A radio communications module includes high-frequency component chips (4) which are flip-chip mounted by means of bumps (4a) on a thin-film multilayer substrate (2) having a metallic base (2a) and a dielectric layer (26) of low dielectric constant. The chips may be mounted in recesses in said substrate or mounted on a tape carrier package. By bonding chips via solder bumps to a metal-based thin-film multilayer substrate, mounting density is increased to achieve a small size, and wiring loss, consumption of power and noise can be reduced.
