One subject of the present invention is a non-electrochemical process for radical grafting of a polymer to a solid, organic or inorganic and insulating, electrically conductive or electrically semiconductive substrate, which process comprises - bringing said substrate into contact with the polymer in solution via an immersion-emersion, a contact coating, or a spray coating, and - heat treating the polymer-covered substrate obtained in the preceding step at a temperature between 70°C and 450°C; said polymer not being a polymer based on acrylic acid. The invention also relates to a process for metallizing the solid, organic or inorganic substrate coated by the polymer film, which metallizing may be carried out via a dry or wet route. This process particularly finds an application in the metallization of through vias for the manufacture of semiconductor devices.