Method of manufacturing semiconductor devices and corresponding semiconductor device
A semiconductor chip or die is arranged on a first surface of a thermally conductive die pad of a substrate such as a leadframe. An encapsulation of insulating material in molded onto the die pad having the semiconductor die arranged on the first surface. At the second surface of the die pad, opposite the first surface, the encapsulation borders on the die pad at a borderline around the die pad. A recessed portion of the encapsulation is provided, for example, via laser ablation, at the borderline around the die pad. Thermally conductive material such as metal material is filled in the recessed portion of the encapsulation around the die pad. The surface area of the thermally conductive die pad is augmented by the filling of thermally conductive material in the recessed portion of the encapsulation thus improving thermal performance of the device.
1 . A method, comprising:
arranging a semiconductor integrated circuit die on a first surface of a thermally conductive die pad of a lead frame, the thermally conductive die pad having a second surface opposite the first surface;
molding an encapsulation of insulating material onto the thermally conductive die pad, wherein, at the second surface of the thermally conductive die pad, the encapsulation borders on the thermally conductive die pad at a borderline around the thermally conductive die pad;
removing insulating material from the encapsulation molded onto the thermally conductive die pad at said borderline around the thermally conductive die pad to provide a recessed portion of the encapsulation around the thermally conductive die pad; and
filling thermally and electrically conductive material in said recessed portion of the encapsulation;
wherein a surface area of the thermally conductive die pad at said second surface is augmented by thermally and electrically conductive material in said recessed portion of the encapsulation.
2 . The method of claim 1 , wherein filling thermally and electrically conductive material comprises one of:
jet printing thermally and electrically conductive material at said recessed portion;
plating thermally and electrically conductive material at said recessed portion; or
laser-induced forward transfer of thermally and electrically conductive material at said recessed portion.
3 . The method of claim 1 , wherein removing comprises applying laser beam energy to the encapsulation.
4 . The method of claim 1 , wherein the insulating material of the encapsulation comprises laser direct structuring (LDS) material, and wherein removing comprises applying a laser structuring to the LDS material of the encapsulation at said borderline around the thermally conductive die pad.
5 . The method of claim 4 , wherein the LDS material of the encapsulation has a front surface opposite the thermally conductive die pad, and further comprising:
structuring, in the LDS material of the encapsulation, through-mold vias extending into the encapsulation from said front surface; and
structuring, in the LDS material of the encapsulation, connecting lines extending over said front surface between selected ones of the through-mold vias.
6 . The method of claim 5 , further comprising:
applying laser beam energy to the LDS material of the encapsulation at candidate locations for said through-mold vias and connecting lines; and
subsequent to applying laser beam energy, filling electrically conductive material at said candidate locations to provide electrically conductive through-mold vias and connecting lines at said candidate locations.
7 . The method of claim 6 , wherein filling electrically conductive material comprises:
plating electrically conductive material at said candidate locations; or
laser-induced forward transfer of thermally conductive material at said candidate locations.
8 . The method of claim 1 wherein the thermally and electrically conductive material filled in said recessed portion of the encapsulation has a thickness different from the thickness of the thermally conductive die pad.
9 . The method of claim 1 , wherein said lead frame includes an array of electrically conductive leads surrounding the thermally conductive die pad, and wherein the electrically conductive leads project above the thermally and electrically conductive material filled in said recessed portion of the encapsulation.
10 . The method of claim 1 , wherein said thermally conductive die pad is made of an electrically conductive material.
11 . A method, comprising:
arranging a semiconductor integrated circuit die on a first surface of a thermally conductive die pad of a lead frame, the thermally conductive die pad having a second surface opposite the first surface;
molding an encapsulation of insulating material onto the thermally conductive die pad;
wherein a bottom surface of the encapsulation and the second surface of the thermally conductive die pad are coplanar;
removing insulating material of the encapsulation from the bottom surface of the encapsulation at a borderline around the thermally conductive die pad to form a recessed portion of the encapsulation around the thermally conductive die pad; and
filling the recessed portion with a thermally and electrically conductive material to augment a surface area of the thermally conductive die pad at the bottom surface of the encapsulation;
wherein the thermally and electrically conductive material filling the recessed portion has a bottom surface coplanar with both the bottom surface of the encapsulation and the second surface of the thermally conductive die pad.
12 . The method of claim 11 , wherein filling thermally and electrically conductive material comprises jet printing thermally and electrically conductive material at said recessed portion.
13 . The method of claim 11 , wherein filling thermally and electrically conductive material comprises plating thermally and electrically conductive material at said recessed portion.
14 . The method of claim 11 , wherein filling thermally and electrically conductive material comprises laser-induced forward transfer of thermally and electrically conductive material at said recessed portion.
15 . The method of claim 11 , wherein the insulating material of the encapsulation comprises laser direct structuring (LDS) material, and wherein removing comprises applying a laser structuring to the LDS material of the encapsulation at said borderline around the thermally conductive die pad.
16 . The method of claim 15 , wherein filling thermally and electrically conductive material comprises plating thermally and electrically conductive material at said recessed portion in the laser structured LDS material.
17 . The method of claim 11 , wherein the thermally and electrically conductive material filled in said recessed portion of the encapsulation has a thickness different from the thickness of the thermally conductive die pad.
18 . The method of claim 11 , wherein said lead frame includes an array of electrically conductive leads surrounding the thermally conductive die pad, and wherein the electrically conductive leads project above the thermally and electrically conductive material filled in said recessed portion of the encapsulation.