Stacked silicon package assembly having an enhanced lid

Patent metadata

Field	Value
Publication number	US-10043730-B2
Application number	US-201514867349-A
Country	US
Kind code	B2
Filing date	Sep 28, 2015
Priority date	Sep 28, 2015
Publication date	Aug 7, 2018
Grant date	Aug 7, 2018

Abstract

A method and apparatus are provided which improve heat transfer between a lid and an IC die of an IC (chip) package. In one embodiment, a chip package is provided that includes a first IC die, a package substrate, a lid and a stiffener. The first IC die is coupled to the package substrate. The stiffener is coupled to the package substrate and circumscribes the first IC die. The lid has a first surface and a second surface. The second surface faces away from the first surface and towards the first IC die. The second surface of the lid is conductively coupled to the IC die, while the lid is mechanically decoupled from the stiffener.

First claim

What is claimed is:

1. A chip package, comprising:
a package substrate;
a first IC die coupled to the package substrate;
a stiffener coupled to the package substrate and circumscribing the first IC die;
a lid having a first surface and a second surface, the second surface facing away from the first surface and towards the first IC die, the second surface of the lid conductively coupled to the first IC die, the lid mechanically decoupled from the stiffener; and
a pin positioning the lid horizontally relative to the stiffener while allowing the lid to float vertically unrestricted relative to the stiffener in a direction normally away from the package substrate, the pin configured to have free and unrestricted engagement and disengagement at least one of the lid and the stiffener.

2. The chip package of claim 1 , wherein the pin extends from the second surface of the lid, the pin engaged in a clearance hole formed through a top surface of the stiffener and having a depth at least as long as the pin, the lid and the pin movable relative to the stiffener.

3. The chip package of claim 1 , wherein the lid further comprises:
a cavity formed therein.

4. The chip package of claim 3 , wherein the cavity is plugged and charged with a captured heat transfer material.

5. The chip package of claim 3 , wherein the lid further comprises:
an inlet port and an outlet port for circulating a heat transfer material through the cavity.

6. The chip package of claim 1 , wherein the lid further comprises:
a plurality of engineered features projecting from at least one of the first or second surfaces of the lid.

7. The chip package of claim 1 further comprising:
a clip securing the lid to the package substrate.

8. The chip package of claim 1 further comprising:
a spring form disposed on the first surface of the lid.

9. The chip package of claim 1 further comprising:
a first spring form compressed between the second surface of the lid and the first IC die.

10. The chip package of claim 9 further comprising:
a second IC die mounted to the package substrate: and
a second spring form compressed between the second surface of the lid and the second IC die.

11. The chip package of claim 9 further comprising:
a second IC die mounted to the package substrate, the second IC die in thermal communication with the second surface of the lid through a low heat transfer rate material disposed therebetween, wherein a heat transfer rate between the second IC die and the second surface of the lid is lower than a heat transfer rate between the first IC die and the second surface of the lid.

12. The chip package of claim 9 further comprising:
a thermal interface material disposed through apertures formed in the first spring form.

13. The chip package of claim 1 further comprising:
a second IC die mounted to the package substrate and outward of the lid.

14. The chip package of claim 13 further comprising:
a heatsink, wherein the first IC die is conductively coupled to the heatsink through the lid while the second IC die is not.

15. The chip package of claim 1 , wherein the lid further comprises:
a plurality of engineered features projecting from at least one of the first or second surfaces of the lid; and
a phase change thermal interface material disposed on the engineered features.

16. A chip package, comprising:
a package substrate;
a first IC die coupled to the package substrate;
a stiffener coupled to the package substrate and circumscribing the first IC die;
a lid having a first surface and a second surface, the second surface facing away from the first surface and towards the first IC die, the second surface of the lid conductively coupled to the first IC die, the lid mechanically decoupled from the stiffener;
a pin extending between the lid and the stiffener, the pin free to move axially in a clearance hole formed through an exposed surface of the stiffener or the second surface of the lid, the clearance hole having a depth at least as long as the pin:
a first spring form compressed between the second surface of the lid and the first IC die;
a second IC die mounted to the package substrate: and
a second spring form compressed between the second surface of the lid and the second IC die, wherein a force provided by the first spring form to the first IC die is different than a force provided by the second spring form to the second IC die.

17. A lid for a chip package, comprising:
a bottom housing having a bottom exterior surface;
a top housing sealingly coupled to the bottom housing; and
a cavity defined between the top and bottom housings; the cavity further comprising:
an inlet zone having a volume expanding in a first lateral direction away from an inlet port, the first lateral direction parallel with the bottom exterior surface of the bottom housing;
an outlet zone having a volume decreasing in a second lateral direction that is opposite the first lateral direction and towards an outlet port, the second lateral direction parallel with the bottom exterior surface of the bottom housing;
a center zone extending in a third direction and connecting the inlet and outlet zones, wherein the first and second lateral directions are perpendicular to and coplanar with the third direction, the third direction parallel with the bottom exterior surface of the bottom housing; and
a plurality of heat transfer fins extending into the center zone of the cavity.

18. The lid of claim 17 , wherein the plurality of heat transfer fins further comprises:
a first plurality of heat transfer fins extending from an interior bottom surface of the top housing; and
a second plurality of heat transfer fins extending from an interior top surface of the bottom housing, the second plurality of heat transfer fins interleaving with the first plurality of heat transfer fins.

19. The lid of claim 17 further comprising:
a plurality of pins extending from the bottom exterior surface of the bottom housing.

Assignees

• Xilinx Inc

Inventors

• Refai-Ahmed Gamal
• Lee Tien-Yu
• Fernandez Ferdinand F
• Ramalingam Suresh
• Barber Ivor G
• Singh Inderjit
• Zohni Nael

Classifications

• H10W70/63

  Vias, e.g. via plugs · CPC title

• H10W72/073

  of die-attach connectors · CPC title

• H10W72/072

  of bump connectors · CPC title

• H10W72/877

  Bump connectors and die-attach connectors · CPC title

• H10W72/856

  Bump connectors and die-attach connectors (bumps embedded in underfills H10W74/15) · CPC title