High density integrated circuit package assembly with a heatsink between stacked dies

• US 5,739,581 A
• Filed: 11/17/1995
• Issued: 04/14/1998
• Est. Priority Date: 11/17/1995
• Status: Expired due to Term

• Current Assignee: National Semiconductor Corporation (Texas Instruments, Inc.)
• Original Assignee: National Semiconductor Corporation (Texas Instruments, Inc.)
• Inventors: Mostafazadeh, Shahram, Chillara, Satya
• Primary Examiner(s): Thomas, Tom
• Assistant Examiner(s): OSTROWSKI, DAVID M
• Application Number:
  US08/560,280
• Time in Patent Office: 879 Days
• Field of Search: 257/686, 257/723, 257/724, 257/725, 257/668, 257/675, 257/693, 257/700, 257/701, 257/706, 257/737, 257/738, 257/778, 257/784
• US Class Current: 257/668
• CPC Class Codes: H01L 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/32245 the item being metallic
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/49109 outside the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2225/0651 Wire or wire-like electrical connections from device to substrate
• CPC Class Codes: H01L 2225/06575 Auxiliary carrier between devices, the carrier having no electrical connection structure
• CPC Class Codes: H01L 2225/06582 Housing for the assembly, e.g. chip scale package [CSP]
• CPC Class Codes: H01L 2225/06586 Housing with external bump or bump-like connectors
• CPC Class Codes: H01L 24/73 Means for bonding being of different types provided for in two or more of groups H01L24/10, H01L24/18, H01L24/26, H01L24/34, H01L24/42, H01L24/50, H01L24/63, H01L24/71
• CPC Class Codes: H01L 25/0657 Stacked arrangements of devices
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• CPC Class Codes: H01L 2924/01322 Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases
• CPC Class Codes: H01L 2924/14 Integrated circuits
• CPC Class Codes: H01L 2924/15311 being a ball array, e.g. BGA
• CPC Class Codes: H01L 2924/16152 : Cap comprising a cavity for hosting the device, e.g. U-shaped cap
• CPC Class Codes: H01L 2924/1627 : stacked type assemblies, e.g. stacked multi-cavities

Abstract

An integrated circuit package assembly with a first die disposed over a first substrate having traces defined therein to provide electrical access to the first die. A heatsink is disposed over the substrate and the first die. A second die and a leadframe is disposed over the heatsink. The leadframe provides electrical access to the second die.

Claims

1. An integrated circuit (IC) package assembly for supporting dies and providing access to dies, the package assembly comprising:

a substrate having a top surface, a bottom surface and a plurality of first traces from the top surface to the bottom surface;

a first die disposed over the top surface of the substrate and electrically connected to the first traces at the top surface of the substrate;

a heatsink having a top surface and a bottom surface, with the bottom surface of the heatsink disposed over the top surface of the substrate and over the first die;

a leadframe having a plurality of leadframe leads, with the leadframe disposed over the top surface of the heatsink; and

a second die disposed over the top surface of the heatsink and electrically connected to the leads of the leadframe.

2. The package assembly according to claim 1, further comprising a plurality of solder balls respectively connected to each of the plurality of first traces at the bottom surface of the substrate.

3. The package assembly according to claim 1, further comprising a lid that at least partially covers the package assembly.

4. The package assembly according to claim 1, further comprising an over-mold that at least partially covers the package assembly.

5. The package assembly according to claim 1, wherein the package assembly is at least partially covered by an encapsulant.

6. The package assembly according to claim 1, wherein the heatsink has a cavity defined in its bottom surface for accommodating the first die.

7. The package assembly according to claim 6, further comprising:

a plurality of bonding wires for electrically connecting the first die to the traces at the top surface of the substrate; and

wherein the cavity has a depth measured from the bottom surface of the heatsink which is greater than a combined height of a thickness of the first die and a wire bond loop height of the bonding wires.

8. The package assembly according to claim 1, wherein the heatsink is made of anodized aluminum.

9. The package assembly according to claim 1, wherein the heatsink is made of copper.

10. The package assembly according to claim 1, wherein the heatsink is made of ceramic.

11. The package assembly according to claim 1, further comprising a layer of insulating material between at least a portion of the top surface of the substrate and at least a portion of the bottom surface of the heatsink.

12. The package assembly according to claim 11, wherein the layer of insulating material is made of adhesive insulating tape.

13. The package assembly according to claim 11, wherein the layer of insulating material is made of non-conductive epoxy.

