Package-on-package semiconductor assemblies and methods of manufacturing the same

1. A package-on-package system, comprising:

a first semiconductor device package having—

a base substrate including a first side having a die-attach region and a perimeter region;

a first semiconductor die attached to the base substrate at the die-attach region, wherein the first semiconductor die has a front side facing the first side of the base substrate and a backside spaced apart from the first side of the base substrate by a first distance; and

a high density interconnect array over the perimeter region of the base substrate and outside of the die-attach region, wherein the interconnect array has a plurality of interconnects and extends from the first side of the base substrate by a second distance greater than the first distance, wherein the interconnect array comprises a first interconnect structure at the first side of the base substrate and a plurality of additional interconnect structures stacked over the first interconnect structure, and wherein individual interconnect structures include a stratum of a matrix material and a plurality of interconnect segments arranged in a pattern of the interconnect array; and

a second semiconductor device package having—

an interposer substrate having a top side, a bottom side, and a plurality of package terminals at the bottom side, wherein individual package terminals are electrically coupled to corresponding individual interconnects; and

a second semiconductor die attached to the top side of the interposer substrate.

2. The system of claim 1 wherein the interconnects of the interconnect array comprise a plurality of freestanding conductive posts spaced apart from each other by open gaps.

3. The system of claim 2 wherein the conductive posts comprise copper.

4. The system of claim 1 wherein the first semiconductor die is electrically connected to the second semiconductor die via the interconnect array.

5. The system of claim 1 wherein top surfaces of the stratum of matrix material and top surfaces of the individual interconnect segments of the individual interconnect structures are co-planar.

6. The system of claim 1 wherein individual interconnect segments of the individual interconnect structures are separated from one another by a distance less than 300 micrometers.

7. The system of claim 1 wherein the base substrate includes circuitry, and wherein each of the interconnects of the interconnect array is electrically coupled to the circuitry of the base substrate.

8. A package-on-package system, comprising:

a first semiconductor device package including—

a base substrate having a die-attach region;

a dielectric structure on the base substrate and comprising a plurality of stratums of a matrix material, and wherein the dielectric material has a cavity aligned with the die-attach region and a mounting surface at an elevation;

a first semiconductor die attached to the die-attach region of the base substrate and electrically coupled to the base substrate, wherein the first semiconductor die has a height relative to the base substrate that is less than the elevation of the mounting surface of the dielectric structure; and

a high density interconnect array outside the die-attach region and extending through the dielectric structure and being exposed at the mounting surface, wherein the interconnect array includes individual interconnects electrically coupled to the base substrate; and

a second semiconductor device package having—

an interposer substrate having a top side, a bottom side, and a plurality of package terminals at the bottom side, wherein individual package terminals are electrically coupled to one of the interconnects; and

a second semiconductor die attached to the top side of the interposer substrate.

9. The system of claim 8 wherein individual interconnects of the interconnect array comprise a plurality of interconnect segments in the stratums of the matrix material that are aligned along a common line normal to the front side of the base substrate.

10. The system of claim 8 wherein the base substrate further includes a perimeter region peripheral to the die attach region, and wherein the interconnect array is over the perimeter region.

11. The system of claim 8 wherein the first semiconductor die is electrically connected to the second semiconductor die via the interconnect array.

12. The system of claim 8 wherein the interconnects of the interconnect array comprise a plurality of freestanding conductive copper posts.