Method of processing substrate, method of manufacturing semiconductor device, recording medium, and substrate processing apparatus

A substrate processing apparatus comprising:

• a source supplier configured to supply a source containing a predetermined element, carbon, and hydrogen to a substrate;
• a first modifying agent supplier configured to supply a first modifying agent containing nitrogen to the substrate;
• a second modifying agent supplier configured to supply, to the substrate, a second modifying agent that is different from the first modifying agent and contains a compound containing a nitrogen-hydrogen bond and a nitrogen-nitrogen bond per molecule or a derivative of the compound;
• and
• a controller configured to be capable of controlling the source supplier, the first modifying agent supplier, and the second modifying agent supplier to perform processing including:
• (a) performing a cycle including supplying the source to the substrate and supplying the first modifying agent to the substrate, a predetermined number of times to form, on the substrate, a first film containing the predetermined element, nitrogen, carbon, and hydrogen bonded to carbon;
• and
• (b) supplying, to the substrate on which the first film is formed, the second modifying agent to modify the first film to a second film that is lower in content rate of the hydrogen bonded to carbon than the first film and contains the predetermined element, carbon, and nitrogen.