Method of forming surface treatment film

A method of forming a surface treatment film, comprising preparing a substrate having, on a surface thereof, a first region where an insulator is exposed and a second region where at least one metallic matter selected from a metal or a conductive metal-containing compound is exposed,

• oxidizing a surface of the second region, and
• exposing the surface of the substrate after the oxidizing to a surface-treatment agent comprising a thiol having 8 or fewer carbon atoms to form the surface treatment film on the second region, wherein the surface treatment film has a thickness of 10 nm or more, and
• wherein the formation of the surface treatment film is configured to suppress an overhang of a second insulator formed on the insulator deposited on the first region.