Abstract: A technique includes (a) providing a substrate on which a first film containing at least one selected from the group of a combination of C—H bonds and Si—C bonds and a combination of N—H bonds and Si—N bonds is formed, (b) modifying the first film into a second film by performing heat processing to the first film at a processing temperature higher than a processing temperature at which the first film is formed, and (c) modifying the second film into a third film by performing plasma processing to the second film so that a ratio of Si—C bonds to C—H bonds in the third film is made larger than a ratio of Si—C bonds to C—H bonds in the first film, or a ratio of Si—N bonds to N—H bonds in the third film is made larger than a ratio of Si—N bonds to N—H bonds in the first film.

Abstract: There is provided a technique that includes (a) forming a first film on the substrate by supplying a film-forming agent to the substrate; (b) adding oxygen to the first film by supplying a first oxidizing agent to the substrate and oxidizing a part of the first film; and (c) changing the oxygen-added first film into a second film including an oxide film by supplying a second oxidizing agent to the substrate and oxidizing the oxygen-added first film.