High density memory module using stacked printed circuit boards

• US 7,375,970 B2
• Filed: 07/09/2007
• Issued: 05/20/2008
• Est. Priority Date: 04/09/2004
• Status: Expired due to Fees

• 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:
  US11/775,125
• Publication Number:
  US 20080007921A1
• Time in Patent Office: 316 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 at least one multilayer structure having 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 at least one multilayer structure. 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 in electrical communication with the electrical contacts. The module further includes a second printed circuit board coupled to the at least one multilayer structure. 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 in electrical communication with the electrical contacts. 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 in thermal communication with the first plurality of components, the second plurality of components, and the electrical contacts.

Claims

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

at least one multilayer structure having a plurality of electrical contacts which are electrically connectable to the computer system;

a first printed circuit board coupled to the at least one multilayer structure, 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 in electrical communication with the electrical contacts;

a second printed circuit board coupled to the at least one multilayer structure, 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 in electrical communication with the electrical contacts, 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 in thermal communication with the first plurality of components, the second plurality of components, and the electrical contacts.

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

3. The module of claim 1, wherein the at least one multilayer structure comprises at least one printed circuit board in electrical communication with the first printed circuit board and with the second printed circuit board.

4. The module of claim 3, wherein the at least one printed circuit board comprises an edge connector comprising the plurality of electrical contacts.

5. The module of claim 1, wherein the at least one multilayer structure comprises a lamination of layers of electrically insulative materials and electrically conductive materials.

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:

at least one multilayer structure connectable to the computer system;

a first printed circuit board in electrical communication with the at least one multilayer structure, 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 in electrical communication with the computer system when the at least one multilayer structure is connected to the computer system;

a second printed circuit board in electrical communication with the at least one multilayer structure, 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 in electrical communication with the computer system when the at least one multilayer structure is connected to the computer system, 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 in thermal communication with the first plurality of components and the second plurality of components, the heat spreader in thermal communication with the computer system when the at least one multilayer structure is connected to the computer system.

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

13. The module of claim 11, wherein the at least one multilayer structure comprises at least one printed circuit board in electrical communication with the first printed circuit board and with the second printed circuit board.

14. The module of claim 13, wherein the at least one printed circuit board comprises an edge connector comprising a plurality of electrical contacts.

15. The module of claim 11, wherein the at least one multilayer structure comprises a lamination of layers of electrically insulative materials and electrically conductive materials.

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 at least one multilayer structure, 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 at least one multilayer structure; and

electrically and thermally coupling the at least one multilayer structure 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 at least one multilayer structure.

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

providing at least one multilayer structure electrically connectable to the computer system, the at least one multilayer structure comprising at least one layer of thermally conductive material which is thermally coupled to the computer system when the at least one multilayer structure is electrically connected to the computer system;

mounting a first printed circuit board to the at least one multilayer structure, 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 at least one multilayer structure and thermally coupled to the at least one layer of thermally conductive material; and

mounting a second printed circuit board to the at least one multilayer structure, 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 at least one multilayer structure and thermally coupled to the at least one layer of thermally conductive material.