Semiconductor package assembly

1. A semiconductor package assembly, comprising:

a first semiconductor package, comprising:

a first redistribution layer (RDL) structure having a first surface and a second surface opposite to the first surface;

a first semiconductor die disposed on the first surface of the first RDL structure and electrically coupled to the first RDL structure; and

a molding compound overlying the first semiconductor die and the first surface of the first RDL structure; and

a second semiconductor package overlying a portion of the first semiconductor package, comprising:

a first memory die; and

a second memory die vertically stacked on the first memory die, wherein the second memory die is electrically coupled to first memory die by through silicon via (TSV) interconnects formed passing through the second memory die,

wherein a boundary of the second semiconductor package is surrounded by a boundary of the molding compound of the first semiconductor package from a plan view.

2. The semiconductor package assembly as claimed in claim 1 , wherein the first semiconductor package comprises first conductive structures electrically coupled to the first RDL structure, and the second semiconductor package comprises second conductive structures electrically coupled to the first RDL structure.

3. The semiconductor package assembly as claimed in claim 2 , wherein each of the first conductive structures of the first semiconductor package has a first diameter, each of the second conductive structures of the second semiconductor package has a second diameter that is less than the first diameter.

4. The semiconductor package assembly as claimed in claim 2 , wherein the first conductive structures of the first semiconductor package are periodically arranged with a first pitch, and the second conductive structures of the second semiconductor package are arranged with a second pitch that is less than the first pitch.

5. The semiconductor package assembly as claimed in claim 2 , further comprising:

a base, wherein the first semiconductor package and the second semiconductor package are mounted on the base through the first conductive structures of the first semiconductor package.

6. The semiconductor package assembly as claimed in claim 5 , wherein the second semiconductor package embedded in the base, the first conductive structures of the first semiconductor package and the second conductive structures of the second semiconductor package are in contact with the second surface of the first RDL structure.

7. The semiconductor package assembly as claimed in claim 5 , further comprising:

a heat sink structure overlying the first semiconductor package and the second semiconductor package, wherein the heat sink structure is connected to the base to form a space for accommodating the first semiconductor package and the second semiconductor package.

8. The semiconductor package assembly as claimed in claim 7 , wherein the heat sink structure comprises;

a ring portion connected to the base and surrounding the first semiconductor package and the second semiconductor package; and

a cover portion covering the first semiconductor package and the second semiconductor package and connected to the ring portion.

9. The semiconductor package assembly as claimed in claim 2 , wherein the second semiconductor package is coupled to the first RDL structure by first vias passing through the molding compound of the first semiconductor package.

10. The semiconductor package assembly as claimed in claim 9 , wherein the first semiconductor package comprises:

a second redistribution layer (RDL) structure over the molding compound and separated from the first RDL structure through the molding compound, wherein the first vias are electrically coupled to the second RDL structure.

11. The semiconductor package assembly as claimed in claim 10 , wherein pads of the first semiconductor die are electrically coupled to the first RDL structure through second vias between the first semiconductor die and the first surface of the first RDL structure.

12. The semiconductor package assembly as claimed in claim 10 , wherein the second semiconductor package comprises second conductive structures, wherein the second conductive structures and the molding compound are respectively in contact with opposite surfaces of the second RDL structure.

13. The semiconductor package assembly as claimed in claim 1 , wherein the first semiconductor package comprises:

a second semiconductor die next to the first semiconductor die and electrically coupled to the RDL structure.

14. A semiconductor package assembly, comprising:

a first semiconductor package, comprising:

a first redistribution layer (RDL) structure having a first surface and a second surface opposite to the first surface;

a logic die electrically coupled to the first RDL structure; and

a molding compound overlying the logic die and the first surface of the first RDL structure; and

a second semiconductor package stacked on the first semiconductor package, comprising:

a plurality of memory dies stacked one on top of the other, wherein each of the plurality of memory dies has through silicon via (TSV) interconnects,

wherein a boundary of the second semiconductor package is surrounded by a boundary of the molding compound of the first semiconductor package from a plan view.

15. The semiconductor package assembly as claimed in claim 14 , wherein the first semiconductor package comprises:

first conductive structures electrically coupled to the first RDL structure, wherein the first conductive structures are spaced apart from the logic die through the first RDL structure.

16. The semiconductor package assembly as claimed in claim 15 , further comprising:

a base electrically coupled to the first semiconductor package and the second semiconductor package, wherein a boundary of the base surrounds the boundary of the molding compound of the first semiconductor package and the boundary of the second semiconductor package from the plan view.

17. The semiconductor package assembly as claimed in claim 16 , wherein the logic die having pads positioned between a front side of the logic die and the first surface of the first RDL structure.

18. The semiconductor package assembly as claimed in claim 16 , wherein the second semiconductor package is positioned between the second surface of the first RDL structure of the first semiconductor package and the base.

19. The semiconductor package assembly as claimed in claim 16 , wherein the first semiconductor package comprises:

a second redistribution layer (RDL) structure over the molding compound, wherein the first RDL structure and the second RDL structure are in contact with opposite surfaces of the molding compound of the first semiconductor package; and

first vias passing through the molding compound of the first semiconductor package, wherein the first vias are electrically coupled to the first RDL structure and the second RDL structure.

20. The semiconductor package assembly as claimed in claim 19 , wherein the second semiconductor package and the first vias are positioned overlying opposite surfaces of the second RDL structure.

21. The semiconductor package assembly as claimed in claim 20 , wherein the first conductive structures are positioned on the first surface of the first RDL structure and electrically coupled to the first RDL structure through first vias passing through the molding compound of the first semiconductor package.

22. The semiconductor package assembly as claimed in claim 19 , wherein the second semiconductor package is spaced apart from the first conductive structures through the first RDL structure, the first vias and the second RDL structure.

23. The semiconductor package assembly as claimed in claim 22 , wherein the logic die and the second semiconductor package are positioned overlying the first surface and the second surface of the first RDL structure, respectively.

24. The semiconductor package assembly as claimed in claim 16 , further comprising:

a heat sink structure overlying the first semiconductor package and the second semiconductor package, wherein the heat sink structure is connected to the base to form a space for accommodating the first semiconductor package and the second semiconductor package.

25. A semiconductor package assembly, comprising:

a system-on-chip (SOC) package, comprising:

a first redistribution layer (RDL) structure;

a logic die electrically coupled to the first RDL structure; and

a molding compound overlying the logic die and the first RDL structure; and

a memory package stacked on the SOC package, comprising:

a plurality of memory dies stacked one on top of the other, wherein each of the plurality of memory dies has through silicon via (TSV) interconnects rather than RDL structures,

wherein the memory package is positioned overlying a portion of the molding compound of the SOC package,

wherein a boundary of the memory package is surrounded by a boundary of the molding compound from a plan view.

26. The semiconductor package assembly as claimed in claim 25 , wherein the SOC package comprises:

first conductive structures electrically coupled to the first RDL structure; and

a base in contact with the first conductive structures and electrically coupled to the first semiconductor package and the second semiconductor package, and wherein the memory package is embedded in the base and surrounded by the first conductive structures of the SOC package.