High density memory module using stacked printed circuit boards

• US 7,254,036 B2
• Filed: 04/07/2005
• Issued: 08/07/2007
• Est. Priority Date: 04/09/2004
• Status: Active Grant

• Current Assignee: Netlist, Inc.
• Original Assignee: Netlist, Inc.
• Inventors: Bhakta, Jayesh R., Delvalle, Jose, Chen, Chi She, Gervasi, William M., Pauley, Robert S.
• Primary Examiner(s): CHERVINSKY, BORIS LEO
• Application Number:
  US11/101,155
• Publication Number:
  US 20060044749A1
• Time in Patent Office: 852 Days
• Field of Search: None
• US Class Current: 361/721
• CPC Class Codes: H05K 1/0203 Cooling of mounted components H05K1/0272 takes precedence
• CPC Class Codes: H05K 1/144 Stacked arrangements of planar printed circuit boards
• CPC Class Codes: H05K 2201/10189 Non-printed connector
• CPC Class Codes: H05K 2201/1056 Metal over component, i.e. metal plate over component mounted on or embedded in PCB
• CPC Class Codes: H05K 2201/2018 Presence of a frame in a printed circuit or printed circuit assembly
• CPC Class Codes: Y10T 29/49117 Conductor or circuit manufacturing
• CPC Class Codes: Y10T 29/49124 On flat or curved insulated base, e.g., printed circuit, etc.
• CPC Class Codes: Y10T 29/4913 Assembling to base an electrical component, e.g., capacitor, etc.

Abstract

A module is electrically connectable to a computer system. The module includes a frame having an edge connector with a plurality of electrical contacts which are electrically connectable to the computer system. The module further includes a first printed circuit board coupled to the frame. The first printed circuit board has a first surface and a first plurality of components mounted on the first surface. The first plurality of components is electrically coupled to the electrical contacts of the edge connector. The module further includes a second printed circuit board coupled to the frame. The second printed circuit board has a second surface and a second plurality of components mounted on the second surface. The second plurality of components is electrically coupled to the electrical contacts of the edge connector. The second surface of the second printed circuit board faces the first surface of the first printed circuit board. The module further includes at least one thermally conductive layer positioned between the first plurality of components and the second plurality of components. The at least one thermally conductive layer is thermally coupled to the first plurality of components, to the second plurality of components, and to the electrical contacts of the edge connector.

Claims

1. A module electrically connectable to a computer system, the module comprising:

a frame having an edge connector with a plurality of electrical contacts which are electrically connectable to the computer system;

a first printed circuit board coupled to the frame, the first printed circuit board having a first surface and a first plurality of components mounted on the first surface, the first plurality of components electrically coupled to the electrical contacts of the edge connector;

a second printed circuit board coupled to the frame, the second printed circuit board having a second surface and a second plurality of components mounted on the second surface, the second plurality of components electrically coupled to the electrical contacts of the edge connector, the second surface of the second printed circuit board facing the first surface of the first printed circuit board; and

at least one thermally conductive layer positioned between the first plurality of components and the second plurality of components, the at least one thermally conductive layer thermally coupled to the first plurality of components, to the second plurality of components, and to the electrical contacts of the edge connector.

2. The module of claim 1, wherein the at least one thermally conductive layer comprises copper.

3. The module of claim 2, wherein the layer has a thickness of approximately 0.2 millimeter.

4. The module of claim 2, wherein the at least one thermally conductive layer comprises a two-ounce copper sheet.

5. The module of claim 1, wherein the thermally conductive layer conducts heat away from the first plurality of components and from the second plurality of components to the computer system through the electrical contacts of the edge connector.

6. The module of claim 1, wherein the module has a thickness of less than approximately 5.6 millimeters.

7. The module of claim 1, wherein the first printed circuit board and the second printed circuit board are stacked and are generally parallel to one another.

8. The module of claim 1, wherein the components comprise memory integrated circuits.

9. The module of claim 8, wherein the memory integrated circuits comprise dynamic random-access memory (DRAM) integrated circuits.

10. The module of claim 9, wherein at least some of the memory integrated circuits are stacked.

11. A module connectable to a computer system, the module comprising:

a frame comprising an edge connector connectable to the computer system;

a first printed circuit board coupled to the frame, the first printed circuit board having a first surface and a first plurality of components mounted on the first surface, the first plurality of components electrically coupled to the edge connector;

a second printed circuit board coupled to the frame, the second printed circuit board having a second surface and a second plurality of components mounted on the second surface, the second plurality of components electrically coupled to the edge connector, the second surface facing the first surface; and

a heat spreader comprising at least one sheet of thermally conductive material, the heat spreader positioned between and thermally coupled to the first plurality of components and the second plurality of components, the heat spreader thermally coupled to the edge connector.

12. The module of claim 11, wherein the thermally conductive material comprises copper.

13. The module of claim 12, wherein the sheet has a thickness of approximately 0.2 millimeter.

14. The module of claim 12, wherein the heat spreader comprises a two-ounce copper sheet.

15. The module of claim 11, wherein the heat spreader conducts heat away from the first plurality of components and from the second plurality of components to the computer system through the edge connector.

16. The module of claim 11, wherein the first printed circuit board and the second printed circuit board are stacked and are generally parallel to one another.

17. The module of claim 11, wherein the components comprise memory integrated circuits.

18. The module of claim 17, wherein the memory integrated circuits comprise dynamic random-access memory (DRAM) integrated circuits.

19. The module of claim 18, wherein at least some of the memory integrated circuits are stacked.

20. A method of conducting heat away from a first plurality of components mounted on a first surface of a first printed circuit board and from a second plurality of components mounted on a second surface of a second printed circuit board, the method comprising:

coupling the first printed circuit board and the second printed circuit board to a frame comprising an edge connector, the first surface facing the second surface;

positioning a thermally conductive layer between the first plurality of components and the second plurality of components;

thermally coupling the thermally conductive layer to the first plurality of components, to the second plurality of components, and to the edge connector; and

electrically and thermally coupling the edge connector to a computer system, thereby providing a thermal pathway for heat to be removed from the first plurality of components and from the second plurality of components to the computer system through the edge connector.

21. A method of fabricating a module electrically connectable to a computer system, the method comprising:

providing a frame comprising an edge connector electrically connectable to the computer system, the frame further comprising at least one layer of thermally conductive material which is thermally coupled to the edge connector;

mounting a first printed circuit board to the frame, the first printed circuit board having a first surface and a first plurality of components mounted on the first surface, the first plurality of components electrically coupled to the edge connector and thermally coupled to the at least one layer of thermally conductive material; and

mounting a second printed circuit board to the frame, the second printed circuit board having a second surface and a second plurality of components mounted on the second surface, the second plurality of components electrically coupled to the edge connector and thermally coupled to the at least one layer of thermally conductive material.