Apply heat to thermoplastic resin film, which is eventually to become an
insulating resin layer, and press the film against a mold for forming
grooves on a surface of the film. Next, press-fit an electronic component
into the resin film from a back-face of the film, thereby exposing
electrodes of the component from a bottom of the grooves. Then cool the
film for curing. Peel the film off the mold, then fill the grooves with
conductive paste, and cure the paste for forming circuit patterns. The
foregoing procedure allows bringing the electrodes positively into
conduction with the circuit patterns of a circuit board incorporating the
electronic component, and achieving a narrower pitch between routings of
the circuit patterns.