A substrate is provided with electrical connection pads on a front face and on a rear face, the front pads and rear pads being selectively connected via a network passing through the substrate. A peripheral edge of the substrate is mounted on a rigid annular frame and the rearm face secured to a suction table. A layer of a dielectric sealant containing electrically conductive particles is deposited on the front face and front pads of the substrate. Integrated-circuit chips are positioned on the front face to flatten the layer of dielectric sealant, the included electrically conductive particles making electrical connection between pads of the integrated-circuit and the front pads of the substrate. The resulting assembly in then encapsulated in a block of encapsulating material positioned on top of the front face of the substrate. The block is then diced in order to obtain a plurality of semiconductor packages.