Integrated circuit comprising: - a substrate that extends mainly in a plane referred to as the "plane of the substrate", this substrate being equipped with electrical connections for electrically connecting the integrated circuit to an exterior electronic circuit and having an interior side; - a top electronic chip (22, 26) and a bottom electronic chip (24; 220), each of these electronic chips being electrically connected to the electrical connections by way of the substrate and each electronic chip comprising a front side turned toward the interior side of the substrate and a back side opposite the front side, the back side of the top electronic chip being located at a height H above the interior side of the substrate and being further from the interior side of the substrate than the back side of the bottom electronic chip; - an encapsulation formed by a thick layer made of an electrically insulating material that coats the electronic chips, this thick layer forming an upper exterior side of the encapsulation parallel to the plane of the substrate; and - a heat sink (60; 150; 222) devoid of electronic components and interposed between the back side of the bottom electronic chip and the upper exterior side of the encapsulation, this sink comprising a front side (62; 152) placed on the back side of the bottom electronic chip and a back side opposite the front side, this back side being comprised between a first and a second plane, which planes are parallel to the plane of the substrate, these first and second planes being located 0.15xH below and 0.15xH above the back side of the top electronic chip, respectively, the thermal conductivity at 25°C of the sink in a direction perpendicular to the plane of the substrate being at least two times higher than the thermal conductivity of the thick layer measured under the same conditions and in the same direction; in which: - the back side of the bottom electronic chip comprises pads; and - the front side of the sink comprises pads that are mechanically fastened to facing pads of the back side of the bottom electronic chip, characterized in that: - the heat sink is electrically insulated from the electronic chips and from the substrate or then electrically connected solely to the ground of the integrated circuit; and - the back side of the heat sink is comprised between a third plane that contains the upper side of the encapsulation and a parallel fourth plane located at least 50 μm under the third plane. - a substrate that extends mainly in a plane referred to as the "plane of the substrate", this substrate being equipped with electrical connections for electrically connecting the integrated circuit to an exterior electronic circuit and having an interior side; - a top electronic chip (22, 26) and a bottom electronic chip (24; 220), each of these electronic chips being electrically connected to the electrical connections by way of the substrate and each electronic chip comprising a front side turned toward the interior side of the substrate and a back side opposite the front side, the back side of the top electronic chip being located at a height H above the interior side of the substrate and being further from the interior side of the substrate than the back side of the bottom electronic chip; - an encapsulation formed by a thick layer made of an electrically insulating material that coats the electronic chips, this thick layer forming an upper exterior side of the encapsulation parallel to the plane of the substrate; and - a heat sink (60; 150; 222) devoid of electronic components and interposed between the back side of the bottom electronic chip and the upper exterior side of the encapsulation, this sink comprising a front side (62; 152) placed on the back side of the bottom electronic chip and a back side opposite the front side, this back side being comprised between a first and a second plane, which planes are parallel to the plane of the substrate, these first and second planes being located 0.15xH below and 0.15xH above the back side of the top electronic chip, respectively, - the back side of the bottom electronic chip comprises pads; and - the front side of the sink comprises pads that are mechanically fastened to facing pads of the back side of the bottom electronic chip, - the heat sink is electrically insulated from the electronic chips and from the substrate or then electrically connected solely to the ground of the integrated circuit; and - the back side of the heat sink is comprised between a third plane that contains the upper side of the encapsulation and a parallel fourth plane located at least 50 μm under the third plane.