattern on which the NH2 groups and the N groups are adsorbed;
• and
• cyclically repeating the steps of causing the NH2 groups to adsorb on the surface of the substrate, partially converting the NH2 groups to the N groups and causing the silicon-containing gas to adsorb on the NH2 groups,
• wherein the first plasma is generated at a first height higher and more distant from the top surface of the substrate than a second height at which the second plasma is generated, the first height being set at a height that causes the first plasma containing NH3 to reach a bottom of the recessed pattern, the second height being set at a height that causes the second plasma containing N2 to reach only an upper portion of the recessed pattern and the top surface of the substrate.