Method for producing a coil integrated in a substrate or applied to a substrate, and electronic device

The subject matter of the invention relates to a method of producing a coil integrated in a substrate, using the following steps: creating the cavity in a substrate, said cavity having an open end which interrupts a surface of the substrate, introducing a paste containing ferromagnetic particles into the cavity so as to produce a coil core, closing the cavity by applying a cover layer so as to bridge the interruption in the surface of the substrate, introducing first winding portions of the coil which are vertical with respect to the surface, with a plurality or all of the first winding portions passing through the coil core contained inside the cavity, and applying second winding portions of the coil onto the surfaces of the substrate, with the second winding portions contacting the first winding portions so as to create the windings of the coil.