Packaging architecture with thermally conductive integrated circuit bridge
Embodiments of a microelectronic assembly comprises a first layer, a second layer and a third layer in a stack; a package substrate in the first layer, the package substrate comprising a metallic via structure; a first integrated circuit (IC) die surrounded by an organic dielectric material in the second layer, the first IC die coupled to the package substrate; a second IC die in the third layer, the second IC die coupled to the first IC die; and a third IC die in the third layer, the third IC die coupled to the first IC die. An electrically conductive pathway in the first IC die electrically couples the third IC die and the second IC die, and the first IC die is coupled to the package substrate with a thermally conductive material in contact with the metallic via structure in the package substrate.
1 . A microelectronic assembly, comprising:
a first layer, a second layer, and a third layer in a stack, the second layer between the first layer and the third layer;
a package substrate in the first layer, the package substrate having a first side and a second side opposite to the first side, the package substrate comprising a metallic via structure extending between the first side and the second side of the package substrate;
a first integrated circuit (IC) die surrounded by an organic dielectric material in the second layer, the first IC die coupled to the package substrate;
a second IC die in the third layer, the second IC die coupled to the first IC die; and
a third IC die in the third layer, the third IC die coupled to the first IC die,
wherein:
an electrically conductive pathway in the first IC die electrically couples the third IC die and the second IC die, and
the first IC die is coupled to the package substrate with a thermally conductive material in contact with the metallic via structure in the package substrate, wherein the thermally conductive material comprises graphite and the graphite is enclosed within a ring of adhesive material between the first IC die and the package substrate.
2 . The microelectronic assembly of claim 1 , wherein the metallic via structure is electrically isolated from electrical circuits in the package substrate.
3 . The microelectronic assembly of claim 1 , wherein a surface of the first IC die in contact with the thermally conductive material comprises a coating of copper.
4 . The microelectronic assembly of claim 1 , wherein:
the metallic via structure is coupled to a thermally conductive interconnect on a surface of the package substrate opposite to the first IC die, and
the thermally conductive interconnect is not connected to any electrical pathway.
5 . The microelectronic assembly of claim 1 , wherein the package substrate is coupled to a printed circuit board (PCB) opposite to the first IC die.
6 . The microelectronic assembly of claim 1 , wherein the graphite extends through an opening in the ring beyond a perimeter of the first IC die.
7 . The microelectronic assembly of claim 1 , wherein the thermally conductive material extends beyond a boundary of the first IC die.
8 . The microelectronic assembly of claim 1 , wherein the organic dielectric material comprises mold compound.
9 . The microelectronic assembly of claim 1 , further comprising:
through-mold vias (TMVs) through the organic dielectric material.
10 . The microelectronic assembly of claim 9 , wherein the metallic via structure has a larger diameter than the TMVs.
11 . An IC die, comprising:
a substrate; and
a metallization stack parallel and adjacent to the substrate,
wherein:
the metallization stack comprises electrically conductive pathways,
a first side of the IC die proximate to the metallization stack is coupled to at least two other IC dies by die-to-die (DTD) interconnects,
a second side of the IC die opposite to the first side is coupled to a package substrate having thermal vias extending through a thickness of the package substrate,
the IC die is surrounded on its remaining sides by an organic dielectric material, and
a thermally conductive material is between the second side of the IC die and the package substrate and in contact with the thermal vias, wherein:
the thermally conductive material comprises graphite and an adhesive material,
the IC die is attached to the package substrate by the adhesive material,
the adhesive material forms a ring along a periphery of the IC die, and
the graphite is enclosed within the ring of the adhesive material.
12 . The IC die of claim 11 , wherein the thermally conductive material is a first thermally conductive material, and the IC die further comprising:
through-substrate vias (TSVs) in the substrate, wherein:
the TSVs comprise a second thermally conductive material different than the first thermally conductive material, and
the TSVs are electrically isolated from electrical circuits in the IC die.
13 . The IC die of claim 11 , wherein the at least two other IC dies are electrically coupled by the DTD interconnects and the electrically conductive pathways.
14 . The IC die of claim 11 , wherein the package substrate comprises a thermally conductive pad in contact with the thermal vias.
15 . The IC die of claim 14 , wherein:
the thermally conductive pad comprises a metal,
the second side of the IC die comprises a coating of the metal, and
the thermally conductive pad is attached to the coating.
16 . The IC die of claim 12 , wherein the second thermally conductive material comprises copper.
17 . A method for fabricating a microelectronic assembly, the method comprising:
providing a package substrate having a first surface, an opposing second surface, and at least one thermal via through the package substrate between the first surface and the second surface such that a portion of the thermal via is exposed on the first surface;
depositing a thermally conductive material on the exposed portion of the thermal via, wherein depositing the thermally conductive material comprises:
applying an adhesive paste or film in a shape of a ring around the exposed portion of the thermal via, the ring having an inner perimeter and an outer perimeter; and
placing a sheet of graphite within the inner perimeter such that the graphite is in contact with the exposed portion of the thermal via;
depositing electrically conductive traces and conductive pillars on the first surface;
coupling a first IC die to the thermally conductive material;
depositing an organic dielectric on the first surface around the first IC die, the conductive traces and the conductive pillars;
exposing contact pads on the first IC die opposite to the package substrate; and
coupling a second IC die and a third IC die to the contact pads, wherein at least one conductive pathway in the first IC die electrically couples the second IC die and the third IC die.
18 . The method of claim 17 , further comprising:
exposing a surface of the conductive pillars on a side of the organic dielectric opposite to the package substrate; and
coupling the second IC die and the third IC die to the exposed surfaces of the conductive pillars,
wherein:
the second IC die and the third IC die are coupled to the first IC die with first interconnects of a first pitch between adjacent first interconnects,
the second IC die and the third IC die are coupled to the conductive pillars with second interconnects of a second pitch between adjacent second interconnects, and
the first pitch is smaller than the second pitch.
19 . The method of claim 17 , wherein coupling the first IC die to the thermally conductive material comprises:
attaching the first IC die to the adhesive paste or film such that the graphite is between the first IC die and the thermal via.
20 . The method of claim 17 , further comprising:
coupling a printed circuit board (PCB) to interconnects of the package substrate, wherein the interconnects are on a side of the package substrate opposite to the first IC die, at least one interconnect is in contact with the thermal via, and the at least one interconnect is electrically isolated from other interconnects.