Method for producing electronic component mounted substrate

A method for manufacturing an electronic-component-mounted substrate, the method comprising:

• a step (i) of forming a temporary fixing film in such a manner as to cover a plurality of solder precoats formed on a plurality of lands on a substrate and an antioxidation film formed in such a manner as to cover each of the plurality of solder precoats;
• a step (ii) of disposing a plurality of electronic components on the plurality of solder precoats via the antioxidation film and the temporary fixing film;
• and
• a step (iii) of soldering the plurality of electronic components to the plurality of lands by melting the plurality of solder precoats,
• wherein the antioxidation film contains a first thermoplastic resin,
• the temporary fixing film contains an activating agent and a second thermoplastic resin,
• a softening point of the first thermoplastic resin is lower than a softening point of the second thermoplastic resin,
• the method further comprising, before the step (i), a step (x) of forming the plurality of solder precoats and the antioxidation film on the plurality of lands,
• the antioxidation film is a residue formed on a surface of the solder precoats when the plurality of solder precoats are formed in the step (x).