14. The package assembly according to claim 1, further comprising a layer of insulating material between at least a portion of the top surface of the heatsink and at least a portion of the leadframe.

15. The package assembly according to claim 14, wherein the layer of insulating material is made of adhesive insulating tape.

16. The package assembly according to claim 14, wherein the layer of insulating material is made of non-conductive epoxy.

17. The package assembly according to claim 1, further comprising:

a first layer of insulating material between at least a portion of the top surface of the substrate and at least a portion of the bottom surface of the heatsink; and

a second layer of insulating material between at least a portion of the top surface of the heatsink and at least a portion of the leadframe.

18. The package assembly according to claim 1, wherein the bottom surface of the heatsink is disposed on the top surface of the substrate.

19. The package assembly according to claim 1, wherein the leadframe is disposed on the top surface of the heatsink.

20. The package assembly according to claim 1, wherein at least one of the plurality of first traces runs from the top surface of the substrate to the bottom surface of the substrate through a via defined in the substrate.

21. The package assembly according to claim 1, wherein at least one of the plurality of first traces runs from the top surface of the substrate to the bottom surface of the substrate by running around a peripheral edge of the substrate.

22. The package assembly according to claim 1, wherein the first die is connected to the first traces by tape automated bonding.

23. The package assembly according to claim 1, wherein the first die is connected to the first traces by flip chip bonding.

24. The package assembly according to claim 1, further comprising bonding wires for connecting the first die to the first traces by wirebonding.

25. The package assembly according to claim 1, wherein the second die is connected to the leadframe by tape automated bonding.

26. The package assembly according to claim 1, wherein the second die is connected to the leadframe by flip chip bonding.

27. The package assembly according to claim 1, further comprising bonding wires for connecting the second die to the leadframe by wirebonding.

28. The package assembly according to claim 1, wherein:

the heatsink has a plurality of second traces from the top surface of the heatsink to the bottom surface of the heatsink;

the substrate has a plurality of third traces from the top surface of the substrate to the bottom surface of the substrate; and

the second traces of at the bottom surface of the heatsink respectively contact third traces at the top surface of the substrate; and

the second die is electrically connected to the second traces at the top surface of the heatsink.

29. The package assembly according to claim 1, further comprising:

an insulating layer disposed on at least a portion of the leadframe; and

a conductive plane disposed on the insulating layer, the second die being electrically connected to the conductive plane.

30. The package assembly according to claim 29, wherein the conductive plane is a power plane.

31. The package assembly according to claim 29, wherein the conductive plane is a ground plane.

32. An integrated circuit (IC) package assembly for supporting dies and providing access to dies, the package assembly comprising:

a first substrate having a top surface, a bottom surface and a plurality of first traces from the top surface to the bottom surface;

a first die disposed over the top surface of the first substrate and electrically connected to the first traces at the top surface of the first substrate;

a heatsink having a top surface and a bottom surface, with the bottom surface of the heatsink disposed over the top surface of the first substrate and the first die;

a second substrate having a top surface, a bottom surface, and a plurality of second traces, with the bottom surface of the second substrate disposed over the top surface of the heatsink;

a leadframe electrically connected to the second traces; and

a second die disposed on the top surface of the second substrate and electrically connected to the second traces.

33. An integrated circuit (IC) package assembly for supporting dies and providing access to dies, the package assembly comprising:

a first substrate having a top surface, a bottom surface and a plurality of traces from the top surface to the bottom surface;

a first die disposed over the top surface of the first substrate and electrically connected to the first traces at the top surface of the first substrate;

a heatsink having a top surface and a bottom surface, with the bottom surface of the heatsink disposed over the top surface of the first substrate and the first die;

a second substrate having an integrated leadframe, a top surface and a bottom surface, with the bottom surface of the second substrate disposed over the top surface of the heatsink; and

a second die disposed on the top surface of the second substrate and electrically connected to the second traces.

34. An integrated circuit (IC) package assembly for supporting dies and providing access to dies, the package assembly comprising:

a substrate having a top surface, a bottom surface and a plurality of first traces from the top surface to the bottom surface;

a first die disposed on the top surface of the substrate and electrically connected to the first traces at the top surface of the substrate;

a heatsink having a top surface and a bottom surface, and a plurality of second traces, with the bottom surface of the heatsink disposed over the top surface of the substrate and the first die;

a second die disposed over the top surface of the heatsink and electrically connected to the second traces; and

a leadframe electrically connected to the second traces.

35. The package assembly according to claim 34, wherein the traces of heatsink comprise a thin film located at the top surface of the heatsink which is made by thin film techniques.